Heavy metals in soil on spoil heap of an abandoned lead ore ...

African Journals Online (AJOL)

EJIRO

(Ti, Fe and Al) of a soil profile on spoil heap were examined. 54 soil samples were .... move gravel and rocks, put in plastic bags then sent to the Service. Central du ..... micro- organisms and microbial processes in agricultural soils. A review.

Volume reducing and modifying of neutralized sludge from acid waste water treatment of uranium ore heap leaching

International Nuclear Information System (INIS)

Zhong Pingru; Ding Tongsen; Gu Jianghan

1997-01-01

A process is worked out on the basis of traditional lime neutralization, viz. acid waste water from uranium ore heap leaching is treated by limestone and lime double neutralizing-sludge recycling. First, the waste water is reacted with cheaper limestone to precipitate some metal ions, such as Fe and Al, which form hydroxides at lower pH, and neutralize strong acid, then neutralized with lime to required pH value. The formed precipitate as sludge is steadily recycled in the process. The principal advantage of the process over lime neutralization process is that reagent cost saved by 1/3 and formed sludge volume decreased by 2/3. Besides, the performances of sludge filtrating and settling are improved. The mechanism of sludge volume reducing and modification is also investigated

Polonium (210Po) and uranium (234U, 238U) in water, phosphogypsum and their bioaccumulation in plants around phosphogypsum waste heap at Wislinka (nothern Poland)

International Nuclear Information System (INIS)

Skwarzec, B.; Borylo, A.; Kosinska, A.; Radzajewska, S.

2010-01-01

The principal sources of polonium and uranium radionuclides the Wislinka area waste dump are phosphorites and phosphogypsum produced by the Phosphoric Fertilizers Industry of Gdansk. The values of uranium and polonium concentration in water with immediate surroundings of waste heap are considerably higher than in the waters of the Martwa Wisla river. The activity ratio 234 U/ 238 U is approximately about one in the phosphogypsum (0.97±0.06 and 0.99±0.04) and in the water of a retention reservoir and a pumping station (0.92±0.01 and 0.99±0.04), while in the water from the Martwa Wisla river is slightly higher than one (1.00±0.07 and 1.06±0.02). The leaching process of uranium and polonium from the phosphogypsum waste heap is responsible for the maximum uranium concentration (1097±6 μg·dm -3 and 1177±6 μg·dm -3 ) and the high 210 Po concentration (131.4±0.9 mBq·dm -3 and 165.7±1.4 mBq·dm -3 ) in the retention reservoir. The major source of polonium and uranium in plants are wet and dry atmospheric falls gathering soil and air dust from the phosphogypsum waste dump and root system. The highest uranium and polonium concentrations were found in older part of grasses (yellow oatgrass, meadow foxtail, moneywort), exposed to atmospheric falls for a long time. The maximum concentrations of 210 Po were characterized for samples of plant root collected at the retention reservoir (150.50±4.97 and 108.55±3.95 Bq·kg -1 dry mass). Polonium and uranium concentrations in water samples of the Martwa Wisla river are relatively low in comparison with the value in the retention reservoir and pumping station near the phosphogypsum waste heap. This suggests that the radionuclides could be leached from the dumping site to the surrounding environment. (authors)

Information base for waste repository design. Volume 3. Waste/rock interactions

International Nuclear Information System (INIS)

Koplick, C.M.; Pentz, D.L.; Oston, S.G.; Talbot, R.

1979-01-01

This report describes the important effects resulting from interaction between radioactive waste and the rock in a nuclear waste repository. The state of the art in predicting waste/rock interactions is summarized. Where possible, independent numerical calculations have been performed. Recommendations are made pointing out areas which require additional research

Two-tier relaxed heaps

DEFF Research Database (Denmark)

Elmasry, Amr; Jensen, Claus; Katajainen, Jyrki

2008-01-01

We introduce a data structure which provides efficient heap operations with respect to the number of element comparisons performed. Let n denote the size of the heap being manipulated. Our data structure guarantees the worst-case cost of O(1) for finding the minimum, inserting an element, extract...

Rock mechanics activities at the Waste Isolation Pilot Plant

International Nuclear Information System (INIS)

Francke, C.; Saeb, S.

1996-01-01

The application of rock mechanics at nuclear waste repositories is a true multidisciplinary effort. A description and historical summary of the Waste Isolation Pilot Plant (WIPP) is presented. Rock mechanics programs at the WIPP are outlined, and the current rock mechanics modeling philosophy of the Westinghouse Waste Isolation Division is discussed

Disposal of radioactive waste in Swedish crystalline rocks

International Nuclear Information System (INIS)

Greis Dahlberg, Christina; Wikberg, Peter

2015-01-01

SKB, Swedish Nuclear Fuel and Waste Management Company is tasked with managing Swedish nuclear and radioactive waste. Crystalline rock is the obvious alternative for deep geological disposal in Sweden. SKB is, since 1988, operating a near surface repository for short-lived low and intermediate-level waste, SFR. The waste in SFR comprises operational and decommissioning waste from nuclear plants, industrial waste, research-related waste and medical waste. Spent nuclear fuel is currently stored in an interim facility while waiting for a license to construct a deep geological repository. The Swedish long-lived low and intermediate-level waste consists mainly of BWR control rods, reactor internals and legacy waste from early research in the Swedish nuclear programs. The current plan is to dispose of this waste in a separate deep geological repository, SFL, sometimes after 2045. Understanding of the rock properties is the basis for the design of the repository concepts. Swedish crystalline rock is mechanical stable and suitable for underground constructions. The Spent Fuel Repository is planned at approximately 500 meters depth in the rock at the Forsmark site. The host rock will keep the spent fuel isolated from human and near-surface environment. The rock will also provide the stable chemical and hydraulic conditions that make it possible to select suitable technical barriers to support the containment provided by the rock. A very long lasting canister is necessary to avoid release and transport of radionuclides through water conducting fractures in the rock. A canister designed for the Swedish rock, consists of a tight, 5 cm thick corrosion barrier of copper and a load-bearing insert of cast iron. To restrict the water flow around the canister and by that prevent fast corrosion, a bentonite buffer will surround the canister. Secondary, the bentonite buffer will retard a potential release by its strong sorption of radionuclides. The SFR repository is situated in

Disposal of radioactive waste in Swedish crystalline rocks

Energy Technology Data Exchange (ETDEWEB)

Greis Dahlberg, Christina; Wikberg, Peter [Svensk Kaernbraenslehantering AB, Stockholm (Sweden)

2015-07-01

SKB, Swedish Nuclear Fuel and Waste Management Company is tasked with managing Swedish nuclear and radioactive waste. Crystalline rock is the obvious alternative for deep geological disposal in Sweden. SKB is, since 1988, operating a near surface repository for short-lived low and intermediate-level waste, SFR. The waste in SFR comprises operational and decommissioning waste from nuclear plants, industrial waste, research-related waste and medical waste. Spent nuclear fuel is currently stored in an interim facility while waiting for a license to construct a deep geological repository. The Swedish long-lived low and intermediate-level waste consists mainly of BWR control rods, reactor internals and legacy waste from early research in the Swedish nuclear programs. The current plan is to dispose of this waste in a separate deep geological repository, SFL, sometimes after 2045. Understanding of the rock properties is the basis for the design of the repository concepts. Swedish crystalline rock is mechanical stable and suitable for underground constructions. The Spent Fuel Repository is planned at approximately 500 meters depth in the rock at the Forsmark site. The host rock will keep the spent fuel isolated from human and near-surface environment. The rock will also provide the stable chemical and hydraulic conditions that make it possible to select suitable technical barriers to support the containment provided by the rock. A very long lasting canister is necessary to avoid release and transport of radionuclides through water conducting fractures in the rock. A canister designed for the Swedish rock, consists of a tight, 5 cm thick corrosion barrier of copper and a load-bearing insert of cast iron. To restrict the water flow around the canister and by that prevent fast corrosion, a bentonite buffer will surround the canister. Secondary, the bentonite buffer will retard a potential release by its strong sorption of radionuclides. The SFR repository is situated in

Bioaccumulation of polonium ({sup 210}Po) and uranium ({sup 234}U, {sup 238}U) in plants around phosphogypsum waste heap in Wislinka (northern Poland)

Energy Technology Data Exchange (ETDEWEB)

Borylo, A.; Skwarzec, B. [Gdansk Univ. (Poland). Faculty of Chemistry

2011-07-01

In the study the activities of polonium {sup 210}Po and uranium {sup 234}U, {sup 238}U in plants, collected near phosphogypsum waste heap in Wis'linka (northern Poland), were determined by using the alpha spectrometry. The obtained results revealed that the concentrations of {sup 210}Po, {sup 234}U, and {sup 238}U in the analyzed plants were differentiated. In the analyzed flora organisms the highest amounts of polonium and uranium were found in ruderal plant samples as well as willow samples (Salix viminalis) from protection zone of phosphogypsum waste heap. The concentrations of {sup 210}Po, {sup 234}U and {sup 238}U in the analyzed plants were higher in roots than in green parts of plants. The higher concentrations of {sup 210}Po and {sup 238}U radionuclides were estimated for hydrophyte (common sedge Carex nigra Reichard), the favourite habitat of which is particularly wet meadow and for plants collected in the vicinity of phosphogypsum waste heap. The major source of polonium and uranium in analyzed plants is root system. The values of {sup 234}U/ {sup 238}U activity ratio in all analyzed plants are closed to one, what indicated that source of uranium in analyzed plants is phosphogypsum. The highest uranium and polonium concentrations were characterized for plants, which are covered with tomentose. The comparability polonium and uranium contents were confirmed in edible plants, but higher accumulation was determined in ripe species than immature species of vegetables. The higher polonium and uranium concentrations were noticed in green parts of plant, the lower in roots. Polonium concentration in cultivated plants samples was not species diverse. Therefore, the significant source of polonium and uranium in analyzed plants is wet and dry atmospheric falls gathering the soil and air dust from phosphogypsum waste dump. The maximum {sup 210}Po and {sup 238}U radionuclides concentrations were found in green parts of red beet (Beta vulgaris esculenta), the

Modeling of nuclear waste disposal by rock melting

International Nuclear Information System (INIS)

Heuze, F.E.

1982-04-01

Today, the favored option for disposal of high-level nuclear wastes is their burial in mined caverns. As an alternative, the concept of deep disposal by rock melting (DRM) also has received some attention. DRM entails the injection of waste, in a cavity or borehole, 2 to 3 kilometers down in the earth crust. Granitic rocks are the prime candidate medium. The high thermal loading initially will melt the rock surrounding the waste. Following resolidification, a rock/waste matrix is formed, which should provide isolation for many years. The complex thermal, mechanical, and hydraulic aspects of DRM can be studied best by means of numerical models. The models must accommodate the coupling of the physical processes involved, and the temperature dependency of the granite properties, some of which are subject to abrupt discontinuities, during α-β phase transition and melting. This paper outlines a strategy for such complex modeling

Waste package performance in unsaturated rock

International Nuclear Information System (INIS)

Pigford, T.H.; Lee, W.W.-L.

1989-03-01

The unsaturated rock and near-atmospheric pressure of the potential nuclear waste repository at Yucca Mountain present new problems of predicting waste package performance. In this paper we present some illustrations of predictions of waste package performance and discuss important data needs. 11 refs., 9 figs., 1 tab

Analysis on one underground nuclear waste repository rock mass in USA

International Nuclear Information System (INIS)

Ha Qiuling; Zhang Tiantian

2012-01-01

When analyzing the rock mass of a underground nuclear waste repository, the current studies are all based on the loading mechanical condition, and the unloading damage of rock mass is unconsidered. According to the different mechanical condition of actual engineering rock mass of loading and unloading, this paper implements a comprehensive analysis on the rock mass deformation of underground nuclear waste repository through the combination of present loading and unloading rock mass mechanics. It is found that the results of comprehensive analysis and actual measured data on the rock mass deformation of underground nuclear waste repository are basically the same, which provide supporting data for the underground nuclear waste repository. (authors)

Waste-rock interactions and bedrock reactions

International Nuclear Information System (INIS)

White, W.B.

1977-01-01

The experimental program is designed to discover possible reactions between shale repository rocks and radioactive wastes. The canister can be regarded in three ways: (a) As a source of heat that modifies the mineralogy and therefore the physical properties of the surrounding rock (dry heat). (b) As a source of heat that activates reactions between minerals in the surrounding rock and slowly percolating ground water. (c) As a source of reaction materials of different composition from the surrounding rock and which therefore may react to form completely new ''minerals'' in a contact aureole around the canister. The matrix of interactions contains two composition axes. The waste compositions are defined by the various prototype waste forms usually investigated: glass, calcine, ''spent fuel'' and the ceramic supercalcine. The temperatures and pressures at which these reactions take place must be investigated. Thus each node on the ''wiring diagram'' is itself a matrix of experiments in which the T and to some extent P are varied. Experiments at higher pressure and temperature allow reactions to take place on a laboratory time scale and thus identify what could happen. These reactions are then followed downward in temperature to determine both phase boundaries and kinetic cut-offs below which equilibrium cannot be achieved on a laboratory time scale

Application of Reactive Transport Modeling to Heap Bioleaching of Copper

Science.gov (United States)

Liu, W.

2017-12-01

Copper heap bioleaching is a complex industrial process that utilizes oxidative chemical leaching and microbial activities to extract copper from packed ore beds. Mathematical modelling is an effective tool for identifying key factors that determine the leaching performance. HeapSim is a modelling tool that incorporates all fundamental processes that occur in a heap under leach, such as the movement of leaching solution, chemical reaction kinetics, heat transfer, and microbial activities, to predict the leaching behavior of a heap. In this study, the HeapSim model was applied to simulate chalcocite heap bioleaching at Quebrada Blanca mine located in the Northern Chile. The main findings were that the model could be satisfactorily calibrated and validated to simulate chalcocite leaching. Heap temperature was sensitive to the changes in the raffinate temperature, raffinate flow rate, and the extent of pyrite oxidation. At high flow rates, heap temperature was controlled by the raffinate temperature. In contrast, heat removal by the raffinate solution flow was insignificant at low flow rates, leading to the accumulation of heat generated by pyrite reaction and therefore an increase in heap temperature.

Wagner’s theory of generalised heaps

CERN Document Server

Hollings, Christopher D

2017-01-01

The theories of V. V. Wagner (1908-1981) on abstractions of systems of binary relations are presented here within their historical and mathematical contexts. This book contains the first translation from Russian into English of a selection of Wagner’s papers, the ideas of which are connected to present-day mathematical research. Along with a translation of Wagner’s main work in this area, his 1953 paper ‘Theory of generalised heaps and generalised groups,’ the book also includes translations of three short precursor articles that provide additional context for his major work. Researchers and students interested in both algebra (in particular, heaps, semiheaps, generalised heaps, semigroups, and groups) and differential geometry will benefit from the techniques offered by these translations, owing to the natural connections between generalised heaps and generalised groups, and the role played by these concepts in differential geometry. This book gives examples from present-day mathematics where ideas r...

Mine waste acidic potential and distribution of antimony and arsenic in waters of the Xikuangshan mine, China

International Nuclear Information System (INIS)

Zhou, Jianwei; Nyirenda, Mathews T.; Xie, Lina; Li, Yi; Zhou, Baolong; Zhu, Yue; Liu, Huilin

2017-01-01

The Xikuangshan (XKS) mine in China has vast quantities of waste material and reported antimony (Sb) and arsenic (As) contamination of water in the mine area. This study estimated the potential of acid mine drainage (AMD) generation by waste material at XKS mine by using paste pH, acid base accounting and net acid generation geochemical static tests. Distribution of Sb and As in surface and groundwater in relation to mine waste AMD producing potential was also investigated. Thirty four (34) water samples and representative samples of three mine wastes from different periods (fresh, 10 and 50 years) were collected for this study: waste rock, smelting slag and tailings. The AMD prediction shows that waste rock (from 10 year period) is acid producing while the fresh mine waste had alkaline paste pH indicating the presence of reactive carbonates. Hence AMD generation may have occurred after a long time due to dissolution of carbonates. Water analysis found Sb with higher concentration than As with means of 3.74 mg/L and 0.19 mg/L respectively. Highest Sb and As concentrations were observed in the North mine along the water flow path from waste heaps and tailing pond; Mine water in the South mine also had elevated Sb and As concentrations. Mining activities at the XKS mine have accelerated Sb and As releases because of the disturbed natural equilibrium. Proper mine waste management and collection and treatment of outflow from the waste rock heaps and tailing ponds seem to be a promising mitigation options. - Highlights: • High levels of Sb and As were detected in alkaline water at Xikuangshan mine. • Static test showed that mine waste aged over 10 years was acid generating. • Mine waste influenced the high concentration of Sb and As in water. • The Sb/As ratios in water favored Sb because of high Sb content in the ore body.

United States National Waste Terminal Storage argillaceous rock studies

International Nuclear Information System (INIS)

Brunton, G.D.

1981-01-01

The past and present argillaceous rock studies for the US National Waste Terminal Storage Program consist of: (1) evaluation of the geological characteristics of several widespread argillaceous formations in the United States; (2) laboratory studies of the physical and chemical properties of selected argillaceous rock samples; and (3) two full-scale in situ surface heater experiments that simulate the emplacement of heat-generating radioactive waste in argillaceous rock

United States National Waste Terminal Storage argillaceous rock studies

International Nuclear Information System (INIS)

Brunton, G.D.

1979-01-01

The past and present argillaceous rock studies for the US National Waste Terminal Storage Program consist of: (1) evaluation of the geological characteristics of several widespread argillaceous formations in the United States; (2) laboratory studies of the physical and chemical properties of selected argillaceous rock samples; and (3) two full-scale in-situ surface heater experiments that simulate the emplacement of heat-generating radioactive waste in argillaceous rock

Waste-rock interactions in the immediate repository

International Nuclear Information System (INIS)

McCarthy, G.J.

1977-01-01

The high level wastes (HLW's) to be placed underground in rock formations will contain significant amounts of radioactive decay heat for the first hundred-or-so years of isolation. Several physical-chemical changes analogous to natural geochemical processes can occur during this ''thermal period.'' The waste canister can act as a heat source and cause changes in the mineralogy and properties of the surrounding rocks. Geochemically, this is ''contact metamorphism.'' In the event that the canister is corroded and breached, chemical reactions can occur between the HLW, the surrounding rock and possibly the remains of the canister. In a dry repository which has not been backfilled (and thus pressurized) these interactions could be slow at best and with rates decreasing rapidly as the HLW cools. However, significant interactions can occur in years, months or even days under hydrothermal conditions. These conditions could be created by the combination of HLW heat, overburden pressure and water mobilized from the rocks or derived from groundwater intrusion. At the end of the thermal period these interaction products would constitute the actual HLW form (or ''source term'') subject to the low temperature leaching and migration processes under investigation in other laboratories. It is quite possible that these interaction product waste forms will have superior properties compared to the original HLW. Experimental programs initiated at Penn State during the last year aim at determining the nature of any chemical or mineralogical changes in, or interactions between, HLW solids and host rocks under various repository ambients. The accompanying figures describe the simulated HLW forms and the experimental approach and techniques. Studies with basalts as the repository rock are supported by Rockwell Hanford Operations and with shales by the Office of Waste Isolation

Interacting via the Heap in the Presence of Recursion

Directory of Open Access Journals (Sweden)

Jurriaan Rot

2012-12-01

Full Text Available Almost all modern imperative programming languages include operations for dynamically manipulating the heap, for example by allocating and deallocating objects, and by updating reference fields. In the presence of recursive procedures and local variables the interactions of a program with the heap can become rather complex, as an unbounded number of objects can be allocated either on the call stack using local variables, or, anonymously, on the heap using reference fields. As such a static analysis is, in general, undecidable. In this paper we study the verification of recursive programs with unbounded allocation of objects, in a simple imperative language for heap manipulation. We present an improved semantics for this language, using an abstraction that is precise. For any program with a bounded visible heap, meaning that the number of objects reachable from variables at any point of execution is bounded, this abstraction is a finitary representation of its behaviour, even though an unbounded number of objects can appear in the state. As a consequence, for such programs model checking is decidable. Finally we introduce a specification language for temporal properties of the heap, and discuss model checking these properties against heap-manipulating programs.

Overview of OWI waste/rock interaction studies

International Nuclear Information System (INIS)

Jenks, G.H.

