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Sample records for tailings deposit elliot

  1. Radionuclide levels in vegetation growing on uranium tailings, Elliot Lake, Ontario

    International Nuclear Information System (INIS)

    Pave, N.K.; Cloutier, N.R.; Lim, T.P.

    1985-01-01

    In Elliot Lake, Ontario, Canada, most of the inactive uranium tailings have been reclaimed by revegetation where a thick vegetation cover has been established. The surface amendments have also prompted volunteer growth of various species of local trees and shrubs on tailings. Radionuclide levels were measured in various tissues of grasses, legumes and trees growing on uranium tailings at different sites. Lower Th than Ra and Pb levels in tailings substrate were believed to be the cause for the relatively lower Th levels measured in vegetation when compared to Ra and Pb concentrations. No correlation was observed between the level of a given radionuclide in tailings and in the vegetation growing on that tailings

  2. Influence of uranium mill tailings on tree growth at Elliot Lake

    International Nuclear Information System (INIS)

    Murray, D.R.

    1978-01-01

    A four-year study was carried out to determine the ability of coniferous trees to aid in the reclamation of uranium tailings at Elliot Lake. Five species were planted: white cedar, white spruce, jack pine, scotch pine and red pine. More than 570 bare-root, two-year-old seedlings were planted on bare tailings and in areas of established grasses. A further division was made between areas of coarse and fine tailings. Over-all survival and growth of the trees has been far below expectations based on previous experience with several varieties of grasses. The criteria for assessment have been per cent survival and yearly growth as determined by plant height. Pine was superior, with 68% survival when planted in bare coarse tailings, 45% for vegetated coarse tailings and 34% for vegetated fine tailings. Cedar had the worst survival rates at 49%, 14% and 7% respectively. No species survived on bare fine tailings. The survival and growth of the coniferous trees have been related to species, environmental conditions and tailings properties. (author)

  3. Influence of uranium mill tailings on tree growth at Elliot Lake

    International Nuclear Information System (INIS)

    Murray, D.R.

    1978-01-01

    A four year study was carried out to determine the ability of coniferous trees to aid in the reclamation of uranium tailings at Elliot Lake. Five species were planted: white cedar, white spruce, jack pine, scotch pine and red pine. More than 570 bare-root, two-year-old seedlings were planted on bare tailings and in areas of established grasses. A further division was made between areas of coarse and fine tailings. Over-all survival and growth of the trees has been far below expectations based on previous experience with several varieties of grasses. The crieteria for assessment have been per cent survival and yearly growth as determined by plant height. Pine was superior, with 68% survival when planted in bare coarse tailings, 45% for vegetated coarse tailings and 34% for vegetated fine tailings. Cedar had the worst survival rates at 49%, 14% and 7% respectively. No species survived on bare fine tailings. The survival and growth of the coniferous trees have been related to species, environmental conditions and tailings properties. (auth)

  4. Modelling of the underwater disposal of uranium mine tailings in Elliot Lake

    International Nuclear Information System (INIS)

    Halbert, B.E.; Scharer, J.M.; Chakravatti, J.L.; Barnes, E.

    1982-01-01

    Underwater disposal of uranium mine tailings from the Elliot Lake area operations offers potential advantages in controlling radon gas release, emission of airborne particulate matter, and acid production from pyrites in the tailings. In addition, the proximity of the three active properties, one owned by Denison Mines Limited and two by Rio Algom Limited, to a large deep lake has spurred interest in the concept. It has been estimated that the placement of approximately 150 million tonnes of tailings from future planned production would occupy less than 20% of the lake volume. To assess the applicability of the underwater tailings disposal concept, a multi-stage study was developed in conjunction with the regulatory agencies. The most important facet identified for investigation during the first-stage investigations was an assessment of the effects of underwater disposal on water quality in the Serpent River Basin watershed. To simulate the effects of underwater disposal, a computer simulation routine was developed and integrated with a water quality model previously developed for the Basin which predicts levels of total dissolved solids, ammonia, dissolved radium-226 and pH. The underwater disposal model component reflects the effects of direct input of tailings into the hypolimnion, the chemical/biological transformation of dissolved constituents in the water column, the reactions of pyritic tailings deposited on the bottom, and the flux of dissolved constituents from the tailings into the water column. To establish site-specific values for the underwater disposal model, field and laboratory experiments were utilized to evaluate rates of pyrite and ammonia oxidation, and pH-alkalinity relationships. The results of these studies and their use in the water quality model are discussed. In addition, the results of two model run simulations are presented. (author)

  5. Radionuclide uptake by various plants growing on uranium tailings, Elliot Lake, Ontario

    International Nuclear Information System (INIS)

    Dave, N.K.; Lim, T.P.; Cloutier, N.R.

    1984-02-01

    Detectable levels of Ra-226 (0.2 to 27.6 pCi/g), Ra-223 (<= 0.1 to 4.3 pCi/g) and Pb-210 (0.6 to 6.9 pCi/g) were measured in various species of vegetation growing on various uranium tailings in Elliot Lake. On the other hand levels of Th-232 (<= 0.1 pCi/g), Th-230 (<= 0.1 pCi/g) were near detection limits in the same vegetation samples. In tailings substrates, all radionuclides investigated were detectable: Ra-226 (8.8 to 552 pCi/g), Ra-223 (3.1 to 213 pCi/g), Pb-210 (5.4 to 441 pCi/g), Th-232 (1.6 to 15.4 pCi/g), Th-230 (4.9 to 62 pCi/g) and Th-228 (1.3 to 38 pCi/g). Lower Th than Ra and Pb levels in tailings substrate were believed to be the cause for the relatively lower Th levels measured in vegetation when compared to Ra and Pb concentrations. No correlation was observed between the level of a given radionuclide in tailings and in the vegetation growing on that tailings

  6. Ra-226 concentrations in blueberries Vaccinium angustifolium Ait. near an inactive uranium tailings site in Elliot Lake, Ontario, Canada

    International Nuclear Information System (INIS)

    Dave, N.K.; Lim, T.P.; Cloutier, N.R.

    1985-01-01

    Ra-226 concentrations were measured in blueberries growing around the Stanrock uranium tailings area near Elliot Lake, Ontario, Canada. Elevated levels of total Ra-226 ranging between 20 to 290 mBq g -1 were observed in samples collected within 500 m from the tailings. Highest levels, approx. 285 mBq g -1 , were observed in a sample collected on a tailings spill. For sites located more than 500 m away in the upwind direction, and those situated at distances greater than 1 km downwind from the waste pile, the total Ra-226 concentrations approached background levels which were measured as 2 to 6 mBq g -1 . Approximately 17% of the total Ra-226 measured was removable by washing the samples with distilled water. Wind dispersal of the tailings material and its deposition in the form of dust on blueberries was believed to be responsible for the external contamination. Based on the ICRP recommended dose limits for oral intake of Ra-226, it was calculated that approximately 160 kg a -1 , 3350 kg a -1 and 47 kg a -1 of washed blueberries from inside and outside the influenced zone, and from the tailings spill site, respectively, would need to be consumed before the individual annual limit for the general public was exceeded. (author)

  7. A study of facilities relative to stabilization of uranium mill tailings at Elliot Lake

    International Nuclear Information System (INIS)

    1983-06-01

    The total project capital cost of facilities to stabilize uranium mill tailings at Elliot Lake while producing 350,000 short tons per year of sulphuric acid and 266,000 short tons per year of triple superphosphate is approximately 153 million dollars. This includes pyrite flotation, roasting, acid and phosphate production, site preparation, utilities and project overhead. A new operating credit of 20.43 dollars per short ton of acid is estimated, achieved from the sale of steam and fertilizer. Two alternatives to the above were also examined, as follows: a) Production of 596,000 short tons per year of acid, and the sale of 246,000 short tons which are in excess of the Elliot Lake mill's requirement. The capital cost of this scheme is approximately 89 million dollars, with a net operating credit of 14.97 dollars per short ton of acid. b) Production of only 350,000 short tons per year of acid. This would entail disposal of the excess pyrite floated from the Rio Algom mills. The capital cost of this scheme is approximately 75 million dollars, with an operating cost of 10.47 dollars per short ton of acid

  8. Close-out concepts for the Elliot Lake uranium mining operations

    International Nuclear Information System (INIS)

    Culver, K.B.; Chakravatti, J.L.; Gorber, D.M.; Knapp, R.A.; Davis, J.B.

    1982-01-01

    In the Elliot Lake area, approximately 100 million tonnes of tailings have been generated and deposited in ten separate management areas covering a total of 460 hectares. With continued placement of tailings into land-based management areas, the ultimate combined area covered with tailings would be in the order of 1500 to 2000 hectares. The principal environmental concerns associated with the land-based management areas in the long term (after mining has ceased), as seen by the Canadian regulatory authorities, are the potential of acid generation from pyrite oxidation, and the release and migration of radionuclides into air and water. The development of close-out criteria and concepts, therefore, has focussed on addressing these concerns. A position paper was issued for comment by the Canadian Atomic Energy Control Board on long-term aspects of uranium tailings management. In response, three of the uranium companies, Rio Algom Limited, Denison Mines Limited, and Eldorado Nuclear Limited, have countered with their own position and supported it with the extensive research on close-out procedures that has been carried out on their properties. The companies' position is that regulations should allow for site specific solutions and that institutional control is a valid long-term control option. As radiological loadings to air and water in the long term will be less than during operations, the only long-term concern in Elliot Lake is pyrite oxidation. Research has indicated that pyrite oxidation can be controlled in the upper zone of tailings. A summary of options available to control pyrite oxidation in this upper zone, including vegetation, limestone addition, pyrite removal, and physical cover is presented as well as preliminary cost estimates of each alternative. (author)

  9. Uranium mineralization in the Molteno and Elliot Formations

    International Nuclear Information System (INIS)

    Le Roux, J.P.

    1990-01-01

    To date very little has been published on the uranium deposits of the Molteno and Elliot Formations. Two selected deposits from these formations are described and compared to the uranium occurrences of the Beaufort Group. Whereas the latter are generally confined to channel zones due to the fine grain size and impermeable nature of the host sandstones, uranium in the Molteno and Elliot Formations seems to be concentrated in the less permeable 'island' areas. An apparent association with dolerite sills and dykes also suggests that the host sandstones were still sufficiently permeable after intrusion of the dolorite so that ground waters could remobilize the uranium. This agrees with recently published isotopic ages for the mineralization. There is a distinct possibility that roll-type uranium deposits may be present in the Molteno and Elliot Formations, and any future exploration should bear this in mind. 9 figs., 1 tab., 16 refs

  10. 226Ra and other radionuclides in water, vegetation, and tissues of beavers (Castor canadensis) from a watershed containing U tailings neat Elliot Lake, Canada

    International Nuclear Information System (INIS)

    Clulow, F.V.; Mirka, M.A.; Dave, N.K.; Lim, T.P.

    1991-01-01

    Radionuclide levels were measured in tissues, gut contents, diet items, and water at site of capture, of adult beavers from the Serpent River drainage basin which contains U tailings at Elliot Lake, Ontario, and from nearby control sites. Levels of 226 Ra in beaver bone, muscle and kidney were highest in animals from locations close to U tailing; liver levels did not vary by site. Environmental 226 Ra levels were within ranges previously reported at these or similar locations elsewhere; levels in beaver gut contents reflected levels in diet items. Concentration ratios exceeded unity only between some vegetation items and beaver bone at the Elliot Lake site and were less than 0.19 between vegetation and other tissues. In two beavers with tissue levels of 226 Ra higher than others sampled, neither 232 Th nor 230 Th were detected in bone, muscle or liver tissues. U-238 was measurable in bone, muscle and liver; 228 Th in bone, 210 Po bone, muscle and liver; and 210 Pb was measurable only in bone. Estimated yearly intakes of radionuclides by people eating beavers were calculated to be below current allowable levels set by the Canadian regulatory authorities. (author)

  11. contaminant migration in a sand aquifer near an inactive uranium tailings impoundment, Elliot Lake, Ontario

    International Nuclear Information System (INIS)

    Morin, K.A.; Cherry, J.A.

    1982-01-01

    An investigation of the movement of contaminated groundwater from inactive uranium tailings through a sand aquifer is being conducted at the Nordic Main tailings impoundment near Elliot Lake, Ontario. During 1979 and 1980, multilevel bundle-type piezometers were installed at several locations around the edge of the tailings impoundment. Chemical analysis of water samples from the bundle piezometers indicate that a major contaminant plume extends outward through a sand aquifer from the southeastern part of the Nordic Main impoundment dam. In the vincinity of the contaminant plume, the sand aquifer varies in thickness from about 9 to 15 m. The plume has two distinct segments, referred to as the inner core and the outer zone. The inner core, which has a pH of 4.3-5.0 and extends about 15 m from the foot of the tailings dam, contains several grams per litre of iron and sulfate, and tens of pCi/L of 226 Ra and 210 Pb. Water levels in piezometers within the inner core show that groundwater is moving horizontally, away from the tailings impoundment, with a velocity of up to several hundred metres per year. The outer zone, which extends a few hundred metres downgradient from the dam, is characterized by hundreds to thousands of milligrams per litre of iron and sulfate, less than 15pCi/L of 226 Ra, and a pH greater than 5.7. Comparison of 1979 and 1980 data shows that the front of the inner core is advancing a few metres per year, which is less than a few percent of the groundwater velocity. This retardation of movement of the inner core is caused by neutralization of the acidic water as a result of dissolution of calcium carbonate in the sand. With the rise in pH, precipitation of iron carbonate and possibly some iron hydroxide occurs and the contaminants of main concern such as 226 Ra, 210 Pb, and uranium are removed from solution by adsorption or coprecipitation

  12. Canadian experience with uranium tailings disposal

    International Nuclear Information System (INIS)

    Culver, K.B.

    1982-06-01

    During the first years of uranium production in Canada uranium tailings were discharged directly into valleys or lakes near the mill. Treatment with barium chloride to precipitate radium began in 1965 at the Nordic Mine at Elliot Lake, Ontario. In the mid-60s and early 70s water quality studies indicated that discharges from uranium tailings areas were causing degradation to the upper part of the Serpent River water system. Studies into acid generation, revegetation, and leaching of radium were initiated by the mining companies and resulted in the construction of treatment plants at a number of sites. Abandoned tailings sites were revegetated. At hearings into the expansion of the Elliot Lake operations the issue of tailings management was a major item for discussion. As a result federal and provincial agencies developed guidelines for the siting and development of urnaium tailings areas prior to issuing operating licences. Western Canadian uranium producers do not have the acid generation problem of the Elliot Lake operations. The Rabbit Lake mill uses settling ponds followed by filtration. High-grade tailings from Cluff Lake are sealed in concrete and buried. Uranium producers feel that the interim criteria developed by the Atomic Energy Control Board, if adopted, would have a harmful effect on the viability of the Canadian uranium industry

  13. Sub-aerial tailings deposition

    International Nuclear Information System (INIS)

    Knight, R.B.; Haile, J.P.

    1984-01-01

    The sub-aerial technique involves the systematic deposition of tailings in thin layers and allowing each layer to settle, drain and partially air dry prior to covering with a further layer. Underdrainage produces densities in excess of those achieved by sub-aqueous deposition and any air-drying serves to preconsolidate each layer with a resulting further increase in density. The low permeability of the tailings surface resulting from this deposition technique results in high runoff coefficients and, by decanting the runoff component of direct precipitation, a net evaporation condition can be achieved even in high rainfall areas. An underdrainage system prevents the build-up of excess pore-pressures within the tailings mass and at decommissioning the tailings are fully consolidated and drained thereby eliminating the possibility of any long term seepage. This paper presents a general description of these design concepts, and details of two projects where the concepts have been applied

  14. Recent Developments in the Treatment of Uranium Ores from the Elliot Lake District

    Energy Technology Data Exchange (ETDEWEB)

    Downes, K W [Extraction Metallurgy Division, Department of Mines and Technical Surveys, Ottawa (Canada)

    1967-06-15

    A summary of the results obtained during investigations on the treatment of uranium ores from the Elliot Lake district in the laboratories of the Mines Branch, and of developments in operating procedures introduced in the uranium mills in the Elliot Lake district, is presented. Concentration of Elliot Lake ore on a pilot-plant scale by a combined gravity-flotation procedure yielded a 90% recovery of uranium at a ratio of concentration of 2.4 to 1.0. The mineralogical composition of the ore, the flow sheet used and the reagents employed are described. An approximate cost estimate indicates that, although the capacity of an existing uranium leaching plant would be doubled by introducing the procedure, the production cost per pound of U{sub 3}0{sub 8} would not be affected. Bacterial leaching of Elliot Lake ore on a laboratory scale yielded, under favourable conditions, extractions of 90 per cent in 5 weeks, and of 95 per cent in 15 weeks. The conditions that were found to influence the leaching results are outlined, and the effects of the leaching solutions are discussed. The purification of ion exchange eluates by liquid-liquid extraction, using tri-n-butyl phosphate, dibutyl butylphosphonate and tri-capryl amine in a continuous process, yielded solutions from which refined ammonium diuranate was precipitated using gaseous ammonia. The effectiveness of the three extractants is discussed, and the effects of the procedures employed on the production costs per pound of U{sub 3}O{sub 8} is estimated. Some improvements in operating procedures introduced in the Elliot Lake district uranium mills are briefly described, and their effects on the operations are indicated. Present methods of controlling radiological pollution of drainage waters by uranium mill tailings are outlined. (author)

  15. Description of the Panel Mine tailings area Rio Algom Ltd., Elliot Lake, Ontario, Canada

    International Nuclear Information System (INIS)

    Pullen, P.F.; Davis, J.B.

    1982-01-01

    The geomorphological setting of the Panel Mine tailings management area is described in relation to the geology of the Canadian Shield subject to recent glaciation and subsequent weathering and erosion in a humid climate with temperature extremes. For the deposition of uranium tailings a topographic low is chosen that is surrounded by bedrock with a low water permeability. This latter is evaluated by a detailed geological investigation and by drilling to investigate the relative pemeability of suspected seepage paths. It is estimated that seepage from the basin used will be less than one litre per second. Monitor wells have been established to determine the quality of the groundwater flows

  16. ESTIMATION OF FILTRATION CAPACITY OF POSTFLOTATION TAILINGS EMBEDDED IN DAMS OF TAILINGS DEPOSITION SITES

    Directory of Open Access Journals (Sweden)

    Wojciech Tschuschke

    2015-10-01

    Full Text Available Construction of very big mine tailings deposition sites, such as postflotation tailings ponds, is a complicated engineering task, in which several technical and environmental problems need to be solved. Designing, construction and operation of such an object applying the monitoring method consists in the verification of design assumptions based on continuous observations. One of the primary tasks of monitoring while the deposition site is being filled with tailings is to control quality of the formed dam embankments, as the structural element of the object responsible for its stability. In order to use material selected from deposited tailings in the construction of dams it is necessary to define grain size and compaction criteria, which directly affect load bearing capacity and deformation of the structure. For this reason main control tests include the analyses of grain size distribution and physical properties of the material embedded in the dams. These data may also be used to estimate filtration capacity of the embankment. A lack of drainage, causing accumulation of water within the embankment, may potentially deteriorate stability conditions. This paper presents the use of empirical formulas, i.e. formulas typically applied to natural soils, to assess permeability coefficient of tailings. A simple empirical formula was also proposed for the estimation of permeability coefficient of tailings based on grain size and compaction parameters determined in routine quality tests of constructed dam embankments.

  17. Effects of various tailings covers on radon gas emanation from pyritic uranium tailings

    International Nuclear Information System (INIS)

    Dave, N.K.; Lim, T.P.

    1987-01-01

    Radon emanation studies were carried out at an inactive pyritic uranium tailings site in Elliot Lake, Ontario, Canada, to evaluate the effects of various existing dry and wet covers on radon flux rates. Measurements were taken using activated charcoal cartridges for various surface covers consisting of bare, vegetated, acidophilic moss with high degree of water saturation, compacted crushed rock and gravel, and winter snow. The results showed that at a given site, there was no significant difference in radon emanation rates between various tailings covers and bare tailings. In particular, no increase In radon emanation rates from vegetated areas compared to bare tailings was observed. Radon emanation rates varied spatially depending on tailings grain size, porosity, moisture content and on pressure and water table variations. The emanation rates were higher for tailings with low water contents compared to those for wet and moss covered tailings

  18. Windblown Dust Deposition Forecasting and Spread of Contamination around Mine Tailings.

    Science.gov (United States)

    Stovern, Michael; Guzmán, Héctor; Rine, Kyle P; Felix, Omar; King, Matthew; Ela, Wendell P; Betterton, Eric A; Sáez, Avelino Eduardo

    2016-02-01

    Wind erosion, transport and deposition of windblown dust from anthropogenic sources, such as mine tailings impoundments, can have significant effects on the surrounding environment. The lack of vegetation and the vertical protrusion of the mine tailings above the neighboring terrain make the tailings susceptible to wind erosion. Modeling the erosion, transport and deposition of particulate matter from mine tailings is a challenge for many reasons, including heterogeneity of the soil surface, vegetative canopy coverage, dynamic meteorological conditions and topographic influences. In this work, a previously developed Deposition Forecasting Model (DFM) that is specifically designed to model the transport of particulate matter from mine tailings impoundments is verified using dust collection and topsoil measurements. The DFM is initialized using data from an operational Weather Research and Forecasting (WRF) model. The forecast deposition patterns are compared to dust collected by inverted-disc samplers and determined through gravimetric, chemical composition and lead isotopic analysis. The DFM is capable of predicting dust deposition patterns from the tailings impoundment to the surrounding area. The methodology and approach employed in this work can be generalized to other contaminated sites from which dust transport to the local environment can be assessed as a potential route for human exposure.

  19. Elliot Lake progress report

    International Nuclear Information System (INIS)

    Findlay, W.; Scott, A.S.

    1980-01-01

    The intent of the Elliot Lake remedial program is to identify houses in Elliot Lake with annual average WL's in excess of 0.02, discover the routes of radon entry into identified houses and close enough of them to reduce the annual average WL to an acceptable level, and to demonstrate that the annual average WL is below 0.02 in houses where remedial work was not thought necessary as well as in houses where remedial work has been completed. The remedial program is organized into two subprograms, the survey program and the remedial action program. By December 31, 1979 more than 17000 survey measurements had been carried out, identifying 157 houses where remedial action was required and confirming that no action was needed in 413 houses. Remedial work had been completed on 98 houses

  20. Hydrology of Quirke and Panel uranium tailings basins

    International Nuclear Information System (INIS)

    King, R.M.; MacPhie, L.

    1991-11-01

    The research project described by this report provides the AECB with an independent assessment of the 'saturated tailings concept' for the decommissioning of tailing areas at the Rio Algom Quirke and Panel uranium mines near Elliot Lake in Northern Ontario. Hydrologic and hydraulic modelling for each facility showed the interrelation between the design of the water-level control facilities and the water levels in each cell for design flood and extreme low-flow conditions, taking into account all water-balance components. The estimate of seepage rates through the tailings mass is identified as a critical issue

  1. Restoration of environments with radioactive residues - the Elliot Lake case study

    International Nuclear Information System (INIS)

    Knapp, R.A.

    2000-01-01

    The Elliot Lake area experienced the boom and bust of uranium mining over a 40-year period. In 1996, the last mine closed, which left nine tailings areas for closure and long term maintenance. The practices of the 1950s left a legacy of environmental damage which has been effectively reversed through remediation and closure of the mines. Detailed environmental assessments were completed on decommissioning proposals for the mines in the late 1980s and 1990s. These assessments have demonstrated that the area's ecology can be effectively protected, and that there are no impediments to the restoration of the entire Serpent River Watershed. Environmental monitoring has shown that the reclaimed sites are performing as expected, and that healthy aquatic communities are present in all major waterways in the region. (author)

  2. The uranium mine Key Lake, Canada, as an example of final deposition of radioactive tailings

    International Nuclear Information System (INIS)

    Schmitz, T.

    1984-01-01

    The main part of that waste handling system is tailing storage. The other parts include the water storage reservoirs and monitoring ponds. Soil conditions and design features of the tailings pond are described in detail as well as the method of tailings disposal. Finally the method of deposition results in a laminated radioactive tailings deposit and the tailings reach a degree of compactness comparable to concrete. The Key Lake Mining Corporation and its consultants have developed a tailings handling program in order to minimize environmental impact and to take advantage of the natural topography and soil materials in the project area. (orig./HP) [de

  3. A robotic system to characterize soft tailings deposits

    Energy Technology Data Exchange (ETDEWEB)

    Lipsett, M.G.; Dwyer, S.C. [Alberta Univ., Edmonton, AB (Canada). Dept. of Mechanical Engineering

    2009-07-01

    A robotic system for characterizing soft tailings deposits was discussed in this presentation. The system was developed to reduce variability in feedstocks and process performance as well as to improve the trafficability of composite tailings (CT). The method was designed to reliably sample different locations of a soft deposit. Sensors were used to determine water content, clay content, organic matter, and strength. The system included an autonomous rover with a sensor package and teleoperation capability. The system was also designed to be used without automatic controls. The wheeled mobile robot was used to conduct ground contact and soil measurements. The gas-powered robot included on-board microcontrollers and a host computer. The system also featured traction control and fault recovery sub-systems. Wheel contact was used to estimate soil parameters. It was concluded that further research is needed to improve traction control and soil parameter estimation testing capabilities. Overall system block diagrams were included. tabs., figs.

  4. Element flows associated with marine shore mine tailings deposits.

    Science.gov (United States)

    Dold, Bernhard

    2006-02-01

    From 1938 until 1975, flotation tailings from the Potrerillos--El Salvador mining district (porphyry copper deposits) were discharged into the El Salado valley and transported in suspension to the sea at Chaliaral Bay, Atacama Desert, northern Chile. Over 220 Mt of tailings, averaging 0.8 +/- 0.25 wt % of pyrite, were deposited into the bay, resulting in over a 1 kilometer seaward displacement of the shoreline and an estimated 10-15 m thick tailings accumulation covering a approximately 4 km2 surface area. The Chaniaral case was classified by the United Nations Environmental Programme (UNEP) in 1983 as one of the most serious cases of marine contamination in the Pacific area. Since 1975, the tailings have been exposed to oxidation, resulting in a 70-188 cm thick low-pH (2.6-4) oxidation zone at the top with liberation of divalent metal cations, such as Cu2+, Ni2+, and Zn2+ (up to 2265 mg/L, 18.1 mg/L, and 20.3 mg/ L, respectively). Evaporation-induced transport capillarity led to metal enrichment atthe tailings surface (e.g. up to 2.4% Cu) in the form of secondary chlorides and/or sulfates (dominated by eriochalcite [CuCl.H2O] and halite). These, mainly water-soluble, secondary minerals were exposed to eolian transport in the direction of the Village of Chañaral by the predominant W-SW winds. Two element-flow directions (toward the tailings surface, via capillarity, and toward the sea) and two element groups with different geochemical behaviors (cations such as Cu, Zn, Ni, and oxyanions such as As and Mo) could be distinguished. It can be postulated, that the sea is mainly affected by the following: As, Mo, Cu, and Zn contamination, which were liberated from the oxidation zone from the tailings and mobilized through the tidal cycle, and by Cu and Zn from the subsurface waters flowing in the El Salado valley (up to 19 mg/L and 12 mg/L Zn, respectively), transported as chloro complexes at neutral pH.

  5. Conceptual design of a remote system for characterizing oilsands tailings deposits

    Energy Technology Data Exchange (ETDEWEB)

    Lipsett, M.G.; Rivard, B. [Alberta Univ., Edmonton, AB (Canada). Dept. of Mechanical Engineering; Alberta Univ., Edmonton, AB (Canada). Dept. of Earth and Atmospheric Sciences

    2010-07-01

    This PowerPoint presentation described the design of a remote system for characterizing oil sands tailings deposits. The wheeled mobile robot technology was developed in order to improve the trafficability of composite tailings (CT) and other engineering tailings deposits, as well as to identify differences in feedstocks and process performance, and to determine shear strength losses from dynamic loading. The technology was comprised of a spectroscopy component, and a mobile robot equipped with surface measurement sensors. The control system included navigation and traction control devices. A communication component was also included. Tools used in the system included a penetrometer, a viscosimeter, and an automatic sample collection device. Tests have been conducted to determine the system's driving ability. Further tests are being conducted to evaluate the performance of the robot sensors and controllers. tabs., figs.

  6. Post-depositional behaviour of mercury and arsenic in submarine mine tailings deposited in Buyat Bay, North Sulawesi, Indonesia.

    Science.gov (United States)

    Shepherd, Thomas; Rumengan, Inneke; Sahami, Ali

    2018-06-01

    The post-depositional geochemical behaviour of mercury and arsenic in submarine mine tailings from the Mesel Gold Mine in Buyat Bay, North Sulawesi, Indonesia was assessed by in situ sampling of tailings porewaters using dialysis arrays and seawater and fish monitoring. Under steady-state conditions one year after cessation of tailings discharge, the calculated arsenic efflux incrementally added 0.8 μg/L of arsenic to the overlying seawater. The mercury efflux across the tailings-seawater interface was negligible. The arsenic and mercury concentration in seawater bottom samples monitored biannually during a 9-year post-closure program were 1.54 μg/L and tailings are geochemically stable. Copyright © 2018 Elsevier Ltd. All rights reserved.

  7. Evaluation of flexible membrane liners as long-term barriers for uranium mill tailings

    International Nuclear Information System (INIS)

    1984-07-01

    The National Uranium Tailings Program has commissioned a study to evaluate flexible membrane liners (geomembranes) as long-term barriers for Canadian uranium mill tailings. This study reviews the common liner type and addresses flexible liners (polymeric membranes and asphalt) in detail. Liner fabrication, design, installation, and performance are reviewed. Conceptual designs are presented for basins to accommodate 20 years accumulation of uranium tailings from mills in Elliot Lake and southeastern Athabasca. Nine polymeric and three asphalt liner types have been considered with respect to the physical and chemical environment in the uranium producing areas of Canada. All materials indicate good chemical resistance to uranium wastes but are subject to installation problems

  8. Liquefaction of uranium tailings

    International Nuclear Information System (INIS)

    1992-02-01

    Numerical methods for assessing the liquefaction potential of soils are reviewed with a view to their application to uranium tailings. The method can be divided into two categories: total stress analysis, where changes in pore pressure are not considered in the soil model, and effective stress analysis, where changes in pore pressure are included in the soil model. Effective stress analysis is more realistic, but few computer programs exist for such analysis in two or three dimensions. A simple linearized, two-dimensional, finite element effective stress analysis which incorporates volumetric compaction due to shear motion is described and implemented. The new program is applied to the assessment of liquefaction potential of tailings in the Quirke Mine tailings area near Elliot Lake, Ontario. The results are compared with those of a total stress analysis. Both analyses indicate liquefaction would occur if a magnitude 6.0 earthquake were to occur near the area. However, the extent of liquefaction predicted by the effective stress analysis is much less than that predicted by the total stress analysis. The results of both methods are sensitive to assumed material properties and to the method used to determine the cyclic shear strength of the tailings. Further analysis, incorporating more in situ and/or laboratory data, is recommended before conclusions can be made concerning the dynamic stability of these tailings

  9. Development of the disposal technology research component of the national uranium tailings program

    International Nuclear Information System (INIS)

    Melis, L.A.

    1983-03-01

    The National Technical Planning Group on Uranium Tailings Research, organized by CANMET in 1980, recommended the establishment of a National Uranium Tailings Program to develop research on the long-term abandonment of uranium mine tailings. This report deals with the disposal technology component of this program and attempts to provide recommendations with respect to potential research avenues in this area. A description of uranium tailings in Canada is provided in order to identify the current situation with uranium tailings management. Uranium mining sites described include the Elliot Lake and Bancroft area of Ontario, the northern Saskatchewan properties and the two abandoned sites in the North West Territories. The description of the sites was facilitated by subdividing the tailings into inactive sites, active sites, new tailings sites and areas of tailings in a close-out situation. Methods identified as promising include subsurface disposal, in-situ leaching, prevention of pyrite oxidation and reclamation studies at abandoned sites

  10. Literature review of models for estimating soil erosion and deposition from wind stresses on uranium-mill-tailings covers

    International Nuclear Information System (INIS)

    Bander, T.J.

    1982-11-01

    Pacific Northwest Laboratory (PNL) is investigating the use of a rock armoring blanket (riprap) to mitigate wind and water erosion of an earthen radon-suppression cover applied to uranium-mill tailings. The mechanics of wind erosion, as well as of soil deposition, are discussed in this report. Several wind erosion models are reviewed to determine if they can be used to estimate the erosion of soil from a mill-tailings cover. One model, developed by W.S. Chepil, contains the most-important factors that describe variables that influence wind erosion. Particular features of other models are also discussed, as well as the application of Chepil's model to a particular tailings pile. For this particular tailings pile, the estimated erosion was almost one inch per year for an unprotected tailings soil surface. Wide variability in the deposition velocity and lack of adequate deposition models preclude reliable estimates of the rate at which airborne particles are deposited

  11. Literature review of models for estimating soil erosion and deposition from wind stresses on uranium-mill-tailings covers

    Energy Technology Data Exchange (ETDEWEB)

    Bander, T.J.

    1982-11-01

    Pacific Northwest Laboratory (PNL) is investigating the use of a rock armoring blanket (riprap) to mitigate wind and water erosion of an earthen radon-suppression cover applied to uranium-mill tailings. The mechanics of wind erosion, as well as of soil deposition, are discussed in this report. Several wind erosion models are reviewed to determine if they can be used to estimate the erosion of soil from a mill-tailings cover. One model, developed by W.S. Chepil, contains the most-important factors that describe variables that influence wind erosion. Particular features of other models are also discussed, as well as the application of Chepil's model to a particular tailings pile. For this particular tailings pile, the estimated erosion was almost one inch per year for an unprotected tailings soil surface. Wide variability in the deposition velocity and lack of adequate deposition models preclude reliable estimates of the rate at which airborne particles are deposited.

  12. Environmental hazard assessment of a marine mine tailings deposit site and potential implications for deep-sea mining.

    Science.gov (United States)

    Mestre, Nélia C; Rocha, Thiago L; Canals, Miquel; Cardoso, Cátia; Danovaro, Roberto; Dell'Anno, Antonio; Gambi, Cristina; Regoli, Francesco; Sanchez-Vidal, Anna; Bebianno, Maria João

    2017-09-01

    Portmán Bay is a heavily contaminated area resulting from decades of metal mine tailings disposal, and is considered a suitable shallow-water analogue to investigate the potential ecotoxicological impact of deep-sea mining. Resuspension plumes were artificially created by removing the top layer of the mine tailings deposit by bottom trawling. Mussels were deployed at three sites: i) off the mine tailings deposit area; ii) on the mine tailings deposit beyond the influence from the resuspension plumes; iii) under the influence of the artificially generated resuspension plumes. Surface sediment samples were collected at the same sites for metal analysis and ecotoxicity assessment. Metal concentrations and a battery of biomarkers (oxidative stress, metal exposure, biotransformation and oxidative damage) were measured in different mussel tissues. The environmental hazard posed by the resuspension plumes was investigated by a quantitative weight of evidence (WOE) model that integrated all the data. The resuspension of sediments loaded with metal mine tails demonstrated that chemical contaminants were released by trawling subsequently inducing ecotoxicological impact in mussels' health. Considering as sediment quality guidelines (SQGs) those indicated in Spanish action level B for the disposal of dredged material at sea, the WOE model indicates that the hazard is slight off the mine tailings deposit, moderate on the mine tailings deposit without the influence from the resuspension plumes, and major under the influence of the resuspension plumes. Portmán Bay mine tailings deposit is a by-product of sulphide mining, and despite differences in environmental setting, it can reflect the potential ecotoxic effects to marine fauna from the impact of resuspension of plumes created by deep-sea mining of polymetallic sulphides. A similar approach as in this study could be applied in other areas affected by sediment resuspension and for testing future deep-sea mining sites in

  13. The post-depositional accumulation of metal-rich cyanide phases in submerged tailings deposits

    International Nuclear Information System (INIS)

    Jambor, J.L.; Martin, A.J.; Gerits, J.

    2009-01-01

    The characterization and accumulation pathway of metal-rich cyanide phases in mine-contaminated Balmer Lake (Ontario, Canada) were assessed through detailed examination of sediment mineralogy and porewater composition. The near-surface deposits in the lake consist of fine-grained calcareous tailings intermixed with natural organic-rich lake sediments. The tailings contain blue to greenish Fe-dominant cyanide that has formed in situ within the tailings. X-ray diffraction confirmed the presence of a mixed ferri/ferrocyanide [Fe 4 III (Fe II (CN) 6 ) 3 ], commonly referred to as 'Prussian Blue' but it is likely other metal-cyanide complexes are present as evidenced by the distinct colour variations. The cyanide phases occur in up to 1 wt.% as discrete particles and as bedded layers, where the cyanide phases act to cement other siliceous tailings components into a heterogeneous blend. Energy Dispersion X-ray Spectroscopy (EDS) analyses indicate that the authigenic cyanide precipitates contain variable amounts of Ni, Cu and Zn. Quantitatively, the cyanide compounds represent the dominant repository for Cu in Balmer Lake sediments. For Ni and Zn, cyanide associations are secondary in importance to Fe oxyhydroxides. High-resolution porewater profiles and solubility considerations suggest that the formation of the cyanide complexes is a feature of historical (pre-1990) conditions when aqueous cyanide concentrations were higher in the lake.

  14. The post-depositional accumulation of metal-rich cyanide phases in submerged tailings deposits

    Energy Technology Data Exchange (ETDEWEB)

    Jambor, J.L. [Leslie Research and Consulting, 316 Rosehill Wynd, Tsawwassen, BC, V4M 3L9 (Canada); Martin, A.J., E-mail: ajm@lorax.ca [Lorax Environmental Services, 2289 Burrard St., Vancouver, BC, V6J 3H9 (Canada); Gerits, J. [Lorax Environmental Services, 2289 Burrard St., Vancouver, BC, V6J 3H9 (Canada)

    2009-12-15

    The characterization and accumulation pathway of metal-rich cyanide phases in mine-contaminated Balmer Lake (Ontario, Canada) were assessed through detailed examination of sediment mineralogy and porewater composition. The near-surface deposits in the lake consist of fine-grained calcareous tailings intermixed with natural organic-rich lake sediments. The tailings contain blue to greenish Fe-dominant cyanide that has formed in situ within the tailings. X-ray diffraction confirmed the presence of a mixed ferri/ferrocyanide [Fe{sub 4}{sup III}(Fe{sup II}(CN){sub 6}){sub 3}], commonly referred to as 'Prussian Blue' but it is likely other metal-cyanide complexes are present as evidenced by the distinct colour variations. The cyanide phases occur in up to 1 wt.% as discrete particles and as bedded layers, where the cyanide phases act to cement other siliceous tailings components into a heterogeneous blend. Energy Dispersion X-ray Spectroscopy (EDS) analyses indicate that the authigenic cyanide precipitates contain variable amounts of Ni, Cu and Zn. Quantitatively, the cyanide compounds represent the dominant repository for Cu in Balmer Lake sediments. For Ni and Zn, cyanide associations are secondary in importance to Fe oxyhydroxides. High-resolution porewater profiles and solubility considerations suggest that the formation of the cyanide complexes is a feature of historical (pre-1990) conditions when aqueous cyanide concentrations were higher in the lake.

  15. Decommissioning of denison and Stanrock tailings management areas

    International Nuclear Information System (INIS)

    Ludgate, I.R.; Counsell, H.C.; Knapp, R.; Feasby, D.G.

    2000-01-01

    The Denison Mines Limited uranium mining and milling facility in Elliot Lake ceased operations in April of 1992. Since that time major site decommissioning projects were completed. These projects involved demolition of site facilities and acid mine drainage (AMD) mitigation in the three tailings management areas known as TMA-1, TMA-2 at Denison and TMA-3 at Stanrock. The work on TMA-1 and TMA-2 was generally completed in late 1996 and the work at TMA-3 was essentially completed in late 1998. The use of water covers was chosen as the best technology for long term tailings stabilization for TMA-1 and -2. In the gently sloped and partially flooded basin of TMA-1, 1.83 million cubic metres of tailings were dredged and relocated to deeper areas of the basin to establish 0.9 metre water cover (also termed 'dredge the wedge'). Perimeter dams were regraded to add additional factors of safety and an upstream seepage reduction berm and a downstream toe stabilization berm were constructed at, the western most dam, Dam 10. (author)

  16. Doses resulting from intrusion into uranium tailings areas

    International Nuclear Information System (INIS)

    Walsh, M.L.

    1986-02-01

    In the future, it is conceivable that institutional controls of uranium tailings areas may cease to exist and individuals may intrude into these areas unaware of the potential radiation hazards. The objective of this study was to estimate the potential doses to the intruders for a comprehensive set of intrusion scenarios. Reference tailings areas in the Elliot Lake region of northern Ontario and in northern Saskatchewan were developed to the extent required to calculate radiation exposures. The intrusion scenarios for which dose calculations were performed, were categorized into the following classes: habitation of the tailings, agricultural activities, construction activities, and recreational activities. Realistic exposure conditions were specified and annual doses were calculated by applying standard dose conversion factors. The exposure estimates demonstrated that the annual doses resulting from recreational activities and from construction activities would be generally small, less than twenty millisieverts, while the habitational and agricultural activities could hypothetically result in doses of several hundred millisieverts. However, the probability of occurrence of these latter classes of scenarios is considered to be much lower than scenarios involving either construction or recreational activities

  17. Characterization of a coal tailing deposit for zero waste mine in the Brazilian coal field of Santa Catarina

    International Nuclear Information System (INIS)

    Amaral Filho, J.R.; Schneider, I.A.H.; Tubino, R.M.C.; Brum de, I.A.S.; Miltzarek, G.; Sampaio, C.H.

    2010-01-01

    Coal tailings deposits in Brazil are occupying large areas of land while also generating acid mine drainage (AMD) that includes heavy metals. This paper described an analytical study of a typical coal tailings deposit. The study objective was to separate low density, intermediate density, and high density fractions for future reuse. Particle size analysis, disymmetric studies, X-ray diffraction, and tests conducted to determine ash, total sulphur, and acid bases were conducted in order to characterize the coal tailings samples. Results of the study demonstrated a size distribution of 67 percent coarse, 14 percent fine, and 19 percent ultra-fine particles. The gravimetric concentration method was used to recover 34.2 percent of the total deposit for future energy use. Approximately 9.2 percent of the remaining deposit was a pyrite concentrate. The acid generating potential of the remaining materials was reduced by approximately 60 percent. 9 refs., 1 tab., 2 figs.

  18. Elliot Lake uranium mine reclamation, the first ten years

    International Nuclear Information System (INIS)

    Payne, R.A.

    2000-01-01

    In 1989, Rio Algom Limited finalized its plans for the closure and subsequent decommissioning of two of its then three operating mines in Elliot Lake as a result of market conditions. These two mines closed in August 1990. These mine closures had significant impacts. The principal mining operations of Rio Algom at that time were still in Elliot Lake and had been the very foundation of the company for about 40 years. The business impact on the Corporation was regarded as possibly severe. The resultant layoff of over 1,500 long-term, highly qualified, skilled and well-paid employees, a devastating blow to the affected employees and their families, would have a significant financial impact on the municipal economy, particularly as this announcement was seen as the first step in the early closure of all four operating mines in the region. At that time there was little precedence for such a high profile mine closure program and consequently the many unknowns relating to the mine decommissioning process, legislative requirements and society's expectations resulted in a perception of a significant yet ill-defined liability. In this atmosphere of understandable company, stakeholder and public concern, Rio Algom Limited embarked on what has turned out to be a long, rigorous, challenging yet ultimately reasonable and rewarding process of progressive reclamation of all its Elliot Lake mines, some ten in total (nine uranium, one copper). Over the past ten years, reclamation of all ten mines has been successfully completed, some $70 m plus has been expended in direct site reclamation works and the workforce has been reduced from over 2,500 to just 4. After ten years, the focus of attention is now on the long-term care, maintenance, monitoring and reporting required for the decommissioned mine sites, and the accomplishment of this in the best interests of all the stakeholders. (author)

  19. Electro-remediation of copper mine tailings. Comparing copper removal efficiencies for two tailings of different age

    DEFF Research Database (Denmark)

    Hansen, Henrik K.; Lamas, Victor; Gutierrez, Claudia

    2013-01-01

    This work compares and evaluates the copper removal efficiency when applying electric fields to two mine tailings originating from the same mine but of different age. Eight experiments were carried out - four on tailings deposited more than 20 years ago (old tailings) and four on tailings deposit...

  20. Radon flux from rehabilitated and unrehabilitated uranium mill tailings deposits

    International Nuclear Information System (INIS)

    Sonter, M.; Akber, R.; Holdsworth, S.

    2002-01-01

    Radon release from uranium tailings deposits was identified in UNSCEAR 1993 as the main potential source of collective dose to the world population from the use of nuclear power (rather than, say, gamma doses to power plant workers, or doses to reprocessing plant workers or to waste-handling workers, or residents living adjacent to these facilities). This is due primarily to the ongoing nature of the radon releases over geological time and to the assumption of a 10,000 year integration time. UNSCEAR 1993 estimated 150 person-sieverts per GWe-yr of produced power, based on some very general assumptions about area of tailings per unit of uranium produced, uranium usage per unit of power produced, radon emanation per unit surface area of tails, population density within 100 km of the site, and from 100 km out to 2000 km from the site, and atmospheric dispersion. It should be noted at the outset that the idea of adding vanishingly small doses across the entire world population and integrating for 10,000 years into the future, to obtain a collective dose which is then used to infer induced cancer deaths, is warned against by ICRP, and more strongly disavowed in recent papers by Roger Clarke, as being unrepresentative of any real risk and a recipe for misallocation of resources. These UNSCEAR assumptions and the resulting estimations of collective dose were reviewed by SENES Consultants Ltd of Canada, in a report commissioned by the Uranium Institute, both in terms of the methodology and in terms of the factors used. In this report SENES substituted its best estimate assumptions, based on responses received from major commercial uranium mining operations for UNSCEAR's assumptions, which it identified as highly pessimistic, and arrived at a putative collective dose of about 1 person-sievert/ GWe-yr. The most recent UNSCEAR 2000 report acknowledges the uncertainty in the figures, and references the SENES report as providing more specific (but still limited) data. Taking on

  1. The use of a large-strain consolidation model to optimise multilift tailing deposits

    NARCIS (Netherlands)

    Vardon, P.J.; Yao, Y.; Van Paassen, L.A.; Van Tol, A.F.

    2015-01-01

    Thin-lift atmospheric fine drying (AFD) is a technique used to dewater mine and oil sand tailings, which utilises both self-weight consolidation and atmospheric evaporation. The disposed layers undergo a cyclic drying and rewetting process due to precipitation and deposition of additional lifts on

  2. Geotechnical parameters and behaviour of uranium tailings

    International Nuclear Information System (INIS)

    Matyas, E.L.

    1984-01-01

    The results of laboratory and in situ testing and test blasting, the observations made on a test embankment, and a description of actual construction practice associated with engineering studies for the management of uranium mill tailings at Elliot Lake, Ontario are presented. Relative density values inferred from standard penetration tests and cone penetrometer tests are shown to be inconsistent with relative density values determined from maximum and minimum void ratios. Some of the data contradicts existing correlations. The compressibility of in situ saturated tailings is presented in graphical form in terms of void ratio, vertical effective stress, and mean grain size. Hydraulic conductivity is shown to range over many orders of magnitude, depending on the void ratio. The observations on an instrumental test embankment are used to explain the appropriate selection of geotechnical parameters that gave good agreement between back-calculated and observed settlements. One-dimensional consolidation theory was found to be valid for the embankment case. It is necessary to account for changes in soil properties that occur during the consolidation process in order to obtain a good fit between back-calculated and observed settlements. The successful use of tailings sand for embankment construction is described. On the basis of normalized standard penetration resistance values, it is concluded that localized zones of saturated tailings may be prone to liquefaction under predicted earthquake loadings

  3. Impaired Short-Term Functioning of a Benthic Community from a Deep Norwegian Fjord Following Deposition of Mine Tailings and Sediments

    Directory of Open Access Journals (Sweden)

    Lisa Mevenkamp

    2017-05-01

    Full Text Available The extraction of minerals from land-based mines necessitates the disposal of large amounts of mine tailings. Dumping and storage of tailings into the marine environment, such as fjords, is currently being performed without knowing the potential ecological consequences. This study investigated the effect of short-term exposure to different deposition depths of inert iron ore tailings (0.1, 0.5, and 3 cm and dead subsurface sediment (0.5 and 3 cm on a deep water (200 m fjord benthic assemblage in a microcosm experiment. Biotic and abiotic variables were measured to determine structural and functional changes of the benthic community following an 11 and 16 day exposure with tailings and dead sediment, respectively. Structural changes of macrofauna, meiofauna, and bacteria were measured in terms of biomass, density, community composition and mortality while measures of oxygen penetration depth, sediment community oxygen consumption and 13C-uptake and processing by biota revealed changes in the functioning of the system. Burial with mine tailings and natural sediments modified the structure and functioning of the benthic community albeit in a different way. Mine tailings deposition of 0.1 cm and more resulted in a reduced capacity of the benthic community to remineralize fresh 13C-labeled algal material, as evidenced by the reduced sediment community oxygen consumption and uptake rates in all biological compartments. At 3 cm of tailings deposition, it was evident that nematode mortality was higher inside the tailings layer, likely caused by reduced food availability. In contrast, dead sediment addition led to an increase in oxygen consumption and bacterial carbon uptake comparable to control conditions, thereby leaving deeper sediment layers anoxic and in turn causing nematode mortality at 3 cm deposition. This study clearly shows that even small levels (0.1 cm of instantaneous burial by mine tailings may significantly reduce benthic ecosystem

  4. A socially committed literary work: perspectives on Elliot Zondi’s Insumansumane

    Directory of Open Access Journals (Sweden)

    N.N. Mathonsi

    2005-07-01

    Full Text Available In this article Elliot Zondi’s historical drama, “Insumansumane”, is discussed as a committed literary work. The main character, Bhambada, urges his contemporaries to challenge the ideological domination of the apartheid system and to fight for their freedom to the last man, if necessary. According to Elliot Zondi, the 1906 Bhambada Rebellion was caused by a lack of consultation and utter disregard for the feelings of the African majority regarding taxation. The rebellion was also caused by the forceful introduction of Western culture and social values. The play in itself is actually a metaphor for the Zulu people living in the 1980s under the iron rule of President P.W. Botha. In this play the Zulu are urged to live up to the freedom ideals for which their forefathers had been ready to fight and to die. The development of the plot in the play emphasises that the “winds of change” at that time were becoming stronger, causing the undercurrent that was to bring about liberation in 1992 and in 1994.

  5. Uranium tailings reference materials

    International Nuclear Information System (INIS)

    Smith, C.W.; Steger, H.F.; Bowman, W.S.

    1984-01-01

    Samples of uranium tailings from Bancroft and Elliot Lake, Ontario, and from Beaverlodge and Rabbit Lake, Saskatchewan, have been prepared as compositional reference materials at the request of the National Uranium Tailings Research Program. The four samples, UTS-1 to UTS-4, were ground to minus 104 μm, each mixed in one lot and bottled in 200-g units for UTS-1 to UTS-3 and in 100-g units for UTS-4. The materials were tested for homogeneity with respect to uranium by neutron activation analysis and to iron by an acid-decomposition atomic absorption procedure. In a free choice analytical program, 18 laboratories contributed results for one or more of total iron, titanium, aluminum, calcium, barium, uranium, thorium, total sulphur, and sulphate for all four samples, and for nickel and arsenic in UTS-4 only. Based on a statistical analysis of the data, recommended values were assigned to all elements/constituents, except for sulphate in UTS-3 and nickel in UTS-4. The radioactivity of thorium-230, radium-226, lead-210, and polonium-210 in UTS-1 to UTS-4 and of thorium-232, radium-228, and thorium-228 in UTS-1 and UTS-2 was determined in a radioanalytical program composed of eight laboratories. Recommended values for the radioactivities and associated parameters were calculated by a statistical treatment of the results

  6. Enriching acid rock drainage related microbial communities from surface-deposited oil sands tailings.

    Science.gov (United States)

    Dean, Courtney; Xiao, Yeyuan; Roberts, Deborah J

    2016-10-01

    Little is known about the microbial communities native to surface-deposited pyritic oil sands tailings, an environment where acid rock drainage (ARD) could occur. The goal of this study was to enrich sulfur-oxidizing organisms from these tailings and determine whether different populations exist at pH levels 7, 4.5, and 2.5. Using growth-based methods provides model organisms for use in the future to predict potential activities and limitations of these organisms and to develop possible control methods. Thiosulfate-fed enrichment cultures were monitored for approximately 1 year. The results showed that the enrichments at pH 4.5 and 7 were established quicker than at pH 2.5. Different microbial community structures were found among the 3 pH environments. The sulfur-oxidizing microorganisms identified were most closely related to Halothiobacillus neapolitanus, Achromobacter spp., and Curtobacterium spp. While microorganisms related to Chitinophagaceae and Acidocella spp. were identified as the only possible iron-oxidizing and -reducing microbes. These results contribute to the general knowledge of the relatively understudied microbial communities that exist in pyritic oil sands tailings and indicate these communities may have a potential role in ARD generation, which may have implications for future tailings management.

  7. Current expansion of the Elliot Lake mines

    International Nuclear Information System (INIS)

    Stenning, G.

    1982-06-01

    The Elliot Lake mines are located in northern Ontario, on the north shore of Lake Huron. Mining operations in this area started in the mid-1950's and were curtailed during the 1960's. Starting in 1973 Rio Algom's Quirke mine and Denison, the only producers remaining in the area, started to make plans to expand. Increasing production to 30,000 tpd (milled) requires the reopening of the Panel and Stanleigh Mines of the Rio Algom group and the Stanrock-CanMet area at Denison. The first phase of the expansion was preceded by extensive public hearings. Mine production increases, improvement to the facilities at the reopened mines, and the effects on community facilities are described in this paper

  8. Diagnostic analysis of electrodialysis in mine tailing materials

    DEFF Research Database (Denmark)

    Hansen, Henrik K.; Ribeiro, Alexandra B.; Mateus, Eduardo

    2007-01-01

    Removal of heavy metals from mine tailings and soil contaminated by copper mining activities was studied under batch electrodialytic conditions. Two types of mine tailings were treated: (i) freshly produced tailings coming directly from the flotation process, and (ii) tailings deposited...... in a tailings pond, for approximately 20 years. The main contaminant was copper-found in concentration around 800-1800 ppm. The fractionation of copper and other characteristics of the tailings differ for the two tailings, indicating natural oxidation reactions in the old deposited ones. Electrodialytical...

  9. Tailings management at Nabarlek

    International Nuclear Information System (INIS)

    Waggitt, P.

    1989-01-01

    As the entire uranium deposit at Nabarlek was mined in 1979, the mine pit was available as a tailing's repository from the time of commencement of ore processing. In the early years Nabarlek's tailings were deposited subaqueously. In 1985 the tailings deposition method was changed to a sub-aerial, or semi-dry, method. Over the subsequent three years there was evidence that the tailings settled further and squeezed water from lower layers. The water was pumped away and treated for removal of radium before being evaporated in one of the mine's evaporation ponds. When milling was completed in 1988 it was decided to try and increase the rate of water removal and so obtain even greater consolidation of the trailings in a shorter time. This was achieved by loading the tailings with a layer of screened leached sands and waste rock placed on a layer of geotextile filter fabric that had been laid over the whole of the tailings surface in the pit. Once this was completed a modified piling rig was used to insert vertical drains, or wicks, up to 30 metres into the tailings. The drains were placed on a square grid at a spacing of 3.25 metres. Water that was forced out of the tailings by the downward pressure of the sand and rock could flow freely to the surface up these drains. Once at the surface the water was gathered into a sump and pumped away for treatment as before. The drains are working very well at present although it will be some considerable time before the water stops flowing. Already settlement of the tailings is apparent and the settled density of the material is increasing. As far as is known this is the first time that such a system has been employed on mine tailings in a pit in this way

  10. Settlement of uranium mill tailings

    International Nuclear Information System (INIS)

    Chen, P.K.; Guros, F.B.; Keshian, B.

    1988-01-01

    Two test embankments were constructed on top of an old tailings deposit near Ambrosia Lake, New Mexico to determine settlement characteristics of hydraulically- deposited uranium mill tailings. Before construction of the embankments, properties of in-situ tailings and foundation soils were determined using data from boreholes, piezocone soundings, and laboratory tests. These properties were used to estimate post-construction settlement of a planned disposal embankment to be constructed on the tailings. However, excessive uncertainty existed in the following: field settlement rates of saturated and unsaturated tailings, degree of preconsolidation of the upper 15 feet of tailings, and the ability of an underlying silty sand foundation layer to facilitate drainage. Thus, assurance could not be provided that differential settlements of the radon barrier and erosion protection layers would be within allowable limits should the planned disposal embankment be constructed in a single-stage

  11. Expansion of the uranium mines in the Elliot Lake area

    International Nuclear Information System (INIS)

    1979-11-01

    This report forms the response of the government of Ontario to an earlier report issued by an Envrionmental Assessment Board. Specifically, the report deals with the rapid growth of the town of Elliot Lake due to expansion of several uranium mine-mill operations. Rapid growth of small communities presents considerable problems in providing housing, essential services, and educational facilities. Several specific actions taken by the government to help the town cope with rapid growth are presented. (O.T.)

  12. Remediation of a marine shore tailings deposit and the importance of water-rock interaction on element cycling in the coastal aquifer.

    Science.gov (United States)

    Dold, Bernhard; Diaby, Nouhou; Spangenberg, Jorge E

    2011-06-01

    We present the study of the geochemical processes associated with the first successful remediation of a marine shore tailings deposit in a coastal desert environment (Bahía de Ite, in the Atacama Desert of Peru). The remediation approach implemented a wetland on top of the oxidized tailings. The site is characterized by a high hydraulic gradient produced by agricultural irrigation on upstream gravel terraces that pushed river water (∼500 mg/L SO(4)) toward the sea and through the tailings deposit. The geochemical and isotopic (δ(2)H(water) and δ(18)O(water), δ(34)S(sulfate), δ(18)O(sulfate)) approach applied here revealed that evaporite horizons (anhydrite and halite) in the gravel terraces are the source of increased concentrations of SO(4), Cl, and Na up to ∼1500 mg/L in the springs at the base of the gravel terraces. Deeper groundwater interacting with underlying marine sequences increased the concentrations of SO(4), Cl, and Na up to 6000 mg/L and increased the alkalinity up to 923 mg/L CaCO(3) eq. in the coastal aquifer. These waters infiltrated into the tailings deposit at the shelf-tailings interface. Nonremediated tailings had a low-pH oxidation zone (pH 1-4) with significant accumulations of efflorescent salts (10-20 cm thick) at the surface because of upward capillary transport of metal cations in the arid climate. Remediated tailings were characterized by neutral pH and reducing conditions (pH ∼7, Eh ∼100 mV). As a result, most bivalent metals such as Cu, Zn, and Ni had very low concentrations (around 0.01 mg/L or below detection limit) because of reduction and sorption processes. In contrast, these reducing conditions increased the mobility of iron from two sources in this system: (1) The originally Fe(III)-rich oxidation zone, where Fe(III) was reduced during the remediation process and formed an Fe(II) plume, and (2) reductive dissolution of Fe(III) oxides present in the original shelf lithology formed an Fe-Mn plume at 10-m depth. These

  13. Uranium deposit research, 1983

    International Nuclear Information System (INIS)

    Ruzicka, V.; LeCheminant, G.M.

    1984-01-01

    Research on uranium deposits in Canada, conducted as a prerequisite for assessment of the Estimated Additional Resources of uranium, revealed that (a) the uranium-gold association in rudites of the Huronian Supergroup preferably occurs in the carbon layers; (b) chloritized ore at the Panel mine, Elliot Lake, Ontario, occurs locally in tectonically disturbed areas in the vicinity of diabase dykes; (c) mineralization in the Black Sturgeon Lake area, Ontario, formed from solutions in structural and lithological traps; (d) the Cigar Lake deposit, Saskatchewan, has two phases of mineralization: monomineralic and polymetallic; (e) mineralization of the JEB (Canoxy Ltd.) deposit is similar to that at McClean Lake; (f) the uranium-carbon assemblage was identified in the Claude deposit, Carswell Structure; and (g) the Otish Mountains area, Quebec, should be considered as a significant uranium-polymetallic metallogenic province

  14. Recycling and utilisation of industrial solid waste: an explorative study on gold deposit tailings of ductile shear zone type in China.

    Science.gov (United States)

    Liu, Rui; Huang, Fei; Du, Runxiang; Zhao, Chunming; Li, Yongli; Yu, Haoran

    2015-06-01

    Tailings are solid waste arising from mineral processing. This type of waste can cause severe damage to the environment during stockpiling as a result of the leaching of something harmful into the ecosystem. Gold deposit of ductile shear zone type is an important type of gold deposit, and the recycling of its tailings has been challenging researchers for a long time. In this article, the characteristics of this type of tailings were systematically studied by using modern technical means. Considering the characteristics of the tailings, clay was selected to make up for the shortcomings of the tailings and improve their performance. Water and raw materials were mixed to produce green bodies, which are subsequently sintered into ceramic bodies at 980 °C~1020 °C (sintering temperature). The results showed that some new kinds of mineral phases, such as mullite, anorthite and orthoclase, appear in ceramic bodies. Furthermore, the ceramic bodies have a surface hardness of 5 to 6 (Mohs scale), and their water absorption and modulus of rupture can meet some technical requirements of ceramic materials described in ISO 13006-2012 and GB 5001-1985. These gold mine tailings can be made into ceramic tiles, domestic ceramic bodies, and other kinds of ceramic bodies for commercial and industrial purposes after further improvements. © The Author(s) 2015.

  15. Utilization of mine tailings as partial cement replacement

    DEFF Research Database (Denmark)

    Sigvardsen, Nina Marie; Nielsen, M.R.; Ottosen, Lisbeth M.

    2017-01-01

    Depositing mine tailings entail major economic costs and negative environmental impacts. Thus finding an alternative to depositing is of interest. This study focused on the use of mine tailings as partial cement replacement, thereby preventing depositing the mine tailings. At the same time......, such use would reduce the CO2 emission related to the production of cement. Mine tailings from two different mines Zinkgruvan (Sweden) and Nalunaq (Greenland) were both tested as 5 and 10 % cement replacement. All mortar specimens with mine tailings had lower compressive strength compared to a reference...... compared to a specimen containing a 10 % replacement of cement with coal fly ash, commonly used in Denmark. The compressive strength of specimens containing mine tailings exceeded the compressive strength of the specimen containing coal fly ash, indicating further the amorphous content of volcanic decent...

  16. Laboratory dust generation and size-dependent characterization of metal and metalloid-contaminated mine tailings deposits

    Energy Technology Data Exchange (ETDEWEB)

    Gonzales, Patricia; Felix, Omar [Department of Chemical and Environmental Engineering, University of Arizona, 1133 E. James E. Rogers Way, Tucson, AZ 85721 (United States); Alexander, Caitlin; Lutz, Eric [Division of Community, Environment, and Policy, Mel and Enid Zuckerman College of Public Health, University of Arizona, 1656 E. Mabel St., Tucson, AZ 85724 (United States); Ela, Wendell [Department of Chemical and Environmental Engineering, University of Arizona, 1133 E. James E. Rogers Way, Tucson, AZ 85721 (United States); Eduardo Sáez, A., E-mail: esaez@arizona.edu [Department of Chemical and Environmental Engineering, University of Arizona, 1133 E. James E. Rogers Way, Tucson, AZ 85721 (United States)

    2014-09-15

    Highlights: • A laboratory dust fractionator was developed for the production of respirable dust. • The size-dependent distribution of arsenic and lead in mine tailings dust is reported. • Metal and metalloid contaminants are enriched in particles smaller than 10 μm. • Lead isotope signatures show spread of mine tailings particles onto surrounding soils. - Abstract: The particle size distribution of mine tailings material has a major impact on the atmospheric transport of metal and metalloid contaminants by dust. Implications to human health should be assessed through a holistic size-resolved characterization involving multidisciplinary research, which requires large uniform samples of dust that are difficult to collect using conventional atmospheric sampling instruments. To address this limitation, we designed a laboratory dust generation and fractionation system capable of producing several grams of dust from bulk materials. The equipment was utilized in the characterization of tailings deposits from the arsenic and lead-contaminated Iron King Superfund site in Dewey-Humboldt, Arizona. Results show that metal and metalloid contaminants are more concentrated in particles of <10 μm aerodynamic diameter, which are likely to affect surrounding communities and ecosystems. In addition, we traced the transport of contaminated particles from the tailings to surrounding soils by identifying Pb and Sr isotopic signatures in soil samples. The equipment and methods developed for this assessment ensure uniform samples for further multidisciplinary studies, thus providing a tool for comprehensive representation of emission sources and associated risks of exposure.

  17. Laboratory dust generation and size-dependent characterization of metal and metalloid-contaminated mine tailings deposits

    International Nuclear Information System (INIS)

    Gonzales, Patricia; Felix, Omar; Alexander, Caitlin; Lutz, Eric; Ela, Wendell; Eduardo Sáez, A.

    2014-01-01

    Highlights: • A laboratory dust fractionator was developed for the production of respirable dust. • The size-dependent distribution of arsenic and lead in mine tailings dust is reported. • Metal and metalloid contaminants are enriched in particles smaller than 10 μm. • Lead isotope signatures show spread of mine tailings particles onto surrounding soils. - Abstract: The particle size distribution of mine tailings material has a major impact on the atmospheric transport of metal and metalloid contaminants by dust. Implications to human health should be assessed through a holistic size-resolved characterization involving multidisciplinary research, which requires large uniform samples of dust that are difficult to collect using conventional atmospheric sampling instruments. To address this limitation, we designed a laboratory dust generation and fractionation system capable of producing several grams of dust from bulk materials. The equipment was utilized in the characterization of tailings deposits from the arsenic and lead-contaminated Iron King Superfund site in Dewey-Humboldt, Arizona. Results show that metal and metalloid contaminants are more concentrated in particles of <10 μm aerodynamic diameter, which are likely to affect surrounding communities and ecosystems. In addition, we traced the transport of contaminated particles from the tailings to surrounding soils by identifying Pb and Sr isotopic signatures in soil samples. The equipment and methods developed for this assessment ensure uniform samples for further multidisciplinary studies, thus providing a tool for comprehensive representation of emission sources and associated risks of exposure

  18. Past, present and future of dust research at the Elliot Lake Laboratory

    International Nuclear Information System (INIS)

    Grenier, M.; Bigu, J.

    1985-12-01

    A brief history of the dust research work at the Elliot Lake Laboratory is given. Two decades of dust research work are studied and reviewed. This review clearly shows where, when, and with what intensity various components of dust research were performed. From the data presented here, it is suggested that a major portion of the future efforts be aimed at research directed towards the control and suppression of dust in underground mines

  19. Shrinkage and swelling properties of flocculated mature fine tailings

    NARCIS (Netherlands)

    Yao, Y.; Van Tol, A.F.; Van Paassen, L.A.; Vardon, P.J.

    2014-01-01

    In the atmospheric fines drying technique, mature fine tailings (MFT) are treated with polymers and deposited in thin layers on a sloped surface for sub-aerial drying. During the whole drying period, the tailings deposits can experience rewetting during periods of rainy weather or as result of the

  20. APPLICATION OF POSTFLOTATION TAILINGS IN HYDROENGINEERING STRUCTURES

    Directory of Open Access Journals (Sweden)

    Katarzyna Stefaniak

    2017-01-01

    Full Text Available Economic development stimulated by the increased demand for production of consumer goods and the growing human population result in increasing amounts of various wastes, including tailings. The mining industry in Poland, comprising also mining of non-ferrous metal ores, is a strategic branch of the national economy and at the same time a leading waste producer. Tailings management is a significant problem both in Poland and worldwide. Frequently considerable amounts of wastes are accumulated in mine spoil tips, in areas not always suitable for their deposition, thus leading to the degradation of the surrounding environment. At the huge volume of produced wastes their rational and economically viable management is becoming crucial. On the other hand, depletion of natural aggregate deposits is an important incentive to search for substitutes, which would be suitable for the development of road infrastructure or which could be used in earth structure engineering to construct hydroengineering objects. Since no profitable recovery technologies are available at present, tailings generated by copper mining are deposited in tailings storage facilities. The largest and at the same time the only currently operating facility in Poland is the Żelazny Most Mining Tailings Storage Facility, belonging to KGHM Polska Miedź S.A. The paper presents criteria for material quality and density imposed on the material embedded in the static core of the tailings pond dam. For this purpose studies were conducted to confirm applicability of sorted tailings as a material for the construction of earth structures.

  1. Observations on stake holder confidence related to uranium mine waste management in the elliot lake region

    International Nuclear Information System (INIS)

    MacDonald, G.

    2003-01-01

    G. MacDonald, representing the Township of the North Shore and the Standing Environmental Committee (SEC) of the Serpent River Watershed, stated that she is a stakeholder living downstream from 175 million tonnes of acid-generating and radioactive uranium mine tailings. Public confidence in the Elliot Lake region is influenced by past mining issues: worker health concerns and difficulties in obtaining compensation; myriad observations of radium uptake; drinking water contamination issues and inequitable quality standards adverse to the Serpent River First Nation; loss of land use. Government failed to set aside funds for local monitoring of the decommissioned mining region, or to involve citizens in decisions as recommended by the Kirkwood Panel. These failures represent betrayals of trust and furthermore give public confidence little chance to improve. In these circumstances, the affected community has given attention on their own to mid- and long-term issues. At issue is not the current funding or management of the waste storage sites, but rather, creating and maintaining local knowledge and competence to monitor their management over the coming decades and generations. Concerned members of the community note that the federal government 'has done nothing long-lasting to ensure confidence', on this level. They highlight the importance of questions like: 'Do I have the knowledge to act in my best interest?' and 'Who can I trust to protect my interest?' - and have set out to answer them. (author)

  2. Blast densification trials for oilsands tailings

    Energy Technology Data Exchange (ETDEWEB)

    Port, A. [Klohn Crippen Berger Ltd., Vancouver, BC (Canada); Martens, S. [Klohn Crippen Berger Ltd., Calgary, AB (Canada); Eaton, T. [Shell Canada Ltd., Calgary, AB (Canada)

    2010-07-01

    The Shell Canada Muskeg River Mine External Tailings Facility (ETF) is an upstream constructed tailings facility located near Fort McMurray, Alberta. Raises have incrementally stepped out over the beach since construction of the starter dam and deposition within standing water has left some parts of the beach in a loose state. In order to assess the effectiveness of blast densification, a blast densification trial program that was conducted in 2006 at the ETF. The primary purpose of the test program was to determine the effectiveness of blast densification in tailings containing layers and zones of bitumen. The paper described the site characterization and explosive compaction trial program, with particular reference to test layout; drilling methodology; and blasting and timing sequence. The paper also described the instrumentation, including the seismographs; high pressure electric piezometers; low pressure electric piezometers; vibrating wire piezometers; inclinometers; settlement gauges; and surveys. Trial observations and post-trial observations were also presented. It was concluded that controlled blasting techniques could be used to safely induce liquefaction in localized areas within the tailings deposit, with a resulting increase in the tailings density. 5 refs., 1 tab., 14 figs.

