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Sample records for tailings impoundment dneprodzerzhynsk

  1. 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

  2. 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

  3. A generic model of contaminant migration from uranium tailings impoundments

    International Nuclear Information System (INIS)

    Shepherd, T.A.; Brown, S.E.

    1982-01-01

    This paper presents an analytical hydrogeochemical model based upon acid consumption-neutralization front movement. The development of contaminant plumes is discussed and distinct zones within these plumes are identified and characterized. The most important process influencing the rate and extent of contaminant migration at acid-leach uranium tailings impoundments is the neutralization of seepage water by soils along ground water flow paths. The chemical characteristics of the ground water is determined in order to identify and characterize zones within migrating plumes of tailings-derived water. It is concluded that the characterization of specific zones is useful in the interpretation of existing conditions, in the evaluation of future migration, and in the determination of appropriate models for the specific situation

  4. Design, permitting, and construction issues associated with closure of the Panna Maria uranium tailings impoundment

    International Nuclear Information System (INIS)

    Strachan, C.L.; Raabe, K.L.

    1997-01-01

    In 1992, Panna Maria Uranium Operations (PMUO) initiated licensing and engineering activities for closure of the Panna Maria mill and 150-acre tailings impoundment located in southeast Texas. Closure of the tailings impoundment is permitted by license amendment through the Texas Natural Resources Conservation Commission (TNRCC), and based on closure criteria outlined in Texas regulations. The closure plan for the Panna Maria tailings impoundment was submitted for Texas regulatory agency review in April 1993, with details of the closure plan modified in 1994, 1995, and 1996. The closure plan included a multi-layered cover over the regraded tailings surface which was designed for long-term isolation of tailings, reduction of radon emanation to regulated levels, and reduction of infiltration to TNRCC-accepted levels. The cover and embankment slope surfaces and surrounding areas were designed to provide acceptable erosional stability as compared to runoff velocities from the Probable Maximum Precipitation event. Cover materials were selected from on-site materials and evaluated for suitability based on permeability, radon attenuation, and soil dispersivity characteristics. Off-site materials were used when necessary. The cover over the tailings has a maximum slope of 0.5 percent, and the regraded embankment slopes outside the perimeter of the impoundment have a maximum slope of 20 percent. All reclaimed slopes are covered with topsoil and revegetated. A riprap-lined channel is to be used to convey runoff from within the perimeter of the reclaimed impoundment to the north of the impoundment

  5. UAV Remote Sensing Surveillance of a Mine Tailings Impoundment in Sub-Arctic Conditions

    Directory of Open Access Journals (Sweden)

    Anssi Rauhala

    2017-12-01

    Full Text Available Mining typically involves extensive areas where environmental monitoring is spatially sporadic. New remote sensing techniques and platforms such as Structure from Motion (SfM and unmanned aerial vehicles (UAVs may offer one solution for more comprehensive and spatially continuous measurements. We conducted UAV campaigns in three consecutive summers (2015–2017 at a sub-Arctic mining site where production was temporarily suspended. The aim was to monitor a 0.5 km2 tailings impoundment and measure potential subsidence of tailings. SfM photogrammetry was used to produce yearly topographical models of the tailings surface, which allowed the amount of surface displacement between years to be tracked. Ground checkpoints surveyed in stable areas of the impoundment were utilized in assessing the vertical accuracy of the models. Observed surface displacements were linked to a combination of erosion, tailings settlement, and possible compaction of the peat layer underlying the tailings. The accuracy obtained indicated that UAV-assisted monitoring of tailings impoundments is sufficiently accurate for supporting impoundment management operations and for tracking surface displacements in the decimeter range.

  6. Methodologies for evaluating long-term stabilization designs of uranium mill tailings impoundments

    International Nuclear Information System (INIS)

    Nelson, J.D.; Abt, S.R.; Volpe, R.L.; Van Zye, D.; Hinkle, N.E.; Staub, W.P.

    1986-06-01

    Uranium mill tailings impoundments require long-term (200 to 1000 years) stabilization. This report reviews currently available methodologies for evaluating factors that can have a significant influence on tailings stabilization and develops methodologies in technical areas where none presently exist. Mill operators can use these methodologies to assist with (1) the selection of sites for mill tailings impoundments, (2) the design of stable impoundments, and (3) the development of reclamation plans for existing impoundments. These methodologies would also be useful for regulatory agency evaluations of proposals in permit or license applications. Methodologies were reviewed or developed in the following technical areas: (1) prediction of the Probable Maximum Precipitation (PMP) and an accompanying Probable Maximum Flood (PMF); (2) prediction of the stability of local and regional fluvial systems; (3) design of impoundment surfaces resistant to gully erosion; (4) evaluation of the potential for surface sheet erosion; (5) design of riprap for protecting embankments from channel flood flow and overland flow; (6) selection of riprap with appropriate durability for its intended use; and (7) evaluation of oversizing required for marginal quality riprap

  7. Analysis of spatial distribution and inventory of radioactivity within the uranium mill tailings impoundment

    OpenAIRE

    D. O. Bugai; G. V. Laptev; O. S. Skalskyy; T. V. Lavrova; R. Avila

    2015-01-01

    Results are presented of the characterization of radioactivity inventory of Zapadnoe uranium mill tailings impoundment situated at Pridneprovsky Chemical Plant (PChP; Dneprodzerzhinsk, Ukraine). Analyses of radioactivity data set based on analytical studies of core material from 15 characterization boreholes allowed significantly refining waste volume and radioactivity inventory estimates. Geostatistical analyses using variogram function have established that radioactivity distribution in Zap...

  8. Dose assessment of remedial action for uranium tailing impoundment of a nuclear factory

    International Nuclear Information System (INIS)

    Li Xutong; Ma Ruwei; Guo Zede

    2000-01-01

    A large uranium tailing impoundment in China will be closure and remedial action have been planned. The remedial action will include shaping and covering the dam and beach in order to prevent the impoundment from damage and restrict spread of tailing sands and emission of radon. The author presents the analysis and estimation of the exposure to workers for remedial action and to public after the remedial action. To estimate the exposure to workers, the pathway of inhalation of radon, tailing sands in suspension and external γ exposure were taken into consideration. The exposure scenario is considered as probably maximum exposure to the workers who work on the tailing pile without any protection measures, the dose is 6.0 mSv/a. Two situation for the exposure to public after remedial action were considered: normal and abnormal condition. For the normal condition, inhalation of radon emitted from impoundment is only the pathway to public for the exposure, and individual dose for critical group of public is 0.053 mSv/a, collective dose for population within 80 km is 1.0 man·Sv/a. For the abnormal conditions, four scenarios were considered, i.e. dwelling on tailing pile, farming on tailing pile, living in a house built by contaminated materials and some temporal activities on the pile. The scenarios of dwellings is living in a house on the pile and drinking contaminated water. The maximum individual dose is 27 mSv/a

  9. 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

  10. Development of a dust deposition forecast model for a mine tailings impoundment

    Science.gov (United States)

    Stovern, Michael

    Wind erosion, transport and deposition of particulate matter can have significant impacts on the environment. It is observed that about 40% of the global land area and 30% of the earth's population lives in semiarid environments which are especially susceptible to wind erosion and airborne transport of contaminants. With the increased desertification caused by land use changes, anthropogenic activities and projected climate change impacts windblown dust will likely become more significant. An important anthropogenic source of windblown dust in this region is associated with mining operations including tailings impoundments. Tailings are especially susceptible to erosion due to their fine grain composition, lack of vegetative coverage and high height compared to the surrounding topography. This study is focused on emissions, dispersion and deposition of windblown dust from the Iron King mine tailings in Dewey-Humboldt, Arizona, a Superfund site. The tailings impoundment is heavily contaminated with lead and arsenic and is located directly adjacent to the town of Dewey-Humboldt. The study includes in situ field measurements, computational fluid dynamic modeling and the development of a windblown dust deposition forecasting model that predicts deposition patterns of dust originating from the tailings impoundment. Two instrumented eddy flux towers were setup on the tailings impoundment to monitor the aeolian and meteorological conditions. The in situ observations were used in conjunction with a computational fluid dynamic (CFD) model to simulate the transport of windblown dust from the mine tailings to the surrounding region. The CFD model simulations include gaseous plume dispersion to simulate the transport of the fine aerosols, while individual particle transport was used to track the trajectories of larger particles and to monitor their deposition locations. The CFD simulations were used to estimate deposition of tailings dust and identify topographic mechanisms

  11. Rock riprap design methods and their applicability to long-term protection of uranium mill tailings impoundments

    International Nuclear Information System (INIS)

    Walters, W.H.

    1982-08-01

    This report reviews the more accepted or recommended riprap design methods currently used to design rock riprap protection against soil erosion by flowing water. The basic theories used to develop the various methods are presented. The Riprap Design with Safety Factors Method is identified as the logical choice for uranium mill tailings impoundments. This method is compared to the other methods and its applicability to the protection requirements of tailings impoundments is discussed. Other design problems are identified and investigative studies recommended

  12. 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.

    1986-01-01

    This paper presents a program of current and future research into those geomorphological processes likely to affect the long term containment of uranium mill tailings in the Alligator Rivers Region of the Northern Territory. Research 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

  13. Analysis of spatial distribution and inventory of radioactivity within the uranium mill tailings impoundment

    Directory of Open Access Journals (Sweden)

    D. O. Bugai

    2015-10-01

    Full Text Available Results are presented of the characterization of radioactivity inventory of Zapadnoe uranium mill tailings impoundment situated at Pridneprovsky Chemical Plant (PChP; Dneprodzerzhinsk, Ukraine. Analyses of radioactivity data set based on analytical studies of core material from 15 characterization boreholes allowed significantly refining waste volume and radioactivity inventory estimates. Geostatistical analyses using variogram function have established that radioactivity distribution in Zapadnoe tailings is characterized by regular spatial correlation patterns. Ordinary kriging method was applied to assess distribution of radioactivity in 3D. Results of statistical analyses suggest significant redistribution of uranium in the dissolved form in the residues (presumably due to water infiltration process. The developed structural model for radioactivity distribution is used for further risk assessment analyses. Derived radioactivity correlation scales can be used for optimization of sample collection when characterizing the PChP Site and similar contaminated sites elsewhere.

  14. 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

  15. Survivability of ancient man-made earthen mounds: implications for uranium mill tailings impoundments

    Energy Technology Data Exchange (ETDEWEB)

    Lindsey, C.G.; Mishima, J.; King, S.E.; Walters, W.H.

    1983-06-01

    As part of a study for the Nuclear Regulatory Commission (NRC), the Pacific Northwest Laboratory (PNL) is investigating long-term stabilization techniques for uranium mill impoundments. Part of this investigation involves the design of a rock armoring blanket (riprap) to mitigate wind and water erosion of the underlying soil cover, which in turn prevents exposure of the tailings to the environment. However, the need for the armoring blanket, as well as the blanket's effectiveness, depends on the stability of the underlying soil cap (radon suppression cover) and on the tailings themselves. Compelling evidence in archaeological records suggests that large man-made earthen structures can remain sound and intact for time periods comparable to those required for the stabilization of the tailings piles if properly constructed. We present archaeological evidence on the existence and survivability of man-made earthen and rock structures through specific examples of such structures from around the world. We also review factors contributing to their survival or destruction and address the influence of climate, building materials, and construction techniques on survivability.

  16. Survivability of ancient man-made earthen mounds: implications for uranium mill tailings impoundments

    International Nuclear Information System (INIS)

    Lindsey, C.G.; Mishima, J.; King, S.E.; Walters, W.H.

    1983-06-01

    As part of a study for the Nuclear Regulatory Commission (NRC), the Pacific Northwest Laboratory (PNL) is investigating long-term stabilization techniques for uranium mill impoundments. Part of this investigation involves the design of a rock armoring blanket (riprap) to mitigate wind and water erosion of the underlying soil cover, which in turn prevents exposure of the tailings to the environment. However, the need for the armoring blanket, as well as the blanket's effectiveness, depends on the stability of the underlying soil cap (radon suppression cover) and on the tailings themselves. Compelling evidence in archaeological records suggests that large man-made earthen structures can remain sound and intact for time periods comparable to those required for the stabilization of the tailings piles if properly constructed. We present archaeological evidence on the existence and survivability of man-made earthen and rock structures through specific examples of such structures from around the world. We also review factors contributing to their survival or destruction and address the influence of climate, building materials, and construction techniques on survivability

  17. Investigation, assessment and remediation of the water pathway in the surroundings of the Culmitzsch A tailings impoundment

    International Nuclear Information System (INIS)

    Schulze, G.; Paul, M.; Priester, J.; Schoepfer, C.

    1998-01-01

    Several large tailings impoundments in Saxony and Thuringia are the result of the extensive uranium mining and milling in Eastern Germany after World War II. The Culmitzsch tailings pond in Eastern Thuringia was constructed within a former uranium open pit mine and is located within the Culmitzsch trench fault. The tailings impoundment includes two ponds (Culmitzsch A and B) which are separated by an internal dam with an impervious core. The Culmitzsch A pond covers an area of 158 ha, the maximum tailings thickness is 70 m. Between this pond (elevation of up to 340 m above sea-level) and the Lerchenbach creek (265.. 280 m above sea-level) a steep gradient exists. So the valley of the Lerchenbach is the general discharge area for the seepage of the pond which is a result of dewatering by gravity and consolidation. The seepage water migrates through the southern dam of the impoundment and through permeable layers which are in contact with the tailings. About 400 groundwater wells were installed within three aquifers in order to clarify the flow direction and the degree of contamination of the groundwater as well as to investigate the geohydraulic properties of the rocks in the surroundings of the pond. Based on the results of this investigation programme a three-dimensional hydrogeological model was built up which reflects the general relationships between the pond and its geological setting as well as the water balance of the whole system. Presently a catchment system exists which gathers all surface waters with significant uranium and salt concentrations. Moreover dewatering wells on the beach zone of the pond and catchment wells in the downstream area of the impoundment have been installed. Before being released to the receiving streams seepage and freewater are treated in a two-step water treatment plant in order to decrease their uranium, radium and arsenic contents. (orig.) [de

  18. Low-level radioactive waste disposal in the USA - Use of mill tailings impoundments as a new policy option

    International Nuclear Information System (INIS)

    Farrell, C.W.

    2006-01-01

    Disposal of low-level radioactive waste (LLW) in the United States is facing severe and immediate capacity limitations. Seemingly intractable regulatory and jurisdictional conflicts make establishment of new LLW disposal sites effectively impossible. Uranium mill tailings impoundments constructed at conventional uranium open-cast and underground mines could offer approximately 40 to 80+ million tons of disposal capacity for low activity radioactive waste. Such impoundments would provide an enhanced, high level of environmental and health and safety protection for the direct disposal of depleted uranium, special nuclear material, technologically-enhanced, naturally-occurring radioactive material (TENORM) and mixed waste. Many waste streams, such as TENORM and decommissioning rubble, will be high-volume, low activity materials and ideally suited for disposal in such structures. Materials in a given decay chain with a total activity from all radionuclides present of ∼820 Bq/g (2.22 x 10 -08 Ci/g) with no single radionuclide present in an activity greater than ∼104 Bq/g (2,800 pCi/g) should be acceptable for disposal. Materials of this type could be accepted without any site-specific dose modelling, so long as the total activity of the tailings impoundment not exceed its design capacity (generally 82 x 10 07 Bq/metric tonne) (0.020 Ci/short ton) and the cover design requirements to limit radon releases are satisfied. This paper provides background on US LLW disposal regulations, examines LLW disposal options under active consideration by the US Environmental Protection Agency and Department of Energy, develops generic waste acceptance criteria and identifies policy needs for federal and state governments to facilitate use of uranium mill tailings impoundments for LLW disposal. (author)

  19. Vegetation composition and 226Ra uptake by native plant species at a uranium mill tailings impoundment in South China

    International Nuclear Information System (INIS)

    Hu, Nan; Ding, Dexin; Li, Guangyue; Zheng, Jifang; Li, Le; Zhao, Weichao; Wang, Yongdong

    2014-01-01

    A field investigation was conducted for the vegetation composition and 226 Ra uptake by native plant species at a uranium mill tailings impoundment in South China. 80 species belonging to 67 genera in 32 families were recorded in the sampling sites. The Poaceae and Asteraceae were the dominant families colonizing the impoundment. The number of the plant species and vegetation community composition in the sampling sites seemed most closely related to the activities of 226 Ra and the pH value of the uranium tailings. The plant species in the sampling sites with relatively low activities of 226 Ra and relatively high pH value formed a relatively stable vegetation community. The plant species in the sampling sites with medium activities of 226 Ra and medium pH value formed the transitional vegetation community. The plant species in the sampling sites with relatively high activities of 226 Ra and relatively low pH value formed a simple unstable vegetation community that was similar to that on the unused grassland. The activities of 226 Ra and transfer factors (TFs) varied greatly with the plant species. The high activities of 226 Ra and TFs were found in the leaves of Pteris multifida (150.6 Bq/g of AW; 9.131), Pteridium aquilinum (122.2 Bq/g of AW; 7.409), and Dryopteris scottii (105.7 Bq/g of AW; 6.408). They satisfied the criteria for a hyperaccumulator for 226 Ra. They may be the candidates for phytoremediation of 226 Ra in the uranium mill tailings impoundment areas and the contaminated soils around. - Highlights: • Vegetation composition of native plant species at an impoundment was analyzed. • 226 Ra uptake by native plant species at the impoundment was investigated. • Poaceae and Asteraceae were the dominated families colonizing this impoundment. • The plant species and composition were related to activities of 226 Ra and pH. • Three plant species were found to be hyperaccumulators for 226 Ra

  20. Microbial communities in a porphyry copper tailings impoundment and their impact on the geochemical dynamics of the mine waste.

    Science.gov (United States)

    Diaby, Nouhou; Dold, Bernhard; Pfeifer, Hans-Rudolf; Holliger, Christof; Johnson, D Barrie; Hallberg, Kevin B

    2007-02-01

    The distribution and diversity of acidophilic bacteria of a tailings impoundment at the La Andina copper mine, Chile, was examined. The tailings have low sulfide (1.7% pyrite equivalent) and carbonate (1.4% calcite equivalent) contents and are stratified into three distinct zones: a surface (0-70-80 cm) 'oxidation zone' characterized by low-pH (2.5-4), a 'neutralization zone' (70-80 to 300-400 cm) and an unaltered 'primary zone' below 400 cm. A combined cultivation-dependent and biomolecular approach (terminal restriction enzyme fragment length polymorphism and 16S rRNA clone library analysis) was used to characterize the indigenous prokaryotic communities in the mine tailings. Total cell counts showed that the microbial biomass was greatest in the top 125 cm of the tailings. The largest numbers of bacteria (10(9) g(-1) dry weight of tailings) were found at the oxidation front (the junction between the oxidation and neutralization zones), where sulfide minerals and oxygen were both present. The dominant iron-/sulfur-oxidizing bacteria identified at the oxidation front included bacteria of the genus Leptospirillum (detected by molecular methods), and Gram-positive iron-oxidizing acidophiles related to Sulfobacillus (identified both by molecular and cultivation methods). Acidithiobacillus ferrooxidans was also detected, albeit in relatively small numbers. Heterotrophic acidophiles related to Acidobacterium capsulatum were found by molecular methods, while another Acidobacterium-like bacterium and an Acidiphilium sp. were isolated from oxidation zone samples. A conceptual model was developed, based on microbiological and geochemical data derived from the tailings, to account for the biogeochemical evolution of the Piuquenes tailings impoundment.

  1. Use of special oedometer tests for the remediation of large uranium mill tailings impoundments at Wismut, Germany

    International Nuclear Information System (INIS)

    Barnekow, U.; Paul, M.

    2002-01-01

    The paper presents the use of recently developed special oedometer tests for designing the remediation of large uranium tailings ponds at WISMUT, Germany. Uranium ore mining and milling in eastern Germany by the former Soviet-German WISMUT company lasted from 1946 to 1990. Wastes from the hydrometallurgical uranium extraction processes were discharged into large tailings impoundments covering a total area of 5.5 km 2 and containing about 150 x 10 6 m 3 of uranium mill tailings. Tailings pond remediation is ongoing by in-place decommissioning with dewatering by technical means. Geotechnical properties and the most suitable so-called non-linear finite strain consolidation behaviour of fine uranium mill tailings are described. Decommissioning techniques comprise, among others, interim covering of under consolidated fine tailings, contouring of tailings surfaces and final covering. Contouring, in particular, has a huge potential for optimization in terms of cost reduction. For contouring total settlement portions, the spatial distribution of differential settlement portions and the time-dependent settlement rates, especially of the cohesive fine uranium mill tailings are of critical importance. A new special oedometer KD 314 S has been developed to generate all the input data needed to derive the fundamental geotechnical relationships of void ratio vs. effective stress and of permeability coefficient vs. void ratio for consolidation calculations. Since December 1999 the new special oedometer KD 314 S has been working successfully on fine uranium mill tailings from both acid and from soda alkaline milling. Results coincide with non-linear finite strain consolidation theory. The geotechnical functions derived were used as input parameters for consolidation modelling. An example of the consolidation modelling on Helmsdorf tailings pond is presented. (author)

  2. 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

  3. Geochemical characterisation of seepage and drainage water quality from two sulphide mine tailings impoundments: Acid mine drainage versus neutral mine drainage

    Science.gov (United States)

    Heikkinen, P.M.; Raisanen, M.L.; Johnson, R.H.

    2009-01-01

    Seepage water and drainage water geochemistry (pH, EC, O2, redox, alkalinity, dissolved cations and trace metals, major anions, total element concentrations) were studied at two active sulphide mine tailings impoundments in Finland (the Hitura Ni mine and Luikonlahti Cu mine/talc processing plant). The data were used to assess the factors influencing tailings seepage quality and to identify constraints for water treatment. Changes in seepage water quality after equilibration with atmospheric conditions were evaluated based on geochemical modelling. At Luikonlahti, annual and seasonal changes were also studied. Seepage quality was largely influenced by the tailings mineralogy, and the serpentine-rich, low sulphide Hitura tailings produced neutral mine drainage with high Ni. In contrast, drainage from the high sulphide, multi-metal tailings of Luikonlahti represented typical acid mine drainage with elevated contents of Zn, Ni, Cu, and Co. Other factors affecting the seepage quality included weathering of the tailings along the seepage flow path, process water input, local hydrological settings, and structural changes in the tailings impoundment. Geochemical modelling showed that pH increased and some heavy metals were adsorbed to Fe precipitates after net alkaline waters equilibrated with the atmosphere. In the net acidic waters, pH decreased and no adsorption occurred. A combination of aerobic and anaerobic treatments is proposed for Hitura seepages to decrease the sulphate and metal loading. For Luikonlahti, prolonged monitoring of the seepage quality is suggested instead of treatment, since the water quality is still adjusting to recent modifications to the tailings impoundment.

  4. DC resistivity and IP methods in acid mine drainage problems: results from the Copper Cliff mine tailings impoundments

    Science.gov (United States)

    Yuval, Douglas; Oldenburg, W.

    1996-04-01

    Oxidation of sulfide minerals in the mine tailings impoundments at Copper Cliff, Ontario generates acidic conditions and elevated concentrations of dissolved metals and sulfates in the pore water. The pore water migrates away from the tailings to pose a potential environmental hazard if is should reach nearby water systems. There is a need to characterize this potential environmental problem and to assess the future hazards. A combined DC resistivity and induced polarization (IP) survey was carried out along one of the major flowpaths in the tailings and the data were inverted to produce detailed electrical conductivity and chargeability structures of the cross-section below the survey line. The conductivity distributions are directly translated, through theoretical and empirical relations, to a map of the concentration of the total dissolved solids (TDS) along the cross-section and thereby provide insight about the in-situ pore water quality. The sulfide minerals are the source of the IP response and, thus, when combined with borehole data, the chargeability model can be used to estimate the amount and distribution of the sulfides.

  5. 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.

  6. Leak detection systems for uranium mill tailings impoundments with synthetic liners

    International Nuclear Information System (INIS)

    Myers, D.A.; Tyler, S.W.; Gutknecht, P.J.; Mitchell, D.H.

    1983-09-01

    This study evaluated the performance of existing and alternative leak detection systems for lined uranium mill tailings ponds. Existing systems for detecting leaks at uranium mill tailings ponds investigated in this study included groundwater monitoring wells, subliner drains, and lysimeters. Three alternative systems which demonstrated the ability to locate leaks in bench-scale tests included moisture blocks, soil moisture probes, and a soil resistivity system. Several other systems in a developmental stage are described. For proper performance of leak detection systems (other than groundwater wells and lysimeters), a subgrade is required which assures lateral dispersion of a leak. Methods to enhance dispersion are discussed. Cost estimates were prepared for groundwater monitoring wells, subliner drain systems, and the three experimental systems. Based on the results of this report, it is suggested that groundwater monitoring systems be used as the primary means of leak detection. However, if a more responsive system is required due to site characteristics and groundwater quality criteria, subliner drains are applicable for ponds with uncovered liners. Leak-locating systems for ponds with covered liners require further development. Other recommendations are discussed in the report

  7. Aquatic impacts of an environmental disaster in a relatively pristine watershed: the breach of the Mount Polley Mine tailings impoundment, British Columbia, Canada

    Science.gov (United States)

    Owens, Philip; Petticrew, Ellen; Albers, Sam

    2015-04-01

    On 4th August 2014, the tailings impoundment of the Mount Polley copper and gold mine in British Columbia failed. Material from the impoundment (surface area = 2.7 km2) flowed into nearby Polley Lake and Hazeltine Creek, before discharging into Quesnel Lake, a large (ca. 100 km long, >500 m deep), relatively pristine lake. Estimates suggest that approximately 25 Mm3 of tailings (water and solids), in addition to eroded soils and surficial materials from Hazeltine Creek, were delivered to Quesnel Lake, raising the lake by 7.7 cm. Much of this material was deposited at the bottom of Quesnel Lake but a large plume of fine-grained sediment (d50 of ca. 1 µm) moved both up-lake towards important salmon spawning areas and down-lake into Quesnel River, which in turn flows into the Fraser River. This movement of the sediment plume is controlled by the physical limnology of the lake, especially seiche events. Samples of lake water and sediment samples taken from the impacted area show elevated levels of metals and other elements, which may have important implications for the ecosystem in this watershed (>11,000 km2). This presentation describes the failure and presents preliminary findings of the aquatic impacts of this environmental disaster.

  8. Sealing layer of fly ashes and sewage sludge and vegetation establishment in treatment of mine tailings impoundments; Flygaska och roetslam som taetskikt vid efterbehandling av sandmagasin med vegetationsetablering

    Energy Technology Data Exchange (ETDEWEB)

    Greger, Maria; Neuschuetz, Clara [Stockholm Univ. (Sweden). Dept. of Botany; Isaksson, Karl-Erik [Boliden Mineral AB (Sweden)

    2006-02-15

    Each year the Swedish mining industry produces 25 Mtonnes of mine tailings that are disposed of in extensive natural impoundments. As this sand, containing more or less sulphide-rich minerals, is penetrated by oxygen and water, it starts weathering resulting in formation of acidic and metal-rich drainage water. To prevent oxygen penetration the mine tailings can be covered with a sealing layer covered with a protective cover that facilitates establishment of vegetation. The aim of this study has been to examine the function of fly ash and sewage sludge in sealing layers at impoundments of pyrite rich mine tailings, and the ability of different plant species, which are suitable for establishment in these areas, to penetrate the sealing layer with their roots and what impact they have on the drainage water. Experiments have been performed in field and greenhouse environment, with sealing layers consisting of fly ash and sewage sludge mixtures, covered with protective covers of sewage sludge or till. Plant establishment has been studied in a survey of naturally established plants at sewage sludge disposal sites close to mining areas, and by sowing and planting of selected plants, for instance fast growing grass species and fibre hemp at the test plots in field and in greenhouse experiments. Large scale application of ashes, sewage sludge and an ash/sludge mixture have been performed in field at three test plots with the size of 0.3-1 ha. Leakage of nutrients and metals from sealing layers has been studied in field and greenhouse tests. In addition, the ability of plant roots to penetrate sealing layers made of different ash/sludge mixtures have been examined in greenhouse experiments. This investigation is a cooperation between Stockholm University and Boliden Mineral AB, and the field experiments have been performed at the mine tailings impoundments at Gillervattnet, Boliden. Other collaborating participants are Skellefteaa Kraft and Munksund, who have produced the

  9. Influence of vegetation and sewage sludge on sealing layer of fly ashes in post-treatment of mine tailings impoundments; Inverkan av vegetation och roetslam paa taetskikt av flygaska vid efterbehandling av sandmagasin

    Energy Technology Data Exchange (ETDEWEB)

    Greger, Maria; Neuschuetz, Clara (Inst. of Bothany, Stockholm Univ., Stockholm (Sweden)); Isaksson, Karl-Erik (Boliden Mineral AB, Stockholm (Sweden))

    2009-03-15

    Mining industry produces 25 Mton mine tailings yearly that are deposited in impoundments in the nature. When this sand, containing sulphur rich minerals, reacts with oxygen and water it starts to weather and acidic metal rich water is formed. To prevent this, the sand can be covered with a sealing layer and a protective cover layer with vegetation. As sealing and cover materials fly ashes and sewage sludge can be used. The aim of this investigation was to find out: 1) how sealing layer of fly ashes with and without sewage sludge, and a cover with sewage sludge can be placed practically on mine tailings in a cold climate. 2) how such a cover should be constructed to minimize the risk of root penetration and leakage of nutrients and metals 3) which vegetation that is most suitable This was investigated in field- and greenhouse tests with a sealing layer of fly ash and/or sewage sludge with a cover layer of sewage sludge in which different plant species were established. The practical application was performed in 0.3-1 ha plots at a mine tailings impoundments at Boliden. The ability of plant roots to penetrate a sealing layer was investigated, as well as the effect of simulated root exudates on the penetration resistance in hardened ash. Leakage of nutrients and metals from cover layer of sewage sludge, in some cases with sealing layers beneath, was investigated in field and greenhouse lysimeters. Various plant species were compared on their ability to affect metal and nutrient leakage as well as root penetration and shattering of the hardened ashes. The project was a cooperation between Stockholm University and Boliden Mineral AB, and the field tests were performed at the impoundment Gillervattnet in Boliden and in Garpenberg. Cooperating were also Iggesund Paperboard, Skellefteaa Kraft, Stora Enso Fors, Umeaa Energi and Vattenfall, all producers of ashes that were used, as well as Stockholm Vatten AB, which produced the sewage sludge. The most important conclusions

  10. River impoundment and sunfish growth

    Science.gov (United States)

    Andrew L. Rypel

    2011-01-01

    Impoundment of rivers by dams is widespread and one of the most devastating anthropogenic impacts to freshwater environments. Linking theoretical and applied research on river impoundment requires an improved capacity for predicting how varying degrees of impoundment affects a range of species. Here, growth of 14 North American sunfish species resilient to river...

  11. 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 ...

  12. Leachability of metals from gold tailings by rainwater: an ...

    African Journals Online (AJOL)

    2016-01-01

    Jan 1, 2016 ... ABSTRACT. 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 ...

  13. Electrodialytic remediation of copper mine tailings

    DEFF Research Database (Denmark)

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

    2005-01-01

    Mining activities in Chile have generated large amounts of solid waste, which have been deposited in mine tailing impoundments. These impoundments cause concern to the communities due to dam failures or natural leaching to groundwater and rivers.This work shows the laboratory results of nine...... 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......, and the copper by this reason was released in the solution. Furthermore, with acidic tailing the potential gradient was less than 2V/cm.The maximum copper removal reached in the anode side was 53% with addition of sulphuric acid in 21 days experiment at 20V using approximately 1.8kg mine tailing on dry basis...

  14. 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)

  15. Surface mine impoundments as wildlife and fish habitat

    Science.gov (United States)

    Mark A. Rumble

    1989-01-01

    Unreclaimed surface mine impoundments provide poor fish and wildlife habitat. Recommendations given here for reclaiming "prelaw" impoundments and creating new impoundments could provide valuable fish and wildlife habitat if incorporated into existing laws and mine plans.

  16. 50 CFR 28.42 - Impounding of domestic animals.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 6 2010-10-01 2010-10-01 false Impounding of domestic animals. 28.42... VIOLATIONS OF PARTS 25, 26, AND 27 Impoundment Procedures § 28.42 Impounding of domestic animals. (a) Any animal trespassing on the lands of any national wildlife refuge may be impounded and disposed of in...

  17. Field evaporation test of uranium tailings solution

    International Nuclear Information System (INIS)

    Chandler, B.L.; Shepard, T.A.; Stewart, T.A.

    1985-01-01

    A field experiment was performed to observe the effect on evaporation rate of a uranium tailings impoundment pond water as salt concentration of the water increased. The duration of the experiment was long enough to cause maximum salt concentration of the water to be attained. The solution used in the experiment was tailings pond water from an inactive uranium tailings disposal site in the initial stages of reclamation. The solution was not neutralized. The initial pH was about 1.0 decreasing to a salt gel at the end of the test. The results of the field experiment show a gradual and slight decrease in evaporation efficiency. This resulted as salt concentrations increased and verified the practical effectiveness of evaporation as a water removal method. In addition, the physical and chemical nature of the residual salts suggest that no long-term stability problem would likely result due to their presence in the impoundment during or after reclamation

  18. Accelerated aging tests of liners for uranium mill tailings disposal

    International Nuclear Information System (INIS)

    Barnes, S.M.; Buelt, J.L.; Hale, V.Q.

    1981-11-01

    This document describes the results of accelerated aging tests to determine the long-term effectiveness of selected impoundment liner materials in a uranium mill tailings environment. The study was sponsored by the US Department of Energy under the Uranium Mill Tailings Remedial Action Project. The study was designed to evaluate the need for, and the performance of, several candidate liners for isolating mill tailings leachate in conformance with proposed Environmental Protection Agency and Nuclear Regulatory Commission requirements. The liners were subjected to conditions known to accelerate the degradation mechanisms of the various liners. Also, a test environment was maintained that modeled the expected conditions at a mill tailings impoundment, including ground subsidence and the weight loading of tailings on the liners. A comparison of installation costs was also performed for the candidate liners. The laboratory testing and cost information prompted the selection of a catalytic airblown asphalt membrane and a sodium bentonite-amended soil for fiscal year 1981 field testing

  19. Estimates of population distributions and tailings areas around licensed uranium mill sites. Final report

    International Nuclear Information System (INIS)

    Hans, J.M.; Hall, J.B.; Moore, W.E.

    1986-08-01

    Population distributions and tailings areas were estimated from aerial photography for each of 21 licensed uranium millsites. Approximately 11,600 persons live within 5 kilometers of the tailings impoundments at the millsites. About 82% of these persons live near five of the millsites. No persons were found living within 5 kilometers of six of the millsites. Tailings area measurements include the surface area of tailings in impoundments, heap-leached ore, and carryover tailings in evaporation ponds. Approximately 4,000 acres of tailings surfaces were measured for the 21 millsites. About 55% of the tailings surfaces were dry, 11% wet, and the remainder ponded. The average tailings surface area for the millsites is about 200 acres and ranges from 7 to 813 acres

  20. 36 CFR 262.11 - Impounding of dogs.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 2 2010-07-01 2010-07-01 false Impounding of dogs. 262.11... ENFORCEMENT SUPPORT ACTIVITIES Impoundments and Removals § 262.11 Impounding of dogs. Any dog found running at large in a part of the National Forest System, which has been closed to dogs running at large, may be...

  1. 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

  2. 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.

  3. Oilsand tailings : solving the issues

    Energy Technology Data Exchange (ETDEWEB)

    Granson, E.

    2008-11-15

    Oilsands tailings management is an integral part of oil sands research and development. Studies to decrease land disturbance and to resolve environmental and safety issues are underway at several government agencies and industry groups, including the Alberta Energy Research Institute, the Oil Sands Tailings Research Facility and Natural Resources Canada's CANMET Advanced Separation Technologies division. Fresh tailings that come from the bitumen extraction process are composed of 85 to 90 per cent water and 10 to 15 per cent solids having the consistency of muddy water. The 3 zones that develop following discharge into the tailings ponds are 3 metres of clear water; residual hydrocarbons that float on the surface; and, a 1 metre zone of water and settling clay particles known as mature fine tailings (MFT) which comprise about 90 per cent of the volume of the tailings pond. The tailings ponds must be built in areas where there is no bitumen suitable for surface mining. The impounded area is surrounded by tailings dykes built from local overburden materials. As such, tailings ponds are managed as dams according to Alberta Dam Safety regulation requirements. Dam stability is increased by the installation of internal seepage control measures. This article described the key guidelines and objectives for the construction of tailings ponds. It also described the 3 primary types of reclamation settings, namely aquatic reclamation, wetland reclamation and terrestrial reclamation. Water removed from the MFT can be recycled back to the plant to reduce the amount of water used from the river. Although this contributes to lower energy costs, there are challenges regarding salt levels that builds up in piping and equipment. The presence of water in the tailings also prevents tailings reclamation. In addition to mechanical systems to remove water, researchers are also considering the use of chemicals and natural processes. In the consolidated tailings (CT) process, the

  4. Closure certification report: TA-35 TSL-125 surface impoundment

    International Nuclear Information System (INIS)

    1991-01-01

    This report summarizes the actions that were taken to clean close the TA-35 TSL-125 surface impoundment Building 125 is used for developing electron guns and related laser assemblies/equipment for a Laser Technology Research Program at the Laboratory. There is no permanent outfall from the surface impoundment; however, the impoundment accidentally overtopped on December 3, 1986, spilling an unknown volume of insulating oil and water into Ten Site Canyon. Sandbags were installed around the surface impoundment on June 25, 1988, to provide additional freeboard in the impoundment and reduce the risk of overtopping during a precipitation event. On July 1, 1988, the impoundment again overtopped releasing an unknown volume of insulating oil and water. Actions taken include removal of waste from the surface impoundment and its associated structures, decontamination of the floor trough and piping inside Building 125, grouting of the piping connecting the floor drain/trough system to the impoundment, decontamination, removal, and disposal of the impoundment liner and sandbags lining the top of the impoundment, and removal and disposal of contaminated soil underlying the impoundment area. Procedures followed to verify that clean closure objectives have been met are also documented in this report. Initial verification was performed through an extensive soil sampling and analysis program

  5. 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

  6. Current practices for the management and confinement of uranium mill tailings

    International Nuclear Information System (INIS)

    1992-01-01

    This report discusses the current practices used in the design siting, construction and closeout of impoundment facilities for uranium mill tailings. The objective is to present an integrated overview of the technological, safety and radiation protection aspects of these topics in order to ensure that the potential radiological and non-radiological risks associated with the management of uranium mill tailings are minimized now and in the future. The report: identifies the nature and source of radioactive and non-radioactive pollutants in uranium mill tailings; identifies the important mechanisms by which pollutants can be released from the tailings impoundment; reviews radiation protection aspects of these mechanisms; describes the pathways by which the pollutants may reach humans; describes some of the site selection and design options and considerations for final stabilization and rehabilitation of tailings impoundments; describes the methods of assessing closure strategies; describes long term responsibilities for tailings management and financial assurance to ensure these responsibilities; and reviews the magnitude and probability of occurrence of the hazards arising, with the aim of ensuring that the risks presented are acceptable. Because of the complexity of the pollutant release mechanisms and the site specific nature of the design and management controls that can be used, it is not possible for a report of this nature to be either exhaustive or detailed in all respects. The methods of confinement employed for any particular tailings impoundment will depend on the country, its climate, demography and its site specific performance criteria which should be defined by the relevant competent authorities. Both operating and post-operating conditions are considered. After shutdown of the mill and stabilization of the tailings, continuing surveillance and maintenance should be considered until the integrity and durability of the tailings impoundment have been

  7. 32 CFR 634.53 - Disposition of vehicles after impoundment.

    Science.gov (United States)

    2010-07-01

    ... 32 National Defense 4 2010-07-01 2010-07-01 true Disposition of vehicles after impoundment. 634.53 Section 634.53 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY (CONTINUED) LAW ENFORCEMENT AND CRIMINAL INVESTIGATIONS MOTOR VEHICLE TRAFFIC SUPERVISION Impounding Privately Owned Vehicles...

  8. 32 CFR 634.51 - Procedures for impoundment.

    Science.gov (United States)

    2010-07-01

    ... 32 National Defense 4 2010-07-01 2010-07-01 true Procedures for impoundment. 634.51 Section 634.51 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY (CONTINUED) LAW ENFORCEMENT AND CRIMINAL INVESTIGATIONS MOTOR VEHICLE TRAFFIC SUPERVISION Impounding Privately Owned Vehicles § 634.51...

  9. 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.)

  10. Sediment quality in freshwater impoundments at Savannah National Wildlife Refuge

    Science.gov (United States)

    Winger, P.V.; Lasier, P.J.

    2004-01-01

    Freshwater impoundments at Savannah National Wildlife Refuge (NWR), South Carolina, provide an important habitat for wildlife species, but degraded sediment quality in the Savannah River downstream of the discharge from two impoundments have caused concern about potential contaminant problems within the impoundments. The quality of sediments from five impoundments (impoundments no. 1, 2, 6, 7, and 17) on the NWR was evaluated using physical and chemical characterization, contaminant concentrations (metals, organochlorine pesticides, polychlorinated biphenyls, and polycyclic aromatic hydrocarbons), and toxicity testing. Survival of Hyalella azteca (freshwater amphipod) exposed for 28 days to solid-phase sediments was not significantly different from controls, but growth was significantly decreased at several sites. Survival in 96-hour exposures to sediment pore water was significantly decreased at most sites. Factors contributing to the toxic responses were low pH (3.7 to 4.1), ammonia (20 mg/L), and increased concentrations of cations in the pore water. The excess of simultaneously extracted metals over the acid volatile sulfides in the sediments was also typical of sites displaying decreased sediment quality. Elemental concentrations in pore water were negatively correlated with pH, and the highest concentrations were observed in impoundment no. 7. The acidic nature of the sediment in this impoundment was exacerbated by recent draining, burning, and disking, which allowed oxidation of the previously anoxic wetland sediment. Sediment disturbance and mixing of vegetation into the sediments by disking may also have contributed to the formation of ammonia caused by microbial decomposition of the fragmented organic matter. Contaminants were not detected in sediments from the impoundments, but releases of acidic water with increased levels of sediment cations from the impoundments may have contributed to the degraded sediment conditions previously observed in the river

  11. 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

  12. Hypersalinity reduces the risk of cyanide toxicosis to insectivorous bats interacting with wastewater impoundments at gold mines.

    Science.gov (United States)

    Griffiths, Stephen R; Donato, David B; Lumsden, Linda F; Coulson, Graeme

    2014-01-01

    Wildlife and livestock that ingest bioavailable cyanide compounds in gold mining tailings dams are known to experience cyanide toxicosis. Elevated levels of salinity in open impoundments have been shown to prevent wildlife cyanide toxicosis by reducing drinking and foraging. This finding appears to be consistent for diurnal wildlife interacting with open impoundments, however the risks to nocturnal wildlife of cyanide exposure are unknown. We investigated the activity of insectivorous bats in the airspace above both fresh (potable to wildlife) and saline water bodies at two gold mines in the goldfields of Western Australian. During this study, cyanide-bearing solutions stored in open impoundments at both mine sites were hypersaline (range=57,000-295,000 mg/L total dissolved solids (TDS)), well above known physiological tolerance of any terrestrial vertebrate. Bats used the airspace above each water body monitored, but were more active at fresh than saline water bodies. In addition, considerably more terminal echolocation buzz calls were recorded in the airspace above fresh than saline water bodies at both mine sites. However, it was not possible to determine whether these buzz calls corresponded to foraging or drinking bouts. No drinking bouts were observed in 33 h of thermal video footage recorded at one hypersaline tailings dam, suggesting that this water is not used for drinking. There is no information on salinity tolerances of bats, but it could be assumed that bats would not tolerate salinity in drinking water at concentrations greater than those documented as toxic for saline-adapted terrestrial wildlife. Therefore, when managing wastewater impoundments at gold mines to avoid wildlife mortalities, adopting a precautionary principle, bats are unlikely to drink solutions at salinity levels ≥50,000 mg/L TDS. © 2013 Published by Elsevier Inc.

  13. Field performance assessment of synthetic liners for uranium tailings ponds: a status report

    International Nuclear Information System (INIS)

    Mitchell, D.H.; Spanner, G.E.

    1984-03-01

    The objective of this study is to provide a database to support US Nuclear Regulatory Commission (NRC) licensing of uranium tailings leachate isolation impoundments. This objective is being accomplished by determining the effectiveness of design, installation, and quality assurance practices associated with uranium mill tailings impoundments with flexible membrane liners. The program includes testing of chemical resistance and physical performance of liners, leak detection systems, and seam inspection techniques. This report presents the status of the program through September 1983. The report addresses impoundment design, installation, and inspection techniques used by the uranium milling industry. To determine the relative successes of these techniques, information has been collected from consultants, mill operators, and the synthetic liner industry. Progress in experimental tasks on chemical resistance of liners, physical properties of liners, and nondestructive examination of seams is reported. 25 references, 9 figures, 13 tables

  14. 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

  15. Contingency planning and risk analysis for water and tailings management at Ranger Uranium Mines

    International Nuclear Information System (INIS)

    McNally, P.E.

    1986-01-01

    This paper describes some of the more likely risks and contingency procedures associated with the extremely variable monsoonal climate of the Alligator Rivers region in the Northern Territory in relation to the Ranger Uranium Mine. The tailings management system is basically a large storage impoundment and a reticulation system that delivers tailings sludge and recycles supernatant water. It is a closed circuit within the water management system and is dealt with as an integral part of that system

  16. Interior drains for open pit disposal of uranium mill tailings

    International Nuclear Information System (INIS)

    Staub, W.P.

    1978-01-01

    A conceptualized interior drainage system is presented for reducing the environmental impact on natural groundwater by disposal of uranium mill tailings in the mined-out open pit. The evaporation/seepage ratio can be increased through the use of interior drains, long-term monitoring of groundwater quality can be eliminated, and the open pit will not require an extensive liner. Other advantages not related to groundwater are: control of fugitive dust and radon emanation during mill operations and timely reclamation after the impoundment is filled with tailings

  17. 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.

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

    Directory of Open Access Journals (Sweden)

    Michael Stovern

    2016-01-01

    Full Text Available 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. 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

  20. French Modular Impoundment: Final Cost and Performance Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Drown, Peter [French Development Enterprises, LLC, North Billerica, MA (United States); French, Bill [French Development Enterprises, LLC, North Billerica, MA (United States)

    2017-05-17

    This report comprises the Final Cost and Performance Report for the Department of Energy Award # EE0007244, the French Modular Impoundment (aka the “French Dam”.) The French Dam is a system of applying precast modular construction to water control structures. The “French Dam” is a term used to cover the construction means/methods used to construct or rehabilitate dams, diversion structures, powerhouses, and other hydraulic structures which impound water and are covered under FDE’s existing IP (Patents # US8414223B2; US9103084B2.)

  1. Effect of weir impoundments on methane dynamics in a river

    Czech Academy of Sciences Publication Activity Database

    Bednařík, A.; Blaser, M.; Matoušů, Anna; Hekera, P.; Rulík, M.

    2017-01-01

    Roč. 584, April (2017), s. 164-174 ISSN 0048-9697 R&D Projects: GA ČR(CZ) GA13-00243S Institutional support: RVO:60077344 Keywords : methane production * methane emission * methane ebullition * river impoundment * river sediment Subject RIV: DA - Hydrology ; Limnology OBOR OECD: Marine biology, freshwater biology, limnology Impact factor: 4.900, year: 2016

  2. 32 CFR 634.23 - Specified consent to impoundment.