1977-01-01

A review is presented of office of waste isolation (OWI) programs which fall within the waste/rock categories. Discussions are included on salt repository design, thermal powers and radiation intensities, maximum temperatures and gamma doses, salt temperatures around high level waste cannisters, projects concerned with radiation and thermal effects, projects concerned with long term interactions, and waste isolation safety assessment tasks

Heap leaching procedure for the Uranium extraction

International Nuclear Information System (INIS)

Shishahbore, M. R.

2002-01-01

Heap leaching of Uranium ores is currently in use in several countries. Before taking any decision for construction of heap in industrial scale, it is necessary to obtain the main factors that influence the heap leaching process, such as acid construction, acid solution flowrate, temperature of reaction, or size, ration of liquid to solid, permeability and suitable oxidant. To achieve the above parameters, small scale column leaching is usually recommended. In this project column leaching were carried out in 6 plexiglass column with 43.5 cm an height and 7.4 cm inner diameter. In each column closely 2.00 kg Uranium ore were leached by sulfuric acid. Leaching operation on Iranian ores from two different anomalies from the same area were investigated. In this project, six column were leached at different flowrate of eluent and effect of oxidant were investigated. Acid consumption were in the range of 60 - 144 kg per ton ore and recovery between 73.07% - 99.97%. Finally according to the results obtained, investigated that over are suitable to heap leaching technique. Al tough, to enforce of heap leaching project need to more experiments

Model of heap formation in vibrated gravitational suspensions.

Science.gov (United States)

Ebata, Hiroyuki; Sano, Masaki

2015-11-01

In vertically vibrated dense suspensions, several localized structures have been discovered, such as heaps, stable holes, expanding holes, and replicating holes. Because an inclined free fluid surface is difficult to maintain because of gravitational pressure, the mechanism of those structures is not understood intuitively. In this paper, as a candidate for the driving mechanism, we focus on the boundary condition on a solid wall: the slip-nonslip switching boundary condition in synchronization with vertical vibration. By applying the lubrication approximation, we derived the time evolution equation of the fluid thickness from the Oldroyd-B fluid model. In our model we show that the initially flat fluid layer becomes unstable in a subcritical manner, and heaps and convectional flow appear. The obtained results are consistent with those observed experimentally. We also find that heaps climb a slope when the bottom is slightly inclined. We show that viscoelasticity enhances heap formation and climbing of a heap on the slope.

Stability Analysis and Stabilization of Miduk Heap Leaching Structure, Iran

Directory of Open Access Journals (Sweden)

Mehdi Amini

2013-06-01

Full Text Available To construct copper heap leaching structures, a stepped heap of ore is placed over an isolated sloping surface and then washed with sulphuric acid. The isolated bed of such a heap consists of some natural and geosynthetic layers. Shear strength parameters between these layers are low, so they form the possible sliding surfaces of the heaps. Economic and environmental considerations call for studying such slides. In this study, firstly, results of the laboratory tests carried on the materials of the heap leaching structures bed are presented. Then, the instability mechanisms of such structures are investigated and proper approaches are summarized for their stabilization. Finally, stability of the Miduk copper heap is evaluated as a case history, and appropriate approaches and their effects are discussed for its stabilization.

Policy-based benchmarking of weak heaps and their relatives

DEFF Research Database (Denmark)

Bruun, Asger; Edelkamp, Stefan; Katajainen, Jyrki

2010-01-01

In this paper we describe an experimental study where we evaluated the practical efficiency of three worst-case efficient priority queues: 1) a weak heap that is a binary tree fulfilling half-heap ordering, 2) a weak queue that is a forest of perfect weak heaps, and 3) a runrelaxed weak queue tha...

RELIABILITY OF TRANSPORTATION SYSTEMS OF ROCK HAPS

Directory of Open Access Journals (Sweden)

A. Stepanov

2009-01-01

Full Text Available The ways of increasing of exploitation reliability of dump trucks with the aim of increasing of effectiveness of exploitation of transportation systems of rock heaps at coal mines.

Microstructural variation of vitrified floor tile incorporated with granitic rock waste

International Nuclear Information System (INIS)

Souza, A.J.; Holanda, J.N.F.

2009-01-01

The ornamental rock industry from Northwest Fluminense generates huge amounts of wastes in the form of a fine powder. These wastes are deposited in nature without any care about environmental degradation, which can cause damage to public health, pollution of the natural water sources, and silted banks of rivers. In addition, they also can to affect the landscape aesthetically. In this work was used a granitic rock waste from Santo Antonio de Padua-RJ. This waste is rich in alkaline oxides, which promote the formation of liquid phase and assist the densification of traditional ceramics. The ceramic bodies with up to 47.5% granitic rock waste were pressed at 50 MPa. The ceramic pieces were fired at 1250 deg C. The evolution of sintered microstructure was evaluated by scanning electron microscopy and X-ray diffraction. The results showed that the granitic rock waste influences significantly the microstructure of the sintered ceramic bodies. (author)

PRINCIPLE ROCK TYPES FOR RADIOACTIVE WASTE REPOSITORIES

Directory of Open Access Journals (Sweden)

Sibila Borojević Šostarić

2012-07-01

Full Text Available Underground geological storage of high- and intermediate/low radioactive waste is aimed to represent a barrier between the surface environment and potentially hazardous radioactive elements. Permeability, behavior against external stresses, chemical reacatibility and absorption are the key geological parameters for the geological storage of radioactive waste. Three principal rock types were discussed and applied to the Dinarides: (1 evaporites in general, (2 shale, and (3 crystalline basement rocks. (1 Within the Dinarides, evaporite formations are located within the central part of a Carbonate platform and are inappropriate for storage. Offshore evaporites are located within diapiric structures of the central and southern part of the Adriatic Sea and are covered by thick Mesozoic to Cenozoic clastic sediment. Under very specific circumstances they can be considered as potential site locations for further investigation for the storage of low/intermediate level radioactive wast e. (2 Thick flysch type formation of shale to phyllite rocks are exposed at the basement units of the Petrova and Trgovska gora regions whereas (3 crystalline magmatic to metamorphic basement is exposed at the Moslavačka Gora and Slavonian Mts. regions. For high-level radioactive waste, basement phyllites and granites may represent the only realistic potential option in the NW Dinarides.

Nitrate release from waste rock dumps in the Elk Valley, British Columbia, Canada.

Science.gov (United States)

Mahmood, Fazilatun N; Barbour, S Lee; Kennedy, C; Hendry, M Jim

2017-12-15

The origin, distribution and leaching of nitrate (NO 3 - ) from coal waste rock dumps in the Elk Valley, British Columbia, Canada were defined using chemical and NO 3 - isotope analyses (δ 15 N- and δ 18 O-NO 3 - ) of solids samples of pre- and post-blast waste rock and from thick (up to 180m) unsaturated waste rock dump profiles constructed between 1982 and 2012 as well as water samples collected from a rock drain located at the base of one dump and effluent from humidity cell (HC) and leach pad (LP) tests on waste rock. δ 15 N- and δ 18 O-NO 3 - values and NO 3 - concentrations of waste rock and rock drain waters confirmed the source of NO 3 - in the waste rock to be explosives and that limited to no denitrification occurs in the dump. The average mass of N released during blasting was estimated to be about 3-6% of the N in the explosives. NO 3 - concentrations in the fresh-blast waste rock and recently placed waste rock used for the HC and LP experiments were highly variable, ranging from below detection to 241mg/kg. The mean and median concentrations of these samples ranged from 10-30mg/kg. In this range of concentrations, the initial aqueous concentration of fresh-blasted waste rock could range from approximately 200-600mg NO 3 - -N/L. Flushing of NO 3 - from the HCs, LPs and a deep field profile was simulated using a scale dependent leaching efficiency (f) where f ranged from 5-15% for HCs, to 35-80% for the LPs, to 80-90% for the field profile. Our findings show aqueous phase NO 3 - from blasting residuals is present at highly variable initial concentrations in waste rock and the majority of this NO 3 - (>75%) should be flushed by recharging water during displacement of the first stored water volume. Copyright © 2017 Elsevier B.V. All rights reserved.

Rock solid: the geology of nuclear waste disposal

International Nuclear Information System (INIS)

Reid, Elspeth.

1990-01-01

With a number of nuclear submarines and power stations due to be decommissioned in the next decade, stores of radioactive waste, and arguments about storage increase. Whatever the direction taken by the nuclear industry in Britain, the legacy of waste remains for the foreseeable future. Geology is at the heart of the safety argument for nuclear wastes. It is claimed that rocks should act as the main safety barrier, protecting present and future generations from radiation. Rock Solid presents a clear, accessible and up to date account of the geological problems involved in building a nuclear waste repository. The author describes the geology of some of the possible UK repository sites (Sellafield, Dounreay, Altnabreac, Billingham), explains how sites are investigated (including computer models), and finally considers the crucial question: 'would geological containment of radioactive waste actually work?'. (author)

Particulate Matter and Noise Impact Studies of Waste Rock Dump ...

African Journals Online (AJOL)

Adansi Gold Company Limited identified an economically viable gold deposit at Nkran in the Amansie West District of Ghana. Mining of this deposit requires the disposal of waste rock materials at a proposed waste rock dump near Nkran and Koninase communities. Since particulates and noise emissions from the ...

Acid agglomeration heap leaching: present status, principle and applications

International Nuclear Information System (INIS)

Zeng Yijun

2004-01-01

For extracting valuable metal from clay-bearing acidic ores of poor permeability, agglomerated acid heap leaching appears to be the most effective method, whereas conventional leaching and general heap leaching bring about unsatisfactory recovery and poor economic returns. The present state of research work on acid agglomeration worldwide and its basic principle are discussed. The first commercial application employing acid agglomeration-heap leaching in China is also introduced

Radioactive safety analysis and assessment of waste rock pile site in uranium tailings

International Nuclear Information System (INIS)

Liu Changrong; Liu Zehua; Wang Zhiyong; Zhou Xinghuo

2007-01-01

Based on theoretical calculation and in-situ test results, distribution and emissions of radioactive nuclides of uranium tailings impoundment and waste rock pile sites are analyzed in this paper. It is pointed out that 222 Rn is the main nuclide of uranium tailings impoundment and waste rock pile site. Also 222 Rn is the main source term of public dose. 222 Rn concentrations in the atmospheric environment around and individual dose to Rn gradually decrease with increasing distances to uranium tailings impoundment and waste rock pile site. Based on in-situ tests on five uranium tailings impoundment and waste rock pile sites, a decisive method and safety protection distance are presented, which can be used to guide the validation and design of radioactive safety protection in uranium tailings impoundment and waste rock pile sites. (authors)

Effects of bioleaching on the mechanical and chemical properties of waste rocks

Science.gov (United States)

Yin, Sheng-Hua; Wu, Ai-Xiang; Wang, Shao-Yong; Ai, Chun-Ming

2012-01-01

Bioleaching processes cause dramatic changes in the mechanical and chemical properties of waste rocks, and play an important role in metal recovery and dump stability. This study focused on the characteristics of waste rocks subjected to bioleaching. A series of experiments were conducted to investigate the evolution of rock properties during the bioleaching process. Mechanical behaviors of the leached waste rocks, such as failure patterns, normal stress, shear strength, and cohesion were determined through mechanical tests. The results of SEM imaging show considerable differences in the surface morphology of leached rocks located at different parts of the dump. The mineralogical content of the leached rocks reflects the extent of dissolution and precipitation during bioleaching. The dump porosity and rock size change under the effect of dissolution, precipitation, and clay transportation. The particle size of the leached rocks decreased due to the loss of rock integrity and the conversion of dry precipitation into fine particles.

Hydrological evaluation of five sedimentary rocks for high-level waste disposal

International Nuclear Information System (INIS)

Lomenick, T.F.; Kanehiro, B.Y.

1986-01-01

Utilizing performance criteria that are based upon siting guidelines issued by DOE for postclosure as well as preclosure conditions, a preliminary hydrologic evaluation and ranking is being conducted to determine the suitability of five sedimentary rocks as potential host rocks for a high-level radioactive waste repository. Based upon both quantitative and qualitative considerations, the hydrological ranking of the rocks in order of their potential as a host rock for the disposal of radioactive wastes would be shale, anhydrock, sandstone, chalk, and carbonates, with the first three rocks being significantly better than the remaining two types

Rock mechanics in the National Waste Terminal Storage Program

International Nuclear Information System (INIS)

Monsees, J.E.; Wigley, M.R.

1982-01-01

The overall objective of the rock mechanics program of the Office of Nuclear Waste Isolation is to predict the response of a rock mass hosting a waste repository during its construction, operation, and postoperational phases. The operational phase is expected to be 50 to 100 yr; the postoperational phase will last until the repository no longer poses any potential hazard to the biosphere, a period that may last several thousand years. The rock mechanics program is concerned with near-field effects on mine stability, as well as far-field effects relative to the overall integrity of the geologic waste isolation system. To accomplish these objectives, the rock mechanics program has established interactive studies in numerical simulation, laboratory testing, and field testing. The laboratory and field investigations provide input to the numerical simulations and give an opportunity for verification and validation of the predictive capabilities of the computer codes. Ultimately the computer codes will be used to predict the response of the geologic system to the development of a repository. 3 references, 5 figures

Modeling acid mine drainage in waste rock dumps

Energy Technology Data Exchange (ETDEWEB)

Lefebvre, R. [INRS, Quebec (Canada)

1995-03-01

Acid mine drainage (AMD) results from the oxidation of sulfides present in mine wastes. The acidity generated by these reactions creates conditions under which metals can be leached and represent a threat for surface and ground waters. Even though leachate collection and neutralization are used to treat the problem, the industry is looking for methods to predict and prevent the generation of AMD at new sites and control methods for sites already producing AMD. Waste rock dumps are generally very large accumulations of barren rocks extracted from open pits to access ore bodies. These rocks contain sulfides, most commonly pyrite, and often generate AMD at rates much higher than in mine tailings which are fine grained by-products of milling operations. Numerous coupled physical processes are involved in AMD production in waste rocks. Sulfide oxidation reactions are strongly exothermic and temperatures beyond 70{degrees}C have been measured in some dumps. That heat is transfered by conduction and fluid advection. Dumps have thick partly saturated zones through which gases flow under thermal gradients and water infiltrates. Oxygen is required by the oxidation reactions and is supplied by diffusion and advection. The reaction products are carried in solution in very concentrated leachates. Numerical modeling of AMD aims to (1) provide a better understanding of the physical processes involved in AMD, (2) allow the integration of available waste rock characterization data, (3) indicate new data or studies which are required to fill the gaps in our quantitative understanding of AMD processes, and (4) supply a tool for the prediction of AMD production, taking into account the impact of control methods. These objectives can only be met through sustained research efforts. This study is part of a wider research effort which as been on-going at La Mine Doyon since 1991.

Thermal aspects of radioactive waste disposal in hard rock

International Nuclear Information System (INIS)

Beale, H.; Bourke, P.J.; Hodgkinson, D.P.

1980-01-01

Buried heat emitting radioactive waste will appreciably raise the temperature of the surrounding rock over distances of several hundred metres for many centuries. This paper describes continuing research at Harwell aimed at understanding how this heating affects the design of hard rock depositories for the waste. It also considers how water-borne leakage of radionuclides from a depository to the surface might be increased by thermal convection currents through the rock mass and by thermally induced changes in its permeability and porosity. A conceptual design for a three-dimensional depository with an array of vitrified waste blocks placed in vertical boreholes is described. The maximum permissible power outputs of individual blocks and the minimum permissible separations between blocks to limit the local and bulk average rock temperatures will be determined by heat transfer through the rock and are reviewed. Interim results of a field heating experiment to study transient heat transfer through granite are discussed subsequently. Field experiments are now being started to measure the fracture permeability and porosity over large distances in virgin granite and to investigate their variation on heating and cooling the rock. Theoretical estimates of the temperatures, thermal stresses and thermal convection currents around a depository are next presented. The implications for water-borne leakage are that the induced stresses could change the fracture permeability and porosity, and thermal convection could cause substantial water movement vertically towards the surface. Finally some conclusions from the work are presented. (author)

Commercial application of bacterial heap leaching in Ganzhou uranium mine

International Nuclear Information System (INIS)

Liu Jian; Fan Baotuan; Meng Yunsheng; Xiao Jinfeng; Chen Sencai; Wu Jinjing; Liu Chengwu; Wu Yichang; Zeng Ruilong

2003-01-01

In this paper the situation of commercial application on bacterial heap leaching in Ganzhou Uranium Mine is introduced, and the construction of biomembrane oxidizing tank, regeneration and recycled utilization of barren solution are summarized. Total five heaps, 18436 t, uranium ore are leached by bacteria during the half of a year. The result is consistent with that of commercial experiment. The technology of bacterial heap leaching is more perfected

Uranium migration and retention during weathering of a granitic waste rock pile

International Nuclear Information System (INIS)

Boekhout, F.; Gérard, M.; Kanzari, A.; Michel, A.; Déjeant, A.; Galoisy, L.; Calas, G.; Descostes, M.

2015-01-01

Highlights: • We investigate the environmental impact of the granitic waste rock piles. • The majority of the waste rocks in the pile is barren- or overburden rock. • The main neo-formed U-bearing phases are (Ca) and (Cu) uranyl phosphates. • Under circum-neutral pH conditions they do not pose an environment threat. - Abstract: This study investigates the post-mining evolution of S-type granitic waste rocks around a former uranium mine, Vieilles Sagnes (Haute Vienne, NW Massif Central, France). This mine was operated between 1957 and 1965 in the La Crouzille former world-class uranium mining district and is representative of intra-granitic vein-type deposits. 50 years after mine closure and the construction and subsequent re-vegetation of the granitic waste rock pile, we evaluate the environmental evolution of the rock pile, including rock alteration, neo-formation of U-bearing phases during weathering, and U migration. Vertical trenches have been excavated through the rock pile down to an underlying paleo-soil, allowing the investigation of the vertical differentiation of the rock pile and its influence on water pathways, weathering processes and U migration and retention. Arenization dominantly drives liberation of U, by dissolution of uraninite inclusions in the most alterable granitic minerals (i.e. K-feldspar and biotite). Retention of U in the matrix at the base of the waste rock pile, and in the underlying paleo-soil most likely occurs by precipitation of (nano-) uranyl phosphates or a combination of co-precipitation and adsorption reactions of U onto Fe (oxy)hydroxides and/or clay minerals. Even though U-migration was observed, U is retained in stable secondary mineral phases, provided the current conditions will not be modified

Rock mass modification around a nuclear waste repository in welded tuff

International Nuclear Information System (INIS)

Mack, M.G.; Brandshaug, T.; Brady, B.H.

1989-08-01

This report presents the results of numerical analyses to estimate the extent of rock mass modification resulting from the presence of a High Level Waste (HLW) repository. Changes in rock mass considered are stresses and joint deformations resulting from disposal room excavation and thermal efffects induced by the heat generated by nuclear waste. rock properties and site conditions are taken from the Site Characterization Plan Conceptual Design Report for the potential repository site at Yucca Mountain, Nevada. Analyses were conducted using boundary element and distinct element methods. Room-scale models and repository-scale models were investigated for up to 500 years after waste emplacement. Results of room-scale analyses based on the thermoelastic boundary element model indicate that a zone of modified rock develops around the disposal rooms for both vertical and horizontal waste emplacement. This zone is estimated to extend a distance of roughly two room diameters from the room surface. Results from the repository-scale model, which are based on the thermoelastic boundary element model and the distinct element model, indicate a zone with modified rock mass properties starting approximately 100 m above and below the repository, with a thickness of approximately 200 m above and 150 m below the repository. Slip-prone subhorizontal features are shown to have a substantial effect on rock mass response. The estimates of rock mass modification reflect uncertainties and simplifying assumptions in the models. 32 refs., 57 figs., 1 tab

The rehabilitation of Whites overburden heap

International Nuclear Information System (INIS)

Allen, C.G.

1984-01-01

The Rum Jungle uranium mine was closed in 1971. Environmental studies have identified sources of heavy metal and acid pollution and a rehabilitation strategy for the mine site has been proposed. The objectives of the program are the significant reduction of heavy metal pollution being released by the various overburden heaps, open cuts and the tailings dam to the East Finniss River; the significant improvement of the aesthetic environment of the site; and the reduction in public health hazards at the mine. The rehabilitation strategy includes recontouring, covering, draining and revegetating the overburden heap

Modelling water and contaminant transport in the Rum Jungle Mine overburden heaps

International Nuclear Information System (INIS)

Pantelis, G.