  3. Heavy mineral concentration from oil sand tailings

    Energy Technology Data Exchange (ETDEWEB)

    Chachula, F.; Erasmus, N. [Titanium Corp. Inc., Regina, SK (Canada)

    2008-07-01

    This presentation described a unique technique to recover heavy minerals contained in the froth treatment tailings produced by oil sand mining extraction operations in Fort McMurray, Alberta. In an effort to process waste material into valuable products, Titanium Corporation is developing technology to recover heavy minerals, primarily zircon, and a portion of bitumen contained in the final stage of bitumen processing. The process technology is being developed to apply to all mined oil sands operations in the Fort McMurray region. In 2004, Titanium Corporation commissioned a pilot research facility at the Saskatchewan Research Council to test dry oil sands tailings. In 2005, a bulk sampling pilot plant was connected to the fresh oil sands tailings pipeline on-site in Fort McMurray, where washed sands containing heavy minerals were processed at a pilot facility. The mineral content in both deposited tailings and fresh pipeline tailings was assessed. Analysis of fresh tailings on a daily basis identified a constant proportion of zircon and higher levels of associated bitumen compared with the material in the deposited tailings. The process flow sheet design was then modified to remove bitumen from the heavy minerals and concentrate the minerals. A newly modified flotation process was shown to be a viable processing route to recover the heavy minerals from froth treatment tailings. 8 refs., 9 tabs., 12 figs.

  4. Uranium and thorium deposits of Northern Ontario

    International Nuclear Information System (INIS)

    Robertson, J.A.; Gould, K.L.

    1983-01-01

    This, the second edition of the uranium-thorium deposit inventory, describes briefly the deposits of uranium and/or thorium in northern Ontario, which for the purposes of this circular is defined as that part of Ontario lying north and west of the Grenville Front. The most significant of the deposits described are fossil placers lying at or near the base of the Middle Precambrian Huronian Supergroup. These include the producing and past-producing mines of the Elliot Lake - Agnew Lake area. Also included are the pitchblende veins spatially associated with Late Precambrian (Keweenawan) diabase dikes of the Theano Point - Montreal River area. Miscellaneous Early Precambrian pegmatite, pitchblende-coffinite-sulphide occurrences near the Middle-Early Precambrian unconformity fringing the Lake Superior basin, and disseminations in diabase, granitic rocks, alkalic complexes and breccias scattered throughout northern Ontario make up the rest of the occurrences

  5. The uranium deposits of Ontario

    International Nuclear Information System (INIS)

    Robertson, J.A.

    1981-01-01

    The principal types of uranium deposits in Ontario are carbonatites and fenites, alkalic volcanic rocks, pegiatites, calc-silicate rocks, pyritic quartz-pebble conglomerates, polymictic conglomerates and some pelitic rocks, and various 'pitchblende' deposits including late Precambrian unconformities, possibly late Precambrian diabase dikes, and other unconformities: carbonates, sandstones, lignites, and semi-pelitic rocks of middle and upper Precambrian age. Only red unzoned pegmatite and the pyritic quartz-pebble conglomerate have supported production. Ontario reasonably assured and estimated resources in the economic and subeconomic categories in 1977 amounted to 553 000 tonnes U, and 1977 production was 4000 tonnes U. Measured, indicated, and inferred resources in the Elliot Lake - Agnew Lake area are at least 400 000 tonnes U. The latter deposits are also a significant thorium resource. Geological features reflecting major changes in physics and chemistry are prime controls on distribution of uranium deposits. Geological province and subprovince boundaries, major faults, higher metamorphic grades, domain boundaries related to quartz monzonite batholiths, alkalic complexes, and the distribution of carbonate rocks are examples of such geological features

  6. Cameco engineered tailings program: linking research with industrial processes for improved tailings performance

    International Nuclear Information System (INIS)

    Kotzer, T.; Hendry, M.J.

    2011-01-01

    The waste product from uranium mining and milling that generates the greatest public and regulatory concern is tailings. The tailings contain all of the mined material except uranium plus a host of processing reagents. These minerals and compounds have the potential to harm the local environment if not deposited in a fashion that is both geochemically and geotechnically stable. Environmental leadership impels Cameco Corporation to ensure that the methods used to dispose of tailings are at the forefront of best available technologies whereby tailings production results in a product with geotechnical and geochemical characteristics that minimize the environmental impact associated with long-term storage of this product. Cameco has developed an Engineered Tailings (ET) program to ensure optimization of long-term tailings performance and minimal impacts of elements of concern (EOCs) to the receiving environment, regardless of the ore being milled. Within this program chemical and physical performance of tailings from geochemical and geotechnical investigations and baseline environmental data, integrated with regulatory requirements and corporate commitments, will be used to evaluate and set criteria for mill- and tailings management facilities-based chemical and physical tailings characteristics, identify key knowledge gaps, prioritize areas of concern and implement appropriate responses. This paper provides an overview of the Engineered Tailings program, the research being conducted as part of the ET program, and how it links with present and future Cameco operations. (author)

  7. Evaluation of respirable particle matter in gold mine tailings on the Witwatersrand

    International Nuclear Information System (INIS)

    Ojelede, M.E.; Annegarn, H.J.

    2007-01-01

    Within the Witwatersrand gold mining area of South Africa, wind-blown dust is a significant contributor to atmospheric air pollution brought to the fore with the reworking of old mine tailings. Approximately 40,000 hectares are covered with tailings in the Witwatersrand. Wind-erosion during late austral winter and early spring causes surfaces of these tailings to be exposed, particularly during higher wind speeds and in the absence of rainfall. Local residents complain as the surrounding areas experience unpleasant dust episodes. As a result of urban PM 10 and PM 2.5 respirable particulate matter, increased respiratory ailments, morbidity and mortality, and concerns about the health impacts of wind-blown mine tailings in South Africa have been reported. Since 1981, significant monitoring of dustfall has taken place on the Witwatersrand, however, characterization of the respirable fraction of gold mine tailings material and dustfall is lacking. This paper presented the results of a study that established the content of respirable particulate matter in exposed mine tailings and wind-blown dust, and their likely contributions to ambient air. The initial results of the particulate size distribution of material samples from tailings and dust deposits collected in ambient dustfall-monitors were provided. Particle size distributions from different deposit types include slimes and sand deposits, surface and core material, and wind-winnowed secondary deposits. Fractions of PM 10 in source and deposited material were also discussed. It was concluded that there was a significant fraction of PM 10 material in the mine tailings, and that further work to quantify the population exposure risk is needed. 11 refs., 1 tab., 6 figs

  8. Microbial weathering processes after release of heavy metals and arsenic from fluvial tailing deposits; Mikrobielle Verwitterungsprozesse bei der Freisetzung von Schwermetallen und Arsen aus fluvialen Tailingablagerungen

    Energy Technology Data Exchange (ETDEWEB)

    Willscher, S. [Technische Univ. Dresden (Germany). Fak. fuer Forst, Geo und Hydrowissenschaften, Inst. fuer Abfallwirtschaft und Altlasten

    2006-07-01

    Microbial processes play an important role in global metal cycles. The microbial weathering of mineral surfaces, including deposited anthropogenic mineral remainders, is a natural occurring process, taking place on uncovered dump surfaces as well as in deeper zones of dumps. Such weathering processes also occur in metal contaminated soils and sediments. In this work, a sulfidic fluvial tailing sediment was investigated for its acidity and salinity generating potential and the subsequent mobilisation of heavy metals, generated by biogeochemical processes. The long-term risks of such a deposit were evaluated. Unstabilised deposits of such materials can generate a considerable contamination of the surrounding ground and surface water. It could be shown in the experiments that in acid generating dumps and tailing materials besides the well known acidophilic autotrophs also acidotolerant heterotrophic microorganisms play a role in the mobilisation of metals. (orig.)

  9. Modelling of contaminant migration in acidic groundwater plumes at uranium tailings impoundments: ADNEUT3

    International Nuclear Information System (INIS)

    Cherry, J.A.; Morin, K.A.; Dubrovsky, N.M.

    1984-06-01

    This report describes the creation and application of ADNEUT3, the latest addition to the ADNEUT (Acid-Drainage NEUTralization) family of computer programs for simulating acid-drainage transport and neutralization. The creation of ADNEUT3 involved the expansion of ADNEUT1 to allow variable input conditions such as changing input solution with time, variable initial amounts of minerals through the simulated streamtube, variable velocities through the streamtube, and variable solubilities for relevant minerals dependent on aqueous chemical composition. Concepts for simulating acid-drainage neutralization are reviewed and ADNEUT3 is then applied to a field-study site of acidic contaminant migration from the Nordic Main uranium-tailings impoundment near Elliot Lake, Ontario. A sensitivity study is first implemented to calibrate ADNEUT3 to the results of the 1979 to 1983 field studies. Then ADNEUT3 is used to define probable past conditions at the site which are not reliably known. In particular, ADNEUT3 is used to help identify: 1) the approximate year when acidic seepage began leaving the tailings impoundment (1966-1967), 2) the past chemical composition of the seepage (somewhat more acidic for a short period of time), and 3) the location of the source area within the tailings for the acidic seepage (near the impoundment dam, close to the field site). Finally, ADNEUT3 is used to predict future contaminant migration. Results indicate that hundreds of years are required under present conditions for the most acidic water with associated high levels of contaminants to migrate about 100 m from the tailings impoundment. The cause of this slow movement is the significant neutralization capacity of the aquifer. If acid production within the tailings decreases in the future, migration rates of contaminants will also decrease

  10. Reclamation of copper mine tailings using sewage sludge

    OpenAIRE

    Stjernman Forsberg, Lovisa

    2008-01-01

    Tailings are the fine-grained fraction of waste produced during mining operations. This work was carried out on tailings from the Aitik copper mine in northern Sweden. Establishment of vegetation on the Aitik mine tailings deposit is planned to take place at closure of the mine, using sewage sludge as fertiliser. However, the tailings contain traces of metal sulphides, e.g. pyrite, FeS2, and chalcopyrite, CuFeS2. When the sulphides are oxidised, they start to weather and release metals and st...

  11. Numerical modeling of cracking pattern's influence on the dynamic response of thickened tailings disposals: a periodic approach

    Science.gov (United States)

    Ferrer, Gabriel; Sáez, Esteban; Ledezma, Christian

    2018-01-01

    Copper production is an essential component of the Chilean economy. During the extraction process of copper, large quantities of waste materials (tailings) are produced, which are typically stored in large tailing ponds. Thickened Tailings Disposal (TTD) is an alternative to conventional tailings ponds. In TTD, a considerable amount of water is extracted from the tailings before their deposition. Once a thickened tailings layer is deposited, it loses water and it shrinks, forming a relatively regular structure of tailings blocks with vertical cracks in between, which are then filled up with "fresh" tailings once the new upper layer is deposited. The dynamic response of a representative column of this complex structure made out of tailings blocks with softer material in between was analyzed using a periodic half-space finite element model. The tailings' behavior was modeled using an elasto-plastic multi-yielding constitutive model, and Chilean earthquake records were used for the seismic analyses. Special attention was given to the liquefaction potential evaluation of TTD.

  12. Determination of the reaction rate coefficient of sulphide mine tailings deposited under water.

    Science.gov (United States)

    Awoh, Akué Sylvette; Mbonimpa, Mamert; Bussière, Bruno

    2013-10-15

    The efficiency of a water cover to limit dissolved oxygen (DO) availability to underlying acid-generating mine tailings can be assessed by calculating the DO flux at the tailings-water interface. Fick's equations, which are generally used to calculate this flux, require knowing the effective DO diffusion coefficient (Dw) and the reaction (consumption) rate coefficient (Kr) of the tailings, or the DO concentration profile. Whereas Dw can be accurately estimated, few studies have measured the parameter Kr for submerged sulphide tailings. The objective of this study was to determine Kr for underwater sulphide tailings in a laboratory experiment. Samples of sulphide mine tailings (an approximately 6 cm layer) were placed in a cell under a water cover (approximately 2 cm) maintained at constant DO concentration. Two tailings were studied: TA1 with high sulphide content (83% pyrite) and TA2 with low sulphide content (2.8% pyrite). DO concentration was measured with a microelectrode at various depths above and below the tailings-water interface at 1 mm intervals. Results indicate that steady-state condition was rapidly attained. As expected, a diffusive boundary layer (DBL) was observed in all cases. An iterative back-calculation process using the numerical code POLLUTEv6 and taking the DBL into account provided the Kr values used to match calculated and experimental concentration profiles. Kr obtained for tailings TA1 and TA2 was about 80 d(-1) and 6.5 d(-1), respectively. For comparison purposes, Kr obtained from cell tests on tailings TA1 was lower than Kr calculated from the sulphate production rate obtained from shake-flask tests. Steady-state DO flux at the water-tailings interface was then calculated with POLLUTEv6 using tailings characteristics Dw and Kr. For the tested conditions, DO flux ranged from 608 to 758 mg O2/m(2)/d for tailings TA1 and from 177 to 221 mg O2/m(2)/d for tailings TA2. The impact of placing a protective layer of inert material over

  13. Men of Good Will: The Religious Education Association, J. Elliot Ross, and the National Conference of Jews and Christians

    Science.gov (United States)

    Nolan, Lucinda A.

    2009-01-01

    An impetus of the Religious Education Association (REA) toward becoming an actively intercultural and interreligious agency emerged in the third decade of its existence. This article explores this period through an examination of the involvement of the REA members, Father John Elliot Ross and others (1884-1946) in a series of seminars conducted by…

  14. Review of fugitive dust control for uranium mill tailings

    International Nuclear Information System (INIS)

    Li, C.T.; Elmore, M.R.; Hartley, J.N.

    1983-01-01

    An immediate concern associated with the disposal of uranium mill tailings is that wind erosion of the tailings from an impoundment area will subsequently deposit tailings on surrounding areas. Pacific Northwest Laboratory (PNL), under contract to the U.S. Nuclear Regulatory Commission, is investigating the current technology for fugitive dust control. Different methods of fugitive dust control, including chemical, physical, and vegetative, have been used or tested on mill tailings piles. This report presents the results of a literature review and discussions with manufacturers and users of available stabilization materials and techniques

  15. Review of fugitive dust control for uranium mill tailings

    Energy Technology Data Exchange (ETDEWEB)

    Li, C.T.; Elmore, M.R.; Hartley, J.N.

    1983-01-01

    An immediate concern associated with the disposal of uranium mill tailings is that wind erosion of the tailings from an impoundment area will subsequently deposit tailings on surrounding areas. Pacific Northwest Laboratory (PNL), under contract to the U.S. Nuclear Regulatory Commission, is investigating the current technology for fugitive dust control. Different methods of fugitive dust control, including chemical, physical, and vegetative, have been used or tested on mill tailings piles. This report presents the results of a literature review and discussions with manufacturers and users of available stabilization materials and techniques.

  16. Design guidelines for multi-seam mining at Elliot Lake

    International Nuclear Information System (INIS)

    Hedley, D.G.F.

    1978-04-01

    With the current expansion in uranium mining, multi-seam mining could again be practised at Elliot Lake as it was in the 1960s. Information on the dimensions of stopes, pillars, and parting zone was gathered from plans and sections of the relevant closed mines. Discussions were held with personnel familiar with these mines to establish instances of pillar, roof, and parting zone failures. Design guidelines are formulated for stope and pillar dimensions in multi-seam mining for a range of orebody configurations using past practice in a back-analysis approach. Constraints imposed by dip and seam thickness on the choice of equipment and mining layout are evaluated. An attempt is made to bring together the engineering aspects, including rock mechanics, of multi-seam mine design with uranium recovery and other economic factors for three alternative mine layouts: single-seam mining, double-seam mining, and seams-and-parting mining. A series of examples are worked through, showing how the design guidelines can be applied for typical orebody configurations

  17. Mud-farming of fine oil sands tailings

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Y.; Tol van, F.; Paassen van, L.; Everts, B.; Mulder, A. [Delft Univ. of Technology, Delft (Netherlands). Dept. of Geotechnology

    2010-07-01

    This PowerPoint presentation discussed an experimental mud-farming technique for fine oil sands tailings. The technique was based on a sub-areal drying technique for dredging sludge developed in the Netherlands for Rotterdam harbour sediments. Between 1960 and 1985, the sludge was deposited in confined disposal sites on land. The sludge was converted to usable clay between 1970 and 1980. The polluted portion of the sludge is stored in a man-made disposal site. The sludge was deposited in thin layers. Stagnant water was then removed. The mud was then dewatered and reused. The sludge was furrowed with amphirol and disc wheels in order to accelerate the ripening process. The dredged material was re-used in a clay factory. The technique was applied to oil sands tailings in order to understand the suction behaviour, sedimentation behaviour, and precipitation deficit of the tailings. State changes of the sludge were monitored. No clear sedimentation phase was identified prior to consolidation. A comparison of material properties showed that the total amount of water to be extracted was more than the Rotterdam sludge, but the suction behaviour was similar. The precipitation deficit from mid-April until September will require a customized deposition strategy. Details and photographs of the experimental studies were included. tabs., figs.

  18. Centrifuge - dewatering of oil sand fluid tailings: phase 2 field-scale test

    Energy Technology Data Exchange (ETDEWEB)

    Seto, Jack T.C. [BGC Engineering Inc (Canada); O' Kane, Mike [O' Kane Consultants Inc (Canada); Donahue, Robert [Applied Geochemical Solutions Engineering (Canada); Lahaie, Rick [Syncrude Canada Ltd (Canada)

    2011-07-01

    In order to reduce the accumulation of oil sand fluid fine tailings (FFT) and to create trafficable surfaces for reclamation, Syncrude Canada Ltd. has been studying several tailings technologies. Centrifuge-dewatering is one such technology. This paper discusses the phase 2 field-scale tests for centrifuge-dewatering of oil sand FFT. In centrifuge-dewatering, FFT is diluted and treated with flocculant, then processed through a centrifuge plant and the high-density underflow is transported to a tailings deposit. This technology has evolved since 2005 from laboratory bench scale tests. More than 10,000 cubic meters of centrifuge cake was treated, produced and transported to ten different deposits over a 12-week period from August to October 2010. The amount of solids in FFT was increased from 30% to 50% by centrifuging. Sampled deposits were tested and instrumented for in situ strength. It can be concluded that the deposits can be strengthened and densified by natural dewatering processes like freeze-thaw action and evaporative drying.

  19. Hg in snow cover and snowmelt waters in high-sulfide tailing regions (Ursk tailing dump site, Kemerovo region, Russia).

    Science.gov (United States)

    Gustaytis, M A; Myagkaya, I N; Chumbaev, A S

    2018-07-01

    Gold-bearing polymetallic Cu-Zn deposits of sulphur-pyrite ores were discovered in the Novo-Ursk region in the 1930s. The average content of mercury (Hg) was approximately 120 μg/g at the time. A comprehensive study of Hg distribution in waste of metal ore enrichment industry was carried out in the cold season on the tailing dump site and in adjacent areas. Mercury concentration in among snow particulate, dissolved and colloid fractions was determined. The maximal Hg content in particulate fraction from the waste tailing site ranged 230-573 μg/g. Such indices as the frequency of aerosol dust deposition events per units of time and area, enrichment factor and the total load allowed to establish that the territory of the tailing waste dump site had a snow cover highly contaminated with dust deposited at a rate of 247-480 mg/(m 2 ∙day). Adjacent areas could be considered as area with low Hg contamination rate with average deposition rate of 30 mg/(m 2 ∙day). The elemental composition of the aerosol dust depositions was determined as well, which allowed to reveal the extent of enrichment waste dispersion throughout adjacent areas. The amount of Hg entering environment with snowmelt water discharge was estimated. As a result of snowmelting, in 2014 the nearest to the dump site hydrographic network got Hg as 7.1 g with colloids and as 5880 g as particles. The results obtained allowed to assess the degree of Hg contamination of areas under the impact of metal enrichment industry. Copyright © 2018 Elsevier Ltd. All rights reserved.

  20. Mobility of Ra-226 and Heavy Metals (U, Th and Pb) from Pyritic Uranium Mine Tailings under Sub-aqueous Disposal Conditions - 59283

    International Nuclear Information System (INIS)

    Dave, Nand K.

    2012-01-01

    All uranium mines in the Elliot Lake uranium mining district of north-central Ontario, Canada, have been closed due to low ore grade and prevailing market conditions. A majority of the waste management facilities have been rehabilitated and decommissioned with in-situ shallow water covers to minimize sulphide oxidation, and hence acid generation and release of metal enriched effluents. Laboratory lysimeter studies were undertaken to evaluate the leaching characteristics and mobility of Ra-226 and other heavy metals (U, Th and Pb) from pyritic uranium mine tailings under sub-aqueous disposal conditions for assessing the long-term radiological stability of such waste repositories. The experiments were conducted using three types of un-oxidized tailings: fine, coarse and gypsum depleted mill total tailings. Shallow water covers of depth ∼ 0.3 m were established using natural lake water. The leaching characteristics of radium and other major and trace metals were determined by monitoring both surface and pore water qualities as a function of time. The results showed that Ra-226 was leached from surface of the submerged tailings and released to both surface water and shallow zone pore water during initial low sulphate ion concentration of the surface water cover in all three cases. The release of Ra-226 was further enhanced with the onset of weak acidic conditions in the surface water covers of both coarse and gypsum depleted mill total tailings. With additional acid generation and increasing sulphate and iron concentrations, the dissolved Ra-226 concentrations in the water covers of these tailings gradually decreased back to low levels. Pb was also leached and mobilized with the development of moderate acidic conditions at the surface of the submerged coarse and gypsum deplete tailings. No leaching of U and Th was observed. (authors)

  1. Riparian shrub metal concentrations and growth in amended fluvial mine tailings

    Science.gov (United States)

    Fluvial mine tailing deposition has caused extensive riparian damage throughout the western United States. Willows are often used for fluvial mine tailing revegetation, but some species accumulate excessive metal concentrations which could be detrimental to browsers. In a greenhouse experiment, gr...

  2. Understanding AL-PAM assisted oil sands tailings treatment

    Energy Technology Data Exchange (ETDEWEB)

    Guo, L.; Maham, Y.; Masliyah, J.; Xu, Z. [Alberta Univ., Edmonton, AB (Canada). Dept. of Chemical and Materials Engineering

    2010-07-01

    Technologies currently used to treat oil sands tailings include the composite tailings (CT) process and the thickened tailings (TT) or paste technology process. This PowerPoint presentation discussed a flocculation and filtration method used to produce stackable tailings deposits. Magnafloc 1011 and AL-PAM additions were used as part of the filtration technique to produce very dry filter cakes. The effect of AL-PAM molecular weight and aluminum content on tailings treatments was investigated as well as the effect of tailings characteristics on the performance of flocculant-assisted tailings filtration processes. The AL-PAM molecular structure was studied. An experimental study was conducted to determine the effect of various polymer additions on fresh tailings from an oil sands plant. The study showed that the optimum dosage for settling and filtration was lower for higher molecular weight AL-PAM. A higher aluminum content was beneficial for settling. Increases in the aluminum content did not improve filtration rates, but reduced optimal dosages. Step-by-step details of the supernatant filtration process were provided, as well as photographs of the laboratory study. tabs., figs.

  3. Mill tailings based composites as paste backfill in mines of U-bearing dolomitic limestone ore

    Directory of Open Access Journals (Sweden)

    Sandeep Panchal

    2018-04-01

    Full Text Available This paper elaborates on the development of paste backfill using mill tailings generated during the processing of a uranium ore deposit hosted in dolomitic limestone. The tailings have been characterized in terms of the physical, chemical and mineralogical properties. Time-dependent rheological behaviors and geotechnical properties of cemented paste backfill (CPB are also determined. The studies show that the mill tailing has the potential to form paste and the CPB has adequate strength to provide support to mine pillars, roofs, and walls. Keywords: Mining engineering, Uranium ore deposit, Tailings, Cemented paste backfill (CPB, Rheology, Compressive strength

  4. Waste management implications of concentrating slimes - characteristics and potential problems

    International Nuclear Information System (INIS)

    1986-05-01

    This report describes the geotechnical, geochemical and environmental characteristics of fine-grained uranium tailings (slimes) which may influence both short- and long-term management of slime-enriched uranium tailings impoundments. Properties of slimes are compared and contrasted with those of sand tailings using field and laboratory data primarily from naturally segregated tailings in the Elliot Lake area, Ontario and Northern Saskatchewan uranium-bearing regions of Canada. Key management considerations are included

  5. Further study on source parameters at Quirke Mine, Elliot Lake, Ontario

    International Nuclear Information System (INIS)

    Chen, S.

    1991-01-01

    A further analysis on source parameters for thirty-seven mining-induced seismic events at Quirke Mine, Elliot Lake, Ontario, has been carried out to study the self-similarity assumption in scaling law of seismic spectrum for mining-induced microearthquakes, and to understand the focal mechanism in the mine. Evidence from high P-wave energy in a ratio E p /E s of 5% to 30%, and about 80% of the events with E s /E p L ). For the same total seismic energy, the apparent stress is limited by 80 GN.m and 800 GN.m of seismic moment. The observed stress drop is dependent on the seismic moment, which implies a breakdown in scaling law for events induced by mining. An analysis of peak particle velocity and acceleration presents the evidence for seismic attenuation over the fractured zone above the rock burst area in the mine

  6. Predicting development of undrained shear strength in soft oil sands tailings

    Energy Technology Data Exchange (ETDEWEB)

    Masala, S. [Klohn Crippen Berger, Calgary, AB (Canada); Matthews, J. [Shell Canada Ltd., Calgary, AB (Canada)

    2010-07-01

    This PowerPoint presentation discussed a method of predicting the development of undrained shear strength in soft oil sands tailings. Phenomenology charts of oil sands tailings ponds were used to present the suspension, density, stresses and hydrostatic behaviour of tailings. Sedimentation and consolidation processes were discussed. The charts demonstrated how the tailings slurry settles and consolidates, releases water and dissipates pore pressures. The slurry then develops intergranular stresses and increases in density. The increases correlate with increased resistance to deformation and decreased compressibility and hydraulic conductivity. A critical state soil mechanics (CSSM) was used to characterize the soft oil sands tailings. Undrained strength was determined using the concept of the undrained strength ratio (USR). The USR was determined using traditional geotechnical investigation methods. Settling of the non-consolidated (NC) soil deposits was simulated using the finite strain consolidation theory. The model was based on the premise that current effective stresses control undrained shear strength in the NC deposits. Case studies were used to demonstrate the predictive framework. tabs, figs.

  7. Surficial origin of North American pitchblende and related uranium deposits

    International Nuclear Information System (INIS)

    Langford, F.F.

    1977-01-01

    The ubiquitous association of pitchblende uranium deposits with terrestrial sediments is believed to be the natural result of formation of the orebodies by surficial processes operating under continental conditions. The major uranium deposits of North America illustrate this. The quartz-pebble conglomerate uranium deposits of Elliot Lake, Ontario, have thorium-rich uranium minerals that indicate a detrital origin. With the development of an oxygenic atmosphere before 1,700 m.y. ago, uranium was transported in solution in meteoric surface and near-surface ground water, and produced pitchblende veins in fractures in the basement and in lava flows in terrestrial environments. This accounts for the closee association of fluvial sediments with the pitchblende deposits at Beaverlodge, Rabbit Lake, Baker Lake, and Great Bear Lake, Canada. The development of land plants about 300 m.y. ago produced favorable environments within the terrestrial sandstones themselves, and resulted in the tabular uranium orebodies of the Colorado Plateau. The close relation of tabular orebodies to sedimentation is apparent when compared to recent fluvial sedimentation. In Wyoming, the stratigraphic restriction of the boundary-roll deposits to a few zones in Eocene rocks results from their being remobilized tabular deposits

  8. Environmental restoration of uranium mines in Canada: Progress over 52 years

    International Nuclear Information System (INIS)

    Feasby, D.G.

    1997-01-01

    In Canada, the technology for disposal of uranium mine wastes and reclamation of mines has evolved over a period of 52 years. Early practice involved dumping untreated wastes into the nearest depression or lake and leaving rock and infrastructure in place. Now, the practice is to deposit chemically-stabilized tailings, waste rock and building rubble into highly engineered waste management facilities or mine openings. Similarly the ''footprint'' of the mining activity has been reduced to a very small area and the site is restored as-close-as-possible to pre-mining status. This paper describes the evolution of disposal and reclamation methods and the criteria which have determined the development path followed. Remediation techniques to bring older and now unacceptable tailings deposits into satisfactory compliance with current regulations are reviewed. Some monitoring results are presented. All of the uranium mines in Elliot Lake, Ontario, a large uranium producer since 1957, are now permanently closed. Considerable progress has been made on decommissioning the tailings areas by developing long term maintenance of water covers on some, and water treatment plants and stable soil covers on the others. The innovative methods being used to develop the water covers are described, along with the challenges remaining. Methods now under development in Saskatchewan for subaqueous deposition of paste tailings for permanent disposal in mined out open pits are also described. This method will provide for the first time, ''walkaway'', meaning no long term monitoring and maintenance will be required

  9. A meta-analytic review of Elliot's (1999 Hierarchical Model of Approach and Avoidance Motivation in the sport, physical activity, and physical education literature

    Directory of Open Access Journals (Sweden)

    Marc Lochbaum

    2017-03-01

    Conclusion: Future research is encouraged to grow and enrich the understanding of achievement goals within Elliot's complete Hierarchical Model of Approach and Avoidance Motivation to include both antecedents and outcomes simultaneously to improve upon the understanding of achievement motivation in sport, exercise, and physical activity settings.

  10. Seismic and radon monitoring of Algocen site at Elliot Lake

    International Nuclear Information System (INIS)

    1981-03-01

    Remedial works to reduce radon/radon daughters to acceptable levels in houses in Elliot Lake have been going on for the last three years under the Atomic Energy Control Board (AECB) remedial action program. In December 1978, a routine inspection of treated houses showed extensions to cracks already filled, and the opening up of filled cracks. The homeowners attributed this to the blasting operations for building construction which were going on in town at that time. This prompted the need to monitor any subsequent major scale blasting in the town and to record the damages in nearby houses. This report presents the results of monitoring one such major blasting operation which was carried out between March 1979 and June 1979 for the building of the Algocen Shopping Mall east of Hutchison Avenue. The AECB were concerned about the possible damage to the houses along Hutchison Avenue which had already received remedial treatment to prevent the entry of radon gas, and authorized DSMA/Acres to record the level of vibrations and damages in these houses during the blasting period. (author)

  11. Temporal evolution of bacterial communities associated with the in situ wetland-based remediation of a marine shore porphyry copper tailings deposit.

    Science.gov (United States)

    Diaby, N; Dold, B; Rohrbach, E; Holliger, C; Rossi, P

    2015-11-15

    Mine tailings are a serious threat to the environment and public health. Remediation of these residues can be carried out effectively by the activation of specific microbial processes. This article presents detailed information about temporal changes in bacterial community composition during the remediation of a section of porphyry copper tailings deposited on the Bahía de Ite shoreline (Peru). An experimental remediation cell was flooded and transformed into a wetland in order to prevent oxidation processes, immobilizing metals. Initially, the top oxidation zone of the tailings deposit displayed a low pH (3.1) and high concentrations of metals, sulfate, and chloride, in a sandy grain size geological matrix. This habitat was dominated by sulfur- and iron-oxidizing bacteria, such as Leptospirillum spp., Acidithiobacillus spp., and Sulfobacillus spp., in a microbial community which structure resembled acid mine drainage environments. After wetland implementation, the cell was water-saturated, the acidity was consumed and metals dropped to a fraction of their initial respective concentrations. Bacterial communities analyzed by massive sequencing showed time-dependent changes both in composition and cell numbers. The final remediation stage was characterized by the highest bacterial diversity and evenness. Aside from classical sulfate reducers from the phyla δ-Proteobacteria and Firmicutes, community structure comprised taxa derived from very diverse habitats. The community was also characterized by an elevated proportion of rare phyla and unaffiliated sequences. Numerical ecology analysis confirmed that the temporal population evolution was driven by pH, redox, and K. Results of this study demonstrated the usefulness of a detailed follow-up of the remediation process, not only for the elucidation of the communities gradually switching from autotrophic, oxidizing to heterotrophic and reducing living conditions, but also for the long term management of the remediation

  12. Characterization and dewatering of flotation technological tailings

    Directory of Open Access Journals (Sweden)

    Grigorova I.

    2014-01-01

    Full Text Available The treatment of flotation tailings is today a subject of interest in mineral processing because of the potential of wasted materials as an actual mineral resource and because of environmental reasons. Decantation ponds are found at almost every mine in the world. They are large earth fill dams containing the residue of the milling process to extract metals from mined ores. Traditional wet tailings disposal has been problematic due to the risk of ground water contamination and the difficulty in rehabilitating storage sites. Tailings dams are at risk of failure due to leakage, instability, liquefaction, and poor design. In the last few years the use of paste technology in the disposal of mine tailings is increasingly studied as an option to conventional tailings dams. The Lucky Invest Concentrator is located in the Eastern Rhodopes Mountain of Bulgaria. Since 1959 lead-zinc ores are dressed. Finally, during the flotation cycle lead and zinc concentrates are produced. The final technological processing waste precipitates in tailing pond. Research and development program has started to established opportunities to obtain dry deposit of the ore processing residue and analyses the feature of new tailing disposal method. The tailings particle size distributions and chemical compositions were determined. The data from laboratory and pilot scale tests clearly illustrate that there are the possibilities to obtaine lead-zinc dewatered tailings. The experimental results show that new cyclone modifications have a potential in dewatering technology of flotation tailings. It appears that dewatering cyclones can be an approach on new tailings pond elimination technology.

  13. Mature fine tailings from oil sands processing harbour diverse methanogenic communities

    Energy Technology Data Exchange (ETDEWEB)

    Penner, T.J.; Foght, J.M. [Alberta Univ., Edmonton, AB (Canada). Dept. of Biological Sciences

    2010-06-15

    Syncrude's bitumen extraction process produces a fine tailings slurry consisting of water, sand, fines, residual bitumen and naphtha diluent. Following rapid settling of the sand fraction, the tailings are stored in large settling ponds to form a thick mature fine tailings (MFT). This paper discussed the potential benefits of methane production on management of the settling basins. Enhanced methanogenesis accelerates densification and improves the rheological properties of MFT. In this study molecular techniques were used to characterize the methanogenic communities in uncultivated MFT samples to determine the diversity present in the Mildred Lake Settling Basin (MLSB) and West In-Pit tailings deposit. The flux of methane is currently estimated at about 40 million L/day at the MLSB. Clone libraries of amplified archaeal and bacterial 16S rRNA genes were created in order to analyze the methanogenic consortia in MFT samples from depth profiles in the 2 tailings deposits. The archaeal sequences, whose closest matches were primarily cultivated methanogens, were comparable within and between basins and were mostly affiliated with acetoclastic Methanosaeta spp. However, bacterial clone libraries were diverse, with most sequences relating to Proteobacteria, including some presumptive nitrate-, iron-, or sulfate-reducing, hydrocarbon-degrading genera. The study showed that MFT consists of a diverse community of prokaryotes that may be responsible for producing methane from substrates indigenous to the MFT. These findings contribute to a better understanding of the biogenesis of methane and densification of MFT in oil sands tailings deposits. The results from this study will help determine strategies to control and exploit microbial activities in these large systems and improve the understanding of methanogenic environments. 43 refs., 2 tabs., 3 figs.

  14. Overview of the environmental impact assessment for the proposed expansion of the Elliot Lake Ontario uranium mines

    International Nuclear Information System (INIS)

    Gorber, D.M.; Graham, R.G.; Ibbotson, B.G.

    1978-01-01

    As a result of the resurgence in the demand for uranium, Denison Mines Limited and Rio Algom Limited began preparations, in 1973 and 1974 respectively, for expansion of their facilities at Elliot Lake, Ontario. These programmes involved not only the expansion of facilities currently in operation in the area, but also the rehabilitation of non-operating properties that were previously used during the 1960's. This paper reviews the methodology employed during the environmental assessment study of the proposed expansion and highlights the long and short-term strategies recommended

  15. Tailings management best practice: a case study of the McClean Lake JEB Tailings Management Facility

    International Nuclear Information System (INIS)

    Tremblay, M.A.J.; Rowson, J.

    2005-01-01

    COGEMA Resources Inc. (which is part of the Areva Group) is a Canadian company with its head office in Saskatoon, Saskatchewan. It owns and operates mining and milling facilities in Northern Saskatchewan, which produce uranium concentrate. McClean Lake Operation commenced production in 1999 and its tailings management facility represents the state of the art for tailings management in the uranium industry in Canada. Tailings disposal has the potential to cause effects in the surrounding receiving environment primarily through migration of soluble constituents from the facility to surface water receptors. In-pit disposal or mill tailings has become the standard in the uranium mining industry in Northern Saskatchewan. This method or tailings management demonstrates advances in terms of worker radiation protection and containment of soluble constituents both during operations and into the long term. Sub-aqueous deposition of tailings protects personnel from exposure to radiation and airborne emissions and prevents freezing of tailings, which can hinder consolidation. The continuous inflow of groundwater to the facility is achieved during operations, through control of water levels within the facility. This ensures hydrodynamic containment, which prevents migration of soluble radionuclides and heavy metals into the surrounding aquifer during operations. The environmental performance of the decommissioned facility depends upon the rate of release of contaminants to the receiving environment. The rate of constituent loading to the receiving environment will ultimately be governed by the concentrations of soluble constituents within the tailings mass, the mechanisms for release from the tailings to the surrounding groundwater system, and transport of constituents within the groundwater pathway to the receiving environment. The tailings preparation process was designed to convert arsenic into a stable form to reduce soluble concentrations within the tailings mass. The

  16. Geochemical and mineralogical controls on mine tailings rehabilitation and vegetation, Otago Schist, New Zealand

    International Nuclear Information System (INIS)

    Craw, D.; Rufaut, C.

    2017-01-01

    Large areas (square kilometre scale) of mine tailings have been deposited from placer gold mines in Central Otago, and are being deposited at Macraes orogenic gold mine in east Otago. Establishment of vegetation on these tailings involves at least some provision of plant nutrients from the rock. Phosphorus is the principal limiting nutrient, as the c. 1000 mg/kg P in accessory apatite, most abundant in micaceous schist, is only sparingly bioavailable on timescales of weeks to months. Nitrogen is an important limiting nutrient but schist, especially micaceous schist, typically contains 500-1000 mg/kg N, and this nitrogen is readily leachable with water on timescales of weeks to months. Arsenic uptake from tailings by pasture species is significant (< 90 mg/kg dry weight), but elevated As in tailings substrates (c. 1500 mg/kg) does not adversely affect plant health. Capping of tailings with variably oxidised schist is the most effective way of facilitating revegetation, and some addition of phosphatic fertiliser is desirable but other nutrients, including nitrogen, are adequately bioavailable in a schist cap and underlying tailings. (author).

  17. Paste pumping and deposition field trials and concepts on Syncrude's dewatered mature fine tailings MFT centrifuge cake

    Energy Technology Data Exchange (ETDEWEB)

    Lahaie, R. [Syncrude Canada Ltd., Edmonton, AB (Canada); Ahmed, I.; Labelle, M.; Brown, R. [Golder Paste Technology, Sudbury, ON (Canada)

    2009-07-01

    This presentation discussed a paste pumping and deposition field study conducted on dewatered mature fine tailings (MFT) located at Syncrude's Mildred Lake operation. Bench scale rheological examinations of centrifuge cakes and design field testing are used to determine the pumpability of MFT centrifuge cakes. The study included a transportation assessment for the conveyor and positive displacement pumps and pipelines, as well as geotechnical and environmental analyses of bulk materials. Flocculant optimization and centrifuge operational parameter assessments were conducted. Pressure differential and flow rate data were captured in the field studies in order to determine pipeline friction loss. The study showed that pipe friction factors can be obtained using the Bingham plastic model. A natural deposition angle was determined for the MFT centrifuged cake. The study showed that the cake must be sheared in order to reduce yield stress before pumping. It was concluded that displacement pumps can be used to reduced pipeline friction factors. tabs., figs.

  18. Geochemistry of Mine Waste and Mill Tailings, Meadow Deposits, Streambed Sediment, and General Hydrology and Water Quality for the Frohner Meadows Area, Upper Lump Gulch, Jefferson County, Montana

    Science.gov (United States)

    Klein, Terry L.; Cannon, Michael R.; Fey, David L.

    2004-01-01

    Frohner Meadows, an area of low-topographic gradient subalpine ponds and wetlands in glaciated terrane near the headwaters of Lump Gulch (a tributary of Prickly Pear Creek), is located about 15 miles west of the town of Clancy, Montana, in the Helena National Forest. Mining and ore treatment of lead-zinc-silver veins in granitic rocks of the Boulder batholith over the last 120 years from two sites (Frohner mine and the Nellie Grant mine) has resulted in accumulations of mine waste and mill tailings that have been distributed downslope and downstream by anthropogenic and natural processes. This report presents the results of an investigation of the geochemistry of the wetlands, streams, and unconsolidated-sediment deposits and the hydrology, hydrogeology, and water quality of the area affected by these sources of ore-related metals. Ground water sampled from most shallow wells in the meadow system contained high concentrations of arsenic, exceeding the Montana numeric water-quality standard for human health. Transport of cadmium and zinc in ground water is indicated at one site near Nellie Grant Creek based on water-quality data from one well near the creek. Mill tailings deposited in upper Frohner Meadow contribute large arsenic loads to Frohner Meadows Creek; Nellie Grant Creek contributes large arsenic, cadmium, and zinc loads to upper Frohner Meadows. Concentrations of total-recoverable cadmium, copper, lead, and zinc in most surface-water sites downstream from the Nellie Grant mine area exceeded Montana aquatic-life standards. Nearly all samples of surface water and ground water had neutral to slightly alkaline pH values. Concentrations of arsenic, cadmium, lead, and zinc in streambed sediment in the entire meadow below the mine waste and mill tailings accumulations are highly enriched relative to regional watershed-background concentrations and exceed consensus-based, probable-effects concentrations for streambed sediment at most sites. Cadmium, copper, and

  19. Modeling the emission, transport and deposition of contaminated dust from a mine tailing site.

    Science.gov (United States)

    Stovern, Michael; Betterton, Eric A; Sáez, A Eduardo; Villar, Omar Ignacio Felix; Rine, Kyle P; Russell, Mackenzie R; King, Matt

    2014-01-01

    Mining operations are potential sources of airborne particulate metal and metalloid contaminants through both direct smelter emissions and wind erosion of mine tailings. The warmer, drier conditions predicted for the Southwestern US by climate models may make contaminated atmospheric dust and aerosols increasingly important, due to potential deleterious effects on human health and ecology. Dust emissions and dispersion of contaminants from the Iron King Mine tailings in Dewey-Humboldt, Arizona, a Superfund site, are currently being investigated through in situ field measurements and computational fluid dynamics modeling. These tailings are significantly contaminated with lead and arsenic with an average soil concentration of 1616 and 1420 ppm, respectively. Similar levels of these contaminants have also been measured in soil samples taken from the area surrounding the mine tailings. Using a computational fluid dynamics model, we have been able to model dust transport from the mine tailings to the surrounding region. The model includes a distributed Eulerian model to simulate fine aerosol transport and a Lagrangian approach to model fate and transport of larger particles. In order to improve the accuracy of the dust transport simulations both regional topographical features and local weather patterns have been incorporated into the model simulations.

  20. The effect of flocculant on the geotechnical properties of mature fine tailings : An experimental study

    NARCIS (Netherlands)

    Yao, Y.; Van Tol, A.F.; Van Paassen, L.A.

    2012-01-01

    When oil sands tailings are deposited in a tailing pond, they settle and segregate to create a layer of stagnant water on top that is reused in oil extraction and a dense mixture of clay, silt and water on the bottom which is referred to as mature fine tailings (MFT). Dewatering of MFT is a problem

  1. Numerical modeling of drying and consolidation of fine sediments and tailings

    NARCIS (Netherlands)

    Van der Meulen, J.; Van Tol, A.F.; Van Paassen, L.A.; Heimovaara, T.J.

    2012-01-01

    The extraction and processing of many mineral ores result in the generation of large volumes of fine-grained residue or tailings. These fine sediments are deposited as a slurry with very high water contents and lose water after deposition due to self-weight consolidation. When the surface is exposed

  2. Maggie's Struggle in Placing Her Existence at the Patriarchal Society in the Mill on the Floss by George Elliot

    OpenAIRE

    INDRIANI, FRISCA ARUM

    2013-01-01

    Novel The Mill on the Floss is one of George Elliot's novels that describing the situation and condition of the English society and also representing human life in 1837-1901 century which is called Victorian Era. At the moment, women were dominated by men and considered inferior. The condition is portrayed in this novel because the novel tells about the life of women, especially the life of the main female character, Maggie Tulliver, who is the victim of the standard beauty in her family. It ...

  3. Oil sands tailings technology : understanding the impact to reclamation

    Energy Technology Data Exchange (ETDEWEB)

    Mamer, M. [Suncor Energy Inc., Fort McMurray, AB (Canada)

    2010-07-01

    This paper discussed tailings management techniques at oil sands mines and their effects on reclamation schedules and outcomes. The layer of mature fine tailings (MFT) that forms in tailings ponds does not settle within a reasonable time frame, requiring more and larger tailings ponds for storing MFT. Consolidated tailings (CT) technology was developed to accelerate the consolidation of MFT, although the process nonetheless takes decades. CT is produced from mixing tailings sand, gypsum, and MFT to create a mixture that will consolidate more quickly and release water. However, CT production is tied to the extraction process, making it applicable only when the plant is operational, and a precise recipe and accurate injection are required for CT to work. In tailings reduction operations (TRO), a new approach to tailings management, MFT is mixed with a polymer flocculant, deposited in thin layers, and allowed to dry. TRO has a significant advantage over CT in that the latter takes up to 30 years to consolidate to a trafficable surface compared to weeks for TRO. TRO allows MFT to be consumed more quickly than it is produced, reducing need to build more tailings ponds, operates independent of plant operations, accelerates the reclamation time frame, and offers enhanced flexibility in final tailings placement sites. TRO also creates a dry landscape, to which well established reclamation techniques can be applied. Dried MFT is a new material type, and research is exploring optimum reclamation techniques. 2 figs.

  4. Submarine Tailings Disposal (STD—A Review

    Directory of Open Access Journals (Sweden)

    Bernhard Dold

    2014-07-01

    Full Text Available The mining industry is a fundamental industry involved in the development of modern society, but is also the world’s largest waste producer. This role will be enhanced in the future, because ore grades are generally decreasing, thus leading to increases in the waste/metal production ratio. Mine wastes deposited on-land in so-called tailings dams, impoundments or waste-dumps have several associated environmental issues that need to be addressed (e.g., acid mine drainage formation due to sulphide oxidation, geotechnical stability, among others, and social concerns due to land use during mining. The mining industry recognizes these concerns and is searching for waste management alternatives for the future. One option used in the past was the marine shore or shallow submarine deposition of this waste material in some parts of the world. After the occurrence of some severe environmental pollution, today the deposition in the deep sea (under constant reducing conditions is seen as a new, more secure option, due to the general thought that sulphide minerals are geochemically stable under the reduced conditions prevailing in the deep marine environment. This review highlights the mineralogical and geochemical issues (e.g., solubility of sulphides in seawater; reductive dissolution of oxide minerals under reducing conditions, which have to be considered when evaluating whether submarine tailings disposal is a suitable alternative for mine waste.

  5. The radon concentration profile and the flux from a pilot-scale layered tailings pile

    International Nuclear Information System (INIS)

    Zettwoog, P.; Fourcade, N.; Campbell, F.E.; Caplan, H.

    1982-01-01

    A pilot tailings model was constructed to demonstrate the feasibility of the sub-aerial technique of tailing deposition for the proposed uranium mine and mill at Key Lake, Saskatchewan. A series of radon measurements were made on the model and results obtained for the radon concentration profile in the tailings, and for the flux from the surface. The results were compared with the model calculations of Zettwoog. (U.K.)

  6. Indoor-outdoor concentrations of fine particulate matter in school building microenvironments near a mine tailing deposit

    Directory of Open Access Journals (Sweden)

    Leonardo Martínez

    2016-11-01

    Full Text Available Indoor air quality in school classrooms is a major pediatric health concern because children are highly susceptible to adverse effects from xenobiotic exposure. Fine particulate matter (PM2.5 emitted from mining waste deposits within and near cities in northern Chile is a serious environmental problem. We measured PM2.5 in school microenvironments in urban areas of Chañaral, a coastal community whose bay is contaminated with mine tailings. PM2.5 levels were measured in six indoor and outdoor school environments during the summer and winter of 2012 and 2013. Measurements were taken during school hours on two consecutive days. Indoor PM2.5 concentrations were 12.53–72.38 μg/m3 in the summer and 21.85–100.53 μg/m3 in winter, while outdoor concentrations were 11.86–181.73 μg/m3 in the summer and 21.50–93.07 μg/m3 in winter. Indoor/outdoor ratios were 0.17–2.76 in the summer and 0.64–4.49 in winter. PM2.5 levels were higher in indoor microenvironments during the winter, at times exceeding national and international recommendations. Our results demonstrate that indoor air quality Chañaral school microenvironments is closely associated with outdoor air pollution attributable to the nearby mine tailings. Policymakers should enact environmental management strategies to minimize further environmental damage and mitigate the risks that this pollution poses for pediatric health.

  7. A review of methods developed to solve the issue of weak mature fine tailings

    Energy Technology Data Exchange (ETDEWEB)

    Long, M.; Ulrich, A.; Sego, D. [Alberta Univ., Edmonton, AB (Canada). Dept. of Civil and Environmental Engineering

    2010-07-01

    This PowerPoint presentation discussed new techniques for managing weak mature fine tailings (MFT) produced during the oil sands refining process. The techniques included non-segregating tailings, freeze-thaw dewatering, atmospheric drying, and dewatering by vegetation. MFT are produced after water from oil sands slurries is decanted. MFT contain a complex chemical interaction of clays and hydrocarbons. A large proportion of the solids in MFTs are clay minerals and clay-sized. MFTs have low rates of sedimentation and consolidation, and a low bearing capacity and shear strength with high compressibility. MFTs cannot physically support remediation activities, and must be stored in an impounded area. More aggressive dewatering and stabilization processes are required for MFTs. Atmospheric drying involves the deposition of tailings in order to evaporate water. Thin- and thick-lift deposition schemes are used. Atmospheric drying is often complicated by the formation of a bitumen skin over the tailings. Various case studies were presented. Space requirements and issues related to clay content were reviewed. tabs., figs.

  8. Room temperature photoluminescence spectrum modeling of hydrogenated amorphous silicon carbide thin films by a joint density of tail states approach and its application to plasma deposited hydrogenated amorphous silicon carbide thin films

    International Nuclear Information System (INIS)

    Sel, Kıvanç; Güneş, İbrahim

    2012-01-01

    Room temperature photoluminescence (PL) spectrum of hydrogenated amorphous silicon carbide (a-SiC x :H) thin films was modeled by a joint density of tail states approach. In the frame of these analyses, the density of tail states was defined in terms of empirical Gaussian functions for conduction and valance bands. The PL spectrum was represented in terms of an integral of joint density of states functions and Fermi distribution function. The analyses were performed for various values of energy band gap, Fermi energy and disorder parameter, which is a parameter that represents the width of the energy band tails. Finally, the model was applied to the measured room temperature PL spectra of a-SiC x :H thin films deposited by plasma enhanced chemical vapor deposition system, with various carbon contents, which were determined by X-ray photoelectron spectroscopy measurements. The energy band gap and disorder parameters of the conduction and valance band tails were determined and compared with the optical energies and Urbach energies, obtained by UV–Visible transmittance measurements. As a result of the analyses, it was observed that the proposed model sufficiently represents the room temperature PL spectra of a-SiC x :H thin films. - Highlights: ► Photoluminescence spectra (PL) of the films were modeled. ► In the model, joint density of tail states and Fermi distribution function are used. ► Various values of energy band gap, Fermi energy and disorder parameter are applied. ► The model was applied to the measured PL of the films. ► The proposed model represented the room temperature PL spectrum of the films.

  9. Environmental impact of uranium mining and milling

    International Nuclear Information System (INIS)

    Dory, A.B.

    1981-08-01

    The Atomic Energy Control Board is now involved from the early planning stages in the development of uranium mine/mill facilities. As a result, new facilities (including tailings management areas) are designed and developed to meet a high standard. The impact of the mines and tailings areas in the Elliot Lake area on ground and surface waters and air quality is discussed in detail

  10. Field performance of de-watered fluid fine tailings for oil sands reclamation

    Energy Technology Data Exchange (ETDEWEB)

    Ward Wilson, G.; Kabwe, Louis [University of Alberta (Canada); Donahue, Robert [Applied Geochemical Engineering Inc. (Canada); Lahaie, Rick [Syncrude Canada Ltd (Canada)

    2011-07-01

    This document presents research carried out by Syncrude Canada Ltd and its partners to evaluate several methods of de-watering fluid fine tailings to increase the solids content and at the same time produce a tailings profile which will permit final reclamation. Several de-watering methods are discussed in this paper, particularly in-line flocculation and centrifuged fluid fine tailings. First, in-line flocculation with organic polymers is discussed followed by thin left deposition, then the flocculation and centrifugation process to produce a paste- like material that is deposited in a thicker layer is presented. This document details the preliminary performance of both discussed methods; extensive instrumentation was used to measure de-watering rates due to consolidation, atmospheric drying, downward drainage to the foundation materials, and freeze/thaw consolidation. Finally, a summary of the measured results of de-watering rates and numerical model results obtained from the SoilCover model are presented and discussed.

  11. Jarosite formation in the uranium processing circuit of Denison Mines Limited, Elliot Lake, Ontario

    International Nuclear Information System (INIS)

    Dutrizac, J.E.

    1985-04-01

    Jarosite precipitation occurs in several parts of the uranium processing circuit of Denison Mines Limited, Elliot Lake, Ontario. Extensive precipitation of jarosite takes place in the filter cloth and on the drum face of the secondary drum filters, and this precipitation causes severe operating difficulties. Precipitation of jarosite is also observed in the ion exchange beads, but it is not known whether the jarosite is responsible for the observed decrease in resin efficiency. The resin beads are also rimmed with significant quantities of silica, lead, phosphate, sulphate, etc. which could be responsible for the fouling of the resin. In every instance, potassium jarosite, containing only minor amounts of sodium or ammonium, was the observed species; the potassium likely originates from the acid leaching of muscovite in the ore. Potential methods of avoiding the jarosite problem are discussed, but these may not be compatible with the overall process requirements

  12. Report on investigation of remedial measures for the radiation reduction and radioactive decontamination of Elliot Lake, Ontario

    International Nuclear Information System (INIS)

    1981-02-01

    This is the fourth annual report on a program to monitor and reduce radon daughter exposures in the town of Elliot Lake, Ontario. Twelve month's WL survey measurements were completed in 1980 and showed that 22 houses exceeded the remedial action criterion of 0.02 WL. In a few cases gamma radiation levels were high enough to require remedial action in driveways and public areas, but not inside houses. During 1980 remedial work was carried out on 85 buildings; work was completed on 58. The most frequent routes of entry for radon and radon daughters were untrapped weeping tile connected to a floor drain or sump, and the wall to floor joint

  13. Tailings dewatering in the oil sands

    Energy Technology Data Exchange (ETDEWEB)

    Longo, S.; Labelle, M. [Golder Paste Technology, Sudbury, ON (Canada); Wislesky, I. [Golder Associates Ltd., Calgary, AB (Canada)

    2010-07-01

    Alberta's Directive 074 was established to reduce fluid tailings produced during oil sands extraction processes. This PowerPoint presentation examined some of the dewatering strategies available for oil sands operators and provided recommendations for implementing a dewatering plan. Sites must be evaluated in order to determine their chemistry, mineralogy, and the total quantity of material to be handled. The availability of potential additives must also be considered. Process technologies must be selected in relation to the operator's depositional strategy. Each site will require its own unique dewatering and depositional strategy. Dewatering technologies include thickening; in-line flocculation; centrifuge; co-mingling; and various new technologies such as electro-osmosis. Laboratory testing programs include index tests, primary stream thickening, and mini-pilot plant testing. The performance of various testing formats was evaluated. Thickening and depositional techniques were reviewed. tabs., figs.

  14. Use of the emergency room in Elliot Lake, a rural community of Northern Ontario, Canada.

    Science.gov (United States)

    Harris, L; Bombin, M; Chi, F; DeBortoli, T; Long, J

    2004-01-01

    There is ample documentation that use of hospital emergency facilities for reasons other than urgencies/emergencies results in clogged services in many urban centers. However, little has been published about similar misuse of emergency rooms/departments in rural and remote areas, where the situation is usually compounded by a scarcity of healthcare professionals. In Canada there is a shortage of physicians in rural and remote areas as a consequence of misdistribution (most physicians staying in southern urban centers after residence), and there is a chronic misuse of facilities meant for urgencies/emergencies to cope with primary healthcare needs. We address the problem in Elliot Lake, a rural Northern Ontario community of 12,000 people. The economy of Elliot Lake was based on uranium mining until the mid-1990s, when it drastically changed to become a center for affordable retirement and recreational tourism. As a consequence, at the present time the proportion of seniors in Elliot Lake doubles the Canadian average. Our objectives are to elucidate the demographics of emergency room (ER) clients and the effect of the elderly population; the nature of ER use; the perceived level of urgency of clients versus health professionals; and possible alternatives offered to non-urgent/emergency visits. This is the first study of the kind in Northern Ontario, a region the size of France. The study, conducted in July 2001, used a prospective survey, completed by patients and attending clinicians at the time of a patient's presentation to the ER of St Joseph's General Hospital. This hospital is staffed by family physicians, a nurse practitioner, and registered nurses (RNs). The catchment area population (town plus surrounding areas) of the hospital is approximately 18,000 people. ER clients were interviewed verbally, and the attending health professionals responded to written questionnaires. Demographics were recorded (age, sex, employment and marital status), as was each client

  15. Gold tailings as a source of waterborne uranium contamination of ...

    African Journals Online (AJOL)

    driniev

    2004-04-02

    Apr 2, 2004 ... Dissolved uranium (U) from the tailings deposits of various gold mines in South Africa has .... tivity), probes for measuring hydro-chemical (pH, Eh), physical ... Due to the pumping scheme, rain events in the catchment do not.

  16. A descriptive and quantitative approach regarding erosion and development of landforms on abandoned mine tailings: New insights and environmental implications from SE Spain

    Science.gov (United States)

    Martín Duque, J. F.; Zapico, I.; Oyarzun, R.; López García, J. A.; Cubas, P.

    2015-06-01

    The San Cristóbal-Perules mining site in Mazarrón in southeast Spain was subjected to about a hundred years of intense mining activity for lead, silver, and zinc. Metallurgical operations (smelting, calcination, gravity concentration) carried out during the late nineteenth century-early twentieth century induced significant land transformation, and the most conspicuous wastes of this period consist of a chaotic piling of 'old' tailing deposits. Later on, during the mid-twentieth century, 'modern' tailings resulting from froth flotation were accumulated filling small valleys; these latter valley-fill tailings rose sequentially according to the upstream construction method, progressively raising the level of the dam during the process. Once abandoned, both types of tailing deposits underwent severe erosion, resulting in a mosaic of erosional and sedimentary landforms developed upon (e.g., gully formation) and within them (e.g., piping). We made an inventory and classification of these landforms. Our study shows the geomorphic work to reestablish a new steady state between the tailings deposits and the local erosive conditions. This scenario implies several hazards related to the extremely high heavy metal contents of these tailings and the geomorphic instability of the deposits. We also quantified the tailings tonnage and erosion that occurred at one of the tailings dams (El Roble). As shown by an oblique aerial photograph taken in 1968, this dam had a terraced topography, whereas in 2013 this morphology had evolved into a badland-type relief with deep parallel gullies. By recognizing and surveying specific, remnant points along the benches and outslopes of the older terraced topography, we were able to build up a first digital elevation model (DEM1) reflecting the initial topography. A second DEM, this time showing the present topography, allowed quantification of erosion via Material Loss = DEM1 - DEM2. This yields an erosion rate (1968-2009) of 151.8 Mg (MT) ha

  17. Mine tailings dams: Characteristics, failure, environmental impacts, and remediation

    International Nuclear Information System (INIS)

    Kossoff, D.; Dubbin, W.E.; Alfredsson, M.; Edwards, S.J.; Macklin, M.G.; Hudson-Edwards, K.A.

    2014-01-01

    On a global scale demand for the products of the extractive industries is ever increasing. Extraction of the targeted resource results in the concurrent production of a significant volume of waste material, including tailings, which are mixtures of crushed rock and processing fluids from mills, washeries or concentrators that remain after the extraction of economic metals, minerals, mineral fuels or coal. The volume of tailings is normally far in excess of the liberated resource, and the tailings often contain potentially hazardous contaminants. A priority for a reasonable and responsible mining organization must be to proactively isolate the tailings so as to forestall them from entering groundwaters, rivers, lakes and the wind. There is ample evidence that, should such tailings enter these environments they may contaminate food chains and drinking water. Furthermore, the tailings undergo physical and chemical change after they have been deposited. The chemical changes are most often a function of exposure to atmospheric oxidation and tends to make previously, perhaps safely held contaminants mobile and available. If the tailings are stored under water, contact with the atmosphere is substantially reduced, thereby forestalling oxygen-mediated chemical change. It is therefore accepted practice for tailings to be stored in isolated impoundments under water and behind dams. However, these dams frequently fail, releasing enormous quantities of tailings into river catchments. These accidents pose a serious threat to animal and human health and are of concern for extractive industries and the wider community. It is therefore of importance to understand the nature of the material held within these dams, what best safety practice is for these structures and, should the worst happen, what adverse effects such accidents might have on the wider environment and how these might be mitigated. This paper reviews these factors, covering the characteristics, types and magnitudes

  18. Can There Ever Be Enough to Impact Water Quality? Evaluating BMPs in Elliot Ditch, Indiana Using the LTHIA-LID Model

    Science.gov (United States)

    Rahman, M. S.; Hoover, F. A.; Bowling, L. C.

    2017-12-01

    Elliot Ditch is an urban/urbanizing watershed located in the city of Lafayette, IN, USA. The city continues to struggle with stormwater management and combined sewer overflow (CSO) events. Several best-management practices (BMP) such as rain gardens, green roofs, and bioswales have been implemented in the watershed, but the level of adoption needed to achieve meaningful impact is currently unknown. This study's goal is to determine what level of BMP coverage is needed to impact water quality, whether meaningful impact is determined by achieving water quality targets or statistical significance. A power analysis was performed using water quality data for total suspended solids (TSS), E.coli, total phosphorus (TP) and nitrate (NO3-N) from Elliot Ditch from 2011 to 2015. The minimum detectable difference (MDD) was calculated as the percent reduction in load needed to detect a significant change in the watershed. The water quality targets were proposed by stakeholders as part of a watershed management planning process. The water quality targets and the MDD percentages were then compared to simulated load reductions due to BMP implementation using the Long-term Hydrologic Impact Assessment-Low Impact Development (LTHIA-LID) model. Seven baseline model scenarios were simulated by implementing the maximum number of each of six types of BMPs (rain barrels, permeable patios, green roofs, grassed swale/bioswales, bioretention/rain gardens, and porous pavement), as well as all the practices combined in the watershed. These provide the baseline for targeted implementation scenarios designed to determine if statistically and physically meaningful load reductions can be achieved through BMP implementation alone.

  19. Tail posture predicts tail damage among weaned piglets

    NARCIS (Netherlands)

    Zonderland, J.J.; Riel, van J.W.; Bracke, M.B.M.; Kemp, B.; Hartog, den L.A.; Spoolder, H.A.M.

    2009-01-01

    Tail biting in pigs is a widespread behavioural vice with significant animal welfare and economic consequences. All too often, tail biting is not diagnosed nor dealt with until tail damage is present. To effectively reduce the negative effects of tail biting, it must be diagnosed in an early stage.

  20. Long-term passive restoration following fluvial deposition of sulphidic copper tailings: nature filters out the solutions.

    Science.gov (United States)

    Nikolic, Nina; Böcker, Reinhard; Nikolic, Miroslav

    2016-07-01

    Despite the growing popularity of ecological restoration approach, data on primary succession on toxic post-mining substrates, under site environmental conditions which considerably differ from the surrounding environment, are still scarce. Here, we studied the spontaneous vegetation development on an unusual locality created by long-term and large-scale fluvial deposition of sulphidic tailings from a copper mine in a pronouncedly xerothermic, calcareous surrounding. We performed multivariate analyses of soil samples (20 physical and chemical parameters) and vegetation samples (floristic and structural parameters in three types of occurring forests), collected along the pollution gradients throughout the affected floodplain. The nature can cope with two types of imposed constraints: (a) excessive Cu concentrations and (b) very low pH, combined with nutrient deficiency. The former will still allow convergence to the original vegetation, while the latter will result in novel, depauperate assemblages of species typical for cooler and moister climate. Our results for the first time demonstrate that with the increasing severity of environmental filtering, the relative importance of the surrounding vegetation for primary succession strongly decreases.

  1. Mercury contamination in soil, tailing and plants on agricultural fields near closed gold mine in Buru Island, Maluku

    Directory of Open Access Journals (Sweden)

    Reginawanti Hindersah

    2018-01-01

    Full Text Available Agricultural productivity in Buru Island, Maluku is threatened by tailings which are generated from formerly gold mine in Botak Mountain in Wamsait Village. Gold that extracted by using mercury was carried out in mining area as well agricultural field.  High content of mercury in tailings and agricultural field pose a serious problem of food production and quality; and further endangers human health. The purpose of this research was to determine the contaminant level of mercury in tailing, soil and its accumulation in edible part of some food crops. Soil, tailing and plant samples for Hg testing were taken by purposive method based on mining activities in Waelata, Waeapo and Namlea sub district. Six soil samples had been analyzed for their chemical properties. Total mercury levels in tailings and plants were measured by Atomic Adsorption Spectrophotometer. This study showed that agricultural field where tailings were deposited contained Hg above the threshold but agricultural area which is far from hot spot did not. Most edible parts of food crops accumulated mercury more than Indonesian threshold for mercury content in food. This evidence explained that tailings deposited on the surface of agricultural field had an impact on soil quality and crop quality. Tailing accumulated on soil will decreased soil quality since naturally soil fertility in agricultural field in Buru is low.

  2. Pre- and post-remediation characterization of acid-generating fluvial tailings material

    Science.gov (United States)

    Smith, Kathleen S.; Walton-Day, Katherine; Hoal, Karin O.; Driscoll, Rhonda L.; Pietersen, K.

    2012-01-01

    The upper Arkansas River south of Leadville, Colorado, USA, contains deposits of fluvial tailings from historical mining operations in the Leadville area. These deposits are potential non-point sources of acid and metal contamination to surface- and groundwater systems. We are investigating a site that recently underwent in situ remediation treatment with lime, fertilizer, and compost. Pre- and post-remediation fluvial tailings material was collected from a variety of depths to examine changes in mineralogy, acid generation, and extractable nutrients. Results indicate sufficient nutrient availability in the post-remediation near-surface material, but pyrite and acid generation persist below the depth of lime and fertilizer addition. Mineralogical characterization performed using semi-quantitative X-ray diffraction and quantitative SEM-based micro-mineralogy (Mineral Liberation Analysis, MLA) reveal formation of gypsum, jarosite, and complex coatings surrounding mineral grains in post-remediation samples.

  3. KEBERADAAN FUNGI MIKORIZA ARBUSKULA DI KAWASAN TAILING TAMBANG EMAS TIMIKA SEBAGAI UPAYA REHABILITASI LAHAN RAMAH LINGKUNGAN (The Presence of Arbuscular Mycorrhizal Fungi in the Tailings of Mining Gold Timika as An Attempt of Environmentally Friendly

    Directory of Open Access Journals (Sweden)

    Suharno Suharno

    2015-01-01

    Full Text Available ABSTRAK Fungi mikoriza arbuskula (FMA berperan penting dalam menunjang rehabilitasi lahan terdegradasi, termasuk lahan tailing. Tujuan penelitian ini adalah untuk mengetahui keberadaan FMA lokal di lahan tailing tambang emas Timika – Papua, Indonesia. Metode yang digunakan adalah survei dengan mengisolasi FMA dari rhizosfer beberapa jenis tumbuhan dominan di kawasan daerah pengendapan pasir sisa tambang. Pengecatan akar untuk melihat infeksi oleh FMA dilakukan dengan trypane blue, sedangkan perhitungan persen infeksinya dilakukan dengan metode slide. Keberadaan spora FMA dilakukan dengan metode wet sieving. Hasil penelitian menunjukkan bahwa terdapat FMA di lahan tailing di kawasan pengendapan Modified Ajkwa Deposition Area (ModADA. Persentase infeksi tertinggi (>50% diketahui pada jenis tumbuhan Ficus adenosperma (86,7%, Brachiaria sp (73,3%, Amomum sp (66,7%, Bidens pilosa (63,3%, dan Musaenda frondosa (56,7%, sedangkan beberapa jenis lain mempunyai persen infeksi yang lebih rendah. Jumlah spora pada rhizosfer tumbuhan Brachiaria sp., F. adenosperma, dan Amomum sp., merupakan yang tertinggi dibanding dengan tumbuhan lain yakni 17, 13, dan 11 spora per 10 g tanah.  ABSTRACT Arbuscular Mycorrhizal Fungi (AMF has an important role in supporting the rehabilitation of degraded land such as tailings. The purpose of this research was to reveal the existence of indigenous AMF in tailing area of gold mine in Timika – Papua, Indonesia. The method was a survey by isolating some types of AMF from rhizosphere of dominant plant in the deposit area of mine sand residue. To define the AMF infected roots was conducted painting roots using trypane blue, where as the calculation of percent infection was carried out using slide methods. The presence of spores of AMF was done by wet sieving method. The results showed that AMF was found in tailings deposition on the Modified Ajkwa Deposition Area (ModADA. The highest percentage infections (>50% was found under

  4. Aqueous-chlorine leaching of typical Canadian uranium ores

    International Nuclear Information System (INIS)

    Haque, K.E.