    Science.gov (United States)

    2010-07-01

    ... 32 National Defense 4 2010-07-01 2010-07-01 true Specified consent to impoundment. 634.23 Section 634.23 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY (CONTINUED) LAW ENFORCEMENT AND CRIMINAL INVESTIGATIONS MOTOR VEHICLE TRAFFIC SUPERVISION Motor Vehicle Registration § 634.23...

  3. Propagation of a cadmium spill through an impounded river system

    NARCIS (Netherlands)

    Klaver, G.T.; Joziasse, J.; Bakker, I.

    2009-01-01

    In this paper, the influence of impoundments (sluices, weirs, etc.) and stream components (tributaries, river branches, associated canals) on the metal content in water and suspended particulate matter (SPM) in the Dutch part of the River Meuse is assessed using the decrease in the cadmium content

  4. Overland erosion of uranium-mill-tailings impoundments: physical processes and computational methods

    International Nuclear Information System (INIS)

    Walters, M.H.

    1983-03-01

    The surface runoff and erosional processes of watersheds caused by rainfall-runoff are reviewed. Soil properties, topography, and rainstorm distribution are discussed with respect to their effects on soil erosion. The effects of climate and vegetation are briefly presented. Regression models and physical process simulation models are reviewed

  5. The Wireless Sensor Network (WSN) Based Coal Ash Impoundments Safety Monitoring System

    Science.gov (United States)

    Sun, E. J.; Nieto, A.; Zhang, X. K.

    2017-01-01

    Coal ash impoundments are inevitable production of the coal-fired power plants. All coal ash impoundments in North Carolina USA that tested for groundwater contamination are leaking toxic heavy metals and other pollutants. Coal ash impoundments are toxic sources of dangerous pollutants that pose a danger to human and environmental health if the toxins spread to adjacent surface waters and drinking water wells. Coal ash impoundments failures accidents resulted in serious water contamination along with toxic heavy metals. To improve the design and stability of coal ash impoundments, the Development of a Coal Ash Impoundment Safety Monitoring System (CAISM) was proposed based on the implementation of a wireless sensor network (WSN) with the ability to monitor the stability of coal ash impoundments, water level, and saturation levels on-demand and remotely. The monitoring system based on a robust Ad-hoc network could be adapted to different safety conditions.

  6. 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

  7. Closure certification report: TA-35 TSL-125 surface impoundment

    International Nuclear Information System (INIS)

    1991-01-01

    This closure report documents closure activities for the TA-35 TSL-125 surface impoundment and associated structures at Los Alamos National Laboratory (the Laboratory). Prior to formal approval of the closure plan, the decision was made to proceed with closure activities to prevent any further releases from the site following informal discussions with New Mexico Environment Department (NMED) personnel. The closure plan is a revision of the previously submitted draft dated July 1988. Clean closure of the TSL-125 site was accomplished through: Removal and proper disposal of all wastes contained within the surface impoundment system; Decontamination and/or removal and proper disposal of the surface impoundment, its associated structures, and contaminated soil underlying the impoundment area; Sampling and analysis of soil to determine the presence and concentrations of any hazardous constituents remaining in the soil at the TSL-125 site; and Demonstration through a risk assessment that any constituents remaining in the soil at the TSL-125 site pose no threat to human health and the environment. All remaining soil concentrations of hazardous constituents were below health-based action levels. Analytical results indicated that benzidine, n-nitrosodimethylamine, and n-nitrosodi-n-propylamine were not detected at or above their limits of quantitation and beryllium was not present at or above its laboratory detection limit. However, the limits of quantitation and detection for these constituents were greater than their calculated health-based action levels. To demonstrate that these constituents were not present, historical data was researched and it was determined that the constituents were not utilized at the Building 125 site. 4 refs., 8 figs., 1 tab

  8. Stochastic Modelling of the Hydraulic Anisotropy of Ash Impoundment Sediment

    Science.gov (United States)

    Slávik, Ivan

    2017-12-01

    In the case reported here the impoundments of a 400 MW coal heated power plant with an annual production of about 1.5 million tons of fuel ash are of the cross-valley type, operated by the simple and cheap „upstream method”. The aim of the research was to determine overall and local values of the permeability in horizontal as well as in vertical direction and the anisotropy of the thin-layered sedimented ash. The coal ashes are hydraulically transported through pipelines in form of a slurry and periodically floated on the beach of the impoundment. The ashes are deposited in the form of a thin-layered sediment, with random alternation of layers with a coarser or finer granularity. The ash impoundment sediment is anthropogenic sediment with horizontally laminated texture. Therefore, the sediment is anisotropic from the viewpoint of water seepage. The knowledge of the permeability and the seepage anisotropy of the sediment is a basic requirement for the design of an appropriate dewatering system. The seepage anisotropy of the ash sediment has been checked by means of stochastic modelling, based on the correlation between the effective grain diameter and the coefficient of permeability of the ash: the effective grain diameter and the thickness of individual layers have been proposed to be random events.

  9. The tailings technology suite

    Energy Technology Data Exchange (ETDEWEB)

    Jaremko, Deborah

    2011-10-15

    Oilsands tailing ponds contain leftover bitumen and asphaltenes, which are dangerous to local wildlife. The Oil Sands Tailings Consortium (OSTCS) was founded by all major mining players and aims to prompt collaboration within the oilsands industry to reclaim the tailings area. Each company has hitherto worked on different tailings management technologies, often duplicating efforts. Some technologies proposed by these oilsands miners were introduced in this article.

  10. Metal-residence sites in mine tailings in the Magdalena District, New Mexico, USA

    Energy Technology Data Exchange (ETDEWEB)

    Larocque, A.C.L. [Univ. of Manitoba, Winnipeg, Manitoba (Canada). Dept. of Geological Sciences; Chapin, C.E. [New Mexico Bureau of Mines and Mineral Resources, Socorro, NM (United States); Laughlin, A.W. [ICF Kaiser Ltd., Los Alamos, NM (United States); Hickmott, D. [Los Alamos National Lab., NM (United States)

    1996-05-01

    Mineralization in the Kelly Mining Camp is hosted by the Mississippian Kelly Limestone and comprises Zn-Pb skarn, replacement, and vein deposits related to Tertiary intrusive activity. The ore consists of primary (hypogene) sulfide mineralization which has been oxidized near surface to form secondary (supergene) mineralization. A zone of secondary sulfide-enrichment separates the sulfide and oxide ores. Mine tailings in the camp contain primary sulfide, oxide and gangue minerals, secondary (supergene) minerals formed during weathering of the primary ore, and tertiary minerals formed by alteration of hypogene and supergene assemblages after deposition in the tailings impoundment.

  11. 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...

  12. Green mines, green energy : generating green energy on tailings

    Energy Technology Data Exchange (ETDEWEB)

    Tisch, B. [Natural Resources Canada, Ottawa, ON (Canada). CANMET Mining and Mineral Sciences Laboratories

    2008-04-01

    This article described a pilot program conducted to remediate tailings impoundment areas with organic wastes in order to yield agricultural lands for energy crops and biofuels production. The project was developed by Natural Resources Canada as a consortium of industry and research stakeholders. Further initiatives may include the establishment of wetlands areas to act as passive treatment systems. The rehabilitation of mine tailings offers significant opportunities for the long term management of paper mill biosolids and composted municipal wastes. It is not yet known what the impact of the thick cover layers of organic material will be on the chemistry, hydrology, and stability of the tailings. A column leaching study conducted to assess the net effect of biosolids on tailings has demonstrated an extensive blackening of the biosolids and tailings interface after the application of paper mill biosolids. The black precipitates were identified as iron sulphide. The columns will remain operational for a 3-year period in order to observe longer term interactions. Batch neutralization tests used to stimulate conventional lime and air treatment system for raw water treatments have demonstrated that organic carbon has no significant impact on effluent treatability. It was concluded that growth studies have shown that above ground growth or corn and canola was good, although root growth was poorer than expected. 3 refs., 8 figs.

  13. 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.

  14. Talking tails : quantifying the development of tail biting in pigs

    NARCIS (Netherlands)

    Zonderland, J.J.

    2010-01-01

    Tail biting is an adverse behaviour characterised by manipulation of a pig’s tail by another pig resulting in tail damage and a possible tail biting outbreak. Tail biting is a common problem in the pig husbandry causing economic losses and reduced animal welfare worldwide. To prevent tail biting,

  15. Characterization plan for the waste holding basin (3513 impoundment)

    International Nuclear Information System (INIS)

    Stansfield, R.G.; Francis, C.W.

    1986-09-01

    US Department of Energy (DOE) facilities are required to comply fully with all federal and state regulations. In response to this requirement, the Oak Ridge National Laboratory (ORNL) has established the remedial action program, to provide comprehensive management of areas where past research, development, and waste management activities have been conducted and have resulted in residual contamination of facilities or the environment. One of the objectives of this program is to define the extent of contamination at these sites. The intent is to document the known environmental characteristics of the sites and identify the additional actions, such as sampling, analytical measurements, and modeling, necessary to confirm contamination and the possible migration of contaminants from the sites. One of these sites is the waste holding basin (3513 impoundment). The 3513 impoundment is an unlined waste settling basin constructed in 1944 for collection of ORNL wastewater before its discharge into White Oak Creek. Operation of the facility ceased in 1976 when a new process waste treatment plant came into operation. Considerable site-specific environmental information has been developed over the years relative to the type and quantities of radionuclides and hazardous substances contained in the pond water and sediment. The concentrations and patterns of distribution for many of the radionuclides in the aquatic biota as well as for the terrestrial plants growing on the berm of the impoundment have been determined by DOE ecological studies. Recently, some data were collected that evaluate the extent of contaminant movement to the groundwater. Results from these studies are summarized in this report. Also included in this report is an outline of additional tasks needed to obtain the necessary information to model the transport and dose pathways of hazardous substances from the site

  16. Characterization plan for the waste holding basin (3513 impoundment)

    Energy Technology Data Exchange (ETDEWEB)

    Stansfield, R.G.; Francis, C.W.

    1986-09-01

    US Department of Energy (DOE) facilities are required to comply fully with all federal and state regulations. In response to this requirement, the Oak Ridge National Laboratory (ORNL) has established the remedial action program, to provide comprehensive management of areas where past research, development, and waste management activities have been conducted and have resulted in residual contamination of facilities or the environment. One of the objectives of this program is to define the extent of contamination at these sites. The intent is to document the known environmental characteristics of the sites and identify the additional actions, such as sampling, analytical measurements, and modeling, necessary to confirm contamination and the possible migration of contaminants from the sites. One of these sites is the waste holding basin (3513 impoundment). The 3513 impoundment is an unlined waste settling basin constructed in 1944 for collection of ORNL wastewater before its discharge into White Oak Creek. Operation of the facility ceased in 1976 when a new process waste treatment plant came into operation. Considerable site-specific environmental information has been developed over the years relative to the type and quantities of radionuclides and hazardous substances contained in the pond water and sediment. The concentrations and patterns of distribution for many of the radionuclides in the aquatic biota as well as for the terrestrial plants growing on the berm of the impoundment have been determined by DOE ecological studies. Recently, some data were collected that evaluate the extent of contaminant movement to the groundwater. Results from these studies are summarized in this report. Also included in this report is an outline of additional tasks needed to obtain the necessary information to model the transport and dose pathways of hazardous substances from the site.

  17. Run-of-River Impoundments Can Remain Unfilled While Transporting Gravel Bedload: Numerical Modeling Results

    Science.gov (United States)

    Pearson, A.; Pizzuto, J. E.

    2015-12-01

    Previous work at run-of-river (ROR) dams in northern Delaware has shown that bedload supplied to ROR impoundments can be transported over the dam when impoundments remain unfilled. Transport is facilitated by high levels of sand in the impoundment that lowers the critical shear stresses for particle entrainment, and an inversely sloping sediment ramp connecting the impoundment bed (where the water depth is typically equal to the dam height) with the top of the dam (Pearson and Pizzuto, in press). We demonstrate with one-dimensional bed material transport modeling that bed material can move through impoundments and that equilibrium transport (i.e., a balance between supply to and export from the impoundment, with a constant bed elevation) is possible even when the bed elevation is below the top of the dam. Based on our field work and previous HEC-RAS modeling, we assess bed material transport capacity at the base of the sediment ramp (and ignore detailed processes carrying sediment up and ramp and over the dam). The hydraulics at the base of the ramp are computed using a weir equation, providing estimates of water depth, velocity, and friction, based on the discharge and sediment grain size distribution of the impoundment. Bedload transport rates are computed using the Wilcock-Crowe equation, and changes in the impoundment's bed elevation are determined by sediment continuity. Our results indicate that impoundments pass the gravel supplied from upstream with deep pools when gravel supply rate is low, gravel grain sizes are relatively small, sand supply is high, and discharge is high. Conversely, impoundments will tend to fill their pools when gravel supply rate is high, gravel grain sizes are relatively large, sand supply is low, and discharge is low. The rate of bedload supplied to an impoundment is the primary control on how fast equilibrium transport is reached, with discharge having almost no influence on the timing of equilibrium.

  18. Groundwater monitoring at three Oak Ridge National Laboratory inactive waste impoundments: results after one year

    Energy Technology Data Exchange (ETDEWEB)

    Francis, C. W.; Stansfield, R. G.

    1986-10-01

    To determine if the migration of potential contaminants from three inactive waste impoundments at Oak Ridge National Laboratory poses a threat to groundwater quality, at least one upgradient groundwater monitoring well and threee downgradient monitoring wells were installed at each impoundment in early 1985. These three unlined impoundments, formerly used to collect and, in some instances, treat wastewater are: the 3513 impoundment; the Old Hydrofracture Facility (OHF) impoundment; and the Homogeneous Reactor Experimnt No. 2 impoundment. Groundwater samples were collected quarterly for one year. Analyses were conducted for the groundwater protection parameters promulgated by the Resource Conservation and Recovery Act. The groundwater samples were also analyzed for polychlorinated biphenyls, copper, nickel, zinc, /sup 90/Sr, /sup 137/Cs, and tritium. The contaminants found most often to affect groundwater quality at all three waste impoundments were radionuclides. For example, mean concentrations of gross beta and gross alpha activity exceeded drinking water limits at all three sites. The gross beta limit was exceeded at the 3513 and OHF impoundments by either /sup 90/Sr or tritium levels. At the 3513 impoundment, there was substantial evidence that the downgradient groundwater has been contaminated by chromium and lead and possibly by halogenated organic compounds. At the OHF impoundment, the mean level of tritium measured in the upgradient well (about 91,000 Bq/L as compared with 80,000 Bq/L in the downgradient wells) indicated that the groundwater quality has been affected by the radioactive wastes buried in the low-level radioactive waste burial ground solid waste storage area-5 upgradient of the impoundment. Testing for groundwater contamination, disclosed statistically significant contamination at all three sites.

  19. Groundwater monitoring at three Oak Ridge National Laboratory inactive waste impoundments: results after one year

    International Nuclear Information System (INIS)

    Francis, C.W.; Stansfield, R.G.

    1986-10-01

    To determine if the migration of potential contaminants from three inactive waste impoundments at Oak Ridge National Laboratory poses a threat to groundwater quality, at least one upgradient groundwater monitoring well and threee downgradient monitoring wells were installed at each impoundment in early 1985. These three unlined impoundments, formerly used to collect and, in some instances, treat wastewater are: the 3513 impoundment; the Old Hydrofracture Facility (OHF) impoundment; and the Homogeneous Reactor Experimnt No. 2 impoundment. Groundwater samples were collected quarterly for one year. Analyses were conducted for the groundwater protection parameters promulgated by the Resource Conservation and Recovery Act. The groundwater samples were also analyzed for polychlorinated biphenyls, copper, nickel, zinc, 90 Sr, 137 Cs, and tritium. The contaminants found most often to affect groundwater quality at all three waste impoundments were radionuclides. For example, mean concentrations of gross beta and gross alpha activity exceeded drinking water limits at all three sites. The gross beta limit was exceeded at the 3513 and OHF impoundments by either 90 Sr or tritium levels. At the 3513 impoundment, there was substantial evidence that the downgradient groundwater has been contaminated by chromium and lead and possibly by halogenated organic compounds. At the OHF impoundment, the mean level of tritium measured in the upgradient well (about 91,000 Bq/L as compared with 80,000 Bq/L in the downgradient wells) indicated that the groundwater quality has been affected by the radioactive wastes buried in the low-level radioactive waste burial ground solid waste storage area-5 upgradient of the impoundment. Testing for groundwater contamination, disclosed statistically significant contamination at all three sites

  20. Speciation of radium in uranium mill tailings from Ecarpiere (Vendee, France)

    International Nuclear Information System (INIS)

    Somot, S.; Pagel, M.

    1997-01-01

    The uranium ores of Vendee (France) have been treated with sulfuric acid and mill tailings disposed of in an impoundment at Ecarpiere. Sequential and selective extractions have been performed to determine the amount of 226 RA, and also metals and uranium, bound to different mineralogical phases. The 226 Ra fraction bound to gypsum is only 10-20% of the 226 Ra concentration in the tailings, the 226 Ra fraction bound to Fe and Mn minerals and barite (5-10 weight % of the tailings) ranges from 75 to 85% and the residual silicates and accessory minerals (60 to 72 weight % of the tailings) contain only 3 to 7% of the 226 Ra concentration. (author)

  1. Evaluation of neutralization treatment processes and their use for uranium tailings solutions

    International Nuclear Information System (INIS)

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

    1985-01-01

    The potential for groundwater contamination from the typically acidic mill wastes that are disposed of in tailings impoundments is of primary concern at uranium mill sites in the US. Solution-treatment processes provide a system for limiting the environmental impact from acidic seepage. Treatment of uranium tailings solutions from evaporation ponds, underdrains, and surface seeps could aid in decommissioning active sites or be used as an emergency measure to avert possible uncontrolled discharges. At present, neutralization processes appear to be best suited for treating uranium mill tailings solution because they can, at a reasonable cost, limit the solution concentration of many contaminants and thus reduce the potential for groundwater contamination. However, the effectiveness of the neutralization process depends on the reagent used as well as the chemistry of the waste stream. This article provides a description of neutralization processes, an assessment of their performance on acidic uranium tailings leachates, and recommendations for their use at US uranium mill sites

  2. 40 CFR 63.134 - Process wastewater provisions-surface impoundments.

    Science.gov (United States)

    2010-07-01

    ... wastewater provisions—surface impoundments. (a) For each surface impoundment that receives, manages, or...-supported structure or rigid cover) and a closed-vent system that routes the organic hazardous air... to float on the liquid surface during normal operations, and to form a continuous barrier over the...

  3. 32 CFR 634.52 - Search incident to impoundment based on criminal activity.

    Science.gov (United States)

    2010-07-01

    ... 32 National Defense 4 2010-07-01 2010-07-01 true Search incident to impoundment based on criminal activity. 634.52 Section 634.52 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY (CONTINUED) LAW ENFORCEMENT AND CRIMINAL INVESTIGATIONS MOTOR VEHICLE TRAFFIC SUPERVISION Impounding...

  4. 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

  5. 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.

  6. 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

  7. Eutrophication levels of some South African impoundments. IV. Vaal Dam

    CSIR Research Space (South Africa)

    Steyn, DJ

    1976-04-01

    Full Text Available I?d/st. Loners I, 74, I ?34-I 42. TOERIEN, D. F., STEtN, D.J. and KOHLMEYER, 5.1. (1975a).The nitrogen yield coellieien t of the g ?ccii alga .Seleooastrsmn rapr,corn,tesm Printz. S. Afe. J. Sri., 7!, 217-218. TOERtEN, D.F.,HVMAN,KATHYL.5nd... inere;iae(l the \\G P In? between 7,1- and I 1,2 mg/r? lbr t?verv nile pet? t?t?ttt v/v) added_Nitrogen and phosphorus wert? the important algal growth?limiting ntltrients in the impoundment. Plant nntt-ients adsorbed onto clay particles could ht...

  8. 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.

  9. 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

  10. 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

  11. 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 10,000 Hz. 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.

  12. 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

  13. Evaluation of chemical stabilizers and windscreens for wind erosion control of uranium mill tailings

    Energy Technology Data Exchange (ETDEWEB)

    Elmore, M.R.; Hartley, J.N.

    1984-08-01

    Potential wind erosion of uranium mill tailings is a concern for the surface disposal of tailings at uranium mills. Wind-blown tailings may subsequently be redeposited on areas outside the impoundment. Pacific Northwest Laboratory (PNL) is investigating techniques for fugitive dust control at uranium mill tailings piles. Laboratory tests, including wind tunnel studies, were conducted to evaluate the relative effectiveness of 43 chemical stabilizers. Seventeen of the more promising stabilizers were applied to test plots on a uranium tailings pile at the American Nuclear Corporation-Gas Hills Project mill site in central Wyoming. The durabilities of these materials under actual site conditions were evaluated over time. In addition, field testing of commercially available windscreens was conducted. Test panels were constructed of eight different materials at the Wyoming test site to compare their durability. A second test site was established near PNL to evaluate the effectiveness of windscreens at reducing wind velocity, and thereby reduce the potential for wind erosion of mill tailings. Results of the laboratory land field tests of the chemical stabilizers and windscreens are presented, along with costs versus effectiveness of these techniques for control of wind erosion at mill tailings piles. 12 references, 4 figures, 6 tables.

  14. 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.

  15. 40 CFR 63.943 - Standards-Surface impoundment vented to control device.

    Science.gov (United States)

    2010-07-01

    ... applicable, to the surface impoundment. (ii) To remove accumulated sludge or other residues from the bottom... the following requirements: (1) The cover and its closure devices shall be designed to form a...

  16. Efficiency of baited hoop nets for sampling catfish in southeastern U.S. small impoundments

    Science.gov (United States)

    Wallace, Benjamin C.; Weaver, Daniel M.; Kwak, Thomas J.

    2011-01-01

    Many U.S. natural resource agencies stock catfish (Ictaluridae) into small impoundments to provide recreational fishing opportunities. However, effective standardized methods for sampling catfish in small impoundments have not been developed for wide application, particularly in the southeastern United States. We evaluated the efficiency of three bait treatments (i.e., soybean cake, sunflower cake, and no bait) of tandem hoop nets in two North Carolina small impoundments during the fall of 2008 and spring of 2009 in a factorial experimental design. The impoundments were stocked with catchable-size channel catfish Ictalurus punctatus at contrastingly low (5.5 fi sh/ha) and high (90.0 fi sh/ha) rates prior to our sampling. Nets baited with soybean cake consistently sampled more channel catfish than any other treatment. Channel catfish catch ranged as high as 3,251 fi sh per net series during the fall in nets baited with soybean cake in the intensively stocked impoundment and was up to 8.5 and 15.3 times higher during the fall than in the spring in each impoundment. Nets baited with soybean cake sampled significantly (12 and 24 times) more channel catfish than those with no bait in the two impoundments. These trends did not occur among other catfish species. Nonictalurid fish and turtle catch was higher during spring compared to that of fall, corresponding with low channel catfish catches. Our results indicate that tandem hoop nets baited with soybean cake during the fall is a more efficient method for sampling channel catfish compared to nets baited with sunflower cake or no bait in spring or fall. Our findings validate this technique for application in southeastern U.S. small impoundments to assess catfish abundance to guide management and evaluate the success of catfish stocking programs.

  17. 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.

  18. Handbook for the design, selection, and construction of a rock cover for retired uranium-mill tailings

    International Nuclear Information System (INIS)

    Parker, G.B.

    1982-09-01

    As part of a Nuclear Regulatory Commission (NRC) study to assess the long-term protection of retired uranium mill tailings, the Pacific Northwest Laboratory (PNL) is developing a Handbook to guide the design, selection, and construction of a rock cover (riprap) for decommissioned and reclaimed uranium-mill tailings. The rock cover is designed for long-term protection of mill tailings from wind and water erosion. The purpose of the Handbook is twofold. First, it can be used as a manual by the uranium mill operators for designing, selecting, and constructing a rock cover. Second, the Handbook can be used as a guide to help the NRC evaluate the decommissioning and reclamation plans submitted to them by mill operators. Although the Handbook is not site-specific, it is structured to allow the design of a rock cover for any NRC-licensed tailings impoundment

  19. Tailings From Mining Activities, Impact on Groundwater, and Remediation

    Directory of Open Access Journals (Sweden)

    Khalid Al-Rawahy

    2001-12-01

    Full Text Available Effluent wastes from mining operations and beneficiation processes are comprized mostly of the following pollutants: total suspended solids (TTS, alkalinity or acidity (pH, settleable solids, iron in ferrous mining, and dissolved metals in nonferrous mining. Suspended solids consist of small particles of solid pollutants that resist separation by conventional means. A number of dissolved metals are considered toxic pollutants. The major metal pollutants present in ore mining and beneficiation waste waters include arsenic, cadmium, copper, lead, mercury, nickel, and zinc. Tailings ponds are used for both the disposal of solid waste and the treatment of waste-water streams. The supernatant decanted from these ponds contains suspended solids and, at times, process reagents introduced to the water during ore beneficiation. Leakage of material from tailings pond into groundwater is one possible source of water pollution in the mining industry. Percolation of waste-water from impoundment may occur if tailings ponds are not properly designed. This paper addresses potential groundwater pollution due to effluent from mining activities, and the possible remediation options.

  20. Pournari Dam (W. Greece) Impoundment and Triggered Seismicity

    Science.gov (United States)

    Pavlou, K.; Kouskouna, V.; Makropoulos, K.; Drakatos, G.; Petrou, P.

    2012-04-01

    The Pournari dam is located in the seismically active area of W. Greece, close to Arta. The height of the dam is 87m, with maximum water level height at 126m and maximum volume 865X106m3. The first impoundment commenced in January 1981, and was accompanied by a considerable number of low magnitude seismic events, as well as two major ones on March 10 and April 10, 1981, with magnitudes ML=5.6 and ML=4.7 and focal depths 13km and 10km, respectively, all located in the broader area of the dam. Potential triggering of the second event was studied through the calculation of Coulomb stress changes distribution, due to the occurrence of the first ML=5.6 event. Additionally, the detailed study of temporal correlation between water level increase and seismicity showed triggering seismicity due to both the initial filling and the disordered structure, controlled by the presence of evaporites, south and west of Pournari dam area. Further processing of the recorded seismicity for the period 1982-2010, in comparison with the variations of Pournari dam water level, presented an increase of shallow seismicity in the vicinity of the reservoir up to a 10 km distance -in contrast to the initial period, characterized by a number of deeper events- which was due to the background response change from undrained to drained status.

  1. Presentations from the 1992 Coal Mining Impoundment Informational Meeting

    Energy Technology Data Exchange (ETDEWEB)

    1993-12-31

    On May 20 and 21, 1992, the MSHA Coal Mining Impoundment Informational Meeting was held at the National Mine Health and Safety Academy in Beckley, West Virginia. Fifteen presentations were given on key issues involved in the design and construction of dams associated with coal mining. The attendees were told that to improve the consistency among the plan reviewers, engineers from the Denver and Pittsburgh Technical Support Centers meet twice annually to discuss specific technical issues. It was soon discovered that the topics being discussed needed to be shared with anyone involved with coal waste dam design, construction, or inspection. The only way to accomplish that goal was through the issuance of Procedure Instruction Letters. The Letters present a consensus of engineering philosophy that could change over time. They do not present policy or carry the force of law. Currently, thirteen position papers have been disseminated and more will follow as the need arises. The individual paper were not even entered into the database.

  2. The long-term environmental impacts of the Mount Polley mine tailings spill, British Columbia, Canada

    Science.gov (United States)

    Byrne, Patrick; Hudson-Edwards, Karen; Macklin, Mark; Brewer, Paul; Bird, Graham; Williams, Richard

    2015-04-01

    On the 4th August 2014 a tailings impoundment failure at the Mount Polley gold and copper mine in British Columbia, Canada, released approximately 25 million m3 of solid and liquid waste into Hazeltine Creek, Quesnel Lake and Polley Lake. The sheer volume of the tailings released caused Haseltine Creek channel to expand from 2m to over 25m in width and Polley Lake water level to rise by 1.7m. The spill also removed trees in a 900 km2 corridor either side of Hazeltine Creek. Local residents and government officials have expressed serious concerns regarding the potential long-term effects on regional biodiversity, water security and to the livelihoods of First Nation communities. Among impoundment failures, the Mount Polley disaster is unique in that the solid tailings contain an unusual mixture of metal contaminants (arsenic, copper, gold, manganese, nickel, lead, vanadium). As particulate matter is the principal carrier of metal contaminants, the spilled tailings may reside in the regional soils and sediments for 1000s of years serving as a secondary source of pollution. The environmental risk posed by the spilled tailings is compounded by the location of the spill in a mountainous forested catchment, affected by severe winters with prominent spring snow melts that have the potential to remobilise very large quantities of spilled tailings. No data currently exist on the short- to long-term behaviour of these tailings in soils and sediments and the effects of the clean-up operations on their behaviour in this type of river environment. In this study, we adopt a multidisciplinary approach to determine the environmental and geomorphological impacts of the tailings spill. We have two specific objectives. (1) The physicochemical speciation and geochemical stability of spilled tailings will be characterised in surface and hyporheic sediments using bulk chemistry, mineralogical (XRD and SEM) and speciation methods (sequential extractions, electron microprobe analysis, XAS

  3. Uranium mill tailings: nuclear waste and natural laboratory for geochemical and radioecological investigations

    Science.gov (United States)

    Landa, Edward R.

    2004-01-01

    Uranium mill tailings (UMT) are a high volume, low specific activity radioactive waste typically disposed in surface impoundments. This review focuses on research on UMT and related earth materials during the past decade relevant to the assessment of: (1) mineral hosts of radionuclides; (2) the use of soil analogs in predicting long-term fate of radionuclides; (3) microbial and diagenetic processes that may alter radionuclide mobility in the surficial environment; (4) waste-management technologies to limit radionuclide migration; and (5) the impact of UMT on biota.

  4. 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

  5. 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

  6. 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

  7. The impact of unconfined mine tailings in residential areas from a mining town in a semi-arid environment: Nacozari, Sonora, Mexico.

    Science.gov (United States)

    Meza-Figueroa, Diana; Maier, Raina M; de la O-Villanueva, Margarita; Gómez-Alvarez, Agustín; Moreno-Zazueta, Alan; Rivera, Jacinto; Campillo, Alberto; Grandlic, Christopher J; Anaya, Ricardo; Palafox-Reyes, Juan

    2009-09-01

    Past mining activities in northern Mexico left a legacy of delerict landscapes devoid of vegetation and seasonal formation of salt efflorescence. Metal content was measured in mine tailings, efflorescent salts, soils, road dust, and residential soils to investigate contamination. Climatic effects such as heavy wind and rainfall events can have great impact on the dispersion of metals in semi-arid areas, since soils are typically sparsely vegetated. Geochemical analysis of this site revealed that even though total metal content in mine tailings was relatively low (e.g. Cu= 1000 mg kg(-1)), metals including Mn, Ba, Zn, and Cu were all found at significantly higher levels in efflorescence salts formed by evaporation on the tailings impoundment surface following the rainy season (e.g. Cu= 68,000 mg kg(-1)). Such efflorescent fine-grained salts are susceptible to wind erosion resulting in increased metal spread to nearby residential soils. Our results highlight the importance of seasonally dependent salt-formation and wind erosion in determining risk levels associated with potential inhalation or ingestion of airborne particulates originating from contaminated sites such as tailings impoundments. In low metal-content mine tailings located in arid and semi-arid environments, efflorescence salts could represent a human health risk and a challenge for plant establishment in mine tailings.

  8. The impact of unconfined mine tailings in residential areas from a mining town in a semi-arid environment: Nacozari, Sonora, Mexico

    Science.gov (United States)

    Meza-Figueroa, Diana; Maier, Raina M.; de la O-Villanueva, Margarita; Gómez-Alvarez, Agustín; Moreno-Zazueta, Alan; Rivera, Jacinto; Campillo, Alberto; Grandlic, Christopher; Anaya, Ricardo; Palafox-Reyes, Juan

    2009-01-01

    Past mining activities in northern Mexico left a legacy of delerict landscapes devoid of vegetation and seasonal formation of salt efflorescence. Metal content was measured in mine tailings, efflorescent salts, soils, road dust and residential soils to investigate contamination. Climatic effects such as heavy wind and rainfall events can have great impact on the dispersion of metals in semi-arid areas, since soils are typically sparsely vegetated. Geochemical analysis of this site revealed that even though total metal content in mine tailings was relatively low (e.g. Cu = 1000 mg kg-1), metals including Mn, Ba, Zn, and Cu were all found at significantly higher levels in efflorescence salts formed by evaporation on the tailings impoundment surface following the rainy season (e.g. Cu=68000 mg kg-1). Such efflorescent fine-grained salts are susceptible to wind erosion resulting in increased metal spread to nearby residential soils. Our results highlight the importance of seasonally dependent salt-formation and wind erosion in determining risk levels associated with potential inhalation or ingestion of airborne particulates originating from contaminated sites such as tailings impoundments. In low metal-content mine tailings located in arid and semi-arid environments, efflorescence salts could represent a human health risk and a challenge for plant establishment in mine tailings. PMID:19500816

  9. 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)

  10. Using Helicopter Electromagnetic Surveys to Identify Potential Hazards at Mine Waste Impoundments

    Energy Technology Data Exchange (ETDEWEB)

    Hammack, R.W.

    2008-01-01

    In July 2003, helicopter electromagnetic surveys were conducted at 14 coal waste impoundments in southern West Virginia. The purpose of the surveys was to detect conditions that could lead to impoundment failure either by structural failure of the embankment or by the flooding of adjacent or underlying mine works. Specifically, the surveys attempted to: 1) identify saturated zones within the mine waste, 2) delineate filtrate flow paths through the embankment or into adjacent strata and receiving streams, and 3) identify flooded mine workings underlying or adjacent to the waste impoundment. Data from the helicopter surveys were processed to generate conductivity/depth images. Conductivity/depth images were then spatially linked to georeferenced air photos or topographic maps for interpretation. Conductivity/depth images were found to provide a snapshot of the hydrologic conditions that exist within the impoundment. This information can be used to predict potential areas of failure within the embankment because of its ability to image the phreatic zone. Also, the electromagnetic survey can identify areas of unconsolidated slurry in the decant basin and beneath the embankment. Although shallow, flooded mineworks beneath the impoundment were identified by this survey, it cannot be assumed that electromagnetic surveys can detect all underlying mines. A preliminary evaluation of the data implies that helicopter electromagnetic surveys can provide a better understanding of the phreatic zone than the piezometer arrays that are typically used.

  11. Tidal management sffects sub-adult fish assemblages in impounded South Carolina Marshes

    Science.gov (United States)

    Carswell, Ben L.; Peterson, James T.; Jennings, Cecil A.

    2015-01-01

    In coastal South Carolina, most impounded marshes are managed for waterfowl; fewer are managed for fishes. Tidal control is central to each strategy but raises concerns that nursery function could be impaired. This research examined the assemblage composition of fishes during early-life stages. We sampled two impoundments of each management type monthly in 2008 and 2009. We used light traps to collect 61,527 sub-adult fish representing 21 species and 16 families and push nets to collect 12,670 sub-adult fish representing 13 species and 11 families. The effective number of species detected at larval stage in “fish” impoundments (summer mean = 2.52 ± 0.20, winter mean = 2.02 ± 0.66) was greater than in “waterfowl” impoundments (summer mean = 1.27 ± 0.14, winter mean = 1.06 ± 0.09); CI = 90 %. Species richness did not differ between management types, but hierarchical linear models predicted differences in assemblage composition. These findings underscore the importance of frequent water exchange for maintaining diverse assemblages of early-life-stage fishes in marsh impoundments.

  12. Distribution and migration of pesticide residues in mosquito control impoundments St. Lucie County, Florida, USA

    Science.gov (United States)

    Parkinson, R. W.; Wang, T. C.; White, J. R.; David, J. R.; Hoffman, M. E.

    1993-09-01

    This project was designed to: (1) document the distribution and migration of organochlorine pesticide residues within marsh substrates of 18 St. Lucie County mosquito control impoundments located along the Indian River Lagoon estuary, and (2) evaluate the impact of water management techniques on residue mobility. Our results indicate that detectible concentrations of organochlorine compounds, applied between the late 1940s and early 1950s, are present in 16 of the 18 St. Lucie County mosquito control impoundments. These compounds are primarily restricted to the surficial, organic-rich wetland sediment, which, based upon geotechnical analysis, was exposed to the atmosphere at a time when the impoundments were subjected to pesticide treatment. Contaminated sediments are present below the surficial, organic-rich layer, suggesting that some vertical migration of pesticides has occurred. It is unlikely that leaching associated with the downward percolation of impounded water was responsible for this migration as pesticide residues were never detected within the in situ pore waters. An alternative explanation is that biological processes (e.g., rooting, burrowing) facilitated the downward flux of organochlorine compounds into sediment horizons not subjected to direct treatment. Eighty-eight surface water samples obtained from two impoundments subjected to contrasting water management techniques were analyzed for pesticide content. None of the surficial water samples collected in association with these impoundments contained detectible concentrations of organochlorine compounds. These samples were unfiltered and contained as much as 25 mg/1 of particulate organic matter. This suggests that the currently preferred management technique (RIM), which is designed to maintain water quality, limit mosquito production, and provide for ecological continuity, does not hydraulically mobilize pesticide residues into the Indian River Lagoon estuary.

  13. The Role of Small Impoundments on Flow Alteration Within River Networks

    Science.gov (United States)

    Brogan, C. O.; Keys, T.; Scott, D.; Burgholzer, R.; Kleiner, J.

    2017-12-01

    Numerous water quality and quantity models have been established to illustrate the ecologic and hydrologic effects of large reservoirs. Smaller, unregulated ponds are often assumed to have a negligible impact on watershed flow regimes even though they overwhelmingly outnumber larger waterbodies. Individually, these small impoundments impart merely a fraction of the flow alteration larger reservoirs do; however, a network of ponds may act cumulatively to alter the flow regime. Many models have attempted to study smaller impoundments but rely on selectively available rating curves or bathymetry surveys. This study created a generalized process to model impoundments of varying size across a 58 square mile watershed exclusively using satellite imagery and publicly available information as inputs. With information drawn from public Army Corps of Engineers databases and LiDAR surveys, it was found that impoundment surface and drainage area served as useful explanatory variables, capable of predicting both pond bathymetry and outlet structure area across the 37 waterbodies modeled within the study area. Working within a flow routing model with inputs from the Chesapeake Bay HSPF model and verified with USGS gauge data, flow simulations were conducted with increasing number of impoundments to quantify how small ponds affect the overall flow regime. As the total impounded volume increased, simulations showed a notable reduction in both low and peak flows. Medium-sized floods increased as the network of ponds and reservoirs stabilized the catchment's streamflow. The results of this study illustrate the importance of including ponded waters into river corridor models to improve downstream management of both water quantity and quality.

  14. Revegetation/rock cover for stabilization of inactive uranium mill tailings disposal sites

    International Nuclear Information System (INIS)

    Beedlow, P.A.; McShane, M.C.; Cadwell, L.L.

    1982-07-01

    Pacific Northwest Laboratory is developing design and performance guidelines for surface stabilization of inactive uranium mill tailings. In this work, vegetation and rock covers are being evaluated for maintaining long-term integrity of impoundment systems. Methods are being developed to estimate erosion rates associated with rock and/or vegetation covers, and to determine the effects of surface treatments on soil moisture. Interactions between surface treatments and barriers (radon and biological) are being studied as well. The product will be a set of guidelines to aid in designing surface covers. This report presents the status of this program and a discussion of considerations pertinent to the application of surface covers to tailings. Test plots located in Grand Junction, Colorado and Waterflow, New Mexico are being used to study: (1) the interactions between vegetation and radon and biological barriers, (2) the effects of surface covers on soil moisture, and (3) the effects of rock covers on vegetation

  15. Effect of ship locking on sediment oxygen uptake in impounded rivers

    DEFF Research Database (Denmark)

    Lorke, A.; McGinnis, D. F.; Maeck, A.

    2012-01-01

    In the majority of large river systems, flow is regulated and/or otherwise affected by operational and management activities, such as ship locking. The effect of lock operation on sediment-water oxygen fluxes was studied within a 12.9 km long impoundment at the Saar River (Germany) using eddy......-correlation flux measurements. The continuous observations cover a time period of nearly 5 days and 39 individual locking events. Ship locking is associated with the generation of surges propagating back and forth through the impoundment which causes strong variations of near-bed current velocity and turbulence...

  16. A two-reagent neutralization scheme for controlling the migration of contaminants from a uranium mill tailing disposal pond

    International Nuclear Information System (INIS)

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

    1985-01-01

    Techniques for reducing contaminant migration from tailings liquor impoundments and evaporation ponds are being investigated by the Pacific Northwest Laboratory as part of the Nuclear Regulatory Commission's Uranium Research and Recovery Program. Building upon previous studies investigating single-reagent neutralization, laboratory experiments were conducted to evaluate the performance of a two-reagent neutralization scheme for the treatment of acidic uranium mill tailings liquors. Acidic tailings liquor, pH 3 neutralization to pH 4.0 followed by continued neutralization with lime to pH 7.3, resulted in the highest solution quality with respect to the Environmental Protection Agency's water quality guidelines. Furthermore, the two-reagent neutralization scheme is the most cost-effective treatment procedure tested to date

  17. Long-term stability of earthen materials in contact with acidic tailings solutions

    International Nuclear Information System (INIS)

    Peterson, S.R.; Erikson, R.L.; Gee, G.W.

    1982-11-01

    The objectives of the studies documented in this report were to use experimental and geochemical computer modeling tools to assess the long-term environmental impact of leachate movement from acidic uranium mill tailings. Liner failure (i.e., an increase in the permeability of the liner material) was not found to be a problem when various acidic tailings solutions leached through liner materials for periods up to 3 years. On the contrary, materials that contained over 30% clay showed a decrease in permeability with time in the laboratory columns. The high clay materials tested appear suitable for lining tailings impoundment ponds. The decreases in permeability are attributed to pore plugging resulting from the precipitation of minerals and solids. This precipitation takes place due to the increase in pH of the tailings solution brought about by the buffering capacity of the soil. Geochemical modeling predicts, and x-ray characterization confirms, that precipitation of solids from solution is occurring in the acidic tailings solution/liner interactions studied. In conclusion the same mineralogical changes and contaminant reactions predicted by geochemical modeling and observed in laboratory studies were found at a drained evaporation pond (Lucky Mc in Wyoming) with a 4 year history of acid attack

  18. Probabilistic assessment of the long-term performance of the Panel Mine tailings area

    International Nuclear Information System (INIS)

    Balins, J.K.; Davis, J.B.; Payne, R.A.

    1994-01-01

    Rio Algom's Panel Uranium Mine originally operated between 1958 and 1961. It was reactivated in 1979 and operated continuously until 1990. In all, the mine produced about 14 million tons of potentially acid generating, low level radioactive uranium tailings; about 5% pyrite (by weight) with less than 0.1% U 3 O 8 . The tailings area consists of two rock rimmed basins. Topographic lows around the perimeter are closed by a total of six containment dams. To minimize the acid generating potential within the tailings, a decommissioning plan to flood the impounded tailings is being implemented. The anticipated performance of engineered structures (dams, spillways, channels, etc.) and the flooded tailings concept, over time periods in the order of thousands of years, have been addressed using probabilistic methods, based on subjective probability distributions consistent with available site specific information. The probable costs associated with long-term inspection and maintenance of the facility, as well as the probable costs and environmental consequences (e.g. tailings releases) associated with potential dam failures due to disruptive events such as floods, droughts and earthquakes were determined using a probabilistic model which consists of five, essentially independent, sub-models: a Maintenance Model, an Earthquake Response Model, a Flood Response Model, a Drought Model and an Integration Model. The principal conclusion derived from this assessment is that, for a well designed, constructed and maintained facility, there is very little likelihood that water and/or tailings solids will be released as a result of a containment dam failure; annual probability of the order of 10 -6 . Failure to maintain the facility over the long-term significantly increases the likelihood of dam failure with resultant release of water and suspended tailings solids

  19. Assessing Resiliency in a Large Lake Receiving Mine Tailings Waste: Impacts of Major Environmental Disturbance.

    Science.gov (United States)

    Petticrew, Ellen; Owens, Philip; Albers, Sam

    2016-04-01

    On 4th August 2014, the tailings impoundment of the Mount Polley copper and gold mine in British Columbia failed. Material from the impoundment (surface area = 2.7 km2) flowed into nearby Polley Lake and Hazeltine Creek, before discharging into Quesnel Lake, a large (ca. 100 km long, >500 m deep), relatively pristine lake. Initial estimates suggest that approximately 25 Mm3 of tailings (water and solids) and eroded soils and surficial materials from Hazeltine Creek were delivered to Quesnel Lake, raising the lake by 7.7 cm. Much of this material was deposited at the bottom of Quesnel Lake but a plume of fine-grained sediment (D50 of ca. 1 μm) remained suspended in the water column. The impact of the distribution of this sediment was monitored over the next 15 months using water column profiling for temperature, conductivity, fluorescence and turbidity with depth. The plume movement was regulated by natural processes associated with the physical limnology of this large fjord lake, specifically, seiche events which transferred suspended particles both up-lake, against the flow regime, and down-lake into the Quesnel River. Samples of lake water and bottom sediment taken from the impacted area show elevated levels of total metals and other elements, which may have important ecosystem implications in this watershed. Indeed, the breach occurred at a time when a peak run of sockeye salmon were returning to their natal streams in the Quesnel basin. Zooplankton sampling for metals was initiated in fall 2014 to determine up take of metals into the food web. This poster describes the failure of the impoundment dam and presents results of sampling the aquatic environment over the first fifteen months of impact.

  20. Uranium tailings in Canada

    International Nuclear Information System (INIS)

    Boulden, R.S.; Bragg, K.

    1982-01-01

    The last few years have produced significant changes in the way uranium tailings are managed in Canada. This is due both to the development of new technology and to changes in regulatory approach. The interrelationships between these two areas are examined with particular attention paid to the long term and the development of close-out criteria. New technological initiatives are examined including dry placement techniques, pit disposal and deep lake disposal

  1. Partitions, Compartments and Portals: Cave Development in internally impounded karst masses.

    Directory of Open Access Journals (Sweden)

    Osborne R. Armstrong L.

    2005-07-01

    Full Text Available Dykes and other vertical bodies can act as aquicludes within bodies of karst rock. These partitions separate isolated bodies of solublerock called compartments. Speleogenetically each compartment will behave as a small impounded-karst until the partition becomesbreached. Breaches through partitions, portals, allow water, air and biota including humans to pass between sections of caves thatwere originally isolated.

  2. Effects of increased summer flooding on nitrogen dynamics in impounded mangroves

    NARCIS (Netherlands)

    Verhoeven, Jos T A; Laanbroek, Hendrikus J; Rains, Mark C; Whigham, Dennis F

    2014-01-01

    Mangroves are important for coastal protection, carbon sequestration and habitat provision for plants and animals in the tropics and subtropics. Mangroves are threatened by habitat destruction and sea level rise, but management activities such as impounding for mosquito control can also have

  3. Evaluation of Co and Cr mobility in soil profiles collected in a scrapyard of impounded vehicles

    International Nuclear Information System (INIS)

    Lange, Camila N.; Figueiredo, Ana Maria G.; Enzweiler, Jacinta

    2015-01-01

    The number of motor vehicles in urban environments has increased dramatically in the past years. As a result, so has the number of impounded and end-of-life vehicles. Car wastes can have a very high metal content, which can cause important environmental impacts to the soil where these vehicles are kept. Most Brazilian vehicle impound scrapyards are currently operating at their maximum capacity and soils may have become contaminated by past or current vehicle handling practices. Most of these areas do not present an impermeable surface. The level of soil contamination with heavy metals depends on the type of soil, climate and management practices. Metals, such as Co and Cr, that are present in many auto-parts, may be considered potentially toxic elements in these areas. The aim of this study was to evaluate Co and Cr levels and behavior in soil profiles located in a scrapyard of impounded vehicles of Ribeirao Pires-SP city. For this purpose, samples from distinct horizons of three soil profiles were collected. Element concentrations were determined by Instrumental Neutron Activation Analysis (INAA). Soil parameters such as pH, organic matter content and clay, silt and sand percentage were also determined. The obtained data were statistically analyzed in order to establish correlations between elemental concentrations and the impounded vehicles scrapyard soil. Soil acidity showed to be the most remarkable property for Cr and Co mobility through soil profile. (author)

  4. 40 CFR 63.942 - Standards-Surface impoundment floating membrane cover.