1987-04-01

An outline is given of a computer model for water and contaminant transport in and around overburden heaps, with those at the Rum Jungle mine site as a specific example. The model assumes the heaps to lie on a sloping shallow aquifer with identical hydraulic properties. The simulation is carried out for a 40 year period. After the first 20 years a cover which is effectively impermeable to infiltrating rainwater and air is introduced on the heap. The restriction of oxygen supply to the heap terminates contaminant production which results from oxidation of pyrite. Leaching of contaminants from the heap in the following 20-year period is examined

Mine waste management

International Nuclear Information System (INIS)

Hutchinson, I.P.G.; Ellison, R.D.

1992-01-01

This book reports on mine waste management. Topics covered include: Performance review of modern mine waste management units; Mine waste management requirements; Prediction of acid generation potential; Attenuation of chemical constituents; Climatic considerations; Liner system design; Closure requirements; Heap leaching; Ground water monitoring; and Economic impact evaluation

Estimated water requirements for gold heap-leach operations

Science.gov (United States)

Bleiwas, Donald I.

2012-01-01

This report provides a perspective on the amount of water necessary for conventional gold heap-leach operations. Water is required for drilling and dust suppression during mining, for agglomeration and as leachate during ore processing, to support the workforce (requires water in potable form and for sanitation), for minesite reclamation, and to compensate for water lost to evaporation and leakage. Maintaining an adequate water balance is especially critical in areas where surface and groundwater are difficult to acquire because of unfavorable climatic conditions [arid conditions and (or) a high evaporation rate]; where there is competition with other uses, such as for agriculture, industry, and use by municipalities; and where compliance with regulatory requirements may restrict water usage. Estimating the water consumption of heap-leach operations requires an understanding of the heap-leach process itself. The task is fairly complex because, although they all share some common features, each gold heap-leach operation is unique. Also, estimating the water consumption requires a synthesis of several fields of science, including chemistry, ecology, geology, hydrology, and meteorology, as well as consideration of economic factors.

Developments of uranium and gold ores heap leaching technologies

International Nuclear Information System (INIS)

Tian Yuan; Guan Zibin; Gao Renxi

1998-01-01

The author reviews developments in heap leaching of uranium and gold ores at home and abroad, summarises condition of application. The author also presents problems having to be studied and settled urgently in heap leaching of uranium and gold ores in China

Selection of the host rock for high level radioactive waste repository in China

International Nuclear Information System (INIS)

Jin Yuanxin; Wang Wenguang; Chen Zhangru

2001-01-01

The authors has briefly introduced the experiences of the host rock selection and the host rock types in other countries for high level radioactive waste repository. The potential host rocks in China are investigated. They include granite, tuff, clay, basalt, salt, and loess. The report has expounded the distributions, scale, thickness, mineral and chemical composition, construction, petrogenesis and the ages of the rock. The possibility of these rocks as the host rock has been studied. The six pieces of distribution map of potential rocks have been made up. Through the synthetical study, it is considered that granite as the host rock of high level radioactive waste repository is possible

A model of pyritic oxidation in waste rock dumps

International Nuclear Information System (INIS)

Davis, G.B.; Ritchie, A.I.M.

1983-01-01

The oxidation of pyrite can lead to high acid levels and high concentrations of trace metals in the water that runs off and percolates through pyritic material. This is the situation at the abandoned uranium mine at Rum Jungle in the Northern Territory of Australia, where pyritic oxidation in the waste rock dumps resulting from open cut mining of the uranium orebody has led to pollution of the nearby East Branch of the Finniss River, with trace metals such as copper, manganese and zinc. Mathematical equations are formulated which describe a model of pyritic oxidation within a waste rock dump, where it is assumed that oxygen transport is the rate limiting step in the oxidation process and that oxygen is transported by gaseous diffusion through the pore space of the dump, followed by diffusion into oxidation sites within the particles that comprise the dump. The equations have been solved numerically assuming values for such parameters as porosity, sulphur density and oxygen diffusion coefficients which are applicable to the waste rock dumps at Rum Jungle. An approximate solution to the equations is also presented. Calculations of the heat source distribution and the total SO 4 production rate are presented for both single size particles and for a range of particle sizes in the dump. The usefulness of the approximate solution, and of calculations based on single size particles in the dump in assessing the effectiveness of strategies to reduce pollution from such waste rock dumps are discussed

Norman Stuart heaps 1928”1986

Science.gov (United States)

Cartwright, David E.

Dr. Norman Heaps died on June 26, 1986, in a hospital near his native town of Prescot, U.K., a suburb of Liverpool, after a long illness punctuated by bouts of painful medical treatment for lung cancer. He was the pioneer in Britain of the numerical modeling of tides and storm surges in shelf seas.He graduated at the University of Liverpool in 1949 with honors in mathematics with subsidiary physics and oceanography. Many years later the same university awarded him a doctorate on the basis of his published work. Norman's first 10 postgraduate years were spent as mathematician in the aircraft industry, but he never felt at home in the industrial world and sought a more academic career. While lecturing at the Royal College of Advanced Technology at Salford, Manchester (now the University of Salford), he struck a lasting friendship with Clifford Mortimer, FRS, then director of the Freshwater Biological Association laboratory at Lake Windermere, who first interested Heaps in the problem of computing the natural seiche oscillations of that lake. The use of electronic computers was still in its infancy, but Heaps saw that the equations of internal oscillations in such a lake could be solved numerically by methods that he had developed in the theory of wing structures. Heaps worked up a Master's thesis on this problem during his summer vacations, and he later worked with Mortimer at the University of Wisconsin on a more advanced scheme involving the coupled oscillations of Green Bay and Lake Michigan.

Worst-case analysis of heap allocations

DEFF Research Database (Denmark)

Puffitsch, Wolfgang; Huber, Benedikt; Schoeberl, Martin

2010-01-01

the worst-case heap allocations of tasks. The analysis builds upon techniques that are well established for worst-case execution time analysis. The difference is that the cost function is not the execution time of instructions in clock cycles, but the allocation in bytes. In contrast to worst-case execution...... time analysis, worst-case heap allocation analysis is not processor dependent. However, the cost function depends on the object layout of the runtime system. The analysis is evaluated with several real-time benchmarks to establish the usefulness of the analysis, and to compare the memory consumption...

Lined rock caverns for the storage of hazardous waste

International Nuclear Information System (INIS)

Semprich, S.; Speidel, S.R.; Schneider, H.J.

1987-01-01

For reasons of environmental protection the storage of hazardous waste in unlined rock caverns is possible to a very limited extent only. Therefore, the authors have recently developed technologies for the lining and sealing of rock caverns. In the process, sealing systems of synthetic materials or metals have proved suitable. Synthetic materials can be used in the form of either sheets or coatings with various materials such as epoxy resins, polyethylenes etc. being used. Metal sealings consist of thin sheets or foils which are either welded or bonded. In either case, the structural design must provide for a leakage control possibility. The article describes the design principles, the structural and operational aspects as well as the control measures with regard to the planning and execution of lined rock caverns for the storage of hazardous waste

Mixing-controlled uncertainty in long-term predictions of acid rock drainage from heterogeneous waste-rock piles

Science.gov (United States)

Pedretti, D.; Beckie, R. D.; Mayer, K. U.

2015-12-01

The chemistry of drainage from waste-rock piles at mine sites is difficult to predict because of a number of uncertainties including heterogeneous reactive mineral content, distribution of minerals, weathering rates and physical flow properties. In this presentation, we examine the effects of mixing on drainage chemistry over timescales of 100s of years. We use a 1-D streamtube conceptualization of flow in waste rocks and multicomponent reactive transport modeling. We simplify the reactive system to consist of acid-producing sulfide minerals and acid-neutralizing carbonate minerals and secondary sulfate and iron oxide minerals. We create multiple realizations of waste-rock piles with distinct distributions of reactive minerals along each flow path and examine the uncertainty of drainage geochemistry through time. The limited mixing of streamtubes that is characteristic of the vertical unsaturated flow in many waste-rock piles, allows individual flowpaths to sustain acid or neutral conditions to the base of the pile, where the streamtubes mix. Consequently, mixing and the acidity/alkalinity balance of the streamtube waters, and not the overall acid- and base-producing mineral contents, control the instantaneous discharge chemistry. Our results show that the limited mixing implied by preferential flow and the heterogeneous distribution of mineral contents lead to large uncertainty in drainage chemistry over short and medium time scales. However, over longer timescales when one of either the acid-producing or neutralizing primary phases is depleted, the drainage chemistry becomes less controlled by mixing and in turn less uncertain. A correct understanding of the temporal variability of uncertainty is key to make informed long-term decisions in mining settings regarding the management of waste material.

Sawmill "Waste"

Science.gov (United States)

Fred C. Simmons; Adna R. Bond

1955-01-01

Sawmills have the reputation of being very wasteful in converting logs and bolts into lumber and timbers. Almost everyone has seen the great heaps of sawdust and slabs that collect at sawmills. Frequently the question is asked, "Why doesn't somebody do something about this terrible waste of wood?"

Present and future: heap leaching of uranium ore in China

International Nuclear Information System (INIS)

Li Jianhua

2010-01-01

Based on small and disperse uranium deposits, and low grade ores, heap leaching has been developed as the dominating technique in the uranium production of China. It is indicated that heap leaching technique has such advantages as less capital, low cost, low power consumption and water consumption. At the meanwhile, heap leaching technique presents shortcomings of poor adaptability and low recovery rate. In order to meet the oncoming enormous demand of nuclear power, great effort shall be put on research of new technology, new equipment, new material. (authors)

Rock support for nuclear waste repositories

International Nuclear Information System (INIS)

Abramson, L.W.; Schmidt, B.

1984-01-01

The design of rock support for underground nuclear waste repositories requires consideration of special construction and operation requirements, and of the adverse environmental conditions in which some of the support is placed. While repository layouts resemble mines, design, construction and operation are subject to quality assurance and public scrutiny similar to what is experienced for nuclear power plants. Exploration, design, construction and operation go through phases of review and licensing by government agencies as repositories evolve. This paper discusses (1) the various stages of repository development; (2) the environment that supports must be designed for; (3) the environmental effects on support materials; and (4) alternative types of repository rock support

Appraisal of hard rock for potential underground repositories of radioactive wastes

International Nuclear Information System (INIS)

Cook, N.G.W.

1977-10-01

The mechanical safety and stability of such an underground repository depends largely on the virgin state of stress in the rock, groundwater pressures, the strengths of the rocks, heating by the decay of the radioactive wastes, and the layout of the excavations and the disposition of waste cannisters within them. A large body of pertinent data exists in the literature, and each of these factors has been analyzed in the light of this information. The results indicate that there are no fundamental geological nor mechanical reasons why repositories capable of storing radioactive wastes should not be excavated at suitable sites in hard rock. However, specific tests to determine the mechanical and thermal properties of the rocks at a site would be needed to provide the data for the engineering design of a repository. Also, little experience exists of the effects on underground excavations of thermal loads, so that this aspect requires theoretical study and experimental validation. The depths of these potential repositories would lie in the range from 0.5 to 2.0 km below surface, depending upon the strength of the rock. Virgin states of stress have been measured at such depths which would retard the ingress of groundwater and obviate the incidence of faulting. A typical repository comprising three horizons each with a total area of 5 km 2 would have the capacity to store wastes with thermal output of 240 MW

A Rock Mechanics and Coupled Hydro mechanical Analysis of Geological Repository of High Level Nuclear Waste in Fractured Rocks

International Nuclear Information System (INIS)

Min, Kibok

2011-01-01

This paper introduces a few case studies on fractured hard rock based on geological data from Sweden, Korea is one of a few countries where crystalline rock is the most promising rock formation as a candidate site of geological repository of high level nuclear waste. Despite the progress made in the area of rock mechanics and coupled hydro mechanics, extensive site specific study on multiple candidate sites is essential in order to choose the optimal site. For many countries concerned about the safe isolation of nuclear wastes from the biosphere, disposal in a deep geological formation is considered an attractive option. In geological repository, thermal loading continuously disturbs the repository system in addition to disturbances a recent development in rock mechanics and coupled hydro mechanical study using DFN(Discrete Fracture Network) - DEM(Discrete Element Method) approach mainly applied in hard, crystalline rock containing numerous fracture which are main sources of deformation and groundwater flow

Rock-welding materials for deep borehole nuclear waste disposal.

Energy Technology Data Exchange (ETDEWEB)

Yang, Pin [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Wang, Yifeng [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Rodriguez, Mark A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Brady, Patrick Vane [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Swift, Peter N. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2015-11-01

The concept of deep borehole nuclear waste disposal has recently been proposed. Effective sealing of a borehole after waste emplacement is generally required. In a high temperature disposal mode, the sealing function will be fulfilled by melting the ambient granitic rock with waste decay heat or an external heating source, creating a melt that will encapsulate waste containers or plug a portion of the borehole above a stack of the containers. However, there are certain drawbacks associated with natural materials, such as high melting temperatures, slow crystallization kinetics, the resulting sealing materials generally being porous with low mechanical strength, insufficient adhesion to waste container surface, and lack of flexibility for engineering controls. Here we show that natural granitic materials can be purposefully engineered through chemical modifications to enhance the sealing capability of the materials for deep borehole disposal. This work systematically explores the effect of chemical modification and crystallinity (amorphous vs. crystalline) on the melting and crystallization processes of a granitic rock system. A number of engineered granitic materials have been obtained that have decreased melting points, enhanced viscous densification, and accelerated recrystallization rates without compromising the mechanical integrity of the materials.

Rock mechanics in the disposal of radioactive wastes by hydraulic fracturing

Energy Technology Data Exchange (ETDEWEB)

McClain, W C

1968-01-01

The ultimate capacity of a hydraulic-fracturing waste disposal facility is governed primarily by the integrity of the rocks overlying the injected wastes. The objective of this study is to analyze theoretically the stresses and strains generated by the injected wastes in an effort to understand the behavior of the system sufficiently well that the failure mechanism can be predicted and the capacity of the injection well estimated. The surface uplifts at Oak Ridge National Laboratory's fracturing site were compared with theoretical curves obtained by assuming the uplifts to be inversely analogous to the subsidence which occurs over mining excavations. This analysis, based on assumptions of homogeneity, isotropy, and linear elasticity, provided considerable insight into the mechanics of the process. The most probable mechanism of failure of the rock appears to be by the formation of a vertical instead of a horizontal fracture. Fracture orientation is controlled primarily by the orientation of the principal stress field in the rock. Each successive waste injection slightly modifies this stress field toward a condition more favorable to the formation of a vertical fracture. (16 refs.)

The formation of technic soil in a revegetated uranium ore waste rock pile (Limousin, France)

Science.gov (United States)

Boekhout, Flora; Gérard, Martine; Kanzari, Aisha; Calas, Georges; Descostes, Michael

2014-05-01

Mining took place in France between 1945 and 2001 during which time ~210 different sites were exploited and/or explored. A total of 76 Kt of uranium was produced, 52 Mt of ore was extracted, but also 200 Mt of waste rocks was produced, the majority of which, with uranium levels corresponding to the natural environment. So far, the processes of arenisation and technic soil formation in waste rock piles are not well understood but have important implications for understanding the environmental impact and long-term speciation of uranium. Understanding weathering processes in waste rock piles is essential to determine their environmental impact. The main objectives of this work are to assess 1) the micromorphological features and neo-formed U-bearing phases related to weathering and 2) the processes behind arenisation of the rock pile. The site that was chosen is the Vieilles Sagnes waste rock pile in Fanay (Massif Central France) that represents more or less hydrothermally altered granitic rocks that have been exposed to weathering since the construction of the waste rock pile approximately 50 years ago. Two trenches were excavated to investigate the vertical differentiation of the rock pile. This site serves as a key location for studying weathering processes of waste rock piles, as it has not been reworked after initial construction and has therefore preserved information on the original mineralogy of the waste rock pile enabling us to access post emplacement weathering processes. The site is currently overgrown by moss, meter high ferns and small trees. At present day the rock pile material can be described as hydrothermally altered rocks and rock fragments within a fine-grained silty clay matrix exposed to surface conditions and weathering. A sandy "paleo" technic soil underlies the waste rock pile and functions as a natural liner by adsorption of uranium on clay minerals. Post-mining weathering of rock-pile material is superimposed on pre-mining hydrothermal and

Transient diffusion from a waste solid into fractured porous rock

International Nuclear Information System (INIS)

Ahn, J.; Chambre, P.L.; Pigford, T.H.

1988-01-01

Previous analytical studies of the advective transport of dissolved contaminants through fractured rock have emphasized the effect of molecular diffusion in the rock matrix in affecting the space-time-dependent concentration of the contaminant as it moves along the fracture. Matrix diffusion only in the direction normal to the fracture surface was assumed. Contaminant sources were constant-concentration surfaces of width equal to the fracture aperture and of finite or infinite extent in the transverse direction. Such studies illustrate the far-field transport features of fractured media. To predict the time-dependent mass transfer from a long waste cylinder surrounded by porous rock and intersected by a fracture, the present study includes diffusion from the waste surface directly into porous rock, as well as the more realistic geometry. Here the authors present numerical results from Chambre's analytical solution for the time-dependent mass transfer from the cylinder for the low-flow conditions wherein near-field mass transfer is expected to be controlled by molecular diffusion

Vertical Object Layout and Compression for Fixed Heaps

Science.gov (United States)

Titzer, Ben L.; Palsberg, Jens

Research into embedded sensor networks has placed increased focus on the problem of developing reliable and flexible software for microcontroller-class devices. Languages such as nesC [10] and Virgil [20] have brought higher-level programming idioms to this lowest layer of software, thereby adding expressiveness. Both languages are marked by the absence of dynamic memory allocation, which removes the need for a runtime system to manage memory. While nesC offers code modules with statically allocated fields, arrays and structs, Virgil allows the application to allocate and initialize arbitrary objects during compilation, producing a fixed object heap for runtime. This paper explores techniques for compressing fixed object heaps with the goal of reducing the RAM footprint of a program. We explore table-based compression and introduce a novel form of object layout called vertical object layout. We provide experimental results that measure the impact on RAM size, code size, and execution time for a set of Virgil programs. Our results show that compressed vertical layout has better execution time and code size than table-based compression while achieving more than 20% heap reduction on 6 of 12 benchmark programs and 2-17% heap reduction on the remaining 6. We also present a formalization of vertical object layout and prove tight relationships between three styles of object layout.

Temperature loading and rocks mechanics at final storage of radioactive waste

International Nuclear Information System (INIS)

Leijon, B.; Stephansson, O.

1979-01-01

This report describes the rock mechanical effects - in the far field - from the thermal loading at a final storage of radioactive waste in crystalline rocks. The stress distribution of a two-storey storage is described in more details. The temperature rise in a final storage of radiactive waste will create thermal stresses which may cause a failure of the rock mass, and thereby an increase of its permeability. However, the state of stress in the Earth's crust is able to neutralize the thermal stresses. By this analysis we have been able to demonstrate that the thermal stresses due to heat conduction from the final storage are compensated by the state of stress in the upper part of the crust. The absolute stress, which is the superposition of thermal stress and virgin rock stress, is in all cases found to be below the limit of failure due to frictional resistance between surfaces of constituent blocks in the rock mass. Failure by sliding friction is the most conservative failure criterion for a rock mass. (author)

Engineering assessment of inactive uranium mill tailings: Slick Rock sites, Slick Rock, Colorado

International Nuclear Information System (INIS)

1981-09-01

Ford, Bacon and Davis Utah, Inc., has reevaluated the Slick Rock sites in order to revise the October 1977 engineering radioactive uranium mill tailings at Slick Rock, 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 387,000 tons of tailings at the Slick Rock sites constitutes the most significant environmental impact, although windblown tailings and external gamma radiation also are factors. The five alternative actions presented in this engineering assessment include millsite decontamination with the addition of 3 m of stabilization cover material, consolidation of the piles, and removal of the tailings to remote disposal sites and decontamination of the tailings sites. Cost estimates for the five options range from about $6,800,000 for stabilization in-place, to about $11,000,000 for disposal at a distance of about 6.5 mi. Three principal alternatives for the reprocessing of the Slick Rock tailings were examined: heap leaching; treatment at an existing mill; and reprocessing at a new conventional mill constructed for tailings reprocessing. The cost of the uranium recovered would be over $800/lb of U 3 O 8 whether by conventional or heap leach plant processes. The spot market price for uranium was $25/lb early in 1981. Therefore, reprocessing the tailings for uranium recovery is not economically attractive at present, nor for the foreseeable future

Engineering assessment of inactive uranium mill tailings: Slick Rock sites, Slick Rock, Colorado

Energy Technology Data Exchange (ETDEWEB)

None

1981-09-01

Ford, Bacon and Davis Utah, Inc., has reevaluated the Slick Rock sites in order to revise the October 1977 engineering radioactive uranium mill tailings at Slick Rock, 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 387,000 tons of tailings at the Slick Rock sites constitutes the most significant environmental impact, although windblown tailings and external gamma radiation also are factors. The five alternative actions presented in this engineering assessment include millsite decontamination with the addition of 3 m of stabilization cover material, consolidation of the piles, and removal of the tailings to remote disposal sites and decontamination of the tailings sites. Cost estimates for the five options range from about $6,800,000 for stabilization in-place, to about $11,000,000 for disposal at a distance of about 6.5 mi. Three principal alternatives for the reprocessing of the Slick Rock tailings were examined: heap leaching; treatment at an existing mill; and reprocessing at a new conventional mill constructed for tailings reprocessing. The cost of the uranium recovered would be over $800/lb of U/sub 3/O/sub 8/ whether by conventional or heap leach plant processes. The spot market price for uranium was $25/lb early in 1981. Therefore, reprocessing the tailings for uranium recovery is not economically attractive at present, nor for the foreseeable future.