    1982-01-01

    Laboratory-scale aqueous-chlorine leaches were conducted on quartz-pebble conglomerates, pegmatite and vein-type ores. Optimum leach temperatures, pulp density and retention times were determined. Uranium extraction of 98 per cent was obtained from the Elliot Lake, Madawaska Mines of Bancroft and Rabbit Lake ores, 96 per cent from the Key Lake ore and 86 per cent from the Agnew Lake ore. However, tailings containing 15-20 pCi g -1 of radium-226 were obtained only from the Elliot Lake and Agnew lake quartz-pebble conglomerates and Bancroft pegmatite-type ores by second-stage leaches with HCl. The second-stage leach results indicate that multistage (3 or 4) acid-chloride or salt-chloride leaches might be effective to obtain tailings containing 15-20 pCi 226 Ra g -1 from the high-grade vein-type ores. Comparative reagent-cost estimates show that the sulphuric-acid leach process is far less expensive than aqueous chlorine leaching. Nevertheless, only the aqueous chlorine and acid-chloride leaches in stages are effective in producing tailings containing 15-20 pCi 226 Ra g -1 from the typical Canadian uranium ores. (Auth.)

  5. Flow behaviour and robustness of non-segregating tailings made from filtered/centrifuged MFT

    Energy Technology Data Exchange (ETDEWEB)

    Nik, R.M.; Sego, D.C.; Morgenstern, N.R. [Alberta Univ., Edmonton, AB (Canada). Geotechnical Center

    2010-07-01

    This PowerPoint presentation described an experimental study of a centrifugal dewatering filtration process for mature fine tailings (MFT). Various MFT samples from different oil sands operations were pumped into a filtering centrifuge that produced cake, thin tailings, and filtrate. The MFT was then transformed into non-segregated tailings (NST) and composite tailings (CT). The depositional characteristics of the CT-NST samples were evaluated in a series of flume tests. Flow profiles were presented for various samples. Vane shear tests were also conducted. The yield stress of each sample was compared with its flow duration and solids content. The results of the experimental tests demonstrated that the centrifugal filtration process can be considered as the initial stage of a multi-stage tailings management plan. The filtering centrifuge method can be used to produce robust CTs with higher solids content. Use of the method can decrease the amount of coagulants or flocculants required for further treatment. tabs., figs.

  6. Telling tails: selective pressures acting on investment in lizard tails.

    Science.gov (United States)

    Fleming, Patricia A; Valentine, Leonie E; Bateman, Philip W

    2013-01-01

    Caudal autotomy is a common defense mechanism in lizards, where the animal may lose part or all of its tail to escape entrapment. Lizards show an immense variety in the degree of investment in a tail (i.e., length) across species, with tails of some species up to three or four times body length (snout-vent length [SVL]). Additionally, body size and form also vary dramatically, including variation in leg development and robustness and length of the body and tail. Autotomy is therefore likely to have fundamentally different effects on the overall body form and function in different species, which may be reflected directly in the incidence of lost/regenerating tails within populations or, over a longer period, in terms of relative tail length for different species. We recorded data (literature, museum specimens, field data) for relative tail length (n=350 species) and the incidence of lost/regenerating tails (n=246 species). We compared these (taking phylogeny into account) with intrinsic factors that have been proposed to influence selective pressures acting on caudal autotomy, including body form (robustness, body length, leg development, and tail specialization) and ecology (foraging behavior, physical and temporal niches), in an attempt to identify patterns that might reflect adaptive responses to these different factors. More gracile species have relatively longer tails (all 350 spp., P lost/regenerating tails for nocturnal lizards (all 246 spp., P pressure.

  7. Gold tailings as a source of waterborne uranium contamination of ...

    African Journals Online (AJOL)

    Dissolved uranium (U) from the tailings deposits of various gold mines in South Africa has been found to migrate via seepage and groundwater into adjacent streams. The extent of the associated non-point pollution depends on the concentration of U in the groundwater as well as the volume and rate of groundwater ...

  8. WATER TEMPERATURE and other data from LEWIS B. PULLER, ELLIOT and USS DE WERT in the TOGA Area - Pacific, Caribbean Sea and NW Atlantic from 1986-11-07 to 1987-05-31 (NCEI Accession 9400029)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data in this accession were collected in Caribbean Sea, NW Atlantic (limit-40 W), and TOGA Area - Pacific (30 N to 30 S) from ship ELLIOT, USS DE WERT, and LEWIS...

  9. Chemical and ecotoxicity evaluation of tailings rehabilitated using Technosol

    Science.gov (United States)

    Arán, Diego; Santos, Erika S.; Abreu, Maria Manuela; Macías, Felipe

    2017-04-01

    The Fé mining area was the most important uranium deposit in Spain. In this deposit, the uranium mineralization contains sulfides. Consequently, tailings are a source of polymetallic contamination requiring their rehabilitation in order to decrease the dispersion of potentially hazardous elements (PHEs). The main objective of this work is to evaluate the efficiency of a Technosol application on the rehabilitation of these tailings at chemical and ecotoxicological level. In the field, a layer of 20 cm Technosol with andic and eutrophic characteristic was applied over the tailing (total area: 625 m2). After 20 months, composite samples of Technosol (TEC), recovered tailing (bottom of the Technosol, RT) and tailings without recuperation (T) were collected. These samples were characterized for pH, electric conductivity (EC), PHEs concentration in total fraction and available fraction extracted with rhizosphere-based method. Ecotoxicity bioassays were carried out with two species, Lollium perenne and Trifolium pratense following OECD Guidelines. Three bioassays were carried out: filter paper test and hydroponic test with leachates, and soil test. In leachates (extracted with DIN method) were determined pH, EC and same PHEs than in Technosol/Tailings. Visual aspects, germination, root and shoot elongation and dry biomass were evaluated. The substrate effect on growth of both species was evaluated in pot experiment (500 g Technosol/Tailings per pot, 70% of water-holding capacity) under greenhouse conditions after 69 days by dry shoot biomass. Materials from T had pH 4, EC: 1.2 mS/cm and high total concentrations of several PHEs (g/kg; Al: 46.2; As, Co and Pb: 0.02-0.03; Cu: 0.04; Fe: 63.2 Mn: 1.3; Ni and Zn: 0.1-0.2). However, PHEs concentrations in leachates and available fraction corresponded to 75% of reduction). For both species, the germination percentage and dry biomass weight in filter paper test (Lollium: 62-70%, 38-41 mg; Trifolium: 73-80%, 24-31 mg) and soil

  10. Simulation of windblown dust transport from a mine tailings impoundment using a computational fluid dynamics model

    Science.gov (United States)

    Stovern, Michael; Felix, Omar; Csavina, Janae; Rine, Kyle P.; Russell, MacKenzie R.; Jones, Robert M.; King, Matt; Betterton, Eric A.; Sáez, A. Eduardo

    2014-01-01

    Mining operations are potential sources of airborne particulate metal and metalloid contaminants through both direct smelter emissions and wind erosion of mine tailings. The warmer, drier conditions predicted for the Southwestern US by climate models may make contaminated atmospheric dust and aerosols increasingly important, due to potential deleterious effects on human health and ecology. Dust emissions and dispersion of dust and aerosol from the Iron King Mine tailings in Dewey-Humboldt, Arizona, a Superfund site, are currently being investigated through in situ field measurements and computational fluid dynamics modeling. These tailings are heavily contaminated with lead and arsenic. Using a computational fluid dynamics model, we model dust transport from the mine tailings to the surrounding region. The model includes gaseous plume dispersion to simulate the transport of the fine aerosols, while individual particle transport is used to track the trajectories of larger particles and to monitor their deposition locations. In order to improve the accuracy of the dust transport simulations, both regional topographical features and local weather patterns have been incorporated into the model simulations. Results show that local topography and wind velocity profiles are the major factors that control deposition. PMID:25621085

  11. Simulation of windblown dust transport from a mine tailings impoundment using a computational fluid dynamics model.

    Science.gov (United States)

    Stovern, Michael; Felix, Omar; Csavina, Janae; Rine, Kyle P; Russell, MacKenzie R; Jones, Robert M; King, Matt; Betterton, Eric A; Sáez, A Eduardo

    2014-09-01

    Mining operations are potential sources of airborne particulate metal and metalloid contaminants through both direct smelter emissions and wind erosion of mine tailings. The warmer, drier conditions predicted for the Southwestern US by climate models may make contaminated atmospheric dust and aerosols increasingly important, due to potential deleterious effects on human health and ecology. Dust emissions and dispersion of dust and aerosol from the Iron King Mine tailings in Dewey-Humboldt, Arizona, a Superfund site, are currently being investigated through in situ field measurements and computational fluid dynamics modeling. These tailings are heavily contaminated with lead and arsenic. Using a computational fluid dynamics model, we model dust transport from the mine tailings to the surrounding region. The model includes gaseous plume dispersion to simulate the transport of the fine aerosols, while individual particle transport is used to track the trajectories of larger particles and to monitor their deposition locations. In order to improve the accuracy of the dust transport simulations, both regional topographical features and local weather patterns have been incorporated into the model simulations. Results show that local topography and wind velocity profiles are the major factors that control deposition.

  12. Consolidation of tailings

    International Nuclear Information System (INIS)

    Nelson, J.D.; Wardwell, R.E.; Abt, S.R.; Staub, W.P.

    1983-09-01

    The integrity of cover systems placed on tailings impoundments will be affected by the potential for differential settlement of the tailings surface. Settlement of the sand fraction will occur relatively rapidly. The slimes will take longer time for consolidation and will produce greater settlement. This report reviews the phenomenon of consolidation for saturated and unsaturated tailings. The effect of load application by cover placement and the extent to which dewatering of tailings will cause consolidation are considered. In addition, the feasibility of inducing consolidation by alternative means and the potential applicability of these methods to tailings impoundments reclamation are discussed. Differential settlement of the tailings will cause tensile strain to be developed in covers. This strain could be large enough to cause cracking within a relatively brittle compacted clay. Dewatering of tailings by drainage can cause settlement even greater than that by placement of a cover material. Dewatering of the tailings would also increase the stability of the tailings surface, thereby enhancing reclamation operations. Consequently, in view of the enhanced surface stability and the fact that a portion of the differential settlement can be accomplished prior to cover placement, dewatering of tailings impoundments during operations may have benefical effects

  13. Tail posture predicts tail biting outbreaks at pen level in weaner pigs

    DEFF Research Database (Denmark)

    Lahrmann, Helle Pelant; Hansen, Christian Fink; D'Eath, Rick

    2018-01-01

    posture and behaviour could be detected at pen level between upcoming tail biting pens (T-pens) and control pens (C-pens). The study included 2301 undocked weaner pigs in 74 pens (mean 31.1 pigs/pen; SD 1.5). Tails were scored three times weekly (wound freshness, wound severity and tail length) between 07......Detecting a tail biting outbreak early is essential to reduce the risk of pigs getting severe tail damage. A few previous studies suggest that tail posture and behavioural differences can predict an upcoming outbreak. The aim of the present study was therefore to investigate if differences in tail......:00 h-14:00 h from weaning until a tail biting outbreak. An outbreak (day 0) occurred when at least four pigs had a tail damage, regardless of wound freshness. On average 7.6 (SD 4.3) pigs had a damaged tail (scratches + wound) in T-pens on day 0. Tail posture and behaviour (activity, eating...

  14. Quartz-pebble-conglomerate gold deposits: Chapter P in Mineral deposit models for resource assessment

    Science.gov (United States)

    Taylor, Ryan D.; Anderson, Eric D.

    2018-05-17

    Quartz-pebble-conglomerate gold deposits represent the largest repository of gold on Earth, largely due to the deposits of the Witwatersrand Basin, which account for nearly 40 percent of the total gold produced throughout Earth’s history. This deposit type has had a controversial history in regards to genetic models. However, most researchers conclude that they are paleoplacer deposits that have been modified by metamorphism and hydrothermal fluid flow subsequent to initial sedimentation.The deposits are found exclusively within fault-bounded depositional basins. The periphery of these basins commonly consists of granite-greenstone terranes, classic hosts for lode gold that source the detrital material infilling the basin. The gold reefs are typically located along unconformities or, less commonly, at the top of sedimentary beds. Large quartz pebbles and heavy-mineral concentrates are found associated with the gold. Deposits that formed prior to the Great Oxidation Event (circa 2.4 giga-annum [Ga]) contain pyrite, whereas younger deposits contain iron oxides. Uranium minerals and hydrocarbons are also notable features of some deposits.Much of the gold in these types of deposits forms crystalline features that are the product of local remobilization. However, some gold grains preserve textures that are undoubtedly of detrital origin. Other heavy minerals, such as pyrite, contain growth banding that is truncated along broken margins, which indicates that they were transported into place as opposed to forming by in situ growth in a hydrothermal setting.The ore tailings associated with these deposits commonly contain uranium-rich minerals and sulfides. Oxidation of the sulfides releases sulfuric acid and mobilizes various metals into the environment. The neutralizing potential of the tailings is minimal, since carbonate minerals are rare. The continuity of the tabular ore bodies, such as those of the Witwatersrand Basin, has allowed these mines to be the deepest in

  15. Carbonate deposition on tail feathers of ruddy ducks using evaporation ponds

    Science.gov (United States)

    Euliss, N.H.; Jarvis, R.L.; Gilmer, D.S.

    1989-01-01

    Substantial carbonate deposits were observed on rectrices of Ruddy Ducks (Oxyura jamaicensis) collected during 1982-1984 on evaporation ponds in the San Joaquin Valley, California. Carbonate deposits were composed of about 75% aragonite and 25% calcite, both polymorphous forms of CaCO3. Significantly more carbonate deposits were observed on Ruddy Ducks as length of exposure to agricultural drain water increased, during the 1983-1984 field season when salt concentrations in the ponds were higher, and in certain evaporation-pond systems.

  16. Tail gut cyst.

    Science.gov (United States)

    Rao, G Mallikarjuna; Haricharan, P; Ramanujacharyulu, S; Reddy, K Lakshmi

    2002-01-01

    The tail gut is a blind extension of the hindgut into the tail fold just distal to the cloacal membrane. Remnants of this structure may form tail gut cyst. We report a 14-year-old girl with tail gut cyst that presented as acute abdomen. The patient recovered after cyst excision.

  17. Environmental Characteristics of Carbonatite and Alkaline Intrusion-related Rare Earth Element (REE) Deposits

    Science.gov (United States)

    Seal, R. R., II; Piatak, N. M.

    2017-12-01

    Carbonatites and alkaline intrusions are important sources of REEs. Environmental risks related to these deposit types have been assessed through literature review and evaluation of the geochemical properties of representative samples of mill tailings and their leachates. The main ore mineral in carbonatite deposits is bastnasite [(Ce,La)(CO3)F], which is found with dolomite and calcite ( 65 %), barite (20 - 25 %), plus a number of minor accessory minerals including sulfides such as galena and pyrite. Generally, alkaline intrusion-related REE deposits either occur in layered complexes or with dikes and veins cutting alkaline intrusions. Such intrusions have a more diverse group of REE ore minerals that include fluorcarbonates, oxides, silicates, and phosphates. Ore also can include minor calcite and iron (Fe), lead (Pb), and zinc (Zn) sulfides. The acid-generating potential of both deposit types is low because of a predominance of carbonate minerals in the carbonatite deposits, the presence of feldspars and minor calcite in alkaline intrusion-related deposits, and to only minor to trace occurrence of potentially acid-generating sulfide minerals. Both deposit types, however, are produced by igneous and hydrothermal processes that enrich high-field strength, incompatible elements, which typically are excluded from common rock-forming minerals. Elements such as yttrium (Y), niobium Nb), zirconium (Zr), hafnium (Hf), tungsten (W), titanium (Ti), tantalum (Ta), scandium (Sc), thorium (Th), and uranium (U) can be characteristic of these deposits and may be of environmental concern. Most of these elements, including the REEs, but with the exception of U, have low solubilities in water at the near-neutral pH values expected around these deposits. Mill tailings from carbonatite deposits can exceed residential soil and sediment criteria for Pb, and leachates from mill tailings can exceed drinking water guidelines for Pb. The greatest environmental challenges, however, are

  18. Recovery of uranium from Cu-flotation tails

    International Nuclear Information System (INIS)

    Jayaram, K.M.V.; Sankaran, R.N.; Dwivedy, K.K.

    1984-01-01

    Uranium occurs along with copper in several parts of India. Since the total contained uranium in some of these deposits is very large, detailed studies were carried out on samples of ore obtained from Surda, Mosabani and Rakha Cu-flotation tails analysing 0.014 per cent, 0.010 per cent and 0.011 per cent U 3 O 8 and 0.12 per cent 0.09 per cent and 0.11 per cent Cu respectively. Uranium in these samples occurs not only as free uraninite but is also associated with other minerals like apatite, magnetite, tourmaline and micas, formed at different stages of paragenitic sequence. The size also varies considerably. Because of this the recovery of uranium varied from 35 to 70 per cent by wet gravity separation of the feed. Since uranium has to be anyway extracted from these concentrates by hydrometallurgical processing, it is suggested that Cu-flotation tails may be treated by hydrometallurgy to increase the ultimate recovery. (author)

  19. Mineralogical and geochemical characterization of the Old Tailings Dam, Australia: Evaluating the effectiveness of a water cover for long-term AMD control

    International Nuclear Information System (INIS)

    Jackson, Laura M.; Parbhakar-Fox, Anita

    2016-01-01

    Establishing a shallow water cover over tailings deposited in a designated storage facility is one option to limit oxygen diffusion and retard oxidation of sulfides which have the potential to form acid mine drainage (AMD). The Old Tailings Dam (OTD) located at the Savage River mine, western Tasmania contains 38 million tonnes of pyritic tailings deposited from 1967 to 1982, and is actively generating AMD. The OTD was constructed on a natural gradient, resulting in sub-aerial exposure of the southern area, with the northern area under a natural water cover. This physical contrast allowed for the examination of tailings mineralogy and geochemistry as a function of water cover depth across the OTD. Tailings samples (n = 144, depth: ≤ 1.5 m) were collected and subjected to a range of geochemical and mineralogical evaluations. Tailings from the southern and northern extents of the OTD showed similar AMD potential based on geochemical (NAG pH range: 2.1 to 4.2) and bulk mineralogical parameters, particularly at depth. However, sulfide alteration index (SAI) assessments highlighted the microscale contrast in oxidation. In the sub-aerial zone pyrite grains are moderately oxidized to a depth of 0.3 m (maximum SAI of 6/10), under both gravel fill and oxidized covers, with secondary minerals (e.g., ferrihydrite and goethite) developed along rims and fractures. Beneath this, mildly oxidized pyrite is seen in fresh tailings (SAI = 2.9/10 to 5.8/10). In the sub-aqueous zone, the degree of pyrite oxidation demonstrates a direct relationship with cover depth, with unoxidized, potentially reactive tailings identified from 2.5 m, directly beneath an organic-rich sediment layer (SAI = 0 to 1/10). These findings are broadly similar to other tailings storage facilities e.g., Fox Lake, Sherritt-Gordon Zn−Cu mine, Canada and Stekenjokk mine, Sweden where water covers up to 2 m have successfully reduced AMD. Whilst geotechnical properties of the OTD restrict the extension

  20. The significance of natural ground-water recharge in site selection for mill tailings disposal

    International Nuclear Information System (INIS)

    Stephens, D.B.

    1985-01-01

    Milling operations throughout the world have created vast amounts of waste by-products, or tailings, which are often disposed on the land surface. The wastes may be disposed behind dams, on untreated ground, or on compacted clay or synthetic liners of impoundments and trenches. Often one of the principle concerns of environmental regulatory agencies is whether seepage from the waste pile could move through the vadose zone to the water table and possibly contaminate an aquifer. The seepage may be generated by the drainage of liquids initially deposited along with the tailings or by infiltrating meteoric water which leaches soluted from the tailings. The purpose of this article is to discuss some of the commonly held assumptions regarding storage of seepage wastes in the unsaturated zone. The significance of recent studies of water movement in dry climates which pertain to tailings site selection are presented

  1. Methanogenic biodegradation of paraffinic solvent hydrocarbons in two different oil sands tailings.

    Science.gov (United States)

    Mohamad Shahimin, Mohd Faidz; Siddique, Tariq

    2017-04-01

    Microbial communities drive many biogeochemical processes in oil sands tailings and cause greenhouse gas emissions from tailings ponds. Paraffinic solvent (primarily C 5 -C 6 ; n- and iso-alkanes) is used by some oil sands companies to aid bitumen extraction from oil sands ores. Residues of unrecovered solvent escape to tailings ponds during tailings deposition and sustain microbial metabolism. To investigate biodegradation of hydrocarbons in paraffinic solvent, mature fine tailings (MFT) collected from Albian and CNRL ponds were amended with paraffinic solvent at ~0.1wt% (final concentration: ~1000mgL -1 ) and incubated under methanogenic conditions for ~1600d. Albian and CNRL MFTs exhibited ~400 and ~800d lag phases, respectively after which n-alkanes (n-pentane and n-hexane) in the solvent were preferentially metabolized to methane over iso-alkanes in both MFTs. Among iso-alkanes, only 2-methylpentane was completely biodegraded whereas 2-methylbutane and 3-methylpentane were partially biodegraded probably through cometabolism. 16S rRNA gene pyrosequencing showed dominance of Anaerolineaceae and Methanosaetaceae in Albian MFT and Peptococcaceae and co-domination of "Candidatus Methanoregula" and Methanosaetaceae in CNRL MFT bacterial and archaeal communities, respectively, during active biodegradation of paraffinic solvent. The results are important for developing future strategies for tailings reclamation and management of greenhouse gas emissions. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Tailings transport and deposition downstream of the Northern Hercules (Moline) mine in the catchment of the Mary River, Northern Territory

    International Nuclear Information System (INIS)

    Cull, R.F.; East, T.J.; Marten, R.; Murray, A.S.; Duggan, K.

    1986-01-01

    Milling of uraniferous and other metalliferous ores at the Northern Hercules (Moline) Mine near Pine Creek produced some 246,000 tonnes of tailings between 1959 and the closure of the mill in 1972. During this period tailings were contained by several bunds which later failed resulting in the erosion and transport of tailings by tributaries of the Mary River. Suspended sediment concentrations as high as 94 g/L were recorded in Tailings Creek immediately downstream of the eroding tailings pile during the 1984/85 wet season and the total yield was equivalent to a mean erosion rate for the tailings area of 4 mm/yr. This erosion rate is about two orders of magnitude higher than natural rates in the Pine Creek area. Erosion rates of the tailings pile have, however, decreased perhaps by as much as a factor of eight since the last bund was breached. Radioactive dose rates recorded along a series of transects across floodplains downstream of the mill are consistently related to the sedimentary environment. The main channel is associated with low dose rates, and the relatively low energy environments of backswamps and flood bypass channels are characterised by higher dose rates. Longitudinally, dose rates on the floodplain generally decrease with distance downstream although the rate of decrease is not constant, and appears to be dependent upon the hydrological and geomorphic character of the catchment

  3. Uranium Mill Tailings Management

    International Nuclear Information System (INIS)

    Nelson, J.D.

    1982-01-01

    This book presents the papers given at the Fifth Symposium on Uranium Mill Tailings Management. Advances made with regard to uranium mill tailings management, environmental effects, regulations, and reclamation are reviewed. Topics considered include tailings management and design (e.g., the Uranium Mill Tailings Remedial Action Project, environmental standards for uranium mill tailings disposal), surface stabilization (e.g., the long-term stability of tailings, long-term rock durability), radiological aspects (e.g. the radioactive composition of airborne particulates), contaminant migration (e.g., chemical transport beneath a uranium mill tailings pile, the interaction of acidic leachate with soils), radon control and covers (e.g., radon emanation characteristics, designing surface covers for inactive uranium mill tailings), and seepage and liners (e.g., hydrologic observations, liner requirements)

  4. More tail lesions among undocked than tail docked pigs in a conventional herd

    DEFF Research Database (Denmark)

    Lahrmann, H. P.; Busch, M. E.; D'Eath, R. B.

    2017-01-01

    The vast majority of piglets reared in the European Union (EU) and worldwide is tail docked to reduce the risk of being tail bitten, even though EU animal welfare legislation bans routine tail docking. Many conventional herds experience low levels of tail biting among tail docked pigs, however...

  5. FARADAY ROTATION IN THE TAIL OF THE PLANETARY NEBULA DeHt 5

    International Nuclear Information System (INIS)

    Ransom, R. R.; Kothes, R.; Wolleben, M.; Landecker, T. L.

    2010-01-01

    We present 1420 MHz polarization images of a 5 0 x 5 0 region around the planetary nebula (PN) DeHt 5. The images reveal narrow Faraday-rotation structures on the visible disk of DeHt 5, as well as two wider, tail-like, structures 'behind' DeHt 5. Though DeHt 5 is an old PN known to be interacting with the interstellar medium (ISM), a tail has not previously been identified for this object. The innermost tail is ∼3 pc long and runs away from the northeast edge of DeHt 5 in a direction roughly opposite that of the sky-projected space velocity of the white dwarf central star, WD 2218+706. We believe this tail to be the signature of ionized material ram-pressure stripped and deposited downstream during a >74,000 yr interaction between DeHt 5 and the ISM. We estimate the rotation measure (RM) through the inner tail to be -15 ± 5 rad m -2 , and, using a realistic estimate for the line-of-sight component of the ISM magnetic field around DeHt 5, derive an electron density in the inner tail of n e = 3.6 ± 1.8 cm -3 . Assuming the material is fully ionized, we estimate a total mass in the inner tail of 0.68 ± 0.33 M sun and predict that 0.49 ± 0.33 M sun was added during the PN-ISM interaction. The outermost tail consists of a series of three roughly circular components, which have a collective length of ∼11.0 pc. This tail is less conspicuous than the inner tail and may be the signature of the earlier interaction between the WD 2218+706 asymptotic giant branch (AGB) progenitor and the ISM. The results for the inner and outer tails are consistent with hydrodynamic simulations and may have implications for the PN missing-mass problem as well as for models which describe the impact of the deaths of intermediate-mass stars on the ISM.

  6. Assessment of the microbial populations in field and test pit experiments at Elliot Lake, Ontario, Canada

    International Nuclear Information System (INIS)

    Silver, M.; Taylor, J.B.

    1981-01-01

    Enumeration of aerobic and anaerobic heterotrophic (organic carbon-using) bacteria shows the establishment of a microbial population on vegetated tailings. The development of a population of heterotrophic bacteria, 90% of which are obligate aerobes, in the top 5 cm of the tailings is indicative of normal soil formation. The cell concentration decrease is greater than that found in older, well-developed soils. Iron-oxidizing thiobacilli are rarely present in the revegetated tailings, and then only at depths below 40 cm and at cell concentrations less than 100 cells/g. On an adjacent unvegetated portion of the tailings, fewer heterotrophic bacteria are found in the top 5 cm of the tailings. Iron-oxidizing thiobacilli are present uniformly in the top 47 cm. Enumeration of iron-oxidizing bacteria in the effluents of four test pit experiments indicate blockage of the drainage tiles in two experiments. Chemical conditions of the effluents are suitable for the formation of basic ferric precipitates that could cause this blockage

  7. Conditions required for opening of a commercial mineral deposit

    International Nuclear Information System (INIS)

    Shastry, S.

    1991-01-01

    It has been observed that once a mineral deposit is discovered and ore reserves are estimation, it is presumed that the deposit is commercially exploitable. Estimation of ore reserves, alone is not sufficient to consider a deposit exploitable. There are many more investigation necessary to make a deposit commercially mineable. Data regarding rock characteristics, behaviour of the ore body, hydrological conditions, extraction properties of ore, disposal of mine water and waste rock and suitable sites for mill tailings disposal, are required to be collected for assessing the opening of a new deposit. In this paper all these conditions are discussed

  8. Oil sands thickened froth treatment tailings exhibit acid rock drainage potential during evaporative drying.

    Science.gov (United States)

    Kuznetsov, Petr; Kuznetsova, Alsu; Foght, Julia M; Siddique, Tariq

    2015-02-01

    Bitumen extraction from oil sands ores after surface mining produces different tailings waste streams: 'froth treatment tailings' are enriched in pyrite relative to other streams. Tailings treatment can include addition of organic polymers to produce thickened tailings (TT). TT may be further de-watered by deposition into geotechnical cells for evaporative drying to increase shear strength prior to reclamation. To examine the acid rock drainage (ARD) potential of TT, we performed predictive analyses and laboratory experiments on material from field trials of two types of thickened froth treatment tailings (TT1 and TT2). Acid-base accounting (ABA) of initial samples showed that both TT1 and TT2 initially had net acid-producing potential, with ABA values of -141 and -230 t CaCO₃ equiv. 1000 t(-1) of TT, respectively. In long-term kinetic experiments, duplicate ~2-kg samples of TT were incubated in shallow trays and intermittently irrigated under air flow for 459 days to simulate evaporative field drying. Leachates collected from both TT samples initially had pH~6.8 that began decreasing after ~50 days (TT2) or ~250 days (TT1), stabilizing at pH~2. Correspondingly, the redox potential of leachates increased from 100-200 mV to 500-580 mV and electrical conductivity increased from 2-5 dS m(-1) to 26 dS m(-1), indicating dissolution of minerals during ARD. The rapid onset and prolonged ARD observed with TT2 is attributed to its greater pyrite (13.4%) and lower carbonate (1.4%) contents versus the slower onset of ARD in TT1 (initially 6.0% pyrite and 2.5% carbonates). 16S rRNA gene pyrosequencing analysis revealed rapid shift in microbial community when conditions became strongly acidic (pH~2) favoring the enrichment of Acidithiobacillus and Sulfobacillus bacteria in TT. This is the first report showing ARD potential of TT and the results have significant implications for effective management of pyrite-enriched oil sands tailings streams/deposits. Copyright © 2014

  9. Presentations of the CONRAD tailings seminar : exploring the past, present and future of tailings technologies

    International Nuclear Information System (INIS)

    2004-01-01

    This symposium explored oil sand tailings activities in Canada and their associated technologies. It was attended by active and prospective tailings researchers and developers of tailings technology who addressed timely issues regarding mature fine tailings, consolidated tailings, thickened tailings, and emerging tailings technologies. The collaborative research projects that are underway at the Oil Sands Tailings Research Facility were also discussed along with other topics such as tailings ponds management, water treatment, water quality and water supply security. All 16 presentations featured at this conference were indexed separately for inclusion in this database

  10. Galaxies with long tails

    International Nuclear Information System (INIS)

    Schweizer, F.

    1978-01-01

    Two types of galaxies with long tails are described. The first occurs in pairs, each individual one having a long tail and the second occurs on its own with two tails. NGC 7252 shows several characteristics which one would expect of a merger: a pair of tidal tails despite the splendid isolation, a single nucleus, tail motions in opposite directions relative to the nucleus, and chaotic motions of a strangely looped main body. (C.F.)

  11. Long-term fate and transport of arsenic in an in-pit uranium mine tailings facility

    International Nuclear Information System (INIS)

    Moldovan, B.; Hendry, M.J.

    2006-01-01

    An important environmental issue facing the uranium mining industry in Saskatchewan is the quantification of the long-term migration of arsenic from its tailings facilities to the adjacent groundwater system. Decommissioning of these arsenic-rich tailings requires that the long-term arsenic source term for the tailings to the groundwater be defined. To meet this need, arsenic-rich uranium mine tailings from one in-pit tailings facility (tailings emplaced in a mined out open pit) were studied in detail. The tailings facility selected for study was the Rabbit Lake in-pit tailings management facility (RLITMF) in northern Saskatchewan, Canada. The tailings body in the RLITMF is 425 m long x 300 m wide x 100 m deep at its center and mill tailings were deposited in layers between 1985 (base) and 2004 (top). Associated with the low-level radioactive tailings is approximately 23,000 tonnes of arsenic. The in-pit design limits solute transport in these fine-grained tailings to diffusion. Because the layers of tailings have varying chemical characteristics (controlled by the ore being milled at the time), the total arsenic concentrations in the layers and their associated pore fluids range from 56 to 9,871 μ/g and 0.24 to 140 mg/l, respectively. As was the case for arsenic, the concentration of iron present in the layers was also variable (ranging from 8,967 to 30,247 μ/g). Synchrotron-based studies show that the arsenic in these tailings is strongly attenuated by adsorption to secondary 2-line ferrihydrite through inner sphere bidentate linkages. Single reservoir diffusion cell testing shows that the effective diffusion coefficient for arsenic in the tailings is 4.5 x 10 -10 m 2 s- 1 . Based on results from our field- and laboratory-based studies, the redistribution (via diffusion) and attenuation (via adsorption) of arsenic in the RLITMF was modelled using a one-dimensional geochemical reactive transport model to provide a source term for arsenic migration from the

  12. Attitudes of Dutch Pig Farmers Towards Tail Biting and Tail Docking

    OpenAIRE

    Bracke, M.B.M.; Lauwere, de, C.C.; Wind, S.M.M.; Zonderland, J.J.

    2013-01-01

    The Dutch policy objective of a fully sustainable livestock sector without mutilations by 2023 is not compatible with the routine practice of tail docking to minimize the risk of tail biting. To examine farmer attitudes towards docking, a telephone survey was conducted among 487 conventional and 33 organic Dutch pig farmers. “Biting” (of tails, ears, or limbs) was identified by the farmers as a main welfare problem in pig farming. About half of the farmers reported to have no tail biting prob...

  13. Sinterization of manganese ore tailings under natural air

    Energy Technology Data Exchange (ETDEWEB)

    Lima, M.M.F.; Souza, L.G.P.R.M.F. [Universidade Federal de Ouro Preto (UFOP), MG (Brazil)

    2014-07-01

    The manganese ore has wide application in metallurgy. However, from each of three hundred concentrations found, only one can be seen as a deposit. The aim of this study was to obtain and characterize a sinter from manganese ore tailing. The tailing was milled, classified (<400 ⧣) and calcinated (800°C - 3600s). The mixture had 12% moisture, 7 and 9% of activated charcoal. After homogenization, the sintering were carried out at 1140, 1145 and 1150°C during 1800, 7200 and 14400s at natural air. The sintered products were characterized by EDS analysis, BET surface area, apparent density, X-rays diffraction and SEM/EDS. The mass loss was approximately 14% and 16% in the calcination and sintering, respectively, due to the elimination of volatile products and water. The main phases characterized: SiO2, silicate with high content of manganese in the matrix and other silicates with different proportions of Ti, Na, Mn, Mg and Ca. (author)

  14. About necessity of remediation and re-cultivation of Taboshar districts' tailings

    International Nuclear Information System (INIS)

    Salomov, J.A.; Mirsaidov, I.U.; Barotov, A.M.

    2012-01-01

    Taboshar uranium deposit is one of the oldest sites of uranium industry and reprocessing in former USSR. During geological survey in 1926 close to Istiklol city (former Taboshar), relatively high radioactivity was revealed on present territory and in 1927 the physical exploration of uranium-containing zones was completed. Active extraction of ore was carried out here from 1945 till 1965 y. Nowadays it is a huge territory with total area of more than 400 hectares covered by surface wastes tailings of hydrometallurgical reprocessing of uranium ores. Disposal complex consists from non-preserved open pit ('Factory of barren ores'), destroyed industrial buildings and four tailings (Tailing I-II, Tailing III, Tailing IV and tailing of industrial workshop 3), containing approximately 55 million tons of wastes, from which approximately 12 million tons are uranium ore's wastes. Total area of four tailing and 'Factory of barren ores' is 63 hectares. Besides, balanced-off ores and overburden rocks i.e. ores and rocks unprofitable for reprocessing should be included here as well. Factor analysis of radiation danger carried out by IAEA expert mission in Istiklol city revealed that radon content in air and aerosol contamination is not a factor of considerable radiation risk for city residents, besides cases of their visit to tailings and living of people directly within zones of their location since territory is well aired out. However, due to bad coverage of tailing, drainage waters draining from zones of their location are highly contaminated by radionuclides and contain high concentrations of manganese, sodium, lead and iron. Drainage waters of former flooded uranium mines and open pits are also considerably contaminated. Such contaminated waters are used all over by local population for cattle watering, watering of garden territories and even for drinking. Thus, the use of drainage and mine waters with high contamination level for drinking and household needs in Istiklol

  15. Recovery and Purification of Tin from Tailings from the Penouta Sn–Ta–Nb Deposit

    Directory of Open Access Journals (Sweden)

    Félix Antonio López

    2018-01-01

    Full Text Available A concentrate obtained from mining tailings containing mainly cassiterite and columbotantalite was reduced for the production of tin metal. The compounds CaCO3, Na2CO3, K2CO3, and borax were used as fluxes in the pyrometallurgical reduction smelting process, and graphite was employed as the reducing agent. The greatest recovery of Sn (>95% was obtained when using CaCO3 as the flux; the purity of Sn was 96%. A slag equivalent to 25% of the mass of the initial concentrate was produced during the recovery of the Sn. This contained 45% Nb2O5 and Ta2O5, adding extra value to the mine tailings. The tin metal ingot was purified by electrorefining involving a tin and H2SO4 electrolyte solution and a 101.9 A/m2 current applied for 148 h. Under these conditions, 90 wt % of the Sn in the ingot was recovered at a purity of 99.97%.

  16. Application of a Method for Intelligent Multi-Criteria Analysis of the Environmental Impact of Tailing Ponds in Northern Kosovo and Metohija

    Directory of Open Access Journals (Sweden)

    Gordana Milentijević

    2016-11-01

    Full Text Available The technological process of exploitation of mineral resources and processing of mined ores to cater to the market results, among other things, in a large amount of tailings deposed on tailing ponds. Because of the chemical composition of the material, the increasing amount of waste, and the mismanagement of recovery and reclamation of ponds, these ponds have become a significant element of negative impact on the surrounding ecosystem. Economics was behind the discharging of this material, resulting in tailing ponds created in inappropriate areas. There is an ongoing process of depositing tailings on old tailing ponds, although no special attention has been paid to the subsequent effect on the environment. Application of intelligent multi-criteria analysis AHP and PROMETHEE has been performed in this paper for the purpose of ranking the degree of negative impact on the environment of tailing ponds. Analysis is performed for five tailing ponds of MMCC (Mining Metallurgy Chemical Combine “Trepča”, whereby two of the ponds are active and three inactive. The ponds are in relatively close proximity to the municipalities of Zvečan and Kosovska Mitrovica, to the north of Kosovo and Metohija, Republic of Serbia. In order to achieve the most objective results, the AHP and PROMETHEE methods were applied. By using these methods for calculations, the following ranking for the flotation tailing waste deposits was obtained, regarding their environmental impact: Žitkovac, Tvrđanski Do, Bostanište, Gornje Polje and Žarkov Potok. This result can contribute to the decision-making process of a prioritizing strategy for rehabilitation and remediation of these five flotation tailings. The analysis illustrates that application of intelligent multi-criteria analysis is a useful environmental management tool to be included in the decision-making process.

  17. Shear strength, consolidation and drainage of colliery tailings lagoons

    Energy Technology Data Exchange (ETDEWEB)

    Kirby, J M

    1980-01-01

    The shear strength and consolidation characteristics of colliery tailings were related to the structure of the lagoon deposits. First, a theoretical investigation of vane shear tests in layered media is outlined, and then cone penetration tests are considered as an alternative tool for measuring strengths in situ. The geochemistry and sedimentology of colliery lagoons were investigated. The in-situ permeability of lagoons was also investigated and the results used to investigate the drainage characteristics. Finally, overtipping was investigated.

  18. Screening Assessment of Radionuclide Migration in Groundwater from the “Dneprovskoe” Tailings Impoundment (Dneprodzerzhynsk City) and Evaluation of Remedial Options

    Energy Technology Data Exchange (ETDEWEB)

    Skalskyi, O.; Bugai, D. [Institute of Geological Sciences, National Academy of Sciences of Ukraine (Ukraine); Ryazantsev, V. [State Nuclear Regularity Committee of Ukraine, Kiev (Ukraine)

    2014-05-15

    The paper presents results of mathematical modeling of the hydrogeological conditions at the “Dneprovskoe” (“D”) tailings impoundment –object of the former industrial association of “Pridneprovsky Chemical Plant”, which contains uranium ore processing wastes. This radioactively polluted site is located in a densely populated region (at the outskirts of Dneprodzerginsk City) near the major watercourse of the Ukraine — Dnieper River.The mathematical modeling utilized Visual Modflow (for groundwater flow) and Ecolego (Facilia AB, Sweden) radioecology modeling software (for radionuclide transport).Modeling results indicate the possibility of essential radioactive contamination in future of the phreatic aquifer in alluvial deposits between the “D” tailings and the Dnieper River (mainly due to migration of uranium). Therefore long-term management strategies should preclude water usage from the aquifer in the zone of the in-fluence of the “D” tailings. Filtration discharge of uranium to the Dnepr River does not represent a significant risk due to large dilution by surface waters. The important modeling conclusion is that besides the uranium ore processing wastes inside the tailings, the major source of radionuclide migration to groundwater is represented by contaminated geological deposits below the tailings. This last source was formed due to leakage of wastewaters during the operational period of the “D” tailings (1954–1968). Therefore an exemption and re-disposal of wastes from the “D” tailings to a more safe storage location (proposed by some remedial plans) will not provide significant benefit from the viewpoint of minimizing of radionuclide transport to the groundwater and Dnieper River (especially in short-and medium-term perspective). The rational remedial strategy for the “D” tailings is conservation of tailing wastes in-situ by means of specially designed “zero flux” soil screen, which would minimize infiltration of

  19. Microbial diversity at the moderate acidic stage in three different sulfidic mine tailings dumps generating acid mine drainage.

    Science.gov (United States)

    Korehi, Hananeh; Blöthe, Marco; Schippers, Axel

    2014-11-01

    In freshly deposited sulfidic mine tailings the pH is alkaline or circumneutral. Due to pyrite or pyrrhotite oxidation the pH is dropping over time to pH values tailings are only scarcely studied. Here we investigated the microbial diversity via 16S rRNA gene sequence analysis in eight samples (pH range 3.2-6.5) from three different sulfidic mine tailings dumps in Botswana, Germany and Sweden. In total 701 partial 16S rRNA gene sequences revealed a divergent microbial community between the three sites and at different tailings depths. Proteobacteria and Firmicutes were overall the most abundant phyla in the clone libraries. Acidobacteria, Actinobacteria, Bacteroidetes, and Nitrospira occurred less frequently. The found microbial communities were completely different to microbial communities in tailings at

  20. Bar-tailed

    NARCIS (Netherlands)

    Duijns, S.; Hidayati, N.A.; Piersma, T.

    2013-01-01

    Capsule Across the European wintering range Bar-tailed Godwits Limosa lapponica lapponica selected polychaete worms and especially Ragworms Hediste diversicolor, with differences between areas due to variations in prey availability.Aims To determine the diet of Bar-tailed Godwits across their

  1. TAIL ASYMPTOTICS OF LIGHT-TAILED WEIBULL-LIKE SUMS

    DEFF Research Database (Denmark)

    Asmussen, Soren; Hashorva, Enkelejd; Laub, Patrick J.

    2017-01-01

    We consider sums of n i.i.d. random variables with tails close to exp{-x(beta)} for some beta > 1. Asymptotics developed by Rootzen (1987) and Balkema, Kluppelberg, and Resnick (1993) are discussed from the point of view of tails rather than of densities, using a somewhat different angle...

  2. Effects of weather and tailings properties on tailings drying times

    Energy Technology Data Exchange (ETDEWEB)

    Gantzer, C.; Fasking, T.; Costello, M.; Greenwood, J. [Barr Engineering, Calgary, AB (Canada)

    2010-07-01

    This PowerPoint presentation presented the results of a study conducted to determine the effects of weather and tailings properties on tailings drying times. Weather conditions have a significant impact the potential evaporation (PE) and actual evaporation (AE) of oil sands tailings. A 2-stage drying of slurry at a constant PE was conducted to determine the shrinkage limit of untreated mature fine tailings (MFT). An evaporation and seepage model was used to determine maximum first-stage drying rates. Measurements were also taken in a wind tunnel. Potential evaporation rates were calculated and evaporative water losses from the MFT were determined. Estimated drying times were presented. Results of the approach were compared with field measurements conducted in a previous study. Results of the study showed that evaporative water loss rates for May through August were limited by the properties of the tailings. Water loss rates were limited by weather for other months in the year-long study. tabs., figs.

  3. Uranium tailings sampling manual

    International Nuclear Information System (INIS)

    Feenstra, S.; Reades, D.W.; Cherry, J.A.; Chambers, D.B.; Case, G.G.; Ibbotson, B.G.

    1985-01-01

    The purpose of this manual is to describe the requisite sampling procedures for the application of uniform high-quality standards to detailed geotechnical, hydrogeological, geochemical and air quality measurements at Canadian uranium tailings disposal sites. The selection and implementation of applicable sampling procedures for such measurements at uranium tailings disposal sites are complicated by two primary factors. Firstly, the physical and chemical nature of uranium mine tailings and effluent is considerably different from natural soil materials and natural waters. Consequently, many conventional methods for the collection and analysis of natural soils and waters are not directly applicable to tailings. Secondly, there is a wide range in the physical and chemical nature of uranium tailings. The composition of the ore, the milling process, the nature of tailings depositon, and effluent treatment vary considerably and are highly site-specific. Therefore, the definition and implementation of sampling programs for uranium tailings disposal sites require considerable evaluation, and often innovation, to ensure that appropriate sampling and analysis methods are used which provide the flexibility to take into account site-specific considerations. The following chapters describe the objective and scope of a sampling program, preliminary data collection, and the procedures for sampling of tailings solids, surface water and seepage, tailings pore-water, and wind-blown dust and radon

  4. Soil erosion and deposition in the new shorelines of the Three Gorges Reservoir.

    Science.gov (United States)

    Su, Xiaolei; Nilsson, Christer; Pilotto, Francesca; Liu, Songping; Shi, Shaohua; Zeng, Bo

    2017-12-01

    During the last few decades, the construction of storage reservoirs worldwide has led to the formation of many new shorelines in former upland areas. After the formation of such shorelines, a dynamic phase of soil erosion and deposition follows. We explored the factors regulating soil dynamics in the shorelines of the Three Gorges Reservoir (TGR) on the Yangtze River in China. We selected four study sites on the main stem and three on the tributaries in the upstream parts of the reservoir, and evaluated whether the sites close to the backwater tail (the point at which the river meets the reservoir) had more soil deposition than the sites far from the backwater tail. We also tested whether soil erosion differed between the main stem and the tributaries and across shorelines. We found that soil deposition in the new shorelines was higher close to the backwater tail and decreased downstream. Soil erosion was higher in the main stem than in the tributaries and higher at lower compared to higher shoreline altitudes. In the tributaries, erosion did not differ between higher and lower shoreline levels. Erosion increased with increasing fetch length, inundation duration and distance from the backwater tail, and decreased with increasing soil particle fineness. Our results provide a basis for identifying shorelines in need of restorative or protective measures. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Chemistry of Selected Core Samples, Concentrate, Tailings, and Tailings Pond Waters: Pea Ridge Iron (-Lanthanide-Gold) Deposit, Washington County, Missouri

    Science.gov (United States)

    Grauch, Richard I.; Verplanck, Philip L.; Seeger, Cheryl M.; Budahn, James R.; Van Gosen, Bradley S.

    2010-01-01

    The Minerals at Risk and for Emerging Technologies Project of the U.S. Geological Survey (USGS) Mineral Resources Program is examining potential sources of lanthanide elements (rare earth elements) as part of its objective to provide up-to-date geologic information regarding mineral commodities likely to have increased demand in the near term. As part of the examination effort, a short visit was made to the Pea Ridge iron (-lanthanide-gold) deposit, Washington County, Missouri in October 2008. The deposit, currently owned by Wings Enterprises, Inc. of St. Louis, Missouri (Wings), contains concentrations of lanthanides that may be economic as a primary product or as a byproduct of iron ore production. This report tabulates the results of chemical analyses of the Pea Ridge samples and compares rare earth elements contents for world class lanthanide deposits with those of the Pea Ridge deposit. The data presented for the Pea Ridge deposit are preliminary and include some company data that have not been verified by the USGS or by the Missouri Department of Natural Resources, Division of Geology and Land Survey (DGLS), Geological Survey Program (MGS). The inclusion of company data is for comparative purposes only and does not imply an endorsement by either the USGS or MGS.

  6. Impaired short-term functioning of a benthic community from a deep Norwegian Fjord following deposition of mine tailings and sediments

    NARCIS (Netherlands)

    Mevenkamp, L.; Stratmann, T.; Guilini, K.; Moodley, L.; Van Oevelen, D.; Vanreusel, A.; Westerlund, S.; Sweetman, A.K.

    2017-01-01

    The extraction of minerals from land-based mines necessitates the disposal of large amounts of mine tailings. Dumping and storage of tailings into the marine environment, such as fjords, is currently being performed without knowing the potential ecological consequences. This study investigated the

  7. Disposal of iron tailings in reservoirs: a GPR application

    Directory of Open Access Journals (Sweden)

    Rachel Jardim Martini

    2016-11-01

    Full Text Available A large volume of waste is generated by iron mining in Brazil, and the amount has been rapidly increasing. The waste is usually stored in large piles or in reservoirs formed by tailings dams, which occupy large areas in the mining complex. The limitation of natural resources and of new areas for waste disposal has led to change in paradigms. This study therefore aimed to apply a geophysical technique, known as Ground Penetrating Radar (GPR, in order to define sedimentation patterns in the subsurface reservoir created by Diogo's tailings dam in Rio Piracicaba in Minas Gerais, Brazil. To assist the recognition of patterns captured by the GPR, subsurface material samples were collected and analyzed for mineralogical composition, moisture content, electrical conductivity, mineralogical analysis, particle size, X-Ray Diffraction and X-Ray Fluorescence. The results indicated that areas with tailings that had high concentrations of hematite (around 60% in the mineralogical analysis altered the reflection patterns. The presence of water generated some multiple reflections, which were less significant in shallower sites with more waste and more significant in deeper sites with less waste. In general, the application of the GPR was feasible in aquatic environments with rich subsurface hematite deposits.

  8. Uranium mill tailings conditioning technology

    International Nuclear Information System (INIS)

    Dreesen, D.R.; Cokal, E.J.; Wangen, L.E.; Williams, J.M.; O'Brien, P.D.; Thode, E.F.

    1982-01-01

    Conditioning of uranium mill tailings involves the physicochemical alteration of tailings to remove or immobilize mobile radionuclides and toxic trace elements before disposal in a repository. The principal immobilization approach under investigation is sintering tailings at high temperatures (1100-1200 deg. C) to radically alter the structure of tailings. This thermal stabilization at 1200 deg. C reduced radon emanation power for tailings sands by factors of 20 to 200 and for tailings fines by factors of 300 to 1100. Substantial reductions in the leachability of most contaminants have been found for thermally conditioned tailings. Obvious mineral transformations occur, including an increase in amorphous material, the conversion of gypsum to anhydrite and its subsequent decomposition, the disappearance of clay minerals, and some decrease in quartz content. A conceptual thermal stabilization process has been developed wherein obsolete coal-fired rotary cement kilns perform the sintering. An economic analysis of this conceptual process has shown that thermal stabilization can be competitive at certain tailings sites with other remedial actions requiring the excavation, transportation, and burial of tailings in a repository. An analysis of the long-term radiological hazard posed by untreated tailings and by tailings conditioned by radionuclide removal has illustrated the necessity of extracting both 226 Ra and 230 Th to achieve long-term hazard reductions. Sulphuric acid extraction of residual mineral values and important radionuclides from tailings has been investigated. Concentrated H 2 SO 4 can extract up to 80% of the 226 Ra, 70% of the Ba, and 90% of the 230 Th from tailings in a single stage extraction. An economic analysis of a sulphuric acid leach process was made to determine whether the value of minerals recovered from tailings would offset the leaching cost. For one relatively mineral-rich tailings pile, the U and V values would more than pay for the

  9. Uranium tailings bibliography

    International Nuclear Information System (INIS)

    Holoway, C.F.; Goldsmith, W.A.; Eldridge, V.M.

    1975-12-01

    A bibliography containing 1,212 references is presented with its focus on the general problem of reducing human exposure to the radionuclides contained in the tailings from the milling of uranium ore. The references are divided into seven broad categories: uranium tailings pile (problems and perspectives), standards and philosophy, etiology of radiation effects, internal dosimetry and metabolism, environmental transport, background sources of tailings radionuclides, and large-area decontamination

  10. Performance Comparison between Neutralization Tailings and Flotation Tailings Used for Backfill Mix and Mechanism Analysis

    Directory of Open Access Journals (Sweden)

    Bin Han

    2016-01-01

    Full Text Available A comparison test of different tailings used for underground backfill was conducted, using neutralized tailings from BIOX and flotation tailings of Jinfeng Mine. Laboratory comparison test results show that, with neutralized tailings, when the cement dosage is at 19%, backfill UCS after 7 days, 14 days, and 28 days are 105%–163%, 80%–102%, and 33%–43%, respectively, which are higher than those of flotation tailings. When the cement dosage is at 12%, backfill UCS after 7 days, 14 days, and 28 days are 58%–77%, 50%–60%, and 28%–51%, respectively, which are higher than those of flotation tailings. Slurry fluidity of neutralized tailings is lower than that of flotation tailings, while, in these two tailings, the difference of slump and diffusivity values is less than 6%, which is not a significant difference in slurry fluidity. The reason for neutralized tailings showing higher UCS is as follows: during backfill curing, neutralization tailings produce abundant crystals of CaSO4·2H2O in interlaced structure which helps in combining aggregates closely; CaSO4·2H2O hydrates with C3A C4AF contained in the cement and forms clavate cement bacillus which works as a micro reinforcing steel bar. The test proved that neutralized tailings are more optimal for backfilling.

  11. Mineralogical characterization of arsenic, iron, and nickel in uranium mine tailings using XAS and EMPA

    International Nuclear Information System (INIS)

    Essilfie-Dughan, J.; Hendry, M.J.; Warner, J.; Kotzer, T.

    2010-01-01

    In northern Saskatchewan, Canada, high-grade uranium ores and the resulting tailings can contain high levels of arsenic (As), iron (Fe), and nickel (Ni). An environmental concern in the uranium mining industry is the long-term stabilization of these elements of concern (EOCs) within tailings management facilities thereby mitigating their transfer to the surrounding groundwater. Characterization of these As-, Fe- and Ni-bearing minerals and complexes must be carried out to evaluate their solubility and long-term stability within the tailings mass. Synchrotron-based bulk x-ray absorption spectroscopy (XAS) has been used to study the speciation of these EOCs in mine tailing samples obtained from the Deilmann Tailings Management Facility (DTMF) at Key Lake, Saskatchewan. Electron microprobe analysis (EMPA) and synchrotron-based micro-focussing x-ray fluorescence mapping and absorption spectroscopy (μXRF; μXAS ) have also been employed to study spatial distribution and speciation at the micron scale. Comparisons of K-edge absorption spectra of tailings samples and reference compounds indicate the dominant oxidation states of As, Fe, and Ni in the mine tailings samples are +5, +3, and +2, respectively, largely reflecting their deposition in an oxidized environment and complexation within stable oxic phases. Backscattered electron (BSE) images of the tailings from the electron microprobe indicate the presence of gypsum/lime nodules surrounded by metallic rims mainly consisting of As, Fe, and Ni. μXRF elemental mapping confirms these EPMA results. μXAS collected within the metal-bearing rims indicates As and Fe is present mainly in the +5 and +3 oxidation state, respectively. (author)

  12. Physical quality of bauxite tailing after a decade of environmental recovery

    Directory of Open Access Journals (Sweden)

    Lorena Abdalla de Oliveira Prata Guimarães

    Full Text Available ABSTRACT Tailings from bauxite washing produced in Porto Trombetas, Pará state, a Brazilian Amazon region, have chemical and physical characteristics limiting the development of plants, which hinders to revegetate the tanks where they are deposited. This study was carried out under field conditions, and aimed to assess the physical quality of these tailings after a decade of recovery practices. Three treatments were assessed: no application of inputs and planting of seedlings (T1 and two levels of fertilization, one with lower (T2 and other with higher (T3 doses of limestone and fertilizers associated with planting tree seedlings. After ten years of experimentation, penetration resistance (PR and substrate moisture up to 60 cm depth were assessed and the least limiting water range (LLWR, water retention curve (WRC, and pore size distribution were determined and calculated. After a decade of environmental recovery, differences in physical characteristics were observed in the tailings due to different revegetation modes. Moisture in the substrate profile, LLWR, WRC, and pore size distribution were sensitive indicators to variations in substrate physical quality. Liming, fertilization, and planting of seedlings are necessary for revegetation and improvement of the physical quality of tailings. Treatment T3 was the best intervention identified so far for tank revegetation. The absence of fertilization and planting precludes revegetation even with sources of propagules nearby.

  13. Aging simulation of the tailings from Stava fluorite extraction by exposure to gamma rays

    Directory of Open Access Journals (Sweden)

    Gianluca Bella

    Full Text Available Abstract Tailings storage facilities are disposal systems for storing the waste products of the mining industry consisting of a slurry mixture made of soil, rock and water that remain after the mineral values have been removed from the patent ore. Tailings dams are supposed to last forever, so after their deposition, tailings can experience aging processes with physical and chemical changes depending on the interactions between local conditions and source mineralogy. The consequences of these aging processes are increased interlocking of particles and oxidation processes, sometimes making previously safely held contaminants available and mobile. Among the long-term aging processes, the natural ionizing radiation (from radioactive isotopes of the soils, cosmic rays, and also ultraviolet rays from the sun can be considered, as proposed in the current research. Furthermore, in many countries, tailings are beginning to be re-used as backfill, landscaping material or feedstock for cement and concrete. So if any, the long-term physical and chemical modifications could affect the hydraulic and mechanical behaviour of tailings with relevant economic consequences. For these reasons, wet and dry silty samples of tailings spilled out after the failure of the Stava tailings dam (Trentino Alto Adige, Italy were exposed to gamma rays, as an accelerated aging technique to simulate the natural ionizing radiation, and then characterized. The modifications on physical and chemical properties were observed and, despite certain chemical stability, some physical changes were observed, particularly in terms of size particle distribution, inner porosity of the particles and specific surface.

  14. Aging simulation of the tailings from Stava fluorite extraction by exposure to gamma rays

    Energy Technology Data Exchange (ETDEWEB)

    Bella, Gianluca; Barbero, Monica; Barpi, Fabrizio, E-mail: gianluca.bella@polito.it, E-mail: monica.barbero@polito.it, E-mail: fabrizio.barpi@polito.it [Politecnico di Torino - DISEG (Italy); Lameiras, Fernando Soares, E-mail: fsl@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Espósito, Terezinha de Jesus, E-mail: esposito@etg.ufmg.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Transporte e Engenharia Geotécnica

    2017-10-15

    Tailings storage facilities are disposal systems for storing the waste products of the mining industry consisting of a slurry mixture made of soil, rock and water that remain after the mineral values have been removed from the patent ore. Tailings dams are supposed to last forever, so after their deposition, tailings can experience aging processes with physical and chemical changes depending on the interactions between local conditions and source mineralogy. The consequences of these aging processes are increased interlocking of particles and oxidation processes, sometimes making previously safely held contaminants available and mobile. Among the long-term aging processes, the natural ionizing radiation (from radioactive isotopes of the soils, cosmic rays, and also ultraviolet rays from the sun) can be considered, as proposed in the current research. Furthermore, in many countries, tailings are beginning to be re-used as backfill, landscaping material or feedstock for cement and concrete. So if any, the long-term physical and chemical modifications could affect the hydraulic and mechanical behaviour of tailings with relevant economic consequences. For these reasons, wet and dry silty samples of tailings spilled out after the failure of the Stava tailings dam (Trentino Alto Adige, Italy) were exposed to gamma rays, as an accelerated aging technique to simulate the natural ionizing radiation, and then characterized. The modifications on physical and chemical properties were observed and, despite certain chemical stability, some physical changes were observed, particularly in terms of size particle distribution, inner porosity of the particles and specific surface. (author)

  15. Bioassay for uranium mill tailings

    International Nuclear Information System (INIS)

    Tschaeche, A.N.

    1986-01-01

    Uranium mill tailings are composed of fine sand that contains, among other things, some uranium (U/sup 238/ primarily), and all of the uranium daughters starting with /sup 230/Th that are left behind after the usable uranium is removed in the milling process. Millions of pounds of tailings are and continue to be generated at uranium mills around the United States. Discrete uranium mill tailings piles exist near the mills. In addition, the tailings materials were used in communities situated near mill sites for such purposes as building materials, foundations for buildings, pipe runs, sand boxes, gardens, etc. The Uranium Mill Tailings Remedial Action Project (UMTRAP) is a U.S. Department of Energy Program designed with the intention of removing or stabilizing the mill tailings piles and the tailings used to communities so that individuals are not exposed above the EPA limits established for such tailings materials. This paper discusses the bioassay programs that are established for workers who remove tailings from the communities in which they are placed

  16. Low-fluorine Stockwork Molybdenite Deposits

    Science.gov (United States)

    Ludington, Steve; Hammarstrom, Jane; Piatak, Nadine M.

    2009-01-01

    Low-fluorine stockwork molybdenite deposits are closely related to porphyry copper deposits, being similar in their tectonic setting (continental volcanic arc) and the petrology (calc-alkaline) of associated igneous rock types. They are mainly restricted to the Cordillera of western Canada and the northwest United States, and their distribution elsewhere in the world may be limited. The deposits consist of stockwork bodies of molybdenite-bearing quartz veinlets that are present in and around the upper parts of intermediate to felsic intrusions. The deposits are relatively low grade (0.05 to 0.2 percent Mo), but relatively large, commonly >50 million tons. The source plutons for these deposits range from granodiorite to granite in composition; the deposits primarily form in continental margin subduction-related magmatic arcs, often concurrent with formation of nearby porphyry copper deposits. Oxidation of pyrite in unmined deposits or in tailings and waste rock during weathering can lead to development of acid-rock drainage and limonite-rich gossans. Waters associated with low-fluorine stockwork molybdenite deposits tend to be nearly neutral in pH; variable in concentrations of molybdenum (10,000 ug/L); below regulatory guidelines for copper, iron, lead, zinc, and mercury; and locally may exceed guidelines for arsenic, cadmium, and selenium.

  17. Geochemical and mineralogical characterization of a neutral, low-sulfide/high-carbonate tailings impoundment, Markušovce, eastern Slovakia.

    Science.gov (United States)

    Hiller, Edgar; Petrák, Marián; Tóth, Roman; Lalinská-Voleková, Bronislava; Jurkovič, L'ubomír; Kučerová, Gabriela; Radková, Anežka; Sottník, Peter; Vozár, Jaroslav

    2013-11-01

    Tailings deposits generated from mining activities represent a potential risk for the aquatic environment through the release of potentially toxic metals and metalloids occurring in a variety of minerals present in the tailings. Physicochemical and mineralogical characteristics of tailings such as total concentrations of chemical elements, pH, ratio of acid-producing to acid-neutralizing minerals, and primary and secondary mineral phases are very important factors that control the actual release of potentially toxic metals and metalloids from the tailings to the environment. The aims of this study are the determination of geochemical and mineralogical characteristics of tailings deposited in voluminous impoundment situated near the village of Markušovce (eastern Slovakia) and identification of the processes controlling the mobility of selected toxic metals (Cu, Hg) and metalloids (As, Sb). The studied tailings have unique features in comparison with the other tailings investigated previously because of the specific mineral assemblage primarily consisting of barite, siderite, quartz, and minor sulfides. To meet the aims, samples of the tailings were collected from 3 boreholes and 15 excavated pits and subjected to bulk geochemical analyses (i.e., determination of chemical composition, pH, Eh, acid generation, and neutralization potentials) combined with detailed mineralogical characterization using optical microscopy, X-ray diffraction (XRD), electron microprobe analysis (EMPA), and micro-X-ray diffraction (μ-XRD). Additionally, the geochemical and mineralogical factors controlling the transfer of potentially toxic elements from tailings to waters were also determined using short-term batch test (European norm EN 12457), sampling of drainage waters and speciation-equilibrium calculations performed with PHREEQC. The tailings mineral assemblage consists of siderite, barite, quartz, and dolomite. Sulfide minerals constitute only a minor proportion of the tailings

  18. Cameco engineered tailings program: linking applied research with industrial processes for improved tailings performance

    International Nuclear Information System (INIS)

    Kotzer, T.G.

    2010-01-01

    'Full text:' Mine tailings at Cameco's operations are by-products of milling uranium ore having variable concentrations of uranium, metals, oxyanions and trace elements or elements of concern (EOC). Cameco has undertaken an Engineered Tailings (ET) program to optimize tailings performance and minimize environmental EOC impacts, regardless of the milled ore source. Applied geochemical and geotechnical tailings research is key within the ET program. In-situ drilling and experimental programs are used to understand long-term tailings behaviour and help validate source term predictions. Within this, the ET program proactively aids in the development of mill-based processes for production of tailings having improved long-term stability. (author)

  19. Heavy tails of OLS

    DEFF Research Database (Denmark)

    Mikosch, Thomas Valentin; de Vries, Casper

    2013-01-01

    Suppose the tails of the noise distribution in a regression exhibit power law behavior. Then the distribution of the OLS regression estimator inherits this tail behavior. This is relevant for regressions involving financial data. We derive explicit finite sample expressions for the tail probabili...

  20. Influence of hydrology on heavy metal speciation and mobility in a Pb-Zn mine tailing

    International Nuclear Information System (INIS)

    Kovacs, Elza; Dubbin, William E.; Tamas, Janos

    2006-01-01

    Among the inorganic toxicants of greatest concern in mine tailings, Pb, Zn, Cu, Cd and As figure prominently due to their abundance and potential toxicity. Here we report on their biolability and solid-phase speciation in two sediment cores subject to variable hydrological regimes at an abandoned pyritic mine tailing. The oxic conditions of well-drained sediments induced pyrite oxidation and the subsequent liberation of H + , SO 4 2- and considerable quantities of Fe(III), which precipitated as goethite. Solubility of Pb, Zn, Cu and Cd was closely coupled to pH and goethite presence. Metal lability was particularly low in zones of neutralization, formed by the accumulation of calcite, first carried then deposited by percolating waters in both saturated and unsaturated cores. We conclude that differential hydrology induces variable heavy metal speciation and biolability in Pb-Zn mine tailings, and suggest that site-specific risk assessments must account for past and present hydrological regimes. - Variable hydrology influences heavy metal speciation and mobility, and the formation of neutralization zones, in a Pb-Zn mine tailing

  1. An assessment of the long term suitability of present and proposed methods for the management of uranium mill tailings

    International Nuclear Information System (INIS)

    1979-07-01

    Proposals for safe, long-term containment of conventional tailings include 1) storage under water, 2) storage in active, abandoned or specially created underground mines and, 3) storage in open pits, with subsequent flooding or covering with overburden. The underwater proposal can meet most of the requirements of long term containment; however, extensive study of existing tailings deposits in deep water locations will be needed. Underground mines cannot provide sufficient storage capacity, since the tailings bulk during mill operation can occupy twice the volume of the original ore. It is possible to reduce the hazard by reducing the radium and thorium content of the tailings. Proposals for such an undertaking include ore beneficiation with rejection of the relatively innocuous fraction, radium-thorium removal in the mill, and significant changes in both ore processing and treatment of tailings. It is concluded that surface-stored tailings are vulnerable over the long term to dispersion by leaching and water erosion, and that access to a tailings site cannot be prevented, while only a major climatic or seismic event could disturb tailings stored in suitable underwater or underground mine sites. The criteria for determining suitability for each method, however, will need to be identified, tested, and accepted through the normal process of modeling, pilot plant evaluation, monitoring and evaluation. (author)

  2. Tailings neutralization and other alternatives for immobilizing toxic materials in tailings. Final report

    International Nuclear Information System (INIS)

    Opitz, B.E.; Sherwood, D.R.; Dodson, M.E.; Serne, R.J.

    1985-09-01

    This document, ''Tailing Neutralization and Other Alternatives for Immobilizing Toxic Materials in Tailings,'' is the final report in a series of six. It summarizes research completed since the beginning of the project. Three subtasks are included: Subtask A - Neutralization Methods Selection; Subtask B - Laboratory Analysis; and Subtask C - Field Testing. Subtask A reviews treatment processes from other industries to evaluate whether current waste technology from other fields is applicable to the uranium industry. This task also identifies several reagents that were tested for their effectiveness in treating acidic tailings and tailings solution in order to immobilize the contaminants associated with the acid waste. Subtask B describes the laboratory batch and column treatment studies performed on solid waste tailings and tailings solutions over the course of the project. The evaluation of several reagents identified in Subtask A was based on three criteria: (1) treated effluent water quality; (2) neutralized sludge handling and hydraulic properties; and (3) reagent costs and acid neutralizing efficiency. Subtask C presents a field demonstration plan that will evaluate the effectiveness, costs, and benefits of neutralizing acidic uranium mill tailings solution to reduce the potential leaching of toxic trace metals, radionuclides, and macro ions from a tailings impoundment. Details of the related research can be found in the documents listed in the ''Previous Documents in Series.'' 43 refs., 9 figs., 46 tabs

  3. Chemical and mineralogical changes of waste and tailings from the Murgul Cu deposit (Artvin, NE Turkey): implications for occurrence of acid mine drainage.

    Science.gov (United States)

    Sağlam, Emine Selva; Akçay, Miğraç

    2016-04-01

    Being one of the largest copper-producing resources in Turkey, the Murgul deposit has been a source of environmental pollution for very long time. Operated through four open pits with an annual production of about 3 million tons of ore at an average grade of about 0.5% Cu, the deposit to date has produced an enormous pile of waste (exceeding 100 million tons) with tailings composed of 36 % SiO2, 39% Fe2O3 and 32% S, mainly in the form of pyrite and quartz. Waters in the vicinity of the deposit vary from high acid-acid (2.71-3.85) and high-extremely metal rich (34.48-348.12 mg/l in total) in the open pits to near neutral (6.51-7.83) and low metal (14.39-973.52 μg/l in total) in downstream environments. Despite low metal contents and near neutral pH levels of the latter, their suspended particle loads are extremely high and composed mainly of quartz and clay minerals with highly elevated levels of Fe (3.5 to 24.5% Fe2O3; 11% on average) and S (0.5 to 20.6% S; 7% on average), showing that Fe is mainly in the form of pyrite and lesser hematite. They also contain high concentrations of As, Au, Ba, Cu, Pb, and Zn. Waters collected along the course of polluted drainages are supersaturated with respect to Fe phases such as goethite, hematite, maghemite, magnetite, schwertmannite and ferrihydrite. Secondary phases such as Fe-sulphates are only found near the pits, but not along the streams due to neutral pH conditions, where pebbles are covered and cemented by Fe-oxides and hydroxides indicating that oxidation of pyrite has taken place especially at times of low water load. It follows, then, that the pyrite-rich sediment load of streams fed by the waste of the Murgul deposit is currently a big threat to the aquatic life and environment and will continue to be so even after the closure of the deposit. In fact, the oxidation will be enhanced and acidity increased due to natural conditions, which necessitates strong remedial actions to be taken.