    Science.gov (United States)

    2010-07-01

    ... operations, and form a continuous barrier over the entire surface area of the liquid. (2) The cover shall be... closure device in the closed position, as applicable. (ii) To remove accumulated sludge or other residues from the bottom of surface impoundment. (2) Opening of a spring-loaded pressure-vacuum relief valve...

  5. Application of carbon isotopes to detect seepage out of coalbed natural gas produced water impoundments

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Shikha, E-mail: shikha.sharma@mail.wvu.edu [Department of Geology and Geography, West Virginia University, Morgantown, WV 26506 (United States); Baggett, Joshua K. [Department of Ecosystem Science and Management, Texas A and M University, College Station, 77843 2126 (United States)

    2011-08-15

    Highlights: > Coalbed natural gas extraction results in large amount of produced water. > Risk of deterioration of ambient water quality. > Carbon isotope natural tracer for detecting seepage from produced water impoundments. - Abstract: Coalbed natural gas (CBNG) production from coal bed aquifers requires large volumes of produced water to be pumped from the subsurface. The produced water ranges from high quality that meets state and federal drinking water standards to low quality due to increased salinity and/or sodicity. The Powder River Basin of northeastern Wyoming is a major coalbed natural gas producing region, where water quality generally decreases moving from the southeastern portion of the basin towards the center. Most produced water in Wyoming is disposed into impoundments and other surface drainages, where it may infiltrate into shallow groundwater. Groundwater degradation caused by infiltration of CBNG produced water holding impoundments into arid, soluble salt-rich soils is an issue of immense importance because groundwater is a major source for stock water, irrigation, and drinking water for many small communities in these areas. This study examines the potential of using stable C isotope signatures of dissolved inorganic C ({delta}{sup 13}C{sub DIC}) to track the fate of CBNG produced water after it is discharged into the impoundments. Other geochemical proxies like the major cations and major anions were used in conjunction with field water quality measurements to understand the geochemical differences between CBNG produced waters and ambient waters in the study area. Samples were collected from the CBNG discharge outfalls, produced water holding impoundments, and monitoring wells from different parts of the Powder River Basin and analyzed for {delta}{sup 13}C{sub DIC}. The CBNG produced waters from outfalls and impoundments have positive {delta}{sup 13}C{sub DIC} values that fall within the range of +12 per mille to +22 per mille, distinct from

  6. Physicochemical and mineralogical characterization of Musina mine copper and New Union gold mine tailings: Implications for fabrication of beneficial geopolymeric construction materials

    Science.gov (United States)

    Gitari, M. W.; Akinyemi, S. A.; Thobakgale, R.; Ngoejana, P. C.; Ramugondo, L.; Matidza, M.; Mhlongo, S. E.; Dacosta, F. A.; Nemapate, N.

    2018-01-01

    The mining industries in South Africa generates huge amounts of mine waste that includes tailings; waste rocks and spoils. The tailings materials are dumped in surface impoundments that turn to be sources of hazards to the environment and the surrounding communities. The main environmental hazards posed by these tailings facilities are associated with their chemical constituents. Exposure to chemical constituents can occur through windblown dust, erosion to surface water bodies, inhalation by human beings and animals and through bioaccumulation and bio magnification by plants. Numerous un-rehabilitated tailings dumps exist in Limpopo province of South Africa. The communities found around these mines are constantly exposed to the environmental hazards posed by these tailing facilities. Development of a cost-effective technology that can beneficially utilize these tailings can reduce the environmental hazards and benefit the communities. This paper presents the initial evaluation of the copper and gold mine tailings in Limpopo, South Africa with a view to assessing the suitability of conversion into beneficial geopolymeric materials. Copper tailings leachates had alkaline pH (7.34-8.49) while the gold tailings had acidic pH. XRD confirmed presence of aluminosilicate minerals. Geochemical fractionation indicates that majority of the major and trace species are present in residual fraction. A significant amount of Ca, Cu and K was available in the mobile fraction and is expected to be released on tailings contacting aqueous solutions. Results from XRF indicates the tailings are rich in SiO2, Al2O3 and CaO which are the main ingredients in geopolymerization process. The SiO2/Al2O3 ratios indicates the tailings would require blending with Al2O3 rich feedstock for them to develop maximum strength. Moreover, the tailings have particle size in the range of fine sand which indicates potential application as aggregates in conventional brick manufacture.

  7. 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.

  8. 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, and sup......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...

  9. Interfacial stability of soil covers on lined surface impoundments

    International Nuclear Information System (INIS)

    Mitchell, D.H.; Gates, T.E.

    1986-04-01

    The factors affecting the interfacial stability of soil covers on geomembranes were examined to determine the maximum stable slopes for soil cover/geomembrane systems. Several instances of instability of soil covers on geomembranes have occurred at tailings ponds, leaving exposed geomembranes with the potential for physical ddamage and possibly chemical and ultraviolet degradation. From an operator's viewpoint, it is desirable to maximize the slope of lined facilities in order to maximize the volume-to-area ratio; however, the likelihood for instability also increases with increasing slope. Frictional data obtained from direct shear tests are compared with stability data obtained using a nine-square-meter (m 2 ) engineering-scale test stand to verify that direct shear test data are valid in slope design calculations. Interfacial frictional data from direct shear tests using high-density polyethylene and a poorly graded sand cover agree within several degrees with the engineering-scale tests. Additional tests with other soils and geomembranes are planned. The instability of soil covers is not always an interfacial problem; soil erosion and limited drainage capacity are additional factors that must be considered in the design of covered slopes. 7 refs., 5 figs., 2 tabs

  10. 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.

  11. Injurious tail biting in pigs

    DEFF Research Database (Denmark)

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

    2014-01-01

    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...... and prevention of tail damage. However, there is a lack of scientific studies on how best to respond to outbreaks: the effectiveness of, for example, removing biters and/or bitten pigs, increasing enrichment, or applying substances to tails should be investigated. Finally, some breeding companies are exploring...

  12. The Impact of Impoundment on Mercury Bioaccumulation in Fish Downstream from a Newly Constructed Reservoir, Wujiang River, Southwest China.

    Science.gov (United States)

    Li, Sixin; Zhou, Lianfeng; Chang, Jianbo; Yang, Zhi; Hu, Juxiang; Hongjun, Wang

    2017-11-01

    Mercury concentrations in fish were investigated downstream from a newly impounded subtropical reservoir in August 2008. After 6-7 months of reservoir impoundment, mean mercury concentration in fish from downstream is significantly increased by 1.9 times. Not only carnivorous fish but also benthic fish had significantly higher total mercury concentrations than others. No significant correlation was found between total mercury concentrations and body length or weight of 13 fish species. Compared with the pre-impoundment, total mercury in fish from downstream is significantly increased by reservoir impoundment, but the increased rate is lower than those in subarctic and temperate areas. Fish samples surpassed the Chinese hygienic standard for tolerances of mercury in foods increased by 4.3%. More attention should be given to fish mercury levels from downstream sites to prevent possible adverse effects on the health of local people.

  13. Technical work plan for Surface Impoundments Operable Unit engineering support studies

    International Nuclear Information System (INIS)

    1995-11-01

    This document provides a comprehensive work plan which, when utilized as a data collection guide for field activities, will provide the necessary information required to complete a report on geotechnical properties of the sediments contained in the Surface Impoundments Operable Unit at Oak Ridge National Laboratory in Oak Ridge, Tennessee. Detailed guidance is provided for the following activities: collection of samples from the impoundments; compressive strength testing of the raw sediments; compressive strength testing of the structurally modified (lime and cement additives) sediments; testing for sediment physical properties and settling rates; testing for sediment dewatering characteristics; testing for radiation activity during the field work; testing for polymer additions that may enhance settling. The work plan additionally provides guidance and examples for the preparation of documents necessary to establish readiness for safe and satisfactory performance of the field activities. An outline for the format requested for a report of these data is also provided

  14. Restoration of Tidal Flow to Impounded Salt Marsh Exerts Mixed Effect on Leaf Litter Decomposition

    Science.gov (United States)

    Henry, B. A.; Schade, J. D.; Foreman, K.

    2015-12-01

    Salt marsh impoundments (e.g. roads, levees) disconnect marshes from ocean tides, which impairs ecosystem services and often promotes invasive species. Numerous restoration projects now focus on removing impoundments. Leaf litter decomposition is a central process in salt marsh carbon and nutrient cycles, and this study investigated the extent to which marsh restoration alters litter decomposition rates. We considered three environmental factors that can potentially change during restoration: salinity, tidal regime, and dominant plant species. A one-month field experiment (Cape Cod, MA) measured decay of litter bags in impounded, restored, and natural marshes under ambient conditions. A two-week lab experiment measured litter decay in controlled incubations under experimental treatments for salinity (1ppt and 30 ppt), tidal regime (inundated and 12 hr wet-dry cycles), and plant species (native Spartina alterniflora and invasive Phragmites australis). S. alterniflora decomposed faster in situ than P. australis (14±1.0% mass loss versus 0.74±0.69%). Corroborating this difference in decomposition, S. alterniflora supported greater microbial respiration during lab incubation, measured as CO2 flux from leaf litter and biological oxygen demand of water containing leached organic matter (OM). However, nutrient analysis of plant tissue and leached OM show P. australis released more nitrogen than S. alterniflora. Low salinity treatments in both lab and field experiments decayed more rapidly than high salinity treatments, suggesting that salinity inhibited microbial activity. Manipulation of inundation regime did not affect decomposition. These findings suggest the reintroduction of tidal flow to an impounded salt marsh can have mixed effects; recolonization by the native cordgrass could supply labile OM to sediment and slow carbon sequestration, while an increase in salinity might inhibit decomposition and accelerate sequestration.

  15. Effects of river impoundment on ecosystem services of large tropical rivers: embodied energy and market value of artisanal fisheries.

    Science.gov (United States)

    Hoeinghaus, David J; Agostinho, Angelo A; Gomes, Luiz C; Pelicice, Fernando M; Okada, Edson K; Latini, João D; Kashiwaqui, Elaine A L; Winemiller, Kirk O

    2009-10-01

    Applying the ecosystem services concept to conservation initiatives or in managing ecosystem services requires understanding how environmental impacts affect the ecology of key species or functional groups providing the services. We examined effects of river impoundments, one of the leading threats to freshwater biodiversity, on an important ecosystem service provided by large tropical rivers (i.e., artisanal fisheries). The societal and economic importance of this ecosystem service in developing countries may provide leverage to advance conservation agendas where future impoundments are being considered. We assessed impoundment effects on the energetic costs of fisheries production (embodied energy) and commercial market value of the artisanal fishery of the Paraná River, Brazil, before and after formation of Itaipu Reservoir. High-value migratory species that dominated the fishery before the impoundment was built constituted a minor component of the contemporary fishery that is based heavily on reservoir-adapted introduced species. Cascading effects of river impoundment resulted in a mismatch between embodied energy and market value: energetic costs of fisheries production increased, whereas market value decreased. This was partially attributable to changes in species functional composition but also strongly linked to species identities that affected market value as a result of consumer preferences even when species were functionally similar. Similar trends are expected in other large tropical rivers following impoundment. In addition to identifying consequences of a common anthropogenic impact on an important ecosystem service, our assessment provides insight into the sustainability of fisheries production in tropical rivers and priorities for regional biodiversity conservation.

  16. A Test of the Serial Discontinuity Concept Using Pre- and Post-Impoundment Data: do Ecosystems Recover?

    Science.gov (United States)

    Powell, H.; Jackson, L.; Culp, J.

    2005-05-01

    Many rivers are influenced by human-made impoundments that alter natural habitat. Changes in habitat hold potential consequences for biotic community structure and ecosystem function. The serial discontinuity concept (SDC), however, predicts that riverine process and function will recover downstream from an impoundment via tributary inputs. Unfortunately, rivers rarely exist in the context assumed by the SDC. Often, watersheds include multiple impoundments and other flow-altering structures. We present preliminary data and future research goals to investigate the changes in riverine habitat and benthic community structure before and after impoundment over 400 km of the Oldman River, southern Alberta, Canada. Habitat characteristics and benthic invertebrate abundance and community structure prior to dam construction were tested against post-impoundment data. Results indicate that 15 years after impoundment, flow and sediment regimes have not recovered. There is a significant decline in discharge during high flow periods below the dam and a pattern of decreased sediment transport and increased retention below the dam. Initial results have serious implications to benthic invertebrates, many of which require cobble substrates for colonization. The preliminary results on habitat alteration below the Oldman Dam do not support the predictions of the SDC.

  17. The geo-environmental design of a coal refuse impoundment in Illinois

    International Nuclear Information System (INIS)

    Ripp, B.J.

    1997-01-01

    The coal refuse impoundment discussed was one of the first permitted under new regulatory standards within the State of Illinois. The new standards go beyond the geotechnial stability of the structure and must address the groundwater quality of the area and the impact of the impoundment on the groundwater system. The geotechnial design of the coal refuse impoundment dam and associated structures had its own particular challenges such as: 1) the construction of the structure over mined workings; 2) the close proximity of seismically active fault zones; and 3) the embankment configuration being controlled by the material balance of the mine refuse. The implementation of the groundwater protection plan included: 1) incorporating the groundwater quality standards and sampling protocols of several state agencies while the standards were being drafted; 2) sampling of the potential sources of groundwater impact; 3) establishing background levels; and 4) establishing the groundwater class. An initial groundwater transport model was developed and used as the basis for recommending a groundwater monitoring design in place of constructing a soil or synthetic liner. 15 refs., 2 figs., 3 tabs

  18. Mercury's Dynamic Magnetic Tail

    Science.gov (United States)

    Slavin, James A.

    2010-01-01

    The Mariner 10 and MESSENGER flybys of Mercury have revealed a magnetosphere that is likely the most responsive to upstream interplanetary conditions of any in the solar system. The source of the great dynamic variability observed during these brief passages is due to Mercury's proximity to the Sun and the inverse proportionality between reconnection rate and solar wind Alfven Mach number. However, this planet's lack of an ionosphere and its small physical dimensions also contribute to Mercury's very brief Dungey cycle, approx. 2 min, which governs the time scale for internal plasma circulation. Current observations and understanding of the structure and dynamics of Mercury's magnetotail are summarized and discussed. Special emphasis will be placed upon such questions as: 1) How much access does the solar wind have to this small magnetosphere as a function of upstream conditions? 2) What roles do heavy planetary ions play? 3) Do Earth-like substorms take place at Mercury? 4) How does Mercury's tail respond to extreme solar wind events such coronal mass ejections? Prospects for progress due to advances in the global magnetohydrodynamic and hybrid simulation modeling and the measurements to be taken by MESSENGER after it enters Mercury orbit on March 18, 2011 will be discussed.

  19. Surface water hydrology considerations in predicting radon releases from water-covered areas of uranium tailings ponds

    International Nuclear Information System (INIS)

    Nielson, K.K.; Rogers, V.C.

    1986-01-01

    In a recent study for EPA on radon releases from active uranium mills, the authors examined the potential for advective transport of radon through tailings pond waters along with other radon sources in the mill environment. This paper summarizes the parts of the study that dealt with radon releases from the tailings pond area, and discusses the nature and mechanisms of the radon releases from water-covered areas. A reference tailings impoundment is described according to several distinct physical regions, and the conditions affecting radon transport in each are described. Since radon transport through ponded water has not previously been modeled in detail, simple laboratory experiments were conducted to approximate the characteristic transport parameters. The results of these experiments were then used with parameters describing the tailings pond to assess the overall magnitude of radon release expected from the water-covered pond region. The significance of radon releases from the water-covered areas was estimated by comparison to radon fluxes from other, exposed tailings surfaces

  20. The 27 May 1937 catastrophic flow failure of gold tailings at Tlalpujahua, Michoacán, México

    Science.gov (United States)

    Macías, J. L.; Corona-Chávez, P.; Sanchéz-Núñez, J. M.; Martínez-Medina, M.; Garduño-Monroy, V. H.; García-Tenorio, F.; Cisneros-Máximo, G.

    2014-08-01

    On 27 May 1937, after one week of sustained heavy rainfall, a voluminous flood caused the death of at least 300 people and the destruction of the historic El Carmen church and several neighborhoods in the mining region of Tlalpujahua, Michoacán, central Mexico. This destructive flood was triggered by the breaching of the impoundment of the Los Cedros tailings and the sudden release of 16 Mt of water-saturated waste materials. The muddy silty flood, moving at estimated speeds of 20-25 m s-1, was channelized along the Dos Estrellas and Tlalpujahua drainages and devastated everything along its flow path. After advancing 2.5 km downstream, the flood slammed into El Carmen church and surrounding houses at estimated speeds of ~7 m s-1, destroying many of construction walls and covering the church floor with ~2 m of mud and debris. Eyewitness accounts and newspaper articles, together with analysis of archived photographic materials, indicated that the flood consisted of three muddy pulses. This interpretation is confirmed and extended by the results of our geological investigations during 2013 and 2014. Stratigraphic relations and granulometric data for selected proximal and distal samples show that the flood behaved as a hyperconcentrated flow along most of its trajectory. Even though premonitory signs of possible impoundment failure were reported days before the flood, and people living downstream were alerted, authorities ordered no evacuations or other mitigative actions. The catastrophic flood at Tlalpujahua provides a well-documented, though tragic, example of impoundment breaching of a tailings dam caused by the combined effects of intense rainfall, dam weakness, and inadequate emergency-management protocols - unfortunately an all too common case-scenario for most of the world's mining regions.

  1. Pre- and post-impoundment nitrogen in the lower Missouri River

    Science.gov (United States)

    Blevins, Dale W.; Wilkison, Donald H.; Niesen, Shelley L.

    2013-01-01

    Large water-sample sets collected from 1899 through 1902, 1907, and in the early 1950s allow comparisons of pre-impoundment and post-impoundment (1969 through 2008) nitrogen concentrations in the lower Missouri River. Although urban wastes were not large enough to detectably increase annual loads of total nitrogen at the beginning of the 20th century, carcass waste, stock-yard manure, and untreated human wastes measurably increased ammonia and organic-nitrogen concentrations during low flows. Average total-nitrogen concentrations in both periods were about 2.5 mg/l, but much of the particulate-organic nitrogen, which was the dominant form of nitrogen around 1900, has been replaced by nitrate. This change in speciation was caused by the nearly 80% decrease in suspended-sediment concentrations that occurred after impoundment, modern agriculture, drainage of riparian wetlands, and sewage treatment. Nevertheless, bioavailable nitrogen has not been low enough to limit primary production in the Missouri River since the beginning of the 20th century. Nitrate concentrations have increased more rapidly from 2000 through 2008 (5 to 12% per year), thus increasing bioavailable nitrogen delivered to the Mississippi River and affecting Gulf Coast hypoxia. The increase in nitrate concentrations with distance downstream is much greater during the post-impoundment period. If strategies to decrease total-nitrogen loads focus on particulate N, substantial decreases will be difficult because particulate nitrogen is now only 23% of total nitrogen in the Missouri River. A strategy aimed at decreasing particulates also could further exacerbate land loss along the Gulf of Mexico, which has been sediment starved since Missouri River impoundment. In contrast, strategies or benchmarks aimed at decreasing nitrate loads could substantially decrease nitrogen loadings because nitrates now constitute over half of the Missouri's nitrogen input to the Mississippi. Ongoing restoration and creation

  2. Monticello Mill Tailings Site, Operable Unit lll, Annual Groundwater Report, May 2015 Through April 2016

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Jason [USDOE Office of Legacy Management (LM), Washington, DC (United States); Smith, Fred [Navarro Research and Engineering, Oak Ridge, TN (United States)

    2016-10-01

    This report provides the annual analysis of water quality restoration progress, cumulative through April 2016, for Operable Unit (OU) III, surface water and groundwater, of the U.S. Department of Energy (DOE) Office of Legacy Management (LM) Monticello Mill Tailings Site (MMTS). The MMTS is a Comprehensive Environmental Response, Compensation, and Liability Act National Priorities List site located in and near the city of Monticello, San Juan County, Utah. MMTS comprises the 110-acre site of a former uranium- and vanadium-ore-processing mill (mill site) and 1700 acres of surrounding private and municipal property. Milling operations generated 2.5 million cubic yards of waste (tailings) from 1942 to 1960. The tailings were impounded at four locations on the mill site. Inorganic constituents in the tailings drained from the impoundments to contaminate local surface water (Montezuma Creek) and groundwater in the underlying alluvial aquifer. Mill tailings dispersed by wind and water also contaminated properties surrounding and downstream of the mill site. Remedial actions to remove and isolate radiologically contaminated soil, sediment, and debris from the former mill site, Operable Unit I (OU I), and surrounding properties (OU II) were completed in 1999 with the encapsulation of the wastes in an engineered repository located on DOE property 1 mile south of the former mill site. This effectively removed the primary source of groundwater contamination; however, contamination of groundwater and surface water remains within OU III at levels that exceed water quality protection standards. Uranium is the primary contaminant of concern (COC). LM implemented monitored natural attenuation with institutional controls as the OU III remedy in 2004. Because groundwater restoration proceeded more slowly than expected and did not meet performance criteria established in the OU III Record of Decision (June 2004), LM implemented a contingency action in 2009 by an Explanation of

  3. Tails, Fears and Risk Premia

    DEFF Research Database (Denmark)

    Bollerslev, Tim; Todorov, Victor

    We show that the compensation for rare events accounts for a large fraction of the equity and variance risk premia in the S&P 500 market index. The probability of rare events vary significantly over time, increasing in periods of high market volatility, but the risk premium for tail events cannot...... solely be explained by the level of the volatil- ity. Our empirical investigations are essentially model-free. We estimate the expected values of the tails under the statistical probability measure from "medium" size jumps in high-frequency intraday prices and an extreme value theory approximation...... for the corresponding jump tail density. Our estimates for the risk-neutral expectations are based on short maturity out-of-the money options and new model-free option implied variation measures explicitly designed to separate the tail probabilities. At a general level, our results suggest that any satisfactory...

  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...... it is not known, what the prevalence would have been had the pigs not been tail docked. The aim of this study was to compare the prevalence of tail lesions between docked and undocked pigs in a conventional piggery in Denmark with very low prevalence of tail biting among tail docked pigs. The study included 1922...... that housing pigs with intact tails in conventional herds with very low prevalence of tail biting among tail docked pigs, will increase the prevalence of pigs with tail lesions considerably, and pig producers will need more hospital pens. Abattoir data indicate that tail biting remarks from meat inspection...

  5. Infiltration from an impoundment for coal-bed natural gas, Powder River Basin, Wyoming: Evolution of water and sediment chemistry

    Science.gov (United States)

    Healy, R.W.; Rice, C.A.; Bartos, T.T.; McKinley, M.P.

    2008-01-01

    Development of coal-bed natural gas (CBNG) in the Powder River Basin, Wyoming, has increased substantially in recent years. Among environmental concerns associated with this development is the fate of groundwater removed with the gas. A preferred water-management option is storage in surface impoundments. As of January 2007, permits for more than 4000 impoundments had been issued within Wyoming. A study was conducted on changes in water and sediment chemistry as water from an impoundment infiltrated the subsurface. Sediment cores were collected prior to operation of the impoundment and after its closure and reclamation. Suction lysimeters were used to collect water samples from beneath the impoundment. Large amounts of chloride (12,300 kg) and nitrate (13,500 kg as N), most of which accumulated naturally in the sediments over thousands of years, were released into groundwater by infiltrating water. Nitrate was more readily flushed from the sediments than chloride. If sediments at other impoundment locations contain similar amounts of chloride and nitrate, impoundments already permitted could release over 48 x 106 kg of chloride and 52 x 106 kg of nitrate into groundwater in the basin. A solute plume with total dissolved solid (TDS) concentrations at times exceeding 100,000 mg/L was created in the subsurface. TDS concentrations in the plume were substantially greater than those in the CBNG water (about 2300 mg/L) and in the ambient shallow groundwater (about 8000 mg/L). Sulfate, sodium, and magnesium are the dominant ions in the plume. The elevated concentrations are attributed to cation-exchange-enhanced gypsum dissolution. As gypsum dissolves, calcium goes into solution and is exchanged for sodium and magnesium on clays. Removal of calcium from solution allows further gypsum dissolution.

  6. Pilot projects for the remediation of Sillamaee uranium tailings in Estonia

    International Nuclear Information System (INIS)

    Kaasik, T.; Siinmaa, A.

    2001-01-01

    First Estonian uranium, produced in a pilot plant at Narva, was presented to Soviet military administration in 1945 and just a year later - 1946 - installation of an uranium production plant was started at Sillamaee, Estonia. Estonian local ore - alum shale - containing only 0,026% of uranium was used for uranium production for nearly five years, after the plant was launched in 1948. The uranium mine, having been activated from 1947 to 1952, was left in status of 'active conservation' for 17 years, until finally closed in 1969. Potential threats of this hidden legacy have never been revealed. After close-down of local uranium mine, more than 4 million tons of ore, imported mostly from Central and East European countries: Czechoslovakia, Hungary and Eastern Germany were processed at Sillamaee. These activities have left a large tailings impoundment with the total volume of ca. 8 million cubic meters in the immediate vicinity of the Baltic Sea. Today the plant is privatized, converted to civil purposes and provides together its power generating facilities ca. 1200 jobs in the socially sensitive area of North-East Estonia, while environmental hazards of the history, however, remain: - Continuous seepage of tailing waters into the sea contributes and would contribute over long term to the pollution of the Baltic Sea; - stability of the tailings dam seaside under present conditions can not be guaranteed thus risking a sudden release of partly liquid tailings due to potential dam failure; - uncovered surface of the tailings presents a health hazard due to dusting and radon release and hinders the revitalization of the area. The conceptual design of the Estonia's largest environmental remediation project, done by Wismut, is now complete and first implementation steps are underway. The project for mine area restoration is in initiation phase; it shall reveal the current and potential environmental hazards of the facility and create the concept for necessary rehabilitation

  7. Microseismic Monitoring and 3D Finite Element Analysis of the Right Bank Slope, Dagangshan Hydropower Station, during Reservoir Impounding

    Science.gov (United States)

    Liu, Xingzong; Tang, Chun'an; Li, Lianchong; Lv, Pengfei; Liu, Hongyuan

    2017-07-01

    The right bank slope of Dagangshan hydropower station in China has complex geological conditions and is subjected to high in situ stress. Notably, microseismic activities in the right bank slope occurred during reservoir impounding. This paper describes the microseismic monitoring technology, and three-dimensional (3D) finite element analysis is used to explore the microseismic activities and damage mechanisms in the right bank slope during reservoir impounding. Based on data obtained from microseismic monitoring, a progressive microseismic damage model is proposed and implemented for 3D finite element analysis. The safety factor for the right bank slope after reservoir impoundment obtained from the 3D finite element analysis, which included the effects of progressive microseismic damage, was 1.10, indicating that the slope is stable. The microseismic monitoring system is able to capture the slope disturbance during reservoir impounding in real time and is a powerful tool for qualitatively assessing changes in slope stability over time. The proposed progressive microseismic damage model adequately simulates the changes in the slope during the impoundment process and provides a valuable tool for evaluating slope stability.

  8. Cumulative impoundment evaporation in water resource management within the mid-Atlantic: A case study in Virginia

    Science.gov (United States)

    Scott, D.; Burgholzer, R.; Kleiner, J.; Brogan, C. O.; Julson, C.; Withers, E.

    2017-12-01

    Across the eastern United States, successful management of water resources to satisfy the competing demands for human consumption, industry, agriculture, and ecosystems requires both water quality and water quantity considerations. Over the last 2 decades, low streamflows during dry summers have increased scrutiny on water supply withdrawals. Within Virginia, a statewide hydrologic model provides quantitative assessments on impacts from proposed water withdrawals to downstream river flow. Currently, evaporative losses are only accounted for from the large reservoirs. In this study, we sought to provide a baseline estimate for the cumulative evaporation from impoundments across all of the major river basins in Virginia. Virginia provides an ideal case study for the competing water demands in the mid-Atlantic region given the unique tracking of water withdrawals throughout the river corridor. In the over 73,000 Virginia impoundments, the cumulative annual impoundment evaporation was 706 MGD, or 49% of the permitted water withdrawal. The largest reservoirs (>100 acres) represented over 400 MGD, and 136 MGD for the smaller impoundments (planning will require not only understanding evaporation within large reservoirs, but also the thousands of small impoundments across the landscape.

  9. Cyanobacteria and cyanotoxins are present in drinking water impoundments and groundwater wells in desert environments.

    Science.gov (United States)

    Chatziefthimiou, Aspassia D; Metcalf, James S; Glover, W Broc; Banack, Sandra A; Dargham, Soha R; Richer, Renee A

    2016-05-01

    Desert environments and drylands experience a drastic scarcity of water resources. To alleviate dependence on freshwater for drinking water needs, countries have invested in infrastructure development of desalination plants. Collectively, the countries of the Arabian Gulf produce 45% of the world's desalinated water, which is stored in dams, mega-reservoirs and secondary house water tanks to secure drinking water beyond daily needs. Improper storage practices of drinking water in impoundments concomitant with increased temperatures and light penetration may promote the growth of cyanobacteria and accumulation of cyanotoxins. To shed light on this previously unexplored research area in desert environments, we examined drinking and irrigation water of urban and rural environments to determine whether cyanobacteria and cyanotoxins are present, and what are the storage and transportation practices as well as the environmental parameters that best predict their presence. Cyanobacteria were present in 80% of the urban and 33% of the rural water impoundments. Neurotoxins BMAA, DAB and anatoxin-a(S) were not detected in any of the water samples, although they have been found to accumulate in the desert soils, which suggests a bioaccumulation potential if they are leached into the aquifer. A toxic BMAA isomer, AEG, was found in 91.7% of rural but none of the urban water samples and correlated with water-truck transportation, light exposure and chloride ions. The hepatotoxic cyanotoxin microcystin-LR was present in the majority of all sampled impoundments, surpassing the WHO provisional guideline of 1 μg/l in 30% of the urban water tanks. Finally, we discuss possible management strategies to improve storage and transportation practices in order to minimize exposure to cyanobacteria and cyanotoxins, and actions to promote sustainable use of limited water resources. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Relationships among catch, angler catisfaction, and fish assemblage characteristics of an urban small impoundment fishery

    Science.gov (United States)

    Ivasauskas, Tomas J.; Xiong, Wilson N.; Engman, Augustin C.; Fischer, Jesse R.; Kwak, Thomas J.; Rundle, Kirk R.

    2017-01-01

    Urban fisheries provide unique angling opportunities for people from traditionally underrepresented demographics. Lake Raleigh is a 38-ha impoundment located on the North Carolina State University campus in Raleigh. Like many urban fisheries, little is known about angler use and satisfaction or how angling catch rate is related to fish availability in Lake Raleigh. We characterized the recreational fishery and fish assemblage with concurrent creel and boat electrofishing surveys over the course of one year. In total, 245 anglers were interviewed on 68 survey days. On average, anglers spent 1.7 h fishing per trip and caught 0.385 fish h –1. A large proportion of anglers (43.9%) targeted multiple species, whereas 36.5% targeted largemouth bass (Micropterus salmoides), 10.0% targeted panfish (i.e., sunfishes [Lepomis spp.] and crappies [Pomoxis spp.]), and 9.6% targeted catfish (Ameiurus spp. and Ictalurus spp.). Most anglers (69.4%) were satisfied with their experience, and overall satisfaction was unrelated to catch rate. Pulsed-DC boat electrofishing was conducted on 25 dates, and 617 fish were sampled. Angler catch rate was unrelated to electrofishing catch rate, implying that anglers' catch rate was independent of fish density or availability. Our results demonstrate that even minimally managed urban fisheries can provide high angler satisfaction, with limited dedication of management resources. Relationships Among Catch, Angler Satisfaction, and Fish Assemblage Characteristics of an Urban Small Impoundment Fishery (PDF Download Available). Available from: https://www.researchgate.net/publication/316636550_Relationships_Among_Catch_Angler_Satisfaction_and_Fish_Assemblage_Characteristics_of_an_Urban_Small_Impoundment_Fishery [accessed Aug 11, 2017].

  11. 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.

  12. The 27 May 1937 catastrophic flow failure of gold tailings at Tlalpujahua, Michoacan, Mexico

    Science.gov (United States)

    Macias, J. L.; Corona-Chavez, P.; Sanchez-Nunez, J. M.; Martinez-Medina, M.; Garduno-Monroy, V. H.; Capra, L.; Garcia-Tenorio, F.; Cisneros-Maximo, G.

    2015-05-01

    On 27 May 1937, after one week of sustained heavy rainfall, a voluminous flood caused the death of at least 300 people and the destruction of the historic El Carmen church and several neighborhoods in the mining region of Tlalpujahua, Michoacan, central Mexico. This destructive flood was triggered by the breaching of the impoundment of the Los Cedros tailings and the sudden release of circa 16 Mt of water-saturated waste materials. The muddy silty flood, moving at estimated speeds of 20-25 m s-1, was channelized along the Dos Estrellas and Tlalpujahua drainages and devastated everything along its flow path. After advancing 2.5 km downstream, the flood slammed into El Carmen church and surrounding houses at estimated speeds of ~ 7 m s-1, destroying many construction walls and covering the church floor with ~ 2 m of mud and debris. Revision of eyewitness accounts and newspaper articles, together with analysis of archived photographic materials, indicated that the flood consisted of three muddy pulses. Stratigraphic relations and granulometric data for selected proximal and distal samples show that the flood behaved as a hyperconcentrated flow along most of its trajectory. A total volume of the Lamas flood deposit was estimated as 1.5 x 106 m3. The physically based bidimensional (2-D) hydraulic model FLO-2D was implemented to reproduce the breached flow (0.5 sediment concentration) with a maximum flow discharge of 8000 m3 s-1 for a total outflow volume (sediment + water) of 2.5 x 106 m3, similar to the calculations obtained using field measurements. Even though premonitory signs of possible impoundment failure were reported days before the flood, and people living downstream were alerted, authorities ordered no evacuations or other mitigative actions. The catastrophic flood at Tlalpujahua provides a well-documented, though tragic, example of impoundment breaching of a tailings dam caused by the combined effects of intense rainfall, dam weakness, and inadequate

  13. Geochemical behavior and environmental risks related to the use of abandoned base-metal tailings as construction material in the upper-Moulouya district, Morocco.

    Science.gov (United States)

    Argane, R; El Adnani, M; Benzaazoua, M; Bouzahzah, H; Khalil, A; Hakkou, R; Taha, Y

    2016-01-01

    In some developing countries, base-metal residues that were abandoned in tailing ponds or impoundments are increasingly used as construction material without any control, engineering basis, or environmental concern. This uncontrolled reuse of mine tailings may constitute a new form of pollution risks for humans and ecosystems through metal leaching. Therefore, the aim of the current study is to assess mine drainage, metal mobility, and geochemical behavior of two abandoned mine tailings commonly used in the upper-Moulouya region (eastern Morocco) as fine aggregates for mortar preparation. Their detailed physical, chemical, and mineralogical properties were subsequently evaluated in the context of developing appropriate alternative reuses to replace their conventional disposal and limit their weathering exposure. The obtained results showed that both tailings contain relatively high quantities of residual metals and metalloids with lead (ranging between 3610 and 5940 mg/kg) being the major pollutant. However, the mineralogical investigations revealed the presence of abundant neutralizing minerals and low sulfide content which influence mine drainage geochemistry and subsequently lower metals mobility. In fact, leachate analyses from weathering cell kinetic tests showed neutral conditions and low sulfide oxidation rates. According to these results, the tailings used as construction material in the upper-Moulouya region have very low generating potential of contaminated effluents and their reuse as aggregates may constitute a sustainable alternative method for efficient tailing management.

  14. The tail of integrin activation

    Science.gov (United States)

    Anthis, Nicholas J; Campbell, Iain D

    2010-01-01

    Integrins are essential adhesion receptors found on the surfaces of all metazoan cells. As regulators of cell migration and extracellular matrix assembly, these membrane-spanning heterodimers are critical for embryonic development, tissue repair and immune responses. Signals transmitted by integrins from outside to inside the cell promote cell survival and proliferation, but integrin affinity for extracellular ligands can also be controlled by intracellular cues. This bidirectional signaling is mediated by the short cytoplasmic tails of the two integrin subunits. Recent structural and functional studies of various integrin fragments and complexes between the cytoplasmic tails and intracellular proteins, such as talin, have provided new insight into the signaling processes centered around the tails, particularly inside-out integrin activation. PMID:21216149

  15. Impoundment of the Zipingpu reservoir and triggering of the 2008 Mw 7.9 Wenchuan earthquake, China.

    Science.gov (United States)

    Tao, Wei; Masterlark, Timothy; Shen, Zheng-Kang; Ronchin, Erika

    2015-10-01

    Impoundment of the Zipingpu reservoir (ZR), China, began in September 2005 and was followed 2.7 years later by the 2008 M w 7.9 Wenchuan earthquake (WE) rupturing the Longmen Shan Fault (LSF), with its epicenter ~12 km away from the ZR. Based on the poroelastic theory, we employ three-dimensional finite element models to simulate the evolution of stress and pore pressure due to reservoir impoundment, and its effect on the Coulomb failure stress on the LSF. The results indicate that the reservoir impoundment formed a pore pressure front that slowly propagated through the crust with fluid diffusion. The reservoir loading induced either moderate or no increase of the Coulomb failure stress at the hypocenter prior to the WE. The Coulomb failure stress, however, grew ~9.3-69.1 kPa in the depth range of 1-8 km on the LSF, which may have advanced tectonic loading of the fault system by ~60-450 years. Due to uncertainties of fault geometry and hypocenter location of the WE, it is inconclusive whether impoundment of the ZR directly triggered the WE. However, a small event at the hypocenter could have triggered large rupture elsewhere on fault, where the asperities were weakened by the ZR. The microseismicity around the ZR also showed an expanding pattern from the ZR since its impoundment, likely associated with diffusion of a positive pore pressure pulse. These results suggest a poroelastic triggering effect (even if indirectly) of the WE due to the impoundment of the ZR.

  16. An Object-Based Machine Learning Classification Procedure for Mapping Impoundments in Brazil's Amazon-Cerrado Agricultural Frontier

    Science.gov (United States)

    Solvik, K.; Macedo, M.; Graesser, J.; Lathuilliere, M. J.

    2017-12-01

    Large-scale agriculture and cattle ranching in Brazil has driving the creation of tens of thousands of small stream impoundments to provide water for crops and livestock. These impoundments are a source of methane emissions and have significant impacts on stream temperature, connectivity, and water use over a large region. Due to their large numbers and small size, they are difficult to map using conventional methods. Here, we present a two-stage object-based supervised classification methodology for identifying man-made impoundments in Brazil. First, in Google Earth Engine pixels are classified as water or non-water using satellite data and HydroSHEDS products as predictors. Second, using Python's scikit-learn and scikit-image modules the water objects are classified as man-made or natural based on a variety of shape and spectral properties. Both classifications are performed by a random forest classifier. Training data is acquired by visually identifying impoundments and natural water bodies using high resolution satellite imagery from Google Earth.This methodology was applied to the state of Mato Grosso using a cloud-free mosaic of Sentinel 1 (10m resolution) radar and Sentinel 2 (10-20m) multispectral data acquired during the 2016 dry season. Independent test accuracy was estimated at 95% for the first stage and 93% for the second. We identified 54,294 man-made impoundments in Mato Grosso in 2016. The methodology is generalizable to other high resolution satellite data and has been tested on Landsat 5 and 8 imagery. Applying the same approach to Landsat 8 images (30 m), we identified 35,707 impoundments in the 2015 dry season. The difference in number is likely because the coarser-scale imagery fails to detect small (< 900 m2) objects. On-going work will apply this approach to satellite time series for the entire Amazon-Cerrado frontier, allowing us to track changes in the number, size, and distribution of man-made impoundments. Automated impoundment mapping

  17. Horse impoundments under Control of Horses legislation in the Munster region of Ireland: factors affecting euthanasia.

    Science.gov (United States)

    Cullinane, M; O'Sullivan, E; Collins, D M; Byrne, A W; More, S J

    2015-01-24

    Recently, considerable international attention has been paid to the problem of unwanted horses. In Ireland, stray horses, particularly in urban areas, are a further problem. The Control of Horses Act 1996 was enacted in response to an ongoing problem of uncontrolled horses in public places. As yet, no research work has been conducted focusing on stray horses in Ireland. This paper describes horses impounded under the Act in the Munster region of Ireland during 2005-2012 and the factors influencing decisions regarding their disposal. A logistic regression model was developed to investigate factors influencing the probability that a horse was euthanised during impoundment. In total, 3625 seizure events were recorded, most towards the end of the study period. Predictors for euthanasia during 2010-2012 included seizure location, sex, age, colour, body condition score and year. This study highlights the problem of stray horses in Ireland, particularly in urban areas. There is a need for rigorous enforcement of newly enacted horse identification legislation, allowing a fully integrated traceability system. More is required to manage the long-established societal problems of stray horses in urban settings, with a uniform approach by all Local Authorities being long overdue. British Veterinary Association.

  18. Transport and dispersion of pollutants in surface impoundments: a finite element model

    International Nuclear Information System (INIS)

    Yeh, G.T.

    1980-07-01

    A surface impoundment model in finite element (SIMFE) is presented to enable the simulation of flow circulations and pollutant transport and dispersion in natural or artificial lakes, reservoirs or ponds with any number of islands. This surface impoundment model consists of two sub-models: hydrodynamic and pollutant transport models. Both submodels are simulated by the finite element method. While the hydrodynamic model is solved by the standard Galerkin finite element scheme, the pollutant transport model can be solved by any of the twelve optional finite element schemes built in the program. Theoretical approximations and the numerical algorithm of SIMFE are described. Detail instruction of the application are given and listing of FORTRAN IV source program are provided. Two sample problems are given. One is for an idealized system with a known solution to show the accuracy and partial validation of the models. The other is applied to Prairie Island for a set of hypothetical input data, typifying a class of problems to which SIMFE may be applied

  19. Transport and dispersion of pollutants in surface impoundments: a finite element model

    Energy Technology Data Exchange (ETDEWEB)

    Yeh, G.T.

    1980-07-01

    A surface impoundment model in finite element (SIMFE) is presented to enable the simulation of flow circulations and pollutant transport and dispersion in natural or artificial lakes, reservoirs or ponds with any number of islands. This surface impoundment model consists of two sub-models: hydrodynamic and pollutant transport models. Both submodels are simulated by the finite element method. While the hydrodynamic model is solved by the standard Galerkin finite element scheme, the pollutant transport model can be solved by any of the twelve optional finite element schemes built in the program. Theoretical approximations and the numerical algorithm of SIMFE are described. Detail instruction of the application are given and listing of FORTRAN IV source program are provided. Two sample problems are given. One is for an idealized system with a known solution to show the accuracy and partial validation of the models. The other is applied to Prairie Island for a set of hypothetical input data, typifying a class of problems to which SIMFE may be applied.

  20. Microcrustaceans (Branchipoda and Copepoda) of Wetland Impoundments on the Savannah River Site, Aiken, South Carolina

    Energy Technology Data Exchange (ETDEWEB)

    DeBiase, Adrienne E; Taylor, Barbara E

    2005-09-21

    The United States Department of Energy’s Savannah River Site (SRS) in Aiken, Allendale, and Barnwell Counties, South Carolina, contains an abundance of freshwater wetlands and impoundments. Four large impoundments, as well as several small, abandoned farm and mill ponds, and about 400 Carolina bays and other small, isolated depression wetland ponds are located within the 893 km2 area of the SRS. Crustaceans of the orders Branchiopoda and Copepoda are nearly ubiquitous in these water bodies. Although small in size, these organisms are often very abundant. They consequently play an important trophic role in freshwater food webs supporting fish, larval salamanders, larval insects, and numerous other animals, aquatic and terrestrial. This report provides an introduction to the free-living microcrustaceans of lentic water bodies on the SRS and a comprehensive list of species known to occur there. Occurrence patterns are summarized from three extensive survey studies, supplemented with other published and unpublished records. In lieu of a key, we provide a guide to taxonomic resources and notes on undescribed species. Taxa covered include the orders Cladocera, Anostraca, Laevicaudata, and Spinicaudata of the Subclass Branchiopoda and the Superorders Calanoida and Cyclopoida of Subclass Copepoda. Microcrustaceans of the Superorder Harpacticoida of the Subclass Copepoda and Subclass Ostracoda are also often present in lentic water bodies. They are excluded from this report because they have not received much study at the species level on the SRS.

  1. Post-remediation action radiological report for Surface Impoundments C (3539) and D (3540) at the Oak Ridge National Laboratory, Oak Ridge, Tennessee

    International Nuclear Information System (INIS)

    1998-12-01

    During August and September 1998, Bechtel Jacobs Company LLC performed a remedial action within Impoundments 3539 and 3540 (Impoundments C and D, respectively) in accordance with the Comprehensive Environmental Response, Compensation, and Liability Act Record of Decision (ROD) for the Surface Impoundments Operable Unit. The remedial action included removal of sediments and 0.1 ft of subimpoundment soil. A post-remedial action radiological survey was conducted to provide data to support the Bethel Valley ROD. Data was obtained from (1) a walkover survey for residual gamma radiation on the base of the impoundments, (2) smear surveys for transferable contamination on remaining riprap, and (3) representative sampling of subimpoundment soils. Walkover surveys identified no locations outside the impoundments with gamma exposure levels greater than three times background levels. Smear surveys detected no removable contamination above release limits as specified in 10 CFR 835, Appendix D. Subimpoundment soil samples quantified low levels of residual contamination

  2. Post-remediation action radiological report for Surface Impoundments C (3539) and D (3540) at the Oak Ridge National Laboratory, Oak Ridge, Tennessee

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-12-01

    During August and September 1998, Bechtel Jacobs Company LLC performed a remedial action within Impoundments 3539 and 3540 (Impoundments C and D, respectively) in accordance with the Comprehensive Environmental Response, Compensation, and Liability Act Record of Decision (ROD) for the Surface Impoundments Operable Unit. The remedial action included removal of sediments and 0.1 ft of subimpoundment soil. A post-remedial action radiological survey was conducted to provide data to support the Bethel Valley ROD. Data was obtained from (1) a walkover survey for residual gamma radiation on the base of the impoundments, (2) smear surveys for transferable contamination on remaining riprap, and (3) representative sampling of subimpoundment soils. Walkover surveys identified no locations outside the impoundments with gamma exposure levels greater than three times background levels. Smear surveys detected no removable contamination above release limits as specified in 10 CFR 835, Appendix D. Subimpoundment soil samples quantified low levels of residual contamination.

  3. 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 examin......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...

  4. 40 CFR 63.7905 - What emissions limitations or work practice standards must I meet for surface impoundments?