Appraisal of hard rock for potential underground repositories of radioactive wastes. LBL-7004

International Nuclear Information System (INIS)

Cook, N.G.W.

1978-01-01

Underground burial of radioactive wastes in hard rock may be an effective and safe means of isolating them from the environment and from man. The mechanical safety and stability of such an underground repository depends largely on the virgin state of stress in the rock, groundwater pressures, the strengths of the rocks, heating by the decay of the radioactive wastes, and the layout of the excavations and the disposition of waste cannisters within them. A large body of pertinent data exists in the literature, and each of these factors has been analyzed in the light of this information. The results indicate that there are no fundamental geological nor mechanical reasons why repositories capable of storing radioactive wastes should not be excavated at suitable sites in hard rock. However, specific tests to determine the mechanical and thermal properties of the rocks at a site would be needed to provide the data for the engineering design of a repository. Also, little experience exists of the effects on underground excavations of thermal loads, so that this aspect requires theoretical study and experimental validation. The depths of these potential repositories would lie in the range from 0.5 km to 2.0 km below surface, depending upon the strength of the rock. Virgin states of stress have been measured at such depths which would retard the ingress of groundwater and obviate the incidence of faulting. A typical repository comprising three horizons each with a total area of 5 km 2 would have the capacity to store wastes with thermal output of 240 MW

Main ways and suitable technologies of improving economic benefits for uranium ore heap leaching in China (the end)

International Nuclear Information System (INIS)

Guan Zibin

2001-01-01

Combining with practice of China's uranium ore heap leaching, the author proposes main ways and suitable technologies in the fields of emphasizing feasibility research, adopting strengthened technologies, improving equipment level, optimizing control technological factors and developing application range and so on, which include adopting acid-currying and ferric sulphate-trickle leaching process, bacteria heap leaching, countercurrent heap leaching, selecting advanced material of heap bottom, developing large mechanized heap construction equipment and methods, popularizing drip irrigation distributing solution, optimizing heap leaching process parameters, as well as developing recovery equipment suited to heap leaching, etc, in order to increase leaching rate, reduce heap leaching period and achieve more economic benefits

Rock stresses associated with burial of nuclear waste

International Nuclear Information System (INIS)

Voight, B.

1977-01-01

Rock stress changes related to long-term deep storage of nuclear waste involve thermoelastic and pore fluid pressure changes associated with excavation and heating. Computer models are being examined to assess the question of thermally-induced fracturing in storage rock surrounding radioactive waste containers. Stresses are evaluated in three dimensions, employing elastic-plastic finite element codes. Potential failure conditions are expressed in terms of ''effective stresses,'' and force and thermal fields are incremented to produce an appropriate load path. In general, heating in vicinity of waste containers produces a zone of high compression bonded by a zone of circumferential and axial tension. (At this conference an analogous case of thermal stresses was documented and illustrated for larger-scale temperature domains associated with geothermal areas in Iceland.) Fractures are possible in radial directions as well as perpendicular to the axis of the cylindrical heat source. In addition, the mechanical effect of a vapor pulse will be explored by a two-phase numerical fluid transport model used in conjunction with mechanical finite element models. This portion of the work, being conducted jointly with C. R. Faust and J. W. Mercer of the US Geological Survey, should provide a preliminary appreciation of the possible effect of phase changes on fracturing of burial sites. Preliminary work suggests the possibility of establishing design criteria (e.g., design burial depth, depth of canister below storage vault) in order to minimize problems of potential rock fracture

Thermal characteristics of rocks for high-level waste repository

International Nuclear Information System (INIS)

Shimooka, Kenji; Ishizaki, Kanjiro; Okamoto, Masamichi; Kumata, Masahiro; Araki, Kunio; Amano, Hiroshi

1980-12-01

Heat released by the radioactive decay of high-level waste in an underground repository causes a long term thermal disturbance in the surrounding rock mass. Several rocks constituting geological formations in Japan were gathered and specific heat, thermal conductivity, thermal expansion coefficient and compressive strength were measured. Thermal analysis and chemical analysis were also carried out. It was found that volcanic rocks, i.e. Andesite and Basalt had the most favorable thermal characteristics up to around 1000 0 C and plutonic rock, i.e. Granite had also favorable characteristics under 573 0 C, transition temperature of quartz. Other igneous rocks, i.e. Rhyolite and Propylite had a problem of decomposition at around 500 0 C. Sedimentary rocks, i.e. Zeolite, Tuff, Sandstone and Diatomite were less favorable because of their decomposition, low thermal conductivity and large thermal expansion coefficient. (author)

Carbonate heap leach of uranium-contaminated soils

International Nuclear Information System (INIS)

Turney, W.R.; Mason, C.F.V.; Longmire, P.

1994-01-01

A new approach to removal of uranium from soils based on existing heap leach mining technologies proved highly effective for remediation of soils from the Fernald Environmental Management Project (FEMP) near Cincinnati, Ohio. In laboratory tests, remediation of uranium-contaminated soils by heap leaching with carbonate salt solutions was demonstrated in column experiments. An understanding of the chemical processes that occur during carbonate leach of uranium from soils may lead to enhancement of uranium removal. Carbonate leaching requires the use of an integrated and closed circuit process, wherein the leach solutions are recycled and the reagents are reused, resulting in a minimum secondary waste stream. Carbonate salt leach solution has two important roles. Primarily, the formation of highly soluble anionic carbonate uranyl species, including uranyl dicarbonate (UO 2 CO 32 = ) and uranyl tricarbonate (UO 2 CO 33 4- ), allows for high concentration of uranium in a leachate solution. Secondly, carbonate salts are nearly selective for dissolution of uranium from uranium contaminated soils. Other advantages of the carbonate leaching process include (1) the high solubility, (2) the selectivity, (3) the purity of the solution produced, (4) the relative ease with which a uranium product can be precipitated directly from the leachate solution, and (5) the relatively non-corrosive and safe handling characteristics of carbonate solutions. Experiments conducted in the laboratory have demonstrated the effectiveness of carbonate leach. Efficiencies of uranium removal from the soils have been as high as 92 percent. Higher molar strength carbonate solutions (∼0.5M) proved more effective than lower molar strength solutions (∼ 0.1M). Uranium removal is also a function of lixiviant loading rate. Furthermore, agglomeration of the soils with cement resulted in less effective uranium removal

Research on base rock mechanic characteristics of caverns for radioactive waste disposal

International Nuclear Information System (INIS)

Isei, Takehiro; Katsuyama, Kunihisa; Seto, Masahiro; Ogata, Yuji; Utagawa, Manabu

1997-01-01

It has been considered that underground space is mechanically stable as compared with on the ground, and superior for storing radioactive waste for long period. However, in order to utilize underground space for the place of radioactive waste disposal, its long term stability such as the aseismatic ability of base rocks must be ensured, and for this purpose, it is necessary to grasp the mechanical characteristics of the base rocks around caverns, and to advance the technology for measuring and evaluating minute deformation and earth pressure change. In this research, the study on the fracture mechanics characteristics of base rocks and the development of the technology for measuring long terms stress change of base rocks were carried out. In this research, what degree the memory of past stress is maintained by rocks was presumed by measuring AE and strain when stress was applied to rock test pieces. The rocks tested were tuff, sandstone and granite. The experimental method and the experimental results of the prestress by AE method and DRA are reported. (K.I.)

Improvements on heap leaching process for a refractory uranium ore and yellow cake precipitation process

International Nuclear Information System (INIS)

Feng Jianke

2013-01-01

Some problems such as formed harden matrix, ore heap compaction, poor permeability, and agglomeration of absorption resin occur during extracting uranium from a refractory uranium ore by heap leaching process. After some measures were taken, i.e. spraying a new ore heap by low concentration acid, two or more ore heaps in series leaching, turning ores in ore heap, the permeability was improved, acid consumption was reduced. Through precipitate circulation and aging, the yellow cake slurry in amorphous or microlite form was transformed to crystal precipitate, thus uranium content in yellow cake was improved, and water content in yellow cake was lowered with good economic benefits. (author)

Symmetric Rock Fall on Waste Package

International Nuclear Information System (INIS)

Sreten Mastilovic

2001-01-01

The objective of this calculation is to determine the structural response of the Naval SNF (spent nuclear fuel) Waste Package (WP) and the emplacement pallet (EP) subjected to the rock fall DBE (design basis event) dynamic loads. The scope of this calculation is limited to reporting the calculation results in terms of stress intensities and residual stresses in the WP, and stress intensities and maximum permanent downward displacements of the EP-lifting surface. The information provided by the sketches (Attachment I) is that of the potential design of the type of WP and EP considered in this calculation, and all obtained results are valid for those designs only. This calculation is associated with the waste package design and is performed by the Waste Package Design Section in accordance with Reference 24. AP-3.124, ''Calculations'', is used to perform the calculation and develop the document

Successful approaches. Sports stars and HEAPS.

Science.gov (United States)

1996-01-01

In western Samoa, football stars are being used in the fight against acquired immunodeficiency syndrome (AIDS). Originally recruited by Palanitina Toelupe, chief health educator of the Health Education and Promotion Section (HEAPS), to assist with an anti-smoking campaign, the players became sensitized to issues regarding AIDS and agreed to visit high schools where they could urge young people to "Learn the Facts (about AIDS) and Pass the Word." With assistance from the SPC, HEAPS produced and broadcast radio and TV spots featuring the athletes; a poster was printed and distributed. Sports stars travel regionally and internationally; those with knowledge of AIDS and unsafe sex behavior can reinforce responsible sexual behavior among their teammates. Sports people should be targeted for AIDS and sexually transmitted disease (STD) education and prevention.

Summary review of rock mechanics workshop on radioactive waste disposal

International Nuclear Information System (INIS)

Carter, N.L.; Goodman, R.E.; Merrill, R.H.

1977-01-01

Presentations, critiques and recommendations for the disposal of commercial radioactive waste based upon an analysis of the information presented at the Rock Mechanics Review/Workshop, Denver, Colorado, December 16-17, 1976 are summarized. The workshop, comprised of both formal and informal sessions, with about 50 participants, was hosted by RE/SPEC Inc. and Dr. Paul F. Gnirk, President and was sponsored by the Office of Waste Isolation (OWI), led by Dr. William C. McClain. The panel of reviewers, responsible for this report, consisted of Neville L. Carter, Richard E. Goodman, and Robert H. Merrill. These panel members were selected not only on the basis of their experience in various aspects of Rock Mechanics and Mining Engineering but also because they have had no previous active participation in problems concerning disposal of radioactive waste. By way of a general comment, the review panel was very favorably impressed with the Rock Mechanics research efforts, supported by OWI, on this problem and with the level of technical competence of those carrying out the research. Despite the rather preliminary nature of the results presented and the youth of the program itself, it is clear that the essential ingredients for a successful program are at hand, especially as regards disposal in natural salt formations. These include laboratory studies of appropriate rock deformation, numerical analyses of thermal and mechanical stresses around openings, and in situ field tests. We shall comment on each of these three major areas in turn. We shall then offer recommendations for their improvement, and, finally, we shall make more general recommendations for future considerations of the OWI radioactive waste disposal program

Technical application of agglomerated acidic heap leaching of clay-bearing uranium ore in China

International Nuclear Information System (INIS)

Zeng Yijun; Li Jianhua; Li Tieqiu; Zhong Pingru

2002-01-01

The permeability of ore mass has a great influence on the leaching period of heap leaching and the leaching efficiency, hence the uranium ores with high content of clay is difficult to acidic heap leaching. The Research Institute of Uranium Mining has engaged several years studies on the cementing agents of acidic agglomeration, agglomeration conditions, as well as the curing measures of agglomerated balls. On the basis of these studies, several types of clay-bearing ores have been tested with good results. The technique of agglomerated acidic heap leaching has been successfully applied in a uranium mine. Since agglomeration has effectively increased the permeability of ore heap, its leaching period is decreased from 200 days to 60 days, the leaching efficiency is increased to 96% from less than 40% comparing with direct heap leaching program

The geochemistry of high-level waste disposal in granitic rocks

International Nuclear Information System (INIS)

Chapman, N.A.; Sargent, F.P.

1984-01-01

Under the auspices of the cooperative agreement between Euratom and Atomic Energy of Canada Ltd about radioactive waste management and disposal, a joint workshop was held on the topic of the geochemistry of high-level waste disposal in granitic rocks. The report covers (1) waste form leaching, (2) thermodynamics, (3) geochemical models, (4) the role of colloids, (5) sorption phenomena, (6) the linking of flow and geochemical models, (7) microbial activity

Modelling temperature-dependent heat production over decades in High Arctic coal waste rock piles

DEFF Research Database (Denmark)

Hollesen, Jørgen; Elberling, Bo; Jansson, P.E.

2011-01-01

Subsurface heat production from oxidation of pyrite is an important process that may increase subsurface temperatures within coal waste rock piles and increase the release of acid mine drainage, AMD. Waste rock piles in the Arctic are especially vulnerable to changes in subsurface temperatures...... such as heat production from coal oxidation may be equally important....... as the release of AMD normally is limited by permafrost. Here we show that temperatures within a 20 year old heat-producing waste rock pile in Svalbard (78°N) can be modelled by the one-dimensional heat and water flow model (CoupModel) with a new temperature-dependent heat-production module that includes both...

Molybdenum and zinc stable isotope variation in mining waste rock drainage and waste rock at the Antamina mine, Peru

Energy Technology Data Exchange (ETDEWEB)

Skierszkan, E.K., E-mail: eskiersz@eos.ubc.ca [Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, 2020-2207 Main Mall, Vancouver V6T 1Z4 (Canada); Mayer, K.U. [Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, 2020-2207 Main Mall, Vancouver V6T 1Z4 (Canada); Weis, D. [Pacific Centre for Isotopic and Geochemical Research (PCIGR), Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, 2020-2207 Main Mall, Vancouver V6T 1Z4 (Canada); Beckie, R.D. [Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, 2020-2207 Main Mall, Vancouver V6T 1Z4 (Canada)

2016-04-15

The stable isotope composition of molybdenum (Mo) and zinc (Zn) in mine wastes at the Antamina Copper–Zn–Mo mine, Peru, was characterized to investigate whether isotopic variation of these elements indicated metal attenuation processes in mine drainage. Waste rock and ore minerals were analyzed to identify the isotopic composition of Mo and Zn sources, namely molybdenites (MoS{sub 2}) and sphalerites (ZnS). Molybdenum and Zn stable isotope ratios are reported relative to the NIST-SRM-3134 and PCIGR-1 Zn standards, respectively. δ{sup 98}Mo among molybdenites ranged from − 0.6 to + 0.6‰ (n = 9) while sphalerites showed no δ{sup 66}Zn variations (0.11 ± 0.01‰, 2 SD, n = 5). Mine drainage samples from field waste rock weathering experiments were also analyzed to examine the extent of isotopic variability in the dissolved phase. Variations spanned 2.2‰ in δ{sup 98}Mo (− 0.1 to + 2.1‰) and 0.7‰ in δ{sup 66}Zn (− 0.4 to + 0.3‰) in mine drainage over a wide pH range (pH 2.2–8.6). Lighter δ{sup 66}Zn signatures were observed in alkaline pH conditions, which was consistent with Zn adsorption and/or hydrozincite (Zn{sub 5}(OH){sub 6}(CO{sub 3}){sub 2}) formation. However, in acidic mine drainage Zn isotopic compositions reflected the value of sphalerites. In addition, molybdenum isotope compositions in mine drainage were shifted towards heavier values (0.89 ± 1.25‰, 2 SD, n = 16), with some overlap, in comparison to molybdenites and waste rock (0.13 ± 0.82‰, 2 SD, n = 9). The cause of heavy Mo isotopic signatures in mine drainage was more difficult to resolve due to isotopic heterogeneity among ore minerals and a variety of possible overlapping processes including dissolution, adsorption and secondary mineral precipitation. This study shows that variation in metal isotope ratios are promising indicators of metal attenuation. Future characterization of isotopic fractionation associated to key environmental reactions will improve the power

Molybdenum and zinc stable isotope variation in mining waste rock drainage and waste rock at the Antamina mine, Peru

International Nuclear Information System (INIS)

Skierszkan, E.K.; Mayer, K.U.; Weis, D.; Beckie, R.D.

2016-01-01

The stable isotope composition of molybdenum (Mo) and zinc (Zn) in mine wastes at the Antamina Copper–Zn–Mo mine, Peru, was characterized to investigate whether isotopic variation of these elements indicated metal attenuation processes in mine drainage. Waste rock and ore minerals were analyzed to identify the isotopic composition of Mo and Zn sources, namely molybdenites (MoS_2) and sphalerites (ZnS). Molybdenum and Zn stable isotope ratios are reported relative to the NIST-SRM-3134 and PCIGR-1 Zn standards, respectively. δ"9"8Mo among molybdenites ranged from − 0.6 to + 0.6‰ (n = 9) while sphalerites showed no δ"6"6Zn variations (0.11 ± 0.01‰, 2 SD, n = 5). Mine drainage samples from field waste rock weathering experiments were also analyzed to examine the extent of isotopic variability in the dissolved phase. Variations spanned 2.2‰ in δ"9"8Mo (− 0.1 to + 2.1‰) and 0.7‰ in δ"6"6Zn (− 0.4 to + 0.3‰) in mine drainage over a wide pH range (pH 2.2–8.6). Lighter δ"6"6Zn signatures were observed in alkaline pH conditions, which was consistent with Zn adsorption and/or hydrozincite (Zn_5(OH)_6(CO_3)_2) formation. However, in acidic mine drainage Zn isotopic compositions reflected the value of sphalerites. In addition, molybdenum isotope compositions in mine drainage were shifted towards heavier values (0.89 ± 1.25‰, 2 SD, n = 16), with some overlap, in comparison to molybdenites and waste rock (0.13 ± 0.82‰, 2 SD, n = 9). The cause of heavy Mo isotopic signatures in mine drainage was more difficult to resolve due to isotopic heterogeneity among ore minerals and a variety of possible overlapping processes including dissolution, adsorption and secondary mineral precipitation. This study shows that variation in metal isotope ratios are promising indicators of metal attenuation. Future characterization of isotopic fractionation associated to key environmental reactions will improve the power of Mo and Zn isotope ratios to track the fate

SUITABILITY ANALYSIS OF WASTE ROCK APPLICATION IN HYDRIC RECLAMATION IN THE NATURAL WATER-BEARING SUBSIDENCE TROUGHS IN KARVINSKO, CZECH REPUBLIC

Directory of Open Access Journals (Sweden)

Eva Pertile

2008-12-01

Full Text Available The paper deals with a suitability analysis of waste rock application in hydric reclamation on the basis of studying its impact on water quality in the natural water-bearing subsidence troughs. The evaluation was carried out in sixteen localities where waste rock had been used in the past for the purposes of bank system improvement. Within the evaluation of waste rock impact on the hydrochemical character of water in the subsidence troughs the values of geochemical background were identified. In order to compare the impact of waste rock on the quality of water, changes in the hydrochemical parameters were monitored in the localities without waste rock banking, with partial (maximum ½ circumference and complete waste rock banking.