  4. Lateral movements of a massive tail influence gecko locomotion: an integrative study comparing tail restriction and autotomy.

    Science.gov (United States)

    Jagnandan, Kevin; Higham, Timothy E

    2017-09-07

    Tails are an intricate component of the locomotor system for many vertebrates. Leopard geckos (Eublepharis macularius) possess a large tail that is laterally undulated during steady locomotion. However, the tail is readily shed via autotomy, resulting in the loss of tail function, loss in body mass, and a cranial shift in the center of mass. To elucidate the function of tail undulations, we investigated changes in limb kinematics after manipulating the tail artificially by restricting tail undulations and naturally by removing the tail via autotomy. Restricting tail undulations resulted in kinematic adjustments similar to those that occur following tail autotomy, characterized by more flexed hind limb joints. These data suggest that effects of autotomy on locomotion may be linked to the loss of tail movements rather than the loss of mass or a shift in center of mass. We also provide empirical support for the link between lateral tail undulations and step length through the rotation of the pelvic girdle and retraction of the femur. Restriction and autotomy of the tail limits pelvic rotation, which reduces femur retraction and decreases step length. Our findings demonstrate a functional role for tail undulations in geckos, which likely applies to other terrestrial vertebrates.

  5. Cobalt—Styles of deposits and the search for primary deposits

    Science.gov (United States)

    Hitzman, Murray W.; Bookstrom, Arthur A.; Slack, John F.; Zientek, Michael L.

    2017-11-30

    the Ducktown (Tennessee) waste and tailings; andKnown five-element vein districts in Arizona and New Mexico, as well as in the Yukon-Tanana terrane of Alaska; and hydrothermal deposits associated with ultramafic rocks along the west coast, in Alaska, and in the Appalachian Mountains.

  6. Injurious tail biting in pigs

    DEFF Research Database (Denmark)

    D'Eath, R.B.; Amott, G.; Turner, S. P.

    2014-01-01

    not allow tail docking at all. Against this background, using a novel approach focusing on research where tail injuries were quantified, we review the measures that can be used to control tail biting in pigs without tail docking. Using this strict criterion, there was good evidence that manipulable...... substrates and feeder space affect damaging tail biting. Only epidemiological evidence was available for effects of temperature and season, and the effect of stocking density was unclear. Studies suggest that group size has little effect, and the effects of nutrition, disease and breed require further...... underlying processes of tail biting. A quantitative comparison of the efficacy of different methods of provision of manipulable materials, and a review of current practices in countries and assurance schemes where tail docking is banned, both suggest that daily provision of small quantities of destructible...

  7. Lateral movements of a massive tail influence gecko locomotion: an integrative study comparing tail restriction and autotomy

    OpenAIRE

    Jagnandan, Kevin; Higham, Timothy E.

    2017-01-01

    Tails are an intricate component of the locomotor system for many vertebrates. Leopard geckos (Eublepharis macularius) possess a large tail that is laterally undulated during steady locomotion. However, the tail is readily shed via autotomy, resulting in the loss of tail function, loss in body mass, and a cranial shift in the center of mass. To elucidate the function of tail undulations, we investigated changes in limb kinematics after manipulating the tail artificially by restricting tail un...

  8. About necessity of remediation and re-cultivation of Taboshar districts' tailings

    International Nuclear Information System (INIS)

    Salomov, J.A.; Mirsaidov, I.U.; Barotov, A.M.

    2012-01-01

    Taboshar uranium deposit is one of the oldest sites of uranium industry and reprocessing in former USSR. During geological survey in 1926 close to Istiklol city (former Taboshar), relatively high radioactivity was revealed on present territory and in 1927 the physical exploration of uranium-containing zones was completed. Active extraction of ore was carried out here from 1945 till 1965 y. Nowadays it is a huge territory with total area of more than 400 hectares covered by surface wastes tailings of hydrometallurgical reprocessing of uranium ores. Disposal complex consists from non-preserved open pit ('Factory of barren ores'), destroyed industrial buildings and four tailings (Tailing I-II, Tailing III, Tailing IV and tailing of industrial workshop 3), containing approximately 55 million tons of wastes, from which approximately 12 million tons are uranium ore's wastes. Total area of four tailing and 'Factory of barren ores' is 63 hectares. Besides, balanced-off ores and overburden rocks i.e. ores and rocks unprofitable for reprocessing should be included here as well. Factor analysis of radiation danger carried out by IAEA expert mission in Istiklol city revealed that radon content in air and aerosol contamination is not a factor of considerable radiation risk for city residents, besides cases of their visit to tailings and living of people directly within zones of their location since territory is well aired out. However, due to bad coverage of tailing, drainage waters draining from zones of their location are highly contaminated by radionuclides and contain high concentrations of manganese, sodium, lead and iron. Drainage waters of former flooded uranium mines and open pits are also considerably contaminated. Such contaminated waters are used all over by local population for cattle watering, watering of garden territories and even for drinking. Thus, the use of drainage and mine waters with high contamination level for drinking and

  9. An assessment of the long term interaction of uranium tailings with the natural environment

    International Nuclear Information System (INIS)

    Lush, D.; Fletcher, R.; Goode, J.; Jurgens, T.

    1978-01-01

    Current investigations of methods for the management of tailings at uranium mill sites raise pertinent questions as to accuracy of our identification of potential hazards and their causes. Of particular relevance are the physical-chemical geomechanisms which may lead to the dispersion of contaminants into the environment and eventually into the food chain. This paper looks at present practices of uranium mill tailings storage in the light of 'Perpetual Care' management concepts and requirements. It examines the potential geomechanisms of transport that would be acting on the tailing over the next millenia. Interesting parallels are drawn between these mechanisms and those geomechanisms which led to the formation of many of the original ore deposits. Central to the substance of this paper is a study currently being undertaken for the Atomic Energy Control Board of Canada. Selected elements to this study will be presented in the paper together with a discussion of relevant peripheral issues

  10. Cost of implementing AECB interim criteria for the closeout of uranium tailings sites

    International Nuclear Information System (INIS)

    1981-04-01

    The main purpose of this study was to arrive at a gross approximation of the costs to the Canadian uranium mining industry of meeting the proposed closeout criteria established by the Atomic Energy Control Board for tailings deposits. Two options have been investigated: on-land disposal and underlake disposal. Given the budget allocated to the study, the estimates must be understood as approximations. Overall cost figures for the Canadian uranium mining industry are linear extensions from a hypothetical base case. The results of a conference held in Ottawa on February 25 and 26 to discuss the proposed AECB interim criteria for the closeout of uranium tailings sites are also included. Representatives from mining firms, provincial regulatory authorities, universities and the Atomic Energy Control board attended the conference

  11. Uranium Mill Tailings Remedial Action Project fiscal year 1997 annual report to stakeholders

    International Nuclear Information System (INIS)

    1997-01-01

    The fiscal year (FY) 1997 annual report is the 19th report on the status of the US Department of Energy's (DOE) Uranium Mill Tailings Remedial Action (UMTRA) Project. In 1978, Congress directed the DOE to assess and clean up contamination at 24 designated former uranium processing sites. The DOE is also responsible for cleaning up properties in the vicinity of the sites where wind and water erosion deposited tailings or people removed them from the site for use in construction or landscaping. Cleanup has been undertaken in cooperation with state governments and Indian tribes within whose boundaries the sites are located. It is being conducted in two phases: the surface project and the groundwater project. This report addresses specifics about the UMTRA surface project

  12. Fiscal year 1996 annual report to stakeholders, Uranium Mill Tailings Remedial Action Project

    International Nuclear Information System (INIS)

    1996-01-01

    This is the Fiscal Year (FY) 1996 annual report on the status of the US Department of Energy's (DOE) Uranium Mill Tailings Remedial Action (UMTRA) Project. In 1978, Congress directed the DOE to assess and clean up contamination at 24 designated former uranium processing sites. The DOE is also responsible for cleaning up properties in the vicinity of the sites where wind and water erosion deposited tailings or people removed them from the site for use in construction of landscaping. Cleanup is being undertaken in cooperation with state governments and Indian tribes within whose boundaries the sites are located. It is being conducted in two phases: the surface project and the ground water project. This report addresses specifics about the surface phase of the UMTRA Project

  13. Significance of Microbial Communities and Interactions in Safeguarding Reactive Mine Tailings by Ecological Engineering▿†

    Science.gov (United States)

    N̆ancucheo, Ivan; Johnson, D. Barrie

    2011-01-01

    Pyritic mine tailings (mineral waste generated by metal mining) pose significant risk to the environment as point sources of acidic, metal-rich effluents (acid mine drainage [AMD]). While the accelerated oxidative dissolution of pyrite and other sulfide minerals in tailings by acidophilic chemolithotrophic prokaryotes has been widely reported, other acidophiles (heterotrophic bacteria that catalyze the dissimilatory reduction of iron and sulfur) can reverse the reactions involved in AMD genesis, and these have been implicated in the “natural attenuation” of mine waters. We have investigated whether by manipulating microbial communities in tailings (inoculating with iron- and sulfur-reducing acidophilic bacteria and phototrophic acidophilic microalgae) it is possible to mitigate the impact of the acid-generating and metal-mobilizing chemolithotrophic prokaryotes that are indigenous to tailing deposits. Sixty tailings mesocosms were set up, using five different microbial inoculation variants, and analyzed at regular intervals for changes in physicochemical and microbiological parameters for up to 1 year. Differences between treatment protocols were most apparent between tailings that had been inoculated with acidophilic algae in addition to aerobic and anaerobic heterotrophic bacteria and those that had been inoculated with only pyrite-oxidizing chemolithotrophs; these differences included higher pH values, lower redox potentials, and smaller concentrations of soluble copper and zinc. The results suggest that empirical ecological engineering of tailing lagoons to promote the growth and activities of iron- and sulfate-reducing bacteria could minimize their risk of AMD production and that the heterotrophic populations could be sustained by facilitating the growth of microalgae to provide continuous inputs of organic carbon. PMID:21965397

  14. Development and application of an iridium tracer for tracking tailings in the central Red Sea

    International Nuclear Information System (INIS)

    Schnier, C.; Fanger, H.U.

    1983-01-01

    In order to investigate the distribution of disposed tailings, the element iridium was applied as a tracer during the prepilot mining test in the Red Sea 1979. In the sediment matrix, Ir can be detected in quantities as small as 25 x 10 -12 g by means of neutron activation analysis. The tracer was obtained by melting down a mixture of 50 kg quartz and 1 kg IrO 2 , then grinding and pulverizing the material to an appropriate grain size distribution. An amount of 480 m 3 tracer-added tailings was disposed in a depth of 400 m close to the Atlantis II deep. Subsequently, in the period 1 month to 2 1/2 years later, 32 sediment samples were taken from the deposition area and analysed for Ir. The Ir concentration observed were surprisingly low and give only vague indications of the spreading of the tailings. (orig.) [de

  15. Metal speciation of historic and new copper mine tailings from Repparfjorden, Northern Norway, before and after acid, base and electrodialytic extraction

    DEFF Research Database (Denmark)

    Pedersen, Kristine B.; Jensen, Pernille Erland; Ottosen, Lisbeth M.

    2017-01-01

    the new mine tailings. Electrodialysis, based on applying an electric field of low intensity to extract metals from polluted soils/sediments, was designed for acidic and alkaline extraction, and in both cases more Cu was extracted than in the pure acid/base extractions, while maintaining low mobilisation......In Kvalsund, Northern Norway, a permit for submarine mine tailings disposal in Repparfjorden was recently issued for a copper mine with expected operation from 2019. A copper mine was active in the same area in the 1970s and also deposited mine tailings in the fjord. Investigations of the metal...... tailings. Substantial desorption (>40%) for both historic and new mine tailings occurred at pH values below 3 and above 12. These results combined with metal speciation, showing that the binding of Cu in the sediment changes around pH values 3 and 10, indicate potential for extraction of more Cu from...

  16. Performance Comparison between Neutralization Tailings and Flotation Tailings Used for Backfill Mix and Mechanism Analysis

    OpenAIRE

    Han, Bin; Sun, Wei; Yu, Shaofeng; Liu, Chao; Yao, Song; Wu, Jianxun

    2016-01-01

    A comparison test of different tailings used for underground backfill was conducted, using neutralized tailings from BIOX and flotation tailings of Jinfeng Mine. Laboratory comparison test results show that, with neutralized tailings, when the cement dosage is at 19%, backfill UCS after 7 days, 14 days, and 28 days are 105%–163%, 80%–102%, and 33%–43%, respectively, which are higher than those of flotation tailings. When the cement dosage is at 12%, backfill UCS after 7 days, 14 days, and 28 ...

  17. Evolution of uranium distribution and speciation in mill tailings, COMINAK Mine, Niger.

    Science.gov (United States)

    Déjeant, Adrien; Galoisy, Laurence; Roy, Régis; Calas, Georges; Boekhout, Flora; Phrommavanh, Vannapha; Descostes, Michael

    2016-03-01

    This study investigated the evolution of uranium distribution and speciation in mill tailings from the COMINAK mine (Niger), in production since 1978. A multi-scale approach was used, which combined high resolution remote sensing imagery, ICP-MS bulk rock analyses, powder X-ray diffraction, Scanning Electron Microscopy, Focused Ion Beam--Transmission Electron Microscopy and X-ray Absorption Near Edge Spectroscopy. Mineralogical analyses showed that some ore minerals, including residual uraninite and coffinite, undergo alteration and dissolution during tailings storage. The migration of uranium and other contaminants depends on (i) the chemical stability of secondary phases and sorbed species (dissolution and desorption processes), and (ii) the mechanical transport of fine particles bearing these elements. Uranium is stabilized after formation of secondary uranyl sulfates and phosphates, and adsorbed complexes on mineral surfaces (e.g. clay minerals). In particular, the stock of insoluble uranyl phosphates increases with time, thus contributing to the long-term stabilization of uranium. At the surface, a sulfate-cemented duricrust is formed after evaporation of pore water. This duricrust limits water infiltration and dust aerial dispersion, though it is enriched in uranium and many other elements, because of pore water rising from underlying levels by capillary action. Satellite images provided a detailed description of the tailings pile over time and allow monitoring of the chronology of successive tailings deposits. Satellite images suggest that uranium anomalies that occur at deep levels in the pile are most likely former surface duricrusts that have been buried under more recent tailings. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Phytoremediation Reduces Dust Emissions from Metal(loid)-Contaminated Mine Tailings.

    Science.gov (United States)

    Gil-Loaiza, Juliana; Field, Jason P; White, Scott A; Csavina, Janae; Felix, Omar; Betterton, Eric A; Sáez, A Eduardo; Maier, Raina M

    2018-04-27

    Environmental and health risk concerns relating to airborne particles from mining operations have focused primarily on smelting activities. However, there are only three active copper smelters and less than a dozen smelters for other metals compared to an estimated 500000 abandoned and unreclaimed hard rock mine tailings in the US that have the potential to generate dust. The problem can also extend to modern tailings impoundments, which may take decades to build and remain barren for the duration before subsequent reclamation. We examined the impact of vegetation cover and irrigation on dust emissions and metal(loid) transport from mine tailings during a phytoremediation field trial at the Iron King Mine and Humboldt Smelter Superfund (IKMHSS) site. Measurements of horizontal dust flux following phytoremediation reveals that vegetated plots with 16% and 32% canopy cover enabled an average dust deposition of 371.7 and 606.1 g m -2 y -1 , respectively, in comparison to the control treatment which emitted dust at an average rate of 2323 g m -2 y -1 . Horizontal dust flux and dust emissions from the vegetated field plots are comparable to emission rates in undisturbed grasslands. Further, phytoremediation was effective at reducing the concentration of fine particulates, including PM 1 , PM 2.5 , and PM 4 , which represent the airborne particulates with the greatest health risks and the greatest potential for long-distance transport. This study demonstrates that phytoremediation can substantially decrease dust emissions as well as the transport of windblown contaminants from mine tailings.

  19. Frost evolution in tailings

    International Nuclear Information System (INIS)

    1991-04-01

    A review was carried out on the physical and thermal mechanisms of permafrost evaluation in soils and uranium tailings. The primary mechanism controlling permafrost evolution is conductive heat transfer with the latent heat of fusion of water being liberated as phase change occurs. Depending on the soil properties and freezing rate, pore water can be expelled from the frost front or pore water can migrate towards the frost front. Solute redistribution may occur as the frost front penetrates into the soil. The rate of frost penetration is a function of the thermal properties of the tailings and the climatic conditions. Computer modelling programmes capable of modelling permafrost evolution were reviewed. The GEOTHERM programme was selected as being the most appropriate for this study. The GEOTHERM programme uses the finite element method of thermal analysis. The ground surface temperature is determined by solving the energy balance equations a the ground surface. The GEOTHERM programme was used to simulate the permafrost evolution in the Key Lake Mine tailings located in north central Saskatchewan. The analyses indicated that the existing frozen zones in the tailing pond will eventually thaw if an average snow depth covers the tailings. Hundreds of years are required to thaw the tailings. If minimal snow cover is present the extent of the frozen zone in the tailings will increase

  20. Fugitive emissions control on dry copper tailing with crushed rock armor

    International Nuclear Information System (INIS)

    Haase, E.F.

    1992-01-01

    Four inactive copper tailing impoundments totalling 1,900 acres near Ajo in southwestern Arizona were covered on horizontal surfaces with a 2 in. nominal thickness of crushed rock to control particulate emissions. The tailings are typically dominated by sand-sized particles but may also include significant PM 10 fractions towards the centers of the impoundments. The technology was selected by Phelps Dodge Corporation, after investigation of several alternatives, as a permanent and practical cover that essentially eliminates fugitive emissions. It simulates the natural desert pavement that characterizes this arid area of the Sonoran Desert. Rocky overburden was crushed to minus 3 in. diameter and broadcast on dry surfaces of tailing impoundments with all-terrain, balloon-tired spreaders. Stony residues in the rock armor tend to cement together following rainfall, forming a crust that enhances surface stability and erosion control. Slopes with windblown tailing deposition were covered to a nominal 6 in. thickness by conventional dozer pushing and blading of minus 10 in. rock over the sides. Athel trees, planted extensively since 1970 on two of the four inactive impoundments, provided partial control of fugitives, but were subjected to harsh environmental conditions, including abrasion from saltating particles. The rock armor functions as a mulch which is expected to improve water relations for existing vegetation and areas seeded with native species. New surface microenvironments, and the virtual elimination of surface creep and saltation, are expected to support native plant growth under favorable climatic conditions

  1. Characterization of oils sands thickened tailings

    Energy Technology Data Exchange (ETDEWEB)

    Scott, J.D.; Jeeravipoolvarn, S.; Donahue, R.; Ozum, B. [Alberta Univ., Edmonton, AB (Canada). Dept. of Civil and Environmental Engineering

    2008-07-01

    This presentation discussed the characterization of oils sands thickened tailings. The problem statement was defined as the fact that many laboratory procedures to characterize fine tailings do not take into account the extraction process, and instead use standardized laboratory tests. The purpose of this presentation was to demonstrate how different extraction processes affect the fine tailings geotechnical properties and water chemistry. Properties that were characterized included particle size analysis from hydrometer-sieve tests; per cent clay from methylene blue tests; per cent clay from mineralogy tests; Atterberg limits; water chemistry; and morphology by scanning electron microscopy. The presentation discussed the origin of fines (silt and clay) in tailings; where fine particles come from; tailings materials; mineralogy of tailings; the hydrometer-sieve test on fine tailings and thickened tailings; and the methylene blue test. It was concluded that the great majority of clay minerals in the tailings come from the clay-shale discontinuous seams and layers. For thickened tailings, the dispersed and non-dispersed hydrometer tests show considerable difference in the amount of clay size material. tabs., figs.

  2. A combined kinetic and diffusion model for pyrite oxidation in tailings - a change in controls with time

    International Nuclear Information System (INIS)

    Elberling, B.; Nicholson, R.V.; Scharer, J.M.

    1994-01-01

    Acidic drainage from the oxidation of mine tailing wastes is an important environmental problem. The purpose of this paper is to develop a model (1) to simulate the rate of oxidation of pyrite over time, (2) to verify the importance of chemical kinetic control and diffusion control on the oxidation rate with time and, (3) to evaluate the sensitivity of the model to critical parameters of the tailings, such as grain size, pyrite content and the effective diffusion coefficient. The source code comprises four main modules including parameter allocation (kinetics, transport), sulphide oxidation (shrinking particle), oxygen transport and pyrite mass balance. The results show that high oxidation rates are observed in the initial time after tailings deposition. During this initial period of high rates, an apparent shift occurs from kinetic to diffusional control over a period of time that depends on the composition and properties of the tailings. Based on the simulation results, it is evident that the overall rate of oxidation after a few years will be controlled dominantly by the diffusion of oxygen rather than by biological or non-biological kinetics in the tailings

  3. Quantitative microbial community analysis of three different sulfidic mine tailing dumps generating acid mine drainage.

    Science.gov (United States)

    Kock, Dagmar; Schippers, Axel

    2008-08-01

    The microbial communities of three different sulfidic and acidic mine waste tailing dumps located in Botswana, Germany, and Sweden were quantitatively analyzed using quantitative real-time PCR (Q-PCR), fluorescence in situ hybridization (FISH), catalyzed reporter deposition-FISH (CARD-FISH), Sybr green II direct counting, and the most probable number (MPN) cultivation technique. Depth profiles of cell numbers showed that the compositions of the microbial communities are greatly different at the three sites and also strongly varied between zones of oxidized and unoxidized tailings. Maximum cell numbers of up to 10(9) cells g(-1) dry weight were determined in the pyrite or pyrrhotite oxidation zones, whereas cell numbers in unoxidized tailings were significantly lower. Bacteria dominated over Archaea and Eukarya at all tailing sites. The acidophilic Fe(II)- and/or sulfur-oxidizing Acidithiobacillus spp. dominated over the acidophilic Fe(II)-oxidizing Leptospirillum spp. among the Bacteria at two sites. The two genera were equally abundant at the third site. The acidophilic Fe(II)- and sulfur-oxidizing Sulfobacillus spp. were generally less abundant. The acidophilic Fe(III)-reducing Acidiphilium spp. could be found at only one site. The neutrophilic Fe(III)-reducing Geobacteraceae as well as the dsrA gene of sulfate reducers were quantifiable at all three sites. FISH analysis provided reliable data only for tailing zones with high microbial activity, whereas CARD-FISH, Q-PCR, Sybr green II staining, and MPN were suitable methods for a quantitative microbial community analysis of tailings in general.

  4. Contaminant transport, revegetation, and trace element studies at inactive uranium mill tailings piles

    International Nuclear Information System (INIS)

    Dreesen, D.R.; Marple, M.L.; Kelley, N.E.

    1978-01-01

    The stabilization of inactive uranium mill tailings piles is presently under study. These studies have included investigations of stabilizing tailings by attempting to establish native vegetation without applying irrigation. Examination of processes which transport tailings or associated contaminants into the environment has been undertaken to better understand the containment provided by various stabilization methods. The uptake of toxic trace elements and radionuclides by vegetation has been examined as a mechanism of contaminant transport. The source terms of 222 Rn from inactive piles have been determined as well as the attenuation of radon flux provided by shallow soil covers. The possibility of shallow ground water contamination around an inactive pile has been examined to determine the significance of ground water transport as a mode of contaminant migration. The rationale in support of trace element studies related to uranium milling activities is presented including the enrichment, migration, and toxicities of trace elements often associated with uranium deposits. Some concepts for the stabilization of inactive piles are presented to extrapolate from research findings to practical applications. 25 references, 8 tables

  5. Evolution of uranium distribution and speciation in mill tailings, COMINAK Mine, Niger

    International Nuclear Information System (INIS)

    Déjeant, Adrien; Galoisy, Laurence; Roy, Régis; Calas, Georges; Boekhout, Flora; Phrommavanh, Vannapha; Descostes, Michael

    2016-01-01

    This study investigated the evolution of uranium distribution and speciation in mill tailings from the COMINAK mine (Niger), in production since 1978. A multi-scale approach was used, which combined high resolution remote sensing imagery, ICP-MS bulk rock analyses, powder X-ray diffraction, Scanning Electron Microscopy, Focused Ion Beam — Transmission Electron Microscopy and X-ray Absorption Near Edge Spectroscopy. Mineralogical analyses showed that some ore minerals, including residual uraninite and coffinite, undergo alteration and dissolution during tailings storage. The migration of uranium and other contaminants depends on (i) the chemical stability of secondary phases and sorbed species (dissolution and desorption processes), and (ii) the mechanical transport of fine particles bearing these elements. Uranium is stabilized after formation of secondary uranyl sulfates and phosphates, and adsorbed complexes on mineral surfaces (e.g. clay minerals). In particular, the stock of insoluble uranyl phosphates increases with time, thus contributing to the long-term stabilization of uranium. At the surface, a sulfate-cemented duricrust is formed after evaporation of pore water. This duricrust limits water infiltration and dust aerial dispersion, though it is enriched in uranium and many other elements, because of pore water rising from underlying levels by capillary action. Satellite images provided a detailed description of the tailings pile over time and allow monitoring of the chronology of successive tailings deposits. Satellite images suggest that uranium anomalies that occur at deep levels in the pile are most likely former surface duricrusts that have been buried under more recent tailings. - Highlights: • The evolution of U distribution and speciation in mill tailings is investigated. • High resolution satellite images provide useful information on tailings evolution. • U and many other elements are enriched in a sulfate-rich duricrust. • Formation of

  6. Evolution of uranium distribution and speciation in mill tailings, COMINAK Mine, Niger

    Energy Technology Data Exchange (ETDEWEB)

    Déjeant, Adrien, E-mail: adrien.dejeant@normalesup.org [Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Case 115, 4 place Jussieu, 75005 Paris (France); Université Paris Diderot — Paris VII, 5 rue Thomas Mann, 75013 Paris (France); Galoisy, Laurence [Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Case 115, 4 place Jussieu, 75005 Paris (France); Université Pierre et Marie Curie — Paris VI, 4 place Jussieu, 75005 Paris (France); Roy, Régis [AREVA Mines — Geoscience Department, Tour AREVA, 1 place Jean Millier, 92084 Paris, La Défense (France); Calas, Georges; Boekhout, Flora [Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Case 115, 4 place Jussieu, 75005 Paris (France); Université Pierre et Marie Curie — Paris VI, 4 place Jussieu, 75005 Paris (France); Phrommavanh, Vannapha; Descostes, Michael [AREVA Mines — R& D Department, BAL 0414C-2, Tour AREVA, 1 place Jean Millier, 92084 Paris, La Défense (France)

    2016-03-01

    This study investigated the evolution of uranium distribution and speciation in mill tailings from the COMINAK mine (Niger), in production since 1978. A multi-scale approach was used, which combined high resolution remote sensing imagery, ICP-MS bulk rock analyses, powder X-ray diffraction, Scanning Electron Microscopy, Focused Ion Beam — Transmission Electron Microscopy and X-ray Absorption Near Edge Spectroscopy. Mineralogical analyses showed that some ore minerals, including residual uraninite and coffinite, undergo alteration and dissolution during tailings storage. The migration of uranium and other contaminants depends on (i) the chemical stability of secondary phases and sorbed species (dissolution and desorption processes), and (ii) the mechanical transport of fine particles bearing these elements. Uranium is stabilized after formation of secondary uranyl sulfates and phosphates, and adsorbed complexes on mineral surfaces (e.g. clay minerals). In particular, the stock of insoluble uranyl phosphates increases with time, thus contributing to the long-term stabilization of uranium. At the surface, a sulfate-cemented duricrust is formed after evaporation of pore water. This duricrust limits water infiltration and dust aerial dispersion, though it is enriched in uranium and many other elements, because of pore water rising from underlying levels by capillary action. Satellite images provided a detailed description of the tailings pile over time and allow monitoring of the chronology of successive tailings deposits. Satellite images suggest that uranium anomalies that occur at deep levels in the pile are most likely former surface duricrusts that have been buried under more recent tailings. - Highlights: • The evolution of U distribution and speciation in mill tailings is investigated. • High resolution satellite images provide useful information on tailings evolution. • U and many other elements are enriched in a sulfate-rich duricrust. • Formation of

  7. Uranium mill tailings management

    International Nuclear Information System (INIS)

    1982-01-01

    Facilities for the disposal of uranium mill tailings will invariably be subjected to geomorphological and climatological influences in the long-term. Proceedings of a workshop discuss how the principles of geomorphology can be applied to the siting, design, construction, decommissioning and rehabilitation of disposal facilities in order to provide for long-term containment and stability of tailings. The characteristics of tailings and their behaviour after disposal influence the potential impacts which might occur in the long-term. Proceedings of another workshop examine the technologies for uranium ore processing and tailings conditioning with a view to identifying improvements that could be made in such characteristics

  8. Remote sensing supported surveillance and characterization of tailings behavior at a gold mine site, Finland.

    Science.gov (United States)

    Rauhala, Anssi; Tuomela, Anne; Rossi, Pekka M.; Davids, Corine

    2017-04-01

    The management of vast amounts of tailings produced is one of the key issues in mining operations. The effective and economic disposal of the waste requires knowledge concerning both basic physical properties of the tailings as well as more complex aspects such as consolidation behavior. The behavior of tailings in itself is a very complex issue that can be affected by flocculation, sedimentation, consolidation, segregation, deposition, freeze-thaw, and desiccation phenomena. The utilization of remote sensing in an impoundment-scale monitoring of tailings could benefit the management of tailings, and improve our knowledge on tailings behavior. In order to gain better knowledge of tailings behavior in cold climate, we have utilized both modern remote sensing techniques and more traditional in situ and laboratory measurements in characterizing thickened gold tailings behavior at a Finnish gold mine site, where the production has been halted due to low gold prices. The remote sensing measurements consisted of elevation datasets collected from unmanned aerial vehicles during summers 2015 and 2016, and a further campaign is planned for the summer 2017. The ongoing traditional measurements include for example particle-size distribution, frost heave, frost depth, water retention, temperature profile, and rheological measurements. Initial results from the remote sensing indicated larger than expected settlements on parts of the tailings impoundment, and also highlighted some of the complexities related to data processing. The interpretation of the results and characterization of the behavior is in this case complicated by possible freeze-thaw effects and potential settlement of the impoundment bottom structure consisting of natural peat. Experiments with remote sensing and unmanned aerial vehicles indicate that they could offer potential benefits in frequent mine site monitoring, but there is a need towards more robust and streamlined data acquisition and processing. The

  9. Acid production potentials of massive sulfide minerals and lead-zinc mine tailings: a medium-term study.

    Science.gov (United States)

    Çelebi, Emin Ender; Öncel, Mehmet Salim; Kobya, Mehmet

    2018-01-01

    Weathering of sulfide minerals is a principal source of acid generation. To determine acid-forming potentials of sulfide-bearing materials, two basic approaches named static and kinetic tests are available. Static tests are short-term, and easily undertaken within a few days and in a laboratory. In contrast, kinetic tests are long-term procedures and mostly carried out on site. In this study, experiments were conducted over a medium-term period of 2 months, not as short as static tests and also not as long as kinetic tests. As a result, pH and electrical conductivity oscillations as a function of time, acid-forming potentials and elemental contents of synthetically prepared rainwater leachates of massive sulfides and sulfide-bearing lead-zinc tailings from abandoned and currently used deposition areas have been determined. Although the lowest final pH of 2.70 was obtained in massive pyrite leachate, massive chalcopyrite leachate showed the highest titrable acidity of 1.764 g H 2 SO 4 /L. On the other hand, a composite of currently deposited mine tailings showed no acidic characteristic with a final pH of 7.77. The composite abandoned mine tailing leachate had a final pH of 6.70, close to the final pH of massive galena and sphalerite leachates, and produced a slight titrable acidity of 0.130 g H 2 SO 4 /L.

  10. Mine tailings disposal

    International Nuclear Information System (INIS)

    Gonzales, P.A.; Adams, B.J.

    1980-06-01

    The hydrologic evaluation of mine tailings disposal sites after they are abandoned is considered in relation to their potential environmental impact on a long term basis. There is a direct relation between the amounts and types of water leaving a disposal site and the severity of the potential damage to the environment. The evaluation of the relative distribution of the precipitation reaching the ground into evaporation, runoff and infiltration is obtained for a selected site and type of tailings material whose characteristics and physical properties were determined in the soils laboratory. A conceptual model of the hydrologic processes involved and the corresponding mathematical model were developed to simulate the physical system. A computer program was written to solve the set of equations forming the mathematical model, considering the physical properties of the tailings and the rainfall data selected. The results indicate that the relative distribution of the precipitation depends on the surface and upper layer of the tailings and that the position of the groundwater table is governed by the flow through the bottom of the profile considered. The slope of the surface of the mass of tailings was found to be one of the principal factors affecting the relative distribution of precipitation and, therefore, the potential pollution of the environment

  11. Solvent extraction of Cu, Mo, V, and U from leach solutions of copper ore and flotation tailings

    International Nuclear Information System (INIS)

    Smolinski, Tomasz; Wawszczak, Danuta; Deptula, Andrzej; Lada, Wieslawa; Olczak, Tadeusz; Rogowski, Marcin; Pyszynska, Marta; Chmielewski, Andrzej Grzegorz

    2017-01-01

    Flotation tailings from copper production are deposits of copper and other valuable metals, such as Mo, V and U. New hydrometallurgical technologies are more economical and open up new possibilities for metal recovery. This work presents results of the study on the extraction of copper by mixed extractant consisting p-toluidine dissolved in toluene. The possibility of simultaneous liquid-liquid extraction of molybdenum and vanadium was examined. D2EHPA solutions was used as extractant, and recovery of individual elements compared for the representative samples of ore and copper flotation tailings. Radiometric methods were applied for process optimization. (author)

  12. Solvent extraction of Cu, Mo, V, and U from leach solutions of copper ore and flotation tailings.

    Science.gov (United States)

    Smolinski, Tomasz; Wawszczak, Danuta; Deptula, Andrzej; Lada, Wieslawa; Olczak, Tadeusz; Rogowski, Marcin; Pyszynska, Marta; Chmielewski, Andrzej Grzegorz

    2017-01-01

    Flotation tailings from copper production are deposits of copper and other valuable metals, such as Mo, V and U. New hydrometallurgical technologies are more economical and open up new possibilities for metal recovery. This work presents results of the study on the extraction of copper by mixed extractant consisting p -toluidine dissolved in toluene. The possibility of simultaneous liquid-liquid extraction of molybdenum and vanadium was examined. D2EHPA solutions was used as extractant, and recovery of individual elements compared for the representative samples of ore and copper flotation tailings. Radiometric methods were applied for process optimization.

  13. TIDAL TAILS OF MINOR MERGERS. II. COMPARING STAR FORMATION IN THE TIDAL TAILS OF NGC 2782

    Energy Technology Data Exchange (ETDEWEB)

    Knierman, Karen A.; Scowen, Paul; Veach, Todd; Groppi, Christopher [School of Earth and Space Exploration, Arizona State University, 550 E. Tyler Mall, Room PSF-686 (P.O. Box 871404), Tempe, AZ 85287-1404 (United States); Mullan, Brendan; Charlton, Jane [Department of Astronomy and Astrophysics, Penn State University, 525 Davey Lab, University Park, PA (United States); Konstantopoulos, Iraklis [Australian Astronomical Observatory, P.O. Box 915, North Ryde NSW 1670 (Australia); Knezek, Patricia M., E-mail: karen.knierman@asu.edu, E-mail: paul.scowen@asu.edu, E-mail: tveach@asu.edu, E-mail: cgroppi@asu.edu, E-mail: mullan@astro.psu.edu, E-mail: iraklis@aao.gov.au, E-mail: pknezek@noao.edu [WIYN Consortium, Inc., 950 N. Cherry Avenue, Tucson, AZ 85719 (United States)

    2013-09-10

    The peculiar spiral NGC 2782 is the result of a minor merger with a mass ratio {approx}4: 1 occurring {approx}200 Myr ago. This merger produced a molecular and H I-rich, optically bright eastern tail and an H I-rich, optically faint western tail. Non-detection of CO in the western tail by Braine et al. suggested that star formation had not yet begun. However, deep UBVR and H{alpha} narrowband images show evidence of recent star formation in the western tail, though it lacks massive star clusters and cluster complexes. Using Herschel PACS spectroscopy, we discover 158 {mu}m [C II] emission at the location of the three most luminous H{alpha} sources in the eastern tail, but not at the location of the even brighter H{alpha} source in the western tail. The western tail is found to have a normal star formation efficiency (SFE), but the eastern tail has a low SFE. The lack of CO and [C II] emission suggests that the western tail H II region may have a low carbon abundance and be undergoing its first star formation. The western tail is more efficient at forming stars, but lacks massive clusters. We propose that the low SFE in the eastern tail may be due to its formation as a splash region where gas heating is important even though it has sufficient molecular and neutral gas to make massive star clusters. The western tail, which has lower gas surface density and does not form high-mass star clusters, is a tidally formed region where gravitational compression likely enhances star formation.

  14. TIDAL TAILS OF MINOR MERGERS. II. COMPARING STAR FORMATION IN THE TIDAL TAILS OF NGC 2782

    International Nuclear Information System (INIS)

    Knierman, Karen A.; Scowen, Paul; Veach, Todd; Groppi, Christopher; Mullan, Brendan; Charlton, Jane; Konstantopoulos, Iraklis; Knezek, Patricia M.

    2013-01-01

    The peculiar spiral NGC 2782 is the result of a minor merger with a mass ratio ∼4: 1 occurring ∼200 Myr ago. This merger produced a molecular and H I-rich, optically bright eastern tail and an H I-rich, optically faint western tail. Non-detection of CO in the western tail by Braine et al. suggested that star formation had not yet begun. However, deep UBVR and Hα narrowband images show evidence of recent star formation in the western tail, though it lacks massive star clusters and cluster complexes. Using Herschel PACS spectroscopy, we discover 158 μm [C II] emission at the location of the three most luminous Hα sources in the eastern tail, but not at the location of the even brighter Hα source in the western tail. The western tail is found to have a normal star formation efficiency (SFE), but the eastern tail has a low SFE. The lack of CO and [C II] emission suggests that the western tail H II region may have a low carbon abundance and be undergoing its first star formation. The western tail is more efficient at forming stars, but lacks massive clusters. We propose that the low SFE in the eastern tail may be due to its formation as a splash region where gas heating is important even though it has sufficient molecular and neutral gas to make massive star clusters. The western tail, which has lower gas surface density and does not form high-mass star clusters, is a tidally formed region where gravitational compression likely enhances star formation

  15. THE NARROW X-RAY TAIL AND DOUBLE Hα TAILS OF ESO 137-002 IN A3627

    International Nuclear Information System (INIS)

    Zhang, B.; Lin, X. B.; Kong, X.; Sun, M.; Ji, L.; Sarazin, C.; Nulsen, P. E. J.; Forman, W.; Jones, C.; Roediger, E.; Donahue, M.; Voit, G. M.

    2013-01-01

    We present the analysis of a deep Chandra observation of a ∼2 L * late-type galaxy, ESO 137-002, in the closest rich cluster A3627. The Chandra data reveal a long (∼>40 kpc) and narrow tail with a nearly constant width (∼3 kpc) to the southeast of the galaxy, and a leading edge ∼1.5 kpc from the galaxy center on the upstream side of the tail. The tail is most likely caused by the nearly edge-on stripping of ESO 137-002's interstellar medium (ISM) by ram pressure, compared to the nearly face-on stripping of ESO 137-001 discussed in our previous work. Spectral analysis of individual regions along the tail shows that the gas throughout it has a rather constant temperature, ∼1 keV, very close to the temperature of the tails of ESO 137-001, if the same atomic database is used. The derived gas abundance is low (∼0.2 solar with the single-kT model), an indication of the multiphase nature of the gas in the tail. The mass of the X-ray tail is only a small fraction (<5%) of the initial ISM mass of the galaxy, suggesting that the stripping is most likely at an early stage. However, with any of the single-kT, double-kT, and multi-kT models we tried, the tail is always 'over-pressured' relative to the surrounding intracluster medium (ICM), which could be due to the uncertainties in the abundance, thermal versus non-thermal X-ray emission, or magnetic support in the ICM. The Hα data from the Southern Observatory for Astrophysical Research show a ∼21 kpc tail spatially coincident with the X-ray tail, as well as a secondary tail (∼12 kpc long) to the east of the main tail diverging at an angle of ∼23° and starting at a distance of ∼7.5 kpc from the nucleus. At the position of the secondary Hα tail, the X-ray emission is also enhanced at the ∼2σ level. We compare the tails of ESO 137-001 and ESO 137-002, and also compare the tails to simulations. Both the similarities and differences of the tails pose challenges to the simulations. Several implications are

  16. Tailings and mineral carbonation : the potential for atmospheric CO{sub 2} sequestration

    Energy Technology Data Exchange (ETDEWEB)

    Rollo, H.A. [Lorax Environmental Services Ltd., Vancouver, BC (Canada); Jamieson, H.E. [Queen' s Univ., Kingston, ON (Canada). Dept. of Geological Sciences and Geological Engineering; Lee, C.A. [Dillon Consulting Ltd., Cambridge, ON (Canada)

    2009-02-15

    Carbon dioxide (CO{sub 2}) sequestration includes geological storage, ocean storage, organic storage, and mineral storage (mineral carbonation). This presentation discussed tailings and mineral carbonation and the potential for atmospheric CO{sub 2} sequestration. In particular, it outlined CO{sub 2} sequestration and presented a history of investigations. The Ekati Diamond Mine was discussed with particular reference to its location, geology, and processing. Other topics that were presented included mineralogy; water chemistry; modeling results; and estimates of annual CO{sub 2} sequestration. Conclusions and implications were also presented. It was concluded that ore processing at mines with ultramafic host rocks have the potential to partially offset CO{sub 2} emissions. In addition, it was found that existing tailings at ultramafic deposits may be viable source materials for CO{sub 2} sequestration by mineral carbonation. tabs., figs.

  17. A coupled modelling effort to study the fate of contaminated sediments downstream of the Coles Hill deposit, Virginia, USA

    Directory of Open Access Journals (Sweden)

    C. F. Castro-Bolinaga

    2015-03-01

    Full Text Available This paper presents the preliminary results of a coupled modelling effort to study the fate of tailings (radioactive waste-by product downstream of the Coles Hill uranium deposit located in Virginia, USA. The implementation of the overall modelling process includes a one-dimensional hydraulic model to qualitatively characterize the sediment transport process under severe flooding conditions downstream of the potential mining site, a two-dimensional ANSYS Fluent model to simulate the release of tailings from a containment cell located partially above the local ground surface into the nearby streams, and a one-dimensional finite-volume sediment transport model to examine the propagation of a tailings sediment pulse in the river network located downstream. The findings of this investigation aim to assist in estimating the potential impacts that tailings would have if they were transported into rivers and reservoirs located downstream of the Coles Hill deposit that serve as municipal drinking water supplies.

  18. Attitudes of Dutch Pig Farmers Towards Tail Biting and Tail Docking

    NARCIS (Netherlands)

    Bracke, M.B.M.; Lauwere, de C.C.; Wind, S.M.M.; Zonderland, J.J.

    2013-01-01

    The Dutch policy objective of a fully sustainable livestock sector without mutilations by 2023 is not compatible with the routine practice of tail docking to minimize the risk of tail biting. To examine farmer attitudes towards docking, a telephone survey was conducted among 487 conventional and 33

  19. Tail-weighted dependence measures with limit being the tail dependence coefficient

    KAUST Repository

    Lee, David

    2017-12-02

    For bivariate continuous data, measures of monotonic dependence are based on the rank transformations of the two variables. For bivariate extreme value copulas, there is a family of estimators (Formula presented.), for (Formula presented.), of the extremal coefficient, based on a transform of the absolute difference of the α power of the ranks. In the case of general bivariate copulas, we obtain the probability limit (Formula presented.) of (Formula presented.) as the sample size goes to infinity and show that (i) (Formula presented.) for (Formula presented.) is a measure of central dependence with properties similar to Kendall\\'s tau and Spearman\\'s rank correlation, (ii) (Formula presented.) is a tail-weighted dependence measure for large α, and (iii) the limit as (Formula presented.) is the upper tail dependence coefficient. We obtain asymptotic properties for the rank-based measure (Formula presented.) and estimate tail dependence coefficients through extrapolation on (Formula presented.). A data example illustrates the use of the new dependence measures for tail inference.

  20. Tail-weighted dependence measures with limit being the tail dependence coefficient

    KAUST Repository

    Lee, David; Joe, Harry; Krupskii, Pavel

    2017-01-01

    For bivariate continuous data, measures of monotonic dependence are based on the rank transformations of the two variables. For bivariate extreme value copulas, there is a family of estimators (Formula presented.), for (Formula presented.), of the extremal coefficient, based on a transform of the absolute difference of the α power of the ranks. In the case of general bivariate copulas, we obtain the probability limit (Formula presented.) of (Formula presented.) as the sample size goes to infinity and show that (i) (Formula presented.) for (Formula presented.) is a measure of central dependence with properties similar to Kendall's tau and Spearman's rank correlation, (ii) (Formula presented.) is a tail-weighted dependence measure for large α, and (iii) the limit as (Formula presented.) is the upper tail dependence coefficient. We obtain asymptotic properties for the rank-based measure (Formula presented.) and estimate tail dependence coefficients through extrapolation on (Formula presented.). A data example illustrates the use of the new dependence measures for tail inference.

  1. Copper tailings in stucco mortars

    Directory of Open Access Journals (Sweden)

    Osvaldo Pavez

    Full Text Available Abstract This investigation addressed the evaluation of the use of copper tailings in the construction industry in order to reduce the impact on the environment. The evaluation was performed by a technical comparison between stucco mortars prepared with crushed conventional sand and with copper tailings sand. The best results were achieved with the stucco mortars containing tailings. The tailings presented a fine particles size distribution curve different from that suggested by the standard. The values of compressive strength, retentivity, and adherence in the stucco mortars prepared with copper tailings were much higher than those obtained with crushed sand. According to the results from this study, it can be concluded that the preparation of stucco mortars using copper tailings replacing conventional sand is a technically feasible alternative for the construction industry, presenting the benefit of mitigating the impact of disposal to the environment.

  2. Research on Long Tail Recommendation Algorithm

    Science.gov (United States)

    Hu, Xuezhi; Zhang, Chuang; Wu, Ming; Zeng, Yang

    2017-10-01

    Most recommendation systems in the major electronic commerce platforms are influenced by the long tail effect more or less. There are sufficient researches of how to assess recommendation effect while no criteria to evaluate long tail recommendation rate. In this study, we first discussed the existing problems of recommending long tail products through specific experiments. Then we proposed a long tail evaluation criteria and compared the performance in long tail recommendation between different models.

  3. Tail Asymptotics for the Sum of two Heavy-tailed Dependent Risks

    DEFF Research Database (Denmark)

    Albrecher, H.; Asmussen, Søren

    Let X1,X2 denote positive exchangable heavy-tailed random variables with continuous marginal distribution function F. The asymptotic behavior of the tail of X1 + X2 is studied in a general copula framework and some bounds and extremal properties are provided. For more specific assumptions on F...

  4. Runaway tails in magnetized plasmas

    Science.gov (United States)

    Moghaddam-Taaheri, E.; Vlahos, L.; Rowland, H. L.; Papadopoulos, K.

    1985-01-01

    The evolution of a runaway tail driven by a dc electric field in a magnetized plasma is analyzed. Depending on the strength of the electric field and the ratio of plasma to gyrofrequency, there are three different regimes in the evolution of the tail. The tail can be (1) stable with electrons accelerated to large parallel velocities, (2) unstable to Cerenkov resonance because of the depletion of the bulk and the formation of a positive slope, (3) unstable to the anomalous Doppler resonance instability driven by the large velocity anisotropy in the tail. Once an instability is triggered (Cerenkov or anomalous Doppler resonance) the tail relaxes into an isotropic distribution. The role of a convection type loss term is also discussed.

  5. Marble wastes and pig slurry improve the environmental and plant-relevant properties of mine tailings.

    Science.gov (United States)

    Kabas, S; Faz, A; Acosta, J A; Arocena, J M; Zornoza, R; Martínez-Martínez, S; Carmona, D M

    2014-02-01

    Poor soil fertility is often the biggest challenge to the establishment of vegetation in mine wastes deposits. We conducted field trials in the El Gorguel and El Lirio sites in SE Spain, two representative tailing ponds of similar properties except for pH, to understand the environmental and plant-relevant benefits of marble waste (MW) and pig slurry (PS) applications to mine tailings. Low pH (5.4) tailings (El Lirio) exhibit reduction of up to fourfold in bio-availability of metals as shown by the DTPA-Zn, Pb, water-soluble Zn, Pb and up to 3× for water-soluble Cd. Tailings in El Gorguel have high pH (7.4) and did not exhibit significant trends in the reductions of water-extractable Zn, Pb, Cd and Cu. Improvements to the edaphic (plant-relevant) properties of tailings after the amendments are not as sensitive to pH compared to the environmental characteristics. The two sites had increases in aggregate stability, organic matter (total N and organic C) although total N is higher in the El Gorguel (up to 212 μg N kg(-1)) than the El Lirio (up to 26 μg N kg(-1)). However, cation exchange capacities are similar in both sites at 15.2 cmol(+) kg(-1). We conclude that the characteristics, especially pH, of tailing materials significantly influence the fate of metals but not improvements to plant-relevant properties such as cation exchange capacity and aggregate stability 1 year after the application of MW and PS amendments.

  6. Analysis of sub-bandgap losses in TiO2 coating deposited via single and dual ion beam deposition

    Czech Academy of Sciences Publication Activity Database

    Žídek, Karel; Hlubuček, Jiří; Horodyská, Petra; Budasz, Jiří; Václavík, Jan

    2017-01-01

    Roč. 626, March (2017), s. 60-65 ISSN 0040-6090 R&D Projects: GA MŠk(CZ) LO1206 Institutional support: RVO:61389021 Keywords : Ion beam deposition * Titanium dioxide * Optical coating * Sub-bandgap losses * Urbach tail Subject RIV: BH - Optics, Masers, Lasers OBOR OECD: Optics (including laser optics and quantum optics) Impact factor: 1.879, year: 2016 http://www.sciencedirect.com/science/article/pii/S0040609017301256

  7. 226Ra concentrations in crayfish tissues, water, and sediments from the Serpent River Basin in Northeastern Ontario, Canada

    International Nuclear Information System (INIS)

    Alikhan, M.A.

    1996-01-01

    Lower Serpent River, as well as Elliot, McCarthy and McCabe lakes had highest 226 Ra contamination, Chrisman, Quirke and Whiskey lakes a moderate one, Flack and Semiwhite lakes and the 'distant' control, Lake Wanapitei, the lowest. 226 Ra activity in Cambarus robustus tissues was directly related to their background levels. Thus, concentration coefficient (tissue/sediment concentrations) for 226 Ra ranged from 0.53 to 0.74 in highly contaminated Elliot and McCarthy lakes, 0.28 to 0.59 in moderately contaminated Quirke and Whiskey lakes, and from 0.27 to 3.44 in least contaminated Semiwhite and Flack lakes. Among various organs analysed, exoskeleton showed the highest (43.04 - 90.69%) and the tail muscles the lowest (2.95 -17.14%) 226 Ra activity. 226 Ra concentrations in the alimentary canal were considered a part of the ambient environment as they had not been absorbed

  8. On possibilities of using global monitoring in effective prevention of tailings storage facilities failures.

    Science.gov (United States)

    Stefaniak, Katarzyna; Wróżyńska, Magdalena

    2018-02-01

    Protection of common natural goods is one of the greatest challenges man faces every day. Extracting and processing natural resources such as mineral deposits contributes to the transformation of the natural environment. The number of activities designed to keep balance are undertaken in accordance with the concept of integrated order. One of them is the use of comprehensive systems of tailings storage facility monitoring. Despite the monitoring, system failures still occur. The quantitative aspect of the failures illustrates both the scale of the problem and the quantitative aspect of the consequences of tailings storage facility failures. The paper presents vast possibilities provided by the global monitoring in the effective prevention of these failures. Particular attention is drawn to the potential of using multidirectional monitoring, including technical and environmental monitoring by the example of one of the world's biggest hydrotechnical constructions-Żelazny Most Tailings Storage Facility (TSF), Poland. Analysis of monitoring data allows to take preventive action against construction failures of facility dams, which can have devastating effects on human life and the natural environment.

  9. TIDAL TAILS OF MINOR MERGERS: STAR FORMATION EFFICIENCY IN THE WESTERN TAIL OF NGC 2782

    Energy Technology Data Exchange (ETDEWEB)

    Knierman, Karen; Scowen, Paul; Jansen, Rolf A. [School of Earth and Space Exploration, Arizona State University, 550 East Tyler Mall, Room PSF-686 (P.O. Box 871404), Tempe, AZ 85287-1404 (United States); Knezek, Patricia M. [WIYN Consortium, Inc., 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Wehner, Elizabeth, E-mail: karen.knierman@asu.edu, E-mail: paul.scowen@asu.edu, E-mail: rolf.jansen@asu.edu, E-mail: pknezek@noao.edu, E-mail: ewehner@haverford.edu [Department of Astronomy, Haverford College, Haverford, PA 19041 (United States)

    2012-04-10

    While major mergers and their tidal debris are well studied, they are less common than minor mergers (mass ratios {approx}< 0.3). The peculiar spiral NGC 2782 is the result of a merger between two disk galaxies with a mass ratio of {approx}4: 1 occurring {approx}200 Myr ago. This merger produced a molecular and H I-rich, optically bright eastern tail and an H I-rich, optically faint western tail. Non-detection of CO in the western tail by Braine et al. suggested that star formation had not yet begun to occur in that tidal tail. However, deep H{alpha} narrowband images show evidence of recent star formation in the western tail. Across the entire western tail, we find the global star formation rate per unit area ({Sigma}{sub SFR}) to be several orders of magnitude less than expected from the total gas density. Together with extended FUV+NUV emission from Galaxy Evolution Explorer along the tail, this indicates a low global star formation efficiency in the tidal tail producing lower mass star clusters. The H II region that we observed has a local (few-kiloparsec scale) {Sigma}{sub SFR} from H{alpha} that is less than that expected from the total gas density, which is consistent with other observations of tidal debris. The star formation efficiency of this H II region inferred from the total gas density is low, but normal when inferred from the molecular gas density. These results suggest the presence of a very small, locally dense region in the western tail of NGC 2782 or of a low-metallicity and/or low-pressure star-forming region.

  10. Thermal stabilization of uranium mill tailings

    International Nuclear Information System (INIS)

    Dreesen, D.R.; Williams, J.M.; Cokal, E.J.

    1981-01-01

    The sintering of tailings at high temperatures (1200 0 C) has shown promise as a conditioning approach that greatly reduces the 222 Rn emanation of uranium mill tailings. The structure of thermally stabilized tailings has been appreciably altered producing a material that will have minimal management requirements and will be applicable to on-site processing and disposal. The mineralogy of untreated tailings is presented to define the structure of the original materials. Quartz predominates in most tailings samples; however, appreciable quantities of gypsum, clay, illite, or albites are found in some tailings. Samples from the Durango and Shiprock sites have plagioclase-type aluminosilicates and non-aluminum silicates as major components. The iron-rich vanadium tailings from the Salt Lake City site contain appreciable quantities of α-hematite and chloroapatite. The reduction in radon emanation power and changes in mineralogy as a function of sintering temperature are presented

  11. Which is the most preventive measure against tail damage in finisher pigs: tail docking, straw provision or lowered stocking density?

    DEFF Research Database (Denmark)

    Larsen, Mona Lilian Vestbjerg; Andersen, Heidi Mai-Lis; Pedersen, Lene Juul

    2018-01-01

    One challenge of intensive pig production is tail damage caused by tail biting, and farmers often decrease the prevalence of tail damage through tail docking. However, tail docking is not an optimal preventive measure against tail damage and thus, it would be preferable to replace it. The aim of ...

  12. Natural radionuclides in bauxitic tailings (Red-Mud) in the Gulf of Corinth, Greece

    International Nuclear Information System (INIS)

    Papatheodorou, G.; Maratou, A.; Ferentinos, G.; Papaefthymiou, H.

    2004-01-01

    A detailed environmental survey was carried out in the central Gulf of Corinth in order to determine radionuclides in the bauxite ed-mud tailings which have been discharged on the sea floor by a Bauxite Processing Plant (Aluminio Ellados A.E). The discharge of bauxitic tailings via two pipelines at a water depth of 100 m, in Antikyra Bay (Northern Gulf of Corinth), has resulted in the formation of two red-mud mound-like deposits. The red-mud deposits at the mouth of the out falls, are not stable and very often red-mud masses are detached from the two main deposits and are transported to the Corinth central basin, by turbidity currents, at a water depth of 850 m and about 17 km away from the main deposits. Thus, at the Antikyra bay, the red-mud has formed a surficial veneer (0.5-2.0 cm) on the sea floor. On the Corinth central basin floor the red mud has formed successive red-mud layers which are interrupted by layers of natural mud. Fifteen gravity cores have been selected from the studied area and a number of bauxite samples have been collected from mines that supply the bauxite processing plant. Red-mud, natural mud and bauxite samples were analyzed for 238 U 226 Ra, 232 Th, 40 K, and 137 Cs by direct gamma spectrometry. The study of radionuclides concentrations has shown that: (a) the enrichment factor of radionuclides in the red-mud in the main deposit at the mouth of the out falls, in relation to bauxite samples, is about 2.0, (b) the enrichment factor of 238 U, 226 Ra and 232 Th in the red-mud in the main deposit and the central basin, in relation to natural sediments below, is visibly higher than 1.0 (2.0-19.0) whilst 40 K exhibits the opposite trend, and (c) the enrichment/dilution factor of radionuclides in the red-mud surficial veneer at the Antikyra Bay, in relation to the natural sediments below, is ranging between 0.4 and 3.5. (author)

  13. The dry closure of Almagrera tailings dam; La clausura seca de la presa de residuos mineros de Almagrera

    Energy Technology Data Exchange (ETDEWEB)

    Justo Alpanes, J. L. de; Durand Neyra, P.; Abel Jimenez, F.; Vazquez Boza, M

    2012-07-01

    After the catastrophic failures of Los Frailes dam at Aznalcollar (Huesca), sensitivity towards the safety of mineral waste deposits in Spain, has increased, forcing mining companies to submit in advance a plan for mine closure when the end of exploitation arrives. However, today the Spanish Autonomous Communities are forced to solve the problem of closure of abandoned mines and tailings dams like Almagrera. We present a mechanical model that reproduces all the operations necessary for the dry closure of Almagrera dam, 37.34 meters high. These operations correspond to aspects such as: a. The placement, above the tailings, of toxic coarse mineral residues, thereby reducing the volume of mining dumps. b. Methods to speed up settlements before placing the cover and, this way, prevent damage to it; for example the placement of band-shaped drains, inside the tailings, after the fill has been placed on them. c. This possible liquefaction of tailings during an earthquake. The model has indicated the necessity of placing rock fill reinforcement downstream. (Author) 6 refs.

  14. Uranium mill tailings and radon

    International Nuclear Information System (INIS)

    Hanchey, L.A.

    1981-01-01

    The major health hazard from uranium mill tailings is presumed to be respiratory cancer resulting from the inhalation of radon daughter products. A review of studies on inhalation of radon and its daughters indicates that the hazard from the tailings is extremely small. If the assumptions used in the studies are correct, one or two people per year in the US may develop cancer as a result of radon exhaled from all the Uranium Mill Tailings Remedial Action Program sites. The remedial action should reduce the hazard from the tailings by a factor of about 100

  15. Uranium mill tailings and radon

    Energy Technology Data Exchange (ETDEWEB)

    Hanchey, L A

    1981-04-01

    The major health hazard from uranium mill tailings is presumed to be respiratory cancer resulting from the inhalation of radon daughter products. A review of studies on inhalation of radon and its daughters indicates that the hazard from the tailings is extremely small. If the assumptions used in the studies are correct, one or two people per year in the United States may develop cancer as a result of radon exhaled from all the Uranium Mill Tailings Remedial Action program sites. The remedial action should reduce the hazard from the tailings by a factor of about 100.

  16. Uranium mill tailings and radon

    Energy Technology Data Exchange (ETDEWEB)

    Hanchey, L A

    1981-01-01

    The major health hazard from uranium mill tailings is presumed to be respiratory cancer resulting from the inhalation of radon daughter products. A review of studies on inhalation of radon and its daughters indicates that the hazard from the tailings is extremely small. If the assumptions used in the studies are correct, one or two people per year in the US may develop cancer as a result of radon exhaled from all the Uranium Mill Tailings Remedial Action Program sites. The remedial action should reduce the hazard from the tailings by a factor of about 100.

  17. Estimation of Jump Tails

    DEFF Research Database (Denmark)

    Bollerslev, Tim; Todorov, Victor

    We propose a new and flexible non-parametric framework for estimating the jump tails of Itô semimartingale processes. The approach is based on a relatively simple-to-implement set of estimating equations associated with the compensator for the jump measure, or its "intensity", that only utilizes...... the weak assumption of regular variation in the jump tails, along with in-fill asymptotic arguments for uniquely identifying the "large" jumps from the data. The estimation allows for very general dynamic dependencies in the jump tails, and does not restrict the continuous part of the process...... and the temporal variation in the stochastic volatility. On implementing the new estimation procedure with actual high-frequency data for the S&P 500 aggregate market portfolio, we find strong evidence for richer and more complex dynamic dependencies in the jump tails than hitherto entertained in the literature....

  18. Average configuration of the geomagnetic tail

    International Nuclear Information System (INIS)

    Fairfield, D.H.

    1979-01-01

    Over 3000 hours of Imp 6 magnetic field data obtained between 20 and 33 R/sub E/ in the geomagnetic tail have been used in a statistical study of the tail configuration. A distribution of 2.5-min averages of B/sub z/ as a function of position across the tail reveals that more flux crosses the equatorial plane near the dawn and dusk flanks (B-bar/sub z/=3.γ) than near midnight (B-bar/sub z/=1.8γ). The tail field projected in the solar magnetospheric equatorial plane deviates from the x axis due to flaring and solar wind aberration by an angle α=-0.9 Y/sub SM/-2.7, where Y/sub SM/ is in earth radii and α is in degrees. After removing these effects, the B/sub y/ component of the tail field is found to depend on interplanetary sector structure. During an 'away' sector the B/sub y/ component of the tail field is on average 0.5γ greater than that during a 'toward' sector, a result that is true in both tail lobes and is independent of location across the tail. This effect means the average field reversal between northern and southern lobes of the tail is more often 178 0 rather than the 180 0 that is generally supposed

  19. Field and modeling study of windblown particles from a uranium mill tailings pile. Interim report

    International Nuclear Information System (INIS)

    Schwendiman, L.C.; Sehmel, G.A.; Horst, T.W.; Thomas, C.W.; Perkins, R.W.

    1979-04-01

    A field study is reported, showing that for a carbonate-leach-process mill tailings pile in the Grants, New Mexico region much of the residual radioactive constituents in the tailings is found associated with particles 7 μm in diameter and smaller. As the tailings material dries, particle attachment and aggregation occurs with the result that radioactive constituents become associated more with larger particles. Soil samples taken at surface and subsurface on radial lines extending from the tailings pile for 5 miles showed the distribution of radium-226 and other radionuclides in the soil. The radeium-226 deposited on the soil was distributed in such a manner that about 1.6 Ci of randon-222 per day enters the atmosphere from this secondary source. The suspension and transport of particles were studied using an array of sampling towers and wind speed and velocity instrumentation that signaled designated samplers at upwind and downwind locations to operate when wind direction and speed criteria were satisfied. Flux of particles in various size ranges was determined as a function of wind speed. The radionuclide content of airborne particles as a function of particle size was measured for some samplers. A significant fraction of airborne radioactive material is associated with respirable particles. 56 figures, 13 tables

  20. Segregation and differential settling in flocculated tailings

    Energy Technology Data Exchange (ETDEWEB)

    Farinato, R.S.; Mahmoudkhani, A.; Fenderson, T.; Watson, P. [Kemira, Atlanta, GA (United States)

    2010-07-01

    Untreated oil sands tailings have a high solids content, have poor dewaterability, and contain no aggregates. This PowerPoint presentation investigated segregation and differential settling in flocculated tailings. Tailings were treated with gypsum and various polymers. Cylinder settling, dynamic rheometry, particle size analysis, and microscopy techniques were used to characterize the composite tailings. The particles sizes of the samples were evaluated in relation to shear rate, bed depth, and treatment. The study showed that the gypsum-treated tailings had small aggregates, size stratification, a high solids content, and poor dewaterability. The polymer N-treated tailings had the lowest solids content, good dewaterability, and weak aggregates. The polymer A-treated tailings had a low solids content, very good dewaterability, and strong aggregates. The addition of a coagulant to the polymer-A treated tailings provided weaker aggregates and a higher solids content. tabs., figs.

  1. Ecotoxicity of Mine Tailings: Unrehabilitated Versus Rehabilitated.

    Science.gov (United States)

    Maboeta, M S; Oladipo, O G; Botha, S M

    2018-05-01

    Earthworms are bioindicators of soil pollution. The ecotoxicity of tailings from selected gold mines in South Africa was investigated utilizing Eisenia andrei bioassays and biomarkers. Samples were obtained from unrehabilitated, rehabilitated and naturally vegetated sites. Biomass, neutral red retention time (NRRT), survival and reproduction were assessed using standardized protocols. Earthworm biomass, NRRT and reproductive success in rehabilitated tailings (comparable to naturally vegetated site) were significantly higher (p tailings. In addition, significantly lower (p tailings compared to the unrehabilitated. Further, significantly lower (p tailings than the rehabilitated and naturally vegetated sites. Overall, reduced ecotoxicity effects were confirmed in rehabilitated compared to unrehabilitated tailings. This suggests that rehabilitation as a post-mining restorative strategy has strong positive influence on mine tailings.

  2. The role of cassiterite controlling arsenic mobility in an abandoned stanniferous tailings impoundment at Llallagua, Bolivia.

    Science.gov (United States)

    Romero, Francisco Martín; Canet, Carles; Alfonso, Pura; Zambrana, Rubén N; Soto, Nayelli

    2014-05-15

    The surface water contamination by potentially toxic elements (PTE) leached from mine tailings is a major environmental concern. However, the formation of insoluble solid phases can control the mobility of PTE, with subsequent decrease of the risk that tailings suppose to the environment. We characterized the tailings from a tin inactive mine in Llallagua, Bolivia in order to assess the risk for surface water quality. These tailings contain high concentrations of PTE, with up to 94,344 mg/kg Fe, 9,135 mg/kg Sn, 4,606 mg/kg As, 1,362 mg/kg Cu, 1,220 mg/kg Zn, 955 mg/kg Pb and 151 mg/kg Cd. Oxidation of sulfide minerals in these tailings generates acid leachates (pH=2.5-3.5), rich in SO4(2-) and dissolved PTE, thereby releasing contaminants to the surface waters. Nevertheless, the concentrations of dissolved Sn, As and Pb in acid leachates are low (Sntailing deposits; it should be the main solid phase controlling Sn and As mobility in the impoundment. Additionally, jarosite and plumbojarosite, identified among the secondary minerals, could also play an important role controlling the mobility of As and Pb. Taking into account (a) the low solubility constants of cassiterite (Ksp=10(-64.2)), jarosite (Ksp=10(-11)) and plumbojarosite (Ksp=10(-28.66)), and (b) the stability of these minerals under acidic conditions, we can conclude that they control the long-term fate of Sn, As and Pb in the studied tailings. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Surficial weathering of iron sulfide mine tailings under semi-arid climate.