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 13 2010-07-01 2010-07-01 false What emissions limitations or work practice standards must I meet for surface impoundments? 63.7905 Section 63.7905 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE...

  5. Interrelationships between fish tissue mercury concentrations and water quality for South Dakota natural lakes and impoundments

    Science.gov (United States)

    Chipps, Steven R.; Stetler, Larry; Stone, James J.; McCutcheon, Cindy M.

    2011-01-01

    The purpose of this study was to determine whether water quality parameters commonly associated with primary productivity may be used to predict the susceptibility of a specific water body to exceed proposed fish consumption advisory limitation of 0.3 mg kg−1. South Dakota currently has nine lakes and impoundments that exceed fish tissue mercury advisory limits of 1.0 mg kg−1 total mercury, far exceeding US Environmental Protection Agency and Food and Drug Administration 0.3 mg kg−1 consumption criteria. Previous studies suggest that increased aquatic productivity may mitigate the effects of biological production and subsequent uptake of methyl mercury through bio-dilution; however, it is uncertain whether these trends may exist within highly alkaline and highly productive aquatic conditions common to South Dakota lakes and impoundments. Water quality parameters and fish tissue mercury data for northern pike and walleye were collected and assessed using existing South Dakota Department of Environment and Natural Resources and Game Fish and Parks data. The data was initially screened using both parametric linear regression and non-parametric Mann–Whitney rank sum comparisons and further assessed using binary logistic regression and stepwise logistic regression methodology. Three separate phosphorus measurements (total, total dissolved, and Trophic State Index) and pH were determined to significantly correlate with increased mercury concentrations for the northern pike-in-impoundments model. However, phosphorus surprisingly was not a strong predictor for the remaining scenarios modeled. For the northern pike-in-natural lakes models, alkalinity was the most significant water quality parameter predicting increased mercury concentrations. Mercury concentrations for the walleye-in-natural lakes models were further influenced by pH and alkalinity. The water quality and fish tissue mercury interrelationships determined within this study suggest aquatic

  6. Reestablishing the Dominance of Biogeochemical Pathways for Reducing Downstream Nutrient Losses from Aged Impounded Features

    Science.gov (United States)

    Shukla, S.; Shukla, A.

    2017-12-01

    Water and phosphorus (P) dynamics and loss pathways at two stormwater impoundments (SIs) were analyzed using measured fluxes between 2008 and 2011. These SIs are a decade old. Analyses of water and P budgets along with the discernment of various P pools and characterization of the intermediary processes revealed that soil adsorption and plant uptake are secondary to volume reduction apropos of P treatment. At one site, extreme wet conditions in a year combined with soil P saturation resulted in it being a P source rather than a sink. The impoundment (SI-1) discharged 12% more P than incoming due to soil P desorption, a consequence of dilution of incoming stormwater with large water input from an extreme tropical rain event. The second impoundment (SI-2) was a consistent sink of P; 55% and 95% of the incoming total P was retained in the two years, mainly as a result of 49% and 84% volume retention, respectively. Analysis of plant available aluminum, iron, and phosphorus showed the surface soil to be P saturated and at risk of releasing P to a limit of environmental concern. These results when seen in light of more frequent extreme precipitation events under the changed climate scenario call for alternatives to revive the role of biogeochemical processes in P treatment because volume reduction may not always be the viable option, especially for wet conditions. Aboveground biomass harvesting and removal was evaluated to transform the SIs from a frequent P source to sink and maintain the long-term sink functions of the SIs. Use of harvested biomass as a source of nutrients (N and P) and carbon to agricultural soil can result in beneficial use of biomass and offset the cost of harvesting. Other avenues such as altering the hydrology of the SIs by compartmentalizing the system and increasing the storage were also explored for short-term benefits. Results provided a combination of hydraulic and biochemical options for achieving long-term water and nutrient retentions in

  7. Uranium-mill-tailings conditioning technology

    International Nuclear Information System (INIS)

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

    1982-01-01

    Conditioning of uranium mill tailings involves the physico-chemical 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 sntering tailings at high temperatures (1100 to 1200 0 C) to radically alter the structure of tailings. This thermal stabilization at 1200 0 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. 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. Sulfuric 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 stag extraction. An economic analysis of a sulfuric 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 leaching step and would contribute about 60% of the costs of moving and burying the tailings at a new site

  8. [Comparison of trophic status analysis of the Daning River within the Three Gorges Reservoir before and after experimental impoundment].

    Science.gov (United States)

    Zhang, Jia-Lei; Zheng, Bing-Hui; Liu, Lu-San; Wang, Li-Jing; Wu, Guang-Ying

    2012-10-01

    We evaluated 4-year data set to assess the trophic state and limiting factors of the Three Gorges Reservoir (TGR) during the experimental impounding period (September 2005 to September 2007) and the normal operating period (September 2008 to September 2010). The results indicated that there had been appeared new characteristics in spatial and temporal distribution of trophic state indices after impoundment. The trophic state indices (TSI(TP)) showed increased trend after the TGR impoundment during the study area, but TSI(TN) and TSI(SD) had no significant changes after the TGR impoundment. The values of TSI(CHL) showed increased trend after the TGR impoundment in S1, and the values of TSI(CHL) did not show obvious changes in S2, S3 and S4 after the TGR impoundment. The values of TSI(TN), TSI(TP) and TSI(SD) show similar spatial variances with the highest value in S4, followed in a descending order by S3, S2 and S1. TSI(CHL) in the S2 and S3 were higher than that in S1 and S4. According to the characteristics of water level, the operational period of the TGR classified into following four stages: stage I (pre-November-April), stage II (May-July), stage III (July-September) and stage IV (September-November). The values of TSI(TN) and TSI(TP) in the Daning River and the TGR mainstream showed similar seasonal variances with the highest value in the stage II and III, followed in a descending order by stage I and IV. The values of TSI(CHL) varied substantially among the four stages, with the highest value in stage III, followed by stage II, IV and I. The trophic state indices differences were getting smaller between the four stages after the TGR impoundment. Using Carlson's two-dimensional approach, deviations of the TSI(S) indicated that factors other than phosphorous and nitrogen limited algal growth and that nonalgal particles affected light attenuation. These findings were further supported by the significant correlation among the values of TSI and hydrological

  9. 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.

  10. Geomorphological and botanical change on the Outer Slave River Delta, NWT, before and after impoundment of the Peace River

    Science.gov (United States)

    English, Michael C.; Hill, R. Brad; Stone, Micheal A.; Ormson, Ron

    1997-10-01

    This paper examines geomorphological and botanical changes on the outer low elevation portion of the Slave River Delta prior to and after impoundment of the Peace River at Hudson's Hope, British Columbia. The Slave River Delta deposits are approximately 8300 km2, about 5% (400 km2) is defined as the active delta which progrades into Great Slave Lake through an active system of distributaries. This active portion of the delta is the area studied.The Peace River provides approximately 65% of the annual flow of the Slave River. Alteration of the natural flow regime and suspended sediment load of the Slave River has resulted from the upstream impoundment. Calculations indicate that the annual suspended sediment load in the Slave River has decreased by 33%. Using aerial photographs of the Slave Delta taken in 1946 and 1966, prior to damming the Peace River, geomorphological change and the spatial changes in plant assemblages have been recorded using GIS software. Aerial photographs taken in 1977 and 1994 were used in similar fashion to document geomorphological and botanical change and rates of change after impoundment. The Outer Delta is most susceptible to hydrological and suspended sediment changes in the river system. As such it is shown that geomorphological development in these Outer Delta landforms has been notably reduced since impoundment and changes in plant assemblage distribution indicate a drier, less productive environment. Results of aerial photo analysis show that the rate of development of distinctive cleavage bar islands on the Outer Delta has been notably reduced since impoundment. Changes in plant assemblage areas on these islands indicates both an autogenic and allogenic change to a drier, less productive environment and actual loss, by erosion, of some of the most productive Equisetum assemblages.

  11. Chlorophyll Detection and Mapping of Shallow Water Impoundments Using Image Spectrometry

    International Nuclear Information System (INIS)

    Artigas, F.; Pechmann, I.; Marti, A.; Yao, N.; Pechmann, I.

    2008-01-01

    There exists a common perception that chlorophyll a concentrations in tidal coastal waters are unsuitable to be captured by remote sensing techniques because of high water turbidity. In this study, we use band index measurements to separate active chlorophyll pigments from other constituents in the water. Published single- and multiband spectral indices are used to establish a relationship between algal chlorophyll concentration and reflectance data. We find an index which is suitable to map chlorophyll gradients in the impoundments, ditches, and associated waterways of the Hackensack Meadow lands (NJ, USA). The resulting images clearly depict the spatial distribution of plant pigments and their relationship with the biological conditions of the waters in the estuary. Since these biological conditions are often determined by land usage, the methods in this paper provide a simple tool to address water quality management issues in fragmented urban estuaries.

  12. Long-term changes in fish assemblage following the impoundments of the Three Gorges Reservoir in Hejiang, a protected reach of the upper Yangtze River

    Directory of Open Access Journals (Sweden)

    Liu F.

    2013-03-01

    Full Text Available The construction of the Three Gorges Reservoir (TGR has seriously affected the fish assemblage in the impounded reaches. However, fish assemblage changes in the riverine zone remain poorly documented. In order to explore how upstream fish assemblage has responded to the successive impoundments of the TGR, fish investigations were conducted biannually in Hejiang, a protected reach of the upper Yangtze River, during the period from 1997 to 2011. Multivariate analysis revealed significant temporal differences in fish assemblage following the impoundments of the TGR. Prior to the impoundments, the fish assemblage appeared to be very diversified and very even. Immediately after the first and the second impoundment, the lotic species, such as Coreius guichenoti, Rhinogobio ventralis, Rhinogobio cylindricus and Coreius heterodon, became evidently dominant, due to their upstream migrations from the reservoir. However, two years after the third impoundment, the lotic species decreased dramatically, while lentic Hypophthalmichthys molitrix and Pelteobagrus vachelli became the new dominant species. Based on this and other studies, we can see the habitats of the riverine fish in the upper Yangtze River have been shrunk seriously because of the impoundments of the TGR. The cascade hydropower development in the lower Jinsha River will pose an accumulative effect on the aquatic environment in the mainstream of the upper Yangtze River. Free-flowing tributaries, such as the Chishui River, will play more important roles in fish conservation.

  13. Fishers' knowledge identifies environmental changes and fish abundance trends in impounded tropical rivers.

    Science.gov (United States)

    Hallwass, Gustavo; Lopes, Priscila F; Juras, Anastácio A; Silvano, Renato A M

    2013-03-01

    The long-term impacts of large hydroelectric dams on small-scale fisheries in tropical rivers are poorly known. A promising way to investigate such impacts is to compare and integrate the local ecological knowledge (LEK) of resource users with biological data for the same region. We analyzed the accuracy of fishers' LEK to investigate fisheries dynamics and environmental changes in the Lower Tocantins River (Brazilian Amazon) downstream from a large dam. We estimated fishers' LEK through interviews with 300 fishers in nine villages and collected data on 601 fish landings in five of these villages, 22 years after the dam's establishment (2006-2008). We compared these two databases with each other and with data on fish landings from before the dam's establishment (1981) gathered from the literature. The data obtained based on the fishers' LEK (interviews) and from fisheries agreed regarding the primary fish species caught, the most commonly used type of fishing gear (gill nets) and even the most often used gill net mesh sizes but disagreed regarding seasonal fish abundance. According to the interviewed fishers, the primary environmental changes that occurred after the impoundment were an overall decrease in fish abundance, an increase in the abundance of some fish species and, possibly, the local extinction of a commercial fish species (Semaprochilodus brama). These changes were corroborated by comparing fish landings sampled before and 22 years after the impoundment, which indicated changes in the composition of fish landings and a decrease in the total annual fish production. Our results reinforce the hypothesis that large dams may adversely affect small-scale fisheries downstream and establish a feasible approach for applying fishers' LEK to fisheries management, especially in regions with a low research capacity.

  14. 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...... experiment at 40 mA, with approximately 137.5 g mine tailings on dry basis. The removal for a static (baseline) experiment only amounted 15% when passing approximately the same amount of charge through 130 g of mine tailings. The use of air bubbling to keep the tailings suspended increased the removal...

  15. Jarosite versus Soluble Iron-Sulfate Formation and Their Role in Acid Mine Drainage Formation at the Pan de Azúcar Mine Tailings (Zn-Pb-Ag, NW Argentina

    Directory of Open Access Journals (Sweden)

    Jesica Murray

    2014-05-01

    Full Text Available Secondary jarosite and water-soluble iron-sulfate minerals control the composition of acid mine waters formed by the oxidation of sulfide in tailings impoundments at the (Zn-Pb-Ag Pan de Azúcar mine located in the Pozuelos Lagoon Basin (semi-arid climate in Northwest (NW Argentina. In the primary zone of the tailings (9.5 wt % pyrite-marcasite precipitation of anglesite (PbSO4, wupatkite ((Co,Mg,NiAl2(SO44 and gypsum retain Pb, Co and Ca, while mainly Fe2+, Zn2+, Al3+, Mg2+, As3+/5+ and Cd2+ migrate downwards, forming a sulfate and metal-rich plume. In the oxidation zone, jarosite (MFe3(TO42(OH6 is the main secondary Fe3+ phase; its most suitable composition is M = K+, Na+, and Pb2+and TO4 = SO42−; AsO42−. During the dry season, iron-sulfate salts precipitate by capillary transport on the tailings and at the foot of DC2 (tailings impoundment DC2 tailings dam where an acid, Fe2+ rich plume outcrops. The most abundant compounds in the acid mine drainage (AMD are SO42−, Fe2+, Fe3+, Zn2+, Al3+, Mg2+, Cu2+, As3+/5+, Cd2+. These show peak concentrations at the beginning of the wet season, when the soluble salts and jarosite dissolve. The formation of soluble sulfate salts during the dry season and dilution during the wet season conform an annual cycle of rapid metals and acidity transference from the tailings to the downstream environment.

  16. Pollution of ground water due to inactive uranium mill tailings. Summary of progress, October 1, 1979-September 30, 1981

    Energy Technology Data Exchange (ETDEWEB)

    1980-01-01

    An extensive program of characterization of several inactive uranium tailings piles has been carried out in the past year. The geotechnical engineering program conducted a drilling program at the Salt Lake City and Grand Junction sites. The locations of slimes and sands in these sites hve been characterized. In general, it was found that slimes exist in the impoundments in lower percentages than normally produced from mill tailings. Permeability tests were conducted yielding values ranging from 10/sup -3/ cm/sec to 10/sup -6/cm/sec. The geochemical studies made considerable progress in the past year. Extensive sampling of several sites was conducted. Sampling programs have been completed for seven sites and are underway for nine other sites. The work to date has indicated the importance of salts in controlling the direction and rate of movement of contaminants. The work has also indicated that a number of non-radioactive elements such as As are of environmental importance. The work also indicates the importance of the fact that the tailings piles are out of chemical equilibrium with their environment. Computer software was developed and implemented for data storage and retrieval. Automation hardware was installed and tested for the Inductively Coupled Plasma Emission Spectrometer. A number of analytical protocols were developed for routine analyses. A comprehensive quality control program was implemented. More than 18,000 chemical analyses were performed.

  17. Pollution of ground water due to inactive uranium mill tailings. Summary of progress, October 1, 1979-September 30, 1981

    International Nuclear Information System (INIS)

    1980-01-01

    An extensive program of characterization of several inactive uranium tailings piles has been carried out in the past year. The geotechnical engineering program conducted a drilling program at the Salt Lake City and Grand Junction sites. The locations of slimes and sands in these sites hve been characterized. In general, it was found that slimes exist in the impoundments in lower percentages than normally produced from mill tailings. Permeability tests were conducted yielding values ranging from 10 -3 cm/sec to 10 -6 cm/sec. The geochemical studies made considerable progress in the past year. Extensive sampling of several sites was conducted. Sampling programs have been completed for seven sites and are underway for nine other sites. The work to date has indicated the importance of salts in controlling the direction and rate of movement of contaminants. The work has also indicated that a number of non-radioactive elements such as As are of environmental importance. The work also indicates the importance of the fact that the tailings piles are out of chemical equilibrium with their environment. Computer software was developed and implemented for data storage and retrieval. Automation hardware was installed and tested for the Inductively Coupled Plasma Emission Spectrometer. A number of analytical protocols were developed for routine analyses. A comprehensive quality control program was implemented. More than 18,000 chemical analyses were performed

  18. 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

  19. Responsiveness summary for the engineering evaluation/cost analysis for the proposed management of contaminated water impounded at the Weldon Spring Chemical Plant Area

    International Nuclear Information System (INIS)

    Maxey, M.L.; MacDonell, M.M.; Peterson, J.M.

    1991-01-01

    The US Department of Energy (DOE) issued the Engineering Evaluation/Cost Analysis for the Proposed Management of Contaminated Water Impounded at the Weldon Spring Chemical Plant Area in July 1990. The engineering evaluation/cost analysis (EE/CA) examines various alternatives for the proposed action to manage contaminated surface water impounded at the chemical plant area. The primary objective is to minimize potential migration of contaminants from surface impoundments to the local environment. The EE/CA addresses water currently impounded in four waste raffinate pits and two small ponds and water that will be impounded in the future as a result of upcoming response actions. Radioactive and chemical contaminants are migrating from the currently impounded water to underlying on-site groundwater via seepage and to off-site surface water via runoff. The treatment process and facilities that will be provided for management of currently impounded water can subsequently be used to manage other contaminated water in the future. Based on the evaluation of various alternatives in the EE/CA, DOE determined that the best approach for managing surface water impounded at the chemical plant area would be to remove contaminants from the water and release the treatment water to the Missouri River via a natural drainage channel. To establish requirements for releasing this treated water, DOE applied for a modification to its existing discharge permit from the Missouri Department of Natural Resources (DNR) under the National Pollutant Discharge Elimination System (NPDES) program. The EE/CA provided a major source of technical input to the application for modifying the permit. This responsiveness summary has been prepared to address the major issues identified in oral and written comments on the proposed action. 1 tab

  20. Assessment of sediments in the riverine impoundments of national wildlife refuges in the Souris River Basin, North Dakota

    Science.gov (United States)

    Tangen, Brian A.; Laubhan, Murray K.; Gleason, Robert A.

    2014-01-01

    Accelerated sedimentation of reservoirs and riverine impoundments is a major concern throughout the United States. Sediments not only fill impoundments and reduce their effective life span, but they can reduce water quality by increasing turbidity and introducing harmful chemical constituents such as heavy metals, toxic elements, and nutrients. U.S. Fish and Wildlife Service national wildlife refuges in the north-central part of the United States have documented high amounts of sediment accretion in some wetlands that could negatively affect important aquatic habitats for migratory birds and other wetland-dependent wildlife. Therefore, information pertaining to sediment accumulation in refuge impoundments potentially is important to guide conservation planning, including future management actions of individual impoundments. Lands comprising Des Lacs, Upper Souris, and J. Clark Salyer National Wildlife Refuges, collectively known as the Souris River Basin refuges, encompass reaches of the Des Lacs and Souris Rivers of northwestern North Dakota. The riverine impoundments of the Souris River Basin refuges are vulnerable to sedimentation because of the construction of in-stream dams that interrupt and slow river flows and because of post-European settlement land-use changes that have increased the potential for soil erosion and transport to rivers. Information regarding sediments does not exist for these refuges, and U.S. Fish and Wildlife Service personnel have expressed interest in assessing refuge impoundments to support refuge management decisions. Sediment cores and surface sediment samples were collected from impoundments within Des Lacs, Upper Souris, and J. Clark Salyer National Wildlife Refuges during 2004–05. Cores were used to estimate sediment accretion rates using radioisotope (cesium-137 [137Cs], lead-210 [210Pb]) dating techniques. Sediment cores and surface samples were analyzed for a suite of elements and agrichemicals, respectively. Examination of

  1. Engineering evaluation/cost analysis for the proposed management of contaminated water impounded at the Weldon Spring chemical plant area

    International Nuclear Information System (INIS)

    MacDonell, M.M.; Maxey, M.L.; Peterson, J.M.; Joya, I.E.

    1990-07-01

    This engineering evaluation/cost analysis (EE/CA) report has been prepared to support the proposed removal action for managing contaminated surface waters impounded at the chemical plant area of the Weldon Spring site, located near Weldon Spring, Missouri. The US Department of Energy is responsible for cleanup activities at the site under its Surplus Facilities Management Program (SFMP). The major goals of SFMP are to eliminate potential hazards to human health and the environment that are associated with contamination at SFMP sites and to make surplus real property available for other uses, to the extent possible. The objectives of this EE/CA report are to identify the cleanup as a removal action, document the selection of a response that will mitigate the potential release of radioactive or chemical contaminants from the impounded waters into the nearby environment, and address environmental impacts associated with the proposed action. 41 refs., 8 figs., 8 tabs

  2. 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...... by scoring the tail of each individual pig. A pen was recorded as a tail damage pen and no longer included in the study if at least one pig in a pen had a bleeding tail wound; thus, only the first incidence of tail damage on pen level was recorded. Data were analysed by a Cox regression for survival analysis...

  3. 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.

  4. Evaluation of behaviors of earth and rockfill dams during construction and initial impounding using instrumentation data and numerical modeling

    Directory of Open Access Journals (Sweden)

    Mohammad Rashidi

    2017-08-01

    Full Text Available In this study, the behavior of Gavoshan dam was evaluated during construction and the first impounding. A two-dimensional (2D numerical analysis was conducted based on a finite difference method on the largest cross-section of the dam using the results of instrument measurements and back analysis. These evaluations will be completed in the case that back analysis is carried out in order to control the degree of the accuracy and the level of confidence of the measured behavior since each of the measurements could be controlled by comparing it to the result obtained from the numerical model. Following that, by comparing the results of the numerical analysis with the measured values, it is indicated that there is a proper consistency between these two values. Moreover, it was observed that the dam performance was suitable regarding the induced pore water pressure, the pore water pressure ratio ru, settlement, induced stresses, arching degree, and hydraulic fracturing probability during the construction and initial impounding periods. The results demonstrated that the maximum settlement of the core was 238 cm at the end of construction. In the following 6 years after construction (initial impounding and exploitation period, the accumulative settlement of the dam was 270 cm. It is clear that 88% of the total settlement of the dam took place during dam construction. The reason is that the clay core was smashed in the wet side, i.e. the optimum moisture content. Whereas the average curving ratio was 0.64 during dam construction; at the end of the initial impounding, the maximum amount of curving ratio in the upstream was 0.81, and the minimum (critical amount in the downstream was 0.52. It was also concluded that this dam is safe in comparison with the behaviors of other similar dams in the world.

  5. 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.

  6. Quantization function for attractive, singular potential tails

    International Nuclear Information System (INIS)

    Raab, Patrick N.

    2010-01-01

    The interaction between atoms and molecules with each other are deep potential wells with attractive, singular tails. Bound state energies are determined by a quantization function according to a simple quantization rule. This function is dominantly determined by the singular potential tail for near-threshold states. General expressions for the low- and high-energy contributions of the singular potential tail to the quantization function, as well as the connection to the scattering length are presented in two and three dimensions. Precise analytical expressions for the quantization function are determined for the case of potential tails proportional to -1/r 4 and -1/r 6 for three dimensions. (orig.)

  7. Temporal variation and spatial distribution of PAH in water of Three Gorges Reservoir during the complete impoundment period.

    Science.gov (United States)

    Wang, Jingxian; Henkelmann, Bernhard; Bi, Yonghong; Zhu, Kongxian; Pfister, Gerd; Hu, Wei; Temoka, Cedrique; Westrich, Bernhard; Schramm, Karl-Werner

    2013-10-01

    Bioavailable concentrations of polycyclic aromatic hydrocarbons (PAHs) were investigated in water of Three Gorges Reservoir (TGR) using semipermeable membrane devices during the period of completely impounding water. ∑PAH concentrations in water of TGR in the period of completely impounding water were 15-381 ng L(-1). ∑PAH concentrations increased from town or counties to big industrialized cities in TGR, indicating urbanization effects on PAH pollution in the water. Tributaries in TGR have a certain contribution of PAH pollution to the mainstream of Yangtze River and their pollution could not be neglected. An obvious decrease of PAH concentration was observed after 175-m water impounding in 2011 in TGR. Several factors may account for this decrease, including execution of comprehensive treatment and management measures in TGR, less rainfall in 2011, and sedimentation effect caused by the dam. Passive sampling method has been successfully applied in the investigation of trace PAH in water of TGR and proved to be a useful and efficient tool for the management and sustainable development of the big reservoir. The results of the study provide valuable information about PAH pollution in the whole reservoir including some tributaries, and the pollution status is dynamically related with human activities. Therefore, PAH could be used as a marker compound or indicator in the network monitoring system to surveil and trace the pollution status in TGR.

  8. [Effects of Three Gorges Reservoir impoundment on the wetland ecosystem service value of Dongting Lake, South-central China].

    Science.gov (United States)

    Li, Jing-Bao; Dai, Yong; Yin, Ri-Xin; Yang, Yan; Li, Yu-dan; Wang, Ke-ying

    2013-03-01

    Based on the field investigation and measurement, and by using the monetary method, this paper estimated the wetland ecosystem service value of Dongting Lake before and after the impoundment of Three Gorges Reservoir (in 1996 and 2010, respectively). After the impoundment, the total ecosystem service value increased from 156.69x10(8) yuan in 1996 to 177.11x10(8) yuan in 2010. The main services value in 1996 was in the order of flood storage and regulation > water storage and supply > air regulation > scientific research and education, while that in 2010 was leisure tourism > shipping transportation > air regulation > water storage and supply. In the total service value of the wetland ecosystem, the direct value associated with water decreased from 110. 85x10(8) in 1996 to 27.47x10(8) in 2010, with a decrement of 75.2%. Though the proportion of the direct value in the production and supply of material products had somewhat increase, the indirect value in ecological environment regulation and maintenance and in culture and society still maintained at about 80% of the total value. In addition to climate factors, the impoundment of Three Gorges Reservoir and the reduction of water and sediment from Yangtze River to the Lake were the crucial reasons leading to the changes of the wetland ecosystem service value of Dongting Lake.

  9. A risk assessment of water salinization during the initial impounding period of a proposed reservoir in Tianjin, China.

    Science.gov (United States)

    Zhu, Liqin; Jiang, Cuiling; Wang, Youheng; Peng, Yanmei; Zhang, Peng

    2013-09-01

    Water salinization of coastal reservoirs seriously threatens the safety of their water supply. To elucidate the mechanism of salinization and to quantitatively analyze the risk in the initial period of the impoundment of a proposed reservoir in Tianjin Binhai New Area, laboratory and field simulation experiments were implemented and integrated with the actual operation of Beitang Reservoir, which is located in the same region and has been operational for many years. The results suggested that water salinization of the proposed reservoir was mainly governed by soil saline release, evaporation and leakage. Saline release was the prevailing factor in the earlier stage of the impoundment, then the evaporation and leakage effects gradually became notable over time. By referring to the actual case of Beitang Reservoir, it was predicted that the chloride ion (Cl(-)) concentration of the water during the initial impounding period of the proposed reservoir would exceed the standard for quality of drinking water from surface water sources (250 mg L(-1)), and that the proposed reservoir had a high risk of water salinization.

  10. Evaluation of factors related to increased zooplankton biomass and altered species composition following impoundment of a Newfoundland reservoir

    International Nuclear Information System (INIS)

    Campbell, C.E.; Knoechel, R.; Copeman, D.

    1998-01-01

    An 11-year study of the zooplankton community in Cat Arm Hydroelectric Reservoir in Newfoundland was conducted to assess long-term zooplankton community dynamics in a subarctic system. Zooplankton biomass and species compositions were monitored from 1983 to 1993. The monitoring program documented the trophic evolution of the Cat Arm system as it changed from a shallow lake with short water retention time to a deep reservoir with a much lower flushing rate. Zooplankton biomass increased approximately 19-fold in the oligotrophic hydroelectric reservoir following impoundment in 1984, relative to biomass in the preexisting lake. During the first three years of impoundment, there were no increases in either phytoplankton biomass or primary productivity. Natality of the dominant cladoceran (Daphnia catawba) did not increase. Summer water retention time increased from pre-impoundment levels of 4 days in 1983 to 338 days in 1993. The study showed that zooplankton biomass was greatly correlated with water retention time, and showed no major correlation with phytoplankton biomass, primary productivity, nutrient concentrations, pH, colour, or epilimnetic temperature. It was concluded that changes in the zooplankton community in the hydroelectric reservoir were a result of decreases in losses due to washout. 41 refs., 2 tabs., 6 figs

  11. Methane oxidation and molecular characterization of methanotrophs from a former mercury mine impoundment

    Science.gov (United States)

    Baesman, Shaun; Miller, Laurence G.; Wei, Jeremy H.; Cho, Yirang; Matys, Emily D.; Summons, Roger E.; Welander, Paula V.; Oremland, Ronald S.

    2015-01-01

    The Herman Pit, once a mercury mine, is an impoundment located in an active geothermal area. Its acidic waters are permeated by hundreds of gas seeps. One seep was sampled and found to be composed of mostly CO2 with some CH4 present. The δ13CH4 value suggested a complex origin for the methane: i.e., a thermogenic component plus a biological methanogenic portion. The relatively 12C-enriched CO2 suggested a reworking of the ebullitive methane by methanotrophic bacteria. Therefore, we tested bottom sediments for their ability to consume methane by conducting aerobic incubations of slurried materials. Methane was removed from the headspace of live slurries, and subsequent additions of methane resulted in faster removal rates. This activity could be transferred to an artificial, acidic medium, indicating the presence of acidophilic or acid-tolerant methanotrophs, the latter reinforced by the observation of maximum activity at pH = 4.5 with incubated slurries. A successful extraction of sterol and hopanoid lipids characteristic of methanotrophs was achieved, and their abundances greatly increased with increased sediment methane consumption. DNA extracted from methane-oxidizing enrichment cultures was amplified and sequenced for pmoA genes that aligned with methanotrophic members of the Gammaproteobacteria. An enrichment culture was established that grew in an acidic (pH 4.5) medium via methane oxidation.

  12. Effect of fishing effort on catch rate and catchability of largemouth bass in small impoundments

    Science.gov (United States)

    Wegener, M. G.; Schramm, Harold; Neal, J. W.; Gerard, P.D.

    2018-01-01

    Largemouth bass Micropterus salmoides (Lacepède) catch rates decline with sustained fishing effort, even without harvest. It is unclear why declines in catch rate occur, and little research has been directed at how to improve catch rate. Learning has been proposed as a reason for declining catch rate, but has never been tested on largemouth bass. If catch rate declines because fish learn to avoid lures, periods of no fishing could be a management tool for increasing catch rate. In this study, six small impoundments with established fish populations were fished for two May to October fishing seasons to evaluate the effect of fishing effort on catch rate. Closed seasons were implemented to test whether a 2‐month period of no fishing improved catch rates and to determine whether conditioning from factors other than being captured reduced catch rate. Mixed‐model analysis indicated catch rate and catchability declined throughout the fishing season. Catch rate and catchability increased after a 2‐month closure but soon declined to the lowest levels of the fishing season. These changes in catch rate and catchability support the conclusion of learned angler avoidance, but sustained catchability of fish not previously caught does not support that associative or social learning affected catchability.

  13. The Effect of Zebra Mussels on Algal Community Structure in an Impounded River System

    Science.gov (United States)

    Trumble, A. F.; Luttenton, M.

    2005-05-01

    The zebra mussel, Dreissena polymorpha, invaded the Great Lakes Region in the mid 1980's, and subsequently colonized inland lakes and coastal river systems through secondary invasions. The Muskegon River below Croton Dam was colonized by zebra mussels in 2000 following their introduction into Croton impoundment in the late 1990's. No zebra mussels were found below Croton Dam in 1999 but had increased to 25,000 m-2 by 2001. We examined the affect of zebra mussels on epilithic periphyton communities by comparing plots that were and were not colonized by zebra mussels. Chlorophyll a increased in both treatments over time but was significantly higher in control plots than in zebra mussel plots. The concentration of chlorophyll a in the control plots increased from 14 µgcm-2 to 26 µgcm-2 and the concentration in the zebra mussel plots started at 12 µgcm-2, peaked at 19 µgcm-2, and then decreased to 15 µgcm-2 over a 6 week period. In a related experiment using artificial streams, chlorophyll a increased with increasing zebra mussel density, but differences were not significant. The different trends observed between the two experiments may be explained in part by arthropod invertebrates associated with zebra mussel populations.

  14. 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...

  15. 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.

  16. 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.

  17. Impounded Marshes on Subsided Islands: Simulated Vertical Accretion, Processes, and Effects, Sacramento-San Joaquin Delta, CA USA

    Directory of Open Access Journals (Sweden)

    Steven J. Deverel

    2014-06-01

    Full Text Available There is substantial interest in stopping and reversing the effects of subsidence in the Sacramento–San Joaquin Delta (Delta where organic soils predominate. Also, the passage of California Assembly Bill 32 in 2006 created the potential to trade credits for carbon sequestered in wetlands on subsided Delta islands. The primary purpose of the work described here was to estimate future vertical accretion and understand processes that affect vertical accretion and carbon sequestration in impounded marshes on subsided Delta islands. Using a cohort-accounting model, we simulated vertical accretion from 4,700 calibrated years before present (BP at a wetland area located within Franks Tract State Recreation Area (lat 38.059, long −121.611, hereafter, “Franks Wetland”—a small, relatively undisturbed marsh island—and at the Twitchell Island subsidence-reversal demonstration project since 1997. We used physical and chemical data collected during the study as well as literature values for model inputs. Model results compared favorably with measured rates of vertical accretion, mass of carbon sequestered, bulk density and organic matter content. From 4,700 to model-estimated 350 years BP, the simulated rate of vertical accretion at Franks Wetland averaged about 0.12 cm yr-1, which is within the range of rates in tidal wetlands worldwide. Our model results indicate that large sediment inputs during the last 150 to 200 years resulted in a higher accretion rate of 0.3 cm yr -1. On Twitchell Island, greater organic inputs resulted in average vertical accretion rates as high as 9.2 cm yr -1. Future simulations indicate that the managed impounded marsh will accrete highly organic material at rates of about 3 cm yr -1. Model results coupled with GIS analysis indicate that large areas of the periphery of the Delta, if impounded and converted to freshwater marsh, could be restored to tidal elevations within 50 to 100 years. Most of the

  18. Profitable tail-end production

    Energy Technology Data Exchange (ETDEWEB)

    Pinchbeck, R.H.

    1997-12-31

    This presentation discusses the origins of the present challenge faced in making mature oil fields profitable in the North Sea. It briefly examines the origins of these challenges, which are rooted in the industrial psychology of the North Sea. It develops a methodological formula for the successful re-engineering of inefficiently-run assets, focusing in particular on the personnel management aspects. It identifies some key areas to seek sustainable cost reductions and recognises the importance of renewing the context for investment in tail-end fields. Finally, it speculates about the way in which the learnings developed in the experiences of the last few years will influence the future of the North Sea. 2 refs.

  19. Tailings treatment and nano-particles

    Energy Technology Data Exchange (ETDEWEB)

    McEachern, P.; Burkus, Z.; Yu, T.; Ulrich, A.; Zhu, D. [Alberta Environment, Edmonton, AB (Canada)

    2009-07-01

    Oil sands fluid tailings are heterodispersed colloidal and suspended particles comprised of hydrophilic clays, metal oxides, organic acids, and hydration shells that create weak gels. Approximately 3 per cent of the total tailings stream are particles less than 0.2 {mu}m. Smaller fines are mobile with a high charge, and have a reactive surface that attracts organics and heavy metals. The fines also stick to bitumen and inhibit recovery. The particles in clays in tailings are typically less than 2 {mu}m. The multivalent ion increase the tendency for gelling. Treatment processes for fluid fine tailings include flocculation, chemical oxidation, and biological fermentation oxidation processes. Large polyacrylamides are used to capture fines in cross-bridged structures, while inorganic gels are used to hold water. Exopolysaccharides are used in mature fine tailings remediation processes. Other nanotechnology processes for tailings include photo-catalyzed oxidation, ozone pre-treatment; and zero valent ion treatments. Biotreatment researchers are now exploring the use of engineered microbially-mediated wastewater treatment technologies to accelerate oil sands tailings consolidation. Organic coagulants are also being considered as a means of consolidating tailings. It was concluded that various engineering reactors are now being investigated in order to accelerate microbial transformations. tabs., figs.

  20. The big head and the long tail

    DEFF Research Database (Denmark)

    Helles, Rasmus

    2013-01-01

    on the generative mechanism behind the long–tail distribution of Web site use. The analysis shows that the long tail should be seen as a tiered version of popular top sites, and argues that downsizing of large–scale datasets in combination with qualitative and/or small–scale quantitative procedures may provide...

  1. Analysis of Heavy-Tailed Time Series

    DEFF Research Database (Denmark)

    Xie, Xiaolei

    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......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...

  2. Injurious tail biting in pigs: how can it be controlled in existing systems without tail docking?

    Science.gov (United States)

    D'Eath, R B; Arnott, G; Turner, S P; Jensen, T; Lahrmann, H P; Busch, M E; Niemi, J K; Lawrence, A B; Sandøe, P

    2014-09-01

    Tail biting is a serious animal welfare and economic problem in pig production. Tail docking, which reduces but does not eliminate tail biting, remains widespread. However, in the EU tail docking may not be used routinely, and some 'alternative' forms of pig production and certain countries do 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 investigation. The review identifies a number of knowledge gaps and promising avenues for future research into prevention and mitigation. We illustrate the diversity of hypotheses concerning how different proposed risk factors might increase tail biting through their effect on each other or on the proposed 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, manipulable natural materials can be of considerable benefit. Further comparative research is needed into materials, such as ropes, which are compatible with slatted floors. Also, materials which double as fuel for anaerobic digesters could be utilised. As well as optimising housing and management to reduce risk, it is important to detect and treat tail biting as soon as it occurs. Early warning signs before the first bloody tails appear, such as pigs holding their tails tucked

  3. 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

    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...... 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......: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...

  4. 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

    In pig production, piglets are tail docked at birth in order to prevent tail biting later in life. In order to examine the effects of tail docking and docking length on the formation of neuromas, we used 65 pigs and the following four treatments: intact tails (n=18); leaving 75% (n=17); leaving 50......% (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...... (1.0±0.2 v. 0; Piron cautery causes formation of neuromas in the outermost part of the tail tip. The presence of neuromas might lead to altered nociceptive thresholds, which need...

  5. Shake a tail feather: the evolution of the theropod tail into a stiff aerodynamic surface.

    Directory of Open Access Journals (Sweden)

    Michael Pittman

    Full Text Available Theropod dinosaurs show striking morphological and functional tail variation; e.g., a long, robust, basal theropod tail used for counterbalance, or a short, modern avian tail used as an aerodynamic surface. We used a quantitative morphological and functional analysis to reconstruct intervertebral joint stiffness in the tail along the theropod lineage to extant birds. This provides new details of the tail's morphological transformation, and for the first time quantitatively evaluates its biomechanical consequences. We observe that both dorsoventral and lateral joint stiffness decreased along the non-avian theropod lineage (between nodes Theropoda and Paraves. Our results show how the tail structure of non-avian theropods was mechanically appropriate for holding itself up against gravity and maintaining passive balance. However, as dorsoventral and lateral joint stiffness decreased, the tail may have become more effective for dynamically maintaining balance. This supports our hypothesis of a reduction of dorsoventral and lateral joint stiffness in shorter tails. Along the avian theropod lineage (Avialae to crown group birds, dorsoventral and lateral joint stiffness increased overall, which appears to contradict our null expectation. We infer that this departure in joint stiffness is specific to the tail's aerodynamic role and the functional constraints imposed by it. Increased dorsoventral and lateral joint stiffness may have facilitated a gradually improved capacity to lift, depress, and swing the tail. The associated morphological changes should have resulted in a tail capable of producing larger muscular forces to utilise larger lift forces in flight. Improved joint mobility in neornithine birds potentially permitted an increase in the range of lift force vector orientations, which might have improved flight proficiency and manoeuvrability. The tail morphology of modern birds with tail fanning capabilities originated in early ornithuromorph

  6. A microbial arsenic cycle in sediments of an acidic mine impoundment: Herman Pit, Clear Lake, California

    Science.gov (United States)

    Blum, Jodi S.; McCann, Shelley; Bennett, S.; Miller, Laurence G.; Stolz, J. R.; Stoneburner, B.; Saltikov, C.; Oremland, Ronald S.

    2015-01-01

    The involvement of prokaryotes in the redox reactions of arsenic occurring between its +5 [arsenate; As(V)] and +3 [arsenite; As(III)] oxidation states has been well established. Most research to date has focused upon circum-neutral pH environments (e.g., freshwater or estuarine sediments) or arsenic-rich “extreme” environments like hot springs and soda lakes. In contrast, relatively little work has been conducted in acidic environments. With this in mind we conducted experiments with sediments taken from the Herman Pit, an acid mine drainage impoundment of a former mercury (cinnabar) mine. Due to the large adsorptive capacity of the abundant Fe(III)-rich minerals, we were unable to initially detect in solution either As(V) or As(III) added to the aqueous phase of live sediment slurries or autoclaved controls, although the former consumed added electron donors (i.e., lactate, acetate, hydrogen), while the latter did not. This prompted us to conduct further experiments with diluted slurries using the live materials from the first incubation as inoculum. In these experiments we observed reduction of As(V) to As(III) under anoxic conditions and reduction rates were enhanced by addition of electron donors. We also observed oxidation of As(III) to As(V) in oxic slurries as well as in anoxic slurries amended with nitrate. We noted an acid-tolerant trend for sediment slurries in the cases of As(III) oxidation (aerobic and anaerobic) as well as for anaerobic As(V) reduction. These observations indicate the presence of a viable microbial arsenic redox cycle in the sediments of this extreme environment, a result reinforced by the successful amplification of arsenic functional genes (aioA, and arrA) from these materials.

  7. Destratification of an impounding reservoir using compressed air??case of Mudi reservoir, Blantyre, Malawi

    Science.gov (United States)

    Chipofya, V. H.; Matapa, E. J.

    This paper reviews the operational and cost effectiveness of a compressed air destratification system that was installed in the Mudi reservoir for destratifying the reservoir. Mudi reservoir is a raw water source for the Blantyre Water Board. It has a capacity of 1,400,000 cubic metres. The reservoir is 15.3 m deep at top water level. In the absence of any artificial circulation of air, the reservoir stratifies into two layers. There is a warm epilimnion in the top 3 m of the reservoir, with temperatures ranging from 23 to 26 °C. There is prolific algal growth in this layer. The bottom layer has much lower temperatures, and is oxygen deficient. Under such anaerobic conditions, ammonia, sulphides, iron and manganese are released from the sediments of the reservoir. As a result of nutrient inflow from the catchments, coupled with tropical ambient temperatures, the reservoir is most times infested with blue-green algae. This results into water treatment problems in respect of taste and odour and iron and manganese soluble salts. To abate such problems, air is artificially circulated in the reservoir, near the intake tower, through a perforated pipe that is connected to an electrically driven compressor. This causes artificial circulation of water in the hypolimnion region of the reservoir. As a result of this circulation, a hostile environment that inhibits the propagation of algae is created. Dissolved oxygen and temperature profiles are practically uniform from top to bottom of reservoir. Concentrations of iron and manganese soluble salts are much reduced at any of the draw-off points available for the water treatment process. The paper concludes by highlighting the significant cost savings in water treatment that are accrued from the use of compressed air destratification in impounding water storage reservoirs for the control of algae and other chemical pollutants.

  8. Limnology and fisheries of three recently impounded reservoirs in Sri Lanka

    International Nuclear Information System (INIS)

    Silva, K.H.G.M De

    1990-01-01

    The hydroelectric reservoirs of Kotmale, Victoria, and Randenigala were impounded in 1985, 1984, and 1986, respectively, by damming the Mahaweli River. The surface area, maximum depth, and mean depth of the three reservoirs are 6.3 km 2 , 78 m, 27.6 m; 23.7 km 2 , 102 m, 30.8 m; and 23.5 km 2 , 90 m, 36.6 m respectively, at their full supply levels of 703, 438, and 232 m above mean sea level. Important physicochemical factors and phytoplankton were studied by sampling of subsurface waters every two weeks in 12 randomly chosen stations in Randenigala and Victoria, and in 10 stations in Kotmale over 24 months. Mean water temperature, pH, conductivity, and the total alkalinity during the study period were 25.6 degree C, 6.6, 50.7 μsieverts, and 0.31 millimoles/l in Kotmale, 26.9 degree C, 7.1, 77.4 μsieverts, and 0.62 millimoles/l in Victoria, and 28.3 degree C, 7.4, 90.0 μsieverts, and 0.79 millimoles/l in Randenigala. The gill-net catches of Kotmale and Victoria are ca 38 and 70 kg/hectare/y, respectively. Randenigala has a fishery potential of ca 70 kg/hectare/y. Tilapia formed ca 68%, 59%, and 69% of the catches of Kotmale, Victoria, and Randenigala, respectively. The catch at Kotmale was mainly Java tilapia and Nile tilapia, whereas at the other two reservoirs it was mainly Java tilapia. Indigenous species constituted only ca 10% of the catch. 16 refs., 2 figs., 4 tabs

  9. Coal combustion waste management at landfills and surface impoundments 1994-2004.

    Energy Technology Data Exchange (ETDEWEB)

    Elcock, D.; Ranek, N. L.; Environmental Science Division

    2006-09-08

    On May 22, 2000, as required by Congress in its 1980 Amendments to the Resource Conservation and Recovery Act (RCRA), the U.S. Environmental Protection Agency (EPA) issued a Regulatory Determination on Wastes from the Combustion of Fossil Fuels. On the basis of information contained in its 1999 Report to Congress: Wastes from the Combustion of Fossil Fuels, the EPA concluded that coal combustion wastes (CCWs), also known as coal combustion by-products (CCBs), did not warrant regulation under Subtitle C of RCRA, and it retained the existing hazardous waste exemption for these materials under RCRA Section 3001(b)(3)(C). However, the EPA also determined that national regulations under Subtitle D of RCRA were warranted for CCWs that are disposed of in landfills or surface impoundments. The EPA made this determination in part on the basis of its findings that 'present disposal practices are such that, in 1995, these wastes were being managed in 40 percent to 70 percent of landfills and surface impoundments without reasonable controls in place, particularly in the area of groundwater monitoring; and while there have been substantive improvements in state regulatory programs, we have also identified gaps in State oversight' (EPA 2000). The 1999 Report to Congress (RTC), however, may not have reflected the changes in CCW disposal practices that occurred since the cutoff date (1995) of its database and subsequent developments. The U.S. Department of Energy (DOE) and the EPA discussed this issue and decided to conduct a joint DOE/EPA study to collect new information on the recent CCW management practices by the power industry. It was agreed that such information would provide a perspective on the chronological adoption of control measures in CCW units based on State regulations. A team of experts from the EPA, industry, and DOE (with support from Argonne National Laboratory) was established to develop a mutually acceptable approach for collecting and analyzing data

  10. 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.

  11. 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).

  12. Tail-biting: a new perspective.

    Science.gov (United States)

    Taylor, Nina R; Main, David C J; Mendl, Mike; Edwards, Sandra A

    2010-11-01

    Tail-biting data from different studies are difficult to compare because a range of definitions of tail-biting behaviour and tail-biting lesions are used. Although records from abattoirs provide a large database, their usefulness is restricted as tail-biting is under-recorded and environmental and husbandry factors associated with the behaviour are unlikely to be known. Both farm and abattoir data provide no information on the number of pigs biting, only those bitten. Studying individual animals that tail-bite should give a better understanding of the pig's motivation to tail-bite and which of the components of its environment should be adjusted to improve welfare. This review examines the existing literature on tail-biting in pigs but considered from a new perspective using three different descriptive behavioural types, namely, 'two-stage', 'sudden-forceful' and 'obsessive', each of which may have different motivational bases. The article also considers the different environmental and husbandry factors which may affect each type of behaviour and discusses why this is such a complicated field and why it is often difficult to draw conclusions from available research. Copyright © 2009 Elsevier Ltd. All rights reserved.