Technical support for GEIS: radioactive waste isolation in geologic formations. Volume 7. Baseline rock properties-basalt

International Nuclear Information System (INIS)

1978-04-01

This volume, Y/OWI/TM-36/7 Baseline Rock Properties--Basalt, is one of a 23-volume series, ''Technical Support for GEIS: Radioactive Waste Isolation in Geologic Formations, Y/OWI/TM-36'' which supplements a ''Contribution to Draft Generic Environmental Impact Statement on Commercial Waste Management: Radioactive Waste Isolation in Geologic Formations, Y/OWI/TM-44.'' The series provides a more complete technical basis for the preconceptual designs, resource requirements, and environmental source terms associated with isolating commercial LWR wastes in underground repositories in salt, granite, shale and basalt. Wastes are considered from three fuel cycles: uranium and plutonium recycling, no recycling of spent fuel and uranium-only recycling. This report contains an evaluation of the results of a literature survey to define the rock mass properties of a generic basalt, which could be considered as a geological medium for storing radioactive waste. The general formation and structure of basaltic rocks is described. This is followed by specific descriptions and rock property data for the Dresser Basalt, the Amchitka Island Basalt, the Nevada Test Site Basalt and the Columbia River Group Basalt. Engineering judgment has been used to derive the rock mass properties of a typical basalt from the relevant intact rock property data and the geological information pertaining to structural defects, such as joints and faults

High-level radioactive waste isolation by incorporation in silicate rock

International Nuclear Information System (INIS)

Schwartz, L.L.; Cohen, J.J.; Lewis, A.E.; Braun, R.L.

1978-01-01

A number of technical possibilities for isolating high-level radioactive materials have been theoretically investigated at various times and places. Isolating such wastes deep underground to ensure long term removal from the biosphere is one such possibility. The present concept involves as a first step creating the necessary void space at considerable depth, say 2 to 5 km, in a very-low-permeability silicate medium such as shale. Waste in dry, calcined or vitrified form is then lowered into the void space, and the access hole or shaft sealed. Energy released by the radioactive decay raises the temperature to a point where the surrounding rock begins to melt. The waste is then dissolved in it. The extent of this melt region grows until the heat generated is balanced by conduction away from the molten zone. Resolidification then begins, and ends when the radioactive decay has progressed to the point that the temperature falls below the melting point of the rock-waste solution. Calculations are presented showing the growth and resolidification process. A nuclear explosion is one way of creating the void space. (author)

Surrounding rock stress analysis of underground high level waste repository

International Nuclear Information System (INIS)

Liu Wengang; Wang Ju; Wang Guangdi

2006-01-01

During decay of nuclear waste, enormous energy was released, which results in temperature change of surrounding rock of depository. Thermal stress was produced because thermal expansion of rock was controlled. Internal structure of surrounding rock was damaged and strength of rock was weakened. So, variation of stress was a dynamic process with the variation of temperature. BeiShan region of Gansu province was determined to be the depository field in the future, it is essential to make research on granite in this region. In the process of experiment, basic physical parameters of granite were analyzed preliminary with MTS. Long range temperature and stress filed was simulated considering the damage effect of surrounding rock, and rules of temperature and stress was achieved. (authors)

To accelerate technology of in situ leaching and heap leaching for mining mineral resources of China

International Nuclear Information System (INIS)

Luo Mei

1999-01-01

Recently, in situ leaching and heap leaching are the most advanced technology for mining low-grade mineral resources in the world. The author briefly expounds the basic concept and advantages of in situ leaching and heap leaching and deals with the main research content of the hydrometallurgical technology of in situ leaching and heap leaching, its development and present application at home and abroad. Having expounded the gap existing between China's technology of in situ leaching and heap leaching and the foreign technology, the author forecasts the prospects of accelerating the mining of China's mineral resources by using the technology of in situ leaching and heap leaching

Summary of the engineering assessment of inactive uranium mill tailings: Slick Rock sites, Slick Rock, Colorado

International Nuclear Information System (INIS)

1981-09-01

Ford, Bacon and Davis Utah, Inc., has reevaluated the Slick Rock sites in order to revise the October 1977 engineering assessment of the problems resulting from the existence of radioactive uranium mill tailings at Slick Rock, Colorado. This engineering assessment has included the preparation of topographic maps, the performance of core drillings 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 387,000 tons of tailings at the Slick Rock sites constitutes the most significant environmental impact, although windblown tailings and external gamma radiation also are factors. The five alternative actions presented in this engineering assessment include millsite decontamination with the addition of 3 m of stabilization cover material, consolidation of the piles, and removal of the tailings to remote disposal sites and decontamination of the tailings sites. Cost estimates for the five options range from about $6,800,000 for stabilization in-place, to about $11,000,000 for disposal at a distance of about 6.5 mi. Three principal alternatives for the reprocessing of the Slick Rock tailings were examined: heap leaching; treatment at an existing mill; and reprocessing at a new conventional mill constructed for tailings reprocessing. The cost of the uranium recovered would be over $800/lb of U 3 O 8 whether by conventional or heap leach plant processes. The spot market price for uranium was $25/lb early in 1981. Therefore, reprocessing the tailings for uranium recovery is not economically attractive at present, nor for the foreseeable future

Support to other nuclear waste disposal programmes considering clay as a potential host rock

International Nuclear Information System (INIS)

Volckaert, G.

2009-01-01

SCK-CEN started to study the Boom Clay as potential host rock for nuclear waste disposal in 1974. Since then, SCK-CEN has been involved in other international projects studying clay as potential host rock in order to get a broader support for disposal in clay and to acquire broader insight in clay behaviour. Besides Belgium, France and Switzerland are currently investigating clay formations as potential host rock for the disposal of radioactive waste. In the Netherlands, clay formations have always been considered as an alternative to disposal in salt. The general interest in clays is increasing: in Germany and The United Kingdom, it was decided a few years ago that besides respectively salt and crystalline rock also clays need to be evaluated. In Eastern and Central Europe, the Slovak republic and Lithuania consider both clay and granite as possible host rocks for spent fuel while in Russia recently a project was started to study the possible disposal of low and medium level waste in a clay formation in the Leningrad area. Within the EC research and development framework programs and the OECD/NEA Clay Club, collaborations were developed between countries studying clay and with a strong involvement of SCK-CEN. The collaboration with the Eastern and Central European countries is supported through the support programme of the Belgian Ministry of Economic affairs. The objectives of these co-operations are to deliver expert services to other nuclear waste disposal programs considering clay as host rock; to to acquire broader international recognition of our expertise and support for the development of nuclear waste disposal in clay; to get a broader insight in the properties and behaviour of clays

Preoperational assessment of solute release from waste rock at proposed mining operations

International Nuclear Information System (INIS)

Lapakko, Kim A.

2015-01-01

Highlights: • Modeling to estimate solute release from waste rock at proposed mines is described. • Components of the modeling process are identified and described. • Modeling inputs required are identified and described. • Examples of data generated and their application are presented. • Challenges inherent to environmental review are identified. - Abstract: Environmental assessments are conducted prior to mineral development at proposed mining operations. Among the objectives of these assessments is prediction of solute release from mine wastes projected to be generated by the proposed mining and associated operations. This paper provides guidance to those engaged in these assessments and, in more detail, provides insights on solid-phase characterization and application of kinetic test results for predicting solute release from waste rock. The logic guiding the process is consistent with general model construction practices and recent publications. Baseline conditions at the proposed site are determined and a detailed operational plan is developed and imposed upon the site. Block modeling of the mine geology is conducted to identify the mineral assemblages present, their masses and compositional variations. This information is used to select samples, representative of waste rock to be generated, that will be analyzed and tested to describe characteristics influencing waste rock drainage quality. The characterization results are used to select samples for laboratory dissolution testing (kinetic tests). These tests provide empirical data on dissolution of the various mineral assemblages present as waste rock. The data generated are used, in conjunction with environmental conditions, the proposed method of mine waste storage, and scientific and technical principles, to estimate solute release rates for the operational scale waste rock. Common concerns regarding waste rock are generation of acidic drainage and release of heavy metals and sulfate. Key solid

Geotechnical assessment and instrumentation needs for nuclear waste isolation in crystalline and argillaceous rocks

International Nuclear Information System (INIS)

1979-01-01

To evaluate the state-of-the-art, research needs, and research priorities related to waste disposal in largely impermeable rocks, scientists and engineers working on geologic aspects of nuclear waste disposal were brought together. This report and recommendations are the proceedings from that symposium. Three panels were organized on rock properties, fracture hydrology, and geochemistry. Panel discussions and recommendations are presented

Brooks under colliery heaps in the Walloon Region

Energy Technology Data Exchange (ETDEWEB)

Lardinois, J.P. [IGRETEC, Charleroi (Belgium); Flamion, B. [Mines et Geologie, Dir. Generale des Ressources Naturelles et de l' Environnement. Dir. des Eaux Souterraines, Jambes (Belgium); Zech, Y. [Universite Catholique de Louvain, Unite de Genie civil, Louvain-La-Neuve (Belgium)

2005-07-01

Several studies are presently under progress in the Walloon Region so as to assess the long term environmental impact caused by the closing of coal mines. Among the effects on water resources management, mining wastes deposits in the major bed of small rivers becomes a concern since the lack of maintenance of the works leads to difficulties of drainage in period of storm and to situations at risk for the vicinity. A first characterization carried out by the IGRETEC at the request of the Walloon Region leads to the selection of nine spoil heaps for more detailed investigations. The purpose is to update the administrative data by establishing the profile and cross sections of the works, to collect hydrological data and to evaluate measures to be proposed according to the risks and to the dimensioning of the works. The in situ investigations called upon specialized speleologists and the use of video cameras. (authors)

Brooks under colliery heaps in the Walloon Region

International Nuclear Information System (INIS)

Lardinois, J.P.; Flamion, B.; Zech, Y.

2005-01-01

Several studies are presently under progress in the Walloon Region so as to assess the long term environmental impact caused by the closing of coal mines. Among the effects on water resources management, mining wastes deposits in the major bed of small rivers becomes a concern since the lack of maintenance of the works leads to difficulties of drainage in period of storm and to situations at risk for the vicinity. A first characterization carried out by the IGRETEC at the request of the Walloon Region leads to the selection of nine spoil heaps for more detailed investigations. The purpose is to update the administrative data by establishing the profile and cross sections of the works, to collect hydrological data and to evaluate measures to be proposed according to the risks and to the dimensioning of the works. The in situ investigations called upon specialized speleologists and the use of video cameras. (authors)

Overview of the waste/barrier/rock interactions program of the basalt waste isolation project

International Nuclear Information System (INIS)

Salter, P.F.; Burnell, J.R.; Lane, D.L.

1986-01-01

The waste package waste/barrier/rock interactions testing program of the Basalt Waste Isolation Project is designed to assess the interactions between nuclear waste forms, other waste package components, and the environment in order to evaluate long-term waste package isolation (radionuclide release) behavior. The program involves reacting fully radioactive waste forms with combinations of steel or copper container material and basalt/bentonite packing material in site-specific ground water under anticipated repository conditions to obtain the steady state radionuclide concentrations required to predictively model waste package radionuclide concentrations required to predictively model waste package radionuclide releases. Both static and flow-through autoclaves are being used in the test program to determine radionuclide concentrations as a function of time and groundwater flow rate, and to evaluate the solid phase and water chemistry changes that control those concentrations. This test program, when combined with project hydrologic and geochemical testing and modeling efforts, and natural analog studies, provides the information required to evaluate long-term radionuclide mobility within a waste package emplaced in a basalt repository

Geotechnical modeling of high-level nuclear waste disposal by rock melting

International Nuclear Information System (INIS)

Heuze, F.E.

1981-12-01

A new strategy has been developed for the geotechnical modeling of nuclear waste disposal by rock melting (DRM). Three seeparate tasks were performed to reach this objective: a review of the four scenarios which have been proposed for DRM, to date; an evaluation of computer-based numerical models which could be used to analyze the mechanical, thermal, and hydraulic processes involved in DRM; and a critical review of rock mass properties which are relevant to the design and safety of waste disposal by rock melting. It is concluded that several geotechnical aspects of DRM can be studied realistically with current state-of-the-art model capabilities and knowledge of material properties. The next step in the feasibility study of DRM should be a best-estimate calculation of the four cavity-melt and canister-burial concepts. These new analyses will indicate the most critical areas for subsequent research

Characterization of phosphorus leaching from phosphate waste rock in the Xiangxi River watershed, Three Gorges Reservoir, China.

Science.gov (United States)

Jiang, Li-Guo; Liang, Bing; Xue, Qiang; Yin, Cheng-Wei

2016-05-01

Phosphate mining waste rocks dumped in the Xiangxi River (XXR) bay, which is the largest backwater zone of the Three Gorges Reservoir (TGR), are treated as Type I industry solid wastes by the Chinese government. To evaluate the potential pollution risk of phosphorus leaching from phosphate waste rocks, the phosphorus leaching behaviors of six phosphate waste rock samples with different weathering degrees under both neutral and acidic conditions were investigated using a series of column leaching experiments, following the Method 1314 standard of the US EPA. The results indicate that the phosphorus release mechanism is solubility-controlled. Phosphorus release from waste rocks increases as pH decreases. The phosphorus leaching concentration and cumulative phosphorus released in acidic leaching conditions were found to be one order of magnitude greater than that in neutral leaching conditions. In addition, the phosphorus was released faster during the period when environmental pH turned from weak alkalinity to slight acidity, with this accelerated release period appearing when L/S was in the range of 0.5-2.0 mL/g. In both neutral and acidic conditions, the average values of Total Phosphorus (TP), including orthophosphates, polyphosphates and organic phosphate, leaching concentration exceed the availability by regulatory (0.5 mg/L) in the whole L/S range, suggesting that the phosphate waste rocks stacked within the XXR watershed should be considered as Type II industry solid wastes. Therefore, the phosphate waste rocks deposited within the study area should be considered as phosphorus point pollution sources, which could threaten the adjacent surface-water environment. Copyright © 2016 Elsevier Ltd. All rights reserved.

Reduction of acid rock drainage using steel slag in cover systems over sulfide rock waste piles.

Science.gov (United States)

de Almeida, Rodrigo Pereira; Leite, Adilson do Lago; Borghetti Soares, Anderson

2015-04-01

The extraction of gold, coal, nickel, uranium, copper and other earth-moving activities almost always leads to environmental damage. In metal and coal extraction, exposure of sulfide minerals to the atmosphere leads to generation of acid rock drainage (ARD) and in underground mining to acid mine drainage (AMD) due to contamination of infiltrating groundwater. This study proposes to develop a reactive cover system that inhibits infiltration of oxygen and also releases alkalinity to increase the pH of generated ARD and attenuate metal contaminants at the same time. The reactive cover system is constructed using steel slag, a waste product generated from steel industries. This study shows that this type of cover system has the potential to reduce some of the adverse effects of sulfide mine waste disposal on land. Geochemical and geotechnical characterization tests were carried out. Different proportions of sulfide mine waste and steel slag were studied in leachate extraction tests. The best proportion was 33% of steel slag in dry weight. Other tests were conducted as follows: soil consolidation, saturated permeability and soil water characteristic curve. The cover system was numerically modeled through unsaturated flux analysis using Vadose/w. The solution proposed is an oxygen transport barrier that allows rain water percolation to treat the ARD in the waste rock pile. The results showed that the waste pile slope is an important factor and the cover system must have 5 m thickness to achieve an acceptable effectiveness. © The Author(s) 2015.

Heap leaching of Cu contaminated soil with [S,S]-EDDS in a closed process loop

International Nuclear Information System (INIS)

Finzgar, Neza; Zumer, Alenka; Lestan, Domen

2006-01-01

Heap leaching of Cu contaminated soil (412 ± 11 mg kg -1 ) with 5 mmol kg -1 ethylenediamine disuccinate [S,S]-EDDS as a chelator was tested in a laboratory-scale soil column study. The washing solution was recycled in a closed process loop after microbial (using a microbially active permeable bed, composed of substrate and absorbent) and oxidative chemical (using combined ozonation and UV irradiation) degradation of metal-[S,S]-EDDS complexes and retention of released Cu on a commercial absorbent Slovakite. Heap leaching using the permeable bed removed 25.5 ± 3.6% of initial total Cu from the soil. Ozone/UV treatment of the [S,S]-EDDS washing solution removed much more, 47.5 ± 7.4%, of Cu. Both methods yielded a clear and colorless final (waste) washing solution, with 7.0 ± 10.0 and 2.6 ± 0.7 mg L -1 Cu (permeable bed and ozone/UV method, respectively). The results of our study indicate that chemical treatment of chelator washing solution with ozone/UV in a closed process loop could lead to the development of a new, efficient and environmentally safe remediation method with controllable Cu emissions

Effect of heterogeneity and anisotropy related to the construction method on transfer processes in waste rock piles.

Science.gov (United States)

Lahmira, Belkacem; Lefebvre, René; Aubertin, Michel; Bussière, Bruno

2016-01-01

Waste rock piles producing acid mine drainage (AMD) are partially saturated systems involving multiphase (gas and liquid) flow and coupled transfer processes. Their internal structure and heterogeneous properties are inherited from their wide-ranging material grain sizes, their modes of deposition, and the underlying topography. This paper aims at assessing the effect of physical heterogeneity and anisotropy of waste rock piles on the physical processes involved in the generation of AMD. Generic waste rock pile conditions were represented with the numerical simulator TOUGH AMD based on those found at the Doyon mine waste rock pile (Canada). Models included four randomly distributed material types (coarse, intermediate, fine and very fine-grained). The term "randomly" as used in this study means that the vertical profile and spatial distribution of materials in waste rock piles (internal structure) defy stratigraphy principles applicable to natural sediments (superposition and continuity). The materials have different permeability and capillary properties, covering the typical range of materials found in waste rock piles. Anisotropy with a larger horizontal than vertical permeability was used to represent the effect of pile construction by benches, while the construction by end-dumping was presumed to induce a higher vertical than horizontal permeability. Results show that infiltrated precipitation preferentially flows in fine-grained materials, which remain almost saturated, whereas gas flows preferentially through the most permeable coarse materials, which have higher volumetric gas saturation. Anisotropy, which depends on pile construction methods, often controls global gas flow paths. Construction by benches favours lateral air entry close to the pile slope, whereas end-dumping leads to air entry from the surface to the interior of the pile by secondary gas convection cells. These results can be useful to construct and rehabilitate waste rock piles to minimize

Oxygen influx and geochemistry of percolate water from reactive mine waste rock underlying a sloping channelled soil cover

Energy Technology Data Exchange (ETDEWEB)

Song Qing, E-mail: qsong3@uwo.ca [Geotechnical Research Center, Department of Civil and Environmental Engineering, University of Western Ontario, 1151 Richmond Street, London, ON, N6A 5B9 (Canada); Yanful, Ernest K., E-mail: eyanful@eng.uwo.ca [Geotechnical Research Center, Department of Civil and Environmental Engineering, University of Western Ontario, 1151 Richmond Street, London, ON, N6A 5B9 (Canada)

2011-05-15

Research Highlights: > A channelled cover with preferential flow can still mitigate ARD to some extent. > Oxygen ingress was more sensitive to the location of the channel than to K{sub s}. > The channel in the barrier layer was a major passage for O{sub 2} ingress. > Actual flushing was an important factor when estimating O{sub 2} decay coefficient. - Abstract: An ideal engineered soil cover can mitigate acid rock drainage (ARD) by limiting water and gaseous O{sub 2} ingress into an underlying waste rock pile. However, the barrier layer in the soil cover almost invariably tends to develop cracks or fractures after placement. These cracks may change water flow and O{sub 2} transport in the soil cover and decrease performance in the long run. The present study employed a 10-cm-wide sand-filled channel installed in a soil barrier layer (silty clay) to model the aggregate of cracks or fractures that may be present in the cover. The soil cover had a slope of 20%. Oxygen transport through the soil cover and oxidation of the underlying waste rock were investigated and compared to a controlled column test with bare waste rock (without soil cover). Moreover, gaseous O{sub 2} transport in the soil cover with channel and its sensitivity to channel location as well as the influence of the saturated hydraulic conductivity of the channel material were modeled using the commercial software VADOSE/W. The results indicted that the waste rock underlying the soil cover with channel had a lower oxidation rate than the waste rock without cover because of reduced O{sub 2} ingress and water flushing in the soil cover with channel, which meant a partial soil cover might still be effective to some extent in reducing ARD generation. Gaseous O{sub 2} ingress into the covered waste rock was more sensitive to the channel location than to the saturated hydraulic conductivity of the material filling the channel. Aqueous equilibrium speciation modeling and scanning electron microscopy with energy

A review of acid drainage from waste rock dumps and mine sites (Australian and Scandinavia)

International Nuclear Information System (INIS)

Harries, J.R.