    Science.gov (United States)

    Hayes, Sarah M; Root, Robert A; Perdrial, Nicolas; Maier, Raina; Chorover, Jon

    2014-09-15

    Mine wastes introduce anthropogenic weathering profiles to the critical zone that often remain unvegetated for decades after mining cessation. As such, they are vulnerable to wind and water dispersion of particulate matter to adjacent ecosystems and residential communities. In sulfide-rich ore tailings, propagation to depth of the oxidative weathering front controls the depth-variation in speciation of major and trace elements. Despite the prevalence of surficial mine waste deposits in arid regions of the globe, few prior studies have been conducted to resolve the near-surface profile of sulfide ore tailings weathered under semi-arid climate. We investigated relations between gossan oxidative reaction-front propagation and the molecular speciation of iron and sulfur in tailings subjected to weathering under semi-arid climate at an EPA Superfund Site in semi-arid central Arizona (USA). Here we report a multi-method data set combining wet chemical and synchrotron-based X-ray diffraction (XRD) and X-ray absorption near-edge spectroscopy (XANES) methods to resolve the tight coupling of iron (Fe) and sulfur (S) geochemical changes in the top 2 m of tailings. Despite nearly invariant Fe and S concentration with depth (130-140 and 100-120 g kg -1 , respectively), a sharp redox gradient and distinct morphological change was observed within the top 0.5 m, associated with a progressive oxidative alteration of ferrous sulfides to (oxyhydr)oxides and (hydroxy)sulfates. Transformation is nearly complete in surficial samples. Trends in molecular-scale alteration were co-located with a decrease in pH from 7.3 to 2.3, and shifts in Fe and S lability as measured via chemical extraction. Initial weathering products, ferrihydrite and gypsum, transform to schwertmannite, then jarosite-group minerals with an accompanying decrease in pH. Interestingly, thermodynamically stable phases such as goethite and hematite were not detected in any samples, but ferrihydrite was observed even in

  4. Surficial weathering of iron sulfide mine tailings under semi-arid climate

    Science.gov (United States)

    Hayes, Sarah M.; Root, Robert A.; Perdrial, Nicolas; Maier, Raina M.; Chorover, Jon

    2014-09-01

    Mine wastes introduce anthropogenic weathering profiles to the critical zone that often remain unvegetated for decades after mining cessation. As such, they are vulnerable to wind and water dispersion of particulate matter to adjacent ecosystems and residential communities. In sulfide-rich ore tailings, propagation to depth of the oxidative weathering front controls the depth-variation in speciation of major and trace elements. Despite the prevalence of surficial mine waste deposits in arid regions of the globe, few prior studies have been conducted to resolve the near-surface profile of sulfide ore tailings weathered under semi-arid climate. We investigated relations between gossan oxidative reaction-front propagation and the molecular speciation of iron and sulfur in tailings subjected to weathering in a semi-arid climate at an EPA Superfund Site in central Arizona (USA). Here we report a multi-method data set combining wet chemical and synchrotron-based X-ray diffraction (XRD) and X-ray absorption near-edge spectroscopy (XANES) methods to resolve the tight coupling of iron (Fe) and sulfur (S) geochemical changes in the top 2 m of tailings. Despite nearly invariant Fe and S concentration with depth (130-140 and 100-120 g kg-1, respectively), a sharp redox gradient and distinct morphological change was observed within the top 0.5 m, associated with a progressive oxidative alteration of ferrous sulfides to (oxyhydr)oxides and (hydroxy)sulfates. Transformation is nearly complete in surficial samples. Trends in molecular-scale alteration were co-located with a decrease in pH from 7.3 to 2.3, and shifts in Fe and S lability as measured via chemical extraction. Initial weathering products, ferrihydrite and gypsum, transform to schwertmannite, then jarosite-group minerals with an accompanying decrease in pH. Interestingly, thermodynamically stable phases such as goethite and hematite were not detected in any samples, but ferrihydrite was observed even in samples with

  5. Geochemical investigation of Sasa tailings dam material and its influence on the Lake Kalimanci surficial sediments (Republic of Macedonia – preliminary study

    Directory of Open Access Journals (Sweden)

    Petra Vrhovnik

    2011-12-01

    Full Text Available This research is aimed at investigating the mineralogical characteristics of the tailings material and heavy metal contents of the tailings material deposited close to the Sasa Pb-Zn Mine in the Osogovo Mountains (eastern Macedonia and on its possible impact on Lake Kalimanci. The mineral composition of Sasa Mine tailings materialis dominated by quartz, pyrite, galena, sphalerite, magnetite and others. Geochemical analysis was performed in a certified commercial laboratory for the following elements: Mo, Cu, Pb, Zn, Ni, As, Cd, Sb, Bi, Ag, Al, Fe, Mn, S.Analysis revealed very high concentrations of toxic metals in the tailing material – with average values [ mg kg-1]:Mo 2.9, Cu 279, Pb 3975, Zn 5320, Ni 30, As 69, Cd 84, Sb 4.2, Bi 9.4 and Ag 4.1. The multi-element contamination of Sasa Mine tailings material was assigned a pollution index greater of 15, indicating that the tailings material from Sasa Mine contains very high amounts of toxic metals and represents a high environmental risk for surrounding ecosystems. For this reason the influence of discharged tailings dam material into Lake Kalimanci which liesapproximately 12 km lower than Sasa Mine, was also established. Calculated pollution index values for Lake Kalimancisediments vary from 21 to 65 and for Sasa mine surficial tailings dam material from 15 to 60.

  6. Calibration and validation of FEMWATER/FEMWASTE

    International Nuclear Information System (INIS)

    Lafleur, D.W.; Raven, K.G.

    1990-03-01

    The purpose of this study was to evaluate the ability of the FEMWATER/FEMWASTE computer models to simulate groundwater and contaminant transport at Canadian uranium mine tailings sites. The study involved development and calibration of simulation models for the Nordic tailings area, Elliot Lake, Ontario, using historical data. Prediction of pH and radium 226 concentrations were then made and compared to recently collected field data. The models poorly predicted most regions of the current groundwater contaminant plumes. This was attributed to the simplistic treatment of geochemical processes within the model, uncertainty regarding source term configuration, the two-dimensional nature of the flow model and the uncertainties of the geochemical results. Three-dimensional flow models coupled to multi-component geochemical models may be more suitable to assessing migration of contaminated groundwater at uranium mine tailings sites

  7. Environmental de-watering of fluid fine tailings

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, G.W. [Alberta Univ., Edmonton, AB (Canada). Geotechnical Center

    2010-07-01

    This presentation reported on a surface deposition method of dewatering mature fine tailings (MFT). MFTs typically have a solids content of 35 percent. Solids contents of 60 percent or greater have been shown to produce desirable physical properties. Dewatering was considered as a flux boundary problem. Dewatering a 1.0 meter thick profile of MFT with an initial solids content of 35 percent required approximately 200 mm per 1 m{sup 2} of water to exit the boundaries of the profile. The flux boundary conditions were driven by atmospheric forcing events associated with freeze-thaw effects and evaporative drying, and were also influenced by the drainage of liquid water caused by run-off and foundation seepage. The relative contributions of the dewatering mechanisms were discussed and quantified. tabs., figs.

  8. A puzzling migratory detour : Are fueling conditions in Alaska driving the movement of juvenile sharp -tailed sandpipers ?

    Science.gov (United States)

    Lindstrom, A.; Gill, Robert E.; Jamieson, S.E.; McCaffery, B.; Wennerberg, Liv; Wikelski, M.; Klaassen, M.

    2011-01-01

    Making a detour can be advantageous to a migrating bird if fuel-deposition rates at stopover sites along the detour are considerably higher than at stopover sites along a more direct route. One example of an extensive migratory detour is that of the Sharp-tailed Sandpiper (Calidris acuminata), of which large numbers of juveniles are found during fall migration in western Alaska. These birds take a detour of 1500-3400 km from the most direct route between their natal range in northeastern Siberia and nonbreeding areas in Australia. We studied the autumnal fueling rates and fuel loads of 357 Sharp-tailed Sandpipers captured in western Alaska. In early September the birds increased in mass at a rate of only 0.5% of lean body mass day?1. Later in September, the rate of mass increase was about 6% of lean body mass day?1, among the highest values found among similar-sized shorebirds around the world. Some individuals more than doubled their body mass because of fuel deposition, allowing nonstop flight of between 7100 and 9800 km, presumably including a trans-oceanic flight to the southern hemisphere. Our observations indicated that predator attacks were rare in our study area, adding another potential benefit of the detour. We conclude that the most likely reason for the Alaskan detour is that it allows juvenile Sharp-tailed Sandpipers to put on large fuel stores at exceptionally high rates. Copyright ?? The Cooper Ornithological Society 2011.

  9. Review of samples of tailings, soils and stream sediment adjacent to and downstream from the Ruth Mine, Inyo County, California

    Science.gov (United States)

    Rytuba, James J.; Kim, Christopher S.; Goldstein, Daniel N.

    2011-01-01

    The Ruth Mine and mill are located in the western Mojave Desert in Inyo County, California (fig. 1). The mill processed gold-silver (Au-Ag) ores mined from the Ruth Au-Ag deposit, which is adjacent to the mill site. The Ruth Au-Ag deposit is hosted in Mesozoic intrusive rocks and is similar to other Au-Ag deposits in the western Mojave Desert that are associated with Miocene volcanic centers that formed on a basement of Mesozoic granitic rocks (Bateman, 1907; Gardner, 1954; Rytuba, 1996). The volcanic rocks consist of silicic domes and associated flows, pyroclastic rocks, and subvolcanic intrusions (fig. 2) that were emplaced into Mesozoic silicic intrusive rocks (Troxel and Morton, 1962). The Ruth Mine is on Federal land managed by the U.S. Bureau of Land Management (BLM). Tailings from the mine have been eroded and transported downstream into Homewood Canyon and then into Searles Valley (figs. 3, 4, 5, and 6). The BLM provided recreational facilities at the mine site for day-use hikers and restored and maintained the original mine buildings in collaboration with local citizen groups for use by visitors (fig. 7). The BLM requested that the U.S. Geological Survey (USGS), in collaboration with Chapman University, measure arsenic (As) and other geochemical constituents in soils and tailings at the mine site and in stream sediments downstream from the mine in Homewood Canyon and in Searles Valley (fig. 3). The request was made because initial sampling of the site by BLM staff indicated high concentrations of As in tailings and soils adjacent to the Ruth Mine. This report summarizes data obtained from field sampling of mine tailings and soils adjacent to the Ruth Mine and stream sediments downstream from the mine on June 7, 2009. Our results permit a preliminary assessment of the sources of As and associated chemical constituents that could potentially impact humans and biota.

  10. {sup 226}Ra concentrations in crayfish tissues, water, and sediments from the Serpent River Basin in Northeastern Ontario, Canada

    Energy Technology Data Exchange (ETDEWEB)

    Alikhan, M.A. [Laurentian Univ., Sudbury, ON (Canada). Dept of Biology

    1996-12-31

    Lower Serpent River, as well as Elliot, McCarthy and McCabe lakes had highest {sup 226}Ra contamination, Chrisman, Quirke and Whiskey lakes a moderate one, Flack and Semiwhite lakes and the `distant` control, Lake Wanapitei, the lowest. {sup 226}Ra activity in Cambarus robustus tissues was directly related to their background levels. Thus, concentration coefficient (tissue/sediment concentrations) for {sup 226}Ra ranged from 0.53 to 0.74 in highly contaminated Elliot and McCarthy lakes, 0.28 to 0.59 in moderately contaminated Quirke and Whiskey lakes, and from 0.27 to 3.44 in least contaminated Semiwhite and Flack lakes. Among various organs analysed, exoskeleton showed the highest (43.04 - 90.69%) and the tail muscles the lowest (2.95 -17.14%) {sup 226}Ra activity. {sup 226}Ra concentrations in the alimentary canal were considered a part of the ambient environment as they had not been absorbed. 12 refs, 1 fig, 1 tab.

  11. Markov Tail Chains

    OpenAIRE

    janssen, Anja; Segers, Johan

    2013-01-01

    The extremes of a univariate Markov chain with regularly varying stationary marginal distribution and asymptotically linear behavior are known to exhibit a multiplicative random walk structure called the tail chain. In this paper we extend this fact to Markov chains with multivariate regularly varying marginal distributions in Rd. We analyze both the forward and the backward tail process and show that they mutually determine each other through a kind of adjoint relation. In ...

  12. Tales of island tails

    NARCIS (Netherlands)

    Groot, de Alma V.; Oost, Albert P.; Veeneklaas, Roos M.; Lammerts, Evert Jan; Duin, van Willem E.; Wesenbeeck, van Bregje K.

    2016-01-01

    The Frisian islands (Southern North Sea) have extensive island tails, i.e. the entire downdrift side of an island consisting of salt marshes, dunes, beaches and beach plains, and green beaches. Currently, large parts of these tails are ageing and losing dynamics, partly due to human influence.

  13. Tail docking in pigs: a review on its short- and long-term consequences and effectiveness in preventing tail biting

    Directory of Open Access Journals (Sweden)

    Eleonora Nannoni

    2014-02-01

    Full Text Available In spite of European legislation attempting to limit this practice, tail docking is nowadays the only preventive measure against tail biting which is widely adopted by farmers. Docking consists in amputating, usually without anaesthesia or analgesia, the distal part of the tail, in order to reduce its attractiveness and to sensitize it, increasing avoidance behaviour in the bitten pig. Tail docking results in both acute and chronic effects on pig welfare, and its effectiveness in preventing tail biting is limited, since it reduces the symptoms of a behavioural disorder, but does not address the underlying causes. The aim of the present paper is to review the available literature on the effects of tail docking on swine welfare. Although from a practical standpoint the welfare risks arising from tail docking may appear to be negligible compared to those arising during and after tail biting outbreaks, it should be considered that, apart from acute physiological and behavioural responses, tail docking may also elicit long-term effects on weight gain, tail stump sensitivity and animal freedom to express their normal behaviour. Such chronic effects have been poorly investigated so far. Besides, studies evaluating the effectiveness of anaesthetics or analgesic treatments are often conflicting. Within this framework, further research is recommended in order to reduce the acute and chronic pain and discomfort experienced by the animals, until preventive measures (e.g., environmental enrichment, stocking densities are broadly adopted to prevent tail biting.

  14. Meeting the challenge - solutions for managing oil sands tailings: report of the fine tailings fundamentals consortium 1989-1995

    International Nuclear Information System (INIS)

    1996-01-01

    The development and demonstration of effective alternatives for the management of fine tailings in the oil sands industry were discussed in a report describing the work of the Fine Tailings Fundamentals Consortium during the period from 1989 to 1995. The final report of the Consortium is a four-volume publication entitled 'Advances in Oil Sands Tailings Research' which is the state-of-the-art reference to key issues in the reclamation of fine tailings. Government regulations now make it the responsibility of industry to integrate the fine tailings into reclaimed landscapes, so that the final landscape is equal in productive capability to the pre-disturbed state. Impressive progress has been made in understanding the formation of fine tailings and in characterizing their properties, much of it through the work of this Consortium. Fundamental research on the clay particles within fine tailings provides a better understanding of how to manage them. Although there is no 'magic bullet', research has demonstrated that an integrated approach incorporating fine tailings with a variety of elements, uplands, lakes and wetlands, offer the best hope for an environmentally sound solution. figs

  15. The Tail of BPM

    Science.gov (United States)

    Kruba, Steve; Meyer, Jim

    Business process management suites (BPMS's) represent one of the fastest growing segments in the software industry as organizations automate their key business processes. As this market matures, it is interesting to compare it to Chris Anderson's 'Long Tail.' Although the 2004 "Long Tail" article in Wired magazine was primarily about the media and entertainment industries, it has since been applied (and perhaps misapplied) to other markets. Analysts describe a "Tail of BPM" market that is, perhaps, several times larger than the traditional BPMS product market. This paper will draw comparisons between the concepts in Anderson's article (and subsequent book) and the BPM solutions market.

  16. Effects of Tail Clipping on Larval Performance and Tail Regeneration Rates in the Near Eastern Fire Salamander, Salamandra infraimmaculata.

    Directory of Open Access Journals (Sweden)

    Ori Segev

    Full Text Available Tail-tip clipping is a common technique for collecting tissue samples from amphibian larvae and adults. Surprisingly, studies of this invasive sampling procedure or of natural tail clipping--i.e., bites inflicted by predators including conspecifics--on the performance and fitness of aquatic larval stages of urodeles are scarce. We conducted two studies in which we assessed the effects of posterior tail clipping (~30 percent of tail on Near Eastern fire salamander (Salamandra infraimmaculata larvae. In a laboratory study, we checked regeneration rates of posterior tail-tip clipping at different ages. Regeneration rates were hump-shaped, peaking at the age of ~30 days and then decreasing. This variation in tail regeneration rates suggests tradeoffs in resource allocation between regeneration and somatic growth during early and advanced development. In an outdoor artificial pond experiment, under constant larval densities, we assessed how tail clipping of newborn larvae affects survival to, time to, and size at metamorphosis. Repeated measures ANOVA on mean larval survival per pond revealed no effect of tail clipping. Tail clipping had correspondingly no effect on larval growth and development expressed in size (mass and snout-vent length at, and time to, metamorphosis. We conclude that despite the given variation in tail regeneration rates throughout larval ontogeny, clipping of 30% percent of the posterior tail area seems to have no adverse effects on larval fitness and survival. We suggest that future use of this imperative tool for the study of amphibian should take into account larval developmental stage during the time of application and not just the relative size of the clipped tail sample.

  17. Uranium mill tailings stabilization

    International Nuclear Information System (INIS)

    Hartley, J.N.; Koehmstedt, P.L.; Esterl, D.J.; Freeman, H.D.

    1980-02-01

    Uranium mill tailings pose a potential radiation health hazard to the public. Therefore, stabilization or disposal of these tailings in a safe and environmentally sound way is needed to minimize radon exhalation and other environmental hazards. One of the most promising concepts for stabilizing U tailings is the use of asphalt emulsion to contain radon and other hazardous materials within uranium tailings. This approach is being investigated at the Pacific Northwest Laboratory. Results of these studies indicate that a radon flux reduction of greater than 99% can be obtained using either a poured-on/sprayed-on seal (3.0 to 7.0 mm thick) or an admixture seal (2.5 to 12.7 cm thick) containing about 18 wt % residual asphalt. A field test was carried out in June 1979 at the Grand Junction tailings pile in order to demonstrate the sealing process. A reduction in radon flux ranging from 4.5 to greater than 99% (76% average) was achieved using a 15.2-cm (6-in.) admix seal with a sprayed-on top coat. A hydrostatic stabilizer was used to apply the admix. Following compaction, a spray coat seal was applied over the admix as the final step in construction of a radon seal. Overburden was applied to provide a protective soil layer over the seal. Included in part of the overburden was a herbicide to prevent root penetration

  18. Predicting radon flux from uranium mill tailings

    International Nuclear Information System (INIS)

    Freeman, H.D.; Hartley, J.N.

    1983-11-01

    Pacific Northwest Laboratory (PNL), under contract to the US Department of Energy (DOE) Uranium Mill Tailings Remedial Action Project (UMTRAP) office, is developing technology for the design of radon barriers for uranium mill tailings piles. To properly design a radon cover for a particular tailings pile, the radon flux emanating from the bare tailings must be known. The tailings characteristics required to calculate the radon flux include radium-226 content, emanating power, bulk density, and radon diffusivity. This paper presents theoretical and practical aspects of estimating the radon flux from an uranium tailings pile. Results of field measurements to verify the calculation methodology are also discussed. 24 references, 4 figures, 4 tables

  19. Numerical modelling for stability of tailings dams

    OpenAIRE

    Auchar, Muhammad; Mattsson, Hans; Knutsson, Sven

    2013-01-01

    A tailings dam is a large embankment structure that is constructed to store the waste from the mining industry. Stability problems may occur in a tailings dam due to factors such as quick rate of raising, internal erosion and liquefaction. The failure of a tailings dam may cause loss of human life and environmental degradation. Tailings Dams must not only be stable during the time the tailings storage facility is in operation, but also long time after the mine is closed. In Sweden, the licens...

  20. Ion mobility based on column leaching of South African gold tailings dam with chemometric evaluation.

    Science.gov (United States)

    Cukrowska, Ewa M; Govender, Koovila; Viljoen, Morris

    2004-07-01

    New column leaching experiments were designed and used as an alternative rapid screening approach to element mobility assessment. In these experiments, field-moist material was treated with an extracting solution to assess the effects of acidification on element mobility in mine tailings. The main advantage of this version of column leaching experiments with partitioned segments is that they give quick information on current element mobility in conditions closely simulating field conditions to compare with common unrepresentative air-dried, sieved samples used for column leaching experiments. Layers from the tailings dump material were sampled and packed into columns. The design of columns allows extracting leachates from each layer. The extracting solutions used were natural (pH 6.8) and acidified (pH 4.2) rainwater. Metals and anions were determined in the leachates. The concentrations of metals (Ca, Mg, Fe, Mn, Al, Cr, Ni, Co, Zn, and Cu) in sample leachates were determined using ICP OES. The most important anions (NO3-, Cl-, and SO4(2)-) were determined using the closed system izotacophoresis ITP analyser. The chemical analytical data from tailings leaching and physico-chemical data from field measurements (including pH, conductivity, redox potential, temperature) were used for chemometric evaluation of element mobility. Principal factor analysis (PFA) was used to evaluate ions mobility from different layers of tailings dump arising from varied pH and redox conditions. It was found that the results from the partitioned column leaching illustrate much better complex processes of metals mobility from tailings dump than the total column. The chemometric data analysis (PFA) proofed the differences in the various layers leachability that are arising from physico-chemical processes due to chemical composition of tailings dump deposit. Copyright 2004 Elsevier Ltd.

  1. Multichannel thickener of flotation tailings

    Energy Technology Data Exchange (ETDEWEB)

    Kondratenko, A F; Shuliko, A N; Zinchenko, A F

    1983-04-01

    A multichannel thickener of flotation tailings developed by Ukrniiugleobogashchenie is described. Tailings with solid content ranging from 40 to 60 g/l are mixed with flocculation reagents (quantity ratio from 60 to 70 g/l) in a turbulent mixer: waste water with tailings fed to the mixer is divided into three streams, flocculation reagents are batched in stages with each water stream. After turbulent mixing, water, tailings and reagent are fed to the settling chamber. Settling chamber (dimensions 2.4 x 1.5 x 1.0 m) is divided into a number of channels by settling surfaces of 0.35 m/sup 2/ each, inclined at an angle of 55 degrees. Distance between the surfaces is 50 mm. The thickener has a total settling surface of 18.7 m/sup 2/. Water with tailings flows upwards, cleaned water is removed by a separating system and settled tailings move downward and accumulate in the compacting chamber (dimensions 1.5 x 1.5 x 0.9 m). From the compacting chamber thickened slurry with solid content from 90 to 150 g/l is removed by a hydraulic system. During performance testing in some plants preparing coal difficult to wash, thickening efficiency amounted to 100%. The results of performance testing are shown in two tables. Factors which influence thickener productivity are evaluated. (In Russian)

  2. Transport and Deposition of Suspended Soil-Colloids in Saturated Sand Columns

    DEFF Research Database (Denmark)

    Sharma, Anu; Kawamoto, Ken; Møldrup, Per

    2011-01-01

    Understanding colloid mobilization, transport and deposition in the subsurface is a prerequisite for predicting colloid‐facilitated transport of strongly adsorbing contaminants and further developing remedial activities. This study investigated the transport behavior of soil‐colloids extracted from...... caused tailing of colloid BTCs with higher reversible entrapment and release of colloids than high flow velocity. The finer Toyoura sand retained more colloids than the coarser Narita sand at low pH conditions. The deposition profile and particle size distribution of colloids in the Toyoura sand clearly...

  3. Fundamental Investigations into the Infrared Properties of Carbon Nanotubes

    Science.gov (United States)

    2013-01-23

    Vallejo , Rongtao Lu, Judy Wu. Development of Textured Magnesium Oxide Templates on Amorphous Polymer SurfacesUsing Ion-Beam-Assisted Deposition, Applied...Applied Physics Letters 99, 023111 (2011) 18. A. Elliot, Vallejo , R.T. Lu, and J.Z. Wu, “Development of Textured Magnesium Oxides Templates on

  4. Review of samples of sediment, tailings, and waters adjacent to the Cactus Queen gold mine, Kern County, California

    Science.gov (United States)

    Rytuba, James J.; Kim, Christopher S.; Goldstein, Daniel N.

    2011-01-01

    The Cactus Queen Mine is located in the western Mojave Desert in Kern County, California. The Cactus Queen gold-silver (Au-Ag) deposit is similar to other Au-Ag deposits hosted in Miocene volcanic rocks that consist of silicic domes and associated flows, pyroclastic rocks, and subvolcanic intrusions. The volcanic rocks were emplaced onto a basement of Mesozoic silicic intrusive rocks. A part of the Cactus Queen Mine is located on Federal land managed by the U.S. Bureau of Land Management (BLM). Staff from the BLM initially sampled the mine area and documented elevated concentrations of arsenic (As) in tailings and sediment. BLM then requested that the U.S. Geological Survey (USGS), in collaboration with Chapman University, measure and characterize As and other geochemical constituents in sediment, tailings, and waters on the part of the mine on Federal lands. This report is made in response to the request by the BLM, the lead agency mandated to conduct a Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) - Removal Site Investigation (RSI). The RSI applies to the potential removal of As-contaminated mine waste from the Cactus Queen Mine as a means of reducing As release and exposure to humans and biota. This report summarizes data obtained from field sampling of sediments, mine tailings, and surface waters at the Cactus Queen Mine on January 27, 2008. Our results provide a preliminary assessment of the sources of As and associated chemical constituents that could potentially impact humans and biota.

  5. Comparison of the breeding biology of sympatric red-tailed Hawks, White-tailed Hawks, and Crested Caracaras in south Texas

    Science.gov (United States)

    Actkinson, M.A.; Kuvlesky, W.P.; Boal, C.W.; Brennan, L.A.; Hernandez, F.

    2009-01-01

    We compared the breeding biology of sympatric nesting Red-tailed Hawks (Buteo jamaicensis), White-tailed Hawks (Buteo albicaudatus), and Crested Caracaras (Caracara cheriway) in south Texas during 2003 and 2004. We monitored 46 breeding attempts by Red-tailed Hawks, 56 by White-tailed Hawks, and 27 by Crested Caracaras. Observed nesting success was similar for Red-tailed Hawks (62%) and Crested Caracaras (61%), but lower for White-tailed Hawks (51%). Daily survival rates (0.99) were the same for all three species. Red-tailed Hawks and White-tailed Hawks both fledged 1.13 young per nesting pair and Crested Caracaras fledged 1.39 young per nesting pair. All three species nested earlier in 2004 than in 2003; in addition, the overall nesting density of these three species almost doubled from 2003 (1.45 pairs/km2) to 2004 (2.71 pairs/km2). Estimated productivity of all three species was within the ranges reported from other studies. Given extensive and progressive habitat alteration in some areas of south Texas, and the limited distributions of White-tailed Hawks and Crested Caracaras, the presence of large ranches managed for free-range cattle production and hunting leases likely provides important habitat and may be key areas for conservation of these two species. ?? 2009 The Raptor Research Foundation, Inc.

  6. Experience in the transport and disposal of uranium mill tailings from Aldama City to Sierra Pena Blanca in Chihuahua, Mexico

    International Nuclear Information System (INIS)

    Ruiz, M.; Molina, G.; Angeles C, A.; Cruz G, S.; Lizacano C, D.; Reyes, J.; Rojas, V.

    1996-01-01

    In the process of decontamination, transport and disposal of uranium mill tailings, in the state of Chihuahua, Mexico, was necessary the multidisciplinary and multi institutional task to select mainly the site for the final disposal. The uranium mill tailings content Ra-226 which half live time is 1600 years, therefore the site should be adequately stable, a remote place of population, and which containment will survive for thousand of years. The decontamination of site where the uranium mill tailings were 25 years ago, required the application of norms from regulator organism. For the transport of uranium mill tailings was necessary that the vehicles had devices to reduce the dispersion of material in the road. The selection of the site was product of balance between the cost of transport and the final disposal. To typify the site, studies of hydrology, meteorology, ecology, geology and seismology were performed. On the other hand, the decision to locate the deposit in the site was due to dispersion of material by the rain, wind and bowls. (authors). 3 refs., 1 fig., 1 tab

  7. Mineralogy and geochemistry of uranium mill tailings

    International Nuclear Information System (INIS)

    Pagel, M.; Somot, S.

    2002-01-01

    We have investigated three main types of uranium mill tailings: (1) acid mill tailings (Mounana, Gabon), (2) neutralized acid mill tailings (Ecarpiere and Jouac, France) and (3) alkaline mill tailings (Lodeve, France). We have focused especially on radium behaviour which is of major environmental concern in these tailings, but other metals were also studied. It is shown that in type 1 , trapping of 226 Ra by anglesite and barite is dominant whereas in types 2 and 3, 226 Ra is mainly or significantly scavenged by Fe- Mn oxyhydroxides. This study points out the importance of keeping conditions in which these oxyhydroxides will be stable for the long-term. Uranium would be also released during acidification of the tailings. This shows the importance to know more about the behavior of Ra during the crystallization of oxyhydroxides and during tailings diagenesis. Therefore, it is very important to study the sorption of Ra by clay minerals or late authigeneous minerals such as barite. (author)

  8. A guide to the management of tailings facilities

    International Nuclear Information System (INIS)

    Bedard, C.; Ferguson, K.; Gladwin, D.; Lang, D.; Maltby, J.; McCann, M.; Poirier, P.; Schwenger, R.; Vezina, S.; West, S.; Duval, J.; Gardiner, E.; Jansons, K.; Lewis, B.; Matthews, J.; Mchaina, D.; Puro, M.; Siwik, R.; Welch, D.

    1998-01-01

    The 'Guide to the Management of Tailings Facilities' has been developed by the Mining Association of Canada in an effort to provide guidance to its member companies on sound practices for the safe and environmentally responsible management of tailings facilities. The guide is a reference tool to help companies ensure that they are managing their tailings facilities responsibly, integrating environmental and safety considerations in a consistent manner, with continuous improvement in the operation of tailings facilities. The key to managing tailings responsibly is consistent application of engineering capabilities through the full life cycle. The guide provides a basis for the development of customized tailings management systems to address specific needs at individual operations, and deals with environmental impacts, mill tailing characteristics, tailings facility studies and plans, dam and related structure design, and control and monitoring. Aspects relating to tailings facility siting, design, construction, operation, decommissioning and closure are also fully treated. 1 tab., 3 figs

  9. Taming the tailings : dead ducks notwithstanding, extensive research is underway to deal with oilsands tailings in a more efficient manner

    Energy Technology Data Exchange (ETDEWEB)

    Collison, M.

    2008-09-15

    Research is now being conducted to reduce the environmental impacts of oil sands tailing ponds. Alberta's oil sands region contains an estimated 60 km{sup 2} of tailings ponds, which serve as holding basins for recycled water as well as collection sites for materials used in reclamation activities. The ponds contain residual bitumen, production chemicals, and minerals. While some of the water in the ponds can be re-used, mature fine tailings must be contained behind dikes. Every barrel of bitumen produced by the industry results in the creation of 1.5 barrels of mature fine tailings. Natural Resources Canada's CANMET Energy Technology Centre is currently conducting a research program with the University of Alberta to reduce the amounts of tailings produced by the industry. Options for dry stackable tailings are being explored, as well as methods of using the tailings to enhance various oil sands processes. It is hoped that the dry, stackable tailings can be used to help reclaim and rebuild Boreal regions impacted by the oil sands industry. The program is gaining interest due to concerns that leakages from the tailings ponds may pollute aquifers and rivers in a region noted for its water shortages. Research teams are also investigating the use of flocculants to create heavy non-segregated tailings. Researchers are also examining methods of recovering hydrocarbons, titanium, and zircon from the tailings. 3 figs.

  10. Assessing Risks of Mine Tailing Dam Failures

    Science.gov (United States)

    Concha Larrauri, P.; Lall, U.

    2017-12-01

    The consequences of tailings dam failures can be catastrophic for communities and ecosystems in the vicinity of the dams. The failure of the Fundão tailings dam at the Samarco mine in 2015 killed 19 people with severe consequences for the environment. The financial and legal consequences of a tailings dam failure can also be significant for the mining companies. For the Fundão tailings dam, the company had to pay 6 billion dollars in fines and twenty-one executives were charged with qualified murder. There are tenths of thousands of active, inactive, and abandoned tailings dams in the world and there is a need to better understand the hazards posed by these structures to downstream populations and ecosystems. A challenge to assess the risks of tailings dams in a large scale is that many of them are not registered in publicly available databases and there is little information about their current physical state. Additionally, hazard classifications of tailings dams - common in many countries- tend to be subjective, include vague parameter definitions, and are not always updated over time. Here we present a simple methodology to assess and rank the exposure to tailings dams using ArcGIS that removes subjective interpretations. The method uses basic information such as current dam height, storage volume, topography, population, land use, and hydrological data. A hazard rating risk was developed to compare the potential extent of the damage across dams. This assessment provides a general overview of what in the vicinity of the tailings dams could be affected in case of a failure and a way to rank tailings dams that is directly linked to the exposure at any given time. One hundred tailings dams in Minas Gerais, Brazil were used for the test case. This ranking approach could inform the risk management strategy of the tailings dams within a company, and when disclosed, it could enable shareholders and the communities to make decisions on the risks they are taking.

  11. Advanced characterisation of organic matter in oil sands and tailings sands used for land reclamation by Fourier transform-ion cyclotron resonance-mass spectrometry (FT-ICR-MS).

    OpenAIRE

    Mareike Noah; Andrea Vieth-Hillebrand; Heinz Wilkes

    2012-01-01

    The Athabasca region of northern Alberta, Canada, is home to deposits of oil sands containing vast amounts (~ 173 billion barrels) of heavily biodegraded petroleum. Oil sands are recovered by surface mining or by in situ steam injection. The extraction of bitumen from oil sands by caustic hot water processing results in large volumes of fluid tailings, which are stored in on-site settling basins. There the tailings undergo a compaction and dewatering process, producing a slowly densifying sus...

  12. Analysis of Heavy-Tailed Time Series

    DEFF Research Database (Denmark)

    Xie, Xiaolei

    This thesis is about analysis of heavy-tailed time series. We discuss tail properties of real-world equity return series and investigate the possibility that a single tail index is shared by all return series of actively traded equities in a market. Conditions for this hypothesis to be true...... are identified. We study the eigenvalues and eigenvectors of sample covariance and sample auto-covariance matrices of multivariate heavy-tailed time series, and particularly for time series with very high dimensions. Asymptotic approximations of the eigenvalues and eigenvectors of such matrices are found...... and expressed in terms of the parameters of the dependence structure, among others. Furthermore, we study an importance sampling method for estimating rare-event probabilities of multivariate heavy-tailed time series generated by matrix recursion. We show that the proposed algorithm is efficient in the sense...

  13. Monte Carlo-based tail exponent estimator

    Science.gov (United States)

    Barunik, Jozef; Vacha, Lukas

    2010-11-01

    In this paper we propose a new approach to estimation of the tail exponent in financial stock markets. We begin the study with the finite sample behavior of the Hill estimator under α-stable distributions. Using large Monte Carlo simulations, we show that the Hill estimator overestimates the true tail exponent and can hardly be used on samples with small length. Utilizing our results, we introduce a Monte Carlo-based method of estimation for the tail exponent. Our proposed method is not sensitive to the choice of tail size and works well also on small data samples. The new estimator also gives unbiased results with symmetrical confidence intervals. Finally, we demonstrate the power of our estimator on the international world stock market indices. On the two separate periods of 2002-2005 and 2006-2009, we estimate the tail exponent.

  14. Uranium mill tailings remedial action technology

    International Nuclear Information System (INIS)

    Hartley, J.N.; Gee, G.W.

    1984-01-01

    The uranium milling process involves the hydrometallurgical extraction of uranium from ores and the resultant generation of large quantities of waste referred to as tailings. Uranium mill tailings have been identified as requiring remediation because they contain residual radioactive material that is not removed in the milling process. Potential radiation exposure can result from direct contact with the tailings, from radon gas emitted by the tailings, and from radioactive contamination of groundwater. As a result, the technology developed under the US Department of Energy (DOE) Uranium Mill Tailings Remedial Action Project (UMTRAP) and the US Nuclear Regulatory Commission (NRC) Uranium Recovery Program have focused on radon control, groundwater contamination and the long-term protection of the containment system. This paper briefly summarizes the UMTRAP and NRC remedial action technology development. 33 references, 9 figures, 5 tables

  15. The sedimentology and mineralogy of the river uranium deposit near Phuthaditjhaba, Qwa-Qwa

    International Nuclear Information System (INIS)

    Brynard, H.J.; Le Roux, J.P.

    1982-08-01

    A sedimentological and mineralogical investigation was carried out on the River deposit discovered by Mining Corporation (Pty) Ltd in Qwa-Qwa, 15 km south-west of Phuthaditjhaba. The orebody is located in fluvial sandstones of the upper Elliot Formation. Palaeocurrent directions reflect a low- to very low-sinuosity river system with a vector mean azimuth towards 062 degrees. A study of sedimentary structures and grain sizes in cliff sections was supplemented by an analysis of borehole logs, which disclosed the sedimentary environment as a braided river of the Donjek type. Uranium mineralisation at the River prospect is unusually thick, averaging almost 2 m, but lower overall grade than the southern Karoo deposits. Almost 30% of the uranium is present in mudstone and siltstone, and the fact that mineralisation in the sandstone is of similar grade and thickness to that of the former two lithological types suggests that grain sizes played a minor role in the dispersion of the ore fluids. The rocks are mainly of three types, viz. lithic graaywackes, feldspathic graywackes and siltstones, of which calcareous and carbonaceous varieties of the former two occur. Uranium mineralisation is associated mainly with organic carbon which occurs in various modes. A small amount of uranium is present as secondary beta-uranophane which occurs interstitially to detrital grains and in the pores of the clayey matrix and lithic fragments. Uranium is the only trace element of economic significance

  16. Chapter 2. The history of uranium tailings formation in the North of Tajikistan, their current condition. 2.4. Degmai uranium tailings

    International Nuclear Information System (INIS)

    Khakimov, N.; Nazarov, Kh.M.; Mirsaidov, I.U.

    2012-01-01

    Present article is devoted to Degmai uranium tailings. The history of Degmai uranium tailings is presented. The current condition of uranium tailings is described. During the last 6-7 years, together with IAEA experts, monitoring is permanently carried out and the tailings influence on the environment is defined. Radiation and dosimetric investigation results from Degmai tailing' surface (June 2006) are considered.

  17. Risk assessment of tailings facility dam failure

    OpenAIRE

    Hadzi-Nikolova, Marija; Mirakovski, Dejan; Stefanova, Violeta

    2011-01-01

    This paper presents the consequences of tailings facility dam failure and therefore the needs for its risk assessment. Tailings are fine-grained wastes of the mining industry, output as slurries, due to mixing with water during mineral processing. Tailings dams vary a lot as it is affected by: tailings characteristics and mill output, site characteristics as: topography, hydrology, geology, groundwater, seismicity and available material and disposal methods. The talings which accumulat...

  18. Placement of radium/barium sludges in tailings areas

    International Nuclear Information System (INIS)

    Murphy, K.L.; Multamaki, G.E.

    1980-01-01

    Currently radium is removed from uranium mining and milling effluents by the addition of barium chloride to precipitate the radium as radium/barium sulphate. The precipitate is allowed to settle in sedimentation basins prior to discharge of the effluent. The sedimentation basins are not suitable for final disposal of the sludge, and placement of the sludges in the tailings area has been proposed. The geochemical environment of fresh tailings areas was characterized as an acidic, oxidized surface zone underlain by an alkaline, reduced zone comprising the rest of the tailings. The quantity of sludge produced was estimated to be small relative to the quantity of tailings, and therefor a relatively small amount of radium would be added to the tailings disposal area by the addition of sludge. To confirm whether sludge addition affected radionuclide solubilization, laboratory leaching tests were conducted on slurries of acid leach tailings, and sludge-tailings mixtures. Radium in the (Ra,Ba)SO 4 sludge was at least as stable as radium in the tailings, and the sludge was able to absorb radium released from the tailings. The addition of sludge did not affect uranium and thorium solubilization. From these results it appears that the placement of sludge in tailings areas would not adversely affect the stability of radionuclides in the tailings or sludge. (auth)

  19. Evaluation of the grass mixture (Faestuca Rubra, Cynodon Dactylon, Lolium Multiflorum and Pennisetum sp.) as Sb phyto-stabilizer in tailings and Sb-rich soils.

    Science.gov (United States)

    Aurora Armienta, M.; Beltrán-Villavicencio, Margarita; Ruiz-Villalobos, Carlos E.; Labastida, Israel; Ceniceros, Nora; Cruz, Olivia; Aguayo, Alejandra

    2017-04-01

    Green house experiments were carried out to evaluate the growth and Sb assimilation of a grass assemblage: Faestuca Rubra, Cynodon Dactylon, Lolium Multiflorum and Pennisetum sp, in tailings and Sb-rich soils. Tailings and soil samples were obtained at the Mexican historical mining zone of Zimapán, Central México. More than 6 tailings impoundments are located at the town outskirts and constitute a contamination source from windblown and waterborne deposit on soils, besides acid mine drainage. Four substrates were used in the experiments: 100% tailings, 20% tailings + 80% soil, 50% tailings + 50% soil , and a soil sample far from tailings as a background. Concentrations of Sb ranged from 310 mg/kg to 413 mg/kg in tailings. A pH of 7.43, 1.27% organic matter, and high concentrations of N, K and P indicated adequate conditions for plant growth. The grass assemblage was raised during 21 days as indicated by OECD (Organisation for Economic Co-operation and Development) Guideline 208 Terrestrial Plant Test: Seedling Emergence and Seedling Growth Test. The highest Sb concentrations were measured in plants grown on tailings with 139 mg/kg in the aerial part and 883 mg/kg in roots. Concentrations of Sb decreased as the proportion of tailings diminished with 22.1 mg/kg in the aerial part and 10 mg/kg in roots corresponding to the plants grown in the 20 % tailings + 80% soil . Bioaccumulation (BAC) and bioconcentration factors (BF) of plants grown on tailings (BAC= 0.42, BCF=3.93) indicated their suitability as a phyto-stabilization option. The grass mixture may be thus applied to control windblown particulate tailings taking advantage to their tolerance to high Sb levels.

  20. Proceedings of the 15. annual British Columbia MEND ML/ARD workshop : the management of tailings and tailings impoundments

    International Nuclear Information System (INIS)

    2009-02-01

    This Mine Environment Neutral Drainage (MEND) workshop was held to promote the exchange of information and ideas on environmental protection and reclamation associated with mining. The workshop covered a broad spectrum of reclamation issues and the key environmental challenges facing the mining industry, such as acid mine drainage (AMD) control, and metal leaching and acid rock drainage (ML/ARD). The theme for the 2008 workshop was the management of tailings and tailings impoundments. Topics of discussion included hydrogeology and geochemistry; tailings disposal; mitigation; closure plans; and postclosure performance. The emphasis was on full-scale case studies, practical constraints and sustaining successful disposal strategies and remediation. The session on tailings management reviewed overarching policies and practices; methods of subaerial tailings disposal and case studies of tailings management; and detailed investigations of geochemical properties and processes. The conference featured 22 presentations, of which 4 have been catalogued separately for inclusion in this database. refs., tabs., figs

  1. The evolution of tail weaponization in amniotes.

    Science.gov (United States)

    Arbour, Victoria M; Zanno, Lindsay E

    2018-01-31

    Weaponry, for the purpose of intraspecific combat or predator defence, is one of the most widespread animal adaptations, yet the selective pressures and constraints governing its phenotypic diversity and skeletal regionalization are not well understood. Here, we investigate the evolution of tail weaponry in amniotes, a rare form of weaponry that nonetheless evolved independently among a broad spectrum of life including mammals, turtles and dinosaurs. Using phylogenetic comparative methods, we test for links between morphology, ecology and behaviour in extant amniotes known to use the tail as a weapon, and in extinct taxa bearing osseous tail armaments. We find robust ecological and morphological correlates of both tail lashing behaviour and bony tail weaponry, including large body size, body armour and herbivory, suggesting these life-history parameters factor into the evolution of antipredator behaviours and tail armaments. We suggest that the evolution of tail weaponry is rare because large, armoured herbivores are uncommon in extant terrestrial faunas, as they have been throughout evolutionary history. © 2018 The Author(s).

  2. Ecological aspects of microorganisms inhabiting uranium mill tailings

    Science.gov (United States)

    Miller, C.L.; Landa, E.R.; Updegraff, D.M.

    1987-01-01

    Numbers and types of microorganisms in uranium mill tailings were determined using culturing techniques. Arthrobacter were found to be the predominant microorganism inhabiting the sandy tailings, whereas Bacillus and fungi predominated in the slime tailings. Sulfate-reducing bacteria, capable of leaching radium, were isolated in low numbers from tailings samples but were isolated in significantly high numbers from topsoil in contact with the tailings. The results are placed in the context of the magnitude of uranium mill tailings in the United States, the hazards posed by the tailings, and how such hazards could be enhanced or diminished by microbial activities. Patterns in the composition of the microbial population are evaluated with respect to the ecological variables that influence microbial growth. ?? 1987 Springer-Verlag New York Inc.

  3. Tailings management for the twenty-first century

    International Nuclear Information System (INIS)

    Frost, S.E.

    1996-01-01

    The evolution of tailings management at Saskatchewan uranium mines is traced from the fifties to the nineties. Some of the problems with past systems are discussed. The new tailings systems now being proposed for the new operations currently undergoing environmental assessment in Saskatchewan are examined in detail. These new systems represent a change in tailings management philosophy, from keeping tailings high and dry on the surface, to placement of tailings in a low-energy regime within the water table. There they are removed from the active surface environment, avoiding future erosion problems, with a reduced likelihood of suffering intrusion from future human or animal activities. (author). 16 refs., 5 figs

  4. Rehabilitation of uranium tailings impoundments

    International Nuclear Information System (INIS)

    Crawley, A.H.

    1983-01-01

    Under Australian environmental controls relating to the management of uranium tailings, it is no longer acceptable practice to search for a rehabilitation strategy at the end of production when the generation of tailings has ceased. The uranium projects currently in production and those being proposed are tightly regulated by the authorities. The waste management plans must consider site specific factors and must include selection of appropriate disposal sites and design for long term containment. The final encapsulation in engineered facilities must take into account the probable routes to the environment of the tailings. Rehabilitation shoud be undertaken by the mining and milling operators to standards approved by appropriate authorities. Appropriate administrative arrangements are required, by way of technical committees and financial bonds to ensure that agreed standards of rehabilitation may be achieved. Past and present experience with the rehabilitation of uranium tailings impoundments in Australia is discussed

  5. Histone H2A mobility is regulated by its tails and acetylation of core histone tails

    International Nuclear Information System (INIS)

    Higashi, Tsunehito; Matsunaga, Sachihiro; Isobe, Keisuke; Morimoto, Akihiro; Shimada, Tomoko; Kataoka, Shogo; Watanabe, Wataru; Uchiyama, Susumu; Itoh, Kazuyoshi; Fukui, Kiichi

    2007-01-01

    Histone tail domains play important roles in cellular processes, such as replication, transcription, and chromosome condensation. Histone H2A has one central and two tail domains, and their functions have mainly been studied from a biochemical perspective. In addition, analyses based on visualization have been employed for functional analysis of some chromatin proteins. In this study, we analyzed histone H2A mobility in vivo by two-photon FRAP, and elucidated that the histone H2A N- and C-terminal tails regulate its mobility. We found that histone H2A mobility was increased following treatment of host cells with a histone deacetylase inhibitor. Our results support a model in which core histone tails directly regulate transcription by interacting with nucleosome DNA via electrostatic interactions

  6. Callus induction and biomass accumulation in vitro in explants from chokeberry (Aronia melanocarpa (Michx. Elliot fruit

    Directory of Open Access Journals (Sweden)

    Tatiana I. Calalb

    2014-09-01

    Full Text Available In this study, the following features were determined: biological (the optimal histogen as explant and the optimal age of donor fruit, biotechnological (type, dosage and combination of growth regulators supplements in culture medium Murashige and Skoog as well as sucrose dosage, and physical (light regime, to induce callusing and biomass accumulation in vitro from the succulent chokeberry (Aronia melanocarpa (Michx. Elliot fruit. It turned out that it was much easier to induce callus from explants composed of the epicarp and hypoderm cut from fruits at 50–60 days after flowering. The role of light regime and varied supplementation of the basic MS medium with different doses of growth regulators was established; they resulted in four pigmented carpomass: violet, cream-pink, cream-white and green. The best combinations for the proliferation of fruit callus were culture media with 0.2–2.5 mg × dm-3 2,4-D+0.5 mg × dm-3 KIN +60 g × dm-3sucrose, while for fruit biomass accumulation enriched with phenolic substances – 2.5–3.5 mg × dm-3 NAA+0.5 mg × dm-3 KIN+60 g × dm-3sucrose. The chemical study of phenolic compounds by HPLC coupled with the mass spectrometry method identified chlorogenic acid, hiperozide, quercetrin, isoquercitrin and rutozide quantitatively and qualitatively in all pigmented carpomass and fruits; an exception is p-coumaric present only qualitatively in green carpomass and absent in fruit and quercetol absent in green carpomass.

  7. Cylinder Symmetric Measures with the Tail Property

    NARCIS (Netherlands)

    Balkema, A.A.

    2006-01-01

    Abstract: A Pareto distribution has the property that any tail of the distribution has the same shape as the original distribution. The exponential distribution and the uniform distribution have the tail property too. The tail property characterizes the univariate generalized Pareto distributions.

  8. Virtual reality in simulation of operational procedures in radioactive waste deposits

    International Nuclear Information System (INIS)

    Freitas, Victor Goncalves Gloria

    2016-01-01

    One of the biggest problems in the nuclear area are still the radioactive waste generated in the various applications of this form of energy, all these tailings are stored in warehouses that often are monitored and restructured for better allocation of then. These tailings are stored until it is safe to release into the environment. This work presents a methodology based on virtual reality, for the development of virtual deposits of radioactive waste in order to enable virtual simulations in these deposits. As application will be developed virtually the nuclear waste repository located at the Institute of Nuclear Engineering IEN/CNEN. The development of a virtual warehouse, more specifically, makes it possible to simulate/train the allocation and reallocation of materials with low and medium level of radioactivity, seen the possibility of locomotion of virtual objects and dynamic calculation of the rate of radiation in this environment. Using this methodology it also possible know the accumulated dose, by the virtual character, during the procedures run in the virtual environment. (author)

  9. Radon emanation characteristics of uranium mill tailings

    International Nuclear Information System (INIS)

    Nielson, K.K.; Freeman, H.D.; Hartley, J.N.; Mauch, M.L.; Rogers, V.C.

    1982-01-01

    Radon emanation from uranium mill tailings was examined with respect to the mechanisms of emanation and the physical properties of the tailings which affect emanation. Radon emanation coefficients were measured at ambient moisture on 135 samples from the 1981 field test site at the Grand Junction tailings pile. These coefficients showed a similar trend with moisture to those observed previously with uranium ores, and averaged 0.10 + or - 0.02 at dryness and 0.38 + or - 0.04 for all samples having greater than five weight-percent moisture. Small differences were noted between the maximum values of the coefficients for the sand and slime fractions of the tailings. Separate measurements on tailings from the Vitro tailings pile exhibited much lower emanation coefficients for moist samples, and similar coefficients for dry samples. Alternative emanation measurement techniques were examined and procedures are recommended for use in future work

  10. Elliot Lake study: factors affecting the uranium mine working environment prior to the introduction of current ventilation practices

    International Nuclear Information System (INIS)

    1985-03-01

    A study was carried out to assist in the retrospective assessment of the underground environment that existed in the Elliot Lake uranium mines in the late 1950's and early 1960's. The environmental conditions and work practices of the late 1950's were established by a combination of literature review and interviews with veteran miners. The practices of the 1950's were imitated in a pilot raise, and extensive measurements of the radiation environment were made. Realistic values of radon and thoron daughter production and removal rates were obtained. The computer model demonstrated that it could reproduce all the observed features of the radiation environment given realistic input parameters. A realistic time and space dependent computer model was used to calculate and compare the average expsoure of the miner in the 1950's with the exposure that would be expected from contemporary measurements, and with that of the miner today. The calculated exposure is about half of that expected from contemporary measurements, which gives assurance that previous exposures for pilot raise miners were not underestimated. Relative to today's miner, the average exposure of the typical raise miner of the 1950's is estimated as three times higher for radon daughters, equal for thoron daughters, equal for exposure to gamma radiation, but much higher for uranium and quartz dust

  11. Vat leaching of gold ores and utilization of the tailings; Kinkoseki no vat leaching to koshi no yuko riyo

    Energy Technology Data Exchange (ETDEWEB)

    Hosooka, T. [Nippon Clay Mining Co. Ltd., Tokyo (Japan); Miyagawa, H. [Mitsui Mining and Smelting Co. Ltd., Tokyo (Japan)

    1996-01-25

    Mitsui Kushikino Mine previously processed two gold ores from Kushikino and Iwato ore deposits by the all slime cyanidation method, where the ores were ground to fine size smaller than 75 {mu}m and leached with sodium, cyanide. A large amount of slimes were produced as waste and discarded in tailings ponds. To save the costs of grinding and waste treatment it is desirable to process coarse sized ores. The Iwato ore is gold and silver bearing silicified porous rock. As most gold and silver in the Iwato ore are concentrated in the pores, leaching of coarse sized ore is expected to be possible. Laboratory tests and pilot plant tests of vat leaching for the Iwato ore were carried out using 0.15-8.0 mm feed. These results showed that the gold dissolution rate was similar to that by the all slime cyanidation and the decrease in gold recovery was a few %. The properties of these tailings can be used in fine aggregate of concrete. Based on the results vat leaching of the Iwato ore was adopted in the plant. The tailings are sold and used as fine aggregate. Utilization of slime tailings from the other ores was also developed and they are used as flux in copper smelters. Now, there is no tailings pond at Mitsui Kushikino Mine. 9 refs., 10 figs., 5 tabs.

  12. Tail-assisted pitch control in lizards, robots and dinosaurs.

    Science.gov (United States)

    Libby, Thomas; Moore, Talia Y; Chang-Siu, Evan; Li, Deborah; Cohen, Daniel J; Jusufi, Ardian; Full, Robert J

    2012-01-04

    In 1969, a palaeontologist proposed that theropod dinosaurs used their tails as dynamic stabilizers during rapid or irregular movements, contributing to their depiction as active and agile predators. Since then the inertia of swinging appendages has been implicated in stabilizing human walking, aiding acrobatic manoeuvres by primates and rodents, and enabling cats to balance on branches. Recent studies on geckos suggest that active tail stabilization occurs during climbing, righting and gliding. By contrast, studies on the effect of lizard tail loss show evidence of a decrease, an increase or no change in performance. Application of a control-theoretic framework could advance our general understanding of inertial appendage use in locomotion. Here we report that lizards control the swing of their tails in a measured manner to redirect angular momentum from their bodies to their tails, stabilizing body attitude in the sagittal plane. We video-recorded Red-Headed Agama lizards (Agama agama) leaping towards a vertical surface by first vaulting onto an obstacle with variable traction to induce a range of perturbations in body angular momentum. To examine a known controlled tail response, we built a lizard-sized robot with an active tail that used sensory feedback to stabilize pitch as it drove off a ramp. Our dynamics model revealed that a body swinging its tail experienced less rotation than a body with a rigid tail, a passively compliant tail or no tail. To compare a range of tails, we calculated tail effectiveness as the amount of tailless body rotation a tail could stabilize. A model Velociraptor mongoliensis supported the initial tail stabilization hypothesis, showing as it did a greater tail effectiveness than the Agama lizards. Leaping lizards show that inertial control of body attitude can advance our understanding of appendage evolution and provide biological inspiration for the next generation of manoeuvrable search-and-rescue robots.

  13. ITER alpha particle diagnostics using knock-on ion tails

    International Nuclear Information System (INIS)

    Fisher, R.K.; Parks, P.B.; McChesney, J.M.

    1995-09-01

    Alpha particles will play a critical role in the physics and successful operation of ITER. Achieving fusion ignition requires that the α particles created by deuterium-tritium (D-T) reactions deposit a large fraction of their energy in the reacting plasma before they are lost. Toroidal field ripple can localize any alpha particle losses and cause first wall damage. We have proposed a new method of measuring the fast confined α-particle distribution in a reacting plasma. The same elastic collisions that transfer the alpha energy to the D-T plasma ions and allow fusion ignition will also create a high energy tail on the deuterium and tritium ion energy distributions. Some of these energetic tail ions will undergo fusion reactions with the background plasma producing neutrons whose energy is increased significantly above 14 MeV due to the kinetic energy of the reacting ions. Measurement of this high energy tail on the D-T neutron distribution as a function of plasma minor radius would provide information on the alpha density profile with a time response equal to the ion slowing-down time. Although this technique may provide only limited information on the α-particle energy distribution, experimental studies of fast ions on existing tokamaks have shown that the observed slowing-down is essentially classical. Hence the α-energy distribution is expected to be classical except in situations where the α-confinement is poor. The confinement of α's can be affected by ripple losses and a number of instabilities. Toroidal field ripple can cause both prompt orbit losses and stochastic ripple diffusion losses. Magnetohydrodynamic activity, including fishbone instabilities, toroidal Alfven eigenmodes, and sawtooth oscillations, may also affect alpha confinement. The diagnostic proposed here, by monitoring the confined alpha population, can provide valuable information on the confinement of fast alphas in a reacting plasma

  14. A qualitative evaluation of long-term processes governing the behaviour of uranium mill tailings placed in deep lakes

    International Nuclear Information System (INIS)

    McKee, Paul; Snodgrass, William; Lush, D.L.; Ross, P.

    1982-03-01

    The emplacement of uranim mill tailings in deep lakes may provide an acceptable method of tailings disposal at certain sites in Canada. Disposal in a depositional environment typical of deep lakes appears to offer greater prospects for long-term stability than present methods of land-based management. From the regulatory point of view, it is necessary to know which factors should be taken into account in assessing the acceptability of such an approach. This report examines the environmental variables governing the behaviour of radionuclides and trace elements in the groundwater systems, lake water, and finally in the biosphere over the short and long-term. Physical, chemical and biological factors are each considered. Conclusions are presented in terms of points for and against disposal in deep lakes

  15. Reclamation and closure of an oil sands tailings facility

    Energy Technology Data Exchange (ETDEWEB)

    Sobkowicz, J. [Thurber Engineering Ltd., Calgary, AB (Canada); Morgenstern, N. [Alberta Univ., Edmonton, AB (Canada)

    2010-07-01

    This PowerPoint presentation discussed methods of ensuring the successful reclamation of oil sands tailings facilities. Tailings should be reclaimed as mining proceeds in order to avoid an excessive accumulation of fluid fine tailings (FFT). The volume of mature fine tailings (MFT) in ponds should be limited in order to ensure effective tailings management. The reclaimed landforms should have good geotechnical stability and be comprised of self-sustaining native vegetation. Strength is needed to allow for timely capping and initial reclamation, and stiffness is required to minimize future settlement and to allow for the construction of a closure landscape. Reclamation strategies were presented for fines-dominated tailings; sand-depleted tailings; and sand-dominated tailings. Energy Resources Conservation Board (ERCB) criteria for tailings reclamation were discussed, and various monitoring and performance assessment strategies were presented. tabs., figs.

  16. Environmental geochemistry of abandoned flotation tailing reservior from the Tonglvshan Fe-Cu sulfide mine in Daye, Central China.

    Science.gov (United States)

    Guo, Y; Bao, Z Y; Deng, Y M; Ma, Z Z; Yan, S

    2011-07-01

    This study investigated metals of tailings from Tonglvshan mine in Daye and assessed the effect of metal contamination in water and sediment near the tailing reservoir. The concentration of copper, lead, zinc, cadmium, chromium and nickel was measured in deposit samples taken from a profile in an abandoned flotation tailing reservoir, as well as in water and sediment samples near the reservoir. The results of this study indicate that copper concentration ranges from 780 to 4390 mg/kg, 2-10 times higher than the limit values in soil, while the contents of other metals are below the limit values. Metal levels in water and sediments are high and varied widely in different sampling sites. The mean concentrations of copper, lead, zinc, cadmium, chromium and nickel in waters are 27.76, 2.28, 8.20, 0.12, 5.30 and 3.04 mg/L, while those in sediments are 557.65, 96.95, 285.20, 0.92, 94.30 and 4.75 mg/kg, respectively. All of the results indicate that the environment near the tailing reservoir is polluted to some extent by some kinds of metals, especially by copper, lead, zinc and cadmium, which may be caused not only by some discharge sources of metals, but also by life garbage and sewage.

  17. On the average configuration of the geomagnetic tail

    International Nuclear Information System (INIS)

    Fairfield, D.H.

    1978-03-01

    Over 3000 hours of IMP-6 magnetic field data obtained between 20 and 33 R sub E in the geomagnetic tail have been used in a statistical study of the tail configuration. A distribution of 2.5 minute averages of B sub Z as a function of position across the tail reveals that more flux crosses the equatorial plane near the dawn and dusk flanks than near midnight. The tail field projected in the solar magnetospheric equatorial plane deviates from the X axis due to flaring and solar wind aberration by an angle alpha = -0.9 y sub SM - 1.7, where y/sub SM/ is in earth radii and alpha is in degrees. After removing these effects the Y component of the tail field is found to depend on interplanetary sector structure. During an away sector the B/sub Y/ component of the tail field is on average 0.5 gamma greater than that during a toward sector, a result that is true in both tail lobes and is independent of location across the tail

  18. Proceedings of the 2. international oil sands tailings conference

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2010-07-01

    The tailings produced by oil sands extraction processes pose significant threats to the surrounding environment in addition to releasing greenhouse gases (GHGs) into the atmosphere. Recent directives have been established to reduce the amount of tailings produced at oil sands operations, and to ensure that tailings ponds are reclaimed in the most effective manner. This conference provided a forum for researchers and industry experts to discuss issues related to the management and reclamation of oil sands tailings. New technologies for dewatering tailings ponds were presented, and methods of analyzing the chemical properties of tailings were reviewed. The conference was divided into the following 7 sessions: (1) tailings properties, (2) tailings dewatering, (3) new concepts, (4) water and chemistry, (5) soft tailings stabilization and reclamation, (6) water treatment, and (7) new concepts 2. The conference featured 44 presentations, all of which have been catalogued separately for inclusion in this database. tabs., figs.

  19. Effects of climate change on nutrition and genetics of White-tailed Ptarmigan

    Science.gov (United States)

    Oyler-McCance, Sara J.; Stricker, Craig A.; St. John, Judy; Braun, Clait E.; Wann, Gregory T.; Aldridge, Cameron L.; Sandercock, Brett K.; Martin, Kathy; Segelbacher, Gernot

    2011-01-01

    White-tailed Ptarmigan (Lagopus leucura) are well suited as a focal species for the study of climate change because they are adapted to cool, alpine environments that are expected to undergo unusually rapid climate change. We compared samples collected in the late 1930s, the late 1960s, and the late 2000s using molecular genetic and stable isotope methods in an effort to determine whether White-tailed Ptarmigan on Mt. Evans, Colorado, have experiences recent environmental changes resulting in shifts in genetic diversity, gene frequency, and nutritional ecology. We genotyped 115 individuals spanning the three time periods, using nine polymorphic microsatellite loci in our genetic analysis. These samples were also analyzed for stable carbon and nitrogen isotopic composition. We found a slight trend of lower heterozygosity through time, and allelic richness values were significantly lower in more recent times, but not significantly using an alpha of 0.05 (P 13C and δ15N values decreased significantly across time periods, whereas the range in isotope values increased consistently from the late 1930s to the late time periods. Inferred changes in the nutritional ecology of White-tailed Ptarmigan on Mt. Evans relate primarily to increased atmospheric deposition of nutrients that likely influenced foraging habits and tundra plant composition and nutritional quality. Future work seeks to integrate genetic and isotopic data with long-term demographics to develop a detailed understanding of the interaction among environmental stressors on the long-term viability of ptarmigan populations.

  20. Unique structural features facilitate lizard tail autotomy

    DEFF Research Database (Denmark)

    Sanggaard, Kristian W; Danielsen, Carl Chr; Wogensen, Lise

    2012-01-01

    Autotomy refers to the voluntary shedding of a body part; a renowned example is tail loss among lizards as a response to attempted predation. Although many aspects of lizard tail autotomy have been studied, the detailed morphology and mechanism remains unclear. In the present study, we showed...... that tail shedding by the Tokay gecko (Gekko gecko) and the associated extracellular matrix (ECM) rupture were independent of proteolysis. Instead, lizard caudal autotomy relied on biological adhesion facilitated by surface microstructures. Results based on bio-imaging techniques demonstrated that the tail...

  1. Health risks from uranium mill tailings

    International Nuclear Information System (INIS)

    Russell, J.L.

    1992-01-01

    This paper reviews the risk to public health and the environment from uranium mill tailings. The steps taken by the Environmental Protection Agency (EPA) to reduce this risk from tailing are summarized

  2. Big picture thinking in oil sands tailings disposal

    Energy Technology Data Exchange (ETDEWEB)

    Boswell, J. [Thurber Engineering Ltd., Calgary, AB (Canada)

    2010-07-01

    This PowerPoint presentation discussed methods of disposing oil sands tailings. Oil sands operators are currently challenged by a variety of legislative and environmental factors concerning the creation and disposal of oil sands tailings. The media has focused on the negative ecological impact of oil sands production, and technical issues are reducing the effect of some mitigation processes. Operators must learn to manage the interface between tailings production and removal, the environment, and public opinion. The successful management of oil sand tailings will include procedures designed to improve reclamation processes, understand environmental laws and regulations, and ensure that the cumulative impacts of tailings are mitigated. Geotechnical investigations, engineering designs and various auditing procedures can be used to develop tailings management plans. Environmental screening and impact assessments can be used to develop sustainable solutions. Public participation and environmental mediation is needed to integrate the public, environmental and technical tailings management strategies. Operators must ensure public accountability for all stakeholders. tabs., figs.

  3. Quasi-steady state aerodynamics of the cheetah tail

    Directory of Open Access Journals (Sweden)

    Amir Patel

    2016-08-01

    Full Text Available During high-speed pursuit of prey, the cheetah (Acinonyx jubatus has been observed to swing its tail while manoeuvring (e.g. turning or braking but the effect of these complex motions is not well understood. This study demonstrates the potential of the cheetah's long, furry tail to impart torques and forces on the body as a result of aerodynamic effects, in addition to the well-known inertial effects. The first-order aerodynamic forces on the tail are quantified through wind tunnel testing and it is observed that the fur nearly doubles the effective frontal area of the tail without much mass penalty. Simple dynamic models provide insight into manoeuvrability via simulation of pitch, roll and yaw tail motion primitives. The inertial and quasi-steady state aerodynamic effects of tail actuation are quantified and compared by calculating the angular impulse imparted onto the cheetah's body and its shown aerodynamic effects contribute to the tail's angular impulse, especially at the highest forward velocities.

  4. Research on uranium tailings disposal technology at CANMET, Ottawa

    International Nuclear Information System (INIS)

    Skeaff, J.M.; Ritcey, G.M.; Jongejan, A.; Silver, M.

    1982-01-01

    In this paper, results from three continuing investigations at CANMET on uranium tailings management are presented. These investigations are: cleaning of tailings by flotation, conversion of municipal wastes into compost for use as topsoil on uranium tailings, methods for the chemical fixation of uranium tailings and a laboratory determination of the rate of release of environmental contaminants from uranium tailings

  5. Consistency based correlations for tailings consolidation

    Energy Technology Data Exchange (ETDEWEB)

    Azam, S.; Paul, A.C. [Regina Univ., Regina, SK (Canada). Environmental Systems Engineering

    2010-07-01

    The extraction of oil, uranium, metals and mineral resources from the earth generates significant amounts of tailings slurry. The tailings are contained in a disposal area with perimeter dykes constructed from the coarser fraction of the slurry. There are many unique challenges pertaining to the management of the containment facilities for several decades beyond mine closure that are a result of the slow settling rates of the fines and the high standing toxic waters. Many tailings dam failures in different parts of the world have been reported to result in significant contaminant releases causing public concern over the conventional practice of tailings disposal. Therefore, in order to reduce and minimize the environmental footprint, the fluid tailings need to undergo efficient consolidation. This paper presented an investigation into the consolidation behaviour of tailings in conjunction with soil consistency that captured physicochemical interactions. The paper discussed the large strain consolidation behaviour (volume compressibility and hydraulic conductivity) of six fine-grained soil slurries based on published data. The paper provided background information on the study and presented the research methodology. The geotechnical index properties of the selected materials were also presented. The large strain consolidation, volume compressibility correlations, and hydraulic conductivity correlations were provided. It was concluded that the normalized void ratio best described volume compressibility whereas liquidity index best explained the hydraulic conductivity. 17 refs., 3 tabs., 4 figs.

  6. Geophysical applications for oil sand mine tailings management

    Energy Technology Data Exchange (ETDEWEB)

    Parker, D.; Bauman, P. [WorleyParsons, Calgary, AB (Canada)

    2009-07-01

    Geophysical techniques are applied throughout a mine's life cycle to facilitate siting, constructing and monitoring of tailings dumps and ponds. This presentation described 3 case studies from the Athabasca region in northeast Alberta that demonstrated some of the concerns associated with oil sand mine tailings, and the information that geophysical surveys can provide. The objectives of these studies were to determine the lateral and depth extents of elevated conductivities of soil and groundwater that have high salt concentration from the tailings sand pore fluid. Due to high chloride concentrations within the tailings material, salt within the root zone may affect vegetation. A terrain conductivity survey was designed to map the lateral extents of salinity impact, while an electrical resistivity tomography (ERT) survey was used to delineate the tailings sand leachate at depth. The proper management of oil sand tailings facilities is vital to the life cycle of a mine. It was concluded that geophysical techniques can be instrumental in managing several engineering and environmental challenges, from Pleistocene channel mapping, to tailings pond settling characteristics, to reclaiming tailings sands. 1 ref., 7 figs.

  7. Engineering assessment of inactive uranium mill tailings

    Energy Technology Data Exchange (ETDEWEB)

    1981-07-01

    The Grand Junction site has been reevaluated in order to revise the October 1977 engineering assessment of the problems resulting from the existence of radioactive uranium mill tailings at Grand Junction, Colorado. This engineering assessment has included the preparation of topographic maps, the performance of core drillings and radiometric measurements sufficient to determine areas and volumes of tailings and radiation exposures of individuals and nearby populations, the investigations of site hydrology and meteorology, and the evaluation and costing of alternative corrective actions. Radon gas released from the 1.9 million tons of tailings at the Grand Junction site constitutes the most significant environmental impact, although windblown tailings and external gamma radiation are also factors. The eight alternative actions presented herein range from millsite and off-site decontamination with the addition of 3 m of stabilization cover material (Option I), to removal of the tailings to remote disposal sites and decontamination of the tailings site (Options II through VIII). Cost estimates for the eight options range from about $10,200,000 for stabilization in-place to about $39,500,000 for disposal in the DeBeque area, at a distance of about 35 mi, using transportation by rail. If transportation to DeBeque were by truck, the cost estimated to be about $41,900,000. Three principal alternatives for the reprocessing of the Grand Junction tailings were examined: (a) heap leaching; (b) treatment at an existing mill; and (c) reprocessing at a new conventional mill constructed for tailings reprocessing. The cost of the uranium recovered would be about $200/lb by heap leach and $150/lb by conventional plant processes. The spot market price for uranium was $25/lb early in 1981. Therefore, reprocessing the tailings for uranium recovery appears not to be economically attractive.

  8. Engineering assessment of inactive uranium mill tailings

    International Nuclear Information System (INIS)

    1981-07-01

    The Grand Junction site has been reevaluated in order to revise the October 1977 engineering assessment of the problems resulting from the existence of radioactive uranium mill tailings at Grand Junction, Colorado. This engineering assessment has included the preparation of topographic maps, the performance of core drillings and radiometric measurements sufficient to determine areas and volumes of tailings and radiation exposures of individuals and nearby populations, the investigations of site hydrology and meteorology, and the evaluation and costing of alternative corrective actions. Radon gas released from the 1.9 million tons of tailings at the Grand Junction site constitutes the most significant environmental impact, although windblown tailings and external gamma radiation are also factors. The eight alternative actions presented herein range from millsite and off-site decontamination with the addition of 3 m of stabilization cover material (Option I), to removal of the tailings to remote disposal sites and decontamination of the tailings site (Options II through VIII). Cost estimates for the eight options range from about $10,200,000 for stabilization in-place to about $39,500,000 for disposal in the DeBeque area, at a distance of about 35 mi, using transportation by rail. If transportation to DeBeque were by truck, the cost estimated to be about $41,900,000. Three principal alternatives for the reprocessing of the Grand Junction tailings were examined: (a) heap leaching; (b) treatment at an existing mill; and (c) reprocessing at a new conventional mill constructed for tailings reprocessing. The cost of the uranium recovered would be about $200/lb by heap leach and $150/lb by conventional plant processes. The spot market price for uranium was $25/lb early in 1981. Therefore, reprocessing the tailings for uranium recovery appears not to be economically attractive

  9. Four tails problems for dynamical collapse theories

    Science.gov (United States)

    McQueen, Kelvin J.