  13. 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.

  14. 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

  15. Analysis of Wading Bird use of Impounded Wetland Habitat on the Kennedy Space Center/Merritt Island National Wildlife Refuge, 1987-1998

    Science.gov (United States)

    Stolen, Eric D.; Breininger, David R.; Smith, Rebecca B.; Quincy, Charlie (Technical Monitor)

    2002-01-01

    This report summarizes results of the first eleven years of monthly aerial surveys of wading bird use of foraging habitats within impoundments on the Kennedy Space Center/Merritt Island National Wildlife Refuge. Some impoundments were used much more heavily by wading birds than were others. Analysis suggests that an increase in interspersion of open water and vegetated habitats is preferred foraging habitat. Many wading bird species increased their use of vegetated habitat in Fall and Winter when impoundments were flooded. The mean number of wading birds per survey was greatest during the Pre-nesting and Nesting seasons, declined during Post-nesting season, and was lowest during Winter when water levels within impoundments were high. During these times, shallow habitat along the IRL shoreline provided alternative habitats for wading birds. Various measures of monthly precipitation and impoundment water level were well correlated with the numbers of wading birds observed. Numbers of nesting attempts was steady during the study period, with the exception of an unusually high number of attempts in 1990. White Ibis accounted for over half of all wading bird nests counted. The mean number of nests per colony decreased during the study period, and the number of individual colonies increased.

  16. Sharptooth catfish shows its metal: a case study of metal contamination at two impoundments in the Olifants River, Limpopo river system, South Africa.

    Science.gov (United States)

    Jooste, Antoinette; Marr, Sean M; Addo-Bediako, Abraham; Luus-Powell, Wilmien J

    2015-02-01

    Clarias gariepinus is increasing in importance as a global aquaculture species with a 100 fold increase in production over the past decade but this species still remains one of the most important wild harvested freshwater food fish throughout rural Africa. However, this species has been shown to accumulate metals from contaminated inland waters. In this paper, the metal concentrations in muscle tissue of C. gariepinus from two main-stem impoundments in the Olifants River, Limpopo Basin, were measured and a desktop risk assessment based on the US-EPA methodology completed to evaluate whether long-term consumption of C. gariepinus from these impoundments may pose a health risk to rural communities. Our results show that metals are accumulating in the muscle tissue of C. gariepinus and have appeared to have increased in the last two decades. Risk assessment generated Hazard quotients (HQ) greater than 1 indicate that long term consumption of fish from these impoundments may cause adverse health impacts. We found that lead (HQ=9), antimony (HQ=14), cobalt (HQ=2) and chromium (HQ=1) at one impoundment and lead (HQ=2) at the other impoundment were above acceptable levels for weekly consumption of 150 g C. gariepinus muscle tissue. Copyright © 2014 Elsevier Inc. All rights reserved.

  17. Influences of local habitat, tributary position, and dam characteristics on fish assemblages within impoundments of low-head dams in the tributaries of the Qingyi River, China.

    Science.gov (United States)

    Li, Xian; Li, Yu-Ru; Chu, Ling; Zhu, Ren; Wang, Li-Zhu; Yan, Yun-Zhi

    2016-03-18

    Low-head dam impoundments modify local habitat and alter fish assemblages; however, to our knowledge, the pattern of how fish assemblages in the impoundments relate to local habitat, tributary position, and dam characteristics is still unclear. We used data collected in 62 impoundments created by low-head dams in headwater streams of the Qingyi River, China, to examine relationships between fish assemblages and local habitat, tributary position, and dam characteristics. We also assessed the relative importance of the three groups of factors in determining fish species richness and composition. Linear regression models showed that fish species richness was related to substrate heterogeneity, confluence link, and dam number upstream. Redundancy analysis showed that fish species compositions were influenced by substrate heterogeneity, confluence link, dam height, dam numbers upstream and downstream. Overall, dam characteristics were more important in affecting fish species richness but less important in determining fish species composition than local habitat (i.e., substrate heterogeneity) and tributary position. Our results suggest that low-head dam may affect fish species richness in impoundments by modifying local habitat and constraining fish movement, and the relative abundances of those fish species may depend more on species habitat presences and stream size than on impoundment size and number.

  18. The long term stabilization of uranium mill tailings. Final report of a co-ordinated research project 2000-2004

    International Nuclear Information System (INIS)

    2004-08-01

    Mining and milling of uranium ores has been undertaken in many places around the world, resulting in large volumes of mining/milling residues with low activity concentrations of long lived nuclides that often have been disposed of in a haphazard fashion. This report summarizes the current state of the art of uranium mill tailings disposal and the results from an IAEA Coordinated Research Project (CRP) on technologies and strategies for their long term stabilization. The aim of the CRP was to develop conceptual and technical solutions that render tailings more inert over prolonged time spans, that render impounded materials and engineered structures stable over prolonged time spans, that minimize the need for active maintenance, and that are technically and economically feasible. The emphasis was on solutions that can be applied retrospectively, i.e. in a restoration/remediation context. It was recognized, however, that these objectives cannot be met by engineering design only, but must also involve appropriate management and planning procedures. Present day practices and new approaches of Brazil, Canada, China, Czech Republic, France, Germany, Kazakhstan, the Republic of Korea, Poland, the Russian Federation, Ukraine and the United States are discussed and indexed individually

  19. Remediation strategy, capping construction and ongoing monitoring for the mill tailings pond, Ningyo-Toge uranium mine, Japan

    International Nuclear Information System (INIS)

    Hiroshi Saito; Tomihiro Taki

    2013-01-01

    Ningyo-toge Uranium Mine is subject to the environmental remediation. The main purposes are to take measures to ensure the radiation protection from the exposure pathways to humans in future, and to prevent the occurrence of mining pollution. The Yotsugi Mill Tailings Pond in the Ningyo-toge Uranium Mine has deposited mining waste and impounded water as a buffer reservoir before it is transferred to the Water Treatment Facility. It is located at the upstream of the water-source river and as the impact on its environment in case of earthquake is estimated significant, the highest priority has been put to it among mine-related facilities in the Mine. So far, basic concept has been examined and a great number of data has been acquired, and using the data, some remediation activities have already done, including capping construction for the upstream part of the Mill Tailings Pond. The capping is to reduce rainwater penetration to lower the burden of water treatment, and to reduce radon exhalation and dose rates. Only natural materials are used to alleviate the future maintenance. Data, including settlement amount and underground temperature is now being acquired and accumulated to verify the effectiveness of the capping, and used for the future remediation of the Downstream with revision of its specifications if necessary. (authors)

  20. Remedial Action Plan and site design for stabilization of the inactive uranium mill tailings site at Gunnison, Colorado

    International Nuclear Information System (INIS)

    1992-10-01

    Diffusion coefficients for radon gas in earthen materials are required to design suitable radon-barrier covers for uranium tailings impoundments and other materials that emit radon gas. Many early measurements of radon diffusion coefficients relied on the differences in steady-state radon fluxes measured from radon source before and after installation of a cover layer of the material being tested. More recent measurements have utilized the small-sample transient (SST) technique for greater control on moistures and densities of the test soils, greater measurement precision, and reduced testing time and costs. Several of the project sites for the US Department of Energy's Uranium Mill Tailings Remedial Action (UMTRA) Program contain radiologically contaminated subsurface material composed predominantly of cobbles, gravels andsands. Since remedial action designs require radon diffusion coefficients for the source materials as well as the cover materials, these cobbly and gravelly materials also must be tested. This report contains the following information: a description of the test materials used and the methods developed to conduct the SST radon diffusion measurements on cobbly soils; the protocol for conducting radon diffusion tests oncobbly soils; the results of measurements on the test samples; and modifications to the FITS computer code for analyzing the time-dependent radon diffusion data

  1. 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)

  2. Hovercraft drill probes Saraji tailings dam

    Energy Technology Data Exchange (ETDEWEB)

    1991-09-01

    In early operations at BHP-Utah's Saraji Mine in central Queensland, quantities of coking coal were pumped into the tailings dam because the preparation plant's flotation circuit was unable to handle ultra-fines. A reverse circulating drilling rig mounted on a hovercraft was used to recover 22 samples (representing 9 metres of tailings from 11 x 8 x 0.09 metre cores) in an investigation into whether the tailings can now be treated economically. 1 fig.

  3. Evaluating the effect of vehicle impoundment policy on illegal construction and demolition waste dumping: Israel as a case study.

    Science.gov (United States)

    Seror, Nissim; Hareli, Shlomo; Portnov, Boris A

    2014-08-01

    Construction and demolition (C&D) waste dumped alongside roads and in open areas is a major source of soil and underground water pollution. Since 2006, Israeli ministry for environmental protection enacted a policy of vehicle impoundment (VI) according to which track drivers caught while dumping C&D waste illegally have their vehicles impounded. The present study attempted to determine whether the VI policy was effective in increasing the waste hauling to authorized landfill sites, thus limiting the number of illegal unloads of C&D waste at unauthorized landfill sites and in open areas. During the study, changes in the ratio between the monthly amount of C&D waste brought to authorized landfills sites and the estimated total amount of C&D waste generated in different administrative districts of Israel were examined, before and after the enactment of the 2006 VI policy. Short questionnaires were also distributed among local track drivers in order to determine the degree of awareness about the policy in question and estimate its deterrence effects. According to the study's results, in the district of Haifa, in which the VI policy was stringently enacted, the ratio between C&D waste, dumped in authorized landfill sites, and the total amount of generated C&D waste, increased, on the average, from 20% in January 2004 to 35% in October 2009, with the effect attributed to the number of vehicle impoundments being highly statistically significant (t=2.324; p0.1). The analysis of the questionnaires, distributed among the local truck drivers further indicated that the changes observed in the district of Haifa are not coincident and appeared to be linked to the VI policy's enactment. In particular, 62% of the truck drivers, participated in the survey, were aware of the policy and 47% of them personally knew a driver whose vehicle was impounded. Furthermore, the drivers estimated the relative risk of being caught for unloading C&D waste in unauthorized sites, on the average, as

  4. 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)

  5. White-tailed deer in the Midwest.

    Science.gov (United States)

    USDA FS

    1970-01-01

    Discusses the present status and future prospects of the nonyarding white-tailed deer population in the Midwestern United States. Range appraisal, habitat, harvest regulation, and population control are included.

  6. 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.

  7. On Estimation and Testing for Pareto Tails

    Czech Academy of Sciences Publication Activity Database

    Jordanova, P.; Stehlík, M.; Fabián, Zdeněk; Střelec, L.

    2013-01-01

    Roč. 22, č. 1 (2013), s. 89-108 ISSN 0204-9805 Institutional support: RVO:67985807 Keywords : testing against heavy tails * asymptotic properties of estimators * point estimation Subject RIV: BB - Applied Statistics, Operational Research

  8. 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....

  9. Unique Structural Features Facilitate Lizard Tail Autotomy

    DEFF Research Database (Denmark)

    Sanggaard, Kristian Wejse; Danielsen, C. C.; Wogensen, L.

    2012-01-01

    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....

  10. 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.

  11. 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

  12. Hydrologic Change during the Colonial Era of the United States: Beavers and the Energy Cost of Impoundments (Invited)

    Science.gov (United States)

    Green, M. B.; Bain, D. J.; Arrigo, J. S.; Duncan, J. M.; Kumar, S.; Parolari, A.; Salant, N.; Vorosmarty, C. J.; Aloysius, N. R.; Bray, E. N.; Ruffing, C. M.; Witherell, B. B.

    2009-12-01

    Europeans colonized North America in the early 17th century with intentions ranging between long-term inhabitation and quick extraction of resources for economic gain in Europe. Whatever the intentions, the colonists relied on the landscape for resources resulting in dramatic change to the forest and fur-bearing mammal population. We demonstrate that initial exploitation of North American forest and furs caused a substantial decrease in mean water residence time (τ) between 1600 and 1800 A.D. That loss, which regionally changed from 51 to 41 days, contrasts with conventional wisdom that humans tend to diminish variability in water resources by increasing storage capacity and thus increasing τ. The loss of τ resulted from over-hunted beaver for the hat market in Europe. Analysis suggests that colonial era demographics and economics did not allow human resource allocation to impoundment construction on a level matching the historic beaver effort. However, the τ appears to have regionally increased during the 19th century, suggesting that humans eventually began replacing the water storage lost with the beaver. The analysis highlights the energy cost of impounding water, which is likely to continue to be an important factor given the increasing need for stable water resources and finite energy resources.

  13. Microcrustaceans (Branchiopoda and Copepoda) of Wetland Ponds and Impoundments on the Savannah River Site, Aiken, South Carolina

    Energy Technology Data Exchange (ETDEWEB)

    Adrienne E. DeBiase; Barbara E. Taylor

    2005-09-21

    The United States Department of Energy's Savannah River Site (SRS) in Aiken, Allendale, and Barnwell Counties, South Carolina, contains an abundance of freshwater wetlands and impoundments. Four large impoundments, as well as several small, abandoned farm and mill ponds, and about 400 Carolina bays and other small, isolated depression wetland ponds are located within the 893 km2 area of the SRS. Crustaceans of the orders Branchiopoda and Copepoda are nearly ubiquitous in these water bodies. Although small in size, these organisms are often very abundant. They consequently play an important trophic role in freshwater food webs supporting fish, larval salamanders, larval insects, and numerous other animals, aquatic and terrestrial. This report provides an introduction to the free-living microcrustaceans of lentic water bodies on the SRS and a comprehensive list of species known to occur there. Occurrence patterns are summarized from three extensive survey studies, supplemented with other published and unpublished records. In lieu of a key, we provide a guide to taxonomic resources and notes on undescribed species. Taxa covered include the orders Cladocera, Anostraca, Laevicaudata, and Spinicaudata of the Subclass Branchiopoda and the Superorders Calanoida and Cyclopoida of Subclass Copepoda. Microcrustaceans of the Superorder Harpacticoida of the Subclass Copepoda and Subclass Ostracoda are also often present in lentic water bodies. They are excluded from this report because they have not received much study at the species level on the SRS.

  14. 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

  15. Sediment transport to and from small impoundments in northeast Kansas, March 2009 through September 2011

    Science.gov (United States)

    Foster, Guy M.; Lee, Casey J.; Ziegler, Andrew C.

    2012-01-01

    The U.S. Geological Survey, in cooperation with the Kansas Water Office, investigated sediment transport to and from three small impoundments (average surface area of 0.1 to 0.8 square miles) in northeast Kansas during March 2009 through September 2011. Streamgages and continuous turbidity sensors were operated upstream and downstream from Atchison County, Banner Creek, and Centralia Lakes to study the effect of varied watershed characteristics and agricultural practices on sediment transport in small watersheds in northeast Kansas. Atchison County Lake is located in a predominantly agricultural basin of row crops, with wide riparian buffers along streams, a substantial amount of tile drainage, and numerous small impoundments (less than 0.05 square miles; hereafter referred to as “ponds”). Banner Creek Lake is a predominantly grassland basin with numerous small ponds located in the watershed, and wide riparian buffers along streams. Centralia Lake is a predominantly agricultural basin of row crops with few ponds, few riparian buffers along streams, and minimal tile drainage. Upstream from Atchison County, Banner Creek, and Centralia Lakes 24, 38, and 32 percent, respectively, of the total load was transported during less than 0.1 percent (approximately 0.9 days) of the time. Despite less streamflow in 2011, larger sediment loads during that year indicate that not all storm events transport the same amount of sediment; larger, extreme storms during the spring may transport much larger sediment loads in small Kansas watersheds. Annual sediment yields were 360, 400, and 970 tons per square mile per year at Atchison County, Banner, and Centralia Lake watersheds, respectively, which were less than estimated yields for this area of Kansas (between 2,000 and 5,000 tons per square mile per year). Although Centralia and Atchison County Lakes had similar percentages of agricultural land use, mean annual sediment yields upstream from Centralia Lake were about 2.7 times

  16. Social Cost of Tail Loss in Uta stansburiand.

    Science.gov (United States)

    Fox, S F; Rostker, M A

    1982-11-12

    Tail removal from dominant juvenile Uta stansburiana resulted in a decrease in social status in dyadic encounters. Most lizards were affected after removal of two-thirds of their tails. In some pairs, dominant lizards lost status after removal of one-third of their tails but regained dominance after the other member of the pair lost two-thirds of its tail. Tail loss in nature may impose a social handicap to successful home range acquisition and thereby increase risk of death.

  17. Single-Tailed Lipidoids Enhance the Transfection Activity of Their Double-Tailed Counterparts.

    Science.gov (United States)

    Wu, Yihang; Li, Linxian; Chen, Qing; Su, Yi; Levkin, Pavel A; Davidson, Gary

    2016-01-11

    Cationic lipid-like molecules (lipidoids) are widely used for in vitro and in vivo gene delivery. Nearly all lipidoids developed to date employ double-tail or multiple-tail structures for transfection. Single-tail lipidoids are seldom considered for transfection as they have low efficiency in gene delivery. So far, there is no detailed study on the contribution to transfection efficiency of single-tail lipidoids when combined with standard double-tail lipidoids. Here, we use combinatorial chemistry to synthesize 17 double-tail and 17 single-tail lipidoids using thiol-yne and thiol-ene click chemistry, respectively. HEK 293T cells were used to analyze transfection efficiency by fluorescence microscopy and calculated based on the percentage of cells transfected. The size and zeta potential of liposomes and lipoplexes were characterized by dynamic light scattering (DLS). Intracellular DNA delivery and trafficking was further examined using confocal microscopy. Our study shows that combining single with double-tail lipidoids increases uptake of lipoplexes, as well as cellular transfection efficiency.

  18. Generalized processor sharing with light-tailed and heavy-tailed input

    NARCIS (Netherlands)

    Borst, Sem; Mandjes, M.R.H.; van Uitert, Miranda

    2003-01-01

    We consider a queue fed by a mixture of light-tailed and heavy-tailed traffic. The two traffic flows are served in accordance with the generalized processor sharing (GPS) discipline. GPS-based scheduling algorithms, such as weighted fair queueing, have emerged as an important mechanism for achieving

  19. 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

  20. 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 an...

  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. Hydrogeochemical studies on WTC uranium tailings lysimeters

    International Nuclear Information System (INIS)

    1983-03-01

    In 1974, Environment Canada initiated a series of tailings lysimeter studies at the Wastewater Technology Centre (WTC) in Burlington, Ontario, to examine the leachability of radionuclides and major constituents (TDS, pH) from uranium mill tailings. In addition, the study attempted to assess the effect of two leachate control methods (chemical fixation and vegetation) upon the characteristics of tailings leachate. In 1982 IEC Beak Consultants Ltd. was retained to conduct additional physical/chemical characterization of the tailings solids and some leachate samples. This information, together with the existing data, was then used to develop a conceptual model with which to try to explain the behaviour of the tailings during the leaching of the lysimeters. The specific tasks undertaken included: multi-parameter analysis of leachates collected from 4 lysimeters over the last 1 1/2 years of operation; physical/chemical characterization of the final lysimeter solids including grain size, bulk density, sulphate and carbonate con-tent; use of Scanning Electron Microscopy (SEM) coupled with X-ray Emission (XRE) spectroscopy, plus Mossbauer spectroscopy to characterize surface precipitates and iron speciation respectively; chemical equilibrium modelling on leachates to estimate controlling species in radioisotope and TDS release

  3. 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

  4. Application of mineral liberation analysis in studying micro-sedimentological structures within sulfide mine tailings and their effect on hardpan formation.

    Science.gov (United States)

    Redwan, Mostafa; Rammlmair, Dieter; Meima, Jeannet A

    2012-01-01

    In this paper, mineral liberation analysis (MLA) was applied as a new approach to elucidate and quantify textural, mineralogical, and chemical variations on a μm/mm scale to understand the alteration processes relevant for hardpan formation at the Davidschacht mine tailings in Freiberg, Germany. Additionally, the bulk mineralogical, geochemical, and physical properties were investigated in detail. Within the upper 1.5m of this impoundment, a repetition was observed of oxidized sediments with pH values between 2 and 3, and of unoxidized sulfide/carbonate bearing sediments with pH values around 7.0. The alteration process was not homogeneous, as even within the same lamina different stages of oxidation were observed. According to the MLA measurements, the 2D pore area decreased from about 43 area-% in the unoxidized layers to 10.5-24.0 area-% in the hardpan layers, which is due to the accumulation of secondary precipitates. This clogging of pores was localized at the contact zone between two graded layers. The upper part of the lower layer consisted of very fine grained mica and chlorite fragments, which have a relatively high water retention capacity. This lamina was overlain by the bottom part of the next graded layer, which was characterized as relatively coarse grained with coarse open pores and an elevated content of primary reactive sulfides. This lamina provides access to oxygen and rain water to stimulate reactions, eventually supported by microbiological activity. Since graded layers might be amputated at top or bottom, the above described assemblage was not ubiquitous, but nevertheless multiple repetitions were encountered even at thin section level. The occurrence of these repetitions of slightly inclined tile like hardpans may reduce rain water and oxygen input at the rim of the impoundment. The application of MLA has opened up new opportunities for a better understanding of the sedimentological and mineralogical setup in relation to oxidation, transport

  5. Tree growth studies on uranium mill tailings

    International Nuclear Information System (INIS)

    Murray, D.R.; Turcotte, M.

    1982-01-01

    Coniferous trees planted in 1974 and deciduous species that have volunteered since 1970 on uranium mill tailings that had been stabilized to varying degrees using limestone and vegetation were evaluated. Their survival and growth rates were compared with those from other investigations. Competition for light appears to be a major contributor to mortality. Differences in soil moisture conditions under a tree stand as compared to those under a grass sward are potentially significant enough to affect the tailings hydrology and effluent contamination. Recommendations include planting seeds of deciduous species or deciduous and coniferous seedlings on strips of freshly disturbed tailings. The disturbed strips would provide reduced competition for the initial year and assist in tree survival. The planting of block stands of coniferous or deciduous trees would be useful for evaluating the hydrological impact of the trees as compared to the present grass sward

  6. Results of the measurement survey of elevation and environmental media in surface impoundments 3513 (B) and 3524 (A) at Oak Ridge National Laboratory, Oak Ridge, TN

    Energy Technology Data Exchange (ETDEWEB)

    Murray, M.E.; Rose, D.A.; Brown, K.S.; Coe, R.H.C. III; Lawrence, J.D.; Winton, W.

    1998-07-01

    A measurement survey of the elevation and environmental media in impoundments 3513 (B) and 3524 (A) at the Oak Ridge National Laboratory (ORNL) was conducted during April 1998. The investigation was performed by the Measurement Applications and Development Group of the Life Sciences Division of ORNL at the request of Bechtel Jacobs Company. Measurement activities were conducted at selected locations in order to determine the depth and appearance of the sediment and describe the clay underlying the impoundments prior to remediation. The survey was a follow-up to a previous elevation survey. The survey included the following: collection of sediment/clay cores from selected locations in each impoundment; measurement and documentation of the elevation at the water surface, at the top of sediment, at the top of clay, and at the bottom of each core; visual inspection of each core by a soil scientist to confirm the presence of clay and not material such as fly ash and soda lime compacted over the last 50 years; measurement and documentation of the background beta-gamma radiation level at the time and location of collection of each core, the highest beta-gamma level along the sediment portion of each core, and the highest beta-gamma level along the clay portion of each core; measurement and documentation of the length of the clay and of the sediment portion of each core; photographic documentation of each core; and replacement of each core in the impoundment.

  7. Results of the radiological and chemical characterization of surface impoundments 3539 and 3540 at Oak Ridge National Laboratory, Oak Ridge, Tennessee

    Energy Technology Data Exchange (ETDEWEB)

    Murray, M.E.; Rose, D.A.; Brown, K.S.; Winton, W.; Dean, R.A.; Coe, R.H. III

    1998-03-01

    A radiological and chemical characterization survey of impoundments 3539 and 3540 at the Oak Ridge National Laboratory (ORNL) was conducted during December 1997. Impoundments 3539 and 3540 are located in the Surface Impoundments Operable Unit (SIOU) of Waste Area Group 1. The investigation was performed by the Measurement Applications and Development Group of the Life Sciences Division of ORNL at the request of the Department of Energy (DOE) Office of Environmental Restoration. Sampling was conducted in order to quantify the presence of polychlorinated biphenyls (PCBs), Resource Conservation and Recovery Act (RCRA) constituents, and other contaminants of interest in support of the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) remediation for the SIOU> The survey included collection of sediment/clay samples, quality control blank water samples and equipment rinsate samples for chemical and radiological analysis. Results show the samples contain traces of various organic, inorganic, and radioactive materials. Of particular interest are PCB values which demonstrate the impoundments are not regulated under the Toxic Substances Control Act.

  8. Results of the measurement survey of elevation and environmental media in surface impoundments 3513 (B) and 3524 (A) at Oak Ridge National Laboratory, Oak Ridge, Tennessee

    International Nuclear Information System (INIS)

    Murray, M.E.; Rose, D.A.; Brown, K.S.; Coe, R.H.C. III; Lawrence, J.D.; Winton, W.

    1998-07-01

    A measurement survey of the elevation and environmental media in impoundments 3513 (B) and 3524 (A) at the Oak Ridge National Laboratory (ORNL) was conducted during April 1998. The investigation was performed by the Measurement Applications and Development Group of the Life Sciences Division of ORNL at the request of Bechtel Jacobs Company. Measurement activities were conducted at selected locations in order to determine the depth and appearance of the sediment and describe the clay underlying the impoundments prior to remediation. The survey was a follow-up to a previous elevation survey. The survey included the following: collection of sediment/clay cores from selected locations in each impoundment; measurement and documentation of the elevation at the water surface, at the top of sediment, at the top of clay, and at the bottom of each core; visual inspection of each core by a soil scientist to confirm the presence of clay and not material such as fly ash and soda lime compacted over the last 50 years; measurement and documentation of the background beta-gamma radiation level at the time and location of collection of each core, the highest beta-gamma level along the sediment portion of each core, and the highest beta-gamma level along the clay portion of each core; measurement and documentation of the length of the clay and of the sediment portion of each core; photographic documentation of each core; and replacement of each core in the impoundment

  9. Results of the radiological and chemical characterization of surface impoundments 3539 and 3540 at Oak Ridge National Laboratory, Oak Ridge, Tennessee

    International Nuclear Information System (INIS)

    Murray, M.E.; Rose, D.A.; Brown, K.S.; Winton, W.; Dean, R.A.; Coe, R.H. III

    1998-03-01

    A radiological and chemical characterization survey of impoundments 3539 and 3540 at the Oak Ridge National Laboratory (ORNL) was conducted during December 1997. Impoundments 3539 and 3540 are located in the Surface Impoundments Operable Unit (SIOU) of Waste Area Group 1. The investigation was performed by the Measurement Applications and Development Group of the Life Sciences Division of ORNL at the request of the Department of Energy (DOE) Office of Environmental Restoration. Sampling was conducted in order to quantify the presence of polychlorinated biphenyls (PCBs), Resource Conservation and Recovery Act (RCRA) constituents, and other contaminants of interest in support of the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) remediation for the SIOU> The survey included collection of sediment/clay samples, quality control blank water samples and equipment rinsate samples for chemical and radiological analysis. Results show the samples contain traces of various organic, inorganic, and radioactive materials. Of particular interest are PCB values which demonstrate the impoundments are not regulated under the Toxic Substances Control Act

  10. A long-term comparison of carbon sequestration rates in impounded and naturally tidal freshwater marshes along the lower Waccamaw River, South Carolina

    Science.gov (United States)

    Drexler, Judith Z.; Krauss, Ken W.; Sasser, M. Craig; Fuller, Christopher C.; Swarzenski, Christopher M.; Powell, Amber; Swanson, Kathleen M.; Orlando, James L.

    2013-01-01

    Carbon storage was compared between impounded and naturally tidal freshwater marshes along the Lower Waccamaw River in South Carolina, USA. Soil cores were collected in (1) naturally tidal, (2) moist soil (impounded, seasonally drained since ~1970), and (3) deeply flooded “treatments” (impounded, flooded to ~90 cm since ~2002). Cores were analyzed for % organic carbon, % total carbon, bulk density, and 210Pb and 137Cs for dating purposes. Carbon sequestration rates ranged from 25 to 200 g C m−2 yr−1 (moist soil), 80–435 g C m−2 yr−1 (naturally tidal), and 100–250 g C m−2 yr−1 (deeply flooded). The moist soil and naturally tidal treatments were compared over a period of 40 years. The naturally tidal treatment had significantly higher carbon storage (mean = 219 g C m−2 yr−1 vs. mean = 91 g C m−2 yr−1) and four times the vertical accretion rate (mean = 0.84 cm yr−1 vs. mean = 0.21 cm yr−1) of the moist soil treatment. The results strongly suggest that the long drainage period in moist soil management limits carbon storage over time. Managers across the National Wildlife Refuge system have an opportunity to increase carbon storage by minimizing drainage in impoundments as much as practicable.

  11. Water-quality study of Tulpehocken Creek, Berks County, Pennsylvania, prior to impoundment of Blue Marsh Lake

    Science.gov (United States)

    Barker, James L.

    1977-01-01

    Blue Marsh Lake is planned as a multipurpose impoundment to be constructed on Tulpehocken Creek near Bernville, Berks County, Pennsylvania. Prior to construction, samples of water, bed material, and soil were collected throughout the impoundment site to determine concentrations of nutrients, insecticides, trace metals, suspended sediment, and bacteria. Analyses of water suggest the Tulpehocken Creek basin to be a highly fertile environment. Nitrogen and phosphorus concentrations near the proposed dam site had median values of 4.5 and 0.13 mg/L, respectively. Suspended sediment discharges average between 100 and 200 tons (90.7 to 181.4 metric tons) per day during normal flows but may exceed 10,000 tons (9,070 metric tons) per day during storm runoff. Highest yields were measured during winter and early spring. Concentrations range from 3 mg/L to more than 500 mg/L. Bed material samples contain trace quantities of aldrin, DDT, DDD, DDE, dieldrin, and chlordane. Polychlorinated biphyenyls (PCB's) ranged from 10 to 100 μg/kg. Soils at the impoundment site are of average fertility. However, the silt loam texture is ideal for attachment and growth of aquatic plants. Bacteria populations indicative of recent fecal contamination are prevalent in the major inflows to the proposed lake. Fecal Coliform exceeded the standards recommended by the Federal Water Pollution Administration Committee on Water Quality Criteria for public water supply in 29 percent of the monthly samples, and exceeded the recommended public bathing waters standard in 83 percent of the samples collected from June to September. Arsenic from an industrial waste was found in the water, suspended sediment, and bed material of Tulpehocken Creek in concentrations of 0 to 30 μg/l, 2 to 879 μg/l, and 1 to 79 μg/g, respectively. It represents a potential environmental hazard; however, the measured concentrations are less than that known to be harmful to man, fish, or wildlife, according to published water

  12. Monticello Mill Tailings Site Operable Unit III Annual Groundwater Report May 2014 Through April 2015, October 2015

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Jason [USDOE Office of Legacy Management, Washington, DC (United States); Smith, Fred [Navarro Research and Engineering, Inc., Oak Ridge, TN (United States)

    2015-10-01

    This report provides the annual analysis of water quality restoration progress, cumulative through April 2015, for Operable Unit (OU) III, surface water and groundwater, of the U.S. Department of Energy (DOE) Office of Legacy Management Monticello Mill Tailings Site (MMTS). The MMTS is a Comprehensive Environmental Response, Compensation, and Liability Act National Priorities List site located in and near the city of Monticello, San Juan County, Utah. MMTS comprises the 110-acre site of a former uranium- and vanadium-ore-processing mill (mill site) and 1,700 acres of surrounding private and municipal property. Milling operations generated 2.5 million cubic yards of waste (tailings) from 1942 to 1960. The tailings were impounded at four locations on the mill site. Inorganic constituents in the tailings drained from the impoundments to contaminate local surface water (Montezuma Creek) and groundwater in the underlying alluvial aquifer. Mill tailings dispersed by wind and water also contaminated properties surrounding and downstream of the mill site. Remedial actions to remove and isolate radiologically contaminated soil, sediment, and debris from the former mill site (OU I) and surrounding properties (OU II) were completed in 1999 with the encapsulation of the wastes in an engineered repository located on DOE property 1 mile south of the former mill site. Contamination of groundwater and surface water remains within OU III at levels that exceed water quality protection standards. Uranium is the primary contaminant of concern. LM implemented monitored natural attenuation with institutional controls as the OU III remedy in 2004. Because groundwater restoration proceeded more slowly than expected and did not meet performance criteria established in the OU III Record of Decision (June 2004), LM implemented a contingency action in 2009 by an Explanation of Significant Difference to include a pump-and-treat system using a single extraction well and treatment by zero

  13. Density Structure of the Martian Tail

    Science.gov (United States)

    Nauth, M.; Fowler, C. M.; Andersson, L.; Pilinski, M.; DiBraccio, G. A.

    2017-12-01

    The lack of a significant, global dipole magnetic field at Mars results in a more comet-­-like interaction between the planet and the solar wind. Subsequently, the tail region is highly dynamic and variable in nature. The majority of plasma in the Martian tail is low density (a few cm-3) and warm (several eV). There are times, however, when magnetic flux tubes connected to the ionosphere are configured such that colder (effects of the local magnetic field orientation on such events.

  14. Dynamics of Histone Tails within Chromatin

    Science.gov (United States)

    Bernier, Morgan; North, Justin; Page, Michael; Jaroniec, Christopher; Hammel, Christopher; Poirier, Michael

    2012-02-01

    Genetic information in humans is encoded within DNA molecules that is wrapped around histone octamer proteins and compacted into a highly conserved structural polymer, chromatin. The physical and material properties of chromatin appear to influence gene expression by altering the accessibility of proteins to the DNA. The tails of the histones are flexible domains that are thought to play a role in regulating DNA accessibility and compaction; however the molecular mechanisms for these phenomena are not understood. I will present CW-EPR studies on site directed spin labeled nucleosomes that probe the structure and dynamics of these histone tails within nucleosomes.

  15. Probabilistic risk assessment for the Sandia National Laboratories Technical Area V Liquid Waste Disposal System surface impoundments

    International Nuclear Information System (INIS)

    Dawson, L.A.; Eidson, A.F.

    1996-01-01

    A probabilistic risk assessment was completed for a former radioactive waste disposal site. The site, two unlined surface impoundment, was designed as part of the Liquid Waste Disposal System (LWDS) to receive radioactive effluent from nuclear reactors in Technical Area-V (TA-V) at Sandia National Laboratories/New Mexico (SNL/NM). First, a statistical comparison of site sampling results to natural background, using EPA methods, and a spatial distribution analysis were performed. Risk assessment was conducted with SNL/NM's Probabilistic Risk Evaluation and Characterization Investigation System model. The risk assessment indicated that contamination from several constituents might have been high enough to require remediation. However, further analysis based on expected site closure activities and recent EPA guidance indicated that No Further Action was acceptable

  16. Uptake of uranium, thorium and radium isotopes by plants growing in dam impoundment Tasotkel and the Lower Shu region (Kazakhstan)

    Energy Technology Data Exchange (ETDEWEB)

    Matveyeva, Ilona; Burkitbayev, Mukhambetkali [al-Farabi Kazakh National University, Almaty (Kazakhstan). Faculty of Chemistry and Chemical Technology; Jacimovic, Radojko [Jozef Stefan Institute, Ljubljana (Slovenia). Dept. of Environmental Sciences; Planinsek, Petra; Smodis, Borut [Jozef Stefan Institute, Ljubljana (Slovenia). Dept. of Environmental Sciences; Jozef Stefan International Postgraduate School, Ljubljana (Slovenia)

    2016-04-01

    The activity concentrations of isotopes of uranium, thorium and radium-226 in dominant species of plants (Xantium strumarium, Phragmites communis, Artemisia nitrosa and Artemisia serotina) growing on the territories contaminated by uranium industry of Kazakhstan (close to dam impoundment Tasotkel and the Lower Shu region) are presented. The obtained data showed the significant variations of activity concentrations of isotopes of uranium, thorium and radium-226 in above ground parts. The concentrations of most of the investigated radionuclides in the root system are higher than in the aboveground parts; it can be explained by root barrier. It was found that the highest root barrier has Xantium strumarium, especially for uranium isotopes. The concentration ratios of radionuclides were calculated, and as the result it was found that the highest accumulation ability in the investigated region has Artemisia serotina.

  17. 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.

  18. Electrokinetic remediation of copper mine tailings

    DEFF Research Database (Denmark)

    Hansen, Henrik K.; Rojo, Adrián; Ottosen, Lisbeth M.

    2007-01-01

    in sulphuric acidified tailings) without bipolar electrodes to 42% when bipolar electrodes were implemented. Furthermore, the results showed that in this system sulphuric acid addition prior to remediation was better than citric acid addition. In addition, applying a too strong electric field (even...

  19. Zone-tailed Hawk (Buteo albonotatus)

    Science.gov (United States)

    Scott H. Stoleson; Giancarlo Sadoti

    2010-01-01

    The Zone-tailed Hawk (Buteo albonotatus) might well be dubbed "the Great Pretender" because it so closely resembles the ubiquitous Turkey Vulture (Cathartes aura) in appearance and behavior as to be frequently mistaken for it. In the border regions where it lives, it may be confused as well with another "Mexican" raptor, the Common Black-Hawk (...

  20. 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.

  1. Aging geomembranes in uranium tailings leachate

    International Nuclear Information System (INIS)

    Mitchell, D.H.

    1984-01-01

    Pacific Northwest Laboratory (PNL) is performing a study to provide the US Nuclear Regulatory Commission (NRC) with a database to support licensing of uranium mill tailings ponds with geomembranes. As part of this study, geomembranes have been aged under conditions closely approximating those of uranium mill tailings ponds with acidic leachate. The aging procedure and results of tests with high density polyethylene (HDPE) and polyvinyl chloride (PVC) are presented. No degradation products were detected in the HDPE or the leachate. We expect that HDPE will not suffer significant chemical attack by uranium tailings and acidic leachate over the active life (20 years or less) of a pond. Because no large changes in physical properties were observed, we expect that changes in the physical properties of HDPE will be minor at mill tailings ponds with acidic leachate. Although testing is still underway, the PVC geomembrane has undergone some chemical reactions. Elongation declined as exposure temperatures increased, while other physical properties remained constant. The amount of aging simulated will be estimated when chemical analyses on PVC samples are completed. 11 references, 3 figures, 4 tables

  2. DNA isolation from rat tail or ear

    NARCIS (Netherlands)

    Cuppen, E.

    2010-01-01

    This protocol describes a rapid procedure for isolating DNA from rat tail or ear punches. The simplest version of the protocol can be scaled for use in 96-well (deep-well) plates. The quality of the DNA is sufficient for any polymerase chain reaction (PCR)-based genotyping approach.

  3. Mechanisms of tail resorption during anuran metamorphosis.

    Science.gov (United States)

    Nakai, Yuya; Nakajima, Keisuke; Yaoita, Yoshio

    2017-09-26

    Amphibian metamorphosis has historically attracted a good deal of scientific attention owing to its dramatic nature and easy observability. However, the genetic mechanisms of amphibian metamorphosis have not been thoroughly examined using modern techniques such as gene cloning, DNA sequencing, polymerase chain reaction or genomic editing. Here, we review the current state of knowledge regarding molecular mechanisms underlying tadpole tail resorption.

  4. Pulse pile-up. II: Tailed pulses

    International Nuclear Information System (INIS)

    Wilkinson, D.H.

    1990-07-01

    The considerations of the preceding paper are extended to the case of pulses having infinite (exponential) tails. Exact solutions are presented for pure exponential pulses all of the same height; ruin theory is applied for pulses of more realistic form. (Author) (2 refs., 9 figs.)

  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. The production and handling of dry uranium and other tailings

    International Nuclear Information System (INIS)

    Robertson, A.M.; van Zyl, D.; Fisher, J.W.

    1982-01-01

    This paper describes equipment for producing dry tailings and proposes a simple test procedure for evaluating the effectiveness with which the resulting sloppy products can be handled in the field. Examples are given of the application of ''dry'' tailings disposal for uranium tailings and for other tailings products in the USA and other countries. The ''sloppy'' nature of ''dry'' tailings often make them difficult to handle in bulk. Methods for assessing handling, transport and stability problems associated with the tailings are discussed. Tailings are considered to be ''dry'' if they have been de-watered sufficiently that they can stand in a substantial pile and can be handled by conventional earth moving equipment without liquefying. It is determined that tailings with moisture contents below or a little above the liquid limit can generally be handled by conventional earth moving equipment. Trafficability and stability require moisture contents appreciably below the liquid limit

  7. 14 CFR 23.745 - Nose/tail wheel steering.

    Science.gov (United States)

    2010-01-01

    ... AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Design and Construction Landing Gear § 23.745 Nose/tail wheel steering. (a) If nose/tail wheel steering is installed, it must be... gear. Floats and Hulls ...

  8. Microorganisms in oil sands tailings ponds influence the properties and behaviour of mature fine tailings

    Energy Technology Data Exchange (ETDEWEB)

    Bressler, D.; Cardenas, M.; Fedorak, P.M.; Guigard, S.; Gupta, R.; Siddique, T.; Foght, J. [Alberta Univ., Edmonton, AB (Canada)

    2010-07-01

    Large numbers of microorganisms are present in the mature fine tailings produced during oil sands operations. Many different types of microbes grow in communities that compete and cooperate. Most of the microorganisms are anaerobic, and include sulfate-reducing bacteria, nitrate-reducing bacteria, iron-reducing bacteria, fermenters, and methanogens. The microbes produce approximately 40 million litres of greenhouse gases (GHGs), methane (CH{sub 4}) and carbon dioxide (CO{sub 2}). All tailings ponds are microbiologically different. The gases are produced by microbial waste products and have been observed to degrade fugitive naphtha in fresh tailings at a Syncrude oil sands facility. At a Shell-Albian Sands facility, the microbes degraded into trisodium citrate. The microbes can aid in the settling of tailings. Agricultural byproducts have been added to tailings in order to demonstrate methane production. However, flow through systems are required to accelerate the biodensification of tailings ponds, and further studies are needed to ensure that the quality of recovered water is maintained for re-use. Various microbe degradation processes and models were presented. tabs., figs.

  9. Strategic Management Plan for Columbian Sharp-Tailed Grouse 2002

    OpenAIRE

    State of Utah, Department of Natural Resoures, Division of Wildlife Resources

    2002-01-01

    The Columbian Sharp-tailed Grouse (Tympanuchus phasianellus columbianus) is one of seven subspecies of Sharp-tailed Grouse. Historically, Columbian Sharp-tailed Grouse occurred within sagebrush-native bunch grass habitat throughout the intermountain region, extending from British Columbia, Washington, Idaho and Montana south through portions of Oregon, California, Nevada, Utah, Wyoming, Colorado and New Mexico. Sharp-tailed Grouse populations range-wide began declining during 1880-1920 (Bart ...

  10. 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.

  11. 14 CFR 25.497 - Tail-wheel yawing.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Tail-wheel yawing. 25.497 Section 25.497... STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Ground Loads § 25.497 Tail-wheel yawing. (a) A vertical ground reaction equal to the static load on the tail wheel, in combination with a side component of equal...

  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. 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 ...

  14. 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.

  15. Mineralogical and geochemical investigation of clay-rich mine tailings from a closed phosphate mine, Bartow Florida, USA

    Science.gov (United States)

    Krekeler, Mark P. S.; Morton, Julie; Lepp, Jill; Tselepis, Cynthia M.; Samsonov, Mikhail; Kearns, Lance E.

    2008-07-01

    Clay-rich mine tailings from phosphate mine operations in Florida are a major environmental and economic problem. Options for reclamation and restoration for these tailings are very limited and are fundamentally restricted by poor physical properties such as low mechanical strength, low hydraulic conductivity, and heavy metal content. The major control on these bulk physical properties is the mineralogy of the materials. Eight continuous push borings were obtained to investigate stratigraphy, mineralogy, aspects of geochemistry, and bulk properties of a deposit of clay-rich mine tailings from a phosphate mine near Bartow, Florida that ceased operations in the early 1970s. Stratigraphy is dominated by laminated clay-rich sediment with minor units of silt and sand. An intact kaolinite liner occurs near the impoundment walls and the impoundment floor has approximately 4 m of relief. Moisture content varies from 4.35 to 57.40 wt% and organic content varies from 0.41 to 9.53 wt%. Bulk XRF investigation indicates that the P2O5 concentrations vary from approximately 4 to 21 wt%. A very strong correlation ( r 2 = 0.92) between CaO and P2O5 indicates that apatite is a major control on the phosphate. The strong correlation ( r 2 = 0.77) of Al2O3 and TiO2 suggests that the source materials for this deposit are comparatively uniform. A number of heavy metal elements and trace elements occur. Cr, V, Ni, Cu are interpreted to be in phosphate minerals, largely apatite. Sr and Pb are interpreted to be in both phyllosilicates and phosphate minerals. Two populations of apatite were observed in the clay-sized fraction, one that was Fe and Si- bearing and another that was only Si-bearing. Fe-bearing apatite had Fe2O3 contents that varied from 0.38 to 5.32 wt% and SiO2 contents that varied from 0.90 to 3.32 wt%. The other apatite population had a wider range of SiO2 contents that varied from 0.77 to 8.80 wt%. TEM imaging shows that apatite grains are dominantly single crystals with

  16. 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 deposited...... less than 2 years ago (new tailings). Parameters analyzed were the applied voltage drop, acid concentration during pretreatment, and the use of either passive or ion exchange membranes in the experimental setup. The comparison of the results confirms that there are differences in the electroremediation...... between the two tailings, even if the pH is similar and a mineralogical analysis showed similarities between the samples with respect to composition. It was found that an electroremediation is more favorable on the old tailings. The results showed that the best experimental conditions for both tailings...