1990-05-01

This report reviews the literature from Australia and Scandinavia on acid drainage from pyritic waste rock dumps with an emphasis on measurements and theory of processes that control the rage of oxidation and the release of pollutants. Conditions within waste rock dumps have been measured at several mine sites and a range of rehabilitation treatments have been tried to reduce the release of pollutants. A number of models have been proposed to calculate air flow, water transport and geochemistry. The data and experience at the mine sites are compared with predictions of the models. Details of Australian and Swedish mine sites where waste rock is a source of acid drainage are described in the Appendices. 92 refs., 2 tabs., 10 figs

Commercial experimental on bacteria heap leaching of uranium ore from Caotaobei mining area in Ganzhou uranium mine

International Nuclear Information System (INIS)

Fan Baotuan; Meng Yunsheng; Liu Jian; Xiao Jinfeng; Chen Sencai; Cao Jianbo; Wu Yichang; Liu Chengwu

2002-01-01

The author presents the result of commercial experiment on bacteria heap leaching of uranium ore from Caotaobei mining area in Ganzhou Uranium Mine and summarizes the heap situation, installation of spraying and sprinkling devices, and operation management of continuous oxidizing tank of bio-membrane. The leaching rate is 92.95% and 91.88% respectively by liquid and residue measurement during 85 d bacterial leaching experiment. The acid consumption is 2.1% and the total liquid-solid ratio is 2.9 m 3 /t. Compared with conventional heap leaching, the time of bacteria heap leaching shorted about 75 d, the acid consumption reduced by 0.35% and the leaching rate improved by 2%. It is an optimize plan to reform the heap leaching technology for Caotaobei ore

Uranium production and environmental restoration at Priargunsky Centre (Russian Federation)

International Nuclear Information System (INIS)

Shatalov, V.V.; Boitsov, A.V.; Nikolsky, A.L.; Chernigov, V.G.; Ovseichuk, V.A.

2002-01-01

The state enterprise 'Priargunsky Mining and Chemical Production Association' (PPGHO) is the only active uranium production centre in Russia in last decade. Mining has been operated since 1968 by two open pits and four underground mines. It is based on resources of 19 volcanic-type deposits of Streltsovsk U-ore region situated at the area of 150 km 2 . Milling and processing has been carried out since 1974 at the local hydrometallurgical plant. Since the mid 1980s, limited amount of uranium is produced by heap and block leaching methods. High level of total production marks PPGHO as one of the outstanding uranium production centers worldwide. Significant amount of solid, liquid and gas wastes have been generated for more than 30 years. The principal environmental contamination comes from waste rock piles, mine water and tailing ponds. Liquid waste seepage through tailing pond bed can essentially contaminate underground waters. The principal environmental remediation activities are: waste rock dumps and open pits rehabilitation; waste rock utilization for industrial needs; heap and block leaching mining development, strengthening dam bodies and construction intercepting wells below the tailing pond dam, hydrogeological monitoring, upgrade of mine water treatment unit. Waste is being managed by the environmental service team of PPGHO. Environmental restoration activities, including rehabilitation of the territories and waste utilization, are implemented gradually in line with decommissioning of enterprise's particular facilities. (author)

Geotechnical site assessment for underground radioactive waste disposal in rock

International Nuclear Information System (INIS)

Hudson, J.A.

1986-05-01

This report contains a state-of-the-art review of the geotechnical assessment of Land 3 and Land 4 repository sites (at 100 - 300 m depth in rock) for intermediate level radioactive waste disposal. The principles established are also valid for the disposal of low and high level waste in rock. The text summarizes the results of 21 DoE research contract reports, firstly 'in series' by providing a technical review of each report and then 'in parallel' by considering the current state of knowledge in the context of the subjects in an interaction matrix framework. 1214 references are cited. It is concluded that four further research projects are required for site assessment procedures to be developed or confirmed. These are coupled modelling, mechanical properties, water flow and establishment of 2 phase site assessment procedures. (author)

Creep in crystalline rock with application to high level nuclear waste repository

International Nuclear Information System (INIS)

Eloranta, P.; Simonen, A.

1992-06-01

The time-dependent strength and deformation properties of hard crystalline rock are studied. Theoretical models defining the phenomena which can effect these properties are reviewed. The time- dependent deformation of the openings in the proposed nuclear waste repository is analysed. The most important factors affecting the subcritical crack growth in crystalline rock are the stress state, the chemical environment, temperature and microstructure of the rock. There are several theoretical models for the analysis of creep and cyclic fatigue: deformation diagrams, rheological models thermodynamic models, reaction rate models, stochastic models, damage models and time-dependent safety factor model. They are defective in describing the three-axial stress condition and strength criteria. In addition, the required parameters are often too difficult to determine with adequate accuracy. Therefore these models are seldom applied in practice. The effect of microcrack- driven creep on the stability of the work shaft, the emplacement tunnel and the capsulation hole of a proposed nuclear waste repository was studied using a numerical model developed by Atomic Energy of Canada Ltd. According to the model, the microcrack driven creep progresses very slowly in good quality rock. Poor rock quality may accelerate the creep rate. The model is very sensitive to the properties of the rock and secondary stress state. The results show that creep causes no stability problems on excavations in good rock. The results overestimate the effect of the creep, because the analysis omitted the effect of support structures and backfilling

Deviations in the Zipf and Heaps laws in natural languages

Science.gov (United States)

Bochkarev, Vladimir V.; Lerner, Eduard Yu; Shevlyakova, Anna V.

2014-03-01

This paper is devoted to verifying of the empirical Zipf and Hips laws in natural languages using Google Books Ngram corpus data. The connection between the Zipf and Heaps law which predicts the power dependence of the vocabulary size on the text size is discussed. In fact, the Heaps exponent in this dependence varies with the increasing of the text corpus. To explain it, the obtained results are compared with the probability model of text generation. Quasi-periodic variations with characteristic time periods of 60-100 years were also found.

Deviations in the Zipf and Heaps laws in natural languages

International Nuclear Information System (INIS)

Bochkarev, Vladimir V; Lerner, Eduard Yu; Shevlyakova, Anna V

2014-01-01

This paper is devoted to verifying of the empirical Zipf and Hips laws in natural languages using Google Books Ngram corpus data. The connection between the Zipf and Heaps law which predicts the power dependence of the vocabulary size on the text size is discussed. In fact, the Heaps exponent in this dependence varies with the increasing of the text corpus. To explain it, the obtained results are compared with the probability model of text generation. Quasi-periodic variations with characteristic time periods of 60-100 years were also found

Geochemical tracing and hydrogeochemical modelling of water-rock interactions during salinization of alluvial groundwater (Upper Rhine Valley, France)

Energy Technology Data Exchange (ETDEWEB)

Lucas, Y., E-mail: yann.lucas@eost.u-strasbg.fr [Universite de Strasbourg et CNRS, Laboratoire d' Hydrologie et de Geochimie de Strasbourg, Ecole et Observatoire des Sciences de la Terre, 1, rue Blessig, 67084 Strasbourg Cedex (France); Schmitt, A.D., E-mail: anne-desiree.schmitt@univ-fcomte.fr [Universite de Strasbourg et CNRS, Laboratoire d' Hydrologie et de Geochimie de Strasbourg, Ecole et Observatoire des Sciences de la Terre, 1, rue Blessig, 67084 Strasbourg Cedex (France)] [Universite de Franche-Comte et CNRS-UMR 6249, Chrono-Environnement, 16, Route de Gray, 25030 Besancon Cedex (France); Chabaux, F., E-mail: francois.chabaux@eost.u-strasbg.fr [Universite de Strasbourg et CNRS, Laboratoire d' Hydrologie et de Geochimie de Strasbourg, Ecole et Observatoire des Sciences de la Terre, 1, rue Blessig, 67084 Strasbourg Cedex (France); Clement, A.; Fritz, B. [Universite de Strasbourg et CNRS, Laboratoire d' Hydrologie et de Geochimie de Strasbourg, Ecole et Observatoire des Sciences de la Terre, 1, rue Blessig, 67084 Strasbourg Cedex (France); Elsass, Ph. [BRGM, GEODERIS, 1, rue Claude Chappe, 57070 Metz (France); Durand, S. [Universite de Strasbourg et CNRS, Laboratoire d' Hydrologie et de Geochimie de Strasbourg, Ecole et Observatoire des Sciences de la Terre, 1, rue Blessig, 67084 Strasbourg Cedex (France)

2010-11-15

Research highlights: {yields} Major and trace elements along with strontium and uranium isotopic ratios show that groundwater geochemical characteristics along the saline plumes cannot reflect a conservative mixing. {yields} A coupled hydrogeochemical model demonstrates that cationic exchange between alkalis from polluted waters and alkaline-earth elements from montmorillonite present in the host rock of the aquifer is the primary process. {yields} The model requires only a small amount of montmorillonite. {yields} It is necessary to consider the pollution history to explain the important chloride, sodium and calcium concentration modifications. {yields} The model shows that the rapidity of the cationic exchange reactions insures a reversibility of the cation fixation on clays in the aquifer. - Abstract: In the southern Upper Rhine Valley, groundwater has undergone intensive saline pollution caused by the infiltration of mining brines, a consequence of potash extraction carried out during the 20th century. Major and trace elements along with Sr and U isotopic ratios show that groundwater geochemical characteristics along the saline plumes cannot reflect conservative mixing between saline waters resulting from the dissolution of waste heaps and one or more unpolluted end-members. The results imply the occurrence of interactions between host rocks and polluted waters, and they suggest that cationic exchange mechanisms are the primary controlling process. A coupled hydrogeochemical model has been developed with the numerical code KIRMAT, which demonstrates that cationic exchange between alkalis from polluted waters and alkaline-earth elements from montmorillonite present in the host rock of the aquifer is the primary process controlling the geochemical evolution of the groundwater. The model requires only a small amount of montmorillonite (between 0.75% and 2.25%), which is in agreement with the observed mineralogical composition of the aquifer. The model also proves

Event heap: a coordination infrastructure for dynamic heterogeneous application interactions in ubiquitous computing environments

Science.gov (United States)

Johanson, Bradley E.; Fox, Armando; Winograd, Terry A.; Hanrahan, Patrick M.

2010-04-20

An efficient and adaptive middleware infrastructure called the Event Heap system dynamically coordinates application interactions and communications in a ubiquitous computing environment, e.g., an interactive workspace, having heterogeneous software applications running on various machines and devices across different platforms. Applications exchange events via the Event Heap. Each event is characterized by a set of unordered, named fields. Events are routed by matching certain attributes in the fields. The source and target versions of each field are automatically set when an event is posted or used as a template. The Event Heap system implements a unique combination of features, both intrinsic to tuplespaces and specific to the Event Heap, including content based addressing, support for routing patterns, standard routing fields, limited data persistence, query persistence/registration, transparent communication, self-description, flexible typing, logical/physical centralization, portable client API, at most once per source first-in-first-out ordering, and modular restartability.

Basic rock properties for the thermo-hydro-mechanical analysis of a high-level radioactive waste repository

Energy Technology Data Exchange (ETDEWEB)

Kim, Jhin Wung; Kang, Chul Hyung

1999-04-01

Deep geological radioactive waste disposal is generally based on the isolation of the waste from the biosphere by multiple barriers. The host rock is one of these barriers which should provide a stable mechanical and chemical environment for the engineered barriers. In the evaluation of the safety of the high-level radioactive waste disposal systems, an important part of the safety analysis is an assessment of the coupling or interaction between thermal, hydrological, and mechanical effects. In order to do this assessment, adequate data on the characteristics of different host rocks are necessary. The properties of the rock and rock discontinuity are very complex and their values vary in a wide range. The accuracy of the result of the assessment depends on the values of these properties used. The present study is an attempt to bring together and condense data for the basic properties of various rock masses, which are needed in the thermo-hydro-mechanical analysis for the deep geological radioactive waste repository. The testing and measurement methods for these basic properties are also presented. Domestic data for deep geological media should be supplemented in the future, due to the insufficiency and the lack of accuracy of the data available at present. (author). 28 refs., 21 figs.

Basic rock properties for the thermo-hydro-mechanical analysis of a high-level radioactive waste repository

International Nuclear Information System (INIS)

Kim, Jhin Wung; Kang, Chul Hyung

1999-04-01

Deep geological radioactive waste disposal is generally based on the isolation of the waste from the biosphere by multiple barriers. The host rock is one of these barriers which should provide a stable mechanical and chemical environment for the engineered barriers. In the evaluation of the safety of the high-level radioactive waste disposal systems, an important part of the safety analysis is an assessment of the coupling or interaction between thermal, hydrological, and mechanical effects. In order to do this assessment, adequate data on the characteristics of different host rocks are necessary. The properties of the rock and rock discontinuity are very complex and their values vary in a wide range. The accuracy of the result of the assessment depends on the values of these properties used. The present study is an attempt to bring together and condense data for the basic properties of various rock masses, which are needed in the thermo-hydro-mechanical analysis for the deep geological radioactive waste repository. The testing and measurement methods for these basic properties are also presented. Domestic data for deep geological media should be supplemented in the future, due to the insufficiency and the lack of accuracy of the data available at present. (author). 28 refs., 21 figs

Hydrological and thermal issues concerning a nuclear waste repository in fractured rocks

International Nuclear Information System (INIS)

Wang, J.S.Y.

1991-12-01

The characterization of the ambient conditions of a potential site and the assessment of the perturbations induced by a nuclear waste repository require hydrological and thermal investigations of the geological formations at different spatial and temporal scales. For high-level wastes, the near-field impacts depend on the heat power of waste packages and the far-field long-term perturbations depend on the cumulative heat released by the emplaced wastes. Surface interim storage of wastes for several decades could lower the near-field impacts but would have relatively small long-term effects if spent fuels were the waste forms for the repository. One major uncertainty in the assessment of repository impacts is from the variation of hydrological properties in heterogeneous media, including the effects of fractures as high-permeability flow paths for containment migration. Under stress, a natural fracture cannot be represented by the parallel plate model. The rock surface roughness, the contact area, and the saturation state in the rock matrix could significantly change the fracture flow. In recent years, the concern of fast flow through fractures in saturated media has extended to the unsaturated zones. The interactions at different scales between fractures and matrix, between fractured matrix unites and porous units, and between formations and faults are discussed

An analysis of the heap construction by long hole blasting for in-situ leaching of blasted ore

International Nuclear Information System (INIS)

Yang Shijiao

1999-01-01

The author establishes specific requirements for heap construction by blasting on the basis of the mechanism for in situ leaching of blasted ore, analyses the feasibility of heap construction by long hole blasting, selection of the blast plan and the relevant technological problems, and gives a case of heap construction by long hole blasting in Renhua uranium mine

Technical support for GEIS: radioactive waste isolation in geologic formations. Volume 5. Baseline rock properties-granite

International Nuclear Information System (INIS)

1978-04-01

This volume, Y/OWI/TM-36/5, Baseline Rock Properties--Granite, is one of a 23-volume series, ''Technical Support for GEIS: Radioactive Waste Isolation in Geologic Formations, Y/OWI/TM-36'' which supplements a ''Contribution to Draft Generic Environmental Impact Statement on Commercial Waste Management: Radioactive Waste Isolation in Geologic Formations, Y/OWI/TM-44.'' The series provides a more complete technical basis for the preconceptual designs, resource requirements, and environmental source terms associated with isolating commercial LWR wastes in underground repositories in salt, granite, shale and basalt. Wastes are considered from three fuel cycles: uranium and plutonium recycling, no recycling of spent fuel and uranium-only recycling. This report, on the rock properties of typical granites, includes an evaluation of the various test results reported in the literature. Firstly, a literature survey was made in order to obtain a feel for the range of rock properties encountered. Then, granites representative of different geologic ages and from different parts of the United States were selected and studied in further detail. Some of the special characteristics of granite, such as anisotropy, creep and weathering were also investigated. Lastly, intact properties for a typical granite were selected and rock mass properties were derived using appropriate correction factors

Reagents and fractions impact on sulphide ore heap bioleaching at Smolnik mine

Science.gov (United States)

Oros, L. M.; Zavada, J.

2017-10-01

Mine Smolnik is one of the oldest sulphide ore mines in Europe and it is also an important part of bioleaching development. This paper follows previous attempts to extract residual metals from nearby heaps via variations in bioleaching reagents with regard to recent findings and needs in the related industry. Furthermore, economic and process relations between reagents and chosen heap fractions were also investigated in this case study.

Transient response in granular bounded heap flows

Science.gov (United States)

Xiao, Hongyi; Ottino, Julio M.; Lueptow, Richard M.; Umbanhowar, Paul B.

2017-11-01

Heap formation, a canonical granular flow, is common in industry and is also found in nature. Here, we study the transition between steady flow states in quasi-2D bounded heaps by suddenly changing the feed rate from one fixed value to another. During the transition, in both experiments and discrete element method simulations, an additional wedge of flowing particles propagates over the rising free surface. The downstream edge of the wedge - the wedge front - moves downstream with velocity inversely proportional to the square root of time. An additional longer duration transient process continues after the wedge front reaches the downstream wall. The transient flux profile during the entire transition is well modeled by a diffusion-like equation derived from local mass balance and a local linear relation between the flux and the surface slope. Scalings for the transient kinematics during the flow transitions are developed based on the flux profiles. Funded by NSF Grant CBET-1511450.

Proceedings of the symposium on the management and rehabilitation of waste rock dumps

International Nuclear Information System (INIS)

Riley, S.R.; Waggitt, P.W.; McQuade, C.

1993-01-01

Waste rock management and rehabilitation are issues with economic, legal and scientific ramifications which may have significant effects on the viability and profitability of mining operations. Through this symposium the Office of the Supervising Scientist and the Australasian Institute of Mining and Metallurgy (Darwin branch) brought together five key disciplines essential for the efficient design and long term management of waste rock dump, planning and economics, hydrology, geochemistry, biology and geotechnics. The symposium was targeted at industry personnel who make the decisions in design planning and day-to-day management. Two out of the 13 papers have been separately indexed

Characterization of the material produced using marble waste and reagents aiminig production of rock wool

International Nuclear Information System (INIS)

Rodrigues, Girley Ferreira; Espinosa, Denise Crocce Romano; Tenorio, Jorge Alberto Soares; Alves, Joner Oliveira

2010-01-01

The aim of this work was to characterize materials produced from the mixture of marble waste and chemical reagents. The materials were homogenized, melted and cooled in order to obtain materials with similar characteristics of rock wools. The batch was poured in a water-filled recipient and also in a Herty viscometer at three temperatures. Samples of produced materials were characterized by X-ray diffraction, scanning electron microscopy and differential thermal analysis. Results of this study indicate that it is possible the incorporation of marble waste in the production process of rock wool, replacing approximately 15% of the raw material used to fabricate this material. This process represents a technological breakthrough since it allows the reuse of marble waste, and also represents a possible decrease in rock wool production cost, which is a material with a growing market as thermo acoustic insulator. (author)

Exploring the techno-economic feasibility of mine rock waste utilisation in road works: The case of a mining deposit in Ghana.

Science.gov (United States)

Agyeman, Stephen; Ampadu, Samuel I K

2016-02-01

Mine rock waste, which is the rock material removed in order to access and mine ore, is free from gold processing chemical contaminants but presents a significant environmental challenge owing to the large volumes involved. One way of mitigating the environmental and safety challenges posed by the large volume of mine rock waste stockpiled in mining communities is to find uses of this material as a substitute for rock aggregates in construction. This article reports on a study conducted to evaluate the engineering properties of such a mine deposit to determine its suitability for use as road pavement material. Samples of mine rock waste, derived from the granitic and granodioritic intrusive units overlying the gold-bearing metavolcanic rock and volcano-clastic sediments of a gold mining area in Ghana, were obtained from three mine rock waste disposal facilities and subjected to a battery of laboratory tests to determine their physical, mechanical, geotechnical, geometrical and durability properties. The overall conclusion was that the mine rock waste met all the requirements of the Ghana Ministry of Transportation specification for use as aggregates for crushed rock subbase, base and surface dressing chippings for road pavements. The recommendation is to process it into the required sizes for the various applications. © The Author(s) 2015.

Review of potential host rocks for radioactive waste disposal in the Piedmont Province of South Carolina

International Nuclear Information System (INIS)

Secor, D.T. Jr.