    2015-02-01

    The primary quantum mechanical equation of motion entails that measurements typically do not have determinate outcomes, but result in superpositions of all possible outcomes. Dynamical collapse theories (e.g. GRW) supplement this equation with a stochastic Gaussian collapse function, intended to collapse the superposition of outcomes into one outcome. But the Gaussian collapses are imperfect in a way that leaves the superpositions intact. This is the tails problem. There are several ways of making this problem more precise. But many authors dismiss the problem without considering the more severe formulations. Here I distinguish four distinct tails problems. The first (bare tails problem) and second (structured tails problem) exist in the literature. I argue that while the first is a pseudo-problem, the second has not been adequately addressed. The third (multiverse tails problem) reformulates the second to account for recently discovered dynamical consequences of collapse. Finally the fourth (tails problem dilemma) shows that solving the third by replacing the Gaussian with a non-Gaussian collapse function introduces new conflict with relativity theory.

  10. A Note on Upper Tail Behavior of Liouville Copulas

    Directory of Open Access Journals (Sweden)

    Lei Hua

    2016-11-01

    Full Text Available The family of Liouville copulas is defined as the survival copulas of multivariate Liouville distributions, and it covers the Archimedean copulas constructed by Williamson’s d-transform. Liouville copulas provide a very wide range of dependence ranging from positive to negative dependence in the upper tails, and they can be useful in modeling tail risks. In this article, we study the upper tail behavior of Liouville copulas through their upper tail orders. Tail orders of a more general scale mixture model that covers Liouville distributions is first derived, and then tail order functions and tail order density functions of Liouville copulas are derived. Concrete examples are given after the main results.

  11. Solar wind interaction with type-1 comet tails

    International Nuclear Information System (INIS)

    Ershkovich, A.I.

    1977-01-01

    A comet tail is considered as a plasma cylinder separated by a tangential discontinuity surface from the solar wind. Under typical conditions a comet tail boundary is shown to undergo the Kelvin-Helmholtz instability. With infinite amplitude the stabilizing effect of the magnetic field increases, and waves become stable. The proposed model supplies the detailed quantitative description of helical waves observed in type-1 comet tails. This theory enables the evaluation of the comet tail magnetic field by means of the observations of helical waves. The magnetic field in the comet tail turns out to be of the order of the interplanetary field. This conclusion seems to be in accordance with Alfven's idea that the magnetic field in type-1 comet tails is a captured interplanetary field. (Auth.)

  12. Uranium mill tailings

    International Nuclear Information System (INIS)

    McLaren, L.H.

    1982-11-01

    This bibliography contains information on uranium mill tailings included in the Department of Energy's Energy Data Base from January 1981 through October 1982. The abstracts are grouped by subject category as shown in the table of contents. Entries in the subject index also facilitate access by subject, e.g., Mill Tailings/Radiation Hazards. Within each category the arrangement is by report number for reports, followed by nonreports in reverse chronological order. These citations are to research reports, journal articles, books, patents, theses, and conference papers from worldwide sources. Five indexes, each preceded by a brief description, are provided: Corporate Author, Personal Author, Subject, Contract Number, and Report Number. (335 abstracts)

  13. AL-PAM assisted filtration of mature fine tailings produced from oil sands development

    Energy Technology Data Exchange (ETDEWEB)

    Alamgir, A.; Masliyah, J.; Xu, Z. [Alberta Univ., Edmonton, AB (Canada). Dept. of Chemical and Materials Engineering

    2010-07-01

    The inventory of mature fine tailings (MFT) produced by the oil sands extraction process continues to grow, and is considered as a long-term environmental liability. Large amounts of water are trapped in the MFT, and the tailings ponds present a threat to local wildlife and ecosystems. This PowerPoint presentation discussed a research project that is being conducted to identify conditions for producing stackable MFT deposits. The study is investigating various types and dosages of polymers and evaluating the degrees of MFT dilution and process configurations needed to maximize re-usable water recovery. Polymeric flocculants include AL-PAM and Magnafloc 1011. Settling tests have demonstrated that 50 ppm is the optimum dosage for both polymers when MFT is diluted to 5 wt percent solids, while 75 ppm of AL-PAM and 100 ppm of MF1011 are optimum dosages for MFT diluted to 10 wt percent solids. A novel supernatant filtration method was then used to produce filtration cakes and water. The study showed that the supernatant can be used to further dilute the MFTs. tabs., figs.

  14. Heavy Tail Behavior of Rainfall Extremes across Germany

    Science.gov (United States)

    Castellarin, A.; Kreibich, H.; Vorogushyn, S.; Merz, B.

    2017-12-01

    Distributions are termed heavy-tailed if extreme values are more likely than would be predicted by probability distributions that have exponential asymptotic behavior. Heavy-tail behavior often leads to surprise, because historical observations can be a poor guide for the future. Heavy-tail behavior seems to be widespread for hydro-meteorological extremes, such as extreme rainfall and flood events. To date there have been only vague hints to explain under which conditions these extremes show heavy-tail behavior. We use an observational data set consisting of 11 climate variables at 1440 stations across Germany. This homogenized, gap-free data set covers 110 years (1901-2010) at daily resolution. We estimate the upper tail behavior, including its uncertainty interval, of daily precipitation extremes for the 1,440 stations at the annual and seasonal time scales. Different tail indicators are tested, including the shape parameter of the Generalized Extreme Value distribution, the upper tail ratio and the obesity index. In a further step, we explore to which extent the tail behavior can be explained by geographical and climate factors. A large number of characteristics is derived, such as station elevation, degree of continentality, aridity, measures for quantifying the variability of humidity and wind velocity, or event-triggering large-scale atmospheric situation. The link between the upper tail behavior and these characteristics is investigated via data mining methods capable of detecting non-linear relationships in large data sets. This exceptionally rich observational data set, in terms of number of stations, length of time series and number of explaining variables, allows insights into the upper tail behavior which is rarely possible given the typical observational data sets available.

  15. Quasi-steady state aerodynamics of the cheetah tail.

    Science.gov (United States)

    Patel, Amir; Boje, Edward; Fisher, Callen; Louis, Leeann; Lane, Emily

    2016-08-15

    During high-speed pursuit of prey, the cheetah (Acinonyx jubatus) has been observed to swing its tail while manoeuvring (e.g. turning or braking) but the effect of these complex motions is not well understood. This study demonstrates the potential of the cheetah's long, furry tail to impart torques and forces on the body as a result of aerodynamic effects, in addition to the well-known inertial effects. The first-order aerodynamic forces on the tail are quantified through wind tunnel testing and it is observed that the fur nearly doubles the effective frontal area of the tail without much mass penalty. Simple dynamic models provide insight into manoeuvrability via simulation of pitch, roll and yaw tail motion primitives. The inertial and quasi-steady state aerodynamic effects of tail actuation are quantified and compared by calculating the angular impulse imparted onto the cheetah's body and its shown aerodynamic effects contribute to the tail's angular impulse, especially at the highest forward velocities. © 2016. Published by The Company of Biologists Ltd.

  16. The Sodium Tail of the Moon

    Science.gov (United States)

    Matta, M.; Smith, S.; Baumgardner, J.; Wilson, J.; Martinis, C.; Mendillo, M.

    2009-01-01

    During the few days centered about new Moon, the lunar surface is optically hidden from Earth-based observers. However, the Moon still offers an observable: an extended sodium tail. The lunar sodium tail is the escaping "hot" component of a coma-like exosphere of sodium generated by photon-stimulated desorption, solar wind sputtering and meteoroid impact. Neutral sodium atoms escaping lunar gravity experience solar radiation pressure that drives them into the anti-solar direction forming a comet-like tail. During new Moon time, the geometry of the Sun, Moon and Earth is such that the anti-sunward sodium flux is perturbed by the terrestrial gravitational field resulting in its focusing into a dense core that extends beyond the Earth. An all-sky camera situated at the El Leoncito Observatory (CASLEO) in Argentina has been successfully imaging this tail through a sodium filter at each lunation since April 2006. This paper reports on the results of the brightness of the lunar sodium tail spanning 31 lunations between April 2006 and September 2008. Brightness variability trends are compared with both sporadic and shower meteor activity, solar wind proton energy flux and solar near ultra violet (NUV) patterns for possible correlations. Results suggest minimal variability in the brightness of the observed lunar sodium tail, generally uncorrelated with any single source, yet consistent with a multi-year period of minimal solar activity and non-intense meteoric fluxes.

  17. Developmentally Regulated Post-translational Modification of Nucleoplasmin Controls Histone Sequestration and Deposition

    Directory of Open Access Journals (Sweden)

    Takashi Onikubo

    2015-03-01

    Full Text Available Nucleoplasmin (Npm is an abundant histone chaperone in vertebrate oocytes and embryos. During embryogenesis, regulation of Npm histone binding is critical for its function in storing and releasing maternal histones to establish and maintain the zygotic epigenome. Here, we demonstrate that Xenopus laevis Npm post-translational modifications (PTMs specific to the oocyte and egg promote either histone deposition or sequestration, respectively. Mass spectrometry and Npm phosphomimetic mutations used in chromatin assembly assays identified hyperphosphorylation on the N-terminal tail as a critical regulator for sequestration. C-terminal tail phosphorylation and PRMT5-catalyzed arginine methylation enhance nucleosome assembly by promoting histone interaction with the second acidic tract of Npm. Electron microscopy reconstructions of Npm and TTLL4 activity toward the C-terminal tail demonstrate that oocyte- and egg-specific PTMs cause Npm conformational changes. Our results reveal that PTMs regulate Npm chaperoning activity by modulating Npm conformation and Npm-histone interaction, leading to histone sequestration in the egg.

  18. Estimating contaminant discharge rates from stabilized uranium tailings embankments

    International Nuclear Information System (INIS)

    Weber, M.F.

    1986-01-01

    Estimates of contaminant discharge rates from stabilized uranium tailings embankments are essential in evaluating long-term impacts of tailings disposal on groundwater resources. Contaminant discharge rates are a function of water flux through tailings covers, the mass and distribution of tailings, and the concentrations of contaminants in percolating pore fluids. Simple calculations, laboratory and field testing, and analytical and numerical modeling may be used to estimate water flux through variably-saturated tailings under steady-state conditions, which develop after consolidation and dewatering have essentially ceased. Contaminant concentrations in water discharging from the tailings depend on tailings composition, leachability and solubility of contaminants, geochemical conditions within the embankment, tailings-water interactions, and flux of water through the embankment. These concentrations may be estimated based on maximum reported concentrations, pore water concentrations, extrapolations of column leaching data, or geochemical equilibria and reaction pathway modeling. Attempts to estimate contaminant discharge rates should begin with simple, conservative calculations and progress to more-complicated approaches, as necessary

  19. Tailings dams from the perspective of conventional dam engineering

    International Nuclear Information System (INIS)

    Szymanski, M.B.

    1999-01-01

    A guideline intended for conventional dams such as hydroelectric, water supply, flood control, or irrigation is used sometimes for evaluating the safety of a tailings dam. Differences between tailings dams and conventional dams are often substantial and, as such, should not be overlooked when applying the techniques or safety requirements of conventional dam engineering to tailings dams. Having a dam safety evaluation program developed specifically for tailings dams is essential, if only to reduce the chance of potential errors or omissions that might occur when relying on conventional dam engineering practice. This is not to deny the merits of using the Canadian Dam Safety Association Guidelines (CDSA) and similar conventional dam guidelines for evaluating the safety of tailings dams. Rather it is intended as a warning, and as a rationale underlying basic requirement of tailings dam emgineering: specific experience in tailings dams is essential when applying conventional dam engineering practice. A discussion is included that focuses on the more remarkable tailings dam safety practics. It is not addressed to a technical publications intended for such dams, or significantly different so that the use of conventional dam engineering practice would not be appropriate. The CDSA Guidelines were recently revised to include tailings dams. But incorporating tailings dams into the 1999 revision of the CDSA Guidelines is a first step only - further revision is necessary with respect to tailings dams. 11 refs., 2 tabs

  20. Collisional relaxation of electron tail distribution

    International Nuclear Information System (INIS)

    Yamagiwa, Mitsuru; Okamoto, Masao.

    1985-05-01

    Relaxation due to the Coulomb collisions of the electron velocity distribution function with a high energy tail is investigated in detail. In the course of the relaxation, a 'saddle' point can be created in velocity space owing to upsilon -3 dependence of the deflection rate and a positive slope or a 'dip' appears in the tail direction. The time evolution of the electron tail is studied analytically. A comparison is made with numerical results by using a Fokker-Planck code. Also discussed is the kinetic instability concerned with the positive slope during the relaxation. (author)

  1. Environmental impact of uranium mining and milling

    International Nuclear Information System (INIS)

    Dory, A.B.

    1981-08-01

    The author introduces the subject with an overview of the regulatory requirments and philosophy applied to uranium mines and mills. The special attention given to tailings management is highlighted, and a discussion of the basic environmental concerns is concluded with an itemizing of the main tasks facing the AECB. The extent of the environmental impact of uranium mining, milling and waste management is illustrated with specific details pertaining to mines in the Elliot Lake area. The author concludes that the impact on the ground and surface water system is not alarming, and the impact on air quality is not significant beyond a few hundred metres from the mining facilities. The publicly perceived impact is discussed, followed by a rationale for the continued licensing of new uranium mining operations complete with tailings management facilities

  2. Why are most EU pigs tail docked?

    DEFF Research Database (Denmark)

    D'eath, R.B.; Niemi, J.K.; Vosough Ahmadi, B.

    2016-01-01

    To limit tail biting incidence, most pig producers in Europe tail dock their piglets. This is despite EU Council Directive 2008/120/EC banning routine tail docking and allowing it only as a last resort. The paper aims to understand what it takes to fulfil the intentions of the Directive...... by examining economic results of four management and housing scenarios, and by discussing their consequences for animal welfare in the light of legal and ethical considerations. The four scenarios compared are: ‘Standard Docked’, a conventional housing scenario with tail docking meeting the recommendations...... for Danish production (0.7 m2/pig); ‘Standard Undocked’, which is the same as ‘Standard Docked’ but with no tail docking, ‘Efficient Undocked’ and ‘Enhanced Undocked’, which have increased solid floor area (0.9 and 1.0 m2/pig, respectively) provision of loose manipulable materials (100 and 200 g/straw per...

  3. Reconstruction of the 2015 Atacama Floods: Influence of Legacy Mining Deposits in the Salado River Mouth

    Science.gov (United States)

    Fuenzalida Callejas, M. J.; Contreras Vargas, M. T.; Escauriaza, C. R.

    2016-12-01

    In March 2015, the Salado watershed in the Atacama Desert was affected by unusual storms that unleashed floods never recorded before in northern Chile. Chañaral, an urban center located at the mouth of the Salado River, suffered the most catastrophic consequences on the population and infrastructure. Several natural and anthropic factors contributed to the magnitude and effects observed in this event. The total precipitation, of more than 80 mm in the upper section of the basin, produced a massive and rapid hyperconcentrated flow from the Andean foothills, which propagated along the channel with high velocities, depositing more than 2 m of mud in Chañaral. The dynamics of the flood in the city was also influenced by mine tailings deposited at the river mouth. The mining industry in this region during the previous century deposited approximately 200 million tons of mine tailings in the Chañaral Bay. The accumulation of this legacy mining deposits at the river mouth changed the local morphodynamics, which exacerbated the impacts of the flood. The objective of this work is to improve our understanding of the factors that affect the hydrodynamic of floods in hyper-arid regions. We perform numerical simulations using data collected in the field to reconstruct the event of March 2015 in Chañaral, integrating hydrological and hydrodynamic models to propagate the hydrograph in the city with high resolution. By using the reconstruction of the hydrograph and peak flow estimated by Wilcox et al., 2016, we simulate the flood using a two-dimensional model of the shallow-water equations, fully coupled with the sediment concentration (Contreras & Escauriaza, 2016). To identify the influence of the tailing deposits on the flow hydrodynamics, we use high-resolution data of the pre- and post-disaster topography. We compare the performance of different methodologies to assess the destructive power of the flood, considering also the influence of the sediment concentration in the

  4. Unique structural features facilitate lizard tail autotomy.

    Science.gov (United States)

    Sanggaard, Kristian W; Danielsen, Carl Chr; Wogensen, Lise; Vinding, Mads S; Rydtoft, Louise M; Mortensen, Martin B; Karring, Henrik; Nielsen, Niels Chr; Wang, Tobias; Thøgersen, Ida B; Enghild, Jan J

    2012-01-01

    Autotomy refers to the voluntary shedding of a body part; a renowned example is tail loss among lizards as a response to attempted predation. Although many aspects of lizard tail autotomy have been studied, the detailed morphology and mechanism remains unclear. In the present study, we showed that tail shedding by the Tokay gecko (Gekko gecko) and the associated extracellular matrix (ECM) rupture were independent of proteolysis. Instead, lizard caudal autotomy relied on biological adhesion facilitated by surface microstructures. Results based on bio-imaging techniques demonstrated that the tail of Gekko gecko was pre-severed at distinct sites and that its structural integrity depended on the adhesion between these segments.

  5. Basic description of tailings from Aitik focusing on mechanical behavior

    OpenAIRE

    Bhanbhro, Riaz; Knutsson, Roger; Rodriguez, Juan; Edeskär, Tommy; Knutsson, Sven

    2013-01-01

    Tailings are artificial granular materials that behave different as compared to natural soil of equal grain sizes. Tailings particle sizes, shapes, gradation and mechanical behavior may influence the performance of tailings dams. Hence it is essential to understand the tailings materials in depth. This article describes present studies being carried out on Aitik tailings. Basic tailings characteristics including specific gravity, phase relationships, particle sizes, particle shapes and direct...

  6. A new procedure for deep sea mining tailings disposal

    OpenAIRE

    Ma, W.; Schott, D.L.; Lodewijks, G.

    2017-01-01

    Deep sea mining tailings disposal is a new environmental challenge related to water pollution, mineral crust waste handling, and ocean biology. The objective of this paper is to propose a new tailings disposal procedure for the deep sea mining industry. Through comparisons of the tailings disposal methods which exist in on-land mining and the coastal mining fields, a new tailings disposal procedure, i.e., the submarine–backfill–dam–reuse (SBDR) tailings disposal procedure, is proposed. It com...

  7. Metal mobilization under alkaline conditions in ash-covered tailings.

    Science.gov (United States)

    Lu, Jinmei; Alakangas, Lena; Wanhainen, Christina

    2014-06-15

    The aim of this study was to determine element mobilization and accumulation in mill tailings under alkaline conditions. The tailings were covered with 50 cm of fly ash, and above a sludge layer. The tailings were geochemically and mineralogically investigated. Sulfides, such as pyrrhotite, sphalerite and galena along with gangue minerals such as dolomite, calcite, micas, chlorite, epidote, Mn-pyroxene and rhodonite were identified in the unoxidized tailings. The dissolution of the fly ash layer resulted in a high pH (close to 12) in the underlying tailings. This, together with the presence of organic matter, increased the weathering of the tailings and mobilization of elements in the uppermost 47 cm of the tailings. All primary minerals were depleted, except quartz and feldspar which were covered by blurry secondary carbonates. Sulfide-associated elements such as Cd, Fe, Pb, S and Zn and silicate-associated elements such as Fe, Mg and Mn were released from the depletion zone and accumulated deeper down in the tailings where the pH decreased to circum-neutral. Sequential extraction suggests that Cd, Cu, Fe, Pb, S and Zn were retained deeper down in the tailings and were mainly associated with the sulfide phase. Calcium, Cr, K and Ni released from the ash layer were accumulated in the uppermost depletion zone of the tailings. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. The radiological impacts of uranium mill tailings - a review with special emphasis on the tailings at Ranstad in Sweden

    International Nuclear Information System (INIS)

    Snihs, J.O.; Agnedal, P.O.

    1978-07-01

    The environmental impact of uranium mill tailings can be expressed in collective dose commitment and corresponding detriment per MWsub(e).Y energy produced by the uranium which corresponds to the amount of waste of interest. The methods of dose commitment calculations are discussed and it is suggested for the purpose of estimation of the detriment to limit the commitment to 10,000 years. The external radiation from the tailings is easily reduced by covering but in case of a future settlement on the tailings the collective dose commitment will be some hundreds to thousands of manrad/MWsub(e).Y depending on the quality of the uranium ore. The dispersion of dust from uncovered tailings is mainly a local problem and the collective dose commitment for critical tissues in the lung will be less than a manrad/MWsub(e).Y. In the long run the cover may be lost and the resultant collective dose commitment for the critical tissues in the lung will be a few tens of manrad/MWsub(e).Y depending on the quality of the tailings. The effects of global dispersion of the material in the tailings are also discussed

  9. Ilmenite Mineral's Recovery from Beach Sand Tailings

    International Nuclear Information System (INIS)

    Mulaba-Bafubiandi, Antoine F.; Mukendi-Ngalula, David; Waanders, Frans B.

    2002-01-01

    The mineral ilmenite is the major source of rutile for industrial use and is of interest to paint and fertiliser industries. Enormous unutilised tailing dams lie on the eastern coast of the South Africa. Although covered by a simulation of the original indigenous vegetation, these tailings are still ilmenite bearing and of economic value. Tailings emanating from beach sand mineral slimes dams of the Kwazulu-Natal area (South Africa) have been processed. Screening, flotation, spiral concentration and magnetic separation methods were used either separately or successively. The present work sheds light on alternative routes for the extraction of the ilmenite, from these tailings. It moreover points out the usefulness of the Moessbauer spectroscopy in the mineral processing product monitoring. Tailings from the beach sands were used in the present study after the economic industrial minerals zirconia, ilmenite and rutile had been extracted in previous mining operations. About 61% natural ilmenite recovery was observed in the flotation concentrate of a Humphrey Spiral concentrate while a 62% recovery of hematite was found in the flotation tailings. The combination of screening, spiral concentration and magnetic separation, and flotation yielded a product with the highest ilmenite and hematite concentration being 71% and 19%, respectively. A natural ilmenite mineral, containing 87% ilmenite and 13% hematite, could be produced and extracted from the tailings of the flotation process, collected subsequently to the spiral concentration and the initial screening.

  10. Chaperone role for proteins p618 and p892 in the extracellular tail development of Acidianus two-tailed virus

    DEFF Research Database (Denmark)

    Scheele, Urte; Erdmann, Susanne; Ungewickell, Ernst J.

    2011-01-01

    The crenarchaeal Acidianus two-tailed virus (ATV) undergoes a remarkable morphological development, extracellularly and independently of host cells, by growing long tails at each end of a spindle-shaped virus particle. Initial work suggested that an intermediate filament-like protein, p800...... the interactions observed between the different protein and DNA components and to explain their possible structural and functional roles in extracellular tail development....

  11. Asbestos pollution in an inactive mine: determination of asbestos fibers in the deposit tailings and water.

    Science.gov (United States)

    Koumantakis, Emmanouil; Kalliopi, Anastasiadou; Dimitrios, Kalderis; Gidarakos, Evangelos

    2009-08-15

    An inactive asbestos mine in Northern Greece, known as MABE, had been operational for 18 years, showing an annual chrysotile production of approximately 100,000 tons. It is estimated that a total of 68 million tons of the mineral serpentine were excavated from the mine, of which 881,000 tons of chrysotile asbestos were produced. The mine deposits are located very near to the river Aliakmonas. The water of the river is extensively used as drinking water, as well as for irrigation. This study estimated the amount of asbestos currently present in the deposits, to at least 1.33 million tons. This is a 10-fold increase since the start of mine operation in 1982. Water samples obtained throughout the river had high chrysotile concentrations, in most cases far exceeding EPA's standard value (7 x 10(6)f/l). Therefore, the mine and the deposits urgently require remediation works, such as removal of large contaminated objects from the mine buildings and re-vegetation of the deposit areas, in order to reduce the asbestos levels in the river water.

  12. Fat-tailed distributions data, diagnostics and dependence

    CERN Document Server

    Cooke, Roger M; Misiewicz, Jolanta

    2014-01-01

    This title is written for the numerate nonspecialist, and hopes to serve three purposes. First it gathers mathematical material from diverse but related fields of order statistics, records, extreme value theory, majorization, regular variation and subexponentiality. All of these are relevant for understanding fat tails, but they are not, to our knowledge, brought together in a single source for the target readership. Proofs that give insight are included, but for most fussy calculations the reader is referred to the excellent sources referenced in the text. Multivariate extremes are not treated. This allows us to present material spread over hundreds of pages in specialist texts in twenty pages. Chapter 5 develops new material on heavy tail diagnostics and gives more mathematical detail. Since variances and covariances may not exist for heavy tailed joint distributions, Chapter 6 reviews dependence concepts for certain classes of heavy tailed joint distributions, with a view to regressing heavy tailed variabl...

  13. Overview by Pioneer observations of the distant geomagnetic tail

    Energy Technology Data Exchange (ETDEWEB)

    Villante, U [L' Aquila Univ. (Italy). Istituto de Astrofisica

    1977-03-01

    Pioneer 7 and Pioneer 8 spacecraft provided the only direct observations of the geomagnetic tail at geocentric distances as large as 1000 Rsub(e) and 500 Rsub(e) respectively. The presence of a low density plasma flow in the region of expected tail and the intermittent and short duration character of the tail encounters suggested in the past a distant tail structure remarkably different from its near-earth and cislunar shape. However the recent discovery of the plasma mantle allows interpretation of the Pioneer observations in terms of a distant tail that possibly is still preserving most of its near-earth characteristics. In particular, the region of tail encounters and the magnitude and direction of the observed magnetic field might be consistent with a cylindrical tail with a modestly increased cross-section. Neutral sheet observations also appear to be consistent with the most recent bidimensional tail models. Finally, as in the cislunar region, the double peaked proton energy spectra can be interpreted in terms of a partial intermingling of plasma sheet and plasma mantle populations.

  14. Vertical Tail Buffeting Alleviation Using Piezoelectric Actuators-Some Results of the Actively Controlled Response of Buffet-Affected Tails (ACROBAT) Program

    Science.gov (United States)

    Moses, Robert W.

    1997-01-01

    Buffet is an aeroelastic phenomenon associated with high performance aircraft especially those with twin vertical tails. In particular, for the F/A-18 aircraft at high angles of attack, vortices emanating from wing/fuselage leading edge extensions burst, immersing the vertical tails in their wake. The resulting buffet loads on the vertical tails are a concern from fatigue and inspection points of view. Recently, a 1/6-scale F-18 wind-tunnel model was tested in the Transonic Dynamics Tunnel at the NASA Langley Research Center as part of the Actively Controlled Response Of Buffet Affected Tails (ACROBAT) Program to assess the use of active controls in reducing vertical tail buffeting. The starboard vertical tail was equipped with an active rudder and the port vertical tail was equipped with piezoelectric actuators. The tunnel conditions were atmospheric air at Mach 0.10. By using single-input-single-output control laws at gains well below the physical limits of the actuators, the power spectral density of the root strains at the frequency of the first bending mode of the vertical tail was reduced by as much as 60 percent up to angles of attack of 37 degrees. Root mean square (RMS) values of root strain were reduced by as much as 19 percent. The results herein illustrate that buffet alleviation of vertical tails can be accomplished using simple active control of the rudder or piezoelectric actuators. In fact, as demonstrated herein, a fixed gain single input single output control law that commands piezoelectric actuators may be active throughout the high angle-of-attack maneuver without requiring any changes during the maneuver. Future tests are mentioned for accentuating the international interest in this area of research.

  15. Seepage water balance of the mixed tailings site IAA Dresden-Coschuetz/Gittersee by means of the two-dimensional model BOWAHALD

    International Nuclear Information System (INIS)

    Helling, C.; Dunger, V.

    1998-01-01

    Uranium mill tailings were deposited in a section of the Kaitzbach valley which was closed by tow dams. The Kaitzbach creek was cased in the area. After the uranium ore processing was finish the dump was used as a municipal waste deposit. The water balance of the IAA Dresden-Coschuetz/Gittersee was only estimated in former works. In this case a modeling of the water balance is very useful in regard to a process orientated quantification of the contaminant transport within the dump as well as into the underground. Simplified and rough estimating methods such as the runoff coefficient concept or rating curves are less suited because of the complexity of the processes. That's why we tried to get a runoff and seepage water balance by means of a two-dimensional water balance model for waste heaps called BOWAHALD. The tailings site IAA Dresden-Coschuetz/Gittersee was divited into several hydrotopes (areas with similar hydrological characteristics). Different exposition and slopes as well as different soils and vegetation were taken into account. The parameter verification is possible due to comparison with available data such hydrochemical and isotopic analysis of seepage water and groundwater. (orig.)

  16. UTAP, U Tailings Assessment Program

    International Nuclear Information System (INIS)

    Holmes, Ron

    1998-01-01

    1 - Description of program or function: UTAP carries out probabilistic analyses of the behaviour and environmental effects of uranium mill tailings, following close-out of milling operations. The models have been designed to allow predictions to be made for distances up to 50 kilometers in all directions from the tailings area. The models include features which include the ability to incorporate different receptors and site characteristics and to deal with input parameters which vary with time. 2 - Method of solution: UTAP is composed of a number of modules. These may be classified as either component or control modules. Component modules (or models) are the programs directly concerned with the simulation of a uranium tailings physical system; that is the computer implementation of the mathematical models representing the uranium tailings pile and surrounding environment. Control modules provide the infrastructure for probabilistic analysis using the component modules. These functions include probabilistic sampling of input parameters such as constant, normal, log-normal, uniform, log-uniform, triangular, Weibull, Beta, arbitrary and correlated. The sampling method used is straight Monte Carlo. The radionuclides modelled are: natural uranium, total thorium, radium-226, radon-222 and lead-210. The pH of the reference uranium tailings site and a chained river-lake system are also modelled. For the afore- mentioned radionuclides the following pathways of dose to the receptors modelled: water consumption, fish consumption, radon inhalation, dust inhalation, vegetable consumption, animal produce consumption and ground-shine. 3 - Restrictions on the complexity of the problem: The maximum number of steps through time allowed is 300

  17. Unique structural features facilitate lizard tail autotomy.

    Directory of Open Access Journals (Sweden)

    Kristian W Sanggaard

    Full Text Available Autotomy refers to the voluntary shedding of a body part; a renowned example is tail loss among lizards as a response to attempted predation. Although many aspects of lizard tail autotomy have been studied, the detailed morphology and mechanism remains unclear. In the present study, we showed that tail shedding by the Tokay gecko (Gekko gecko and the associated extracellular matrix (ECM rupture were independent of proteolysis. Instead, lizard caudal autotomy relied on biological adhesion facilitated by surface microstructures. Results based on bio-imaging techniques demonstrated that the tail of Gekko gecko was pre-severed at distinct sites and that its structural integrity depended on the adhesion between these segments.

  18. Ecological restoration alters microbial communities in mine tailings profiles.

    Science.gov (United States)

    Li, Yang; Jia, Zhongjun; Sun, Qingye; Zhan, Jing; Yang, Yang; Wang, Dan

    2016-04-29

    Ecological restoration of mine tailings have impact on soil physiochemical properties and microbial communities. The surface soil has been a primary concern in the past decades, however it remains poorly understood about the adaptive response of microbial communities along the profile during ecological restoration of the tailings. In this study, microbial communities along a 60-cm profile were investigated in a mine tailing pond during ecological restoration of the bare waste tailings (BW) with two vegetated soils of Imperata cylindrica (IC) and Chrysopogon zizanioides (CZ) plants. Revegetation of both IC and CZ could retard soil degradation of mine tailing by stimulation of soil pH at 0-30 cm soils and altered the bacterial communities at 0-20 cm depths of the mine tailings. Significant differences existed in the relative abundance of the phyla Alphaproteobacteria, Deltaproteobacteria, Acidobacteria, Firmicutes and Nitrospira. Slight difference of bacterial communities were found at 30-60 cm depths of mine tailings. Abundance and activity analysis of nifH genes also explained the elevated soil nitrogen contents at the surface 0-20 cm of the vegetated soils. These results suggest that microbial succession occurred primarily at surface tailings and vegetation of pioneering plants might have promoted ecological restoration of mine tailings.

  19. Ecological restoration alters microbial communities in mine tailings profiles

    Science.gov (United States)

    Li, Yang; Jia, Zhongjun; Sun, Qingye; Zhan, Jing; Yang, Yang; Wang, Dan

    2016-04-01

    Ecological restoration of mine tailings have impact on soil physiochemical properties and microbial communities. The surface soil has been a primary concern in the past decades, however it remains poorly understood about the adaptive response of microbial communities along the profile during ecological restoration of the tailings. In this study, microbial communities along a 60-cm profile were investigated in a mine tailing pond during ecological restoration of the bare waste tailings (BW) with two vegetated soils of Imperata cylindrica (IC) and Chrysopogon zizanioides (CZ) plants. Revegetation of both IC and CZ could retard soil degradation of mine tailing by stimulation of soil pH at 0-30 cm soils and altered the bacterial communities at 0-20 cm depths of the mine tailings. Significant differences existed in the relative abundance of the phyla Alphaproteobacteria, Deltaproteobacteria, Acidobacteria, Firmicutes and Nitrospira. Slight difference of bacterial communities were found at 30-60 cm depths of mine tailings. Abundance and activity analysis of nifH genes also explained the elevated soil nitrogen contents at the surface 0-20 cm of the vegetated soils. These results suggest that microbial succession occurred primarily at surface tailings and vegetation of pioneering plants might have promoted ecological restoration of mine tailings.

  20. Integrating miRNA and mRNA Expression Profiling Uncovers miRNAs Underlying Fat Deposition in Sheep

    Directory of Open Access Journals (Sweden)

    Guangxian Zhou

    2017-01-01

    Full Text Available MicroRNAs (miRNAs are endogenous, noncoding RNAs that regulate various biological processes including adipogenesis and fat metabolism. Here, we adopted a deep sequencing approach to determine the identity and abundance of miRNAs involved in fat deposition in adipose tissues from fat-tailed (Kazakhstan sheep, KS and thin-tailed (Tibetan sheep, TS sheep breeds. By comparing HiSeq data of these two breeds, 539 miRNAs were shared in both breeds, whereas 179 and 97 miRNAs were uniquely expressed in KS and TS, respectively. We also identified 35 miRNAs that are considered to be putative novel miRNAs. The integration of miRNA-mRNA analysis revealed that miRNA-associated targets were mainly involved in the gene ontology (GO biological processes concerning cellular process and metabolic process, and miRNAs play critical roles in fat deposition through their ability to regulate fundamental pathways. These pathways included the MAPK signaling pathway, FoxO and Wnt signaling pathway, and focal adhesion. Taken together, our results define miRNA expression signatures that may contribute to fat deposition and lipid metabolism in sheep.

  1. A proactive approach to sustainable management of mine tailings

    Science.gov (United States)

    Edraki, Mansour; Baumgartl, Thomas

    2015-04-01

    The reactive strategies to manage mine tailings i.e. containment of slurries of tailings in tailings storage facilities (TSF's) and remediation of tailings solids or tailings seepage water after the decommissioning of those facilities, can be technically inefficient to eliminate environmental risks (e.g. prevent dispersion of contaminants and catastrophic dam wall failures), pose a long term economic burden for companies, governments and society after mine closure, and often fail to meet community expectations. Most preventive environmental management practices promote proactive integrated approaches to waste management whereby the source of environmental issues are identified to help make a more informed decisions. They often use life cycle assessment to find the "hot spots" of environmental burdens. This kind of approach is often based on generic data and has rarely been used for tailings. Besides, life cycle assessments are less useful for designing operations or simulating changes in the process and consequent environmental outcomes. It is evident that an integrated approach for tailings research linked to better processing options is needed. A literature review revealed that there are only few examples of integrated approaches. The aim of this project is to develop new tailings management models by streamlining orebody characterization, process optimization and rehabilitation. The approach is based on continuous fingerprinting of geochemical processes from orebody to tailings storage facility, and benchmark the success of such proactive initiatives by evidence of no impacts and no future projected impacts on receiving environments. We present an approach for developing such a framework and preliminary results from a case study where combined grinding and flotation models developed using geometallurgical data from the orebody were constructed to predict the properties of tailings produced under various processing scenarios. The modelling scenarios based on the

  2. Effects of tail docking and docking length on neuroanatomical changes in healed tail tips of pigs

    DEFF Research Database (Denmark)

    Herskin, M S; Thodberg, K; Jensen, Henrik Elvang

    2015-01-01

    % (n=19); or leaving 25% (n=11) of the tail length on the pigs. The piglets were docked between day 2 and 4 after birth using a gas-heated apparatus, and were kept under conventional conditions until slaughter at 22 weeks of age, where tails were removed and examined macroscopically and histologically...

  3. Processes for extracting radium from uranium mill tailings

    International Nuclear Information System (INIS)

    Nirdosh, I.; Baird, M.H.; Muthuswami, S.V.

    1987-01-01

    This patent describes a process for the extraction of radium from uranium mill tailings solids including the steps of contacting the tailings with a liquid leaching agent, leaching the tailings therewith and subsequently separating the leachate liquid and the leached solids. The improvement described here is wherein the leaching agent comprises: (a) a complexing agent in an amount of from 2 to 10 times the stoichiometric amount needed to complex the metal ions to be removed thereby from the tailings; and (b) a reducing agent reducing the hydrolysable ions of the metal ions to be removed to their lower oxidation states, the reduction agent being present in an amount from 2 to 10 times the stoichiometric amount needed for reducing the hydrolysable metals present in the tailings

  4. Fat-tailed risk about climate change and climate policy

    International Nuclear Information System (INIS)

    Hwang, In Chang; Tol, Richard S.J.; Hofkes, Marjan W.

    2016-01-01

    This paper investigates the role of emissions control in welfare maximization under fat-tailed risk about climate change. We provide a classification of fat tails and discuss the effect of fat-tailed risk on climate policy. One of the main findings is that emissions control may prevent the “strong” tail-effect from arising, at least under some conditions such as bounded temperature increases, low risk aversion, low damage costs, and bounded utility function. More specifically, the fat-tailed risk with respect to a climate parameter does not necessarily lead to an unbounded carbon tax. In this case, the basic principle of cost-benefit analysis maintains its applicability. - Highlights: • A fat tail is classified and the tail effect on climate policy is discussed. • The optimal carbon tax is not necessarily unbounded. • The basic principle of cost-benefit analysis maintains its applicability. • This is a numerical confirmation of the recent theoretical research.

  5. Impact of flocculation on flotation tailing's hydro-cycloning properties

    Directory of Open Access Journals (Sweden)

    Knežević Dinko N.

    2014-01-01

    Full Text Available Research results of hydro-cycloning of flocculated and non-flocculated flotation tailing from the lead and zinc open pit mine 'Suplja stijena', Sula - Montenegro have been shown in this paper. Reason for this research was finding conditions in order to separate fraction that is suitable for embankment erection. Flotation tailings has been tested in the very state that it goes out from the flotation process and tailings which is flocculated by anionic flocculant. The object was to determine the impact of flocculation on properties of hydro-cycloning products and disposal process. In hydro-cycloning process greater underflow mass is being separated with non-flocculated tailing. Values of geomechanical parameters are significantly different, especially hydro-cyclone's underflow. All geomechanical parameters of hydro-cyclone's underflow are suitable for erecting embankment which shall be made from non-flocculated tailing. Underflow drainage of non-flocculated tailing is faster while overflow drainage is slower and problematic with both tailings.

  6. Long-term ecological behaviour of abandoned uranium mill tailings. 1

    International Nuclear Information System (INIS)

    Kalin, M.

    1983-03-01

    Inactive uranium mill tailings were surveyed in the Province of Ontario to describe their surface characteristics, identify naturally invading biota, and determine essential chemical and physical parameters associated with the tailings. Inactive tailings sites can have wet areas, tailings completely covered with water, and dry areas. In the wet areas of most sites, wetland vegetation stands were found which were dominated by species of cattails (Typhaceae), along with some species of rushes (Juncaceae) and sedges (Cyperceae). Dry areas of the tailings exhibited a variety of surface features which are often a reflection of different amelioration efforts. Most of the indigenous species of vascular plants identified on dry areas of the tailings occurred only sporadically. Invading plants found on most sites were the tree species, trembling aspen (Populus tremuloides) and paper birch (Betula papyrifera). Elemental concentration and some physical characteristics of the tailings collected from a depth of 0-20 cm were determined. Uptake of heavy metals and radionuclides were evaluated in trees found in the dry areas and in cattails (Typha latifolia) in the wetland areas. Water bodies on tailings and surface water leaving the tailings, before and after treatment, were characterized in this survey. Aquatic bryophytes have invaded some water bodies on the tailings, and acid tolerant algae were evident in most of the water associated with the tailings. Ecological processes occurring on inactive uranium mill tailings which were identified in this survey are essential in evaluating the long-term fate of these waste sites

  7. A qualitative evaluation of long-term processes governing the behaviour of uranium mill tailings placed in deep lakes

    International Nuclear Information System (INIS)

    1982-03-01

    The emplacement of uranium mill tailings in deep lakes may provide an acceptable method of tailings disposal at certain sites in Canada. Disposal in a depositional environment typical of deep lakes appears to offer greater prospects for long-term stability than present methods of land-based management. From the regulatory point of view, it is necessary to know which factors should be taken into account in assessing the acceptability of such an approach. This report examines the environmental variables governing the behaviour of radionuclides and trace elements in the groundwater systems, lake water, and finally in the biosphere over the short and long term. Physical, chemical and biological factors are each considered. Conclusions are presented in terms of points for and against disposal in deep lakes. This report summarizes the data and conclusions presented in an annex volume

  8. Leachability of radioactive constituents from uranium mine tailings

    International Nuclear Information System (INIS)

    Constable, T.W.

    1987-04-01

    A series of long-term studies were conducted both to examine the leachability of major constituents (acidity, TDS) and radioisotopes from uranium mining/milling tailings and settling pond sludges, and to assess the effect of two treatment methods (solidification and vegetation) on leachate characteristics. Four bench-scale experiments were conducted to examine the leachability of: 1) old tailings and those containing a large portion of (Ba,Ra)SO 4 sludges; 2) untreated and solidified (Ba,Ra)SO 4 sludges located at the bottom of settling ponds; 3) new tailings that had been vegetated or solidified; and 4) new tailings subject to varying flow rates. A fifth study was conducted to examine the microbiology of Experiments 2 and 3. In addition, the lysimeter solids remaining in the old tailings at the end of Experiment 1 were characterized through chemical and radionuclide analyses and Scanning Electron Microscope-X-ray Emission and Mossbauer Spectroscopy techniques. This report provides an extensive database of temporal variations in leachate characteristics under both normal and accelerated water application rates. It also presents hypotheses of possible leaching mechanisms in the wastes that could explain the observed data, and conceptual model of tailings leaching processes which integrates the results of all the tailings experiments

  9. How We Tend To Overestimate Powerlaw Tail Exponents

    OpenAIRE

    Nassim N. Taleb

    2012-01-01

    In the presence of a layer of metaprobabilities (from uncertainty concerning the parameters), the asymptotic tail exponent corresponds to the lowest possible tail exponent regardless of its probability. The problem explains "Black Swan" effects, i.e., why measurements tend to chronically underestimate tail contributions, rather than merely deliver imprecise but unbiased estimates.

  10. Electrodialytic remediation of copper mine tailings

    DEFF Research Database (Denmark)

    Hansen, Henrik K.; Rojo, A.; Ottpsen, Lisbeth M.

    2005-01-01

    electrodialytic remediation experiments on copper mine tailings. The results show that electric current could remove copper from watery tailing if the potential gradient was higher than 2V/cm during 21 days. With addition of sulphuric acid, the process was enhanced because the pH decreased to around 4...

  11. Moth tails divert bat attack: evolution of acoustic deflection.

    Science.gov (United States)

    Barber, Jesse R; Leavell, Brian C; Keener, Adam L; Breinholt, Jesse W; Chadwell, Brad A; McClure, Christopher J W; Hill, Geena M; Kawahara, Akito Y

    2015-03-03

    Adaptations to divert the attacks of visually guided predators have evolved repeatedly in animals. Using high-speed infrared videography, we show that luna moths (Actias luna) generate an acoustic diversion with spinning hindwing tails to deflect echolocating bat attacks away from their body and toward these nonessential appendages. We pit luna moths against big brown bats (Eptesicus fuscus) and demonstrate a survival advantage of ∼ 47% for moths with tails versus those that had their tails removed. The benefit of hindwing tails is equivalent to the advantage conferred to moths by bat-detecting ears. Moth tails lured bat attacks to these wing regions during 55% of interactions between bats and intact luna moths. We analyzed flight kinematics of moths with and without hindwing tails and suggest that tails have a minimal role in flight performance. Using a robust phylogeny, we find that long spatulate tails have independently evolved four times in saturniid moths, further supporting the selective advantage of this anti-bat strategy. Diversionary tactics are perhaps more common than appreciated in predator-prey interactions. Our finding suggests that focusing on the sensory ecologies of key predators will reveal such countermeasures in prey.

  12. Characterization and monitoring of transverse beam tails

    International Nuclear Information System (INIS)

    Seeman, J.T.; Decker, F.J.; Hsu, I.; Young, C.

    1991-05-01

    Low emittance electron beams accelerated to high energy in a linac experience transverse effects (wakefield, filamentation, optics) which produce non-Gaussian projected transverse beam distributions. Characterizations of the beam shapes are difficult because the shapes are asymmetric and change with betatron phase. In this note several methods to describe beam distributions are discussed including an accelerator physics model of these tails. The uses of these characterizations in monitoring the beam emittances in the SLC are described in this paper. First, two dimensional distributions from profile monitor screens are reviewed showing correlated tails. Second, a fitting technique for non-Gaussian one dimensional distributions is used to extract the core from the tail areas. Finally, a model for tail propagation in the linac is given. 3 refs., 6 figs

  13. International experience in tailings pond remediation

    Energy Technology Data Exchange (ETDEWEB)

    MacG. Robertson, A. [Robertson GeoConsultants Ltd., Vancouver (Canada)

    2001-07-01

    Tailings pond remediation is required primarily on mine closure. While mining is an ancient industry, requirement for mine facility remediation is a comparatively new development. Requirement for remediation has come about partly as a result of mans awareness of the environmental impacts of mining and his desire to minimize this, partly, as a result of the ever-increasing scale and production rates of tailings generation and the resulting increased environmental impacts and safety risks. The paper starts with a review of the evolution of mans intolerance of environmental impacts from tailings production and the assignment of liability to remediate such impacts. Many of the tailings ponds currently undergoing remediation were designed and constructed using methods and technology that would be considered inappropriate for new impoundments being designed and developed today. The paper reviews the history of tailings impoundment design and construction practice and the resulting inherent deficiencies that must be remediated. Current practices and future trends in tailings pond remediation are reviewed. The evolution of regulatory requirements is not only in terms of technical and safety criteria, but also in terms of financial and political risk. Perhaps the most substantive driver of risk management is today the requirement for corporate governance at mining company board level and oversight of new project development in the underdeveloped countries by the large financial institutions responsible for funding projects. Embarrassment in the public eye and punishment in the stock markets for poor environmental and safety performance is driving the need for efficient and effective risk management of potential impacts and the remediation to avoid these. A basis for practical risk management is described. (orig.)

  14. International experience in tailings pond remediation

    International Nuclear Information System (INIS)

    Robertson, A.MacG.

    2001-01-01

    Tailings pond remediation is required primarily on mine closure. While mining is an ancient industry, requirement for mine facility remediation is a comparatively new development. Requirement for remediation has come about partly as a result of mans awareness of the environmental impacts of mining and his desire to minimize this, partly, as a result of the ever-increasing scale and production rates of tailings generation and the resulting increased environmental impacts and safety risks. The paper starts with a review of the evolution of mans intolerance of environmental impacts from tailings production and the assignment of liability to remediate such impacts. Many of the tailings ponds currently undergoing remediation were designed and constructed using methods and technology that would be considered inappropriate for new impoundments being designed and developed today. The paper reviews the history of tailings impoundment design and construction practice and the resulting inherent deficiencies that must be remediated. Current practices and future trends in tailings pond remediation are reviewed. The evolution of regulatory requirements is not only in terms of technical and safety criteria, but also in terms of financial and political risk. Perhaps the most substantive driver of risk management is today the requirement for corporate governance at mining company board level and oversight of new project development in the underdeveloped countries by the large financial institutions responsible for funding projects. Embarrassment in the public eye and punishment in the stock markets for poor environmental and safety performance is driving the need for efficient and effective risk management of potential impacts and the remediation to avoid these. A basis for practical risk management is described. (orig.)

  15. Flexible histone tails in a new mesoscopic oligonucleosome model.

    Science.gov (United States)

    Arya, Gaurav; Zhang, Qing; Schlick, Tamar

    2006-07-01

    We describe a new mesoscopic model of oligonucleosomes that incorporates flexible histone tails. The nucleosome cores are modeled using the discrete surface-charge optimization model, which treats the nucleosome as an electrostatic surface represented by hundreds of point charges; the linker DNAs are treated using a discrete elastic chain model; and the histone tails are modeled using a bead/chain hydrodynamic approach as chains of connected beads where each bead represents five protein residues. Appropriate charges and force fields are assigned to each histone chain so as to reproduce the electrostatic potential, structure, and dynamics of the corresponding atomistic histone tails at different salt conditions. The dynamics of resulting oligonucleosomes at different sizes and varying salt concentrations are simulated by Brownian dynamics with complete hydrodynamic interactions. The analyses demonstrate that the new mesoscopic model reproduces experimental results better than its predecessors, which modeled histone tails as rigid entities. In particular, our model with flexible histone tails: correctly accounts for salt-dependent conformational changes in the histone tails; yields the experimentally obtained values of histone-tail mediated core/core attraction energies; and considers the partial shielding of electrostatic repulsion between DNA linkers as a result of the spatial distribution of histone tails. These effects are crucial for regulating chromatin structure but are absent or improperly treated in models with rigid histone tails. The development of this model of oligonucleosomes thus opens new avenues for studying the role of histone tails and their variants in mediating gene expression through modulation of chromatin structure.

  16. Assessment of the underground disposal of tailings

    Energy Technology Data Exchange (ETDEWEB)

    Hutt, N M [Morwijk Enterprises Ltd., (Canada); Morin, K A [Normar Enterprises, (Canada)

    1995-06-01

    The Atomic Energy Control Board (AECB) of Canada is facing the issue of long-term disposal of uranium tailings. One option that has not been examined in sufficient detail for the AECB is the retrieval of tailings from surface impoundments and subsequent placement of those tailings in underground workings of mines. This report is structured like a catalogue of facts and information, with each paragraph presenting some concept, concern, theory, or case study involving the retrieval or placement of tailings. All relevant information, findings, interpretations, conclusions, and recommendations gathered during the course of this study are included. The Table of Contents illustrates the striking number of relevant topics and acts like a flowchart or checklist to ensure that an underground-disposal submission by a mining company has addressed relevant topics. This report explains in detail the implications of disturbing surface-impounded tailings for the purpose of placing only some of the volume underground. The cumulative environmental, safety, and monetary liabilities of such a partial scheme can be discouraging in some cases. (author). 244 refs., 47 tabs., 17 figs.

  17. Assessment of the underground disposal of tailings

    International Nuclear Information System (INIS)

    Hutt, N.M.; Morin, K.A.

    1995-06-01

    The Atomic Energy Control Board (AECB) of Canada is facing the issue of long-term disposal of uranium tailings. One option that has not been examined in sufficient detail for the AECB is the retrieval of tailings from surface impoundments and subsequent placement of those tailings in underground workings of mines. This report is structured like a catalogue of facts and information, with each paragraph presenting some concept, concern, theory, or case study involving the retrieval or placement of tailings. All relevant information, findings, interpretations, conclusions, and recommendations gathered during the course of this study are included. The Table of Contents illustrates the striking number of relevant topics and acts like a flowchart or checklist to ensure that an underground-disposal submission by a mining company has addressed relevant topics. This report explains in detail the implications of disturbing surface-impounded tailings for the purpose of placing only some of the volume underground. The cumulative environmental, safety, and monetary liabilities of such a partial scheme can be discouraging in some cases. (author). 244 refs., 47 tabs., 17 figs

  18. Geochemical Characterization of Copper Tailings after Legume Revegetation

    Directory of Open Access Journals (Sweden)

    Justine Perry T. Domingo

    2014-12-01

    Full Text Available Knowledge on the geochemistry of mine tailings is important in understanding the challenges in establishing vegetation cover on tailings dumps and mined out areas. In this study, the mineralogy and trace element composition of copper tailings were examined. Two legume species, Calopogonium mucunoides and Centrosema molle, were utilized to investigate the possible effects of these plants in the geochemical development of mine tailings into soil-like material. The initial mineralogical and chemical analysis of the tailings samples indicated poor conditions for plant growth—minimal levels of major nutrients and organic matter as well as elevated copper concentrations. Despite these conditions, the two legume species exhibited good growth rates. Both legumes have likewise signif icantly reduced heavy metal concentrations in the tailings, indicating the possibility of metal hyperaccumulation in the plant tissue. The mineral composition has been retained even after revegetation; nevertheless, breakdown of primary minerals and subsequent formation of clay minerals were detected. These results provide insights on the transformation of toxic materials into habitable substrates for sustained plant growth.

  19. Soil pollution by oxidation of tailings from toxic spill of a pyrite mine

    International Nuclear Information System (INIS)

    Simon, M.; Martin, F.; Ortiz, I.; Garcia, I.; Fernandez, J.; Fernandez, E.; Dorronsoro, C.; Aguilar, J.

    2001-01-01

    On the 25th April 1998, toxic water and tailings from a pyrite mine of Aznalcollar (southern Spain) spilled into the Agrio and Guadiamar River Basin affecting some 40 km 2 . In five sectors throughout the basin, we monitored the physical and chemical properties of the tailings as well as the degree of pollution in the soils on four different sampling dates: 5 May, 20 May, 4 June and 22 July 1998. The characteristics of the tailings deposited on the soils are shown to be related to distance from the spill. The oxidation rate of the tailings and the solubilization of the pollutant elements were more pronounced in the middle and lower sectors of the basin, where the particle size was finer, the sulfur content higher and the bulk density less. The increases in water-soluble sulfates, Zn, Cd and Cu were very rapid (the highest values being reached 25 days after the spill) and intense (reaching 45% of the total Cu, 65% of the total Zn and Cd). Meanwhile, the increases in water-soluble As, Bi, Sb, Pb and Tl were far lower (ranging between 0.002% of the total Tl and 2.5% of the total As) and less rapid in the case of As, Bi and Pb (the highest values for these elements being reached 40 days after the spill). These soluble elements infiltrated the soils with the rainwater, swiftly augmenting the soil pollution. Twenty-five days after the spill, when the rainfall ranged between 45 and 63 mm, the first 10-cm of the soils in the middle and lower sectors of the basin exceeded the maximum concentration permitted for agricultural soils in Zn, Cu and Tl. At 40 days after the spill, when the rainfall ranged between 60 and 89 mm, all the soils reached or exceeded the maximum permitted concentrations for As and Tl. Nevertheless, the pollutants tended to concentrate in the first 10 cm of the soils without seriously contaminating either the subsoil or the groundwaters. Consequently, a rapid removal of the tailings and the ploughing of the first 25-30 cm of the soils would be urgent

  20. Effect of a Metal Deactivator Fuel Additive on Fuel Deposition in Fuel Atomizers at High Temperature

    Science.gov (United States)

    1992-08-01

    ARMY NATICK RD&E CENTER DEVELOPMENT AND ENGINEERING CTR ATTN: SATNC-U ATUN : SATBE-F I NATICK MA 01760-5020 SATBE-FL 10 SATBE-BT 2 DIRECTOR SATBE-TQ 1...SFT (MR MAKRIS) I WASHINGTON DC 20330 SAALC/LDPE (MR ELLIOT) 1 KELLY AIR FORCE BASE TX 78241 CDR US AIR FORCE WRIGHT AERO LAB CDR ATUN : POSF (MR

  1. Grouting of uranium mill tailings piles

    International Nuclear Information System (INIS)

    Boegly, W.J. Jr.; Tamura, T.; Williams, J.D.

    1984-03-01

    A program of remedial action was initiated for a number of inactive uranium mill tailings piles. These piles result from mining and processing of uranium ores to meet the nation's defense and nuclear power needs and represent a potential hazard to health and the environment. Possible remedial actions include the application of covers to reduce radon emissions and airborne transport of the tailings, liners to prevent groundwater contamination by leachates from the piles, physical or chemical stabilization of the tailings, or moving the piles to remote locations. Conventional installation of liners would require excavation of the piles to emplace the liner; however, utilization of grouting techniques, such as those used in civil engineering to stabilize soils, might be a potential method of producing a liner without excavation. Laboratory studies on groutability of uranium mill tailings were conducted using samples from three abandoned piles and employing a number of particulate and chemical grouts. These studies indicate that it is possible to alter the permeability of the tailings from ambient values of 10 -3 cm/s to values approaching 10 -7 cm/s using silicate grouts and to 10 -8 cm/s using acrylamide and acrylate grouts. An evaluation of grouting techniques, equipment required, and costs associated with grouting were also conducted and are presented. 10 references, 1 table

  2. Sirenomelia apus with vestigial tail.

    Science.gov (United States)

    Parikh, Tushar B; Nanavati, Ruchi N; Udani, Rekha H

    2005-04-01

    Sirenomelia is an exceptionally rare congenital malformation characterized by complete or near complete fusion of lower limbs. A newborn with clinical features of sirenomelia including fused lower limbs in medial position, absent fibula, anal atresia, complete absence of urogenital system (bilateral renal agenesis, absent ureters, urinary bladder, absent internal and external genitalia), a single umbilical artery and a vestigial tail is reported. Association of vestigial tail with sirenomelia is not described in the literature.

  3. Research on the characterization and conditioning of uranium mill tailings. III. Summary of uranium mill tailings conditioning research and implications regarding remedial actions

    International Nuclear Information System (INIS)

    Dreesen, D.R.; Cokal, E.J.; Thode, E.F.; Williams, J.M.

    1983-06-01

    This report summarizes the findings of research on uranium mill tailings conditioning technology development performed for the Department of Energy's (DOE) Uranium Mill Tailings Remedial Action Project (UMTRAP). Hazards and risks posed by tailings piles are discussed in relation to the goal of conditioning the tailings to reduce these hazards. The results of our efforts regarding characterization of tailings, removal of radionuclides, mineral recovery, thermal stabilization, and engineering/economic analysis of conditioning are presented. The implications of these results for remedial action plans are discussed and conclusions regarding the applicability of these technologies are also presented

  4. BIOMECHANICS. Why the seahorse tail is square.

    Science.gov (United States)

    Porter, Michael M; Adriaens, Dominique; Hatton, Ross L; Meyers, Marc A; McKittrick, Joanna

    2015-07-03

    Whereas the predominant shapes of most animal tails are cylindrical, seahorse tails are square prisms. Seahorses use their tails as flexible grasping appendages, in spite of a rigid bony armor that fully encases their bodies. We explore the mechanics of two three-dimensional-printed models that mimic either the natural (square prism) or hypothetical (cylindrical) architecture of a seahorse tail to uncover whether or not the square geometry provides any functional advantages. Our results show that the square prism is more resilient when crushed and provides a mechanism for preserving articulatory organization upon extensive bending and twisting, as compared with its cylindrical counterpart. Thus, the square architecture is better than the circular one in the context of two integrated functions: grasping ability and crushing resistance. Copyright © 2015, American Association for the Advancement of Science.

  5. Micropore Structure of Cement-Stabilized Gold Mine Tailings

    Directory of Open Access Journals (Sweden)

    Joon Kyu Lee

    2018-03-01

    Full Text Available Mine tailings have often to be stabilized by mixing them with cementing agents. In this study, the pore structure of gold tailings stabilized with Portland cement was evaluated by means of mercury intrusion porosimetry. The investigation was conducted on samples prepared with different fractions of tailings and cement as well as on samples activated with elevated temperature curing and chemical (CaCl2 addition. It was observed that all mixed samples exhibit a mono-modal pore size distribution, indicating that the cement-stabilized tailings are characterized by a single-porosity structure. The results also showed that the higher fraction of tailings and cement leads to a dense and finer pore structure. The total porosity of mixture samples decreases with increasing curing temperature and CaCl2 concentration due to the acceleration of hydration reaction.

  6. Dewatering Behaviour of Fine Oil Sands Tailings : An Experimental Study

    NARCIS (Netherlands)

    Yao, Y.

    2016-01-01

    Oil sands tailings are a warm aqueous suspension of sand, silt, clay, residual bitumen and naphtha. The tailings are hydraulically transported and stored in tailing ponds where they segregate, with the sand settling from suspension forming beaches and the remaining tailings flowing to the middle of

  7. A Glimpse of the genomic diversity of haloarchaeal tailed viruses

    Directory of Open Access Journals (Sweden)

    Ana eSencilo

    2014-03-01

    Full Text Available Tailed viruses are the most common isolates infecting prokaryotic hosts residing hypersaline environments. Archaeal tailed viruses represent only a small portion of all characterized tailed viruses of prokaryotes. But even this small dataset revealed that archaeal tailed viruses have many similarities to their counterparts infecting bacteria, the bacteriophages. Shared functional homologues and similar genome organizations suggested that all microbial tailed viruses have common virion architectural and assembly principles. Recent structural studies have provided evidence justifying this thereby grouping archaeal and bacterial tailed viruses into a single lineage. Currently there are 17 haloarchaeal tailed viruses with entirely sequenced genomes. Nine viruses have at least one close relative among the 17 viruses and, according to the similarities, can be divided into three groups. Two other viruses share some homologues and therefore are distantly related, whereas the rest of the viruses are rather divergent (or singletons. Comparative genomics analysis of these viruses offers a glimpse into the genetic diversity and structure of haloarchaeal tailed virus communities.

  8. Structural Conservation of the Myoviridae Phage Tail Sheath Protein Fold

    Energy Technology Data Exchange (ETDEWEB)

    Aksyuk, Anastasia A.; Kurochkina, Lidia P.; Fokine, Andrei; Forouhar, Farhad; Mesyanzhinov, Vadim V.; Tong, Liang; Rossmann, Michael G. (SOIBC); (Purdue); (Columbia)

    2012-02-21

    Bacteriophage phiKZ is a giant phage that infects Pseudomonas aeruginosa, a human pathogen. The phiKZ virion consists of a 1450 {angstrom} diameter icosahedral head and a 2000 {angstrom}-long contractile tail. The structure of the whole virus was previously reported, showing that its tail organization in the extended state is similar to the well-studied Myovirus bacteriophage T4 tail. The crystal structure of a tail sheath protein fragment of phiKZ was determined to 2.4 {angstrom} resolution. Furthermore, crystal structures of two prophage tail sheath proteins were determined to 1.9 and 3.3 {angstrom} resolution. Despite low sequence identity between these proteins, all of these structures have a similar fold. The crystal structure of the phiKZ tail sheath protein has been fitted into cryo-electron-microscopy reconstructions of the extended tail sheath and of a polysheath. The structural rearrangement of the phiKZ tail sheath contraction was found to be similar to that of phage T4.

  9. Polymer aids for settling and filtration of oil sands tailings

    Energy Technology Data Exchange (ETDEWEB)

    Wang, X. [Alberta Univ., Edmonton, AB (Canada). Dept. of Chemical and Materials Engineering; Energy Resources Conservation Board, Calgary, AB (Canada). Oil Sands Section; Xu, Z.; Masliyah, J.H. [Alberta Univ., Edmonton, AB (Canada). Dept. of Chemical and Materials Engineering

    2008-07-01

    Oil sand tailings are segregated into coarse and fine tailings. High volumes of toxic fluids and tailings are created in the process. Tailings ponds are an environmental risk with high operating and maintenance costs. Current commercial technologies uses chemical additions to create recycled water and composite tailings (CT). Researchers are now investigating centrifuged and dry mature fine tailings (MFT). Filtration processes with flocculants are used to separate the tailings into warm recycle water and dried cakes that can be used in reclamation processes. Studies are being conducted to find a polymer than can effectively flocculate and filter whole oil sands tailings. The filtration procedure uses pressure to produce released water. Polymers include magnafloc and Al-PAM polymer concentrations are used in slurry masses. Tests have been conducted to determine the settling rates of the polymers. The tests showed that Al-PAM filtered the tailings effectively. Paraffinic froth treatment tests have also been conducted to determine settling rates. A cake produced with froth treatment tailings of Al-PAM 400 ppm had a water content 42.5 wt per cent. The tests showed that while Magnafloc 1011 is a good settling aid, but a poor filtration addition. Al-PAM aided in both the flocculation and filtration processes. Higher Al-PAM dosages are needed for froth treatment tailings processes. It was concluded that dry cakes are produced with the addition of Al-PAM. tabs., figs.

  10. The problem of abandoned uranium tailings in northern Saskatchewan

    International Nuclear Information System (INIS)

    Swanson, S.; Abouguendia, Z.

    1981-11-01

    Two Saskatchewan tailings sites, Lorado and Gunnar, covering approximately 89 ha., were abandoned in the early 1960s leaving untreated tailings in lakes and depressions. This report reviews the literature on environmental conditions in abandoned uranium tailings and available managmenet and mitigation options, and identifies research requirements essential for proper treatment of these two sites. The recommended management plan includes isolation of the exposed tailings area from surface waters, stabilization of the exposed tailings surfaces, diversion of runoff around tailings, treatment of overflow water before release, and implementation of an environmental monitoring program. Revegetation appears to be a promising stabilization measure, but research is needed into propagation methods of appropriate native species. Studies of the existing geological and hydrological conditions at both sites, detailed characterization of the wastes, field testing of different surface treatment methods, and nutrient cycling investigations are also needed

  11. Asymmetric Extreme Tails and Prospective Utility of Momentum Returns

    NARCIS (Netherlands)

    Stork, P.A.; Gregory-Allen, R.; Lu, H.

    2012-01-01

    We use extreme value theory to analyse the tails of a momentum strategy's return distribution. The asymmetry between the fat left tail and thin right tail strongly reduces a momentum strategy's prospective utility levels. © 2012 Elsevier B.V.

  12. Measurement of radon flux and tailings parameters for quantifying the source term due to radon exhalation from U tailings pile at Jaduguda

    International Nuclear Information System (INIS)

    Sahoo, B.K.; Mayya, Y.S.; Sapra, B.K.; Gaware, J.J.; Khuswaha, H.S.

    2010-01-01

    Full text: The exposures from radon ( 222 Rn) and its decay products have been received considerable attention in the world community because of their adverse health effect. There are various natural and man-made sources of radon present in our environment. Among the man-made sources, the U tailings (waste product from U mining and milling facility) may be considered an important one because it contains significant amount of 226 Ra activity after the U extraction from the ore bodies. These tailings (slurry form) are being impounded into a repository site nearby the facility called 'Tailings Pile' (TP). Significant amount of radon emission takes place from this area by the process of emanation and exhalation. Hence, a study was taken up to quantify the source term arising due to radon emission from uranium tailings pile at Jaduguda in Jharkhand state. In-situ experiments were conducted at 40 locations of the uranium tailings pile in three seasons namely summer, rainy and winter to measure the radon fluxes. The measurements were carried out by deploying a cylindrical chamber, attached to a continuous radon monitor, on the surface of the tailings pile. The dimension of the chamber was selected by using a recently developed two dimensional theory of soil chamber, so that radon concentration growth will be in exponential fashion and the data generated within 2-3 hours of deployment period will be sufficient for accurately deriving the actual radon flux. After the data collection, the fluxes were derived by fitting an exponential growth function to the plot of radon concentration with time. The fluxes were also predicted by diffusion theory using the measured tailings parameters such as 226 Ra content, radon emanation factor, porosity, temperature and moisture. An excellent matching between the predicted and measured fluxes was observed. The validity of diffusion theory in the matrix of U tailings pile provides an alternate method for back-calculating the tailings

  13. Limits theorems for tail processes with applications tointermediate quantile estimation

    NARCIS (Netherlands)

    Einmahl, J.H.J.

    1992-01-01

    A description of the weak and strong limiting behaviour of weighted uniform tail empirical and tail quantile processes is given. The results for the tail quantile process are applied to obtain weak and strong functional limit theorems for a weighted non-uniform tail-quantile-type process based on a

  14. Uranium speciation in the environment: study of opals from Nopal I (Mexico) and mill tailings from Gunnar (Canada)

    International Nuclear Information System (INIS)

    Othmane, G.

    2012-01-01

    Understanding the processes of uranium migration and sequestration is an important issue for the prediction of radionuclide retardation in the vicinity of uranium mine tailings sites or for the safety assessment of potential high-level nuclear waste repositories. Uranium speciation, controlled by biotic and abiotic factors, represents a key parameter for the control of uranium transfer in the environment. This study firstly deals with uranium speciation in opals from the Nopal I uranium deposit (Mexico). Microscopic observations of opals at the nano-scale revealed the occurrence of vorlanite, cubic CaUO 4 . This was the first time this rare calcium uranate has been found displaying a cubic morphology, in agreement with its crystal structure. Nopal I opals have been further investigated through time-resolved laser fluorescence spectroscopy. The opals spectra and their comparison with those of experimentally produced standards indicate occurrence of mono- or polymeric uranyl complexes (associated or not with calcium or phosphate) sorbed onto internal surface of opal around pH 7-8. Finally, the speciation of uranium was studied in mill tailings from Gunnar (Canada). In the first tailings site, uranium primarily occurs as monomeric, inner-sphere uranyl complexes sharing edges with Fe(O,OH) 6 octahedral sites of iron-oxy-hydroxides and chlorite. Our results suggested that U(VI) co-precipitates with iron (oxy-hydr)oxides predominate in the second tailings sites. Therefore uranium mobility in Gunnar is governed by sorption/desorption and dissolution/(co)precipitation processes. (author)

  15. Functional morphology of the aardvark tail.

    Science.gov (United States)

    Endo, H; Mori, K; Koyabu, D; Kawada, S; Komiya, T; Itou, T; Koie, H; Kitagawa, M; Sakai, T

    2013-04-01

    The musculoskeletal system of the aardvark (Orycteropus afer) tail was morphologically examined in two adult specimens. The tail musculature comprised three muscular groups, viz. a dorsal sacrocaudal system that consisted of the irregularly oriented Musculus sacrocaudalis dorsalis medialis and M. sacrocaudalis dorsalis lateralis, a lateral inter-vertebral connecting system, and a ventral sacrocaudal system characterized by the thick M. sacrocaudalis ventralis lateralis and M. sacrocaudalis ventralis medialis. Both the dorsal and ventral systems possessed large tendon groups that strengthened the tail structure. Computed tomography (CT) examination showed the presence of large but homogeneous cartilaginous inter-vertebral discs, whereas V-shaped bones were situated at the ventral aspect of the caudal vertebrae at the level of the inter-vertebral discs. CT visualization of the tendons and V-shaped bones in various tail positions suggested that these structures contribute to the tunnel digging action by bearing the trunk weight and lending force when the aardvark are displacing the soil by means of the forelimbs. © 2012 Blackwell Verlag GmbH.