  17. Long-Term Stewardship at a Former Uranium Mill Tailings Site in Riverton, Wyoming WM2017-17090

    Energy Technology Data Exchange (ETDEWEB)

    Dam, William [USDOE Office of Legacy Management, Washington, DC (United States); Gil, Dr. April [USDOE Office of Legacy Management, Washington, DC (United States); Johnson, Raymond H. [Navarro Research and Engineering, Oak Ridge, TN (United States); Campbell, Sam [Navarro Research and Engineering, Oak Ridge, TN (United States)

    2017-03-01

    The US Department of Energy Office of Legacy Management (LM) is responsible for maintaining protective public health and environmental conditions at former uranium mill tailings sites nationwide via long-term stewardship. One of these sites, a former uranium mill near Riverton, Wyoming, is within the boundary of the Wind River Indian Reservation and operated from 1958 to 1963. Tailings and contaminated material associated with mill operations were removed and transported to an offsite disposal cell in 1989. The remedial action was completed under Title I of the Uranium Mill Tailings Radiation Control Act of 1978. Milling operations, which included an unlined tailings impoundment and an unlined evaporation pond, contaminated the shallow groundwater, resulting in a downgradient groundwater plume that discharges to the Little Wind River. A natural flushing compliance strategy was implemented in 1998. This strategy allows contaminants of concern to naturally flush from the groundwater, provided that contaminants flush below US Environmental Protection Agency maximum concentration limits within 100 years. As part of the compliance strategy, LM has implemented a groundwater monitoring program along with institutional controls that include the installation of an alternate water supply, continued sampling of private wells, and restrictions on well drilling and gravel pit construction. LM works closely with local stakeholders and community members to ensure that these institutional controls are in place and maintained. The Riverton site provides an interesting case study where contaminant remobilization due to river flooding prompted a reevaluation of the conceptual site model to verify if the current compliance strategy would remain protective of human health and the environment. Concentrations of groundwater contaminants, which include sulfate, molybdenum, and uranium, were transiently elevated following flooding of the Little Wind River in 2010 and 2016. These flood

  18. Remedial Action Plan and site design for stabilization of the inactive uranium mill tailings site at Gunnison, Colorado. Attachment 5, Supplemental radiological data: Final report

    Energy Technology Data Exchange (ETDEWEB)

    1992-10-01

    Diffusion coefficients for radon gas in earthen materials are required to design suitable radon-barrier covers for uranium tailings impoundments and other materials that emit radon gas. Many early measurements of radon diffusion coefficients relied on the differences in steady-state radon fluxes measured from radon source before and after installation of a cover layer of the material being tested. More recent measurements have utilized the small-sample transient (SST) technique for greater control on moistures and densities of the test soils, greater measurement precision, and reduced testing time and costs. Several of the project sites for the US Department of Energy`s Uranium Mill Tailings Remedial Action (UMTRA) Program contain radiologically contaminated subsurface material composed predominantly of cobbles, gravels andsands. Since remedial action designs require radon diffusion coefficients for the source materials as well as the cover materials, these cobbly and gravelly materials also must be tested. This report contains the following information: a description of the test materials used and the methods developed to conduct the SST radon diffusion measurements on cobbly soils; the protocol for conducting radon diffusion tests oncobbly soils; the results of measurements on the test samples; and modifications to the FITS computer code for analyzing the time-dependent radon diffusion data.

  19. Tail biting behaviour and tail damage in pigs and the relationship with general behaviour: Predicting the inevitable?

    NARCIS (Netherlands)

    Ursinus, W.W.; Reenen, van C.G.; Kemp, B.; Bolhuis, J.E.

    2014-01-01

    Tail biting behaviour in pigs is a common problem in conventional housing systems. Our study examined the consistency over time in tail biting and tail damage and it explored the predictive value of general behaviours observed in individual pigs and in pens as a whole. Pigs (n = 480), reared in

  20. Monte Carlo-Based Tail Exponent Estimator

    Czech Academy of Sciences Publication Activity Database

    Baruník, Jozef; Vácha, Lukáš

    2010-01-01

    Roč. 2010, č. 6 (2010), s. 1-26 R&D Projects: GA ČR GA402/09/0965; GA ČR GD402/09/H045; GA ČR GP402/08/P207 Institutional research plan: CEZ:AV0Z10750506 Keywords : Hill estimator * α-stable distributions * tail exponent estimation Subject RIV: AH - Economics http://library.utia.cas.cz/separaty/2010/E/barunik-0342493.pdf

  1. T-tail flutter analysis using Edge

    CSIR Research Space (South Africa)

    Van Zyl, Lourens H

    2011-11-01

    Full Text Available shape components). The solution of the structural equation of motion was modified accordingly. This approach is obviously very costly in terms of memory, since a modal mesh deformation is associated with each quadratic mode shape component... a permanent disclaimer on our CFD computer room door that reads: ?The purpose of simulation is insight, not numbers.? Oscar Buneman 1986 A more cynical person, e.g. the first author, might have replaced ?insight? with ?colours?. T-tail flutter...

  2. Tail Rotor Airfoils Stabilize Helicopters, Reduce Noise

    Science.gov (United States)

    2010-01-01

    Founded by former Ames Research Center engineer Jim Van Horn, Van Horn Aviation of Tempe, Arizona, built upon a Langley Research Center airfoil design to create a high performance aftermarket tail rotor for the popular Bell 206 helicopter. The highly durable rotor has a lifetime twice that of the original equipment manufacturer blade, reduces noise by 40 percent, and displays enhanced performance at high altitudes. These improvements benefit helicopter performance for law enforcement, military training, wildfire and pipeline patrols, and emergency medical services.

  3. Effects of a drawdown on plant communities in a freshwater impoundment at Lacassine National Wildlife Refuge, Louisiana

    Science.gov (United States)

    Howard, Rebecca J.; Allain, Larry

    2012-01-01

    Disturbance is an important natural process in the creation and maintenance of wetlands. Water depth manipulation and prescribed fire are two types of disturbance commonly used by humans to influence vegetation succession and composition in wetlands with the intention of improving wildlife habitat value. A 6,475-hectare (ha) impoundment was constructed in 1943 on Lacassine National Wildlife Refuge in southwest Louisiana to create freshwater wetlands as wintering waterfowl habitat. Ten years after construction of the impoundment, called Lacassine pool, was completed, refuge staff began expressing concerns about increasing emergent vegetation cover, organic matter accumulation, and decreasing area of open water within the pool. Because the presence of permanent standing water impedes actions that can address these concerns, a small impoundment within the pool where it was possible to manipulate water depth was created. The 283-ha subimpoundment called Unit D was constructed in 1989. Water was pumped from Unit D in 1990, and the unit was permanently reflooded about 3 years later. Four prescribed fires were applied during the drawdown. A study was initiated in 1990 to investigate the effect of the experimental drawdown on vegetation and soils in Unit D. Four plant community types were described, and cores were collected to measure the depth of the soil organic layer. A second study of Unit D was conducted in 1997, 4 years after the unit was reflooded, by using the same plots and similar sampling methods. This report presents an analysis and synthesis of the data from the two studies and provides an evaluation of the impact of the management techniques applied. We found that plant community characteristics often differed among the four communities and varied with time. Species richness increased in two of the communities, and total aboveground biomass increased in all four during the drawdown. These changes, however, did not persist when Unit D was reflooded; by 1997

  4. 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

  5. Change characteristics of DSi and nutrition structure at the Yangtze River Estuary after Three Gorges Project impounding and their ecological effect

    Directory of Open Access Journals (Sweden)

    Li Lei

    2017-06-01

    Full Text Available The variation law of dissolved silica (DSi, dissolved inorganic nitrogen (DIN, dissolved inorganic phosphorus (DIP and nutrition structure after the Three Gorges Project (TGP impounding as well as their ecological effect were analyzed according to monitoring survey of the Yangtze River Estuary in spring (May and summer (August from 2004-2009. The results showed that after impounding, DSi and DIN concentration decreased and increased, respectively. During the study period, DSi decreased by about 63%, while DIN almost tripled. DIP concentration fluctuated slightly. With respect to nutrition structure, N:P increased, whereas Si:P and Si:N declined. According to chemometry standard of nutrient limits, nutrition structure tended to be imbalanced and the limiting factor of phytoplankton growth (P was studied. Changes of nutrition structure have largely decreased diatom and caused different composition of dominant phytoplankton species. This may change ecosystem structure of the Yangtze River Estuary.

  6. 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

  7. Cement mixtures containing copper tailings as an additive: durability properties

    Directory of Open Access Journals (Sweden)

    Obinna Onuaguluchi

    2012-12-01

    Full Text Available The effects of copper tailings as an additive, on some durability properties of cement mixtures were investigated. In each mixture, copper tailings addition levels by mass were 0%, 5% and 10%. Compared to the control samples, copper tailings blended pastes showed superior performance against autoclave expansion while insignificant decreases in sulfate resistance of mortars were observed. Copper tailings increased the water absorption and total permeable voids of concretes slightly. However, the compressive and flexural strengths of blended concretes were higher than those of the control samples. Similarly, improved resistance to acid attack and chloride penetration as the copper tailings content of concretes increased were also observed. Results further showed that the ASTM C 1202 rapid chloride permeability test may not be a valid indicator of chloride migration in mixtures containing conductive copper tailings. These results suggest that copper tailings can potentially enhance the durability properties of cement based materials.

  8. 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.

  9. 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.

  10. 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

  11. Synchronous response of sedimentary organic carbon accumulation on the inner shelf of the East China Sea to the water impoundment of Three Gorges and Gezhouba Dams

    Science.gov (United States)

    Lin, Jia; Zhu, Qing; Hong, Yuehui; Yuan, Lirong; Liu, Jinzhong; Xu, Xiaoming; Wang, Jianghai

    2018-01-01

    Coastal seas, located between continents and the open ocean, are an important active carbon pool. The sedimentary total organic carbon (TOC) in these areas is a mixture of terrestrial and marine sources, and can be a powerful proxy for tracing natural processes and human activities. In this study, one fine-grained sediment core (DH5-1) from the inner shelf of the East China Sea was systematically analyzed for TOC and black carbon (BC) contents and TOC stable carbon isotope ratios (δ13C). By combining these data with 210Pb dating, an improved carbon correction model and a two end-member mixing model, we reconstructed century-scale high-resolution sequences of corrected TOC, terrestrial TOC and marine TOC contents and identified two carbon depletion events in the DH5-1 record. The two events, shown as two minima in the TOC profiles, correspond temporally to 1985-1987 AD and 2003-2006 AD, which exactly matches the water impoundment of the Gezhouba Dam and Three Gorges Dam, respectively. In addition, the variations in TOC contents and δ13C values before, during or after the minima demonstrate a relationship between the depletion events and water impoundment of the dams on the Changjiang River. The TOC reductions may represent synchronous responses of sedimentary TOC and resultant ecological effects on the inner shelf of the East China Sea to the water impoundment of the dams. These new TOC records reflect the interaction between natural and anthropogenic processes and, accordingly, provide a deep insight and important references for assessing marine ecological effects resulting from water impoundment of largescale dams.

  12. Resource use by the facultative lepidophage Roeboides affinis (Günther, 1868: a comparison of size classes, seasons and environment types related to impoundment

    Directory of Open Access Journals (Sweden)

    Miriam P. Albrecht

    Full Text Available We report the consumption of scales and other food resources by the facultative lepidophage Roeboides affinis in the upper Tocantins River where it was impounded by the Serra da Mesa Hydroelectric Dam. We compared the diet among size classes, between dry and wet seasons, and between sites with distinct water flow characteristics (lotic vs. lentic related to the distance from the dam and phase of reservoir development. As transparency and fish abundance increased after impoundment, we expected a higher consumption of scales in lentic sites. Likewise, habitat contraction, higher transparency and decrease in terrestrial resources availability, would promote a higher consumption of scales. Scales were consumed by 92% of individuals and represented 26% of the total volume of resources ingested by R. affinis. Diet composition varied significantly among size classes, with larger individuals consuming more scales and larger items, especially odonatans and ephemeropterans. Scale consumption was not significantly different between dry and wet seasons. Roeboides affinis incorporated some food items into the diet as a response to the impoundment, like other species. Scale consumption was higher in lotic sites, refuting our initial hypothesis, what suggests that the lepidophagous habit is related the rheophilic nature of R. affinis.

  13. Mercury concentrations of fish in Southern Indian Lake and Issett Lake, Manitoba 1975-88: The effect of lake impoundment and Churchill River diversion

    International Nuclear Information System (INIS)

    Strange, N.E.; Bodaly, R.A.; Fudge, R.J.P.

    1991-01-01

    Southern Indian and Issett Lakes in northern Manitoba were flooded in 1976 as part of Manitoba Hydro's Churchill River diversion project. Fish were collected from 1975 to 1988 from five regional sites on the lakes to examine the effects of impoundment and river diversion on muscle mercury concentrations. Raw data for individual fish caught in 1987 and 1988 are presented, along with means and analyses calculated over the entire 1975-1988 study period. Mercury concentrations in whitefish, pike, and walleye increased significantly after impoundment. Whitefish mercury levels peaked in 1978 and have since declined to near pre-flooding levels. Northern pike and walleye mercury levels were much higher than for whitefish. Pike mercury concentrations showed no indication of declining after 12 years of impoundment, but walleye mercury levels at 2 of the 5 Southern Indian Lake sites declined from maximum recorded levels. Significant variability in fish mercury concentrations was noted both from year to year and among the sites. It is suggested that site-to-site variations are due to varying conditions in the reservoir which stimulate mercury methylation. Since there appears to be an ongoing long-term source of mercury and organic material from the eroding shorelines, pike and walleye mercury concentrations are expected to remain high for many years. 25 refs., 7 figs., 20 tabs

  14. Restoring tides to reduce methane emissions in impounded wetlands: A new and potent Blue Carbon climate change intervention

    Science.gov (United States)

    Kroeger, Kevin D.; Crooks, Stephen; Moseman-Valtierra, Serena; Tang, Jianwu

    2017-01-01

    Coastal wetlands are sites of rapid carbon (C) sequestration and contain large soil C stocks. Thus, there is increasing interest in those ecosystems as sites for anthropogenic greenhouse gas emission offset projects (sometimes referred to as “Blue Carbon”), through preservation of existing C stocks or creation of new wetlands to increase future sequestration. Here we show that in the globally-widespread occurrence of diked, impounded, drained and tidally-restricted salt marshes, substantial methane (CH4) and CO2 emission reductions can be achieved through restoration of disconnected saline tidal flows. Modeled climatic forcing indicates that tidal restoration to reduce emissions has a much greater impact per unit area than wetland creation or conservation to enhance sequestration. Given that GHG emissions in tidally-restricted, degraded wetlands are caused by human activity, they are anthropogenic emissions, and reducing them will have an effect on climate that is equivalent to reduced emission of an equal quantity of fossil fuel GHG. Thus, as a landuse-based climate change intervention, reducing CH4 emissions is an entirely distinct concept from biological C sequestration projects to enhance C storage in forest or wetland biomass or soil, and will not suffer from the non-permanence risk that stored C will be returned to the atmosphere.

  15. Restoring tides to reduce methane emissions in impounded wetlands: A new and potent Blue Carbon climate change intervention.

    Science.gov (United States)

    Kroeger, Kevin D; Crooks, Stephen; Moseman-Valtierra, Serena; Tang, Jianwu

    2017-09-20

    Coastal wetlands are sites of rapid carbon (C) sequestration and contain large soil C stocks. Thus, there is increasing interest in those ecosystems as sites for anthropogenic greenhouse gas emission offset projects (sometimes referred to as "Blue Carbon"), through preservation of existing C stocks or creation of new wetlands to increase future sequestration. Here we show that in the globally-widespread occurrence of diked, impounded, drained and tidally-restricted salt marshes, substantial methane (CH 4 ) and CO 2 emission reductions can be achieved through restoration of disconnected saline tidal flows. Modeled climatic forcing indicates that tidal restoration to reduce emissions has a much greater impact per unit area than wetland creation or conservation to enhance sequestration. Given that GHG emissions in tidally-restricted, degraded wetlands are caused by human activity, they are anthropogenic emissions, and reducing them will have an effect on climate that is equivalent to reduced emission of an equal quantity of fossil fuel GHG. Thus, as a landuse-based climate change intervention, reducing CH 4 emissions is an entirely distinct concept from biological C sequestration projects to enhance C storage in forest or wetland biomass or soil, and will not suffer from the non-permanence risk that stored C will be returned to the atmosphere.

  16. 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.

  17. Phytomining for Artisanal Gold Mine Tailings Management

    Directory of Open Access Journals (Sweden)

    Baiq Dewi Krisnayanti

    2016-08-01

    Full Text Available Mine tailings are generally disposed of by artisanal and small scale gold miners in poorly constructed containment areas and this leads to environmental risk. Gold phytomining could be a possible option for tailings management at artisanal and small-scale gold mining (ASGM locations where plants accumulate residual gold in their above ground biomass. The value of metal recovered from plants could offset some of the costs of environmental management. Getting gold into plants has been repeatedly demonstrated by many research groups; however, a simple working technology to get gold out of plants is less well described. A field experiment to assess the relevance of the technology to artisanal miners was conducted in Central Lombok, Indonesia between April and June 2015. Tobacco was planted in cyanidation tailings (1 mg/kg gold and grown for 2.5 months before the entire plot area was irrigated with NaCN to induce metal uptake. Biomass was then harvested (100 kg, air dried, and ashed by miners in equipment currently used to ash activated carbon at the end of a cyanide leach circuit. Borax and silver as a collector metal were added to the tobacco ash and smelted at high temperature to extract metals from the ash. The mass of the final bullion (39 g was greater than the mass of silver used as a collector (31 g, indicating recovery of metals from the biomass through the smelt process. The gold yield of this trial was low (1.2 mg/kg dry weight biomass concentration, indicating that considerable work must still be done to optimise valuable metal recovery by plants at the field scale. However, the described method to process the biomass was technically feasible, and represents a valid technique that artisanal and small-scale gold miners are willing to adopt if the economic case is good.

  18. Dwarf Galaxies Swimming in Tidal Tails

    Science.gov (United States)

    2005-01-01

    This false-color infrared image from NASA's Spitzer Space Telescope shows little 'dwarf galaxies' forming in the 'tails' of two larger galaxies that are colliding together. The big galaxies are at the center of the picture, while the dwarfs can be seen as red dots in the red streamers, or tidal tails. The two blue dots above the big galaxies are stars in the foreground. Galaxy mergers are common occurrences in the universe; for example, our own Milky Way galaxy will eventually smash into the nearby Andromeda galaxy. When two galaxies meet, they tend to rip each other apart, leaving a trail, called a tidal tail, of gas and dust in their wake. It is out of this galactic debris that new dwarf galaxies are born. The new Spitzer picture demonstrates that these particular dwarfs are actively forming stars. The red color indicates the presence of dust produced in star-forming regions, including organic molecules called polycyclic aromatic hydrocarbons. These carbon-containing molecules are also found on Earth, in car exhaust and on burnt toast, among other places. Here, the molecules are being heated up by the young stars, and, as a result, shine in infrared light. This image was taken by the infrared array camera on Spitzer. It is a 4-color composite of infrared light, showing emissions from wavelengths of 3.6 microns (blue), 4.5 microns (green), 5.8 microns (orange), and 8.0 microns (red). Starlight has been subtracted from the orange and red channels in order to enhance the dust features.

  19. Contemporary Pollution Due Old Uranium Tails

    International Nuclear Information System (INIS)

    Hadjamberdiev, I.

    2007-01-01

    The areas of our study are uranium mining areas (with tails and dumps) Min-Kush, Kadji-Sai, Mailuu-Suu. These areas situated in different parts of Tien-Shan region. We study the content (and correlations among): level of uranium in environment, immune function and level, level in human teeth. It has been found: content of uranium in river water under tails about 2,0x10-5 gm/litter, and high level in drinking water too 2,0-4,0. Drying grass and flowers uranium content was 0,04-0,51x10-5 gm/gm, most high content were in Tacniatherum crinitum and Atgilops triuncialis. Lams tissues contain 0,005-2,44 mg/g in Min-Kush, 0,03-0,107, in Mailuu-Suu, and 0,001-0,048 mg/g in Kadji-Sai. Human teeth uranium content (Mailuu-Suu): in milk-teeth 0,481x10-6 gm/gm, in former miners 0,7684x10-6 gm/gm. Inhabitants of the area, which not working in uranium industry have 0,6876x10-6 gm/gm. There was low level of immune function (lymphocytes, IgI globulin, etc) in all three regions (in child, in adults, in uranium-mining worked people). There is no doubt of the positive correlations of uranium pollution of water (by underground infiltration from tails) on one hand and, on the other hand - a) grass, b) lambs body, c) human teeth, d) human immune function. Levels of uranium in teeth strictly depend on time of mining contact. (author)

  20. Monte Carlo-based tail exponent estimator

    Czech Academy of Sciences Publication Activity Database

    Baruník, Jozef; Vácha, Lukáš

    2010-01-01

    Roč. 389, č. 21 (2010), s. 4863-4874 ISSN 0378-4371 R&D Projects: GA ČR GA402/09/0965; GA ČR GD402/09/H045; GA ČR GP402/08/P207 Institutional research plan: CEZ:AV0Z10750506 Keywords : Hill estimator * α-stable distributions * Tail exponent estimation Subject RIV: AH - Economics Impact factor: 1.521, year: 2010 http://library.utia.cas.cz/separaty/2010/E/barunik-0346486.pdf

  1. Framework for T-tail flutter analysis

    CSIR Research Space (South Africa)

    Van Zyl, Lourens H

    2011-06-01

    Full Text Available Calculating unsteady generalized aerodynamic forces for a given Mach number, reduced frequency, steady load distribution and deflected shape The p-k flutter solver was modified to Call the DLM routine once to read the geometry At each speed increment... for that condition can be calculated. The present paper presents a procedure for performing a flutter analysis of a T-tailed aircraft in a given loading condition over a range of speeds. The first step at each speed is the aeroelastic trim analysis. Flutter...

  2. Optimization in the decommissioning of uranium tailings

    International Nuclear Information System (INIS)

    1987-06-01

    This report examines in detail the problem of choosing the optimal decommissioning approach for uranium and mill tailings sites. Various decision methods are discussed and evaluated, and their application in similar decision problems are summarized. This report includes, by means of a demonstration, a step by step guide of how a number of selected techniques can be applied to a decommissioning problem. The strengths and weaknesses of various methods are highlighted. A decision system approach is recommended for its flexibility and incorporation of many of the strengths found in other decision methods

  3. Biogeochemistry of metalliferous mine tailings during phytostabilizatio

    Science.gov (United States)

    Chorover, J.; Root, R. A.; Hammond, C.; Wang, Y.; Maier, R. M.

    2015-12-01

    In the semi-arid southwest US, legacy mine tailings and the associated metal(loid) contaminants, are prone to wind dispersion and water erosion. Without remediation, tailings can remain barren for decades to centuries, providing a point source of toxic contamination. Successful mitigation of toxins (As, Pb) from fugitive dust is often limited to confinement and stabilization. Capping mine tailings with soil or gravel is an accepted, although expensive, strategy to reduce erosion. Revegetation via assisted direct planting (also known as phytostabilization) has the potential to be a cost-effective and self-sustaining alternative "green-technology" to expensive capping. The impact of phytostabilization, and requisite added organic carbon and irrigation on mechanisms of contaminant mobility is being investigated with concurrent highly-instrumented greenhouse mesocosms and in situ field studies using advanced microbiological tools and synchrotron x-ray based molecular probes. Composted treatments initially neutralized the near surface acid tailings (~2 to ~6.5). However, after 9 mo the mesocosms showed a gradual and eventual decrease back to pH 2. The exception was the root zone of Atriplex lentiformis, which buffered the acidic conditions for 12 months. Rhizosphere microbiota experienced a 5-log increase in the compost-amended compared to control greenhouse mesocosms. Weathering of the primary sulfidic mineral assemblage, indicated by the iron and sulfur speciation, was shown to control the mobility, speciation and bioavailability of both As and Pb via sequestration in (meta)stable neoformed jarosite phases as plumbojarosite and As(V) substituted for sulfate in hydronium jarosite, with important implications for human and environmental health risk management. We conclude that the disequilibrium imposed by phytostabilization results in an increase of heterotrophic biomass that is concurrent with a time series of geochemical transformations, which controls the species

  4. 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.

  5. On the importance of tail ratios for psychological science.

    Science.gov (United States)

    Voracek, Martin; Mohr, Elisabeth; Hagmann, Michael

    2013-06-01

    Even small group-mean differences (whether combined with variance differences or not) or variance differences alone (absent mean differences) can generate marked and sometimes surprising imbalances in the representation of the respective groups compared in the distributional tail regions. Such imbalances in group representation, quantified as tail ratios, have general importance in the context of any threshold, susceptibility, diathesis-stress, selection, or similar models (including the study of sex differences), as widely conceptualized and applied in the psychological, social, medical, and biological sciences. However, commonly used effect-size measures, such as Cohen's d, largely exploit data information around the center of distributions, rather than from the tails, thereby missing potentially important patterns found in the tail regions. This account reviews the background and history of tail ratios, emphasizes their importance for psychological research, proposes a consensus approach for defining and interpreting them, introduces a tail-ratio calculator, and outlines future research agenda.

  6. 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...

  7. 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

  8. Sulfur biogeochemistry of oil sands composite tailings

    Energy Technology Data Exchange (ETDEWEB)

    Warren, Lesley; Stephenson, Kate [Earth Sciences, McMaster University (Canada)], email: warrenl@mcmaster.ca; Penner, Tara [Syncrude Environmental Research (Canada)

    2011-07-01

    This paper discusses the sulfur biogeochemistry of oil sands composite tailings (CT). The Government of Alberta is accelerating reclamation activities on composite tailings. As a CT pilot reclamation operation, Syncrude is currently constructing the first freshwater fen. Minor unpredicted incidents with H2S gas released from the dewatering process associated with these reclamations have been reported. The objective of this study is to ascertain the connection between microbial activity and H2S generation within CT and to assess the sulfur biogeochemistry of untreated and treated (fen) CT over seasonal and annual timescales. The microbial geochemical interactions taking place are shown using a flow chart. CT is composed of gypsum, sand, clay and organics like naphthenic acids and bitumen. Sulfur and Fe cycling in mining systems and their microbial activities are presented. The chemistry and the processes involved within CT are also given along with the results. It can be said that the diverse Fe and S metabolizing microorganisms confirm the ecology involved in H2S dynamics.

  9. Environmental impact analysis of mine tailing reservoir

    Science.gov (United States)

    Gong, J. Z.

    2016-08-01

    Under certain conditions landscape topography which utilizes mine tailing reservoir construction using is likely to increase lateral recharge source regions, resulting in dramatic changes to the local hydrological dynamic field and recharge of downstream areas initiated by runoff, excretion state, elevated groundwater depth, shallow groundwater, rainfall direct communication, and thinning of the vadose zone. Corrosive leaching of topsoil over many years of exposure to chemical fertilizers and pesticides may result in their dissolution into the groundwater system, which may lead to excessive amounts of many harmful chemicals, therby affecting the physical and mental health of human residents and increase environmental vulnerability and risk associated with the water and soil. According to field survey data from Yujiakan, Qian'an City, and Hebei provinces, this paper analyzes the hydrogeological environmental mechanisms of areas adjacent to mine tailing reservoirs and establishes a conceptual model of the local groundwater system and the concentration-response function between NO3 - content in groundwater and the incidence of cancer in local residents.

  10. Vertical-Tail Aerodynamic Configuration of Space Shuttle Orbiter

    Science.gov (United States)

    1993-07-16

    effect of a rapid drop in aerodynamic efficiency of the vertical tail. Fig. 6. Scheme of a hypersonic Fig. 7. British Hotal scheme research craft KEY: a...5 - SSTO in the absence of vertical tail 6 - U.S. Space Shuttle In the British Hotal scheme (Fig. 7) the anomalous central single vertical tail...Feiji Sheji [Aircraft Design], National Defense Industry Publishing House, 1987, pp. 227-235. 2 Young J C, Underwood J M. e: at. NASA CP-2283, 1983

  11. Approximate MAP Decoding on Tail-Biting Trellises

    OpenAIRE

    Madhu, A. S.; Shankar, Priti

    2005-01-01

    We propose two approximate algorithms for MAP decoding on tail-biting trellises. The algorithms work on a subset of nodes of the tail-biting trellis, judiciously selected. We report the results of simulations on an AWGN channel using the approximate algorithms on tail-biting trellises for the $(24,12)$ Extended Golay Code and a rate 1/2 convolutional code with memory 6.

  12. 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

  13. 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.

  14. 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.

  15. 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.

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

    Science.gov (United States)

    Segev, Ori; Polevikove, Antonina; Blank, Lior; Goedbloed, Daniel; Küpfer, Eliane; Gershberg, Anna; Koplovich, Avi; Blaustein, Leon

    2015-01-01

    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.

  18. 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....

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

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, B.; Lin, X. B.; Kong, X. [Center for Astrophysics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Sun, M. [Department of Physics, University of Alabama in Huntsville, Huntsville, AL 35899 (United States); Ji, L. [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing, Jiangsu 210008 (China); Sarazin, C. [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904-4325 (United States); Nulsen, P. E. J.; Forman, W.; Jones, C. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Roediger, E. [Germany Hamburger Sternwarte, Universität Hamburg, Gojensbergsweg 112, D-21029 Hamburg (Germany); Donahue, M.; Voit, G. M., E-mail: xkong@ustc.edu.cn, E-mail: mingsun.cluster@gmail.com [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States)

    2013-11-10

    We present the analysis of a deep Chandra observation of a ∼2 L{sub *} 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

  20. 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

  1. Electrokinetic remediation of copper mine tailings

    DEFF Research Database (Denmark)

    Hansen, Henrik K.; Rojo, Adrián; Ottosen, Lisbeth M.

    2007-01-01

    in similar experiments but without the bipolar electrodes. The new electrokinetic remediation design was tested on copper mine tailings with different applied electric fields, remediation times and pre-treatment. The results showed that the copper removal was increased from 8% (applying 20V for 8 days......Important process parameters to optimize in electrokinetic soil remediation are those influencing remediation time and power consumption since these directly affect the cost of a remediation action. This work shows how the electrokinetic remediation (EKR) process could be improved by implementing...... bipolar electrodes in the porous material. The bipolar electrodes in EKR meant two improvements: (1) a shorter migration pathway for the contaminant, and (2) an increased electrical conductivity in the remediation system. All together the remediation proceeded faster with lower electrical resistance than...

  2. Hollywood blockbusters and long-tailed distributions

    Science.gov (United States)

    Sinha, S.; Raghavendra, S.

    2004-11-01

    Numerical data for all movies released in theaters in the USA during the period 1997-2003 are examined for the distribution of their popularity in terms of (i) the number of weeks they spent in the Top 60 according to the weekend earnings, and (ii) the box-office gross during the opening week, as well as, the total duration for which they were shown in theaters. These distributions show long tails where the most popular movies are located. Like the study of Redner [S. Redner, Eur. Phys. J. B 4, 131 (1998)] on the distribution of citations to individual papers, our results appear to be consistent with a power-law dependence of the rank distribution of gross revenues for the most popular movies with a exponent close to -1/2.

  3. The cost of decommissioning uranium mill tailings

    International Nuclear Information System (INIS)

    Lush, D.L.; Lendrum, C.; Hostovsky, C.; Eedy, W.; Ashbrook, A.

    1986-04-01

    This report identifies several key operations that are commonly carried out during decommissioning of tailings areas in the Canadian environment. These operations are unit costed for a generic site to provide a base reference case. The unit costs have also been scaled to the quantities required for the decommissioning of four Canadian sites and these scaled quantities compared with site-specific engineering cost estimates and actual costs incurred in carrying out the decommissioning activities. Variances in costing are discussed. The report also recommends a generic monitoring regime upon which both short- and longer-term environmental monitoring costs are calculated. Although every site must be addressed as a site-specific case, and monitoring programs must be tailored to fit a specific site, it would appear that for the conventional decommissioning and monitoring practices that have been employed to date, costs can be reasonably estimated when site-specific conditions are taken into account

  4. Studies on Arsenic Release and its Mitigation from Tailings Dam ...

    African Journals Online (AJOL)

    Studies on Arsenic Release and its Mitigation from Tailings Dam Using Nanomagnetite Particles. ... Ghana Mining Journal ... Abstract. Knowledge of the geochemistry of As in tailings material after beneficiation of gold-bearing sulphidic ores is necessary to comprehend the nature, stability and mobilization of As into the ...

  5. Mineralogy of Tailings Dump around Selebi Phikwe Nickel-Copper ...

    African Journals Online (AJOL)

    This study aimed at mineralogically characterizing the tailings dump emanating from the mining and smelting of nickel-copper (Ni-Cu) at Selebi Phikwe, Botswana, Southern Africa. Samples of tailings dump around the Selebi Phikwe Ni-Cu plant were studied using petrographic microscopy and X-ray Powder Diffraction ...

  6. 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.

  7. Lifshitz Tails for the Interband Light Absorption Coefficient

    Indian Academy of Sciences (India)

    In this paper we consider the interband light absorption coefficient (ILAC) for various models. We show that at the lower and upper edges of the spectrum the Lifshitz tails behaviour of the density of states implies similar behaviour for the ILAC at appropriate energies. The Lifshitz tails property is also exhibited at some points ...

  8. 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

  9. Economic Mineral Potentials Of Tailing Dumps From Alluvial Mining ...

    African Journals Online (AJOL)

    Several tonnes of mine tailing dumps abound in the alluvial tin mining areas of the Jos Plateau. These tailings are considered low in contents of cassiterite, columbite, tantalite, zircon and other minerals normally won from tin mining. Four of these dumps in four different mines located in Barkin Ladi (BL), Gurum (GM), Sabon ...

  10. Uranium mill tailings regulation and the generic environmental impact statement

    International Nuclear Information System (INIS)

    Rogers, V.C.

    1980-01-01

    The following topics are discussed: the history of the Canadian uranium industry; the Canadian management of uranium mining wastes; Canadian federal and provincial effluent guidelines for radium-226; tailings and mine water management; backfill; liquid effluents from tailings storage; barium chloride treatment; mine water (Fay Mine); mine water (Dubyna Mine); and revegetation. 22 refs

  11. Risk factors for canine tail chasing behaviour in Japan.

    Science.gov (United States)

    Goto, Akiko; Arata, Sayaka; Kiyokawa, Yasushi; Takeuchi, Yukari; Mori, Yuji

    2012-06-01

    The aim of this study was to investigate the risk factors for tail chasing behaviour that occurs when a dog spins in tight circles to chase its tail, sometimes biting it. The behaviour is a sign of canine compulsive disorder (CD). A questionnaire about tail chasing behaviour and general information about the animals was used to collect data on seven breeds of pet dogs. The data were gathered at a dog event and at veterinary practices. To determine which variables were associated with tail chasing behaviour, stepwise multiple regression analyses were performed. Regardless of cohort, 'breed' and 'source of acquisition' were significantly associated with tail chasing behaviour. Using a chi-square test, the association between 'source of acquisition' and the behaviour was examined separately in two breeds (Shiba inu and Dachshund) that had the largest number of individuals chasing their tails accompanied by biting and/or growling at them. This factor showed a significant and consistent association across the two breeds. With respect to the risk factors of 'breed' and 'source of acquisition', high percentages of Shiba inu and dogs originating from pet stores were included in the group chasing their tails with biting and/or growling. The results suggest that distinct risk factors exist for tail chasing behaviour and such factors appear to be regulated by both genetics and the environment. Copyright © 2011 Elsevier Ltd. All rights reserved.

  12. Human born with a tail: A case report

    African Journals Online (AJOL)

    Histopathological examination revealed that the tail-like structure contained skin, muscle and adipose tissue only. e infant recovered uneventfully and no neurological de cit was evident on follow-up until 12 months of age. Fig. 1. e dorsal tail. Fig. 2. Magnetic resonance imaging scan showing spina bifida in the lumbosacral.

  13. Tail index and quantile estimation with very high frequency data

    NARCIS (Netherlands)

    J. Daníelsson (Jón); C.G. de Vries (Casper)

    1997-01-01

    textabstractA precise estimation of the tail shape of forex returns is of critical importance for proper risk assessment. We improve upon the efficiency of conventional estimators that rely on a first order expansion of the tail shape, by using the second order expansion. Here we advocate a moments

  14. Assessment of Pollution Potential of Cyanide-Bearing Tailings Dam ...

    African Journals Online (AJOL)

    This study ascertained the types of chemical species that are formed in tailings material of gold leaching plants and assessed their short and long term pollution potential capabilities. The results revealed that chemical, biochemical and geochemical reactions were occurring in the tailings material; producing complexed ...

  15. Probing the density tail of radioactive nuclei with antiprotons

    CERN Document Server

    Obertelli, Alexandre; Uesaka, Tomohiro; Corsi, Anna; Pollacco, Emmanuel; Flavigny, Freddy

    2017-01-01

    We propose an experiment to determine the proton and neutron content of the radial density tail in short-lived nuclei. The objectives are to (i) to evidence new proton and neutron halos, (ii) to understand the development of neutron skins in medium-mass nuclei, (iii) to provide a new observable that characterises the density tail of short-lived nuclei.

  16. Characterisation of gold tailings dams of the Witwatersrand Basin ...

    African Journals Online (AJOL)

    2006-10-04

    Oct 4, 2006 ... bentonite layer between the 9th and 10th meter level to minimise vertical air flow from the bottom of the tailings dams. ... m depth with bentonite. Due to the age of the dams, and the fact that they ...... from Cyanide-Rich Gold Mine. Tailings. Unpublished M.Sc. Thesis, The University of New Bruns- wick, USA.

  17. Black-tailed prairie dog status and future conservation planning

    Science.gov (United States)

    Daniel W. Mulhern; Craig J. Knowles

    1997-01-01

    The black-tailed prairie dog is one of five prairie dog species estimated to have once occupied up to 100 million ha or more in North America. The area occupied by black-tailed prairie dogs has declined to approximately 2% of its former range. Conversion of habitat to other land uses and widespread prairie dog eradication efforts combined with sylvatic plague,

  18. Trace elements contamination of soils around gold mine tailings ...

    African Journals Online (AJOL)

    This study investigated the issue of tailings dams as a potential source of trace elements contamination in soils at the Obuasi gold mine in Ghana. Soil samples taken from depths of up to 12 cm and within a radius of 400 m from the tailings dams (active and recommissioned), were analysed for As, Cu, Pb and. Zn using ...

  19. Individual piglets' contribution to the development of tail biting

    NARCIS (Netherlands)

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

    2011-01-01

    Conflicting hypotheses exist about the contribution of individual pigs to the development of a tail-biting outbreak, but there is limited quantitative information to support or dismiss them. This study aims to quantify the development of tail-biting behaviour at pen and individual piglet level,

  20. Non-equilibrium and band tailing in organic conductors

    Indian Academy of Sciences (India)

    The concept of band tailing with focal point and width of the tail from IR absorption spectra of different organic conductors is found valid even for thermal and elastic changes. The experimental situations like change of solvents, method of preparation, applied pressure and pressure cycle apart from compositions is analyzed ...

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

    African Journals Online (AJOL)

    Tailings deposits from gold and uranium (U) mining in the Witwatersrand basin often contain elevated levels of radioactive and chemo-toxic heavy metals. Through seepage, dissolved U and other metals migrate from tailings deposits via groundwater into adjacent fluvial systems. The subsequent transport through flowing ...

  2. 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 been found to migrate via seepage and groundwater ... Due to elevated concentrations of U and other heavy metals in tailings deposits ... dissolved metals migrate into the underlying groundwater and eventually seep ...

  3. A COUNTER-CURRENT HEAT EXCHANGE SYSTEM IN THE TAIL ...

    African Journals Online (AJOL)

    Under such conditions the arterial blood supplying the tail skin is several degrees cooler than the core temperature ... A thermoregulatory function for the vervet monkey tail has been suggested from observa- tions on the ..... Considering the relative thickness of the human fore-arm and vervet caudal arteries at the respective ...

  4. 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.

  5. 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.

  6. 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...

  7. 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

  8. Jump Tails, Extreme Dependencies, and the Distribution of Stock Returns

    DEFF Research Database (Denmark)

    Bollerslev, Tim; Todorov, Viktor

    We provide a new framework for estimating the systematic and idiosyncratic jump tail risks in financial asset prices. The theory underlying our estimates are based on in-fill asymptotic arguments for directly identifying the systematic and idiosyncratic jumps, together with conventional long......-span asymptotics and Extreme Value Theory (EVT) approximations for consistently estimating the tail decay parameters and asymptotic tail dependencies. On implementing the new estimation procedures with a panel of highfrequency intraday prices for a large cross-section of individual stocks and the aggregate S&P 500...... market portfolio, we find that the distributions of the systematic and idiosyncratic jumps are both generally heavy-tailed and not necessarily symmetric. Our estimates also point to the existence of strong dependencies between the market-wide jumps and the corresponding systematic jump tails for all...

  9. 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.

  10. Diagnostic analysis of electrodialysis in mine tailing materials

    DEFF Research Database (Denmark)

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

    2007-01-01

    types of extracting solutions, such as distilled water, or H2SO4 at pH 0, H2SO4 + HNO3 at pH 1.9 and 4.2 or NH4Cl, in the electrodialytic cell, was investigated. From all the experiments, H2O presented the best performance for the electro-removal of Cu from the old deposited mine tailings, achieving 63......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...... removal results of a soil sampled close to an abandoned cupric pyrite mine-mainly polluted with lead (around 3800ppm) are also presented. The results show that the heavy metals could be mobilized in all three contaminated solid materials using the electrodialytic process. The effect of adding different...

  11. Assessment of heavy metal mobility in mine tailings in the province of Huelva; Evaluacion de la movilidad de metales pesados en residuos mineros de flotacion de mineria metalica en la provincia de Huelva

    Energy Technology Data Exchange (ETDEWEB)

    Arranz Gonzalez, J. C.; Cala Rivero, V.

    2011-07-01

    Metallurgic mine wastes often contain high concentrations of potentially toxic elements, the mobility of which may pose an environmental hazard for water and surrounding ecosystems. We have examined the mobility of Ag, As, Cu, Pb and Zn from composite surface samples (0-20 cm) of different pyritic tailings impoundments in the province of Huelva (Spain). These samples were also subject to physical chemical and mineralogical (XRD) characterization. The total metal content of the tailings ranged between 1.89-11.2 ppm for Ag, 72-610 ppm for As, 245-1194 ppm for Cu, 220-11933 for Pb and 41-706 for Zn, all proving to be highly acidic. The mobility of these elements was assessed by using a seven-step sequential extraction procedure and applying the toxicity characteristic leaching procedure (TCLP). We investigated the applicability of TCLP to the tailings by comparing the results with those of the first steps of the sequential extraction procedure. It was found that the pH values remained buffered (close to 4.97) upon adding the TCLP extraction reagent and that the pH values differed significantly from those of the aqueous extracts. This could result in an underestimation of mobile forms compared with those dissolved in water. We may also conclude that due to the presence of specific minerals or to the preference of some elements for acetate ions the results of any assessment of metal mobility in pyritic tailings using the TCLP test may be questionable. (Author) 42 refs.

  12. 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 biting in tails of

  13. Speciation and characterization of arsenic in gold ores and cyanidation tailings using X-ray absorption spectroscopy

    Science.gov (United States)

    Paktunc, D.; Foster, A.; Heald, S.; Laflamme, G.

    2004-01-01

    . Correlation of Ca with As in iron (III) oxyhydroxides as determined by electron microprobe analysis supports the coprecipitate origin for the presence of Ca in iron (III) oxyhydroxides. The samples containing higher abundances of ferric arsenates released higher As concentrations during the cyanidation tests. The presence of highly soluble ferric arsenates and Ca-Fe arsenates, and relatively unstable iron (III) oxyhydroxides with Fe/As molar ratios of less than 4 in the ore and process tailings suggests that not only the tailings in the impoundment will continue to release As, but also there is the potential for mobilization of As from the natural sources such as the unmined ore. ?? 2004 Elsevier Ltd.

  14. Behavioural and Brain Gene Expression Profiling in Pigs during Tail Biting Outbreaks - Evidence of a Tail Biting Resistant Phenotype.

    Science.gov (United States)

    Brunberg, Emma; Jensen, Per; Isaksson, Anders; Keeling, Linda J

    2013-01-01

    Abnormal tail biting behaviour is a major welfare problem for pigs receiving the behaviour, as well as an indication of decreased welfare in the pigs performing it. However, not all pigs in a pen perform or receive tail biting behaviour and it has recently been shown that these 'neutral' pigs not only differ in their behaviour, but also in their gene expression compared to performers and receivers of tail biting in the same pen. To investigate whether this difference was linked to the cause or a consequence of them not being involved in the outbreak of tail biting, behaviour and brain gene expression was compared with 'control' pigs housed in pens with no tail biting. It was shown that the pigs housed in control pens performed a wider variety of pig-directed abnormal behaviour (belly nosing 0.95±1.59, tail in mouth 0.31±0.60 and 'other' abnormal 1.53±4.26; mean±S.D) compared to the neutral pigs (belly nosing 0.30±0.62, tail in mouth 0.13±0.50 and "other" abnormal 0.42±1.06). With Affymetrix gene expression arrays, 107 transcripts were identified as differently expressed (pbiting in the same pen in an earlier study. Hence, the different expression of these genes cannot be a consequence of the neutral pigs not being involved in tail biting behaviour, but rather linked to the cause contributing to why they were not involved in tail biting interactions. These neutral pigs seem to have a genetic and behavioural profile that somehow contributes to them being resistant to performing or receiving pig-directed abnormal behaviour, such as tail biting, even when housed in an environment that elicits that behaviour in other pigs.

  15. Behavioural and Brain Gene Expression Profiling in Pigs during Tail Biting Outbreaks – Evidence of a Tail Biting Resistant Phenotype

    Science.gov (United States)

    Brunberg, Emma; Jensen, Per; Isaksson, Anders; Keeling, Linda J.

    2013-01-01

    Abnormal tail biting behaviour is a major welfare problem for pigs receiving the behaviour, as well as an indication of decreased welfare in the pigs performing it. However, not all pigs in a pen perform or receive tail biting behaviour and it has recently been shown that these ‘neutral’ pigs not only differ in their behaviour, but also in their gene expression compared to performers and receivers of tail biting in the same pen. To investigate whether this difference was linked to the cause or a consequence of them not being involved in the outbreak of tail biting, behaviour and brain gene expression was compared with ‘control’ pigs housed in pens with no tail biting. It was shown that the pigs housed in control pens performed a wider variety of pig-directed abnormal behaviour (belly nosing 0.95±1.59, tail in mouth 0.31±0.60 and ‘other‘ abnormal 1.53±4.26; mean±S.D) compared to the neutral pigs (belly nosing 0.30±0.62, tail in mouth 0.13±0.50 and “other“ abnormal 0.42±1.06). With Affymetrix gene expression arrays, 107 transcripts were identified as differently expressed (pbiting in the same pen in an earlier study. Hence, the different expression of these genes cannot be a consequence of the neutral pigs not being involved in tail biting behaviour, but rather linked to the cause contributing to why they were not involved in tail biting interactions. These neutral pigs seem to have a genetic and behavioural profile that somehow contributes to them being resistant to performing or receiving pig-directed abnormal behaviour, such as tail biting, even when housed in an environment that elicits that behaviour in other pigs. PMID:23824700

  16. 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.

  17. 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.

  18. 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

  19. 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.

  20. 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.

  1. Tail Risk Constraints and Maximum Entropy

    Directory of Open Access Journals (Sweden)

    Donald Geman

    2015-06-01

    Full Text Available Portfolio selection in the financial literature has essentially been analyzed under two central assumptions: full knowledge of the joint probability distribution of the returns of the securities that will comprise the target portfolio; and investors’ preferences are expressed through a utility function. In the real world, operators build portfolios under risk constraints which are expressed both by their clients and regulators and which bear on the maximal loss that may be generated over a given time period at a given confidence level (the so-called Value at Risk of the position. Interestingly, in the finance literature, a serious discussion of how much or little is known from a probabilistic standpoint about the multi-dimensional density of the assets’ returns seems to be of limited relevance. Our approach in contrast is to highlight these issues and then adopt throughout a framework of entropy maximization to represent the real world ignorance of the “true” probability distributions, both univariate and multivariate, of traded securities’ returns. In this setting, we identify the optimal portfolio under a number of downside risk constraints. Two interesting results are exhibited: (i the left- tail constraints are sufficiently powerful to override all other considerations in the conventional theory; (ii the “barbell portfolio” (maximal certainty/ low risk in one set of holdings, maximal uncertainty in another, which is quite familiar to traders, naturally emerges in our construction.

  2. Making a Magnetorheological Fluid from Mining Tailings

    Science.gov (United States)

    Quitian, G.; Saldarriaga, W.; Rojas, N.