1980-10-01

This report reviews the geology of the Piedmont Province of South Carolina with the aim of designating rock units favorable for field exploration for a potential underground repository for the storage of radioactive waste. Most of the rocks in the South Carolina Piedmont are metamorphosed sedimentary volcanic or igneous rocks that have experienced at least one episode of strong deformation. As a consequence of this deformation, they have irregular shapes, making it difficult to predict their subsurface extent. In evaluating the suitability of the rock units for radioactive waste storage, certain criteria were found to be particularly useful. The requirements that the storage site be located in a large volume of homogeneous, impermeable, relatively unfractured rock was the most important criteria in eliminating most of the Piedmont rock units for consideration as field study areas. Six large late- to post-tectonic igneous plutons (Winnsboro, Liberty Hill, Ogden, Newberry, Lowrys, and Bald Rock) are recommended as field study areas

Damage-plasticity model of the host rock in a nuclear waste repository

Energy Technology Data Exchange (ETDEWEB)

Koudelka, Tomáš; Kruis, Jaroslav, E-mail: kruis@fsv.cvut.cz [Department of Mechanics, Faculty of Civil Engineering, Czech Technical University in Prague, Thákurova 7, 166 29 Prague (Czech Republic)

2016-06-08

The paper describes damage-plasticity model for the modelling of the host rock environment of a nuclear waste repository. Radioactive Waste Repository Authority in Czech Republic assumes the repository to be in a granite rock mass which exhibit anisotropic behaviour where the strength in tension is lower than in compression. In order to describe this phenomenon, the damage-plasticity model is formulated with the help of the Drucker-Prager yield criterion which can be set to capture the compression behaviour while the tensile stress states is described with the help of scalar isotropic damage model. The concept of damage-plasticity model was implemented in the SIFEL finite element code and consequently, the code was used for the simulation of the Äspö Pillar Stability Experiment (APSE) which was performed in order to determine yielding strength under various conditions in similar granite rocks as in Czech Republic. The results from the performed analysis are presented and discussed in the paper.

Extremophiles in Mineral Sulphide Heaps: Some Bacterial Responses to Variable Temperature, Acidity and Solution Composition

Directory of Open Access Journals (Sweden)

Helen R. Watling

2015-07-01

Full Text Available In heap bioleaching, acidophilic extremophiles contribute to enhanced metal extraction from mineral sulphides through the oxidation of Fe(II and/or reduced inorganic sulphur compounds (RISC, such as elemental sulphur or mineral sulphides, or the degradation of organic compounds derived from the ore, biota or reagents used during mineral processing. The impacts of variable solution acidity and composition, as well as temperature on the three microbiological functions have been examined for up to four bacterial species found in mineral sulphide heaps. The results indicate that bacteria adapt to sufficiently high metal concentrations (Cu, Ni, Co, Zn, As to allow them to function in mineral sulphide heaps and, by engaging alternative metabolic pathways, to extend the solution pH range over which growth is sustained. Fluctuating temperatures during start up in sulphide heaps pose the greatest threat to efficient bacterial colonisation. The large masses of ores in bioleaching heaps mean that high temperatures arising from sulphide oxidation are hard to control initially, when the sulphide content of the ore is greatest. During that period, mesophilic and moderately thermophilic bacteria are markedly reduced in both numbers and activity.

Site-specific evaluation of safety issues for high-level waste disposal in crystalline rocks. Final report

Energy Technology Data Exchange (ETDEWEB)

Jobmann, M. (ed.) [DBE Technology GmbH, Peine (Germany)

2016-03-31

In the past, German research and development (R and D) activities regarding the disposal of radioactive waste, including spent nuclear fuel, focused mainly on domal rock salt because rock salt was the preferred host rock formation. In addition, generic R and D work regarding alternative host rocks (crystalline rocks and claystones) had been performed as well for a long time but with lower intensity. Around the year 2000, as a consequence of the moratorium on the Gorleben site, the Federal Government decided to have argillaceous rocks and crystalline rocks investigated in more detail. As Germany does not have any underground research and host rock characterization facilities, international cooperation received a high priority in the German R and D programme for high-level waste (HLW) disposal in order to increase the knowledge regarding alternative host rocks. Major cornerstones of the cooperation are joint projects and experiments conducted especially in underground research laboratories (URL) in crystalline rocks at the Grimsel Test Site (Switzerland) and the Hard Rock Laboratory (HRL) Aespoe(Sweden) and in argillaceous rocks at the URL Mont Terri (Switzerland) and Bure (France). In 2001, the topic of radioactive waste disposal was integrated into the agreement between the former Russian Ministry of Atomic Energy (Minatom, now Rosatom) and the German Ministry of Labor (BMWA), now Ministry of Economic Affairs and Energy (BMWi), on cooperation regarding R and D on the peaceful utilization of nuclear power (agreement on ''Wirtschaftlich-Technische Zusammenarbeit'' WTZ). The intention was to have a new and interesting opportunity for international R and D cooperation regarding HLW disposal in crystalline rocks and the unique possibility to perform site-specific work, to test the safety demonstration tools available, and to expand the knowledge to all aspects specific to these host rocks. Another motivation for joining this cooperation was the

Ni, Co, and Cr contents in the soil and in some plants of Dobsina asbestos heaps

Energy Technology Data Exchange (ETDEWEB)

Banasova, V

1978-01-01

Results of analyses of substrates of heaps after mining and working of asbestos as well as of two plants viz. Melilotus officinalis Lam. and Calamagrostis epigeios Roth. for Ni, Co and Cr. Ni and Co concentrations in the analyzed plants and heap substrates were found to be higher than in common soils and in plants growing at unsophisticated localities. The values ascertained are at the same time lower than in soils and plants on serpentines. There were very low Cr contents in substrates of the studied heaps. On the contrary, in both analyzed plant species Cr concentration was found to be much higher than in the investigated heap substrates. At that locality Melilotus officinalis and Calamagrostis epigeios appear to be concentrators of chromium.

New technology of bio-heap leaching uranium ore and its industrial application in Ganzhou uranium mine

International Nuclear Information System (INIS)

Fan Baotuan; Meng Yunsheng; Liu Jian; Meng Jin; Li Weicai; Xiao Jinfeng; Chen Sencai; Du Yuhai; Huang Bin

2006-10-01

Bioleaching mechanism of uranium ore is discussed. Incubation and selection of new strain, biomembrane oxidizing tank--a kind of new equipment for bacteria culture and oxidation regeneration of leaching agent are also introduced. The results of industrial experiment and industrial production are summarized. Compared with conventional heap leaching, bioleaching period and acid amount are reduced, oxidant and leaching agent are saved, and uranium concentration in leaching solution is increased. It is the first time to realize industrial production by bio-heap leaching in Chinese uranium mine. New equipment-biomembrane oxidizing tank give the basis of bio-heap leaching industrial application. Bio-heap leaching process is an effective technique to reform technique of uranium mine and extract massive low-content uranium ore in China. (authors)

The general solution of a Nim-heap game

Institute of Scientific and Technical Information of China (English)

宋林森; 卢澎涛

2010-01-01

As a combinatorial one,the game Nim turns out to be extremely useful in certain types of combinatorial game analysis.It has given the general solution of the game a Nim-heap game and the result has proved true.

Acceptance criteria for disposal of radioactive wastes in shallow ground and rock cavities

International Nuclear Information System (INIS)

1985-01-01

This document provides an overview of basic information related to waste acceptance criteria for disposal in shallow ground and rock cavity repositories, consisting of a discussion of acceptable waste types. The last item includes identification of those waste characteristics which may influence the performance of the disposal system and as such are areas of consideration for criteria development. The material is presented in a manner similar to a safety assessment. Waste acceptance criteria aimed at limiting the radiation exposure to acceptable levels are presented for each pathway. Radioactive wastes considered here are low-level radioactive wastes and intermediate-level radioactive wastes from nuclear fuel cycle operations and applications of radionuclides in research, medicine and industry

Release consequence analysis for a hypothetical geologic radioactive waste repository in hard rock

International Nuclear Information System (INIS)

1979-12-01

This report makes an evaluation of the long-term behaviour of the wastes placed in a hard rock repository. Impacts were analyzed for the seven reference fuel cycles of WG 7. The reference repository for this study is for granitic rock or gneiss as the host rock. The descriptions of waste packages and repository facilities used in this study represent only one of many possible designs based on the multiple barriers concept. The repository's size is based on a nuclear economy producing 100 gigawatts of electricity per year for 1 year. The objective of the modeling efforts presented in this study is to predict the rate of transport of radioactive contaminants from the repository through the geosphere to the biosphere and thus determine an estimate of the potential dose to humans so that the release consequence impacts of the various fuel cycles can be compared. Currently available hydrologic, leach, transport, and dose models were used in this study

Use of ornamental rock waste to fabricate rustic ceramic tile: industrial test

International Nuclear Information System (INIS)

Pacheco, A.T.; Monteiro, S.N.

2011-01-01

This work has as its objective to produce rustic wall tiles with the use of a waste from the sawing of gnaisse rock mixed with kaolinitic replacing sand. Compositions were prepared using clay, sand and waste, The wall tiles were fire in a industrial dome type furnace at 850 deg C.The physical and mechanical properties determined were water absorption and flexural rupture strength. The results indicated that the waste did not improve the evaluated properties by replacing sand. This is mainly due to the low temperature used in the experiment. (author)

Uranium ((234)U, (235)U and (238)U) contamination of the environment surrounding phosphogypsum waste heap in Wiślinka (northern Poland).

Science.gov (United States)

Olszewski, Grzegorz; Boryło, Alicja; Skwarzec, Bogdan

2015-08-01

The aim of this work was to determine the uranium concentration ((234)U, (235)U and (238)U) and values of the activity ratio (234)U/(238)U in soil samples collected near phosphogypsum waste heap in Wiślinka (northern Poland). On the basis of the studies it was found that the values of the (234)U/(238)U activity ratio in the analyzed soils collected in the vicinity of phosphogypsum dump in Wiślinka are in most cases close to one and indicate the phosphogypsum origin of the analyzed nuclides. The obtained results of uranium concentrations are however much lower than in previous years before closing of the phosphogypsum stockpile. After this process and covering the phosphogypsum stockpile in Wiślinka with sewage sludge, phosphogypsum particles are successfully immobilized. In the light of the results the use of phosphate fertilizers seems to be a major problem. Prolonged and heavy rains can cause leaching accumulated uranium isotopes in the phosphogypsum stockpile, which will be washed into the Martwa Wisła and on the fields in the immediate vicinity of this storage. Copyright © 2015 Elsevier Ltd. All rights reserved.

The copper spoil heap Knappenberg, Austria, as a model for metal habitats – Vegetation, substrate and contamination

Energy Technology Data Exchange (ETDEWEB)

Adlassnig, Wolfram; Weiss, Yasmin S. [University of Vienna, Core Facility Cell Imaging and Ultrastructure Research, Althanstraße 14, A-1090 Vienna (Austria); Sassmann, Stefan [University of Vienna, Core Facility Cell Imaging and Ultrastructure Research, Althanstraße 14, A-1090 Vienna (Austria); University of Exeter, College of Life and Environmental Sciences, Biosciences, Stocker Road, Exeter EX4 4QD (United Kingdom); Steinhauser, Georg [Leibniz University Hannover, Institute of Radioecology and Radiation Protection, Herrenhäuser Straße 2, D30419 Hannover (Germany); Hofhansl, Florian [University of Vienna, Department of Microbiology and Ecosystem Science, Althanstraße 14, A-1090 Vienna (Austria); Instituto Nacional de Pesquisas da Amazônia, Coordenação de Dinâmica Ambiental, Manaus (Brazil); Baumann, Nils [Helmholtz-Zentrum Dresden-Rossendorf, Division of Biogeochemistry, Bautzner Landstraße 400, D-01328 Dresden (Germany); Lichtscheidl, Irene K. [University of Vienna, Core Facility Cell Imaging and Ultrastructure Research, Althanstraße 14, A-1090 Vienna (Austria); Lang, Ingeborg, E-mail: ingeborg.lang@univie.ac.at [University of Vienna, Core Facility Cell Imaging and Ultrastructure Research, Althanstraße 14, A-1090 Vienna (Austria)

2016-09-01

Historic mining in the Eastern Alps has left us with a legacy of numerous spoil heaps hosting specific, metal tolerant vegetation. Such habitats are characterized by elevated concentrations of toxic elements but also by high irradiation, a poorly developed substrate or extreme pH of the soil. This study investigates the distribution of vascular plants, mosses and lichens on a copper spoil heap on the ore bearing Knappenberg formed by Prebichl Layers and Werfener Schist in Lower Austria. It serves as a model for discriminating between various ecological traits and their effects on vegetation. Five distinct clusters were distinguished: (1) The bare, metal rich Central Spoil Heap was only colonised by highly resistant specialists. (2) The Northern and (3) Southern Peripheries contained less copper; the contrasting vegetation was best explained by the different microclimate. (4) A forest over acidic bedrock hosted a vegetation overlapping with the periphery of the spoil heap. (5) A forest over calcareous bedrock was similar to the spoil heap with regard to pH and humus content but hosted a vegetation differing strongly to all other habitats. Among the multiple toxic elements at the spoil heap, only Cu seems to exert a crucial influence on the vegetation pattern. Besides metal concentrations, irradiation, humidity, humus, pH and grain size distribution are important for the establishment of a metal tolerant vegetation. The difference between the species poor Northern and the diverse Southern Periphery can be explained by the microclimate rather than by the substrate. All plant species penetrating from the forest into the periphery of the spoil heap originate from the acidic but not from the calcareous bedrock. - Highlights: • Strong impact on plant diversity by isolation and extreme abiotic conditions • Both, microclimate and substrate explain species distribution. • Increased cellular metal tolerance of plants from the Central Spoil Heap • Among toxic elements

Retrievability of high-level nuclear waste from geologic repositories - Regulatory and rock mechanics/design considerations

International Nuclear Information System (INIS)

Tanious, N.S.; Nataraja, M.S.; Daemen, J.J.K.

1987-01-01

Retrievability of nuclear waste from high-level geologic repositories is one of the performance objectives identified in 10CFR60 (Code of Federal Regulations, 1985). 10CFR60.111 states that the geologic repository operations area shall be designed to preserve the option of waste retrieval. In designing the repository operations area, rock mechanics considerations play a major role especially in evaluating the feasibility of retrieval operations. This paper discusses generic considerations affecting retrievability as they relate to repository design, construction, and operation, with emphasis on regulatory and rock mechanics aspects

Rheological characteristics of waste rock materials in abandoned mine deposit and debris flow hazards

Science.gov (United States)

Jeong, Sueng-Won; Lee, Choonoh; Cho, Yong-Chan; Wu, Ying-Hsin

2015-04-01

In Korea, approximately 5,000 metal mines are spread, but 50% of them are still abandoned without any proper remediation and cleanup. Summer heavy rainfall can result in the physicochemical modification of waste rock materials in the mountainous. From the geotechnical monitoring and field investigation, there are visible traces of mass movements every year. Soil erosion is one of severe phenomena in the study area. In particular, study area is located in the upper part of the Busan Metropolitan City and near the city's water supply. With respect to the supply of drinking water and maintenance of ecological balance, proper disposal of waste rock materials is required. For this reason, we examine the rheological properties of waste rock materials as a function of solid content using a ball- and vane-penetrated rheometer. In the flow curves, which are the relationship between the shear stress and shear rate of waste rock materials, we found that the soil samples exhibited a shear thinning beahivor regardless of solid content. The Bingham, Herschel-Bulkley, Power-law, and Papanastasiou models are used to determine the rheological properties. Assuming that the soil samples behaved as the viscoplastic behavior, the yield stress and viscosity are determined for different water contents. As a result, there are clear relationships between the solid content and rheological values (i.e., Bingham yield stress and plastic viscosity). From these relationships, the maximum and minimum of Bingham yield stresses are ranged from 100 to 2000 Pa. The debris flow mobilization is analysed using a 1D BING and 2D Debris flow models. In addition, the effect of wall slip and test apparatus are discussed.

Long-term temporal variability of the radon-222 exhalation flux from a landform covered by low uranium grade waste rock

International Nuclear Information System (INIS)

Bollhöfer, Andreas; Doering, Che

2016-01-01

Radon-222 exhalation flux densities from two different substrates of several metres thickness, waste rock and waste rock mixed with approximately 30% lateritic material, were measured over a period of five years in the wet-dry tropics of Northern Australia. Fourteen measurement campaigns using activated charcoal canisters (n > 1000) covered both dry and wet seasons and showed differences in seasonal and long term trends of the "2"2"2Rn exhalation flux densities normalised to the "2"2"6Ra activity concentrations of the substrate. Dry season "2"2"2Rn exhalation was generally higher for the mixed substrate, due to the larger fraction of fines. Seasonality established within the first year of landform construction on the mixed substrate, due to the higher water holding capacity of the lateritic material. In contrast, waste rock only shows no seasonality until years four and five after construction, when average normalised dry season "2"2"2Rn exhalation flux densities from waste rock increase to values (0.47 ± 0.06 mBq m"−"2 s"−"1 per Bq kg"−"1) similar to the mixed substrate (0.64 ± 0.08 mBq m"−"2 s"−"1 per Bq kg"−"1), likely due to an increase in fines from rapid weathering of the schistose waste rock. Volumetric water content has been used to parametrize relative "2"2"2Rn exhalation and we determined that wet season "2"2"2Rn exhalation is about 40% of the dry season exhalation. - Highlights: • We determined "2"2"2Rn exhalation flux densities normalised to "2"2"6Ra activity concentrations (R_E_-_R) for two substrates. • R_E_-_R was lower for waste rock only compared to waste rock blended with 30% fine grained lateritic material. • Seasonality in waste rock "2"2"2Rn exhalation flux densities established 4 years after construction. • Wet season R_E_-_R was about 40% of the dry season R_E_-_R.

Weathering behavior of mine tailings and waste rock: A surface investigation

International Nuclear Information System (INIS)

Domvile, S.J.; Li, M.G.; Sollner, D.D.; Nesbitt, W.

1994-01-01

A study focusing on the ion movement in the near surface of sulfide minerals was conducted to better understand the weathering mechanisms of mine waste materials. Tailings and waste rock samples from Canadian mines were subjected to controlled weathering studies using various chemical leachants. Leachates were analyzed for various parameters, and petrographic analyses were conducted on the solid residues. Laboratory oxidation studies of pure pyrrhotite and arsenopyrite were carried out using the surface techniques X-ray photoelectron spectroscopy (XPS) and auger electron spectroscopy (AES). The data derived from the weathering study and the surface techniques were correlated to determine mechanisms of oxidation. Several results were observed during the project: ferric iron constitutes one third of the iron present in pyrrhotite, sulfide oxidation is initiated when rock is blasted, sulfide sulfur is oxidized to di- and poly-sulfides prior to forming sulfates, and significantly more sulfate is produced upon exposure to aqueous environments than to air alone

Chemical modeling of irreversible reactions in nuclear waste-water-rock systems

International Nuclear Information System (INIS)

Wolery, T.J.

1981-02-01

Chemical models of aqueous geochemical systems are usually built on the concept of thermodynamic equilibrium. Though many elementary reactions in a geochemical system may be close to equilibrium, others may not be. Chemical models of aqueous fluids should take into account that many aqueous redox reactions are among the latter. The behavior of redox reactions may critically affect migration of certain radionuclides, especially the actinides. In addition, the progress of reaction in geochemical systems requires thermodynamic driving forces associated with elementary reactions not at equilibrium, which are termed irreversible reactions. Both static chemical models of fluids and dynamic models of reacting systems have been applied to a wide spectrum of problems in water-rock interactions. Potential applications in nuclear waste disposal range from problems in geochemical aspects of site evaluation to those of waste-water-rock interactions. However, much further work in the laboratory and the field will be required to develop and verify such applications of chemical modeling

Nuclear waste. DOE has terminated research evaluating crystalline rock for a repository

International Nuclear Information System (INIS)

Fultz, Keith O.; Sprague, John W.; Weigel, Dwayne E.; Price, Vincent P.

1989-05-01

We found that DOE terminated funding of research projects specifically designed to evaluate the suitability of crystalline rock for a repository. DOE continued other research efforts involving crystalline rock because they will provide information that it considers useful for evaluating the suitability of Yucca Mountain, Nevada, for a potential repository. Such research activities are not prohibited by the amendments. In January 1988, DOE began evaluating both its domestic and international research programs to ensure their compliance with the 1987 amendments. Several DOE offices and contractors were involved in the evaluation. DOE officials believe that the evaluation effectively brought the Office of Civilian Radioactive Waste Management activities into compliance with the amendments while maintaining useful international relations of continuing benefit to the nuclear waste program in general and to DOE's investigation of the Yucca Mountain site in particular. (The 1987 amendments designated Yucca Mountain as the only site that DOE is to investigate for a potential repository.) The approach and results of DOE's evaluation are discussed. Our review of DOE documents indicates that, by June 22, 1988, DOE completed its evaluation of ongoing crystalline rock research projects to ensure compliance with the 1987 amendments, terminated those research activities it identified as being specifically designed to evaluate the suitability of crystalline rock for a repository, continued some research activities involving crystalline rock because these activities would benefit the investigation and development of the Yucca Mountain repository site, and redirected some research activities so that they would contribute to investigating and developing the Yucca Mountain site

Fast heap transform-based QR-decomposition of real and complex matrices: algorithms and codes

Science.gov (United States)

Grigoryan, Artyom M.