  16. Experiments on a Tail-wheel Shimmy

    Science.gov (United States)

    Harling, R; Dietz, O

    1954-01-01

    Model tests on the "running belt" and tests with a full-scale tail wheel were made on a rotating drum as well as on a runway in order to investigate the causes of the undesirable shimmy phenomena frequently occurring on airplane tail wheels, and the means of avoiding them. The small model (scale 1:10) permitted simulation of the mass, moments of inertia, and fuselage stiffness of the airplane and determination of their influence on the shimmy, whereas by means of the larger model with pneumatic tires (scale 1:2) more accurate investigations were made on the tail wheel itself. The results of drum and road tests show good agreement with one another and with model values. Detailed investigations were made regarding the dependence of the shimmy tendency on trail, rolling speed, load, size of tires, ground friction,and inclination of the swivel axis; furthermore, regarding the influence of devices with restoring effect on the tail wheel, and the friction damping required for prevention of shimmy. Finally observations from slow-motion pictures are reported and conclusions drawn concerning the influence of tire deformation.

  17. Uranium tailings in the public eye

    International Nuclear Information System (INIS)

    Lyon, B.

    1976-01-01

    The ORNL field team visits to Grand Junction, Colorado, and to other sources of uranium mill tailings, are described. The radioactive hazards of these tailings, which are principally due to Th, Ra, Rn, and radon daughters, are discussed briefly. Government actions which were taken as a result of public concern are listed. The ORNL Health Physics Division mobile laboratory van and its use in assessing the tailings piles at Salt Lake City and elsewhere are described. The highest γ-ray background found was 155 mRem/y, with levels being as high as 1750 mRem/y near points of public access to piles. Some possible solutions to the problem are discussed

  18. A hyper-robust sauropodomorph dinosaur ilium from the Upper Triassic-Lower Jurassic Elliot Formation of South Africa: Implications for the functional diversity of basal Sauropodomorpha

    Science.gov (United States)

    McPhee, Blair W.; Choiniere, Jonah N.

    2016-11-01

    It has generally been held that the locomotory habits of sauropodomorph dinosaurs moved in a relatively linear evolutionary progression from bipedal through "semi-bipedal" to the fully quadrupedal gait of Sauropoda. However, there is now a growing appreciation of the range of locomotory strategies practiced amongst contemporaneous taxa of the latest Triassic and earliest Jurassic. Here we present on the anatomy of a hyper-robust basal sauropodomorph ilium from the Late Triassic-Early Jurassic Elliot Formation of South Africa. This element, in addition to highlighting the unexpected range of bauplan diversity throughout basal Sauropodomorpha, also has implications for our understanding of the relevance of "robusticity" to sauropodomorph evolution beyond generalized limb scaling relationships. Possibly representing a unique form of hindlimb stabilization during phases of bipedal locomotion, the autapomorphic morphology of this newly rediscovered ilium provides additional insight into the myriad ways in which basal Sauropodomorpha managed the inherited behavioural and biomechanical challenges of increasing body-size, hyper-herbivory, and a forelimb primarily adapted for use in a bipedal context.

  19. Top Incomes, Heavy Tails, and Rank-Size Regressions

    Directory of Open Access Journals (Sweden)

    Christian Schluter

    2018-03-01

    Full Text Available In economics, rank-size regressions provide popular estimators of tail exponents of heavy-tailed distributions. We discuss the properties of this approach when the tail of the distribution is regularly varying rather than strictly Pareto. The estimator then over-estimates the true value in the leading parametric income models (so the upper income tail is less heavy than estimated, which leads to test size distortions and undermines inference. For practical work, we propose a sensitivity analysis based on regression diagnostics in order to assess the likely impact of the distortion. The methods are illustrated using data on top incomes in the UK.

  20. Predicting the long term stabilisation of uranium mill tailings

    International Nuclear Information System (INIS)

    Trojacek, J.

    2004-01-01

    The long-term stabilization and remediation of uranium mill tailings ponds is an important task for DIAMO. After uranium mining was stopped, DIAMO has to remediate more then 400 ha of tailings ponds at three locations. It is currently planned to cover the surface with low permeability materials with a slope of approx. 3% to protect the interior of the disposal facility from infiltrating rainwater. This entails to cover the free surface of these ponds with several hundred thousand tons of inert material. As a result of this load, the porewater from the tailings is expelled and the body of the impounded materials consolidates. Consolidation of tailings proceeds irregularly, depending on the internal structure of the tailings layers and on the progress of loading. The surface needs to be recontoured for a long time into the future. The topic of the DIAMO project is to predict and optimise the final surface contour of the tailings pond body, and to determine the time schedule and locations for recontouring work. The K1 tailings pond in Dolni Rozinka (Southern Moravia) is a typical example for such task. The average thickness of the tailings layer is around 25 m and the average porewater contents varies from 25 up to 40%. In the years 1998-99 a PHARE pilot project was undertaken that aimed to predict the quantity and quality of drainage and infiltration waters as a function of time. A new investigation programme (field, laboratory and modelling) has been implemented. The range of material properties and distribution of types of tailings was established. Orientation calculations of the tailings consolidation were made for fine slime zone. The results have shown that significant subsidence of the surface is to be expected after loading with inert material for the construction of an interim cover. (author)

  1. Activity, tail loss, growth and survivorship of male Psammodromus algirus

    OpenAIRE

    Salvador Milla, Alfredo; Veiga, José Pablo

    2005-01-01

    Males with autotomized tail were sighted more often and moved longer distances than males with complete tail. There were no significant differences in survival between the two groups. The increase of snout-vent lenght at emergence the following year was significantly lower for males with autotomized tail than for males with complete tail.

  2. Elemental characterization of Tummalapalle uranium mill tailing

    International Nuclear Information System (INIS)

    Patra, A.C.; Sahoo, S.K.; Thakur, V.K.; Dubey, J.S.; Jha, S.K.; Tripathi, R.M.; Sharma, D.B.

    2018-01-01

    Elements are present in environmental matrices at varying concentrations. Their levels may increase due to anthropogenic activities like transportation, industrial activities, agriculture, urbanization and human activities. Trace elements can be classified as potentially toxic (eg. cadmium, arsenic, mercury, lead, nickel), probably essential (eg. cobalt, vanadium) and essential (eg. iron, zinc, copper, selenium, manganese). Due to the expansion of the Indian Nuclear Power Programme, new uranium mining sites are coming up. Mining and milling produce large quantities of low active mill tailings contained in engineered Tailings Ponds. The tailings are amenable for interaction with the geochemical forces and can act as potential sources of contamination. Thus it is necessary to ascertain the concentrations of elements that are present therein. In this paper we aim to characterize the uranium tailings generated from Tummalapalle uranium mining facility in Kadappa district, Andhra Pradesh, India

  3. Application of dry stackable tailings technologies : providing the base for reclamation

    Energy Technology Data Exchange (ETDEWEB)

    Mikula, R.J. [Natural Resources Canada, Devon, AB (Canada). CANMET Energy Technology Centre

    2010-07-01

    The tailings containment structures are some of the largest man made features on the planet. This presentation demonstrated that dry stackable tailings technology may reduce the volume of the accumulated fluid fine tailings. Dry stackable tailings can contribute to boreal forest reclamation and reduce water requirement from the Athabasca River. Much of the water used for the production of each barrel of bitumen is recycled. The water is tied up in the pore spaces of the mineral sand, silt, and clay component which forms the mature fine tailings (MFT) that are contained behind large dykes. Syncrude and Suncor have used a wide variety of technologies to create a dry stackable tailings from this fluid fine tailings substrate. The availability of dry stackable tailings will open options for reclamation strategies that end with the original wetlands or boreal forest. Some of the tailings management options that would lead to a dry stackable tailings naturally also significantly decrease the barrels of water lost with each barrel of bitumen production. These options were discussed along with an analysis of their impact on recycle and pore water quality and quantity. There is an opportunity to remove residual bitumen during the transfer of fluid fine tailings to recover water and create dry stackable tailings. If this bitumen removal is extensive enough, it might be possible to use the dry stackable tailings directly as a reclamation material. tabs., figs.

  4. Asphalt emulsion sealing of uranium mill tailings. 1979 annual report

    International Nuclear Information System (INIS)

    Hartley, J.N.; Koehmstedt, P.L.; Esterl, D.J.; Freeman, H.D.

    1980-06-01

    Uranium mill tailings are a source of low-level radiation and radioactive materials that may be released into the environment. Stabilization or disposal of these tailings in a safe and environmentally sound way is necessary to minimize radon exhalation and other radioactive releases. One of the most promising concepts for stabilizing uranium tailings is being investigated at the Pacific Northwest Laboratory: the use of asphalt emulsion to contain radon and other potentially hazardous materials in uranium tailings. Results of these studies indicate that radon flux from uranium tailings can be reduced by greater than 99% by covering the tailings with an asphalt emulsion that is poured on or sprayed on (3.0 to 7.0 mm thick), or mixed with some of the tailings and compacted to form an admixture seal (2.5 to 15.2 cm) containing 18 wt % residual asphalt

  5. Leachability of metals from gold tailings by rainwater: an ...

    African Journals Online (AJOL)

    Mine leachates from gold tailings impoundments usually contain elevated concentrations of metals and sulphates that impact negatively on water quality. This study was aimed at assessing the leachability of such metals from tailings by rainwater. Oxidised and unoxidised tailings were leached experimentally and through ...

  6. Development in helicopter tail boom strake applications in the US

    Science.gov (United States)

    Wilson, John C.; Kelley, Henry L.; Donahue, Cynthia C.; Yenni, Kenneth R.

    1988-01-01

    The use of a strake or spoiler on a helicopter tail boom to beneficially change helicopter tail boom air loads was suggested in the United States in 1975. The anticipated benefits were a change of tail boom loads to reduce required tail rotor thrust and power and improve directional control. High tail boom air loads experienced by the YAH-64 and described in 1978 led to a wind tunnel investigation of the usefullness of strakes in altering such loads on the AH-64, UH-60, and UH-1 helicopters. The wind tunnel tests of 2-D cross sections of the tail boom of each demonstrated that a strake or strakes would be effective. Several limited test programs with the U.S. Army's OH-58A, AH-64, and UH-60A were conducted which showed the effects of strakes were modest for those helicopters. The most recent flight test program, with a Bell 204B, disclosed that for the 204B the tail boom strake or strakes would provide more than a modest improvement in directional control and reduction in tail rotor power.

  7. The environmental impacts of one of the largest tailing dam failures worldwide.

    Science.gov (United States)

    Hatje, Vanessa; Pedreira, Rodrigo M A; de Rezende, Carlos Eduardo; Schettini, Carlos Augusto França; de Souza, Gabriel Cotrim; Marin, Danieli Canaver; Hackspacher, Peter Christian

    2017-09-06

    The impacts of the SAMARCO iron tailing spill along more than 650 km, between the dam and the plume of the Doce River in the Atlantic, were assessed by the determination of toxic metals. The tailing spill caused a substantial increase in suspended sediment loads (up to 33,000 mg L -1 ), in addition to large depositions of waste along the Doce basin. The highest estimated transport of dissolved metals was observed for Fe (58.8 μg s -1 ), Ba (37.9 μg s -1 ) and Al (25.0 μg s -1 ). Sediments reached the highest enrichment factors (EFs) for Hg (4,234), Co (133), Fe (43), and Ni (16), whereas As (55), Ba (64), Cr (16), Cu (17), Mn (41), Pb (38) and Zn (82) highest EFs were observed for suspended particulate matter (SPM). Iron, As, Hg, Mn exceeded sediment quality guidelines. Therefore, the risk of occurrence of adverse effects is highly possible, not only due to the dam failure, but also due to the Fe mining and the artisan Au mining. Heavy rain episodes will likely cause enhanced erosion, remobilization, and transport of contaminated particles, sustaining high inputs of SPM and metals for the years to come and threatening the ecosystem services.

  8. Tail-robust scheduling using Limited Processor Sharing.

    NARCIS (Netherlands)

    Nair, J.K.; Wierman, A.; Zwart, A.P.

    2010-01-01

    From a rare events perspective, scheduling disciplines that work well under light (exponential) tailed workload distributions do not perform well under heavy (power) tailed workload distributions, and vice versa, leading to fundamental problems in designing schedulers that are robust to

  9. The radiological impacts of uranium mill tailings - A review with special emphasis on the tailings at Ranstad in Sweden

    International Nuclear Information System (INIS)

    Snihs, J.O.

    1978-01-01

    The environmental impact of uranium mill talings can be expressed in collective dose commitment and corresponding detriment per MWe.y energy produced by the uranium which corresponds to the amount of waste interest, The methods of dose commitment calculations are discussed and it is suggested for the purpose of estimation of the detriment to limit the commitment to 10,000 years. The external radiation from the tailings is easily reduced by covering but in case of a future settlement on the tailings the collective dose commitment will be some hundreds to thousands of manrad/MWe.y depending on the quality of the uranium ore. The dispersion of dust from uncovered tailings is mainly a local problem and the collective dose commitment for critical tissues in the lung will be less than a manrad/MWe.y. In the long run the cover may be lost and the resultant collective dose commitment for the critical tissues in the lung will be a few tens of manrad/MWe.y depending on the quality of the tailings. The effects of global dispersion of the material in the tailings are also discussed

  10. Conversion of a tailing impoundment to a freshwater reservoir, the Eagle Park Reservoir project, Climax Mine, Colorado

    Energy Technology Data Exchange (ETDEWEB)

    Romig, B.R.; Cupp, J.L.; Ford, R.C.

    1999-07-01

    The Climax Molybdenum Mine, located near Leadville, Colorado, is the site of a lengthy mining history spanning more than 80 years. In the 1960's, extraction of molybdenum from oxide ore located adjacent to the massive molybdenite sulfide deposit resulted in the construction of an earthen core dam to impound fine-grained oxide tailing in the Eagle River Valley. Through recognized value of water storage and reclamation opportunities, a tailing removal project was initiated in 1993 to convert the impoundment facilities to a post-mining beneficial land use of developed water resources. An evaluation of the effect residual materials and lake dynamics would have on in-stream water quality was performed. Eagle Park Reservoir stands as a model for future reclamation efforts that involve water delivery to highly sensitive receiving waters. This paper provides a case study on project development, the evolution of water quality assessment, and the regulatory framework that contributed to this project's success.

  11. Evaluation of inactive uranium mill tailings sites for liner requirements: Characterization and interaction of tailings, soil, and liner materials

    International Nuclear Information System (INIS)

    Relyea, J.F.; Martin, W.J.

    1982-01-01

    This paper summarizes the results of laboratory experiments using soils from Clive, Utah and tailings samples from three inactive uranium processing sites. The results are to be used to predict contaminant behavior for comparison with the regulatory criteria to decide whether a liner is needed. The interactions of leachates with soils and liner material were studied using both batch and column methods. It is determined that batch leaching tests are suitable for screening a large number of tailings samples for relative contaminant concentrations between samples but not for determining contaminant concentrations and release rates in tailings leachate. The results of column leaching tests on samples of tailings from inactive sites indicate that contaminant concentrations are highest in initial leachate from the columns and that concentrations decrease by an order of magnitude or more after one pore volume

  12. A new procedure for deep sea mining tailings disposal

    NARCIS (Netherlands)

    Ma, W.; Schott, D.L.; Lodewijks, G.

    2017-01-01

    Deep sea mining tailings disposal is a new environmental challenge related to water pollution, mineral crust waste handling, and ocean biology. The objective of this paper is to propose a new tailings disposal procedure for the deep sea mining industry. Through comparisons of the tailings disposal

  13. Effect of sucralose and biostimulant on pre-and postharvest of blueberries (Vaccinium corymbosum L. cv. Elliot under organic and conventional production systems

    Directory of Open Access Journals (Sweden)

    Nelson Eduardo loyola lópez

    2016-04-01

    Full Text Available Blueberries (Vaccinium corymbosum L. cv. Elliot from organic and conventional sources were subjected to either a pre-harvest application with an organic biostimulant or a post-harvest coverage with sucralose. Fruits were assessed in terms of firmness, dry matter, ascorbic acid, soluble solids, sensory attributes and color, during storage at 0 °C and RH of 90%, for a period of 21 days. Each trial with three treatments: T0correspondingto the control, T1to an application of biostimulant,22 days before harvest, and T2 to a post-harvest coverage with sucralose. Fruits were evaluated in sensory aspect, with the participation of thirteen panelists, on day fifteen after being harvested and stored. Evaluations of both maturity and quality parameters were performed on days 1,7, 14and 21post-harvest.Pre-harvest treatment with the organic biostimulant showed a higher variation in dry matter and soluble solids, but these variations are not significant. The group with a coverage of Sucralose showed a significant increase in fruit firmness. The best sensory evaluation, was given by the panelists to the organic farming. Fruit measurements, such as color, ascorbic acid and colorimetry showed no significant differences in the results.

  14. The Aznalcollar (Spain) tailings pond failure of 1998 and the ecological disaster of Guadiamar river: causes, effects and lessons

    International Nuclear Information System (INIS)

    Ayala-Carcedo, F. J.

    2004-01-01

    On 1998 a large tailings pond confined by a rock fill dyke in the Aznalcollar metallic mine near Sevilla, at the SW of Spain, failed with a big impact on public opinion due to potential environmental Impact on Donana National Park,a key natural space for birds migration between Europea and Africa. The accident is placed in a comparative way with others in the world, the causes of failure, its dynamics and the spill are analysed and also the actual ecological impacts related to the tailings and acid waters scattered by the Agrio and Guadiamar rivers. The lessons for future design and location of these type of deposits and water dams are also presented. The accident very quick, was caused by shear failure of the foundation formation, a miocene over consolidated marly clay, known as Guadalquivir blue marl, through a vertical point and a bedding plane, as a result of a progressive failure process under high pore pressure. Dynamic liquefaction of tailings due to sudden vertical movement towards the void created by the initial movement was a key factor to increase the outwards movement of the dyke, broken by the movement, and the tailings spill. The double dyke failure (main dyke and internal one) produced a tailings spill with solid and liquid flow. The dynamics of these flows is presented and also the combination of factors driving to failure. the problem posed by the successive human institutional failures, a necessary cause driving to no consideration of the possibility of the progressive failure in these formations, known from 1964, is also analysed. (Author) 67 refs

  15. Long-term stabilization of uranium mill tailings

    International Nuclear Information System (INIS)

    Voorhees, L.D.; Sale, M.J.; Webb, J.W.; Mulholland, P.J.

    1983-01-01

    The primary hazard associated with uranium mill tailings is exposure to a radioactive gas, radon-222, the concentration of which has been correlated with the occurrence of lung cancer. Previous studies on radon attenuation conclude that the placement of earthen cover materials over the tailings is the most effective technique for reducing radioactive emissions and dispersal of tailings. The success of such a plan, however, is dependent on ensuring the long-term integrity of these cover materials. Soil erosion from water and wind is the major natural cause of destabilizing earthen cover materials. Field data related to the control of soil loss are limited and only indirectly apply to the problem of isolation of uranium mill tailings over very long time periods (up to 80,000 a). However, sufficient information is available to determine benefits that will result from the changes in specific design variables and to evaluate the need for different design strategies among potential disposal sites. The three major options available for stabilization of uranium mill tailings are: rock cover, soil and revegetation, or a combination of both on different portions of the tailings cover. The optimal choice among these alternatives depends on site-specific characteristics such as climate and local geomorphology and soils, and on design variables such as embankment, heights and slopes, modification of upstream drainage, and revegetation practices. Generally, geomorphic evidence suggests that use of soil and vegetation alone will not be adequate to reduce erosion on slopes greater than about 5 to 9%

  16. Trace metal mobilization from oil sands froth treatment thickened tailings exhibiting acid rock drainage.

    Science.gov (United States)

    Kuznetsova, Alsu; Kuznetsov, Petr; Foght, Julia M; Siddique, Tariq

    2016-11-15

    Froth treatment thickened tailings (TT) are a waste product of bitumen extraction from surface-mined oil sands ores. When incubated in a laboratory under simulated moist oxic environmental conditions for ~450d, two different types of TT (TT1 and TT2) exhibited the potential to generate acid rock drainage (ARD) by producing acid leachate after 250 and 50d, respectively. We report here the release of toxic metals from TT via ARD, which could pose an environmental threat if oil sands TT deposits are not properly managed. Trace metal concentrations in leachate samples collected periodically revealed that Mn and Sr were released immediately even before the onset of ARD. Spikes in Co and Ni concentrations were observed both pre-ARD and during active ARD, particularly in TT1. For most elements measured (Fe, Cr, V, As, Cu, Pb, Zn, Cd, and Se), leaching was associated with ARD production. Though equivalent acidification (pH2) was achieved in leachate from both TT types, greater metal release was observed from TT2 where concentrations reached 10,000ppb for Ni, 5000ppb for Co, 3000ppb for As, 2000ppb for V, and 1000ppb for Cr. Generally, metal concentrations decreased in leachate with time during ARD and became negligible by the end of incubation (~450d) despite appreciable metals remaining in the leached TT. These results suggest that using TT for land reclamation purposes or surface deposition for volume reduction may unfavorably impact the environment, and warrants application of appropriate strategies for management of pyrite-enriched oil sands tailings streams. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Thresher sharks use tail-slaps as a hunting strategy.

    Science.gov (United States)

    Oliver, Simon P; Turner, John R; Gann, Klemens; Silvosa, Medel; D'Urban Jackson, Tim

    2013-01-01

    The hunting strategies of pelagic thresher sharks (Alopias pelagicus) were investigated at Pescador Island in the Philippines. It has long been suspected that thresher sharks hunt with their scythe-like tails but the kinematics associated with the behaviour in the wild are poorly understood. From 61 observations recorded by handheld underwater video camera between June and October 2010, 25 thresher shark shunting events were analysed. Thresher sharks employed tail-slaps to debilitate sardines at all times of day. Hunting events comprised preparation, strike, wind-down recovery and prey item collection phases, which occurred sequentially. Preparation phases were significantly longer than the others, presumably to enable a shark to windup a tail-slap. Tail-slaps were initiated by an adduction of the pectoral fins, a manoeuvre that changed a thresher shark's pitch promoting its posterior region to lift rapidly, and stall its approach. Tail-slaps occurred with such force that they may have caused dissolved gas to diffuse out of the water column forming bubbles. Thresher sharks were able to consume more than one sardine at a time, suggesting that tail-slapping is an effective foraging strategy for hunting schooling prey. Pelagic thresher sharks appear to pursue sardines opportunistically by day and night, which may make them vulnerable to fisheries. Alopiids possess specialist pectoral and caudal fins that are likely to have evolved, at least in part, for tail-slapping. The evidence is now clear; thresher sharks really do hunt with their tails.

  18. Distribution of potentially toxic elements (PTEs) in tailings, soils, and plants around Gol-E-Gohar iron mine, a case study in Iran.

    Science.gov (United States)

    Soltani, Naghmeh; Keshavarzi, Behnam; Moore, Farid; Sorooshian, Armin; Ahmadi, Mohamad Reza

    2017-08-01

    This study investigated the concentration of potentially toxic elements (PTEs) including Al, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Sb, V, and Zn in 102 soils (in the Near and Far areas of the mine), 7 tailings, and 60 plant samples (shoots and roots of Artemisia sieberi and Zygophylum species) collected at the Gol-E-Gohar iron ore mine in Iran. The elemental concentrations in tailings and soil samples (in Near and Far areas) varied between 7.4 and 35.8 mg kg -1 for As (with a mean of 25.39 mg kg -1 for tailings), 7.9 and 261.5 mg kg -1 (mean 189.83 mg kg -1 for tailings) for Co, 17.7 and 885.03 mg kg -1 (mean 472.77 mg kg -1 for tailings) for Cu, 12,500 and 400,000 mg kg -1 (mean 120,642.86 mg kg -1 for tailings) for Fe, and 28.1 and 278.1 mg kg -1 (mean 150.29 mg kg -1 for tailings) for Ni. A number of physicochemical parameters and pollution index for soils were determined around the mine. Sequential extractions of tailings and soil samples indicated that Fe, Cr, and Co were the least mobile and that Mn, Zn, Cu, and As were potentially available for plants uptake. Similar to soil, the concentration of Al, As, Co, Cr, Cu, Fe, Mn, Mo, Ni, and Zn in plant samples decreased with the distance from the mining/processing areas. Data on plants showed that metal concentrations in shoots usually exceeded those in roots and varied significantly between the two investigated species (Artemisia sieberi > Zygophylum). All the reported results suggest that the soil and plants near the iron ore mine are contaminated with PTEs and that they can be potentially dispersed in the environment via aerosol transport and deposition.

  19. TIDAL TAILS OF MINOR MERGERS: STAR FORMATION EFFICIENCY IN THE WESTERN TAIL OF NGC 2782

    International Nuclear Information System (INIS)

    Knierman, Karen; Scowen, Paul; Jansen, Rolf A.; Knezek, Patricia M.; Wehner, Elizabeth

    2012-01-01

    While major mergers and their tidal debris are well studied, they are less common than minor mergers (mass ratios ∼ SFR ) to be several orders of magnitude less than expected from the total gas density. Together with extended FUV+NUV emission from Galaxy Evolution Explorer along the tail, this indicates a low global star formation efficiency in the tidal tail producing lower mass star clusters. The H II region that we observed has a local (few-kiloparsec scale) Σ SFR from Hα that is less than that expected from the total gas density, which is consistent with other observations of tidal debris. The star formation efficiency of this H II region inferred from the total gas density is low, but normal when inferred from the molecular gas density. These results suggest the presence of a very small, locally dense region in the western tail of NGC 2782 or of a low-metallicity and/or low-pressure star-forming region.

  20. Manual for the sampling of uranium mine tailings

    International Nuclear Information System (INIS)

    Feenstra, S.; Reades, D.W.; Cherry, J.A.; Chambers, D.B.; Case, G.G.; Ibbotson, B.G.

    1983-04-01

    The purpose of this manual is to describe the requisite sampling procedures to provide a basis for the application of uniform high-quality standards to detailed geotechnical, hydrogeological, geochemical and air quality measurements at Canadian uranium tailings disposal sites. The report describes the objective and scope of a sampling program, the preliminary data collection, and the procedures for sampling of tailings solids, surface water and seepage, tailings porewater, and wind-blown dust and radon

  1. Price Tails in the Smith and Farmer's Model

    Czech Academy of Sciences Publication Activity Database

    Šmíd, Martin

    2008-01-01

    Roč. 15, č. 25 (2008), s. 31-40 ISSN 1212-074X R&D Projects: GA ČR GA402/07/1113; GA ČR(CZ) GA402/06/1417 Institutional research plan: CEZ:AV0Z10750506 Keywords : limit order market * continuous double auction * price increments * fat tails * tail exponent Subject RIV: AH - Economics http://library.utia.cas.cz/separaty/2008/E/smid-price tails in the smith and farmer's model.pdf

  2. A tale of two tails: Not just skin deep

    Directory of Open Access Journals (Sweden)

    Abhijit Dutta

    2015-01-01

    Full Text Available The dorsal cutaneous appendage or the so called human tail is a rare congenital anomaly protruding from the lumbo-sacro-coccygeal area. These caudal appendages are divided into true-tails and pseudo-tails. We report here two cases of congenital pseudo-tail with underlying spina bifida and lipo-meningocele. In this article we seek to emphasize that, as the skin and nervous systems are intimately linked by their similar ectodermal origin, a dorsal appendage may be regarded as a cutaneous marker of the underlying spinal dysraphism.

  3. Estimating impact forces of tail club strikes by ankylosaurid dinosaurs.

    Directory of Open Access Journals (Sweden)

    Victoria Megan Arbour

    Full Text Available BACKGROUND: It has been assumed that the unusual tail club of ankylosaurid dinosaurs was used actively as a weapon, but the biological feasibility of this behaviour has not been examined in detail. Ankylosaurid tail clubs are composed of interlocking vertebrae, which form the handle, and large terminal osteoderms, which form the knob. METHODOLOGY/PRINCIPAL FINDINGS: Computed tomographic (CT scans of several ankylosaurid tail clubs referred to Dyoplosaurus and Euoplocephalus, combined with measurements of free caudal vertebrae, provide information used to estimate the impact force of tail clubs of various sizes. Ankylosaurid tails are modeled as a series of segments for which mass, muscle cross-sectional area, torque, and angular acceleration are calculated. Free caudal vertebrae segments had limited vertical flexibility, but the tail could have swung through approximately 100 degrees laterally. Muscle scars on the pelvis record the presence of a large M. longissimus caudae, and ossified tendons alongside the handle represent M. spinalis. CT scans showed that knob osteoderms were predominantly cancellous, which would have lowered the rotational inertia of the tail club and made it easier to wield as a weapon. CONCLUSIONS/SIGNIFICANCE: Large knobs could generate sufficient force to break bone during impacts, but average and small knobs could not. Tail swinging behaviour is feasible in ankylosaurids, but it remains unknown whether the tail was used for interspecific defense, intraspecific combat, or both.

  4. CT findings of normal pancreatic tail: variety of morphology and location

    Energy Technology Data Exchange (ETDEWEB)

    Han, Hye Seung; Son, San Hoo; Moon, Gae Hyuk; Kim, Hu Ho; Gong Jae Chul; Yang Jae Boum [Inchon Christian Hospital, Inchon (Korea, Republic of); Park, Mee Sook [Jaesung Hospital. (Korea, Republic of)

    1998-02-01

    To determine the morphology and location of normal pancreatic tail, as seen on abdominal CT. A hundred and one patients without pancreatic disease underwent CT scanning. We then determined how to relate the location of the pancreatic tail with the splenic hilum, left kidney, and pancreatic body. We compared the thickness of the tail with that of the body and analysed of the morphology of the tail. Seventy-seven percent of all pancreatic tails were located below the splenic hilum, with 59% of this proportion located 1 to 2 cm below. Fifty percent of tails were located at the level of the uppermost quarter of the left kidney, and a further 27% at the level of the second quarter; 75 % were located in the ventrolateral portion of this kidney and 23% in the ventral portion. In 48% of patients, the pancreatic tail and body were the same thickness, and in a further 48 %, the tail was thicker than the body. In 34% of patients, the tail showed focal bulging, and in another 32%, it tapered smoothly. Forty seven percent of tails were located below the pancreatic body and a further 37% were found at the same level as the body. Abdominal CT scans showed differing morphology and location of the pancreatic tail. The recognition of these variations will diminish speculation as to their true nature. (author). 12 refs., 4 figs.

  5. Electrodialytic Remediation of Copper Mine Tailings

    DEFF Research Database (Denmark)

    Hansen, H.K.; Rojo, A.; Ottosen, L.M.

    2012-01-01

    This work compares and evaluates sixteen electrodialytic laboratory remediation experiments on copper mine tailings. Different parameters were analysed, such as remediation time, addition of desorbing agents, and the use of pulsed electrical fields.......This work compares and evaluates sixteen electrodialytic laboratory remediation experiments on copper mine tailings. Different parameters were analysed, such as remediation time, addition of desorbing agents, and the use of pulsed electrical fields....

  6. Utilisation of iron ore tailings as aggregates in concrete

    Directory of Open Access Journals (Sweden)

    Francis Atta Kuranchie

    2015-12-01

    Full Text Available Sustainable handling of iron ore tailings is of prime concern to all stakeholders who are into iron ore mining. This study seeks to add value to the tailings by utilising them as a replacement for aggregates in concrete. A concrete mix of grade 40 MPa was prepared in the laboratory with water–cement ratio of 0.5. The concrete were cured for 1, 2, 3, 7, 14 and 28 days. The properties of the concrete such as workability, durability, density, compressive strength and indirect tensile strength were tested. A controlled mix of concrete was also prepared in similar way using conventional materials and the results were compared with the tailings concrete. It was found that the iron ore tailings may be utilised for complete replacement for conventional aggregates in concrete. The iron ore tailings aggregates concrete exhibited a good mechanical strength and even in the case of compressive strength, there was an improvement of 11.56% over conventional aggregates concrete. The indirect tensile strength did not improve against the control mix due high content of fines in the tailings aggregates but showed 4.8% improvement compared with the previous study where the conventional fine aggregates was partially replaced by 20% with iron ore tailings.

  7. Cyclic steps and superimposed antidune deposits: important elements of coarse-grained deepwater channel-levée complexes

    Science.gov (United States)

    Lang, Joerg; Brandes, Christian; Winsemann, Jutta

    2017-04-01

    The facies distribution and architecture of submarine fans can be strongly impacted by erosion and deposition by supercritical density flows. We present field examples from the Sandino Forearc Basin (southern Central America), where cyclic-step and antidune deposits represent important sedimentary facies of coarse-grained channel-levée complexes. These bedforms occur in all sub-environments of the depositional systems and relate to the different stages of avulsion, bypass, levée construction and channel backfilling. Large-scale scours (18 to 29 m deep, 18 to 25 m wide, 60 to >120 m long) with an amalgamated infill, comprising massive, normally coarse-tail graded or spaced subhorizontally stratified conglomerates and pebbly sandstones, are interpreted as deposits of the hydraulic-jump zone of cyclic steps. These cyclic steps probably formed during avulsion, when high-density flows were routed into the evolving channel. The large-scale scour fills can be distinguished from small-scale channel fills based on the preservation of a steep upper margin and a coarse-grained infill comprising mainly amalgamated hydraulic-jump deposits. Channel fills include repetitive successions deposited by cyclic steps with superimposed antidunes. The hydraulic-jump zone of cyclic-step deposits comprises regularly spaced scours (0.2 to 2.6 m deep, 0.8 to 23 m wide), which are infilled by intraclast-rich conglomerates or pebbly sandstones and display normal coarse-tail grading or backsets. Laterally and vertically these deposits are associated with subhorizontally stratified, low-angle cross-stratified or sinusoidal stratified pebbly sandstones and sandstones (wavelength 0.5 to 18 m), interpreted as representing antidune deposits formed on the stoss-side of the cyclic steps during flow re-acceleration. The field examples indicate that so-called crudely or spaced stratified deposits may commonly represent antidune deposits with varying stratification styles controlled by the aggradation

  8. An M-estimator of multivariate tail dependence

    NARCIS (Netherlands)

    Krajina, A.

    2010-01-01

    AN M-ESTIMATOR OF TAIL DEPENDENCE. Extreme value theory is the part of probability and statistics that provides the theoretical background for modeling events that almost never happen. The estimation of the dependence between two or more such unlikely events (tail dependence) is the topic of this

  9. Geomorphological assessment of sites and impoundments for the long term containment of uranium mill tailings in the Alligator Rivers Region

    International Nuclear Information System (INIS)

    East, T.J.

    1985-01-01

    Current and future research into the geomorphological processes likely to affect the long term containment of uranium mill tailings in the Alligator Rivers Region is directed at three main areas: identification of geomorphic hazards at proposed impoundment sites; determination of erosion rates on impoundment slopes; and prediction of patterns of fluvial dispersal of released tailings. Each necessitates consideration of present and future geomorphic processes. Process rates during the next few thousand years might be predictable by extrapolation of contemporary and past (i.e. Holocene) climates, sea-levels and depositional environments, evidence for which is preserved in the sedimentary record. In current projects, the Late Quarternary stratigraphy of Magela Creek are examined to provide data for modelling of present and future sedimentological processes. Site stability evaluation entails recognition of present and future geomorphic hazards at impoundment sites, and includes fluvial and hillslope erosion, extreme flood events and mass movements. The life of a tailings impoundment is further determined by the intensity of erosional processes acting upon its slopes and their cover materials. A knowledge of present and future erosion rates will allow the optimisation of slope characteristics and materials in the impoundment design

  10. Some properties of Suncor oil sands tailings

    Energy Technology Data Exchange (ETDEWEB)

    Guo, C.; Wells, P.S. [Suncor Energy, Fort McMurray, AB (Canada)

    2010-07-01

    This PowerPoint presentation discussed a pond assessment program conducted by Suncor to determine the properties of mature fine tailings (MFT) and composite tailings (CT) at reclaimed and unreclaimed sites. Mudline and sonar depth sounding techniques were used to determine solids contents. A wire line sampler provided point depth samples used for laboratory analyses. Continuous drill samples were obtained in order to characterize bottom fines and clay content. A flow penetration tests was used to determine the undrained shear strength of the soft tailings. A 3-D block model was then used to estimate soft material properties and to generate material distribution volumes and tonnages for different property ranges. The study showed that the block modelling techniques provide a more accurate tailings pond assessment than traditional approaches. While slow, ongoing static consolidation was observed, surface capping and artificial dewatering are required to provide trafficable ground for the final reclamation of the sites. tabs., figs.

  11. Flotation tailings as a raw material for ceramic building materials

    Energy Technology Data Exchange (ETDEWEB)

    Burmistrov, V N; Karpunina, T I; Smolin, V N

    1986-02-01

    The VNIIstrom research institute developed a method for utilizing flotation tailings for production of bricks. Tailings are dewatered using filter presses. After dewatering, moisture content in the tailings ranges from 25 to 26%. Tailings are mixed with chamotte with a grain size to 2 mm. Using 30% chamotte improves mechanical and physical properties of the bricks and reduces energy consumption of brick firing. Tailings mixed with chamotte are granulated and dried on a conveyor. Granules with moisture content reduced to the optimum level are mixed a second time and formed in a press. The bricks are fired in a tunnel kiln with modified design. The bricks made of flotation tailings mixed with 30% chamotte are characterized by mechanical properties comparable to those of high quality bricks made of conventional materials.

  12. General review of the state of uranium milling tailings in Ukraine

    International Nuclear Information System (INIS)

    Holubiev, V.

    2002-01-01

    The mining and milling of uranium ore are produced in Ukraine since 1948. During this time eleven tailings were formed at the large territory in the region of cities Zhovty Vody and Dnepropetrovsk. One tailing is now in operation. Other ten tailings are under conservation and are producing environmental impact of different extent. Any of tailings was not subjected to recovery. By means of the enterprises, which have on their territory tailings, the monitoring is carried out for radionuclides coming in underground waters. The samples of underground water are taken from wells that are located at the tailing perimeter. The list of tailings, quantity of stored material, and radionuclides activity are submitted in the table. The supervision shows, that all tailings to some extent are the issue of radionuclides diffusion. The brief characteristic of the largest tailings is submitted. The supervision shows that all tailings to some extent are the issue of radionuclides diffusion. The brief characteristic of the largest tailings is submitted. Most of tailings are located in natural folds of a region relief, however one of them (KBG) is arranged in career with depth 60-65 m. Iron ore was mined in this career and career is located on distance 2.5 km from an inhabited zone. Career was not equipped by anti filtration barriers before it was started to fill it with sludge. In total 12.4·10 6 m 3 of tails is placed in it with general activity about 1 PBq. When tailing's filling was finished at 1991 its surface was covered by 1,7 m layer of loamy soil. The tailing creation resulted in change of hydro-geological conditions of a platform and in appearance of man-caused water-bearing horizon. The halo of pollution of underground waters is moving from the bounds of the site towards the inhabited zone of Zhovty Vody city. Now polluted by radionuclides water is detected at the distance of 1.5 km from tailing. According to forecast estimations in 15 years the pollution will move forward

  13. Leachability of solidified (Ba,Ra)SO/sub 4/ sediments in simulated settling ponds

    International Nuclear Information System (INIS)

    Constable, T.W.; Snodgrass, W.J.

    1988-01-01

    The decanted effluent from uranium tailings basins contains large amounts of dissolved Ra-226. To remove this Ra-226, the effluent is treated with barium chloride (BaCl/sub 2/) to precipitate barium-radium sulphate -(Ba,Ra)SO/sub 4/]. The sediments are stored on the bottom of the treatment pond and the treated effluent is discharged to a local water course. However, redissolution of Ra-226 fro these sediments may occur after the tailings area has been abandoned and thus cause contamination of receiving waters. This study was conducted to investigate the rate at which this dissolution occurred and to determine if this rate could be decreased by solidification of the sediments. Solidification (also referred to as chemical fixation or encapsulation) involves mixing the sediments with chemicals to produce a solid matrix analogous to concrete. The sediments used in the study were dredged in 1976 from the bottom of the North Nordic Lake settling pond in Elliot Lake, Ontario, which receives the effluent from the Nordic tailings area

  14. TAILS N-terminomic and proteomic datasets of healthy human dental pulp

    Directory of Open Access Journals (Sweden)

    Ulrich Eckhard

    2015-12-01

    Full Text Available The Data described here provide the in depth proteomic assessment of the human dental pulp proteome and N-terminome (Eckhard et al., 2015 [1]. A total of 9 human dental pulps were processed and analyzed by the positional proteomics technique TAILS (Terminal Amine Isotopic Labeling of Substrates N-terminomics. 38 liquid chromatography tandem mass spectrometry (LC-MS/MS datasets were collected and analyzed using four database search engines in combination with statistical downstream evaluation, to yield the by far largest proteomic and N-terminomic dataset of any dental tissue to date. The raw mass spectrometry data and the corresponding metadata have been deposited in ProteomeXchange with the PXD identifier ; Supplementary Tables described in this article are available via Mendeley Data (10.17632/555j3kk4sw.1.

  15. The hydrogeochemistry of four inactive tailings impoundments: Perspectives on tailings pore-water evolution

    International Nuclear Information System (INIS)

    Blowes, D.W.; Cherry, J.A.; Reardon, E.J.

    1987-01-01

    Extensive hydrogeochemical investigations are currently underway at three inactive tailings impoundments in Canada. These programs include detailed measurements of pore-water and gas-phase geochemistry through the vadose zone and the groundwater zone. An extensive piezometer network has been installed at each location to monitor the groundwater flow regime. All of the impoundments studied have been inactive for 15 to 25 years, sufficient time for extensive tailings pore-water evolution. The study areas include a very high-sulfide impoundment, a low-sulfide, high-carbonate impoundment, a low-sulfide, very low-carbonate impoundment, and a moderately high-sulfide impoundment. The pore water at each of the sites has evolved in a distinctly different and characteristic manner, representing broad styles of tailings pore-water evolution. At the high sulfide impoundment the oxidation of sulfide minerals has resulted in low pH, high redox potential conditions, with Fe 2+ concentrations in excess of 60,000 mg/L. At a depth of about 40 cm a 10 cm thick layer of ferrous and calcium sulfate minerals has precipitated. This hardpan layer limits the downward movement of O 2 and infiltrating pore waters. As a result, the pore water chemistry, both above and below the hardpan layer, has remained relatively unchanged over the past 10 years. The low-sulfide, high-carbonate tailings are sufficiently well buffered that no low pH conditions are present. The high pH conditions limit the concentrations of the metals released by sulfide mineral oxidation to levels that are two or three orders of magnitude less than is observed at the high-sulfide site. Pore waters at the low-sulfide, low-carbonate site were sampled by other researchers from the University of Waterloo

  16. Variation of Pore Water Pressure in Tailing Sand under Dynamic Loading

    Directory of Open Access Journals (Sweden)

    Jia-xu Jin

    2018-01-01

    Full Text Available Intense vibration affects the pore water pressure in a tailing dam, with the tendency to induce dam liquefaction. In this study, experiments were performed wherein model tailing dams were completely liquefied by sustained horizontal dynamic loading to determine the effects of the vibration frequency, vibration amplitude, and tailing density on the pore water pressure. The results revealed four stages in the increase of the tailing pore water pressure under dynamic loading, namely, a slow increase, a rapid increase, inducement of structural failure, and inducement of complete liquefaction. A lower frequency and smaller amplitude of the vibration were found to increase the time required to achieve a given pore water pressure in dense tailings. Under the effect of these three factors—vibration frequency and amplitude and tailing density—the tailing liquefaction time varied nonlinearly with the height from the base of the tailing dam, with an initial decrease followed by an increase. The pore pressure that induced structural failure also gradually decreased with increasing height. The increase in the tailing pore pressure could be described by an S-shaped model. A complementary multivariate nonlinear equation was also derived for predicting the tailing pore water pressure under dynamic loading.

  17. Near-threshold quantization and scattering for deep potentials with attractive tails

    International Nuclear Information System (INIS)

    Eltschka, Christopher; Moritz, Michael J.; Friedrich, Harald

    2000-01-01

    Near-threshold properties of bound and continuum states in a deep potential with an attractive tail depend essentially on a few 'tail parameters', which are determined by the properties of the potential tail beyond the region of r-values where WKB wavefunctions are accurate solutions of the Schroedinger equation. One of these tail parameters is a length parameter which defines the singular contribution to the level density just below threshold and the reflectivity of the tail of the potential just above threshold; another is a phase difference which, together with the length parameter, determines the mean scattering length. The near-threshold quantization rule and the actual scattering length are determined by the tail parameters together with a dimensionless constant depending on the zero-energy value of the WKB action integral. We study potentials with tails consisting of two inverse-power terms, V(r)∼-C α /r α -C α 1 /r α 1 ,α 1 >α>2and we derive exact analytical expressions for the tail parameters in the special case α 1 =2(α-1). This enables us to demonstrate the effect of a significant non-homogeneity of the potential tail on the results derived previously for homogeneous tails. (author)

  18. Two active galaxies with tidal tails and companions

    International Nuclear Information System (INIS)

    Keel, W.C.

    1985-01-01

    Spectroscopic, imaging, and radio observations of the tidally disturbed active systems VV 144 and I Zw 96 are presented, and indicate that the prominent optical extensions seen in both cases represent tidal tails rather than matter ejected from their nuclei (jets). This conclusion is based on the presence of stellar spectral features in the tails, lack of significant ionized gas over most of their length, and lack of radio emission outside the nuclei. Discrete knots in these tails are identified with remnant cores of the companion galaxies responsible for the morphological disturbances of the main galaxies and perhaps contributing to their nuclear activity. In both cases, the dynamics of the interactions are unusual in nature or viewing geometry. VV 144 is seen in the common plane of interaction and disk rotation, appearing strongly foreshortened. I Zw 96 shows tails associated with two companions; each is accompanied by changes in tail structure. This may be the result of a binary system of spirals colliding with a giant elliptical galaxy. 18 references

  19. Interactions of tailings leachate with local liner materials found at Canonsburg, Pennsylvania

    International Nuclear Information System (INIS)

    Dodson, M.E.; Gee, G.W.; Serne, R.J.

    1984-04-01

    The mill tailings site at Canonsburg, Pennsylvania is the first mill site to receive remedial action under the Department of Energy's Uranium Mill Tailings Remedial Action Program. Part of this remedial action will require excavating the 53,500 m 3 (70,000 yd 3 ) of tailings on the site having a specific activity exceeding 100 pCi/g, and encapsulating these contaminated tailings in a clay-lined cell. As part of the remedial action effort, Pacific Northwest Laboratory has been studying the interactions of tailings and tailings leachate with locally occurring clays proposed for liner materials. These studies include physical and chemical characterization of amended and unamended local clays, chemical characterization of the tailings, column studies of tailings leached with deionized water, and column studies of clays contacted with tailings solutions to determine the attenuation properties of the proposed liner materials. Column studies of tailings leached with deionized water indicated that the Canonsburg tailings could represent a source of soluble radium-226 and uranium-238, several trace metals, cations, and the anions SO 4 , NO 3 , and Cl. Of these soluble contaminants, uranium-238, radium-226, the trace metals As and Mo, and the anions F and SO 4 were present at levels exceeding maximum concentration levels in the tailings leaching column effluents. However, local clays, both in amended and unamended form were effective in attenuating contaminant migration. The soil amendments tested failed to increase radium attenuation. The tailings leaching studies indicated that the tailings will produce leachates of neutral pH and relatively low contaminant levels for at least 200 years. We believe that compacting the tailings within the encapsulation cell will help to reduce leaching of contaminants from the liner system, since very low permeabilities ( -8 cm/s) were observed for even slightly compacted tailings materials

  20. Spectrum of human tails: A report of six cases

    Directory of Open Access Journals (Sweden)

    Biswanath Mukhopadhyay

    2012-01-01

    Full Text Available Human tail is a curiosity, a cosmetic stigma and presents as an appendage in the lumbosacral region. Six patients of tail in the lumbosacral region are presented here to discuss the spectrum of presentation of human tails. The embryology, pathology and treatment of this entity are discussed along with a brief review of the literature.

  1. Analytical Solution and Application for One-Dimensional Consolidation of Tailings Dam

    Directory of Open Access Journals (Sweden)

    Hai-ming Liu

    2018-01-01

    Full Text Available The pore water pressure of tailings dam has a very great influence on the stability of tailings dam. Based on the assumption of one-dimensional consolidation and small strain, the partial differential equation of pore water pressure is deduced. The obtained differential equation can be simplified based on the parameters which are constants. According to the characteristics of the tailings dam, the pore water pressure of the tailings dam can be divided into the slope dam segment, dry beach segment, and artificial lake segment. The pore water pressure is obtained through solving the partial differential equation by separation variable method. On this basis, the dissipation and accumulation of pore water pressure of the upstream tailings dam are analyzed. The example of typical tailings is introduced to elaborate the applicability of the analytic solution. What is more, the application of pore water pressure in tailings dam is discussed. The research results have important scientific and engineering application value for the stability of tailings dam.

  2. Vertical Tail Buffeting Alleviation Using Piezoelectric Actuators: Some Results of the Actively Controlled Response of Buffet-Affected Tails (ACROBAT) Program

    Science.gov (United States)

    Moses, Robert W.

    1997-01-01

    A 1/6-scale F-18 wind-tunnel model was tested in the Transonic Dynamics Tunnel at the NASA Langley Research Center as part of the Actively Controlled Response Of Buffet Affected Tails (ACROBAT) program to assess the use of active controls in reducing vertical tail buffeting. The starboard vertical tail was equipped with an active rudder and the port vertical tail was equipped with piezoelectric actuators. The tunnel conditions were atmospheric air at a dynamic pressure of 14 psf. By using single-input-single-output control laws at gains well below the physical limits of the actuators, the power spectral density of the root strains at the frequency of the first bending mode of the vertical tail was reduced by as much as 60 percent up to angles of attack of 37 degrees. Root mean square (RMS) values of root strain were reduced by as much as 19 percent. Buffeting alleviation results when using the rudder are presented for comparison. Stability margins indicate that a constant gain setting in the control law may be used throughout the range of angle of attack tested.

  3. Energy resources of the west tailings pond, Airline-Sponsler Mine, Greene County, Indiana

    Energy Technology Data Exchange (ETDEWEB)

    Eggert, D.L.; Miller, L.V.; Irwin, P.N.

    1980-12-01

    The west tailings pond at the Airline-Sponsler Mine is a manmade prograding fan-delta system in which wastes from preparing coal are deposited in expected sequences. The tailings pond, originally a surface-mine final-cut and haulage road, is about 10,000 feet long, 200 to 300 feet wide, and 25 to 60 feet deep. The Indiana Geological Survey drilled eight auger holes at the pond. The first hole was 50 feet from the entry point, the second hole was 200 feet from the first, and the remaining six holes were 700 feet apart. At each hole samples were taken on 5-foot intervals, and a composite sample of each hole was also prepared. Coarse coal, dense rock fragments, and sulfide minerals settle first and are followed by medium to fine coal and clay and very fine coal. At the entry point ash is high (65.4 percent), sulfur is high (12 percent), calorific value is low (3220 Btu), and particle size is large. At the distal end ash is low near the surface but increases near the base (15.5 to 59.3 percent), sulfur is high near the surface but decreases near the base (2.6 to 1.0 percent), calorific value is high near the surface but decreases near the base (12,000 to 5250 Btu), and particle size is large near the surface but decreases near the base. Washability determinations indicate that some tailings located distally to the entry point might be reclaimed as a fuel with little further preparation and those located proximally could be upgraded by further preparation.

  4. Leachability of radioactive constituents from uranium mine tailings

    International Nuclear Information System (INIS)

    Bryant, D.N.; Cohen, D.B.; Durham, R.W.

    1979-04-01

    A project was carried out using lysimeters to determine the leaching of radioactive constituents and BaRaSO 4 from abandoned uranium mine tailings. Lime addition to the surface of acidic abandoned tailings did not reduce the level of radioactive constituents in the leachate. Considerable increases in levels of the radionuclides 230 Th, 232 Th and 22 /8Th, as well as gross alpha and beta activity in the leachate, occurred five months after recycling of BaRaSO 4 sediments to the surface layers of abandoned tailings. After nine months of leaching, the levels of 226 Ra in the leachate were 30% greater than the tailings plus sediment treatment than from tailings only (control). Another experiment compared the quality of effluent flowing over chemically-fixed (solidified) BaRaSO 4 sediments with that of non-fixed (control) in simulated sedimentation ponds. During seven months the release of 226 Ra to water from chemically-fixed BaRaSO 4 sediments remained 3 for phosphorus removal) was applied to supply 3 percent organic matter in the top 15 cm of the revegetated lysimeters. Undiluted effluent and leachate from chemically-fixed BaRaSO 4 sediments and fresh tailings were 100 percent lethal to Daphnia pulex and rainbow trout (Salmo gairdneri) in static 96-hour bioassay tests. Diluted (50 percent) effluent samples were non-toxic. (auth)

  5. Radon emanation from backfilled mill tailings in underground uranium mine.

    Science.gov (United States)

    Sahu, Patitapaban; Mishra, Devi Prasad; Panigrahi, Durga Charan; Jha, Vivekananda; Patnaik, R Lokeswara; Sethy, Narendra Kumar

    2014-04-01

    Coarser mill tailings used as backfill to stabilize the stoped out areas in underground uranium mines is a potential source of radon contamination. This paper presents the quantitative assessment of radon emanation from the backfilled tailings in Jaduguda mine, India using a cylindrical accumulator. Some of the important parameters such as (226)Ra activity concentration, bulk density, bulk porosity, moisture content and radon emanation factor of the tailings affecting radon emanation were determined in the laboratory. The study revealed that the radon emanation rate of the tailings varied in the range of 0.12-7.03 Bq m(-2) s(-1) with geometric mean of 1.01 Bq m(-2) s(-1) and geometric standard deviation of 3.39. An increase in radon emanation rate was noticed up to a moisture saturation of 0.09 in the tailings, after which the emanation rate gradually started declining with saturation due to low diffusion coefficient of radon in the saturated tailings. Radon emanation factor of the tailings varied in the range of 0.08-0.23 with the mean value of 0.21. The emanation factor of the tailings with moisture saturation level over 0.09 was found to be about three times higher than that of the absolutely dry tailings. The empirical relationship obtained between (222)Rn emanation rate and (226)Ra activity concentration of the tailings indicated a significant positive linear correlation (r = 0.95, p < 0.001). This relationship may be useful for quick prediction of radon emanation rate from the backfill material of similar nature. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Dam-break studies for mine tailings impoundments

    International Nuclear Information System (INIS)

    Jeyapalan, J.K.

    1982-01-01

    This paper describes simple procedures for performing dam-break analyses. Tailings from dam failures usually liquefy and flow for substantial distances as a viscous fluid. The prediction of the possible extent of flow slide movement is illustrated using two case histories. Topics considered include the flow behavior of liquefied talings, dimensionsless numbers for mine tailings and associated flow regimes, laminar flow, and turbulent flow. The potential inundation regions downstream of mine tailings dams are assessed. It is concluded that instances of flow slides of mine waste embankments indicate that the failure of these structures has considerable potential for damage to life and property in many cases

  7. 2015 Uranium Mill Tailings Radiation Control Act (UMTRCA) Title ll Annual Report, L-Bar, New Mexico Disposal Site

    Energy Technology Data Exchange (ETDEWEB)

    Frazier, William [USDOE Office of Legacy Management, Washington, DC (United States); Johnson, Dick [Navarro Research and Engineering, Inc., Las Vegas, NV (United States)

    2015-11-01

    The L-Bar, New Mexico, Uranium Mill Tailings Radiation Control Act (UMTRCA) Title II Disposal Site was inspected on August 18, 2015. The tailings impoundment was in excellent condition. Erosion and vegetation measurements to monitor the condition of the impoundment cover indicated that no erosion is occurring, and perennial vegetation foliar cover at the measurement plots increased substantially compared to previous years due to above-average precipitation for the year. A short segment of the perimeter fence near the site entrance was realigned in spring 2015 because a gully was undermining the fence corner. Loose fence strands at another location were repaired during the inspection, and a section of fence needs to be realigned to avoid areas affected by deep gullies and sediment deposition. Inspectors identified no other maintenance needs or cause for a follow-up inspection. Groundwater monitoring is required every 3 years. The next monitoring event will be in 2016.

  8. Recent initiatives to improve tailings and water management in the expanding Australian uranium milling industry

    International Nuclear Information System (INIS)

    Ring, R.J.; Woods, P.H.; Muller, H.B.

    2001-01-01

    This paper discusses the environmental and safety related changes that have recently occurred, or are about to be implemented in the Australian uranium milling industry. There are several drivers for these changes. The most important are the significant expansions to the Ranger and Olympic Dam uranium mills, the mining of a new orebody at Ranger and Government permission for the development of the Jabiluka deposit. The major changes in the operation of mines relate to the conservation and recycle of water, an important environmental issue in the arid country surrounding the Olympic Dam deposit, and tailings disposal strategies recently adopted or under consideration. These strategies include methods such as central thickened discharge, and cemented paste-fill for both underground and above ground disposal. The new ICRP 60 recommendations concerning radiation exposure have not been of major concern to the Australian industry, as dose rates have been historically less than the new limits. Current and expected dose rates are discussed in the context of these recommendations. (author)

  9. Orphan Stars Found in Long Galaxy Tail

    Science.gov (United States)

    2007-09-01

    Astronomers have found evidence that stars have been forming in a long tail of gas that extends well outside its parent galaxy. This discovery suggests that such "orphan" stars may be much more prevalent than previously thought. The comet-like tail was observed in X-ray light with NASA's Chandra X-ray Observatory and in optical light with the Southern Astrophysical Research (SOAR) telescope in Chile. The feature extends for more than 200,000 light years and was created as gas was stripped from a galaxy called ESO 137-001 that is plunging toward the center of Abell 3627, a giant cluster of galaxies. "This is one of the longest tails like this we have ever seen," said Ming Sun of Michigan State University, who led the study. "And, it turns out that this is a giant wake of creation, not of destruction." Chandra X-ray Image of ESO 137-001 and Tail in Abell 3627 Chandra X-ray Image of ESO 137-001 and Tail in Abell 3627 The observations indicate that the gas in the tail has formed millions of stars. Because the large amounts of gas and dust needed to form stars are typically found only within galaxies, astronomers have previously thought it unlikely that large numbers of stars would form outside a galaxy. "This isn't the first time that stars have been seen to form between galaxies," said team member Megan Donahue, also of MSU. "But the number of stars forming here is unprecedented." The evidence for star formation in this tail includes 29 regions of ionized hydrogen glowing in optical light, thought to be from newly formed stars. These regions are all downstream of the galaxy, located in or near the tail. Two Chandra X-ray sources are near these regions, another indication of star formation activity. The researchers believe the orphan stars formed within the last 10 million years or so. The stars in the tail of this fast-moving galaxy, which is some 220 million light years away, would be much more isolated than the vast majority of stars in galaxies. H-alpha Image of

  10. Remote sensing to monitor uranium tailing sites

    International Nuclear Information System (INIS)

    1992-02-01

    This report concerns the feasibility of using remotely-sensed data for long-term monitoring of uranium tailings. Decommissioning of uranium mine tailings sites may require long-term monitoring to confirm that no unanticipated release of contaminants occurs. Traditional ground-based monitoring of specific criteria of concern would be a significant expense depending on the nature and frequency of the monitoring. The objective of this study was to evaluate whether available remote-sensing data and techniques were applicable to the long-term monitoring of tailings sites. This objective was met by evaluating to what extent the data and techniques could be used to identify and discriminate information useful for monitoring tailings sites. The cost associated with obtaining and interpreting this information was also evaluated. Satellite and aircraft remote-sensing-based activities were evaluated. A monitoring programme based on annual coverage of Landsat Thematic Mapper data is recommended. Immediately prior to and for several years after decommissioning of the tailings sites, airborne multispectral and thermal infrared surveys combined with field verification data are required in order to establish a baseline for the long-term satellite-based monitoring programme. More frequent airborne surveys may be required if rapidly changing phenomena require monitoring. The use of a geographic information system is recommended for the effective storage and manipulation of data accumulated over a number of years

  11. Predicting arsenic concentrations in porewaters of buried uranium mill tailings

    Energy Technology Data Exchange (ETDEWEB)

    Langmuir, D.; Mahoney, J.; MacDonald, A.; Rowson, J.

    1999-10-01

    The proposed JEB Tailings Management Facility (TMF) to be emplaced below the groundwater table in northern Saskatchewan, Canada, will contain uranium mill tailings from McClean Lake, Midwest and Cigar Lake ore bodies, which are high in arsenic (up to 10%) and nickel (up to 5%). A serious concern is the possibility that high arsenic and nickel concentrations may be released from the buried tailings, contaminating adjacent groundwaters and a nearby lake. Laboratory tests and geochemical modeling were performed to examine ways to reduce the arsenic and nickel concentrations in TMF porewaters so as to minimize such contamination from tailings buried for 50 years and longer. The tests were designed to mimic conditions in the mill neutralization circuit (3 hr tests at 25 C), and in the TMF after burial (5--49 day aging tests). The aging tests were run at 50, 25 and 4 C (the temperature in the TMF). In order to optimize the removal of arsenic by adsorption and precipitation, ferric sulfate was added to tailings raffinates having Fe/As ratios of less than 3--5. The acid raffinates were then neutralized by addition of slaked lime to nominal pH values of 7, 8, or 9. Analysis and modeling of the test results showed that with slaked lime addition to acid tailings raffinates, relatively amorphous scorodite (ferric arsenate) precipitates near pH 1, and is the dominant form of arsenate in slake limed tailings solids except those high in Ni and As and low in Fe, in which cabrerite-annabergite (Ni, Mg, Fe(II) arsenate) may also precipitate near pH 5--6. In addition to the arsenate precipitates, smaller amounts of arsenate are also adsorbed onto tailings solids. The aging tests showed that after burial of the tailings, arsenic concentrations may increase with time from the breakdown of the arsenate phases (chiefly scorodite). However, the tests indicate that the rate of change decreases and approaches zero after 72 hrs at 25 C, and may equal zero at all times in the TMF at 4 C

  12. Sandia's activities in uranium mill tailings remedial action

    International Nuclear Information System (INIS)

    Neuhauser, S.

    1980-01-01

    The Uranium Mill Tailings Radiation Control Act of 1978 requires that remedial action be taken at over 20 inactive uranium mill tailings sites in the United States. Standards promulgated by the EPA under this act are to be the operative standards for this activity. Proposed standards must still undergo internal review, public comment, and receive Nuclear Regulatory Commission concurrence before being finalized. Briefly reviewed, the standards deal separately with new disposal sites (Part A) and cleanup of soil and contaminated structures at existing locations (Part B). In several cases, the present sites are felt to be too close to human habitations or to be otherwise unacceptably located. These tailings will probably be relocated. New disposal sites for relocated tailings must satisfy certain standards. The salient features of these standards are summarized

  13. Mine tailings composition in a historic site: implications for ecological restoration.

    Science.gov (United States)

    Courtney, R

    2013-02-01

    Ecological restoration, using tolerant plant species and nutrient additions, is a low-cost option to decrease environmental risks associated with mine tailings. An attempt was previously made to establish such a vegetation cover on an abandoned tailings facility in Southern Ireland. Historically, the tailings site has been prone to dusting and is a potential source of contamination to the surrounding environment. The site was examined to determine the success of the previous restoration plan used to revegetate the site and to determine its suitability for further restoration. Three distinct floristic areas were identified (grassland, poor grassland and bare area) based on herbage compositions and elemental analysis. Surface and subsurface samples were taken to characterise tailings from within these areas of the tailings site. The pH of bare surface tailings (pH, 2.7) was significantly more acidic (p tailings being hostile to plant growth. Total metal concentrations in tailings were high (c. 10,000 mg kg(-1) for Pb and up to 20,000 mg kg(-1) for Zn). DTPA-extractable Zn and Pb were 16 and 11 % of the total amount, respectively. Metal content in grasses growing on some areas of the tailings were elevated and demonstrated the inability of the tailings to support sustainable plant growth. Due to the inherently hostile characteristics of these areas, future restoration work will employ capping with a barrier layer.

  14. Uranium Mill Tailings Remedial Action Project, fiscal year 1995 annual report to stakeholders

    International Nuclear Information System (INIS)

    1995-01-01

    In 1978, Congress authorized the DOE to assess and clean up contamination at 24 designated former uranium processing sites. The DOE is also responsible for cleaning up properties in the vicinity of the sites where wind and water erosion deposited tailings or people removed them from the site for use in construction or landscaping projects. Cleanup is being undertaken in cooperation with state governments and Indian tribes within whose boundaries the sites are located. It is being conducted in two phases: the surface project and the ground water project. This report addresses specifics about both phases of the UMTRA Project. DOE's UMTRA Project is the world's largest materials management project ever undertaken to reduce or eliminate risk to the general public from exposure to potentially hazardous and radioactive materials. With an estimated cost at completion of nearly $2 billion for both phases of the UMTRA Project, and with the responsibility for encapsulating and isolating almost one-fourth of all the uranium mill tailings generated across the entire US (more than 44 million cubic yards), the UMTRA Project and its people have achieved a long record of safely and effectively completing its mission. It continually enhances its national reputation through its diligent process and cost efficiency as well as its international recognition for its technological innovation

  15. Recent advancements in the geotechnical characterization of oil sands tailings

    Energy Technology Data Exchange (ETDEWEB)

    Sharp, J. [Conetec, Richmond, BC (Canada)

    2010-07-01

    The technical aspects of soft oil sands tailings in-situ geotechnical site investigations were discussed. Geotechnical studies are conducted to determine containment structure stability as well as to determine volumetric and mass balances. The results of the studies are used in tailings management plans and construction activities. Flow penetrometers, field vane shear tests, and Gamma-CPTu tests are used in in-situ oil sands tailings geotechnical studies in order to determine pore pressure dissipation, and measure shear strength. Ball penetration tests are conducted to determine tailings strength. Methods of interpreting data from the tests were presented, and data from the tests were also compared and evaluated. Recommended procedures for strength screening were presented. Statistical methods for determining tailings behaviour types were outlined. The study showed that Gamma-CPTu data can be used to obtain reasonable preliminary estimates of solids and fines when combined with tailings behaviour type analyses. tabs., figs.

  16. Uranium mill tailings neutralization: contaminant complexation and tailings leaching studies

    International Nuclear Information System (INIS)

    Opitz, B.E.; Dodson, M.E.; Serne, R.J.

    1985-05-01

    Laboratory experiments were performed to compare the effectiveness of limestone (CaCO 3 ) and hydrated lime [Ca(OH) 2 ] for improving waste water quality through the neutralization of acidic uranium mill tailings liquor. The experiments were designed to also assess the effects of three proposed mechanisms - carbonate complexation, elevated pH, and colloidal particle adsorption - on the solubility of toxic contaminants found in a typical uranium mill waste solution. Of special interest were the effects each of these possible mechanisms had on the solution concentrations of trace metals such as Cd, Co, Mo, Zn, and U after neutralization. Results indicated that the neutralization of acidic tailings to a pH of 7.3 using hydrated lime provided the highest overall waste water quality. Both the presence of a carbonate source or elevating solution pH beyond pH = 7.3 resulted in a lowering of previously achieved water quality, while adsorption of contaminants onto colloidal particles was not found to affect the solution concentration of any constituent investigated. 24 refs., 8 figs., 19 tabs

  17. Modelling of contaminant release from a uranium mine tailings site

    International Nuclear Information System (INIS)

    Kahnt, Rene; Metschies, Thomas

    2007-01-01

    Available in abstract form only. Full text of publication follows: Uranium mining and milling continuing from the early 1960's until 1990 close to the town of Seelingstaedt in Eastern Germany resulted in 4 tailings impoundments with a total tailings volume of about 105 Mio. m 3 . Leakage from these tailings impoundments enters the underlying aquifers and is discharged into surface water streams. High concentration of salts, uranium and several heavy metals are released from the tailings. At present the tailings impoundments are reshaped and covered. For the identification of suitable remediation options predictions of the contaminant release for different remediation scenarios have to be made. A compartment model representing the tailings impoundments and the surrounding aquifers for the calculation of contaminant release and transport was set up using the software GOLDSIM. This compartment model describes the time dependent hydraulic conditions within the tailings and the surrounding aquifers taking into account hydraulic and geotechnical processes influencing the hydraulic properties of the tailings material. A simple geochemical approach taking into account sorption processes as well as retardation by applying a k d -approach was implemented to describe the contaminant release and transport within the hydraulic system. For uranium as the relevant contaminant the simple approach takes into account additional geochemical conditions influencing the mobility. Alternatively the model approach allows to include the results of detailed geochemical modelling of the individual tailings zones which is than used as source term for the modelling of the contaminant transport in the aquifer and to the receiving streams. (authors)

  18. Oil sands tailings treatment via surface modification of solids with polymers

    Energy Technology Data Exchange (ETDEWEB)

    Soane, D.; Ware, W.; Mahoney, R.; Kincaid, K. [Soane Energy, Cambridge, MA (United States)

    2010-07-01

    Oil sands fine tailings require large containment area and long-term storage. A recent directive has been established to reduce fluid tailings storage by 30 percent by 2012. This PowerPoint presentation described a method of treating oil sands tailings by modifying the surfaces of solids with polymers. The ATA process divided whole tailings into fines and coarse streams. The coarse stream was used to prepare anchor particles with a monolayer of tether polymers. An activator was added to the fine tailings in order to aggregate. The process cause a Velcro-like attraction between the activated fines and the tether-coated anchor particles. The solid ATA matrix trapped the fines and allowed water to drain more easily. Photographs of the process were provided. An analysis of the process demonstrated that 70 percent of the water in the tailings was recovered in less than 5 minutes. The water was clear, with less than 0.2 percent of suspended solids. The process is applicable to live tailings and mature fine tailings (MFT). tabs., figs.

  19. Identification of poorly crystalline scorodite in uranium mill tailings

    International Nuclear Information System (INIS)

    Frey, R.; Rowson, J.; Hughes, K.; Rinas, C.; Warner, J.