    2017-12-01

    We have obtained magnetite mining tailings and used it to fabricate a magnetorheological fluid (MRF). Mineralogical and morphological characteristics were determined using X-ray diffraction (XRD) and energy dispersive spectrometry (EDS), as well as size and geometry for the obtained magnetite. Finally, the fabricated MRF was rheologically characterized in a device attached to a rheometer. The application of a magnetic field of 0.12 Tesla can increase the viscosity of the MRF by more than 400 pct. A structural formation should occur within the fluid by a reordering of particles into magnetic columns, which are perpendicular to the flow direction. These structures give the fluid an increased viscosity. As the magnetic field increases, the structure formed is more resistant, resulting in an increased viscosity. One can appreciate that with a value equal to or less than 0.06 Tesla of applied magnetic field, many viscosity values associated with the work area of the oils can be achieved (0.025 and 0.34 Pa s).

  3. Flocculation of flotation tailings using thermosensitive polymers

    Directory of Open Access Journals (Sweden)

    Bogacz Wojciech

    2017-09-01

    Full Text Available The key feature of thermosensitive polymers is the reversible transition between the hydrophilic and hydrophopic forms depending on the temperature. Although the main research efforts are focused on their application in different kinds of drug delivery systems, this phenomenon also allows one to precisely control the stability of solid-liquid dispersions. In this paper research on the application of poly(N-isopropylacrylamide copolymers in processing of minerals is presented. In the experiments tailings from flotation plant of one of the coal mines of Jastrzębska Spółka Węglowa S.A. (Poland were used. A laser particle sizer Fritsch Analysette 22 was used in order to determine the Particle Size Distribution (PSD. It was proved that there are some substantial issues associated with the application of thermosensitive polymers in industrial practice which may exclude them from the common application. High salinity of suspension altered the value of Lower Critical Solution Temperature (LCST. Moreover, the co-polymers used in research proved to be efficient flocculating agents without any temperature rise. Finally, the dosage needed to achieve steric stabilization of suspension was greatly beyond economic justification.

  4. 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

  5. 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

  6. 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-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....

  7. Heavy-tailed distributions and robustness in economics and finance

    CERN Document Server

    Ibragimov, Marat; Walden, Johan

    2015-01-01

    This book focuses on general frameworks for modeling heavy-tailed distributions in economics, finance, econometrics, statistics, risk management and insurance. A central theme is that of (non-)robustness, i.e., the fact that the presence of heavy tails can either reinforce or reverse the implications of a number of models in these fields, depending on the degree of heavy-tailedness. These results motivate the development and applications of robust inference approaches under heavy tails, heterogeneity and dependence in observations. Several recently developed robust inference approaches are discussed and illustrated, together with applications.

  8. 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

  9. Automated classification of tailed bacteriophages according to their neck organization.

    Science.gov (United States)

    Lopes, Anne; Tavares, Paulo; Petit, Marie-Agnès; Guérois, Raphaël; Zinn-Justin, Sophie

    2014-11-27

    The genetic diversity observed among bacteriophages remains a major obstacle for the identification of homologs and the comparison of their functional modules. In the structural module, although several classes of homologous proteins contributing to the head and tail structure can be detected, proteins of the head-to-tail connection (or neck) are generally more divergent. Yet, molecular analyses of a few tailed phages belonging to different morphological classes suggested that only a limited number of structural solutions are used in order to produce a functional virion. To challenge this hypothesis and analyze proteins diversity at the virion neck, we developed a specific computational strategy to cope with sequence divergence in phage proteins. We searched for homologs of a set of proteins encoded in the structural module using a phage learning database. We show that using a combination of iterative profile-profile comparison and gene context analyses, we can identify a set of head, neck and tail proteins in most tailed bacteriophages of our database. Classification of phages based on neck protein sequences delineates 4 Types corresponding to known morphological subfamilies. Further analysis of the most abundant Type 1 yields 10 Clusters characterized by consistent sets of head, neck and tail proteins. We developed Virfam, a webserver that automatically identifies proteins of the phage head-neck-tail module and assign phages to the most closely related cluster of phages. This server was tested against 624 new phages from the NCBI database. 93% of the tailed and unclassified phages could be assigned to our head-neck-tail based categories, thus highlighting the large representativeness of the identified virion architectures. Types and Clusters delineate consistent subgroups of Caudovirales, which correlate with several virion properties. Our method and webserver have the capacity to automatically classify most tailed phages, detect their structural module, assign a

  10. An Analysis of a Heuristic Procedure to Evaluate Tail (independence

    Directory of Open Access Journals (Sweden)

    Marta Ferreira

    2014-01-01

    Full Text Available Measuring tail dependence is an important issue in many applied sciences in order to quantify the risk of simultaneous extreme events. A usual measure is given by the tail dependence coefficient. The characteristics of events behave quite differently as these become more extreme, whereas we are in the class of asymptotic dependence or in the class of asymptotic independence. The literature has emphasized the asymptotic dependent class but wrongly infers that tail dependence will result in the overestimation of extreme value dependence and consequently of the risk. In this paper we analyze this issue through simulation based on a heuristic procedure.

  11. 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

  12. 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

  13. Probabilistic calculation of dose commitment from uranium mill tailings

    International Nuclear Information System (INIS)

    1983-10-01

    The report discusses in a general way considerations of uncertainty in relation to probabilistic modelling. An example of a probabilistic calculation applied to the behaviour of uranium mill tailings is given

  14. 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

  15. Practical considerations of pyrite oxidation control in uranium tailings

    International Nuclear Information System (INIS)

    1984-05-01

    The problems posed by the oxidation of pyrite in uranium tailings include the generation of sulfuric acid and acid sulfate metal salts. These have substantial negative impacts on watercourse biota by themselves, and the lowered pH levels tend to mobilize heavy metals present in the tailings the rate of oxidation of pyrite at lower pH levels is catalyzed by sulfur and iron oxidizing bacteria present in soils. No single clear solution to the problems came from this study. Exclusion of air is a most important preventative of bacterial catalysis of oxidation. Bactericides, chemically breaking the chain of integrated oxidation reactions, maintaining anaerobic conditions, or maintaining a neutral or alkaline pH all reduce the oxidation rate. Removal of pyrite by flotation will reduce but not eliminate the impact of pyrite oxidation. Controlled oxidation of the remaining sulfide in the flotation tails would provide an innocuous tailing so far as acidity generation is concerned

  16. Western Red-tailed Skink Distribution in Southern Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Hall, D. B. and Gergor, P. D.

    2011-11-01

    This slide show reports a study to: determine Western Red-tailed Skink (WRTS) distribution on Nevada National Security Site (NNSS); identify habitat where WRTS occur; learn more about WRTS natural history; and document distribution of other species.

  17. Recovery of 'Nsutite' from Tailings Material of Ghana Manganese ...

    African Journals Online (AJOL)

    GMC) Limited Mine, Nsuta. M Ali, RK Amankwah. Abstract. An investigation was conducted for the enrichment of manganese oxide tailings generated by a spiral concentration plant at Ghana Manganese Company (GMC) Limited, Nsuta. The work ...

  18. Biodegradation of cycloalkane carboxylic acids in oil sand tailings

    Energy Technology Data Exchange (ETDEWEB)

    Herman, D.C.; Costerton, J.W. (Calgary Univ., Dept. of Biological Sciences, AB (Canada)); Fedorak, P.M. (Alberta Univ., Dept. of Microbiology, AB (Canada))

    1993-01-01

    The biodegradation of both an n-alkane and several carboxylated cycloalkanes was examined experimentally within tailings produced by the extraction of bitumen from the Athabasca oil sands. The carboxylated cycloalkanes examined were structurally similar to naphthenic acids that have been associated with the acute toxicity of oil sand tailings. The biodegradation potential of naphthenic acids was estimated by determining the biodegradation of both the carboxylated cycloalkanes and hexadecane in oil sand tailings. Carboxylated cycloalkanes were biodegraded within oil sands tailings, although compounds with methyl substitutions on the cycloalkane ring were more resistant to microbial degradation. Microbial activity against hexadecane and certain carboxylated cycloalkanes was found to be nitrogen and phosphorus limited. 21 refs., 3 refs., 1 tab.

  19. 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

  20. Non-equilibrium and band tailing in organic conductors

    Indian Academy of Sciences (India)

    . Non-equilibrium due to coupling between applied energy and free electrons can be responsible for the exponential relaxation from non-equilibrium to equilibrium. Keywords. Band tailing; organic conductors; IR spectra; electrical resistivity.

  1. Mixtures of tails in clustered automobile collision claims

    NARCIS (Netherlands)

    R. Kalb (Reinhard); P. Kofman (Paul); A.C.F. Vorst (Ton)

    1996-01-01

    textabstractKnowledge of the tail shape of claim distributions provides important actuarial information. This paper discusses how two techniques commonly used in assessing the most appropriate underlying distribution can be usefully combined. The maximum likelihood approach is theoretically

  2. Relationship between tail lesions and lung health in slaughter pigs.

    Science.gov (United States)

    van Staaveren, Nienke; Vale, Ana P; Manzanilla, Edgar G; Teixeira, Dayane L; Leonard, Finola C; Hanlon, Alison; Boyle, Laura A

    2016-05-01

    Tail lesions are associated with poor health either because they serve as a point of entry for pathogens or because of shared risk factors. This study investigated the relationship between carcass tail lesion and lung lesion severity scores in slaughter pigs. Carcasses were scored after scalding/dehairing for tail lesion severity (0-4). Lungs were scored according to an adapted version of the BPEX pig health scheme. Severity of enzootic pneumonia (EP-like lesions) was recorded on a scale of 0-50. Severity of pleurisy was scored on a 0-2 scale with score 2 equating to severe pleurisy or those lungs that remained attached to the chest wall ('lungs in chest'). The database for assessing pleurisy lesions contained all pleurisy scores (n=5628). Lungs with a score of 2 for pleurisy were excluded from the analysis of all other lung lesions as such lungs could not be assessed for other lesions (n=4491). Associations between tail lesions and different lung lesion outcomes were analysed using generalized linear mixed models (PROC GLIMMIX) with random effect for batch. Males were more affected by moderate (OR=1.9, 95% CI 1.51-2.34) and severe (OR=5.8, 95% CI 3.45-9.70) tail lesions than females. EP-like lesions and pleurisy were most commonly observed. Pigs with severe tail lesions tended to have more 'lungs in chest' than pigs with moderate tail lesions (P=0.1). No other associations between tail lesions and lung lesions were found. Males had higher odds of having EP-like lesions (OR=1.2, 95% CI 1.05-1.36) than females. Tail lesions on the carcass may not be an accurate predictor of lung health. However, tail lesions are important welfare indicators and respiratory disease is a significant infectious condition affecting pigs. Thus, recording of tail and lung lesions at meat inspection provides valuable information regarding on-farm health and welfare of pigs. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  3. Lung cancer risks in the vicinity of uranium tailings sites

    International Nuclear Information System (INIS)

    Rogers, V.C.; Sandquist, G.M.

    1982-04-01

    Lung cancer mortality data have been assembled for many counties of interest to the Uranium Mill Tailings Remedial Action Program (UMTRAP). The counties generally either contain UMTRAP tailings sites or are adjacent to them. The lung cancer rates of nearly all counties are less than the US average rate. In addition, some of the many factors associated with lung cancer are identified as are cancer risk estimators for radon daughters. 17 refs., 19 figs., 1 tab

  4. Early sonographic findings suggestive of the human fetal tail.

    Science.gov (United States)

    Zimmer, E Z; Bronshtein, M

    1996-04-01

    The prenatal diagnosis of a human tail was suggested in six fetuses with ultrasound findings of an echogenic protrusion in the lumbo-sacral region. All fetuses were at 14-16 weeks' gestation. The ultrasound findings disappeared in all cases at 22-23 weeks. Dermal abnormalities such as pilonidal sinus, deep dimples, and scarred tissue were found in all six newborns. It is possible that the late regression of the embryonic human tail was the cause of these dermal findings.

  5. Controlled DNA compaction within chromatin: the tail-bridging effect

    OpenAIRE

    Muehlbacher, Frank; Holm, Christian; Schiessel, Helmut

    2005-01-01

    We study the mechanism underlying the attraction between nucleosomes, the fundamental packaging units of DNA inside the chromatin complex. We introduce a simple model of the nucleosome, the eight-tail colloid, consisting of a charged sphere with eight oppositely charged, flexible, grafted chains that represent the terminal histone tails. We demonstrate that our complexes are attracted via the formation of chain bridges and that this attraction can be tuned by changing the fraction of charged ...

  6. Engineering, environmental and economic planning for tailings disposal

    International Nuclear Information System (INIS)

    Poellot, J.H.

    1982-01-01

    There are two principal points made in this paper. First, mining waste materials, or tailings, are geotechnical materials. Their behavior follows the principles of soil mechanics and is predictable by these principles. Second, proper disposal, meaning safe, environmentally sound and economical disposal, requires planning and recognizing waste disposal as part of the total mining system and process. In the development of these two principles, planning, design, and economic considerations of mine tailings are discussed

  7. Testing tail-mounted transmitters with Myocastor coypus (nutria)

    Science.gov (United States)

    Merino, S.; Carter, J.; Thibodeaux, G.

    2007-01-01

    We developed a tail-mounted radio-transmitter for Myocastor coypus (nutria) that offers a practical and efficient alternative to collar or implant methods. The mean retention time was 96 d (range 57-147 d, n = 7), making this a practical method for short-term studies. The tail-mounts were less injurious to animals than collars and easier for field researchers to implement than either collars or surgically implanted transmitters.

  8. Tail Biting Trellis Representation of Codes: Decoding and Construction

    Science.gov (United States)

    Shao. Rose Y.; Lin, Shu; Fossorier, Marc

    1999-01-01

    This paper presents two new iterative algorithms for decoding linear codes based on their tail biting trellises, one is unidirectional and the other is bidirectional. Both algorithms are computationally efficient and achieves virtually optimum error performance with a small number of decoding iterations. They outperform all the previous suboptimal decoding algorithms. The bidirectional algorithm also reduces decoding delay. Also presented in the paper is a method for constructing tail biting trellises for linear block codes.

  9. User-Friendly Tail Bounds for Matrix Martingales

    Science.gov (United States)

    2011-01-16

    USER-FRIENDLY TAIL BOUNDS FOR MATRIX MARTINGALES JOEL A. TROPP ! Report Documentation Page Form ApprovedOMB No. 0704-0188...00-2011 4. TITLE AND SUBTITLE User-Friendly Tail Bounds for Matrix Martingales 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6...BOUNDS FOR MATRIX MARTINGALES JOEL A. TROPP Abstract. This report presents probability inequalities for sums of adapted sequences of random, self

  10. Fitting Heavy Tailed Distributions: The poweRlaw Package

    Directory of Open Access Journals (Sweden)

    Colin S. Gillespie

    2015-03-01

    Full Text Available Over the last few years, the power law distribution has been used as the data generating mechanism in many disparate fields. However, at times the techniques used to fit the power law distribution have been inappropriate. This paper describes the poweRlaw R package, which makes fitting power laws and other heavy-tailed distributions straightforward. This package contains R functions for fitting, comparing and visualizing heavy tailed distributions. Overall, it provides a principled approach to power law fitting.

  11. Preparation of polymeric aluminium ferric chloride from bauxite tailings

    Directory of Open Access Journals (Sweden)

    Ma D.

    2013-01-01

    Full Text Available Bauxite tailings are the main solid wastes in the ore dressing process. The Al2O3 and Fe2O3 contents in bauxite tailings can reach 50% and 13% respectively. The present study proposed a feasible method to use bauxite tailings to prepare polymeric aluminium ferric chloride (PAFC, a new composite inorganic polymer for water purification. Bauxite tailings roasted reacting with hydrochloric acid under air, pickle liquor which mainly contains Fe3+, Al3+ was generated, then calcium aluminate was used to adjust pH value and the basicity of the pickle liquor, the PAFC was subsequently prepared after the polymerization process. The optimal synthesizing parameters for the preparation of PAFC obtained were as follows: the concentration of hydrochloric acid of 24 wt%, ratio of hydrochloric acid to bauxite tailings of 6:1, temperature of 90ºC, leaching time of 2.5 hours, ration of pickle liquor to calcium aluminate of 12:1, polymerization temperature of 90ºC and polymerization time of about 3 hours. The basicity of PAFC was higher than 68%, the sum concentration of Al2O3 and Fe2O3 was beyond 12.5%. The results of flocculation tests indicate that the PAFC has a better performance of removing the turbidity of wastewater compared to PAC, and PAFC prepared by bauxite tailings is a kind of high quality flocculants.

  12. Long-term stabilization of uranium mill tailings

    Energy Technology Data Exchange (ETDEWEB)

    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%.

  13. 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%

  14. 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)

  15. Current practices and options for confinement of uranium mill tailings

    International Nuclear Information System (INIS)

    1981-01-01

    At the United Nations Conference on the Human Environment, which took place in Stockholm from 4 to 6 June 1972, national governments were asked to explore, with the International Atomic Energy Agency and other appropriate international organizations, international co-operation on radioactive waste matters including those of mining and tailings disposal. Since that time the IAEA has been active in the field of uranium and thorium mill tailings management. As part of this activity, the present report describes current practices and options for confinement of uranium mill tailings. It is addressed to technical and administrative personnel who are involved in planning and implementing national and industrial programmes on the management of such tailings. In 1974 and 1975 the IAEA convened meetings of experts to review matters of interest and importance in the management of uranium and thorium mine and mill tailings. These activities led to the publication in 1976 of Management of Wastes from the Mining and Milling of Uranium and Thorium Ores, a Code of Practice and Guide to the Code, IAEA Safety Series No. 44. As a continuation of this activity, the IAEA is here dealing more specifically with the design and siting considerations for the management of uranium mill tailings

  16. Suspended electrodialytic extraction of toxic elements for detoxification of three different mine tailings

    DEFF Research Database (Denmark)

    Jensen, Pernille Erland; Ottosen, Lisbeth M.; Hansen, H.K.

    2016-01-01

    have shown that electrokinetic treatment can remove Cd, Cu, Pb, and Zn from tailings soils; As from tailings; and Cu from tailings. Still, however, a major concern is the long treatment-time required for the element-transport through the tailings matrix. Therefore several enhancement methods have been...

  17. Prevalence of gastrointestinal parasites of stray dogs impounded by the Society for the Prevention of Cruelty to Animals (SPCA), Durban and Coast, South Africa.

    Science.gov (United States)

    Mukaratirwa, S; Singh, V P

    2010-06-01

    Coprological examination was used to determine the prevalence and intensity of gastrointestinal parasites of stray dogs impounded by the Society for the Prevention of Cruelty to Animals (SPCA), Durban and Coast, South Africa. Helminth and protozoan parasites were found in faeces of 240 dogs with an overall prevalence of 82.5% (helminth parasites 93.1% and protozoan parasites 6.9%). The following parasites and their prevalences were detected; Ancylostoma sp. (53.8%), Trichuris vulpis (7.9%), Spirocerca lupi (5.4%), Toxocara canis (7.9%), Toxascaris leonina (0.4%) Giardia intestinalis (5.6%) and Isospora sp. (1.3%). Dogs harbouring a single parasite species were more common (41.7%) than those harbouring 2 (15%) or multiple (2.1%) species. Ancylostoma sp., Toxocara canis and Giardia intestinalis have zoonotic potential and were detected in 66.7% of the samples.

  18. Prevalence of gastrointestinal parasites of stray dogs impounded by the Society for the Prevention of Cruelty to Animals (SPCA, Durban and Coast, South Africa : short communication

    Directory of Open Access Journals (Sweden)

    S. Mukaratirwa

    2010-05-01

    Full Text Available Coprological examination was used to determine the prevalence and intensity of gastrointestinal parasites of stray dogs impounded by the Society for the Prevention of Cruelty to Animals (SPCA, Durban and Coast, South Africa. Helminth and protozoan parasites were found in faeces of 240 dogs with an overall prevalence of 82.5% (helminth parasites 93.1% and protozoan parasites 6.9 %. The following parasites and their prevalences were detected; Ancylostoma sp. (53.8 %, Trichuris vulpis (7.9 %, Spirocerca lupi (5.4 %, Toxocara canis (7.9 %, Toxascaris leonina (0.4 % Giardia intestinalis (5.6 % and Isospora sp. (1.3 %. Dogs harbouring a single parasite species were more common (41.7 % than those harbouring 2 (15 % or multiple (2.1 % species. Ancylostoma sp., Toxocara canis and Giardia intestinalis have zoonotic potential and were detected in 66.7 % of the samples.

  19. The net GHG (CO2, CH4 and N2O) footprint of a newly impounded subtropical hydroelectric reservoir: Nam Theun 2

    Science.gov (United States)

    Deshmukh, Chandrashekhar; Guérin, Frédéric; Delon, Claire; Pighini, Sylvie; Vongkhamsao, Axay; Descloux, Stéphane; Chanudet, Vincent; Tardif, Raphael; Godon, Arnaud; Guédant, Pierre; Galy-Lacaux, Corinne; Zouiten, Cyril; Oliva, Priscia; Audry, Stéphane; Serça, Dominique

    2013-04-01

    There is a rising concern over the contribution of hydroelectric reservoirs to global anthropogenic greenhouse gases (GHGs) emissions. We present here the first comprehensive assessment of GHGs footprint associated with the creation of the Nam Theun 2 (NT2) hydroelectric reservoir in subtropical region of the Lao People's Democratic Republic. This assessment is the results of a monthly monitoring that have been conducted over 4 year (2008-to date). The carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) sources and sinks were quantified before and after impoundment, which began in May 2008. Before impoundment, the landscape to be flooded was a sink of carbon dioxide (-73 ± 225 Gg CO2eq yr-1),roughly neutral in terms of methane (7 ± 11 Gg CO2eq yr-1), and a source of nitrous oxide (345 ± 158 Gg CO2eq yr-1). After impoundment, total CO2 and CH4 emissions increased and N2O emissions decreased. For the year 2010, CO2 (791 ± 54 Gg CO2eq yr-1) and CH4 (644 ± 124 Gg CO2eq yr-1) contributed equally to the total gross GHG emissions from NT2 (54 and 43% for CO2 and CH4, respectively) whereas N2O contributed only 3% (47 ± 29 Gg CO2eq yr-1). The GHG emissions remained constant in 2011. Our results indicate that most of the GHG (around 90%) were emitted from reservoir water surface and the drawdown area, and only 10% were emitted by degassing at the turbines and from diffusive emissions downstream of the turbines and the dam, a percentage lower than reported for other hydroelectric reservoirs. With a total emissions of 1482 ± 207 and 1298 ± 200 Gg CO2eq yr-1 for year 2010 and 2011, gross NT2 emissions are about an order of magnitude higher than pre-impoundment emissions (276 ± 393 Gg CO2eq yr-1). With a net GHG emissions of 1203 ± 601 (2010) and 1022 ± 594 (2011) Gg CO2eq yr-1, and an annual power generation of about 6 TWh, GHG emission factor equal to 0.20 (2010) and 0.17 (2011) Mg CO2eq MWh-1 for NT2 which is up to five times lower than the emission factor

  20. Analysis of the histone protein tail and DNA in nucleosome using molecular dynamics simulation

    Science.gov (United States)

    Fujimori, R.; Komatsu, Y.; Fukuda, M.; Miyakawa, T.; Morikawa, R.; Takasu, M.

    2013-02-01

    We study the effect of the tails of H3 and H4 histones in the nucleosomes, where DNA and histones are packed in the form of chromatin. We perform molecular dynamics simulations of the complex of DNA and histones and calculate the mean square displacement and the gyration radius of the complex of DNA and histones for the cases with tails intact and the cases with tails missing. Our results show that the H3 tails are important for the motion of the histones. We also find that the motion of one tail is affected by other tails, although the tails are distanced apart, suggesting the correlated motion in biological systems.

  1. The Tail-Elicited Tail Withdrawal Reflex of "Aplysia" Is Mediated Centrally at Tail Sensory-Motor Synapses and Exhibits Sensitization across Multiple Temporal Domains

    Science.gov (United States)

    Philips, Gary T.; Sherff, Carolyn M.; Menges, Steven A.; Carew, Thomas J.

    2011-01-01

    The defensive withdrawal reflexes of "Aplysia californica" have provided powerful behavioral systems for studying the cellular and molecular basis of memory formation. Among these reflexes the (T-TWR) has been especially useful. In vitro studies examining the monosynaptic circuit for the T-TWR, the tail sensory-motor (SN-MN) synapses, have…

  2. Is rhizosphere remediation sufficient for sustainable revegetation of mine tailings?

    Science.gov (United States)

    Huang, Longbin; Baumgartl, Thomas; Mulligan, David

    2012-07-01

    Revegetation of mine tailings (fine-grained waste material) starts with the reconstruction of root zones, consisting of a rhizosphere horizon (mostly topsoil and/or amended tailings) and the support horizon beneath (i.e. equivalent to subsoil - mostly tailings), which must be physically and hydro-geochemically stable. This review aims to discuss key processes involved in the development of functional root zones within the context of direct revegetation of tailings and introduces a conceptual process of rehabilitating structure and function in the root zones based on a state transition model. Field studies on the revegetation of tailings (from processing base metal ore and bauxite residues) are reviewed. Particular focus is given to tailings' properties that limit remediation effectiveness. Aspects of root zone reconstruction and vegetation responses are also discussed. When reconstructing a root zone system, it is critical to restore physical structure and hydraulic functions across the whole root zone system. Only effective and holistically restored systems can control hydro-geochemical mobility of acutely and chronically toxic factors from the underlying horizon and maintain hydro-geochemical stability in the rhizosphere. Thereafter, soil biological capacity and ecological linkages (i.e. carbon and nutrient cycling) may be rehabilitated to integrate the root zones with revegetated plant communities into sustainable plant ecosystems. A conceptual framework of system transitions between the critical states of root zone development has been proposed. This will illustrate the rehabilitation process in root zone reconstruction and development for direct revegetation with sustainable plant communities. Sustainable phytostabilization of tailings requires the systematic consideration of hydro-geochemical interactions between the rhizosphere and the underlying supporting horizon. It further requires effective remediation strategies to develop hydro-geochemically stable

  3. Tail Docking and Ear Cropping Dogs: Public Awareness and Perceptions.

    Science.gov (United States)

    Mills, Katelyn E; Robbins, Jesse; von Keyserlingk, Marina A G

    2016-01-01

    Tail docking and ear cropping are two surgical procedures commonly performed on many dog breeds. These procedures are classified as medically unnecessary surgeries whose purpose is primarily cosmetic. Available attitude research surrounding these controversial practices has been limited to surveys of veterinarians and dog breeders familiar with both practices. The aim of this project was to: 1) assess public awareness of tail docking and ear cropping, 2) determine whether physical alteration of a dog affects how the dog, and 3) owner are perceived. In Experiment 1 awareness was measured using a combination of both explicit and implicit measures. We found that 42% of participants (n = 810) were unable to correctly explain the reason why tail docked and ear cropped dogs had short ears and tails. Similarly, an implicit measure of awareness ('nature vs nurture task'), found that the majority of participants believed short tails and erect ears were a consequence of genetics rather than something the owner or breeder had done. The results obtained in Experiment 2 (n = 392) provide evidence that ear cropped and tail docked dogs are perceived differently than an identical dog in its 'natural' state. Modified dogs were perceived as being more aggressive, more dominant, less playful and less attractive than natural dogs. Experiment 3 (n = 410) is the first evidence that owners of modified dogs are perceived as being more aggressive, more narcissistic, less playful, less talkative and less warm compared to owners of natural dogs. Taken together, these results suggest that although a significant proportion of subjects appear unaware of the practices of tail docking and ear cropping in dogs, these procedures have significant impacts on how modified dogs and their owners are perceived by others.

  4. Tail Docking and Ear Cropping Dogs: Public Awareness and Perceptions.

    Directory of Open Access Journals (Sweden)

    Katelyn E Mills

    Full Text Available Tail docking and ear cropping are two surgical procedures commonly performed on many dog breeds. These procedures are classified as medically unnecessary surgeries whose purpose is primarily cosmetic. Available attitude research surrounding these controversial practices has been limited to surveys of veterinarians and dog breeders familiar with both practices. The aim of this project was to: 1 assess public awareness of tail docking and ear cropping, 2 determine whether physical alteration of a dog affects how the dog, and 3 owner are perceived. In Experiment 1 awareness was measured using a combination of both explicit and implicit measures. We found that 42% of participants (n = 810 were unable to correctly explain the reason why tail docked and ear cropped dogs had short ears and tails. Similarly, an implicit measure of awareness ('nature vs nurture task', found that the majority of participants believed short tails and erect ears were a consequence of genetics rather than something the owner or breeder had done. The results obtained in Experiment 2 (n = 392 provide evidence that ear cropped and tail docked dogs are perceived differently than an identical dog in its 'natural' state. Modified dogs were perceived as being more aggressive, more dominant, less playful and less attractive than natural dogs. Experiment 3 (n = 410 is the first evidence that owners of modified dogs are perceived as being more aggressive, more narcissistic, less playful, less talkative and less warm compared to owners of natural dogs. Taken together, these results suggest that although a significant proportion of subjects appear unaware of the practices of tail docking and ear cropping in dogs, these procedures have significant impacts on how modified dogs and their owners are perceived by others.

  5. Black-tailed and white-tailed jackrabbits in the American West: History, ecology, ecological significance, and survey methods

    Science.gov (United States)

    Simes, Matthew; Longshore, Kathleen M.; Nussear, Kenneth E.; Beatty, Greg L.; Brown, David E.; Esque, Todd C.

    2015-01-01

    Across the western United States, Leporidae are the most important prey item in the diet of Golden Eagles (Aquila chrysaetos). Leporids inhabiting the western United States include black-tailed (Lepus californicus) and white-tailed jackrabbits (Lepus townsendii) and various species of cottontail rabbit (Sylvilagus spp.). Jackrabbits (Lepus spp.) are particularly important components of the ecological and economic landscape of western North America because their abundance influences the reproductive success and population trends of predators such as coyotes (Canis latrans), bobcats (Lynx rufus), and a number of raptor species. Here, we review literature pertaining to black-tailed and white-tailed jackrabbits comprising over 170 published journal articles, notes, technical reports, conference proceedings, academic theses and dissertations, and other sources dating from the late 19th century to the present. Our goal is to present information to assist those in research and management, particularly with regard to protected raptor species (e.g., Golden Eagles), mammalian predators, and ecological monitoring. We classified literature sources as (1) general information on jackrabbit species, (2) black-tailed or (3) white-tailed jackrabbit ecology and natural history, or (4) survey methods. These categories, especially 2, 3, and 4, were further subdivided as appropriate. The review also produced several tables on population trends, food habits, densities within various habitats, and jackrabbit growth and development. Black-tailed and white-tailed jackrabbits are ecologically similar in general behaviors, use of forms, parasites, and food habits, and they are prey to similar predators; but they differ in their preferred habitats. While the black-tailed jackrabbit inhabits agricultural land, deserts, and shrublands, the white-tailed jackrabbit is associated with prairies, alpine tundra, and sagebrush-steppe. Frequently considered abundant, jackrabbit numbers in western North

  6. Remediation of the Sillamae Radioactive Tailings Pond, Estonia

    International Nuclear Information System (INIS)

    Barnekow, U.; Jaaksoo, R.; Kaasik, T.

    2011-01-01

    The paper presents experiences gained and progress achieved during the ongoing Sillamaee Radioactive Tailings Pond Remediation Project. The Sillamaee tailings pond covering ca. 50 ha is located next to the shoreline of the Baltic Sea near Sillamaee town in Estonia. Tailings disposal included mill tailings from uranium ore processing (1953-1977), enriched uranium refining (1977- 1990), from rare earth elements processing (since 1970; tailings disposal ended 2003), black shale processing (1948-1953) and liquid oil-shale ashes from the local power plant. Initial environmental and geotechnical investigations identified insufficient safety of the tailings pond for radiological, environmental and geotechnical reasons. Contaminated seepage was entering the Baltic Sea. The 25 m high northern tailings dam was affected by marine erosion and the stability of the dam was found to be insufficient. Therefore the multi-national Sillamaee Radioactive Tailings Pond Remediation Programme was launched in 1998 jointly financed by North European Countries (NEFCO), EU and Estonia. The remediation project included the following crucial remediation steps: Drillings and samplings including geotechnical, (hydro-)geological and environmental investigations (2000-2001); relocation of mine wastes and contaminated soils from the surrounding area onto the tailings pond for interim covering (2000-2003); initial stabilization measures (2001-2003) including a 1080 m long shore protection embankment along the shoreline of the Baltic Sea, a 720 m long pile grillage for stabilizing the northern dam including two rows of 15 m or 18 m deep continuous flight auger piles, a 580 m long and 12-18 m deep cut-off wall, a deep gravel-filled drainage ditch (520 m, up to 12 m deep) and a deep drainage trench. Reshaping of the dams with respect to long term dam stability and contouring of the pond area with respect to long term settlement portions lasted from 2003 till 2004 building up a ridge-type surface

  7. 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

  8. 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

  9. Use of cemented paste backfill in arsenic-rich tailings

    Science.gov (United States)

    Hamberg, Roger; Maurice, Christian; Alakangas, Lena

    2015-04-01

    Gold is extracted by cyanide leaching from inclusions in arsenopyrite from a mine in the north of Sweden. The major ore mineral assemblage consists of pyrrhotite and arsenopyrite-loellingite. Effluents from the gold extraction were treated with Fe2(SO4)3, with the aim to form stable As-bearing Fe-precipitates (FEP). The use of the method called cemented paste backfill (CPB) is sometimes suggested for the management of tailings. In CPB, tailings are commonly mixed with low proportions (3 - 7 %) of cement and backfilled into underground excavated area. To reduce costs, amendments such as granulated blast furnace slag (GBFS), biofuel fly ash (BFA) and cement kiln dust (CKD) are used for partial replacement of cement in CPB due to their pozzolanic and alkaline properties. The objective for this study was to evaluate the leaching behaviour of As in CPB-mixtures with low proportions (1 - 3 %) of BFA and ordinary cement and unmodified tailings. The selection of CPB-recipies was made based on technical and economical criterias to adress the demands deriving from the mining operations. Speciation of the As in ore and tailings samples revealed that mining processes have dissolved the majority of the arsenopyrite in the ore, causing secondary As phases to co-precipitate with newly formed FEP:s. Tank leaching tests (TLT) and weathering cells (WCT) were used to compare leaching behaviour in a monolithic mass contra a crushed material. Quantification of the presumed benefit of CPB was made by calculation of the cumulative leaching of As. Results from the leaching tests (TLT and WCT) showed that the inclusion of As-rich tailings into a cementitious matrix increased leaching of As. This behaviour could partially be explained by an increase of pH. The addition of alkaline binder materials to tailings increased As leaching due to the relocation of desorbed As from FEPs into less acid-tolerant species such as Ca-arsenates and cementitious As-phases. Unmodified tailings generated an

  10. Changes in the fish community of the Kpong Headpond, lower Volta River, Ghana after 25 years of impoundment

    Directory of Open Access Journals (Sweden)

    Theodore Quarcoopome

    2011-12-01

    Full Text Available The Kpong Headpond was the second created on the Volta River after Akosombo Dam, primarily as a source of hydroelectric power generation and potable water supply, and additionally, it has supported some fish production in Ghana since impoundment. The changes in fish community of the Kpong Headpond were studied to provide baseline information for strategies formulation to support the socio-economic development of the reservoir. The study identified changes in the fish community of the reservoir by comparing occurrence, composition, relative abundance and relative importance estimates of fish species, families and trophic groups, from available previous studies in the reservoir. From the collated information all fishes identified in the reservoir were categorised based on occurrence and importance as disappeared, appeared, permanent, declined or important, to show current status. The results indicated that the fish community has experienced a shift in the composition and relative abundance of important species, families and trophic groups in terms of number and weight, while remaining ecologically balanced. Representatives of the families Osteoglossidae, Centropomidae and Characidae have declined while representatives of the families Claroteidae, Cyprinidae and Cichlidae have increased. The aufwuch-detritus and herbivores declined while semi-pelagic omnivores increased resulting in a shift in dominance to benthic and semi pelagic omnivores. The appearance of five species and the disappearance of 25 others indicated a dynamic restructuring of the fish community in the reservoir, as expected. Enforcement of fishing regulations including the use of appropriate gear and fishing methods, fishery access control, promotion of culture-based fisheries and improvement in fisher education are recommended topics for sustainable fisheries in the reservoir. Rev. Biol. Trop. 59 (4: 1685-1696. Epub 2011 December 01.La laguna Kpong se convirtió en la segunda

  11. Green remediation of tailings from the mine using inorganic agents

    Directory of Open Access Journals (Sweden)

    Došić Aleksandar D.

    2017-01-01

    Full Text Available Increasing amounts of residues and waste materials coming from industrial activities in different processes have become an increasingly urgent problem for the future. The paper presents the problem of mine tailings generated in mine “Sase” (Republic of Srpska, Bosnia and Herzegovina with high metal content (Pb, Cu and Zn. Dumpsite of this tailing represents potential risk for water bodies in the vicinity of this location. Chosen treatment process was stabilization/solidification (S/S. Inorganic agents used in this study were fly ash and red mud that represent secondary industrial waste generated on locations relatively near the mine. Therefore, their application can be used as an example of a sustainable solution of regional environmental problem. Further investigations are related to the impact of various factors on metals leaching from mine tailings solidified/stabilized material using the above mentioned immobilization agents. The performance of the immobilizing procedures was examined using several leaching tests: ANS 16.1, TCLP, DIN, MWLP. The results indicated that all S/S samples can be considered as non-hazardous waste, as all leached metal concentrations met the set criteria. These results will further enable the modelling of metals behaviour during long-term leaching from treated mine tailing. The data are invaluable in terms of economically and environmentally sound management of mine tailing.

  12. Tail dependence and information flow: Evidence from international equity markets

    Science.gov (United States)

    Al Rahahleh, Naseem; Bhatti, M. Ishaq; Adeinat, Iman

    2017-05-01

    Bhatti and Nguyen (2012) used the copula approach to measure the tail dependence between a number of international markets. They observed that some country pairs exhibit only left-tail dependence whereas others show only right-tail. However, the flow of information from uni-dimensional (one-tail) to bi-dimensional (two-tails) between various markets was not accounted for. In this study, we address the flow of information of this nature by using the dynamic conditional correlation (DCC-GARCH) model. More specifically, we use various versions of the DCC models to explain the nexus between the information flow of international equity and to explain the stochastic forward vs. backward dynamics of financial markets based on data for a 15-year period comprising 3,782 observations. We observed that the information flow between the US and Hong Kong markets and between the US and Australian markets are bi-directional. We also observed that the DCC model captures a wider co-movement structure and inter-connectedness compared to the symmetric Joe-Clayton copula.

  13. 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.

  14. Characterization of Emergent Data Networks Among Long-Tail Data

    Science.gov (United States)

    Elag, Mostafa; Kumar, Praveen; Hedstrom, Margaret; Myers, James; Plale, Beth; Marini, Luigi; McDonald, Robert

    2014-05-01

    Data curation underpins data-driven scientific advancements. It manages the information flux across multiple users throughout data life cycle as well as increases data sustainability and reusability. The exponential growth in data production spanning across the Earth Science involving individual and small research groups, which is termed as log-tail data, increases the data-knowledge latency among related domains. It has become clear that an advanced framework-agnostic metadata and ontologies for long-tail data is required to increase their visibility to each other, and provide concise and meaningful descriptions that reveal their connectivity. Despite the advancement that has been achieved by various sophisticated data management models in different Earth Science disciplines, it is not always straightforward to derive relationships among long-tail data. Semantic data clustering algorithms and pre-defined logic rules that are oriented toward prediction of possible data relationships, is one method to address these challenges. Our work advances the connectivity of related long-tail data by introducing the design for an ontology-based knowledge management system. In this work, we present the system architecture, its components, and illustrate how it can be used to scrutinize the connectivity among datasets. To demonstrate the capabilities of this "data network" prototype, we implemented this approach within the Sustainable Environment Actionable Data (SEAD) environment, an open-source semantic content repository that provides a RDF database for long-tail data, and show how emergent relationships among datasets can be identified.

  15. Regeneration of neural crest derivatives in the Xenopus tadpole tail

    Directory of Open Access Journals (Sweden)

    Slack Jonathan MW

    2007-05-01

    Full Text Available Abstract Background After amputation of the Xenopus tadpole tail, a functionally competent new tail is regenerated. It contains spinal cord, notochord and muscle, each of which has previously been shown to derive from the corresponding tissue in the stump. The regeneration of the neural crest derivatives has not previously been examined and is described in this paper. Results Labelling of the spinal cord by electroporation, or by orthotopic grafting of transgenic tissue expressing GFP, shows that no cells emigrate from the spinal cord in the course of regeneration. There is very limited regeneration of the spinal ganglia, but new neurons as well as fibre tracts do appear in the regenerated spinal cord and the regenerated tail also contains abundant peripheral innervation. The regenerated tail contains a normal density of melanophores. Cell labelling experiments show that melanophores do not arise from the spinal cord during regeneration, nor from the mesenchymal tissues of the skin, but they do arise by activation and proliferation of pre-existing melanophore precursors. If tails are prepared lacking melanophores, then the regenerates also lack them. Conclusion On regeneration there is no induction of a new neural crest similar to that seen in embryonic development. However there is some regeneration of neural crest derivatives. Abundant melanophores are regenerated from unpigmented precursors, and, although spinal ganglia are not regenerated, sufficient sensory systems are produced to enable essential functions to continue.

  16. Intraspecific competition, not predation, drives lizard tail loss on islands.

    Science.gov (United States)

    Itescu, Yuval; Schwarz, Rachel; Meiri, Shai; Pafilis, Panayiotis

    2017-01-01

    Tail autotomy is mainly considered an antipredator mechanism. Theory suggests that predation pressure relaxes on islands, subsequently reducing autotomy rates. Intraspecific aggression, which may also cause tail loss, probably intensifies on islands due to the higher abundance. We studied whether tail autotomy is mostly affected by predation pressure or by intraspecific competition. We further studied whether predator abundance or predator richness is more important in this context. To test our predictions, we examined multiple populations of two gecko species: Kotschy's gecko (Mediodactylus kotschyi; mainland and 41 islands) and the Mediterranean house gecko (Hemidactylus turcicus; mainland and 17 islands), and estimated their abundance together with five indices of predation. In both species, autotomy rates are higher on islands and decline with most predation indices, in contrast with common wisdom, and increase with gecko abundance. In M. kotschyi, tail-loss rates are higher on predator and viper-free islands, but increase with viper abundance. We suggest that autotomy is not simply, or maybe even mainly, an antipredatory mechanism. Rather, such defence mechanisms are a response to complex direct and indirect biotic interactions and perhaps, in the case of tail autotomy in insular populations, chiefly to intraspecific aggression. © 2016 The Authors. Journal of Animal Ecology © 2016 British Ecological Society.

  17. 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

  18. Denitrification in groundwater at uranium mill tailings sites

    International Nuclear Information System (INIS)

    Goering, Timothy J.; Groffman, Armando; Thomson, Bruce

    1992-01-01

    Nitrates are a major contaminant in groundwater at many Uranium Mill Tailings Remedial Action (UMTRA) sites. Microbial denitrification, the transformation of nitrate to nitrogen gas, may be occurring in groundwater at several UMTRA sites. Denitrification is a biologically mediated process whereby facultative anaerobes use nitrate for respiration under anaerobic conditions. Denitrifying bacteria are ubiquitous in soils, sediments, and water. Denitrification requires nitrate, organic carbon, oxygen-limiting conditions, and trace nutrients, especially phosphorus. The lack of organic carbon is the most common limiting factor for denitrification. Denitrification occurs under a limited range of temperature and pH. The uranium milling processes used at UMTRA sites provided a readily available source of carbon and nitrates for denitrifying bacteria. At the Maybell, Colorado, site, the denitrifying organisms Pseudomonas, Flavobacterium and Acinetobacter were identified in core samples of materials from beneath the tailings. In addition, microcosm experiments simulating aquifer conditions beneath the tailings pile showed an average 40 percent decrease in nitrate concentrations over 13 days. At the New Rifle, Colorado, site, aquifer conditions appear favorable for denitrification. Nitrate and organic carbon are readily available in the groundwater, and redox conditions beneath and downgradient of the tailings pile are relatively anoxic. Downgradient from the tailings, total nitrogen is being removed from the groundwater system at a greater rate than the geochemically conservative anion, chloride. This removal may be due to denitrification and adsorption of ammonium onto clay and silt particles. (author)

  19. Field experiment on 222Rn flux from reclaimed uranium tailings

    International Nuclear Information System (INIS)

    Hinton, T.G.

    1983-01-01

    Design and construction techniques are described for a 1.6 ha experimental uranium mill tailings reclamation plot. A passive, activated charcoal device was developed and tested for measurements of radon flux. Experiments on radon flux versus overburden depth showed that tailings covered with 1.5 m of revegetated or 0.3 m of bare overburden had exhalation rates comparable to background. Vegetated subplots exhibited a significantly higher (often an order of magnitude) flux than the bare subplots. Results on the variation of flux over time did not reveal any definitive patterns, possibly due to the high variability among replicates. A positive correlation was demonstrated between precipitation and radon flux. This is discussed in detail and possibly explained by the increase in water content of the micropores within the tailings, which increases the emanation coefficient without adversely effecting the diffusion coefficient of the overburden. 30 references, 7 figures, 3 tables

  20. News from the Library: The 'long tail' Library

    CERN Multimedia

    CERN Library

    2012-01-01

    "The term 'long tail' has gained popularity in recent times as describing the retailing strategy of selling a large number of unique items with relatively small quantities sold of each usually in addition to selling fewer popular items in large quantities. The long tail was popularized by Chris Anderson, who mentioned Amazon.com, Apple and Yahoo! as examples of businesses applying this strategy." *   If we leave the business environment and move to the world of libraries, we still see this "long tail". Usually, only a small portion of a library's book collection accounts for the majority of its loans. On the other hand, there are a variety of "niche information needs" that might not be met, as libraries cannot afford to build up huge collections of documents available just-in-case. However, the networked environment of today's libraries can offer a solution. Online networks of libraries ca...

  1. Static magnetic field influence on rat tail nerve function.

    Science.gov (United States)

    Hong, C Z; Harmon, D; Yu, J

    1986-10-01

    Motor nerve conduction and excitability were measured on the tail nerve of anesthetized rats before and after the nerve was exposed perpendicularly to a static electromagnetic field of various intensities and durations. There was no significant change in either the distal latencies or the amplitudes of the compound muscle action potential (CMAP) measured from stimulating the tail nerve after it was exposed to the electromagnetic field with a density up to 1.2 Tesla (T) for a duration of 60 seconds. However, the nerve excitability expressed as changes of the amplitudes of the submaximally evoked CMAP increased significantly when the tail nerve was exposed to a magnetic field with a density higher than 0.5T for more than 30 seconds. The finding that an electromagnetic field increases motor nerve excitability suggests a possible mechanism of its therapeutic effects.

  2. Environmental Risk Assessment System for Phosphogypsum Tailing Dams

    Directory of Open Access Journals (Sweden)

    Xin Sun

    2013-01-01

    Full Text Available This paper may be of particular interest to the readers as it provides a new environmental risk assessment system for phosphogypsum tailing dams. In this paper, we studied the phosphogypsum tailing dams which include characteristics of the pollution source, environmental risk characteristics and evaluation requirements to identify the applicable environmental risk assessment methods. Two analytical methods, that is, the analytic hierarchy process (AHP and fuzzy logic, were used to handle the complexity of the environmental and nonquantitative data. Using our assessment method, different risk factors can be ranked according to their contributions to the environmental risk, thereby allowing the calculation of their relative priorities during decision making. Thus, environmental decision-makers can use this approach to develop alternative management strategies for proposed, ongoing, and completed PG tailing dams.