    2010-01-01

    The McClean Lake mill, located in northern Saskatchewan, processes a variety of uranium ore bodies to produce yellowcake. A by-product of this process is an acidic waste solution enriched in arsenic, referred to as raffinate. The raffinate waste stream is treated in the tailings preparation circuit, where arsenic is precipitated as a poorly crystalline scorodite phase. Raffinate neutralization studies have successfully identified poorly crystalline scorodite using XRD, SEM, EM, XANES and EXAFS methods, but to date, scorodite has not been successfully identified within the whole tailing solids. During the summer of 2008, a drilling program sampled the in situ tailings within the McClean Lake tailings management facility. Samples from this drilling campaign were sent to the Canadian Light Source Inc. for EXAFS analysis. The sample spectra positively identify a poorly crystalline scorodite phase within the McClean tailings management facility. (author)

  20. The Rum Jungle tailings dam - chemical profile of the subsoil

    International Nuclear Information System (INIS)

    Lowson, R.T.; Evans, J.V.; Sarbutt, J.V.; Sinclair, G.; Folk, E.

    1987-09-01

    In a survey of soils below the Rum Jungle uranium mine tailings dam, parameters measured were pH, moisture content, particle distribution, total Cu, water-extractable Cu, Ca and SO 4 and acid-extractable Ra. The cation profile had a marked discontinuity at the soil/tailings interface. This was attributed to a complex hydrogeology and to the presence of a reduction zone in the soil immediately below the tailings. The tailings acted as an aquaclude to a water table which fluctuated with the monsoonal season. The reduction zone acted as a cation trap, preventing cation transport. The radium concentration dropped to levels acceptable to public health within a few centimetres of the soil/tailings interface

  1. Can tail damage outbreaks in the pig be predicted by behavioural change?

    Science.gov (United States)

    Larsen, Mona Lilian Vestbjerg; Andersen, Heidi Mai-Lis; Pedersen, Lene Juul

    2016-03-01

    Tail biting, resulting in outbreaks of tail damage in pigs, is a multifactorial welfare and economic problem which is usually partly prevented through tail docking. According to European Union legislation, tail docking is not allowed on a routine basis; thus there is a need for alternative preventive methods. One strategy is the surveillance of the pigs' behaviour for known preceding indicators of tail damage, which makes it possible to predict a tail damage outbreak and prevent it in proper time. This review discusses the existing literature on behavioural changes observed prior to a tail damage outbreak. Behaviours found to change prior to an outbreak include increased activity level, increased performance of enrichment object manipulation, and a changed proportion of tail posture with more tails between the legs. Monitoring these types of behaviours is also discussed for the purpose of developing an automatic warning system for tail damage outbreaks, with activity level showing promising results for being monitored automatically. Encouraging results have been found so far for the development of an automatic warning system; however, there is a need for further investigation and development, starting with the description of the temporal development of the predictive behaviour in relation to tail damage outbreaks. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Reactivity of the isolated perfused rat tail vascular bed

    Directory of Open Access Journals (Sweden)

    A.S. França

    1997-07-01

    Full Text Available Isolated segments of the perfused rat tail artery display a high basal tone when compared to other isolated arteries such as the mesenteric and are suitable for the assay of vasopressor agents. However, the perfusion of this artery in the entire tail has not yet been used for functional studies. The main purpose of the present study was to identify some aspects of the vascular reactivity of the rat tail vascular bed and validate this method to measure vascular reactivity. The tail severed from the body was perfused with Krebs solution containing different Ca2+ concentrations at different flow rates. Rats were anesthetized with sodium pentobarbital (65 mg/kg and heparinized (500 U. The tail artery was dissected near the tail insertion, cannulated and perfused with Krebs solution plus 30 µM EDTA at 36oC and 2.5 ml/min and the procedures were started after equilibration of the perfusion pressure. In the first group a dose-response curve to phenylephrine (PE (0.5, 1, 2 and 5 µg, bolus injection was obtained at different flow rates (1.5, 2.5 and 3.5 ml/min. The mean perfusion pressure increased with flow as well as PE vasopressor responses. In a second group the flow was changed (1.5, 2, 2.5, 3 and 3.5 ml/min at different Ca2+ concentrations (0.62, 1.25, 2.5 and 3.75 mM in the Krebs solution. Increasing Ca2+ concentrations did not alter the flow-pressure relationship. In the third group a similar protocol was performed but the rat tail vascular bed was perfused with Krebs solution containing PE (0.1 µg/ml. There was an enhancement of the effect of PE with increasing external Ca2+ and flow. PE vasopressor responses increased after endothelial damage with air and CHAPS, suggesting an endothelial modulation of the tone of the rat tail vascular bed. These experiments validate the perfusion of the rat tail vascular bed as a method to investigate vascular reactivity

  3. Application of tailings flow analyses to field conditions

    International Nuclear Information System (INIS)

    Bryant, S.M.

    1983-01-01

    Catastrophic failures of tailings impoundments, in which liquefied tailings flow over substantial distances, pose severe hazards to the health and safety of people in downstream areas, and have a potential for economic and environmental devastation. The purpose of this study, an extension of prior investigations, was to develop procedures to measure Bingham flow parameters for mine tailings. In addition, the analytical procedures developed by Lucia (1981) and Jeyapalan (1980) for predicting the consequences of tailings flow failures were evaluated and applied to the Tenmile Tailings Pond at Climax, Colorado. Revisions in the simplified equilibrium procedure, developed by Lucia (1981), make it more compatible with infinite slope solutions. Jeyapalan's model was evaluated using a simple rheological analogy, and it appears there are some numerical difficulties with the operation of the computer program TFLOW used to model the displacements and velocities of flow slides. Comparable flow distances can be determined using either model if the flow volume used in the simplified equilibrium procedure is estimated properly. When both analytical procedures were applied to the Tenmile Pond, it was concluded there was no potential for a flow slide at the site

  4. Liner evaluation for uranium mill tailings. Final report

    International Nuclear Information System (INIS)

    Buelt, J.L.

    1983-09-01

    The Liner Evaluation for Uranium Mill Tailings Program was conducted to evaluate the need for and performance of prospective lining materials for the long-term management of inactive uranium mill tailings piles. On the basis of program results, two materials have been identified: natural foundation soil amended with 10% sodium bentonite; catalytic airblown asphalt membrane. The study showed that, for most situations, calcareous soils typical of Western US sites adequately buffer tailings leachates and prevent groundwater contamination without additional liner materials or amendments. Although mathematical modeling of disposal sites is recommended on a site-specific basis, there appears to be no reason to expect significant infiltration through the cover for most Western sites. The major water source through the tailings would be groundwater movement at sites with shallow groundwater tables. Even so column leaching studies showed that contaminant source terms were reduced to near maximum contaminant levels (MCL's) for drinking water within one or two pore volumes; thus, a limited source term for groundwater contamination exists. At sites where significant groundwater movement or infiltration is expected and the tailings leachates are alkaline, however, the sodium bentonite or asphalt membrane may be necessary

  5. Protection coverage parameters indentification for uranium tailing dumps

    International Nuclear Information System (INIS)

    Khakimov, N.; Nazarov, Kh.M.; Mirsaidov, I.U.; Akhmedov, M.Z.

    2012-01-01

    This article is devoted to protection coverage parameters indentification for uranium tailing dumps. Authors noticed that many tailing dumps In Tajikistan do not correspond to modern requirements of territories remediation published by IAEA and current norms of the Republic of Tajikistan. The most dangerous is radionuclide migration i.e., distribution of radioactive substances beyond the uranium tailing dumps territories. One of the basic distribution ways is atmospheric migration. At the same time potentially dangerous factors are: dust rising from open surfaces is the source for contamination distribution to neighboring territories; direct external exposure of public located in close distance to the sites; radioactive gas radon exhalation originating a threat if radionuclides penetration to the human body through breathing passages. Different methods of tailing's negative impact minimization, including coverage with neutral soil layer, coverage with fine-ground worked-out bentonite clay were proposed.

  6. Costs associated with tail autotomy in an ambush foraging lizard ...

    African Journals Online (AJOL)

    We induced tail autotomy in free ranging male Cordylus m. melanotus and measured potential shifts in behaviour (movements, foraging behaviour, time exposed and average distance to a potential refuge), and responses to an approaching human compared to marked individuals with complete tails. Tailed and tailless ...

  7. Estimation of bitumen and clay content in fine tailings

    International Nuclear Information System (INIS)

    Motta Cabrera, S.C.; Bryan, J.; Kantzas, A.

    2007-01-01

    Fine tailings are the components of tailings ponds and the by-product of the oil sand extraction process, consisting mostly of water with small amounts of bitumen, sand, silts and clays. Because of the large volumes of tailings, an important environmental and production process issue involves the reduction of the remaining bitumen in the tailings stream. This paper presented the results of a study that used low field nuclear magnetic resonance (NMR) in order to estimate the bitumen, clay and water content of synthetic tailings samples. NMR is a non-destructive technique that is utilized to determine compositions of oil and brine emulsions and the viscosity of heavy oil and bitumen as well as in reservoir characterization, measuring properties such as permeability, porosity, mobile and immobile fluids, and fluid saturations. The study prepared and tested numerous samples with variable water, bitumen, sand and clay concentrations in the NMR tool under ambient conditions. Two qualities of water and bitumen were used to prepare the synthetic samples. Each type of water and bitumen was analyzed as a single substance and in a mixture with the typical solids found in tailings composition. These included kaolinite, illite, sodium montmorillonite and sand. These synthetic samples were analyzed using different mixing configurations, as a function of time and in two different NMR tools. It was concluded that NMR is a potential application for on-line determination of tailings streams composition. 18 refs., 3 tabs., 17 figs

  8. Evaluation of Soils Contained in Mineral Tailings at Junin Lake

    International Nuclear Information System (INIS)

    Gomez, Javier; Fabian, Julio; Vela, Mariano

    2008-01-01

    The Junin National Reserve is located between the provinces of Junin and Pasco, Sierra Central, high land of Peru. It was analyzed 20 samples from different geographic locations soil of the Reserve. The results showed us that there are pollutants minerals very harmful to the environment because of some of the centers miners deposited the tailings in the vicinity of the nature reserve. The techniques used for characterization of mineralogical soil were: neutron activation analysis, x-ray fluorescence and spectroscopy Moessbauer by transmission. The analysis done by the method of X-ray fluorescence indicate the presence of Rubidium, tungsten, calcium, iron, nickel, copper, zinc, gold and zirconium. With spectroscopy Moessbauer technique was observed the presence a higher proportion of paramagnetic iron; while thanks to neutron activation analysis, besides these elements, it was observed the presence of Molybdenum, Manganese and a high concentration of arsenic. (authors)

  9. Evaluation of Soils Contained in Mineral Tailings at Junin Lake

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, Javier [Instituto de Investigacion de Fisica, Av. Universitaria s/n, Lima (Peru); Fabian, Julio; Vela, Mariano [Instituto Peruano de Energia Nuclear, Av. Canada 1470, San Borja, Lima (Peru)

    2008-07-01

    The Junin National Reserve is located between the provinces of Junin and Pasco, Sierra Central, high land of Peru. It was analyzed 20 samples from different geographic locations soil of the Reserve. The results showed us that there are pollutants minerals very harmful to the environment because of some of the centers miners deposited the tailings in the vicinity of the nature reserve. The techniques used for characterization of mineralogical soil were: neutron activation analysis, x-ray fluorescence and spectroscopy Moessbauer by transmission. The analysis done by the method of X-ray fluorescence indicate the presence of Rubidium, tungsten, calcium, iron, nickel, copper, zinc, gold and zirconium. With spectroscopy Moessbauer technique was observed the presence a higher proportion of paramagnetic iron; while thanks to neutron activation analysis, besides these elements, it was observed the presence of Molybdenum, Manganese and a high concentration of arsenic. (authors)

  10. Uranium mill tailings storage, use, and disposal problems

    International Nuclear Information System (INIS)

    Hendricks, D.W.

    1977-01-01

    Solid and liquid residues (tailings) containing substantial quantities of naturally occurring radionuclides are produced and stored at all US uranium mill sites. These radioactive wastes are a potential health hazard with the degree of hazard depending largely on the tailings management practices at the individual sites. The principal pathways of potential radiation exposure to man are discussed. A description is presented of some past and current tailings storage practices together with a description of some of the possible problems associated with various stabilization and disposal options. 16 figures

  11. [Assessment of anti-tremorogenic drugs--nicotine-induced tail-tremor model].

    Science.gov (United States)

    Suemaru, K; Kawasaki, H; Gomita, Y

    1997-06-01

    The repeated administration of nicotine at small doses, which do not produce whole body tremor or convulsion, causes tremor only in the tail (tail-tremor) of rats. The tremor is accompanied by locomotor hyperactivity without rigidity and immobility of the whole body, suggesting that the nicotine-induced tail-tremor model is useful for studying the mechanism underlying tremor associated with movement. The tail-tremor induced by nicotine was suppressed by mecamylamine, a nicotinic antagonist, but not by atropine or scopolamine, muscalinic antagonists. Moreover, the tail-tremor was suppressed by the beta-blockers propranolol and pindolol, as well as the benzodiazepines diazepam and clonazepam. Tremor at rest is observed only in Parkinson's disease, which is improved with anti-muscalinic drugs. Essential tremor is one of the typical tremors connected with movement (postural and kinetic tremor) and is improved with beta-blocker. These findings and results suggest that nicotine-induced tail-tremor is useful for the study of essential tremor in animal models.

  12. Ground geophysical study of the Buckeye mine tailings, Boulder watershed, Montana

    Science.gov (United States)

    McDougal, Robert R.; Smith, Bruce D.

    2000-01-01

    The Buckeye mine site is located in the Boulder River watershed along Basin Creek, in northern Jefferson County, Montana. This project is part of the Boulder River watershed Abandoned Mine Lands Initiative, and is a collaborative effort between the U.S. Geological Survey and Bureau of Land Management in the U.S. Department of the Interior, and the U.S. Forest Service in the U.S. Department of Agriculture. The site includes a large flotation milltailing deposit, which extends to the stream and meadows below the mine. These tailings contain elevated levels of metals, such as silver, cadmium, copper, lead, and zinc. Metal-rich fluvial tailings containing these metals, are possible sources of ground and surface water contamination. Geophysical methods were used to characterize the sediments at the Buckeye mine site. Ground geophysical surveys, including electromagnetics, DC resistivity, and total field magnetic methods, were used to delineate anomalies that probably correlate with subsurface metal contamination. Subsurface conductivity was mapped using EM-31 and EM-34 terrain conductivity measuring systems. The conductivity maps represent variation of concentration of dissolved solids in the subsurface from a few meters, to an approximate depth of 30 meters. Conductive sulfides several centimeters thick were encountered in a shallow trench, dug in an area of very high conductivity, at a depth of approximately 1 to1.5 meters. Laboratory measurements of samples of the sulfide layers show the conductivity is on the order of 1000 millisiemens. DC resistivity soundings were used to quantify subsurface conductivity variations and to estimate the depth to bedrock. Total field magnetic measurements were used to identify magnetic metals in the subsurface. The EM surveys identified several areas of relatively high conductivity and detected a conductive plume extending to the southwest, toward the stream. This plume correlates well with the potentiometric surface and direction of

  13. Electrodialytic remediation of suspended mine tailings

    DEFF Research Database (Denmark)

    Hansen, Henrik K.; Rojo, Adrian; Pino, Denisse

    2008-01-01

    This work shows the laboratory results of nine electrodialytic remediation experiments on copper mine tailings. A newly designed remediation cell, where the solids were kept in suspension by airflow, was tested. The results show that electric current could remove copper from suspended tailings...... efficiency from 1% to 80% compared to experiments with no stirring but with the same operational conditions. This showed the crucial importance of having the solids in suspension and not settled during the remediation....

  14. Managing 'tail liability'.

    Science.gov (United States)

    Frese, Richard C; Weber, Ryan J

    2013-11-01

    To reduce and control their level of tail liability, hospitals should: Utilize a self-insurance vehicle; Consider combined limits between the hospital and physicians; Communicate any program changes to the actuary, underwriter, and auditor; Continue risk management and safety practices; Ensure credit is given to the organization's own medical malpractice program.

  15. A review on in situ phytoremediation of mine tailings.

    Science.gov (United States)

    Wang, Li; Ji, Bin; Hu, Yuehua; Liu, Runqing; Sun, Wei

    2017-10-01

    Mine tailings are detrimental to natural plant growth due to their physicochemical characteristics, such as high pH, high salinity, low water retention capacity, high heavy metal concentrations, and deficiencies in soil organic matter and fertility. Thus, the remediation of mine tailings has become a key issue in environmental science and engineering. Phytoremediation, an in situ cost-effective technology, is emerging as the most promising remediation method for mine tailings by introducing tolerant plant species. It is particularly effective in dealing with large-area mine tailings with shallow contamination of organic, nutrient and metal pollutants. In this review, the background, concepts and applications of phytoremediation are comprehensively discussed. Furthermore, proper amendments used to improve the physical, chemical and biological properties of mine tailings are systematically reviewed and compared. Emphasis is placed on the types and characteristics of tolerant plants and their role in phytoremediation. Moreover, the role of microorganisms and their mechanism in phytoremediation are also discussed in-depth. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Reclamation plans at uranium mill tailings sites

    International Nuclear Information System (INIS)

    Abt, S.R.; Nelson, J.D.

    1990-01-01

    Long-term stability of waste impoundments is of concern because of the long time periods over which various types of waste may remain active. Over the past decade much technology has been developed specifically for reclamation of uranium mill tailings impoundments. Aspects of this technology will be discussed here and is presented as also being directly applicable to reclamation of industrial waste impoundments in general. The paper discusses Title I and Title II sites which represent two different generations in uranium tailings impoundment construction. The comparison between the two represent differences in philosophies as well as in impoundment type. Reclamation of uranium mill tailings impoundments in the U.S. is controlled by Federal legislation, which has set forth the regulatory framework for reclamation plan approval. Title I requirements govern government owned inactive sites and Title II requirements govern active tailings impoundments or those operated by private industries. While the Title I and Title II designation may result in a slightly different regulatory process, reclamation of uranium tailings sites has the same. Differences between Title I and Title II reclamation plans to achieve surface stability relate primarily to the embankment and surface covers. The differences in the cover designs result from site-specific conditions, rather than from differences in engineering approaches or the regulatory process. This paper discusses the site-specific conditions that affect the selection of cover designs, and provides a comparative example to illustrate the effect of this condition

  17. Recent hydrological observations from the Riverton and Maybell tailings piles

    International Nuclear Information System (INIS)

    Tokunaga, T.; Narasimhan, T.N.

    1982-01-01

    This paper reports on field and laboratory hydrologic studies of two inactive uranium mill tailings piles under the Uranium Mill Tailings Remedial Action Program (UMTRA). The ultimate goal of the studies is to evaluate the nature of the contaminant potential of the piles with sufficient detail so that appropriate remedial measures can be designed and implemented under the UMTRA Program. The field studies included the monitoring of hydraulic head profiles of the piles and infiltration tests. Both the field and laboratory results from the Riverton tailings indicate a great deal of spatial variability in hydraulic properties. It is determined that the bulk of the precipitation input at the Riverton tailings is lost by evapotranspiration within the upper meter of soil cover and tailings

  18. Uranium-bearing and associated minerals in their geochemical and sedimentological context, Elliot Lake, Ontario

    International Nuclear Information System (INIS)

    Theis, N.J.

    1979-01-01

    The depositional energy environment of the Rio Algom-Denison ore reef was investigated on a regional scale using several parameters including pebble size. Regional trends of decreasing pebble size coincide with the regional direction of sediment transport. Pebble size was also used to characterize the depositional energy environment at the sample level. Quartz-pebble size and pyrite-grain size as determined from the same samples have a correlation coefficient of 0.93 which indicates that the coarse granular pyrite is detrital. Bulk chemical analyses of selected elements (U, Th, Pb, Ti, Ce, La, Y and Zr) which were chosen to reflect specific minerals (uraninite, brannerite, monazite and zircon), showed strong correlation with quartz-pebble size of the respective samples. Electron microprobe analyses of uraninite and brannerite are reported. The uraninites have typical pegmatitic compositions. Several types of brannerite are described; the conclusion reached is that although some brannerite may be detrital, most of it formed by adsorption of uranium onto titania collectors. Redistribution of some of the uranium has not changed the placer nature of the ore reef. Genesis of individual minerals (pyrite, uraninite, brannerite, zircon and monazite) is discussed. It is concluded that the mineralogy and its geochemical expression have been controlled by processes of fluvial deposition. As a result of the regional patterns in depositional environment, the ore reef shows a broad mineralogical zoning. Fluctuations in depositional energy have also produced lithologically related mineral zoning on a smaller scale. (author)

  19. Radium and heavy metal transport beneath an abandoned uranium tailings dam

    International Nuclear Information System (INIS)

    Jeffery, J.J.; Sinclair, G.; Lowson, R.T.

    1988-09-01

    An abandoned uranium tailings dam at Moline in the Northern Territory of Australia was the site of a study to assess the movement of potentially toxic elements from tailings into subsoil. The tailings at Moline were first laid down in 1959 and have since been leached by prevailing rainfall. Sixteen sampling sites were selected to give a good representation of the dam. At each site, a trench was excavated through the tailings and into the subsoil, then samples of subsoil were taken at 10 cm intervals down to a depth of 50 cm. A sample of the tailings overlying the tailings-subsoil interface was also taken. Samples were analysed for radium, uranium, copper, zinc, and lead. At most sites there was only minor accumulation of these elements in the 0-10 cm subsoil layer immediately below the interface, with concentrations typically one or two orders of magnitude less than the concentrations in overlying tailings. Below 10 cm, the concentrations were typically at or close to background concentrations

  20. Tailings technology. Decommissioning and rehabilitation remedial action technology development

    International Nuclear Information System (INIS)

    Ramsey, R.W. Jr.

    1982-01-01

    This paper is to provide an overview of technology requirements for long-term uranium mill tailings disposal and remedial actions for existing tailings to ensure their adequate disposal. The paper examines the scientific disciplines that are the basis for the technology of uranium mill tailings stabilization and the design of barriers to control radiological exposure or environmental degradation at the location of tailings disposal. The discussion is presented as a hypothetical course of instruction at a fictitious university. Features of six mechanisms of dispersal or intrusion are examined with brief discussion of the applicable technology development for each. The paper serves as an introduction to subsequent specific technology development papers in the session. (author)

  1. Long-term ecological behaviour of abandoned uranium mill tailings

    International Nuclear Information System (INIS)

    Kalin, Margarete

    1984-12-01

    Semi-aquatic and terrestrial areas on abandoned or inactive uranium mill tailings in Ontario were studied in order to identify the growth characteristics of the naturally invading species dominating these areas. Semi-aquatic areas of tailings sites have been invaded by cattails. These species formed wetland communities which varied in size, but all were essentially monocultures of Typha latifolia, T. angustifolia, or of the hybrids T. glauca. Sedges, Scripus cyperinus (wool-grass) and Phragmites australis (reed-grass), were found in transition zones between the cattail stand and the dry section of the tailings site. The expansion of the cattail stands appeared to be controlled by the hydrological conditions on the site, rather than the chemical characteristics of the tailings

  2. Kelvin-Helmholtz instability in type-1 comet tails and associated phenomena

    International Nuclear Information System (INIS)

    Ershkovich, A.I.

    1980-01-01

    Selected problems of the solar wind - comet tail coupling that are currently accessible to quantitative analysis are reviewed. The model of a comet tail as a plasma cylinder separated by a tangential discontinuity surface from the solar wind is discussed in detail. This model is compatible with the well-known Alfven mechanism of formation of the comet tail. The stability problem of the comet tail boundary (considered as a discontinuity surface) is solved. Under typical conditions a comet tail boundary can undergo the Kelvin-Helmholtz instability. With finite amplitude the stabilizing effect of the magnetic field increases, and waves become stabilized. This model supplies a detailed quantitative description of helical waves observed in type-1 comet tails. A more general model of the tail boundary as a transition layer with a continuous change of the plasma parameters within it is also considered. This theory, in principle, enables us to solve one of the fundamental problems of cometary physics: the magnetic field of the comet tail can be derived from the observations of helical waves. This field turns out to be of the order of the interplanetary field. Various other considerations, discussed in this review also support this conclusion. (orig.)

  3. Modulation of 5' splice site selection using tailed oligonucleotides carrying splicing signals

    Directory of Open Access Journals (Sweden)

    Elela Sherif

    2006-01-01

    Full Text Available Abstract Background We previously described the use of tailed oligonucleotides as a means of reprogramming alternative pre-mRNA splicing in vitro and in vivo. The tailed oligonucleotides that were used interfere with splicing because they contain a portion complementary to sequences immediately upstream of the target 5' splice site combined with a non-hybridizing 5' tail carrying binding sites for the hnRNP A1/A2 proteins. In the present study, we have tested the inhibitory activity of RNA oligonucleotides carrying different tail structures. Results We show that an oligonucleotide with a 5' tail containing the human β-globin branch site sequence inhibits the use of the 5' splice site of Bcl-xL, albeit less efficiently than a tail containing binding sites for the hnRNP A1/A2 proteins. A branch site-containing tail positioned at the 3' end of the oligonucleotide also elicited splicing inhibition but not as efficiently as a 5' tail. The interfering activity of a 3' tail was improved by adding a 5' splice site sequence next to the branch site sequence. A 3' tail carrying a Y-shaped branch structure promoted similar splicing interference. The inclusion of branch site or 5' splice site sequences in the Y-shaped 3' tail further improved splicing inhibition. Conclusion Our in vitro results indicate that a variety of tail architectures can be used to elicit splicing interference at low nanomolar concentrations, thereby broadening the scope and the potential impact of this antisense technology.

  4. Radioactivity in soil and air near the Sillamaee tailings depository

    International Nuclear Information System (INIS)

    Realo, E.

    2002-01-01

    Radiological situation outside the Sillamaee plant and U/Th tailings depository is studied by soil monitoring and modelling methods. In the Sillamaee region, the reliable monitoring and assessment of the technological impact to public exposure is significantly interfered with the complex nature of natural background (e.g., elevated and variable soil concentrations of 226 Ra in the range of 40 .. 320 Bq kg -1 , high outdoor 222 Rn levels, etc.). The releases of radionuclides from the tailing depository to the ground and tap water are negligible. The major water pathway is the release to the Gulf of Finland and specifically the consumption of fish. The isotopes 234 U, 238 U (about 6.2 GBq a -1 or 0.025 % of the total U per year) and 210 Pb (∼ 0.05 GBq a -1 ) dominate in the source term. A compartmental modelling of this pathway has demonstrated a low radiological impact to the population with the individual and collective committed doses of 1 μSv and 1 manSv, respectively, for both current leakage and sudden dam collapse scenarios. We have determined the depth distribution of radionuclides in soil profiles to find an evidence for airborne radionuclide deposition. Samples collected in the Sillamaee town (up to 1 .. 2 km from the depository) have been analysed by using low background Ge(Li) and HPGe gamma spectrometry. The results demonstrate an enhanced (relative to the bottom layers) 226 Ra and 238 U content in the surface soil layers. A similar observation has been found near the oil-shale-fired power plants in NE Estonia, which we attributed to the long term deposition of fly-ash radionuclides. It should be noted that in the non-polluted locations over Estonia the 226 Ra concentration in the uppermost 0 .. 3 cm layer is about 11 % less than in the next 3 cm thick soil layers. In the ground level air, the mean dust loads of 0.23 mg m -3 (0.02 to 1.6 mg m -3 ) have been measured (V. Nossov, SILMET, 1997, private communication and [6]) with the aerosol beta

  5. Fat-tailed sheep in Indonesia; an essential resource for smallholders.

    Science.gov (United States)

    Udo, Henk Mathijs Johannes; Budisatria, I Gede Suparta

    2011-10-01

    This paper discusses the historical development of fat-tailed sheep in Indonesia, the dynamics of production systems, production and reproduction performances under farmers' conditions, and roles of sheep in livelihoods. In the eighteenth and nineteenth century, fat-tailed sheep from southwest Asia and Africander sheep from South Africa were introduced. Crossing of fat-tailed sheep with the local thin-tailed sheep produced the Javanese fat-tailed sheep. Main motives for the gradual change-over to fat-tailed sheep have been their potential larger body size and the preference of consumers for their meat. Management systems are changing in response to the intensification of land use. The reproductive performances of fat-tailed sheep are good. Households keep four to six animals, housed close to the family quarters. This results in very high levels of faecal bacteria contamination of drinking water sources. Sheep provide a small income, manure, security and help to accumulate capital. Sheep also play a key role in religious festivities. Farmers hardly profit from the increased demand for the feast of sacrifice; animals are sold mainly when the owners have urgent cash needs. Systematic sheep fattening can contribute to higher economic results, if sufficient family labour and crop residues are available.

  6. Dewatering tailings impoundments : interior drains

    International Nuclear Information System (INIS)

    Charlie, W.A.; Doehring, D.O.; Durnford, D.S.

    1984-01-01

    For the design of a new uranium tailings impoundment in the western United States, it was proposed that an interior drainage system be considered to economically and reliably minimize potential short- and long-term environmental impacts. The objectives were to decrease the effective hydraulic head on the clay liner, to dewater and stabilize the tailings, and to increase the amount of water recycled to the mill. In addition, desaturation of the impoundment would induce capillary pressure (negative porewater pressure), further reducing the potential movement of dissolved pollutants. This paper presents saturated and unsaturated seepage principles and reviews the concept, criteria and design of the various interior drainage systems considered

  7. Computer simulations of long-time tails: what's new?

    NARCIS (Netherlands)

    Hoef, van der M.A.; Frenkel, D.

    1995-01-01

    Twenty five years ago Alder and Wainwright discovered, by simulation, the 'long-time tails' in the velocity autocorrelation function of a single particle in fluid [1]. Since then, few qualitatively new results on long-time tails have been obtained by computer simulations. However, within the

  8. Comparing downside risk measures for heavy tailed distributions

    NARCIS (Netherlands)

    Daníelsson, J.; Jorgensen, B.N.; Sarma, M.; Vries, de C.G.

    2006-01-01

    Using regular variation to define heavy tailed distributions, we show that prominent downside risk measures produce similar and consistent ranking of heavy tailed risk. Thus, regardless of the particular risk measure being used, assets will be ranked in a similar and consistent manner for heavy

  9. Recycling of asbestos tailings used as reinforcing fillers in polypropylene based composites.

    Science.gov (United States)

    Zhai, Wensi; Wang, Yao; Deng, Yuan; Gao, Hongli; Lin, Zhen; Li, Mao

    2014-04-15

    In this work, asbestos tailings were recycled and used as reinforcing fillers to enhance the mechanical properties of polypropylene (PP). A silane coupling agent was used to chemically modify the asbestos tailings to increase the compatibility between asbestos tailings and polypropylene matrix. Both raw and chemically treated asbestos tailings with different loading levels (from 3 to 30 wt%) were utilized to fabricate composites. Mechanical properties of these composites have been investigated by dynamic mechanical analysis, tensile test and notched impact test. Results showed that hybridization of asbestos tailings in the composites enhanced the mechanical properties of neat PP evidently, and treated asbestos tailings/PP composites yielded even better mechanical properties compared with those of raw asbestos tailings/PP composites. This recycling method of asbestos tailings not only reduces disposal costs and avoids secondary pollution but also produces a new PP-based composite material with enhanced mechanical properties. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Arsenic readily released to pore waters from buried mill tailings

    Energy Technology Data Exchange (ETDEWEB)

    Mahoney, John [Hydrologic Consultants, Inc., 143 Union Blvd., Suite 525, Lakewood, CO 80228 (United States)]. E-mail: jmahoney@hcico.com; Langmuir, Donald [Hydrochem Systems Corp., P.O. Box 17090, Golden, CO 80402 (United States); Gosselin, Neil [Department of Chemistry and Biochemistry, University of Regina, 3737 Wascana Way, Regina, SK, S4S 0A2 (Canada); Rowson, John [COGEMA Resources, Inc., P.O. Box 9204, Saskatoon, SK, S7K 3X5 (Canada)

    2005-05-15

    At the McClean Lake Operation in the Athabasca Basin of northern Saskatchewan, the untreated acid raffinate solutions associated with U mill tailings contain up to 700 mg/L dissolved As. To reduce the concentration of As and other contaminants in acid tailing slurries at the JEB mill at McClean Lake, ferric sulfate may be added to the acid raffinates to assure that their molar Fe/As ratio equals or exceeds 3. Tailings slurries are then neutralized with lime to pH 4, and subsequently to pH 7-8. The neutralized tailings contain minerals from the original ore, which are chiefly quartz, illite, kaolinite and chlorite, and precipitated (secondary) minerals that include gypsum, scorodite, annabergite, hydrobasaluminite and ferrihydrite. Most of the As is associated with the secondary arsenate minerals, scorodite and annabergite. However, a few percent is adsorbed and/or co-precipitated, mainly by ferrihydrite. Of major concern to provincial and federal regulators is the risk that significant amounts of As might be released from the tailings to pore waters after their subaqueous disposal in the tailings management facility. A laboratory study was performed to address this issue, measuring readily desorbed As using a method known as equilibrium partitioning in closed systems (EPICS). The EPICS method was selected because it employs a leaching solution that, except for its As concentration, is identical in composition to the neutralized raffinate in contact with the tailings. Laboratory experiments and modeling results demonstrated that the As that could be readily released to pore waters is about 0.2% of the total As in the tailings. Long-term, such releases may contribute no more than a few mg/L of dissolved As to tailings pore waters.

  11. Arsenic readily released to pore waters from buried mill tailings

    International Nuclear Information System (INIS)

    Mahoney, John; Langmuir, Donald; Gosselin, Neil; Rowson, John

    2005-01-01

    At the McClean Lake Operation in the Athabasca Basin of northern Saskatchewan, the untreated acid raffinate solutions associated with U mill tailings contain up to 700 mg/L dissolved As. To reduce the concentration of As and other contaminants in acid tailing slurries at the JEB mill at McClean Lake, ferric sulfate may be added to the acid raffinates to assure that their molar Fe/As ratio equals or exceeds 3. Tailings slurries are then neutralized with lime to pH 4, and subsequently to pH 7-8. The neutralized tailings contain minerals from the original ore, which are chiefly quartz, illite, kaolinite and chlorite, and precipitated (secondary) minerals that include gypsum, scorodite, annabergite, hydrobasaluminite and ferrihydrite. Most of the As is associated with the secondary arsenate minerals, scorodite and annabergite. However, a few percent is adsorbed and/or co-precipitated, mainly by ferrihydrite. Of major concern to provincial and federal regulators is the risk that significant amounts of As might be released from the tailings to pore waters after their subaqueous disposal in the tailings management facility. A laboratory study was performed to address this issue, measuring readily desorbed As using a method known as equilibrium partitioning in closed systems (EPICS). The EPICS method was selected because it employs a leaching solution that, except for its As concentration, is identical in composition to the neutralized raffinate in contact with the tailings. Laboratory experiments and modeling results demonstrated that the As that could be readily released to pore waters is about 0.2% of the total As in the tailings. Long-term, such releases may contribute no more than a few mg/L of dissolved As to tailings pore waters

  12. Summary of the engineering assessment of inactive uranium mill tailings

    International Nuclear Information System (INIS)

    1981-07-01

    The Grand Junction site has been reevaluated in order to revise the october 1977 engineering assessment of the problems resulting from the existence of radioactive uranium mill tailings at Grand Junction, Colorado. This engineering assessment has included the preparation of topographic maps, the performance of core drillings and radiometric measurements sufficient to determine areas and volumes of tailings and radiation exposures of individuals and nearby populations, the investigations of site hydrology and meteorology, and the evaluation and costing of alternative corrective actions. Radon gas released from the 1.9 million tons of tailings at the Grand Junction site constitutes the most significant environmental impact, although windblown tailings and external gamma radiation are also factors. The eight alternative actions presented herein range from millsite and off-site decontamination with the addition of 3 m of stabilization cover material (Option I), to removal of the tailings to remote disposal sites and decontamination of the tailings site (Option II through VIII). Cost estimates for the eight options range from about $10,200,000 for stabilization in-place to about $39,500,000 for disposal in the DeBeque area, at a distance of about 35 mi, using transportation by rail. If transportation to DeBeque were by truck, the cost is estimated to be about $41,900,000. Three prinicpal alternatives for the reprocessing of the Grand Junction tailings were examined: (a) heap leaching; (b) treatment at an existing mill; and (c) reprocessing at a new conventional mill constructed for tailings reprocessing. The cost of the uranium recovered would be about $200/lb by heap leach and $150/lb by conventional plant processes. The spot market price for uranium was $25/lb early in 1981. Therefore, reprocessing the tailings for uranium recovery appears not to be economically attractive

  13. Giant Metrewave Radio Telescope Observations of Head–Tail Radio Galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Sebastian, Biny; Lal, Dharam V.; Rao, A. Pramesh, E-mail: biny@ncra.tifr.res.in [National Center for Radio Astrophysics—Tata Institute of Fundamental Research Post Box 3, Ganeshkhind P.O., Pune 41007 (India)

    2017-10-01

    We present results from a study of seven large known head–tail radio galaxies based on observations using the Giant Metrewave Radio Telescope at 240 and 610 MHz. These observations are used to study the radio morphologies and distribution of the spectral indices across the sources. The overall morphology of the radio tails of these sources is suggestive of random motions of the optical host around the cluster potential. The presence of multiple bends and wiggles in several head–tail sources is possibly due to the precessing radio jets. We find steepening of the spectral index along the radio tails. The prevailing equipartition magnetic field also decreases along the radio tails of these sources. These steepening trends are attributed to the synchrotron aging of plasma toward the ends of the tails. The dynamical ages of these sample sources have been estimated to be ∼10{sup 8} yr, which is a factor of six more than the age estimates from the radiative losses due to synchrotron cooling.

  14. Measurement and calculation of radon releases from uranium mill tailings

    International Nuclear Information System (INIS)

    1992-01-01

    The mining and milling of uranium ores produces large quantities of radioactive wastes. Although relatively small in magnitude compared to tailings from metal mining and extraction processes, the present worldwide production of such tailings exceeds 20 million tonnes annually. There is thus a need to ensure that the environmental and health risks from these materials are reduced to an acceptable level. This report has been written as a complement to another publication entitled Current Practices for the Management and Confinement of Uranium Mill Tailings, IAEA Technical Reports Series No. 335, which provides a general overview of all the important factors in the siting, design and construction of tailings impoundments, and in the overall management of tailings with due consideration give to questions of the release of pollutants from tailings piles. The present report provides a comprehensive overview of the release, control and monitoring of radon, including computational methods. The report was first drafted in 1989 and was then reviewed at an Advisory Group meeting in 1990. 42 refs, 9 figs, 3 tabs

  15. A tale too long for a tail too short? : identification of characteristics in pigs related to tail biting and other oral manipulations directed at conspecifics

    NARCIS (Netherlands)

    Ursinus, W.W.

    2014-01-01

    Ursinus, W.W. (2014). A tale too long for a tail too short? Identification of

    characteristics in pigs related to tail biting and other oral manipulations directed

    at conspecifics. PhD thesis, Wageningen University, The Netherlands.

    Tail biting in pigs, i.e. the chewing on and

  16. Risk Management - Variance Minimization or Lower Tail Outcome Elimination

    DEFF Research Database (Denmark)

    Aabo, Tom

    2002-01-01

    on future cash flows (the budget), while risk managers concerned about costly lower tail outcomes will hedge (considerably) less depending on the level of uncertainty. A risk management strategy of lower tail outcome elimination is in line with theoretical recommendations in a corporate value......This paper illustrates the profound difference between a risk management strategy of variance minimization and a risk management strategy of lower tail outcome elimination. Risk managers concerned about the variability of cash flows will tend to center their hedge decisions on their best guess......-adding perspective. A cross-case study of blue-chip industrial companies partly supports the empirical use of a risk management strategy of lower tail outcome elimination but does not exclude other factors from (co-)driving the observations....

  17. Long-Term Performance of Uranium Tailings Disposal Cells - 13340

    International Nuclear Information System (INIS)

    Bostick, Kent; Daniel, Anamary; Pill, Ken; Tachiev, Georgio; Noosai, Nantaporn; Villamizar, Viviana

    2013-01-01

    Recently, there has been interest in the performance and evolution of Uranium Mill Tailings Remedial Action (UMTRA) Project disposal cell covers because some sites are not compliant with groundwater standards. Field observations of UMTRA disposal cells indicate that rock covers tend to become vegetated and that saturated conductivities in the upper portion of radon barriers may increase due to freeze/thaw cycles and biointrusion. This paper describes the results of modeling that addresses whether these potential changes and transient drainage of moisture in the tailings affect overall performance of the disposal cells. A numerical unsaturated/saturated 3-dimensional flow model was used to simulate whether increases in saturated conductivities in radon barriers with rock covers affect the overall performance of the disposal cells using field data from the Shiprock, NM, UMTRA site. A unique modeling approach allowed simulation with daily climatic conditions to determine changes in moisture and moisture flux from the disposal cell. Modeling results indicated that increases in the saturated conductivity at the top of radon barrier do not influence flux from the tailings with time because the tailings behave similar hydraulically to the radon barrier. The presence of a thin layer of low conductivity material anywhere in the cover or tailings restricts flux in the worst case to the saturated conductivity of that material. Where materials are unsaturated at depth within the radon barrier of tailings slimes, conductivities are typically less than 10 -8 centimeters per second. If the low conductivity layer is deep within the disposal cell, its saturated properties are less likely to change with time. The significance of this modeling is that operation and maintenance of the disposal cells can be minimized if they are allowed to progress to a natural condition with some vegetation and soil genesis. Because the covers and underlying tailings have a very low saturated

  18. Long-Term Performance of Uranium Tailings Disposal Cells - 13340

    Energy Technology Data Exchange (ETDEWEB)

    Bostick, Kent; Daniel, Anamary; Pill, Ken [Professional Project Services, Inc., 1100 Bethel Valley Road, Oak Ridge, TN, 37922 (United States); Tachiev, Georgio; Noosai, Nantaporn; Villamizar, Viviana [Florida International University, 10555 W. Flagler St., EC 2100, Miami FL, 33174 (United States)

    2013-07-01

    Recently, there has been interest in the performance and evolution of Uranium Mill Tailings Remedial Action (UMTRA) Project disposal cell covers because some sites are not compliant with groundwater standards. Field observations of UMTRA disposal cells indicate that rock covers tend to become vegetated and that saturated conductivities in the upper portion of radon barriers may increase due to freeze/thaw cycles and biointrusion. This paper describes the results of modeling that addresses whether these potential changes and transient drainage of moisture in the tailings affect overall performance of the disposal cells. A numerical unsaturated/saturated 3-dimensional flow model was used to simulate whether increases in saturated conductivities in radon barriers with rock covers affect the overall performance of the disposal cells using field data from the Shiprock, NM, UMTRA site. A unique modeling approach allowed simulation with daily climatic conditions to determine changes in moisture and moisture flux from the disposal cell. Modeling results indicated that increases in the saturated conductivity at the top of radon barrier do not influence flux from the tailings with time because the tailings behave similar hydraulically to the radon barrier. The presence of a thin layer of low conductivity material anywhere in the cover or tailings restricts flux in the worst case to the saturated conductivity of that material. Where materials are unsaturated at depth within the radon barrier of tailings slimes, conductivities are typically less than 10{sup -8} centimeters per second. If the low conductivity layer is deep within the disposal cell, its saturated properties are less likely to change with time. The significance of this modeling is that operation and maintenance of the disposal cells can be minimized if they are allowed to progress to a natural condition with some vegetation and soil genesis. Because the covers and underlying tailings have a very low saturated

  19. From Globular Clusters to Tidal Dwarfs: Structure Formation in Tidal Tails

    Science.gov (United States)

    Knierman, K.; Hunsberger, S.; Gallagher, S.; Charlton, J.; Whitmore, B.; Hibbard, J.; Kundu, A.; Zaritsky, D.

    1999-12-01

    Galaxy interactions trigger star formation in tidal debris. How does this star formation depend on the local and global physical conditions? Using WFPC2/HST images, we investigate the range of structure within tidal tails of four classic ``Toomre Sequence'' mergers: NGC 4038/9 (``Antennae''), NGC 7252 (``Atoms for Peace''), NGC 3921, and NGC 3256. These tails contain a variety of stellar associations with sizes from globular clusters up to dwarf Irregulars. We explore whether there is a continuum between the two extremes. Our eight fields sample seven tidal tails at a variety of stages in the evolutionary sequence. Some of these tails are rich in HI while others are HI poor. Large tidal dwarfs are embedded in three of the tails. Using V and I WFPC2 images, we measure luminosities and colors of substructures within the tidal tails. The properties of globular cluster candidates in the tails will be contrasted with those of the hundreds of young clusters in the central regions of these mergers. We address whether globular clusters form and survive in the tidal tails and whether tidal dwarfs are composed of only young stars. By comparing the properties of structures in the tails of the four mergers with different ages, we examine systematic evolution of structure along the evolutionary sequence and as a function of HI content. We acknowledge support from NASA through STScI, and from NSF for an REU supplement for Karen Knierman.

  20. A Study of lymphangiogenesis in a gecko model of tail autotomy

    International Nuclear Information System (INIS)

    Tsopelas, C.; Munns, S.L.; Lewis, B.; Daniels, C.B.; Cooter, R.D.; Chatterton, B.E.

    2002-01-01

    Full text: Lymphoedema is a debilitating problem for which there is no effective cure. Lymphatic vessels do not regenerate after injuries such as infection, trauma, radiotherapy or tumour invasion. One approach is to determine whether lymph vessels can be regenerated in tissues where these structures have been damaged or removed. This study examined lymphangiogenesis in a gecko model of tail autotomy. Christinus marmoratus can regenerate its tail which is non-oedematous. The lymphatics of gecko tails were visualised using 99m Tc-Sb 2 S 3 colloid, image analyses provided lymph speed and % activity migrated from the injection site. Histological images yielded density and diameter of lymphatic vessels. Measurements were obtained for geckos with non-regenerate tails, 3,6, 9,12, 15, 18 and >24 week (fully) old regenerated tails post autotomy (pa). Fully regenerated tails had significantly slower lymph speed, slower radiocolloid migration from injection site, lower lymphatic density and higher diameter of lymphatic vessels, than similar sized geckos with non-regenerate tails. Their comparison to 6-18 week old tails, confirmed no significant difference in lymph speed, radiocolloid migration or diameter of lymphatic vessels. No measurable lymphatic flow was seen at 3 weeks pa. A functional lymphatic network was established in regenerating gecko tails, where a combination of data elude to a critical lymphangiogenesis period during 3-6 weeks post autotomy. Copyright (2002) The Australian and New Zealand Society of Nuclear Medicine Inc

  1. On the Hydrodynamics of Anomalocaris Tail Fins.

    Science.gov (United States)

    Sheppard, K A; Rival, D E; Caron, J-B

    2018-04-25

    Anomalocaris canadensis, a soft-bodied stem-group arthropod from the Burgess Shale, is considered the largest predator of the Cambrian period. Thanks to a series of lateral flexible lobes along its dorso-ventrally compressed body, it is generally regarded as an efficient swimmer, well-adapted to its predatory lifestyle. Previous theoretical hydrodynamic simulations have suggested a possible optimum in swimming performance when the lateral lobes performed as a single undulatory lateral fin, comparable to the pectoral fins in skates and rays. However, the role of the unusual fan-like tail of Anomalocaris has not been previously explored. Swimming efficiency and maneuverability deduced from direct hydrodynamic analysis are here studied in a towing tank facility using a three-vane physical model designed as an abstraction of the tail fin. Through direct force measurements, it was found that the model exhibited a region of steady-state lift and drag enhancement at angles of attack greater than 25° when compared to a triangular-shaped reference model. This would suggest that the resultant normal force on the tail fin of Anomalocaris made it well-suited for turning maneuvers, giving it the ability to turn quickly and through small radii of curvature. These results are consistent with an active predatory lifestyle, although detailed kinematic studies integrating the full organism, including the lateral lobes, would be required to test the effect of the tail fin on overall swimming performance. This study also highlights a possible example of evolutionary convergence between the tails of Anomalocaris and birds, which, in both cases, are well-adapted to efficient turning maneuvers.

  2. 10 CFR 40.2a - Coverage of inactive tailings sites.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Coverage of inactive tailings sites. 40.2a Section 40.2a... Coverage of inactive tailings sites. (a) Prior to the completion of the remedial action, the Commission..., if the site is covered by the remedial action program of title I of the Uranium Mill Tailings...

  3. Uranium Mill Tailings Remedial Action Project surface project management plan

    International Nuclear Information System (INIS)

    1994-09-01

    This Project Management Plan describes the planning, systems, and organization that shall be used to manage the Uranium Mill Tailings Remedial Action Project (UMTRA). US DOE is authorized to stabilize and control surface tailings and ground water contamination at 24 inactive uranium processing sites and associated vicinity properties containing uranium mill tailings and related residual radioactive materials

  4. Containment systems for uranium-mill tailings

    International Nuclear Information System (INIS)

    Hartley, J.N.; Buelt, J.L.

    1982-11-01

    Cover and liner systems for uranium mill tailings in the United States must satisfy stringent requirements regarding long-term stability, radon control, and radionuclide and hazardous chemical migration. The cover and liner technology discussed in this paper involves: (1) single and multilayer earthen cover systems; (2) asphalt emulsion radon barrier systems; and (3) asphalt, clay, and synthetic liner systems. These systems have been field tested at the Grand Junction, Colorado, tailings pile, where they have been shown to effectively reduce radon releases and radionuclide and chemical migration

  5. Growth of soil algae and cyanobacteria on gold mine tailings material

    Directory of Open Access Journals (Sweden)

    Tanya Seiderer

    2017-11-01

    Full Text Available The goal of revegetation of gold mine tailings storage facilities is to reduce aeolian pollution, nutrient leaching and erosion caused by exposure to wind and water. The establishment of biological soil crusts may prove to be a more cost-effective way to reach the same goal and the aim of this study was therefore to determine if it is possible to establish algae and cyanobacteria on gold mine tailings. Different treatments of Chlamydomonas, Microcoleus and Nostoc were inoculated on gold mine tailings in controlled conditions and algal growth was measured on all of the treatments after 6 weeks. Nostoc treatments had the highest chlorophyll-a concentrations and produced a surface crust, while Chlamydomonas treatments penetrated the tailings material and provided the strongest crust. The results were promising but more research is necessary to determine the best organism, or combination of organisms, to colonise mine tailings and to eventually produce biological crusts. Significance: Determination of the best organisms to colonise mine tailings and to produce biological crusts for the revegetation of gold mine tailings storage facilities.

  6. Can tail damage outbreaks in the pig be predicted by behavioural change?

    DEFF Research Database (Denmark)

    Larsen, Mona Lilian Vestbjerg; Andersen, Heidi Mai-Lis; Pedersen, Lene Juul

    2016-01-01

    preventive methods. One strategy is the surveillance of the pigs' behaviour for known preceding indicators of tail damage, which makes it possible to predict a tail damage outbreak and prevent it in proper time. This review discusses the existing literature on behavioural changes observed prior to a tail...... damage outbreak. Behaviours found to change prior to an outbreak include increased activity level, increased performance of enrichment object manipulation, and a changed proportion of tail posture with more tails between the legs. Monitoring these types of behaviours is also discussed for the purpose......, starting with the description of the temporal development of the predictive behaviour in relation to tail damage outbreaks...

  7. Long-term stabilization of uranium mill tailings

    International Nuclear Information System (INIS)

    Voorhees, L.D.; Sale, M.J.; Webb, J.W.; Mulholland, P.J.

    1984-01-01

    The primary hazard associated with uranium mill tailings is exposure to a radioactive gas, radon-222, the concentration of which has been correlated with the occurrence of lung cancer. Previous studies on radon attenuation conclude that the placement of earthen cover materials over the tailings is the most effective technique for reducing radioactive emissions and dispersal of tailings. The success of such a plan, however, is dependent on ensuring the long-term integrity of these cover materials. Soil erosion from water and wind is the major natural cause of destabilizing earthen cover materials. Field data related to the control of soil loss are limited and only indirectly apply to the problem of isolation of uranium mill tailings over very long time periods (up to 80,000 a). However, sufficient information is available to determine benefits that will result from changes in specific design variables and to evaluate the need for different design strategies among potential disposal sites. The three major options available for stabilization of uranium mill tailings are (1) rock cover, (2) soil and revegetation, or (3) a combination of both on different portions of the tailings cover. The optimal choice among these alternatives depends on site-specific characteristics such as climate and local geomorphology and soils, and on design variables such as embankment heights and slopes, modification of upstream drainage, and revegetation practices. Generally, geomorphic evidence suggests that use of soil and vegetation alone will not be adequate to reduce erosion on slopes greater than about 5 to 9%. For these steeper slopes, the use of rock talus or riprap will be necessary to maximize the probability of long-term stability. The use of vegetation to control erosion on the flatter portions of the site may be practicable in regions of the USA with sufficient rainfall and suitable soil types, but revegetation practices must be carefully evaluated to ensure that long

  8. Research on the characterization and conditioning of uranium mill tailings. II. Thermal stabilization of uranium mill tailings: technical and economic evaluation. Volume 2

    International Nuclear Information System (INIS)

    Dreesen, D.R.; Cokal, E.J.; Thode, E.F.; Wangen, L.E.; Williams, J.M.

    1983-06-01

    A method of conditioning uranium mill tailings has been devised to greatly reduce radon emanation and contaminant leachability by using high-temperature treatments, i.e., thermal stabilization. The thermally stabilized products appear resistant to weathering as measured by the effects of grinding and water leaching. The technical feasibility of the process has been partially verified in pilot-scale experiments. A conceptual thermal stabilization process has been designed and the economics of the process show that the thermal stabilization of tailings can be cost competitive compared with relocation of tailings during remedial action. The alteration of morphology, structure, and composition during thermal treatment would indicate that this stabilization method may be a long-lasting solution to uranium mill tailings disposal problems

  9. Postsacral vertebral morphology in relation to tail length among primates and other mammals.

    Science.gov (United States)

    Russo, Gabrielle A

    2015-02-01

    Tail reduction/loss independently evolved in a number of mammalian lineages, including hominoid primates. One prerequisite to appropriately contextualizing its occurrence and understanding its significance is the ability to track evolutionary changes in tail length throughout the fossil record. However, to date, the bony correlates of tail length variation among living taxa have not been comprehensively examined. This study quantifies postsacral vertebral morphology among living primates and other mammals known to differ in relative tail length (RTL). Linear and angular measurements with known biomechanical significance were collected on the first, mid-, and transition proximal postsacral vertebrae, and their relationship with RTL was assessed using phylogenetic generalized least-squares regression methods. Compared to shorter-tailed primates, longer-tailed primates possess a greater number of postsacral vertebral features associated with increased proximal tail flexibility (e.g., craniocaudally longer vertebral bodies), increased intervertebral body joint range of motion (e.g., more circularly shaped cranial articular surfaces), and increased leverage of tail musculature (e.g., longer spinous processes). These observations are corroborated by the comparative mammalian sample, which shows that distantly related short-tailed (e.g., Phascolarctos, Lynx) and long-tailed (e.g., Dendrolagus, Acinonyx) nonprimate mammals morphologically converge with short-tailed (e.g., Macaca tonkeana) and long-tailed (e.g., Macaca fascicularis) primates, respectively. Multivariate models demonstrate that the variables examined account for 70% (all mammals) to 94% (only primates) of the variance in RTL. Results of this study may be used to infer the tail lengths of extinct primates and other mammals, thereby improving our understanding about the evolution of tail reduction/loss. © 2014 Wiley Periodicals, Inc.

  10. Spectral induced polarization (SIP) response of mine tailings.

    Science.gov (United States)

    Placencia-Gómez, Edmundo; Parviainen, Annika; Slater, Lee; Leveinen, Jussi

    2015-02-01

    Mine tailings impoundments are a source of leachates known as acid mine drainage (AMD) which can pose a contamination risk for surrounding surface and groundwater. Methodologies which can help management of this environmental issue are needed. We carried out a laboratory study of the spectral induced polarization (SIP) response of tailings from the Haveri Au-Cu mine, SW Finland. The primary objectives were, (1) to determine possible correlations between SIP parameters and textural properties associated with oxidative-weathering mechanisms, mineralogical composition and metallic content, and (2) to evaluate the effects of the pore water chemistry on SIP parameters associated with redox-inactive and redox-active electrolytes varying in molar concentration, conductivity and pH. The Haveri tailings exhibit well defined relaxation spectra between 100 and 10,000Hz. The relaxation magnitudes are governed by the in-situ oxidative-weathering conditions on sulphide mineral surfaces contained in the tailings, and decrease with the oxidation degree. The oxidation-driven textural variation in the tailings results in changes to the frequency peak of the phase angle, the imaginary conductivity and chargeability, when plotted versus the pore water conductivity. In contrast, the real and the formation electrical conductivity components show a single linear dependence on the pore water conductivity. The increase of the pore water conductivity (dominated by the increase of ions concentration in solution) along with a transition to acidic conditions shifts the polarization peak towards higher frequencies. These findings show the unique sensitivity of the SIP method to potentially discriminate AMD discharges from reactive oxidation zones in tailings, suggesting a significant advantage for monitoring threatened aquifers. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Comparing Phlebotomy by Tail Tip Amputation, Facial Vein Puncture, and Tail Vein Incision in C57BL/6 Mice by Using Physiologic and Behavioral Metrics of Pain and Distress.

    Science.gov (United States)

    Moore, Elizabeth S; Cleland, Thomas A; Williams, Wendy O; Peterson, Christine M; Singh, Bhupinder; Southard, Teresa L; Pasch, Bret; Labitt, Rachael N; Daugherity, Erin K

    2017-05-01

    Tail tip amputation with minimal restraint is not widely used for mouse phlebotomy. In part, this infrequency may reflect policies influenced by tail tip amputation procedures for genotyping, which involve greater handling and tissue removal. To assess tail tip amputation with minimal restraint as a phlebotomy technique, we compared it with 2 more common methods: scruffing with facial vein puncture and lateral tail vein incision with minimal restraint. Blood glucose levels, audible and ultrasonic vocalizations, postphlebotomy activity and grooming behavior, open field and elevated plus maze behaviors, nest-building scores, and histologic changes at the phlebotomy site were evaluated. Mice in the facial vein phlebotomy group produced more audible vocalizations, exhibited lower postphlebotomy activity in the open field, and had more severe histologic changes than did mice in the tail incision and tail tip amputation groups. Facial vein phlebotomy did not affect grooming behavior relative to sham groups, whereas tail vein incision-but not tail tip amputation-increased tail grooming compared with that in control mice. Blood glucose levels, nest-building scores, and elevated plus maze behavior did not differ between groups, and no mice in any group produced ultrasonic vocalizations. Tail tip amputation mice did not perform differently than sham mice in any metric analyzed, indicating that this technique is a potentially superior method of blood collection in mice in terms of animal wellbeing.

  12. Influence of Amang (Tin Tailing) on Geotechnical Properties of Clay Soil

    International Nuclear Information System (INIS)

    Zulfahmi, A.R.; Zuhairi, W.Y.W.; Raihan, M.T.; Sahibin, A.R.; Razi, I.W.M.; Tukimat, L.; Syakireen, Z.S.N.; Noorulakma, A.

    2012-01-01

    Amang or tin tailing is commonly found in the vicinity of disused mining area and responsible in downgrading the water quality, landscape and mechanical behaviour of soils. It was generated from extraction process of separating valuable metal from particular ore. This paper presents the geotechnical characteristics of amang-contaminated clay soil. The geotechnical properties of uncontaminated soils were studied in order to compare to that of amang contaminated soils. The base soil used in this study represents completely weathered horizon of meta sedimentary rock. Meanwhile, tin tailing sample was taken from the disused mine at Sungai Lembing, Pahang. The geotechnical characterisations of base soil and contaminated soils were determined based on consistency index, compaction behaviour, hydraulic conductivity and undrained shear strength (UU tests). Contaminated soil samples were prepared by adding 5, 10 and 20 % of tailing, based on dry weigh of the studied base soil. The results from the particle size distribution analysis showed that residual soil from meta sedimentary rock comprised 42.6 % clay, 32.2 % silt and 25.2 % sand whilst tailing was dominated by 98 % of sand fraction. XRD analysis indicated the presence of quartz, kaolinite and muscovite minerals in the studied soil. The specific gravity of soil used is 2.67 and the pH is 3.88. Tailing found to have higher specific gravity of 3.37. The consistency index of contaminated soils showed that liquid limit, wL and plastic limit, wP decreased with the increase in the percentage of tailing added to the soil samples. The value of maximum dry density, ρ dry max increased while optimum moisture content decreased due to the increase in tailing content in soil sample. The permeability of contaminated soil also increased with the increase in tailing contents ranged from 19.8 cm/ hr to 23.8 cm/ hr. The undrained shear strength, Cu, of contaminated soil decreased from 646 kPa (5 % of tailing) to 312 kPa (20 % of

  13. Effects of submarine mine tailings on macrobenthic community structure and ecosystem processes.

    Science.gov (United States)

    Trannum, Hilde C; Gundersen, Hege; Escudero-Oñate, Carlos; Johansen, Joachim T; Schaanning, Morten T

    2018-07-15

    A mesocosm experiment with intact benthic communities was conducted to evaluate the effects of mine tailings on benthic community structure and biogeochemical processes. Two types of tailings were supplied from process plants using flotation and flocculation chemicals, while a third type was absent of added chemicals. All tailings impacted the sediment community at thin layers, and through more mechanisms than merely hypersedimentation. In general, the strongest impact was observed in a very fine-grained tailings containing flotation chemicals. The second strongest occurred in tailings with no process chemicals. The tailings with flocculation chemicals initiated the weakest response. Fluxes of oxygen, nitrate and ammonium provided some indications on biodegradation of organic phases. Release of phosphate and silicate decreased with increasing layer thickness of all three tailings. A threshold level of 2cm was identified both for faunal responses and for fluxes of phosphate and silicate. The particular impact mechanisms should receive more attention in future studies in order to minimize the environmental risk associated with tailings disposal. Copyright © 2018 Elsevier B.V. All rights reserved.

  14. Putting tailings in perspective radiologically, environmentally and managerially

    International Nuclear Information System (INIS)

    Shreve, J.D. Jr.

    1978-01-01

    Present management of uranium mill tailings is sophisticated compared with recounted practises of 15 to 20 years ago. Further improvements while possible and wanted should not be rushed. Many factors enter. The paper suggests routes to selecting radiological protective standards, elucidates the site-specific and process-specific nature of tailings control, provides comparative references on source terms of radon, uranium, thorium and radium, defends the need for multiple control and for plan endorsement in perpetuity once approval is granted, except as improved control at lesser cost proves doable. One idea is proffered for reducing tailings mass to one-third that accumulated by current practises

  15. Large-scale interaction of the solar wind with cometary plasma tails

    International Nuclear Information System (INIS)

    Niedner, M.B. Jr.

    1979-01-01

    The study of the behavior of plasma tails in the context of their interaction with the solar wind could have important implications for the structure of the interplanetary medium in three dimensions. Comet Kohoutek 1973f exhibited a broad range of plasma tail behavior. On 1974 January 20, the tail was in a highly disturbed condition. Comet Kohoutek was encountering the leading edge of a very strong high-speed stream at the time the plasma tail disturbance started to develop. Comparison of the observed tail geometry on January 20 with the theoretical position angles generated from the wind sock theory of plasma tails and the corotated satellite observations shows that the tail disturbance was probably caused by large gradients of the polar component of the solar-wind velocity. Within hours after the disturbance of January 20, the plasma tail of comet Kohoutek became disconnected from the cometary head, and was replaced by a new plasma tail. The comet was very near an interplanetary sector boundary at the time of disconnection. The disconnection event (DE) is suggested to have resulted from the magnetic reconnection of plasma tail field lines. A similar analysis of other DEs found in original plate material and in published photographs shows the most DEs occur near corotated sector boundaries. Thus, the sector boundary model is further supported, and the finding provides the only known method of probing sector structure to high latitudes. Sector boundaries can often extend to high latitudes in a nearly North-South orientation, and this property is not restricted to times away from solar minimum. Furthermore, the boundaries are inferred to be randomly tilted with respect to the polarity sequence across the boundary and to the magnetic signs of the solar poles

  16. Report of the National Technical Planning Group on Uranium Tailings Research

    International Nuclear Information System (INIS)

    Lapp, P.A.

    1981-09-01

    The National Technical Planning Group on Uranium Tailings Research was formed in 1980 to review present activities and plan a research program on the management of wastes after a mine and mill have shut down. At present there are more than 100 million tonnes of uranium tailings on the surface in Canada. Most of these are under management; however, some 8 million tonnes have been abandoned completely. The group concluded that: 1) there has been no systematic attempt to collect and organize the results of measurements already made on tailings; 2) there is an inadequate understanding of the processes that take place in tailings and in the pathways to the biosphere; 3) there is insufficient evidence on the extent of the long-term problem in the closeout of a uranium tailings basin; 4) there is a need to establish standardized measurement methodologies to improve the quality of data taken at different sites across Canada; 5) generic research and development on tailings disposal technology should be within the scope of a national program, whereas site-specific work is the purview of the mines and regulatory agencies; and 6) the uranium producers' contribution to the national tailings program should be their research on site-specific disposal alternatives. The first of these conclusions leads to the proposal to establish a national uranium tailings research program. The second suggests the need for a modelling program, the third and fourth for a national measurement program, and the remaining conclusions refer to disposal technologies research. The conclusions form the basis for a set of recommendations on uranium tailings research

  17. Geochemical behavior of uranium mill tailings leachate in the subsurface

    International Nuclear Information System (INIS)

    Brookins, D.G.

    1993-01-01

    Leachate generated from surface disposal of acidic uranium mill tailings at Maybell, CO has impacted groundwater quality within the underlying mineralized Browns Park Formation. The extent of groundwater contamination, however, is located directly beneath the tailings impoundment. The milling process consisted of sulfuric acid extraction of uranium from the feed ore by a complex chemical leaching and precipitation process. Tailings leachate at the site contains elevated concentrations of Al, As, Cd, Mo, Ni, NO 3 , Se, U, and other solutes. From column leach tests, the concentrations of contaminants within tailings pore fluid are SO 4 >NH 4 >NO 3 >U>Se>Ni>As>Cd at pH 4.0. The carbonate buffering capacity of the tailings subsoil has decreased because of calcite dissolution in the presence of acidic leachate. Groundwater quality data, mineralogical and microbiological studies, and geochemical modeling suggest that As, NO 3 , Se, U and other solutes are being removed from solution through precipitation, adsorption, and denitrification processes under reducing conditions. Presence of hydrogen sulfide, liquid and gaseous hydrocarbons, dissolved organic, and abundant pyrite within the Browns Park Formations have maintained reducing conditions subjacent to the tailings impoundment. Groundwater is in close equilibrium with coffinite and uraninite, the primary U(IV) minerals extracted from the Browns Parks Formation. Denitrifying bacteria identified in this study catalyze redox reactions involving NO 3 . Subsequently, contaminant distributions of NO 3 decrease 1000 times beneath the tailings impoundment. Applying geochemical and biochemical processes occurring at Maybell provides an excellent model for in situ aquifer restoration programs considered at other uranium tailings and heavy-metal-mixed waste contaminated sites. (author) 4 figs., 4 tabs., 27 refs

  18. The Rubber Tail Illusion as Evidence of Body Ownership in Mice.

    Science.gov (United States)

    Wada, Makoto; Takano, Kouji; Ora, Hiroki; Ide, Masakazu; Kansaku, Kenji

    2016-10-26

    The ownership of one's body parts represents a fundamental aspect of self-consciousness. Accumulating empirical evidence supports the existence of this concept in humans and nonhuman primates, but it is unclear whether nonprimate mammals experience similar feelings. Therefore, the present study used rubber tails to investigate body ownership in rodents. When the real tails and rubber tails were synchronously stroked, the mice responded as if their own tails were touched when the rubber tails were grasped. In contrast, when the stimuli were delivered asynchronously, there was a significantly lower mean response rate when the rubber tail was grasped. These findings suggest that mice may experience body ownership of their tails, suggestive of the rubber hand illusion in humans. To explore the manner in which the ownership of body parts is experienced, this study specifically used the rubber hand illusion (RHI), in which self-consciousness can be extended out of one's own body. Accumulating empirical evidence supports the existence of this concept in humans and nonhuman primates, but it remains unclear whether nonprimate mammals experience similar feelings. This study demonstrated for the first time that mice may experience body ownership of their tails, which is suggestive of the RHI in humans and provides evidence that may highlight how humans experience the ownership of body parts. Copyright © 2016 the authors 0270-6474/16/3611133-05$15.00/0.

  19. Graphite tail powder and liquid biofertilizer as trace elements source for ground nut

    Science.gov (United States)

    Hindersah, Reginawanti; Setiawati, M. Rochimi; Fitriatin, B. Natalie; Suryatama, Pujawati; Asmiran, Priyanka; Panatarani, Camellia; Joni, I. Made

    2018-02-01

    Utilization of graphite tail waste from the mineral beneficiation processing is very important since it contain significant amount of essential minerals which are necessary for plant growth. These mineral are required in biochemical processes and mainly play an important role as cofactor in enzymatic reaction. The objective of this research is to investigate the performance of graphite tail on supporting plant growth and yield of ground nut (Arachishypogeae L.). A field experiment has been performed to test the performance of mixed graphite tail and reduced organic matter dose. The graphite tail size were reduced to various sieved size, -80 mesh, -100 mesh and -200 mesh. The experiment was setup in randomized block design with 4 treatments and 6 replications for each treatment, while the control plot is received without graphite tail. The results demonstrated that reduced organic matter along with -200 mesh tail has potentially decreased plant height at the end of vegetative growth stage, in contrast for to -80 mesh tail amendment increased individual fresh plant biomass. Statistically, there was no change of plant nodule, individual shoot fresh and dry weight, root nodule, number of pod following any mesh of graphite tail amendment. Reducing organic matter while adding graphite tail of 5% did not change bean weight in all plot. In contrast, reduced organic matter along with 80-mesh graphite tail amendment improved the nut yield per plot. This experiment suggests that graphite tail, mainly -80 mesh graphite tail can be possibly used in legume production.

  20. Analytical Solution and Application for One-Dimensional Consolidation of Tailings Dam

    OpenAIRE

    Liu, Hai-ming; Nan, Gan; Guo, Wei; Yang, Chun-he; Zhang, Chao

    2018-01-01

    The pore water pressure of tailings dam has a very great influence on the stability of tailings dam. Based on the assumption of one-dimensional consolidation and small strain, the partial differential equation of pore water pressure is deduced. The obtained differential equation can be simplified based on the parameters which are constants. According to the characteristics of the tailings dam, the pore water pressure of the tailings dam can be divided into the slope dam segment, dry beach seg...