  3. A case of tail self-mutilation in a cat

    Directory of Open Access Journals (Sweden)

    Zita Talamonti

    2017-03-01

    Full Text Available The present report describes a case of distal tail self-mutilation in a 5-year-old neutered male domestic short-hair cat. The cat started licking his tail few months before the behavioural visit. Because of the severity of the self-induced injuries, the veterinarian performed a surgical partial caudectomy. After 3 months, the excessive self-grooming of the tail recurred. Neurological and dermatological examinations, radiographs, urine and blood tests did not show any abnormalities. During the behavioural visit, through direct observation of the cat’s posture and behavioural history, the pet received a diagnosis of psychogenic alopecia. The cat was treated with clomipramine for 2 months (0.5 mg/kg/PO SID along with behaviour modification and environmental changes. After 1 month, the cat no longer showed excessive self-grooming. Even if no other systemic pathologies were identified, it is always recommended to address these patients with a multidisciplinary approach.

  4. Guidelines for cleanup of uranium tailings from inactive mills

    International Nuclear Information System (INIS)

    Goldsmith, W.A.; Haywood, F.F.; Jacobs, D.G.

    1975-01-01

    Recent experiences in Grand Junction, Colorado, have indicated the significance of uranium tailings as sources of nonoccupational exposure and suggest that current methods for perpetual care and isolation of the large areas covered by tailings piles at inactive mill locations may be inadequate for minimizing human exposure. This paper presents the rationale and the procedures used in reviewing the adequacy of proposed criteria for remedial action at these sites. Exposures due to aquatic, terrestrial, airborne, and direct contamination pathways were compared to determine the most important radionuclides in the pile and their pathways to man. It is shown that the most hazardous components of the tailings are 226 Ra and 230 Th. The long half-lives of these radionuclides require the consideration of continuous occupancy of the vacated site at some future time, even if the immediately projected land use does not anticipate maximum exposure

  5. Efficient simulation of tail probabilities of sums of correlated lognormals

    DEFF Research Database (Denmark)

    Asmussen, Søren; Blanchet, José; Juneja, Sandeep

    We consider the problem of efficient estimation of tail probabilities of sums of correlated lognormals via simulation. This problem is motivated by the tail analysis of portfolios of assets driven by correlated Black-Scholes models. We propose two estimators that can be rigorously shown...... to be efficient as the tail probability of interest decreases to zero. The first estimator, based on importance sampling, involves a scaling of the whole covariance matrix and can be shown to be asymptotically optimal. A further study, based on the Cross-Entropy algorithm, is also performed in order to adaptively...... optimize the scaling parameter of the covariance. The second estimator decomposes the probability of interest in two contributions and takes advantage of the fact that large deviations for a sum of correlated lognormals are (asymptotically) caused by the largest increment. Importance sampling...

  6. Lead isotopes as seepage indicators around a uranium tailings dam

    International Nuclear Information System (INIS)

    Gulson, B.L.; Mizon, K.J.; Korsch, M.J.; Noller, B.N.

    1989-01-01

    Lead isotope ratios and lead concentrations have been measured in water from 26 bores around the Ranger uranium tailings dam, Northern Territory, Australia, and from the dam itself to determine possible migration of lead derived from the radioactive decay of uranium. Lead isotope compositions have also been measured for the particulates retained on selected filters. The concentration of lead in the bore waters is extremely low (usually 206 Pb/ 204 Pb ratio measured in the bore waters differs by more than a factor of 100 from that in the tailings dam and shows no evidence of lead derived from a significant uranium accumulation. It may be possible to distinguish between lead from the tailings dam and that derived from a nearby uranium ore body

  7. Environmental risk assessment system for phosphogypsum tailing dams.

    Science.gov (United States)

    Sun, Xin; Ning, Ping; Tang, Xiaolong; Yi, Honghong; Li, Kai; Zhou, Lianbi; Xu, Xianmang

    2013-01-01

    This paper may be of particular interest to the readers as it provides a new environmental risk assessment system for phosphogypsum tailing dams. In this paper, we studied the phosphogypsum tailing dams which include characteristics of the pollution source, environmental risk characteristics and evaluation requirements to identify the applicable environmental risk assessment methods. Two analytical methods, that is, the analytic hierarchy process (AHP) and fuzzy logic, were used to handle the complexity of the environmental and nonquantitative data. Using our assessment method, different risk factors can be ranked according to their contributions to the environmental risk, thereby allowing the calculation of their relative priorities during decision making. Thus, environmental decision-makers can use this approach to develop alternative management strategies for proposed, ongoing, and completed PG tailing dams.

  8. Accelerating transient drainage from UMTRA Project tailings piles

    International Nuclear Information System (INIS)

    1990-09-01

    The period between the completion of construction of the tailings disposal cell and the establishment of equilibrium moisture content and seepage conditions is considered to be the period of transient drainage. Transient drainage may be due to factors such as construction water, precipitation, or residual water from the milling process. Transient seepage rates usually exceed steady state seepage rates. If the transient seepage rate causes contaminant levels to exceed groundwater compliance standards, then an alternative groundwater compliance strategy or technical approach to reduce or mitigate the effects of the drainage must be adopted. This study examines methods to accelerate the transient drainage of soils and hence to remove excess pore water from tailings in UMTRA Project disposal cells. The technical and economic feasibility of possible methods is examined. In order to perform comparative economical analyses of the various methods, an example tailings pile is postulated. This pile is considered to be 300 meters by 300 meters by 10 meters in thickness

  9. Asphalt emulsion sealing of uranium mill tailings. 1980 annual report

    Energy Technology Data Exchange (ETDEWEB)

    Hartley, J.N.; Koehmstedt, P.L; Esterl, D.J.; Freeman, H.D.; Buelt, J.L.; Nelson, D.A.; Elmore, M.R.

    1981-05-01

    Studies of asphalt emulsion sealants conducted by the Pacific Northwest Laboratory have demonstrated that the sealants are effective in containing radon and other potentially hazardous material within uranium tailings. The laboratory and field studies have further demonstrated that radon exhalation from uranium tailings piles can be reduced by greater than 99% to near background levels. Field tests at the tailings pile in Grand Junction, Colorado, confirmed that an 8-cm admix seal containing 22 wt% asphalt could be effectively applied with a cold-mix paver. Other techniques were successfully tested, including a soil stabilizer and a hot, rubberized asphalt seal that was applied with a distributor truck. After the seals were applied and compacted, overburden was applied over the seal to protect the seal from ultraviolet degradation.

  10. Asphalt emulsion sealing of uranium mill tailings. 1980 annual report

    International Nuclear Information System (INIS)

    Hartley, J.N.; Koehmstedt, P.L; Esterl, D.J.; Freeman, H.D.; Buelt, J.L.; Nelson, D.A.; Elmore, M.R.

    1981-05-01

    Studies of asphalt emulsion sealants conducted by the Pacific Northwest Laboratory have demonstrated that the sealants are effective in containing radon and other potentially hazardous material within uranium tailings. The laboratory and field studies have further demonstrated that radon exhalation from uranium tailings piles can be reduced by greater than 99% to near background levels. Field tests at the tailings pile in Grand Junction, Colorado, confirmed that an 8-cm admix seal containing 22 wt% asphalt could be effectively applied with a cold-mix paver. Other techniques were successfully tested, including a soil stabilizer and a hot, rubberized asphalt seal that was applied with a distributor truck. After the seals were applied and compacted, overburden was applied over the seal to protect the seal from ultraviolet degradation

  11. Commingled uranium-tailings study. Volume II. Technical report

    Energy Technology Data Exchange (ETDEWEB)

    None

    1982-06-30

    Public Law 96-540, Section 213, directs the Secretary of Energy to develop a plan for a cooperative program to provide assistance in the stabilization and management of defense-related uranium mill tailings commingled with other tailings. In developing the plan, the Secretary is further directed to: (1) establish the amount and condition of tailings generated under federal contracts; (2) examine appropriate methodologies for establishing the extent of federal assistance; and (3) consult with the owners and operators of each site. This technical report summarizes US Department of Energy (DOE) and contractor activities in pursuit of items (1), (2), and (3) above. Recommendations regarding policy and a cooperative plan for federal assistance are under separate cover as Volume I.

  12. Radon diffusion in candidate soils for covering uranium mill tailings

    Energy Technology Data Exchange (ETDEWEB)

    Silker, W.B.; Kalkwarf, D.R.

    1983-04-01

    Diffusion coefficients were measured for radon in 34 soils that had been identified by mill personnel as candidate covers for their tailings piles in order to reduce radon emission. These coefficients referred to diffusion in the total pore space of the soils. They were measured in the laboratory by a steady-state method using soil columns compacted to greater than 80% of their Proctor maximum packing densities but with moisture contents generally less than would be expected at a tailings site. An empirical equation was used to extrapolate measured coefficients to value expected at soil-moisture contents representative of tailings sites in the western United States. Extrapolated values for silty sands and clayey sands ranged from 0.004 to 0.06 cm/sup 2//s. Values for inorganic silts and clays ranged from 0.001 to 0.02 cm/sup 2//s.

  13. The Anatomy of the Long Tail of Consumer Demand

    Science.gov (United States)

    Broder, Andrei

    The long tail of consumer demand is consistent with two fundamentally different theories. The first, and more popular hypothesis, is that a majority of consumers have similar tastes and only few have any interest in niche content; the second, is that everyone is a bit eccentric, consuming both popular and niche products. By examining extensive data on user preferences for movies, music, web search, and web browsing, we found overwhelming support for the latter theory. Our investigation suggests an additional factor in the success of "infinite-inventory" retailers such as Netflix and Amazon: besides the significant revenue obtained from tail sales, tail availability may boost head sales by offering consumers the convenience of "one-stop shopping" for both their mainstream and niche interests.

  14. Recent radiochemistry observations at the Riverton and Maybell tailings piles

    International Nuclear Information System (INIS)

    Smith, A.R.; Moed, B.A.

    1982-09-01

    Preliminary results are presented from the radiochemistry effort of the Lawrence Berkeley Laboratory integrated study of the inactive uranium mill tailings sites at Riverton, Wyoming and Maybell, Colorado. These results were obtained primarily by use of #betta#-ray spectrometric techniques, and included both field and laboratory application of NaI(Tl) crystal and Ge-semiconductor detector systems. Current interpretation of this evidence indicated there has been downward migration of uranium within the tailings column since its emplacement, and upward movement of several radionuclides from the tailings into the overlying cover material. The mechanisms responsible for these migrations are believed to involve fluid transport, and are further believed to be active at the present time

  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.

    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

  16. Langmuir monolayers composed of single and double tail sulfobetaine lipids.

    Science.gov (United States)

    Hazell, Gavin; Gee, Anthony P; Arnold, Thomas; Edler, Karen J; Lewis, Simon E

    2016-07-15

    Owing to structural similarities between sulfobetaine lipids and phospholipids it should be possible to form stable Langmuir monolayers from long tail sulfobetaines. By modification of the density of lipid tail group (number of carbon chains) it should also be possible to modulate the two-dimensional phase behaviour of these lipids and thereby compare with that of equivalent phospholipids. Potentially this could enable the use of such lipids for the wide array of applications that currently use phospholipids. The benefit of using sulfobetaine lipids is that they can be synthesised by a one-step reaction from cheap and readily available starting materials and will degrade via different pathways than natural lipids. The molecular architecture of the lipid can be easily modified allowing the design of lipids for specific purposes. In addition the reversal of the charge within the sulfobetaine head group relative to the charge orientation in phospholipids may modify behaviour and thereby allow for novel uses of these surfactants. Stable Langmuir monolayers were formed composed of single and double tailed sulfobetaine lipids. Surface pressure-area isotherm, Brewster Angle Microscopy and X-ray and neutron reflectometry measurements were conducted to measure the two-dimensional phase behaviour and out-of-plane structure of the monolayers as a function of molecular area. Sulfobetaine lipids are able to form stable Langmuir monolayers with two dimensional phase behaviour analogous to that seen for the well-studied phospholipids. Changing the number of carbon tail groups on the lipid from one to two promotes the existence of a liquid condensed phase due to increased Van der Waals interactions between the tail groups. Thus the structure of the monolayers appears to be defined by the relative sizes of the head and tail groups in a predictable way. However, the presence of sub-phase ions has little effect on the monolayer structure, behaviour that is surprisingly different to

  17. Uranium Mill Tailings Radiation Control Act of 1978

    International Nuclear Information System (INIS)

    Magee, J.

    1980-01-01

    The long-term environmental effects of the Uranium Mill Tailings Radiation Control Act of 1978 address the public health hazards of radioactive wastes and recognize the significance of this issue to public acceptance of nuclear energy. Title I of the Act deals with stabilizing and controlling mill tailings at inactive sites and classifies the sites by priority. It represents a major Federal commitment. Title II changes and strengthens Nuclear Regulatory Commission authority, but it will have little overall impact. It is not possible to assess the Act's effect because there is no way to know if current technology will be adequate for the length of time required. 76 references

  18. Adoption in rock and white-tailed ptarmigan

    Science.gov (United States)

    Wong, M.M.L.; Fedy, B.C.; Wilson, S.; Martin, K.M.

    2009-01-01

    Reports of adoption in birds are widespread, but few studies report rates of adoption or possible mechanisms for this phenomenon, particularly in the Order Galliformes. We report incidents of adoption in Rock Ptarmigan (Lagopus muta) and White-tailed Ptarmigan (L. leucura) from two sites in western Canada. Adoption rates for White-tailed Ptarmigan on Vancouver Island, British Columbia, and the Ruby Ranges, Yukon Territory were 13% (n = 16 broods) and 4% (n = 27), respectively, while rates for Rock Ptarmigan were 14% (n = 29) in the Ruby Ranges. Low brood densities may result in lower rates of adoption for ptarmigan. ?? 2009 The Wilson Ornithological Society.

  19. Tailings dam-break flow - Analysis of sediment transport

    Science.gov (United States)

    Aleixo, Rui; Altinakar, Mustafa

    2015-04-01

    A common solution to store mining debris is to build tailings dams near the mining site. These dams are usually built with local materials such as mining debris and are more vulnerable than concrete dams (Rico et al. 2008). of The tailings and the pond water generally contain heavy metals and various toxic chemicals used in ore extraction. Thus, the release of tailings due to a dam-break can have severe ecological consequences in the environment. A tailings dam-break has many similarities with a common dam-break flow. It is highly transient and can be severely descructive. However, a significant difference is that the released sediment-water mixture will behave as a non-Newtonian flow. Existing numerical models used to simulate dam-break flows do not represent correctly the non-Newtonian behavior of tailings under a dam-break flow and may lead to unrealistic and incorrect results. The need for experiments to extract both qualitative and quantitative information regarding these flows is therefore real and actual. The present paper explores an existing experimental data base presented in Aleixo et al. (2014a,b) to further characterize the sediment transport under conditions of a severe transient flow and to extract quantitative information regarding sediment flow rate, sediment velocity, sediment-sediment interactions a among others. Different features of the flow are also described and analyzed in detail. The analysis is made by means of imaging techniques such as Particle Image Velocimetry and Particle Tracking Velocimetry that allow extracting not only the velocity field but the Lagrangian description of the sediments as well. An analysis of the results is presented and the limitations of the presented experimental approach are discussed. References Rico, M., Benito, G., Salgueiro, AR, Diez-Herrero, A. and Pereira, H.G. (2008) Reported tailings dam failures: A review of the European incidents in the worldwide context , Journal of Hazardous Materials, 152, 846

  20. Crops for biodiesel to be grown on mine tailings

    Energy Technology Data Exchange (ETDEWEB)

    Ulrichsen, H.

    2007-12-01

    Natural Resources Canada has launched a feasibility project along with several branches of the federal government, provincial government, Laurentian University and mining and forestry companies to determine if crops suitable for producing biodiesel fuel can be grown on mine tailings. The concept first came about when a biodiesel plant was proposed to be built in Sudbury. Although plans for the plant have been abandoned, the biodiesel crop project is still going ahead. Crops will be cultivated on 2 half-hectare plots on the CVRD Inco tailings in Sudbury, 1 half-hectare plot on the Xstrata Nickel tailings in Sudbury and 1 half-hectare plot on the Goldcorp tailings in Timmins. Paper sludge from St. Marys Paper Company in Sault Ste. Marie and Domtar in Espanola will be spread on the plots in January when the frozen ground is easier to work on with heavy equipment. In the spring, the plots will be seeded with corn, canola or soy, with the possibility of alder and willow in the future. Instruments to monitor groundwater on the sites will also be installed. Biodiesel produced with vegetable or meat oils has been touted as being an environmentally sound diesel fuel. Emissions from vehicles fueled by biodiesel are 40 to 100 per cent lower than those from conventional diesel engines. Proponents of the project emphasize the value of using marginal lands like mine tailings to grow crops for biodiesel fuel instead of prime agricultural land. There are 2,500 hectares of tailings in Sudbury that could be potentially used for this purpose, and about 2,000 hectares at one mine site in Timmins. A Sudbury-area farmer will provide advice about growing the crops and will also grow the same crops on a portion of his land for a comparative evaluation of crop yield. The paper sludge offers the benefit of allowing crops to be grown, but it also cuts off oxygen flow to the tailings underneath, thereby preventing sulphides in the tailings from rusting. The paper sludge may even help the

  1. Fast head-tail instability with space charge

    Directory of Open Access Journals (Sweden)

    M. Blaskiewicz

    1998-08-01

    Full Text Available The fast head-tail instability with space charge is studied using series expansion techniques, numerical simulations, and a new formulation which allows for precise estimates of growth rates and thresholds. In regimes where they are reliable, all three techniques predict that space charge suppresses the fast head-tail instability. It is found that the series expansion techniques are unreliable for parameter regimes commonly employed in hadron accelerators. The numerical techniques are less prone to error, but the computational requirements become severe as space charge tune shifts increase. The new model has neither of these problems, but it underestimates the benefits of chromaticity, at least in its simplest form.

  2. Effect of surface treatment of tailings on effluent quality

    International Nuclear Information System (INIS)

    Murray, D.R.; Okuhara, D.

    1980-01-01

    Lysimeters containing 125 tons of mine tailings were used to determine the impact of gravel, sawdust, and vegetation as surface treatments on the quality and quantity of effluent produced from sulfide-containing uranium mill tailings. Over a 5-yr period, treatments did not alter the effluent quality to a level acceptable to regulatory requirements. The concentration of iron, copper, lead, aluminum, and sulfate increased with the rise of acidity during this period. However, the rate and extent of changes did vary with the treatment. The role of surface treatment in long-term waste abandonment must be investigated further

  3. Disease Limits Populations: Plague and Black-Tailed Prairie Dogs

    OpenAIRE

    Cully, Jack F.; Johnson, Tammi L.; Collinge, Sharon K.; Ray, Chris

    2010-01-01

    Plague is an exotic vector-borne disease caused by the bacterium Yersinia pestis that causes mortality rates approaching 100% in black-tailed prairie dogs (Cynomys ludovicianus). We mapped the perimeter of the active portions of black-tailed prairie dog colonies annually between 1999 and 2005 at four prairie dog colony complexes in areas with a history of plague, as well as at two complexes that were located outside the distribution of plague at the time of mapping and had therefore never bee...

  4. Improving "tail" computations in a BOINC-based Desktop Grid

    Science.gov (United States)

    Kolokoltsev, Yevgeniy; Ivashko, Evgeny; Gershenson, Carlos

    2017-12-01

    A regular Desktop Grid bag-of-tasks project can take a lot of time to complete computations. An important part of the process is tail computations: when the number of tasks to perform becomes less than the number of computing nodes. At this stage, a dynamic replication could be used to reduce the time needed to complete computations. In this paper, we propose a mathematical model and a strategy of dynamic replication at the tail stage. The results of the numerical experiments are given.

  5. Targeting ADAM12 in human disease: head, body or tail?

    DEFF Research Database (Denmark)

    Jacobsen, J; Wewer, U M

    2009-01-01

    properties. This functional trinity is reflected in the structure of ADAM12, which can be divided into head, body, and tail. The head of the protein (consisting of the pro and catalytic domains) mediates processing of growth factors and cytokines and has been implicated in epidermal growth factor (EGF......) and insulin-like growth factor receptor signaling. The body of the protein (consisting of the disintegrin, cysteine-rich, and EGF-like domains) is involved in contacts with the extracellular matrix and other cells through interactions with integrins and syndecans. Finally, the tail of the protein (consisting...... the possible approaches to targeting ADAM12 in human disease....

  6. Wake patterns of the wings and tail of hovering hummingbirds

    Science.gov (United States)

    Altshuler, Douglas L.; Princevac, Marko; Pan, Hansheng; Lozano, Jesse

    The flow fields of slowly flying bats and fasterflying birds differ in that bats produce two vortex loops during each stroke, one per wing, and birds produce a single vortex loop per stroke. In addition, the circulation at stroke transition approaches zero in bats but remains strong in birds. It is unknown if these difference derive from fundamental differences in wing morphology or are a consequence of flight speed. Here, we present an analysis of the horizontal flow field underneath hovering Anna's hummingbirds (Calypte anna) to describe the wake of a bird flying at zero forward velocity. We also consider how the hummingbird tail interacts with the wake generated by the wings. High-speed image recording and analysis from three orthogonal perspectives revealed that the wing tips reach peak velocities in the middle of each stroke and approach zero velocity at stroke transition. Hummingbirds use complex tail kinematic patterns ranging from in phase to antiphase cycling with respect to the wings, covering several phase shifted patterns. We employed particle image velocimetry to attain detailed horizontal flow measurements at three levels with respect to the tail: in the tail, at the tail tip, and just below the tail. The velocity patterns underneath the wings indicate that flow oscillates along the ventral-dorsal axis in response to the down- and up-strokes and that the sideways flows with respect to the bird are consistently from the lateral to medial. The region around the tail is dominated by axial flows in dorsal to ventral direction. We propose that these flows are generated by interaction between the wakes of the two wings at the end of the upstroke, and that the tail actively defects flows to generate moments that contribute to pitch stability. The flow fields images also revealed distinct vortex loops underneath each wing, which were generated during each stroke. From these data, we propose a model for the primary flow structures of hummingbirds that more

  7. Three Tails of Organizational Innovation: from the Value Creation Perspective

    DEFF Research Database (Denmark)

    Lin, Chih-Cheng; Ma, Zheng

    2012-01-01

    of presenting the organizational innovation process: two-way interactive triggers for organizational innovation integrating three levels – individual, group and organization, and three tails of organizational innovation process. By exploring the organizational innovation process, this study has extended...... and organizations. More importantly, these three tails are not isolated but integrated - this can be viewed as three stages for organizational innovation process.......Several prior articles have emphasized the importance of organizational innovation and change. To advance our understanding, this paper seeks to address the following question: “in what ways the outcome of organizational innovation process distributed over time” by examining organizational...

  8. 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

  9. Removal of 226Ra from tailings pond effluents and stabilization of uranium mine tailings. Bench and pilot scale studies

    International Nuclear Information System (INIS)

    Schmidtke, N.W.; Averill, D.; Bryant, D.N.; Wilkinson, P.; Schmidt, J.W.

    1978-01-01

    Increased world demand for uranium has resulted in recent expansion of Canadian uranium mining operations. Problems have been identified with the discharge of radionuclides such as 226 Ra from tailings pond effluents and with the stabilization of mine tailings. At Environment Canada's Wastewater Technology Centre (WTC) two projects were undertaken in cooperation with the Canadian Uranium Mining Industry and other federal government agencies to address these problems. The first project reports on the progress of bench and pilot scale process simulations for the development of a data base for the design of a full scale mechanical physical/chemical 226 Ra removal waste treatment system with an effluent target level of 10 pCi 226 Ra total per litre. The second project addresses problems of the leachability of radionuclides and the stabilization of both uranium mine tailings and BaRaSO 4 sediments from the treatment of acid seepages

  10. Health evaluation of Columbian white-tailed deer on Julia Butler Hansen Refuge for the Columbian white-tailed deer

    Science.gov (United States)

    Creekmore, Terry E.; Glaser, Linda C.

    1999-01-01

    The Columbian white-tailed deer ( Odocoileus virginianus leucurus) was designated an endangered species in 1968. At that time the estimated population along the lower Columbia River of Washington and Oregon was 300 to 400 deer (Gavin, 1984). The Julia Butler Hansen Refuge for the Columbian White-tailed Deer was established in 1972 to protect Columbian white-tailed deer and associated habitat Currently, an estimated 600 deer are present in several separate populations. The total refuge population is estimated at 200 animals. Of those, the mainland population consists of approximately 60 animals while the largest refuge island (Tenasillahe.Island) supports about 120 animals. The remaining 420 deer are present on private lands near the refuge (AI Clark, pers. com.).

  11. Establishing Cynodon dactylon on mining tailings and mining ...

    African Journals Online (AJOL)

    Mining for copper and cobalt generates extensive mounds of removed topsoil and subsoil, and tailings with toxic levels of copper and cobalt. The threat of soil erosion in a high rainfall regime can be countered with rapid establishment of a sod-forming grass, such as Cynodon dactylon, that covers and binds the soil.

  12. Establishing vegetation on Kimberlite mine tailings: 2. Field trials. | N ...

    African Journals Online (AJOL)

    A series of field experiments were carried out on Kimberlite mine tailing located at Cullinan in the Transvaal. The most successful species in pure sward were Chloris gayana, Cynodon aethiopicus, Eragrostis curvula, E. tef, Pennisetum purpureum, Melilotus alban and Medicago sativa. Growth of grasses in the absence of ...

  13. Characterisation of gold tailings dams of the Witwatersrand Basin ...

    African Journals Online (AJOL)

    The oxygen diffusion data reveal that the flow of oxygen in the Witwatersrand tailings dams is controlled by secondary porosity (i.e. cracks caused by roots on the dam surface). The age of the dam does not have a significant bearing on the extent to which the oxidised zone development and subsequently AMD can progress.

  14. High resolution flow field prediction for tail rotor aeroacoustics

    Science.gov (United States)

    Quackenbush, Todd R.; Bliss, Donald B.

    The prediction of tail rotor noise due to the impingement of the main rotor wake poses a significant challenge to current analysis methods in rotorcraft aeroacoustics. This paper describes the development of a new treatment of the tail rotor aerodynamic environment that permits highly accurate resolution of the incident flow field with modest computational effort relative to alternative models. The new approach incorporates an advanced full-span free wake model of the main rotor in a scheme which reconstructs high-resolution flow solutions from preliminary, computationally inexpensive simulations with coarse resolution. The heart of the approach is a novel method for using local velocity correction terms to capture the steep velocity gradients characteristic of the vortex-dominated incident flow. Sample calculations have been undertaken to examine the principal types of interactions between the tail rotor and the main rotor wake and to examine the performance of the new method. The results of these sample problems confirm the success of this approach in capturing the high-resolution flows necessary for analysis of rotor-wake/rotor interactions with dramatically reduced computational cost. Computations of radiated sound are also carried out that explore the role of various portions of the main rotor wake in generating tail rotor noise.

  15. Dominance hierarchy and social grooming in female lion-tailed ...

    Indian Academy of Sciences (India)

    This article reports the structure of dominance and its relationship with social grooming in wild lion-tailed macaque females. The strength of dominance hierarchy was 0.79 on a scale of 0 to 1 indicating a moderate linearity in the ranking system. Dominance scores were converted into an ordinal as well as an interval scale.

  16. Biota of uranium mill tailings near the Black Hills

    Science.gov (United States)

    Mark A. Rumble

    1982-01-01

    Reclamation" often implies the enhancement of the land as wildlife habitat or for other productive uses. However, there are situations where revegetation to stabilize erosion is the only desired goal. Uranium mining and mill sites may fall into this later category. Data pertaining to plant and animal components on revegetated uranium mill tailings was collected....

  17. The price of portfolio selection under tail conditional expectation with ...

    African Journals Online (AJOL)

    One of the ways of managing the risk that can arise from the changes in the relationship between assets and liabilities is by asset-liability management. Recently, Value-at-risk (VaR) and tail conditional expectation (TCE) have also emerged as standard tools for measuring and controlling the risk of trading portfolios.

  18. On robust tail index estimation under random censorship | Sayah ...

    African Journals Online (AJOL)

    type distributions in the framework of randomly censored samples, based on the ideas of Kaplan-Meier integration using the huberized M-estimator of the tail index. We derive their asymptotic results. We illustrate the performance and the ...

  19. Tail asymptotics of the M/G/∞ model

    NARCIS (Netherlands)

    Mandjes, M.; Zuraniewski, P.W.

    2011-01-01

    This paper considers the so-called M/G/∞ model: jobs arrive according to a Poisson process with rate λ, and each of them stays in the system during a random amount of time, distributed as a non-negative random variable B; throughout it is assumed that B is light-tailed. With N(t) denoting the number

  20. Haemorrhagic pseudocyst of the pancreatic tail causing acute ...

    African Journals Online (AJOL)

    Haemorrhagic pseudocyst of the pancreatic tail causing acute abdominal pain in a 12-year-old girl ... Introduction. The acute abdomen in childhood has various aetiologies and represents a leading cause of hospitalization of children [1]. ... The decision was made to manage the patient surgically because of her progressive ...

  1. North European short-tailed breeds of sheep: a review.

    Science.gov (United States)

    Dýrmundsson, O R; Niżnikowski, R

    2010-08-01

    The short-tailed sheep, native of an area stretching from Russia to Iceland, are generally considered a primitive type. These robust northern sheep seem to have been spread by Norse vikings to several countries in this area from the late eighth century to the middle of the eleventh century ad. They have several common characteristics in addition to the fluke-shaped and tapered short tail, such as a wide range of colour patterns, dual-coated wool and the ability to thrive under harsh environmental conditions, often in isolated marginal areas. While 34 short-tailed breeds of North European origin can still be identified, it is clear that their population sizes have declined in most cases and several of them are now rare and endangered. Although these breeds have mainly been confined to certain localities, some of them have gained considerable distribution due to their genetic merits, such as prolificacy. Of these, the Finnsheep and the Romanov are best known being exported to several countries in the world where their genetic material has been utilized through crossbreeding with local sheep. This has resulted in the production of some new synthetic breeds. Meat is now generally the main product of the North European short-tailed breeds and their crossbreds, whereas wool, skins and milk are normally regarded as byproducts, yet of considerable economic importance in some cases. Such breeds have clearly a role to play in sustainable grassland-based production systems in the future.

  2. Bounds for Tail Probabilities of the Sample Variance

    Directory of Open Access Journals (Sweden)

    V. Bentkus

    2009-01-01

    Full Text Available We provide bounds for tail probabilities of the sample variance. The bounds are expressed in terms of Hoeffding functions and are the sharpest known. They are designed having in mind applications in auditing as well as in processing data related to environment.

  3. Faun tail: a rare cutaneous sign of spinal dysraphism.

    Science.gov (United States)

    Kurtipek, Gülcan Saylam; Cihan, Fatma Göksin; Öner, Vefa; Ataseven, Arzu; Özer, İlkay; Akman, Zahide

    2015-01-01

    Faun tail is a triangle-shaped hypertrichosis of the lumbosacral region. It is a rare condition and it can be a cutaneous marker of underlying spinal cord anomaly. We report on a 17-year-old female patient with hypertrichosis on the lumbosacral area since birth that was later diagnosed with tethered cord in magnetic resonance imaging.

  4. Active vertical tail buffeting suppression based on macro fiber composites

    Science.gov (United States)

    Zou, Chengzhe; Li, Bin; Liang, Li; Wang, Wei

    2016-04-01

    Aerodynamic buffet is unsteady airflow exerting forces onto a surface, which can lead to premature fatigue damage of aircraft vertical tail structures, especially for aircrafts with twin vertical tails at high angles of attack. In this work, Macro Fiber Composite (MFC), which can provide strain actuation, was used as the actuator for the buffet-induced vibration control, and the positioning of the MFC patches was led by the strain energy distribution on the vertical tail. Positive Position Feedback (PPF) control algorithm has been widely used for its robustness and simplicity in practice, and consequently it was developed to suppress the buffet responses of first bending and torsional mode of vertical tail. However, its performance is usually attenuated by the phase contributions from non-collocated sensor/actuator configuration and plants. The phase lag between the input and output signals of the control system was identified experimentally, and the phase compensation was considered in the PPF control algorithm. The simulation results of the amplitude frequency of the closed-loop system showed that the buffet response was alleviated notably around the concerned bandwidth. Then the wind tunnel experiment was conducted to verify the effectiveness of MFC actuators and compensated PPF, and the Root Mean Square (RMS) of the acceleration response was reduced 43.4%, 28.4% and 39.5%, respectively, under three different buffeting conditions.

  5. Ecosystem recovery analysis of mine tailings at Mhangura copper ...

    African Journals Online (AJOL)

    Remote sensing techniques are increasingly being employed in monitoring environmental change. Vegetation indices such as normalised difference vegetation index (NDVI), are useful in estimating primary production, an important component of ecosystem function. The success of rehabilitation on mine tailings may be ...

  6. Do different subspecies of Black-tailed Godwit

    NARCIS (Netherlands)

    Lopes, R.J.; Alves, J.A.; Gill, J.A.; Gunnarsson, T.G.; Hooijmeijer, J.C.E.W.; Lourenço, P.M.; Masero, J.A.; Piersma, T.; Potts, P.M.; Rabaçal, B.; Reis, S.; Sánchez-Guzmán, J.M.; Santiago-Quesada, F.; Villegas, A.

    2013-01-01

    Resolving the migratory connectivity (identifying non-breeding grounds) of migrating bird populations that are morphologically similar is crucial for an understanding of their population dynamics and ultimately their conservation. Such is the case in Black-tailed Godwits Limosa limosa, where the

  7. Tail asymptotics for dependent subexponential differences

    DEFF Research Database (Denmark)

    Albrecher, H; Asmussen, Søren; Kortschak, D.

    We study the asymptotic behavior of P(X − Y > u) as u → ∞, where X is subexponential and X, Y are positive random variables that may be dependent. We give criteria under which the subtraction of Y does not change the tail behavior of X. It is also studied under which conditions the comonotonic co...

  8. Effect of surface treatment of tailings on effluent quality

    International Nuclear Information System (INIS)

    Murray, D.R.

    1980-01-01

    Successful reclamation treatment, in preparation for long range abandonment of mining wastes, involves both surface treatment and water quality control containment of waste solids and liquid contaminants. This paper describes use of lysimeters containing 125 tonnes of tailings to determine the impact of gravel, sawdust, and vegetation as surface treatments on the quality and quantity of effluent produced from sulphide-containing uranium mill tailings. Over a five-year period these treatments were observed and compared with bare tailings where no surface addition was made. The treatments did not alter the effluent quality to a level acceptable to regulatory requirements. Surface treatments did not appear to affect the leaching of Ra-226, NH 4 and NO 3 . The concentration of Fe, SO 4 , Cu, Pb, and Al increased with the rise of acidity as the pH changed from pH 9.5 to pH 2 in four and one-half years. However the rate and extent of changes of some of these parameters vary with the treatment. The experimental results for the observed trends are presented with limited explanation. Original design problems and unexpected delays in tailing reactions have made firm conclusions impossible at this stage. These data, however, provide a base for further investigation and development of explanations and firm conclusions, as to the role of surface treatment in long-term waste abandonment

  9. Studies on Arsenic Release and its Mitigation from Tailings Dam ...

    African Journals Online (AJOL)

    user

    dispersive spectroscopy (SEM-EDX). Polished mounts (< 45 µm) with average diameters and thickness of 3 cm and 1 cm respectively were prepared with the tailings material using conducting graphite doped epoxy. This was then carbon coated for the SEM-EDX analysis in order to prevent elec- tron build up on the sample ...

  10. 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 ...

  11. Survival of white-tailed deer neonates in Louisiana

    Science.gov (United States)

    Rebecca M. Shuman; Michael J. Cherry; Taylor N. Simoneaux; Elizabeth A. Dutoit; John C. Kilgo; Michael J. Chamberlain; Karl V. Miller

    2017-01-01

    Changing predator communities have potential to complicate management focused on ensuring sustainable white-tailed deer (Odocoileus virginianus) populations. Recent research reported that predation on neonates by coyotes (Canis latrans) and bobcats (Lynx rufus) can limit recruitment. However, no research has been conducted in areas of the southeastern United States...

  12. The utilization of forward osmosis for coal tailings dewatering

    Science.gov (United States)

    The feasibility of dewatering coal tailings slurry by forward osmosis (FO) membrane process was investigated in this research. A prototype cell was designed and used for the dewatering tests. A cellulosic FO membrane (Hydration Technology Innovations, LLC, Albany, OR) was used fo...

  13. Electrodialytic remediation of copper mine tailings: Comparing different operational conditions

    DEFF Research Database (Denmark)

    Rojo, Adrian; Hansen, Henrik K.; Ottosen, Lisbeth M.

    2006-01-01

    This work compares and evaluates sixteen electrodialytic laboratory remediation experiments on copper mine tailings. Different parameters were analyzed, such as remediation time, voltage drop, addition of desorbing agents, and the use of pulsed electrical fields. The results show that electric cu...

  14. Architecture and environmental restoration: Remediating uranium mill tailings from buildings

    International Nuclear Information System (INIS)

    Teply, J.D.

    1991-01-01

    The US Department of Energy (DOE) Grand Junction Projects Office (GJPO) manages the Uranium Mill Tailings Remedial Action (UMTRA) Program in Grand Junction, Colorado. This program is a congressionally mandated clean up of by-product waste that resulted from the extraction of yellow cake from uranium ore. The by-product waste, a fine sand commonly called open-quotes mill tailingclose quotes is contaminated with low-level radioactivity. These mill tailings were available to the community for use as construction material from approximately 1952 to 1966; their use as bedding material for concrete slabs, utilities, backfill materials, concrete sand, and mortar created unique remediation problems that required innovative solutions. This paper describes how design personnel approach the remediation of structures, the evaluation of the buildings, and the factors that must be considered in completing the remediation design. This paper will not address the health risks of the tailings in an inhabited space, the remediation of exterior areas, or the process of determining where the tailings exist in the building

  15. Uranium mine tailings and obligations to future generations

    International Nuclear Information System (INIS)

    Brook, A.

    1980-01-01

    Low-level wastes from uranium mine/mill operations, because of their huge volume, are a serious problem, yet relatively little attention has been paid to them. Management of tailings piles and waste liquids in the short term is fairly effective. However these management techniques involve continuous, active treatment of the wastes, which may not continue after operations shut down, and rely on containment structures with a short effective life. Tailings can probably be rendered safe for future generations if sufficient resources are devoted to the task. The central moral question is whether we are obligated to assume the costs of tailings management, or whether it is permissible to pass them on to future generations. The basic moral principle that each person has the same value as any other implies that the generation that reaps the benefits of nuclear power must assume the costs of managing mine tailings and not discriminate in favour of one group of persons, our own generation. The argument that people who may exist in the future have intrinsically less value than people currently alive is not accepted by the author. The methodology for determining obligations to future generations which has been applied to mine/mill wastes could be applied to other nuclear issues, too. (LL)

  16. Cleaning up commingled uranium mill tailings: is Federal assistance necessary

    International Nuclear Information System (INIS)

    1979-01-01

    GAO was asked to determine whether Federal assistance should be given to operating mill owners that have processed uranium for sale to both government and industry and, thus, generated residual radioactive wastes. The wastes generated for both government and commercial use are called commingled uranium mill tailings. GAO recommends that the Congress provide assistance to active mill owners to share in the cost of cleaning up that portion of the tailings which were produced under Federal contract. Further, GAO believes that the Congress should also consider having the Federal government assist those mills who acted in good faith in meeting all legal requirements pertaining to controlling the mill tailings that were generated for commercial purposes and for which the Federal government is now requiring retroactive remedial action. At the same time, the Congress should make sure that this action establishes no precedent for the Federal government assuming the financial responsibility of cleaning up other non-Federal nuclear facilities and wastes, including those mill tailings generated after the date when the Federal government notified industry that the failings should be controlled

  17. Bias-corrected estimation of stable tail dependence function

    DEFF Research Database (Denmark)

    Beirlant, Jan; Escobar-Bach, Mikael; Goegebeur, Yuri

    2016-01-01

    We consider the estimation of the stable tail dependence function. We propose a bias-corrected estimator and we establish its asymptotic behaviour under suitable assumptions. The finite sample performance of the proposed estimator is evaluated by means of an extensive simulation study where...

  18. Reading Confidence with "Tail Waggin' Tutors"

    Science.gov (United States)

    Loveridge, Stacy

    2017-01-01

    This report discusses the benefits of canine-assisted reading through the "Tail Waggin' Tutors" program at the Glen Burnie Regional Library in Anne Arundel County, Maryland. Presented are the two different types of therapy dog interactions, Animal-Assisted Therapy (AAT) and Animal-Assisted Activities (AAA). The first canine-assisted…

  19. Identification of geobacter populations in the uranium mill tailings Shiprock

    International Nuclear Information System (INIS)

    Radeva, G.; Selenska-Pobell, S.

    2006-01-01

    Geobacter - specific primers were used for construction of a 16S rDNA library for a water sample collected from uranium mill tailings near Shiprock (Sh853) in the USA . Most of the retrieved sequences were affiliated with different Geobacter species, however sequences related to other δ -Proteobacteria were identified as well. (authors)

  20. One-Tube Isolation of DNA from Mouse Tails.

    Science.gov (United States)

    Green, Michael R; Sambrook, Joseph

    2018-02-01

    This protocol describes a variation of a simple method for isolation of DNA from mouse tails that uses commercially available gel-barrier tubes to eliminate the tedious transfer of samples during serial extractions with organic solvents. This variant is useful when processing very large numbers of samples. © 2018 Cold Spring Harbor Laboratory Press.

  1. Genetic variations between indigenous fat-tailed sheep populations

    African Journals Online (AJOL)

    ONOS

    2010-09-06

    Sep 6, 2010 ... 2Department of Animal Science, faculty of agriculture, University of Arak, Arak, Iran. . Accepted 10 May, 2010. Blood samples were collected from a total 816 sheep of both sexes in three Iranian fat-tailed breeds. (Sangsari, Makoei, indigenous sheep on firoozkouh mountain) serum, plasma and erythrocyte ...

  2. Dominance hierarchy and social grooming in female lion-tailed ...

    Indian Academy of Sciences (India)

    Madhu

    This article reports the structure of dominance and its relationship with social grooming in wild lion-tailed macaque females. The strength of dominance hierarchy ... study of social organization (Thierry et al 2004). A key factor that helps understand social organization is the dominance relationships among individuals of a ...

  3. Long memory and tail dependence in trading volume and volatility

    DEFF Research Database (Denmark)

    Rossi, Eduardo; Santucci de Magistris, Paolo

    2013-01-01

    We investigate the relationship between volatility, measured by realized volatility, and trading volume for 25 NYSE stocks. We show that volume and volatility are long memory but not fractionally cointegrated in most cases. We also find right tail dependence in the volatility and volume innovations...

  4. The evolutionary strata of DARPP-32 tail implicates hierarchical ...

    Indian Academy of Sciences (India)

    The evolutionary strata of DARPP-32 tail implicates hierarchical functional expansion in higher vertebrates. CHOONG YONG UNG and TEOW CHONG TEOH. Supplementary data 1. Protein sequences of PPP1R1 family from 39 vertebrate species in FASTA format. Supplementary data 2. Multiple sequence alignment results ...

  5. Diseases of white-tailed deer. Chapter 5. Neoplasia

    Energy Technology Data Exchange (ETDEWEB)

    Cosgrove, G. E.; Satterfield, L. D.; Nettles, V. F.

    1977-01-01

    Data on the occurrence and etiology of neoplasms in native populations of white-tailed deer are reviewed. Cutaneous fibromas, non-progressive lesions considered to be of viral etiology, are discussed in detail. The clinical signs associated with other benign and malignant neoplasms are discussed briefly. 30 references.

  6. Treatment of Iron Tailings at the Forecariah Guinea Mine - Guinea ...

    African Journals Online (AJOL)

    Michael

    2016-06-01

    Jun 1, 2016 ... Kali, A. and Buah, W. K. (2016), “Treatment of Iron Tailings at the Forecariah Guinea Mine - Guinea ... subsidiary of Bellzone Australia, mines and export .... of water. Chemical analysis of the feed, magnetics and non-magnetics samples generated from the test work was performed using XRF. A number of ...

  7. A tail bound for read-k families of functions

    Czech Academy of Sciences Publication Activity Database

    Gavinsky, Dmitry; Lovett, S.; Saks, M.; Srinivasan, S.

    2015-01-01

    Roč. 47, č. 1 (2015), s. 99-108 ISSN 1042-9832 Institutional support: RVO:67985840 Keywords : tail bound * deviation bound * random variables Subject RIV: BA - General Mathematics Impact factor: 1.011, year: 2015 http://onlinelibrary.wiley.com/doi/10.1002/rsa.20532/abstract

  8. 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.

  9. FINAL TAILINGS OF METAL-WORKING PRODUCTION. Part 3. PHYSICO-MECHANICAL CHARACTERISTICS

    Directory of Open Access Journals (Sweden)

    O. M. Djakonov

    2011-01-01

    Full Text Available The indices of adhesion and friability of metal-containing tailings, their water absorbency and wettability and also abrasive characteristics of tailings with the purpose of prevention of contacting surfaces wear are studied.

  10. Preliminary results on tail energetics in the Moorish gecko, Tarentola mauritanica

    Directory of Open Access Journals (Sweden)

    Tommaso Cencetti

    2011-06-01

    Full Text Available The amount of lipids, proteins, ashes and water in original versus regenerated tails in Tarentola mauritanica shows differences, especially on the lipid fraction, supporting adaptive function hypotheses during reproduction of regenerated tails in geckos.

  11. 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

  12. 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.

  13. 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

  14. Condition-dependence of Defensive Tail Displays in Common Garter Snakes (Thamnophis sirtalis)

    OpenAIRE

    Anderson, Sabrina Shay A.; Hudson, Spencer B.; Neuman-Lee, Lori; French, Susannah S.

    2017-01-01

    Individual snakes can exhibit a diversity of antipredator responses including crypsis, flight, and a variety of stereotyped behavioral reactions to predators at close range. Among these responses are behavioral differences in the movement (e.g., waving or wiggling) of a conspicuous tail by an otherwise cryptically colored snake. Defensive tail displays may disorient a predator, divert attack to the tail, act as a warning signal, or serve no function at all. The use of tail displays in snakes ...

  15. 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.

  16. 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

  17. 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

  18. The Pricing of Tail Risk and the Equity Premium: Evidence from International Option Markets

    DEFF Research Database (Denmark)

    Andersen, Torben Gustav; Fusari, Nicola; Todorov, Viktor

    We explore the pricing of tail risk as manifest in index options across international equity markets. The risk premium associated with negative tail events displays persistent shifts, unrelated to volatility. This tail risk premium is a potent predictor of future equity returns, while option......, suggesting a high degree of integration among the major global equity markets....

  19. On The Left Tail-End Probabilities and the Probability Generating ...

    African Journals Online (AJOL)

    On The Left Tail-End Probabilities and the Probability Generating Function. ... Journal of the Nigerian Association of Mathematical Physics ... In this paper, another tail-end probability function is proposed using the left tail-end probabilities, p( ≤ i ) = Πṙ The resulting function, πx(t), is continuous and converges uniformly ...

  20. Human born with a tail: A case report | Sarmast | South African ...

    African Journals Online (AJOL)

    Context. e dorsal cutaneous appendage, or so-called human tail, is often considered to be a cutaneous marker of underlying occult spinal dysraphism. Human tails have always elicited curiosity. A unique case of human dysraphism is described. Case report. An interesting case of a child with a tail-like caudal appendage ...