2015-03-01

In this paper, we describe a new look on the application of Givens rotations to the QR-decomposition problem, which is similar to the method of Householder transformations. We apply the concept of the discrete heap transform, or signal-induced unitary transforms which had been introduced by Grigoryan (2006) and used in signal and image processing. Both cases of real and complex nonsingular matrices are considered and examples of performing QR-decomposition of square matrices are given. The proposed method of QR-decomposition for the complex matrix is novel and differs from the known method of complex Givens rotation and is based on analytical equations for the heap transforms. Many examples illustrated the proposed heap transform method of QR-decomposition are given, algorithms are described in detail, and MATLAB-based codes are included.

Effects of Pregnant Leach Solution Temperature on the Permeability of Gravelly Drainage Layer of Heap Leaching Structures

Directory of Open Access Journals (Sweden)

mehdi amini

2013-12-01

Full Text Available In copper heap leaching structures, the ore is leached by an acidic solution. After dissolving the ore mineral, the heap is drained off in the acidic solution using a drainage system (consisting of a network of perforated polyethylene pipes and gravelly drainage layers and is, then, transferred to the leaching plant for copper extraction where the copper is extracted and the remaining solution is dripped over the ore heap for re-leaching. In this process, the reaction between the acidic solution and copper oxide ore is exothermal and the pregnant leach solution (PLS, which is drained off the leaching heap, has a higher temperature than the dripped acidic solution. The PLS temperature variations cause some changes in the viscosity and density which affect the gravelly drainage layer's permeability. In this research, a special permeability measuring system was devised for determining the effects of the PLS temperature variations on the permeability coefficient of the gravelly drainage layer of heap leaching structures. The system, consisting of a thermal acid resistant element and a thermocouple, controls the PLS temperature, which helps measure the permeability coefficient of the gravelly drainage layer. The PLS and gravelly drainage layer of Sarcheshmeh copper mine heap leaching structure No. 1 were used in this study. The permeability coefficient of the gravelly soil was measured against the PLS and pure water at temperatures varying between 3°C to 60°C. Also, the viscosity and density of the PLS and pure water were measured at these temperatures and, using existing theoretical relations, the permeability coefficient of the gravel was computed. A comparison between the experimental and theoretical results revealed a good conformity between the two sets of results. Finally, a case (Taft heap leaching structure, Yazd, Iran was studied and its gravelly drainage layer was designed based on the results of the present research.

Investigation on the oxygen transport mechanisms in the Sarcheshmeh waste rock dumps

Directory of Open Access Journals (Sweden)

Saeed Yousefi

2015-04-01

Full Text Available Introduction Pyrite oxidation and acid mine drainage (AMD are the serious environmental problems associated with the mining activities in sulphide ores. The rate of pyrite oxidation is governed by the availability of oxygen (Borden, 2003. Therefore, the identifying oxygen supplying mechanism is one of the most important issues related to the environmental assessment of waste rock dumps (Cathles and Apps, 1975; Jaynes et al., 1984; Davis and Ritchie, 1986. Although comprehensive researches were performed on the mathematical description of oxygen transport processes using the numerical modeling (Morin et al., 1988; Blowes et al., 1991; Wunderly et al., 1986; Elberling et al., 1994; Jannesar Malakooti et al., 2014, so far, the interactions between these processes and geochemical and mineralogical characteristics has not been studied especially in waste rock dumps. Therefore the main objective of this study is to identify the evidences for knowing the oxygen transport mechanisms in the waste dumps and also, its role in intensity of pyrite oxidation. It is expected that such these structural studies could be useful for better understanding of dominant processes in numerical modeling and also providing environmental management strategies in the study area and other sites by similar characteristics. Materials and Methods In this study, thirty solid samples were collected from six excavated trenches in the waste rock dumps No. 19 and 31 of the Sarcheshmeh porphyry copper mine. Collected samples were studied using several methods such as XRD, ASTM-D2492, paste pH and grain size distribution. The results obtained from these methods were used with the field observations in order to characterize some detail information about oxygen supplying mechanisms for oxidation reactions in the waste rock dumps. Result The main minerals found by the XRD analysis were quartz and muscovite which were present in all samples. Pyrite, orthose, albite, and chlorite were also

Coarsening of Faraday Heaps: Experiment, Simulation, and Theory

NARCIS (Netherlands)

Gerner, van H.J.; Robledo, Caballero G.A.; Meer, van der D.; Weele, van der J.P.; Hoef, van der M.A.

2009-01-01

When a layer of granular material is vertically shaken, the surface spontaneously breaks up in a landscape of small Faraday heaps that merge into larger ones on an ever increasing time scale. This coarsening process is studied in a linear setup, for which the average life span of the transient state

Pirm wastes: permanent isolation in rock-forming minerals

International Nuclear Information System (INIS)

Smyth, J.R.; Vidale, R.J.; Charles, R.W.

1977-01-01

The most practical system for permanent isolation of radioactive wastes in granitic and pelitic environments may be one which specifically tailors the waste form to the environment. This is true because if recrystallization of the waste form takes place within the half-lives of the hazardous radionuclides, it is likely to be the rate-controlling step for release of these nuclides to the ground-water system. The object of the proposed waste-form research at Los Alamos Scintific Laboratory (LASL) is to define a phase assemblage which will minimize chemical reaction with natural fluids in a granitic or pelitic environment. All natural granites contain trace amounts of all fission product elements (except Tc) and many contain minor amounts of these elements as major components of certain accessory phases. Observation of the geochemistry of fission-product elements has led to the identification of the natural minerals as target phases for research. A proposal is made to experimentally determine the amounts of fission product elements which can stably be incorporated into the phases listed below and to determine the leachability of the assemblage this produced using fluids typical of the proposed environments at the Nevada Test Site. This approach to waste isolation satisfies the following requirements: (1) It minimizes chemical reaction with the environment (i.e., recrystallization) which is likely to be the rate-controlling step for release of radionuclides to groundwater; (2) Waste loading (hence temperature) can be easily varied by dilution with material mined from the disposal site; (3) No physical container is required; (4) No maintenance is required (permanent); (5) The environment acts as a containment buffer. It is proposed that such wastes be termed PIRM wastes, for Permanent Isolation in Rock-forming Minerals

Review of important rock mechanics studies required for underground high level nuclear waste repository program

Energy Technology Data Exchange (ETDEWEB)

Kwon, S.; Cho, W. J

2007-01-15

Disposal concept adapting room and pillar method, which is a confirmed technique in mining and tunnel construction for long time, has advantages at cost, safety, technical feasibility, flexibility, and international cooperation point of views. Then the important rock mechanics principals and in situ and laboratory tests for understanding the behavior of rock, buffer, and backfill as well as their interactions will be reviewed. The accurate understanding of them is important for developing a safe disposal concept and successful operation of underground repository for permanent disposal of radioactive wastes. First of all, In this study, current status of rock mechanics studies for HLW disposal in foreign countries such as Sweden, USA, Canada, Finland, Japan, and France were reviewed. After then the in situ and laboratory tests for site characterization were summarized. Furthermore, rock mechanics studies required during the whole procedure for the disposal project from repository design to the final closure will be reviewed systematically. This study will help for developing a disposal system including site selection, repository design, operation, maintenance, and closure of a repository in deep underground rock. By introducing the required rock mechanics tests at different stages, it would be helpful from the planning stage to the operation stage of a radioactive waste disposal project.

Review of important rock mechanics studies required for underground high level nuclear waste repository program

International Nuclear Information System (INIS)

Kwon, S.; Cho, W. J.

2007-01-01

Disposal concept adapting room and pillar method, which is a confirmed technique in mining and tunnel construction for long time, has advantages at cost, safety, technical feasibility, flexibility, and international cooperation point of views. Then the important rock mechanics principals and in situ and laboratory tests for understanding the behavior of rock, buffer, and backfill as well as their interactions will be reviewed. The accurate understanding of them is important for developing a safe disposal concept and successful operation of underground repository for permanent disposal of radioactive wastes. First of all, In this study, current status of rock mechanics studies for HLW disposal in foreign countries such as Sweden, USA, Canada, Finland, Japan, and France were reviewed. After then the in situ and laboratory tests for site characterization were summarized. Furthermore, rock mechanics studies required during the whole procedure for the disposal project from repository design to the final closure will be reviewed systematically. This study will help for developing a disposal system including site selection, repository design, operation, maintenance, and closure of a repository in deep underground rock. By introducing the required rock mechanics tests at different stages, it would be helpful from the planning stage to the operation stage of a radioactive waste disposal project

Modeling of thermal evolution of near field area around single pit mode nuclear waste canister disposal in soft rocks

International Nuclear Information System (INIS)

Bajpai, R.K.; Verma, A.K.; Maheshwar, Sachin

2016-01-01

Soft rocks like argillites/shales are under consideration worldwide as host rock for geological disposal of vitrified as well as spent fuel nuclear waste. The near field around disposed waste canister at 400-500m depth witnesses a complex heat field evolution due to varying thermal characteristics of rocks, coupling with hydraulic processes and varying intensity of heat flux from the canister. Smooth heat dissipation across the rock is desirable to avoid buildup of temperature beyond design limit (100 °C) and resultant micro fracturing due to thermal stresses in the rocks and intervening buffer clay layers. This also causes enhancement of hydraulic conductivity of the rocks, radionuclide transport and greater groundwater ingress towards the canister. Hence heat evolution modeling constitutes an important part of safety assessment of geological disposal facilities

Waste disposal in granitic rocks: analysis of thermal microcracks

International Nuclear Information System (INIS)

Montoto, M.; Roeshoff, K.; Leojon, B.; Bel-Lan, A.

1981-04-01

The possible development of microcracks from a thermal origin has been researched in the granitic rocks of Shipa (Sweden), within which in a real scale have been originated some thermal gradients similar to the ones which could take place in the waste disposal. To achieve an optimal fratographic information, with some petrographic meaning, different microscopic techniques, optical and electronic, have been combined and an automatized quantification methodology has also been developed by means of digitals. Between warmed and unwarmed granitis no microfractographic differences have been detected. The observed variations are only apparent and may be explained as a function of the inherent petrographic heterogeneity of rocky blocks. In any case in the internal temperatures generated within these rocks have not attained its own threshold of thermal microcracking. (author)

77 FR 22609 - Notice of Intent To Prepare an Environmental Impact Statement for the Proposed Pan Mine Project...

Science.gov (United States)

2012-04-16

... business hours. SUPPLEMENTARY INFORMATION: Midway Gold US Inc. (Midway) proposes to construct and operate an open-pit gold mining operation, which would include open pits, a heap leach pad, waste rock dumps, and ancillary facilities. The mine would be located in the northern part of the Pancake Mountain Range...

Autogenous Tumbling Media Assessment to Clean Weathered Surfaces of Waste-Rock Particles from a Basalt Quarry

Directory of Open Access Journals (Sweden)

Baran Tufan

2015-06-01

Full Text Available In this study, the optimum feed composition in autogenous tumbling of basalt waste-rock particles to clean their weathered surface was determined. The weathered surfaces of basalt are generally cut out consequent to extraction of basalt columns in quarry operations. The inefficiently cut out portions of basalt cause formation of huge quarry waste dumps causing visual pollution on roadsides. Mixtures of different particle size fractions of basalt waste-rock particles were experimented to achieve the optimum feed material composition. The minimum loss of commercially available basalt particles and maximum clear surface was intended. The results were compared with respect to weight loss (% and reflectance values of used and generated samples.

Microorganisms in potential host rocks for geological disposal of nuclear waste and their interactions with radionuclides

Energy Technology Data Exchange (ETDEWEB)

Cherkouk, A.; Liebe, M.; Luetke, L.; Moll, H.; Stumpf, T. [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Inst. of Resource Ecology

2015-07-01

The long-term safety of nuclear waste in a deep geological repository is an important issue in our society. Microorganisms indigenous to potential host rocks are able to influence the oxidation state, speciation and therefore the mobility of radionuclides as well as gas generation or canister corrosion. Therefore, for the safety assessment of such a repository it is necessary to know which microorganisms are present in the potential host rocks (e.g. clay, salt) and if these microorganisms can influence the performance of a repository. Microbial diversity in potential host rocks for geological disposal of nuclear waste was analyzed by culture-independent molecular biological methods (e.g. 16S rRNA gene retrieval) as well as enrichment and isolation of indigenous microbes. Among other isolates, a Paenibacillus strain, as a representative of Firmicutes, was recovered in R2A media under anaerobic conditions from Opalinus clay from the Mont Terri in Switzerland. Accumulation experiments and potentiometric titrations showed a strong interaction of Paenibacillus sp. cells with U(VI) within a broad pH range (3-7). Additionally, the interactions of the halophilic archaeal strain Halobacterium noricense DSM 15987, a salt rock representative reference strain, with U(VI) at high ionic strength was investigated. After 48 h the cells were still alive at uranium concentrations up to 60 μM, which demonstrates that Halobacterium noricense can tolerate uranium concentrations up to this level. The formed uranium sorption species were examined with time-resolved laser-induced fluorescence spectroscopy (TRLFS). The results about the microbial communities present in potential host rocks for nuclear waste repositories and their interactions with radionuclides contribute to the safety assessment of a prospective nuclear waste repository.

Microorganisms in potential host rocks for geological disposal of nuclear waste and their interactions with radionuclides

International Nuclear Information System (INIS)

Cherkouk, A.; Liebe, M.; Luetke, L.; Moll, H.; Stumpf, T.

2015-01-01

The long-term safety of nuclear waste in a deep geological repository is an important issue in our society. Microorganisms indigenous to potential host rocks are able to influence the oxidation state, speciation and therefore the mobility of radionuclides as well as gas generation or canister corrosion. Therefore, for the safety assessment of such a repository it is necessary to know which microorganisms are present in the potential host rocks (e.g. clay, salt) and if these microorganisms can influence the performance of a repository. Microbial diversity in potential host rocks for geological disposal of nuclear waste was analyzed by culture-independent molecular biological methods (e.g. 16S rRNA gene retrieval) as well as enrichment and isolation of indigenous microbes. Among other isolates, a Paenibacillus strain, as a representative of Firmicutes, was recovered in R2A media under anaerobic conditions from Opalinus clay from the Mont Terri in Switzerland. Accumulation experiments and potentiometric titrations showed a strong interaction of Paenibacillus sp. cells with U(VI) within a broad pH range (3-7). Additionally, the interactions of the halophilic archaeal strain Halobacterium noricense DSM 15987, a salt rock representative reference strain, with U(VI) at high ionic strength was investigated. After 48 h the cells were still alive at uranium concentrations up to 60 μM, which demonstrates that Halobacterium noricense can tolerate uranium concentrations up to this level. The formed uranium sorption species were examined with time-resolved laser-induced fluorescence spectroscopy (TRLFS). The results about the microbial communities present in potential host rocks for nuclear waste repositories and their interactions with radionuclides contribute to the safety assessment of a prospective nuclear waste repository.

The far field heating effects of a radioactive waste depository in hard rock

International Nuclear Information System (INIS)

Hodgkinson, D.P.; Bourke, P.J.

1978-01-01

Fission product heating of the rock surrounding a depository for high level radioactive waste, will result in high temperatures and high thermal gradients over distances of several hundred metres for many centuries. The consequent thermal expansion of the rock leads to stresses which could alter the fracture pattern and therefore the permeability of the rock. These problems are assessed by considering an idealised model of a depository for which analytic solutions to the temperature and stress fields are derived. A related problem is that any water present in the fissures will tend to rise because of its decrease in density on heating. If the water had previously leached away some of the radionuclides in the waste, then this convective transport constitutes a possible leakage path back to the biosphere. For the low permeabilities expected at a depository site, it is possible to linearise the resulting equations and derive analytic solutions for the flow velocities. This procedure has been carried out for the idealised depository model, in order to estimate the magnitude of these effects

The design on high slope stabilization in waste rock sites of uranium mines

International Nuclear Information System (INIS)

Liu Taoan; Zhou Xinghuo; Liu Jia

2005-01-01

Design methods, reinforcement measures, and flood control measures concerning high slope stabilization in harnessing waste rock site are described in brief according to some examples of two uranium mines in Hunan province. (authors)

Geological disposal of high-level radioactive waste. Conceptual repository design in hard rock

International Nuclear Information System (INIS)

Beale, H.; Griffin, J.R.; Davies, J.W.; Burton, W.R.

1980-01-01

The paper gives an interim report on UK studies on possible designs for a repository for vitrified high-level radioactive waste in crystalline rock. The properties of the waste are described and general technical considerations of consequences of disposal in the rock. As an illustration, two basic designs are described associated with pre-cooling in an intermediate store. Firstly, a 'wet repository' is outlined wherein canisters are sealed up closely in boreholes in the rock in regions of low groundwater movement. Secondly, a 'dry repository' above sea level is described where emplacement in tunnels is followed by a loose backfill containing activity absorbers. A connection to deep permeable strata maintains water levels below emplacement positions. Variants on the two basic schemes (tunnel emplacement in a wet repository and in situ cooling) are also assessed. It is concluded that all designs discussed produce a size of repository feasible for construction in the UK. Further, (1) a working figure of 100 0 C per maximum rock temperature is not exceeded, (2) no insuperable engineering problems have so far been found, though rock mechanics studies are at an early stage; (3) it is not possible to discount the escape of a few long-lived 'man-made' isotopes. A minute increment to natural activity in the biosphere may occur from traces of uranium and its decay chains; (4) at this stage, all the designs are still possible candidates for the construction of a UK repository. (author)

Heap: a highly sensitive and accurate SNP detection tool for low-coverage high-throughput sequencing data

KAUST Repository

Kobayashi, Masaaki

2017-04-20

Recent availability of large-scale genomic resources enables us to conduct so called genome-wide association studies (GWAS) and genomic prediction (GP) studies, particularly with next-generation sequencing (NGS) data. The effectiveness of GWAS and GP depends on not only their mathematical models, but the quality and quantity of variants employed in the analysis. In NGS single nucleotide polymorphism (SNP) calling, conventional tools ideally require more reads for higher SNP sensitivity and accuracy. In this study, we aimed to develop a tool, Heap, that enables robustly sensitive and accurate calling of SNPs, particularly with a low coverage NGS data, which must be aligned to the reference genome sequences in advance. To reduce false positive SNPs, Heap determines genotypes and calls SNPs at each site except for sites at the both ends of reads or containing a minor allele supported by only one read. Performance comparison with existing tools showed that Heap achieved the highest F-scores with low coverage (7X) restriction-site associated DNA sequencing reads of sorghum and rice individuals. This will facilitate cost-effective GWAS and GP studies in this NGS era. Code and documentation of Heap are freely available from https://github.com/meiji-bioinf/heap (29 March 2017, date last accessed) and our web site (http://bioinf.mind.meiji.ac.jp/lab/en/tools.html (29 March 2017, date last accessed)).

A Coupled Model for Solution Flow and Bioleaching Reaction Based on the Evolution of Heap Pore Structure

Directory of Open Access Journals (Sweden)

Shenghua Yin

2014-01-01

Full Text Available Based on the basic seepage law, equations have been derived to descript the solution flow within the copper ore heap which is treated as anisotropy porous media. The relationship between heap permeability and pore ratio has been revealed. Given the consideration of cover pressure and particle dissolution, pore evolution model has been set up. The pore evolution mechanism, due to the process of dissolution, precipitation, blockage, collapse, and caking, has been investigated. The comprehensive model for pore evolution and solution flow under the effect of solute transport and leaching reaction has been established. A trapezoidal heap was calculated, and the estimated results show that permeability decreases with the decreasing of pore ratio. Therefore, the permeability of the heap with small particles is relatively low because of its low pore ratio. Furthermore, permeability and height are found to be the two main factors influencing the solution flow.

Far-field thermomechanical response of argillaceous rock to emplacement of a nuclear-waste repository

International Nuclear Information System (INIS)

McVey, D.F.; Thomas, R.K.; Lappin, A.R.

1980-08-01

Before heat-producing wastes can be emplaced safely in any argillaceous rock, it will be necessary to understand the far-field thermal and thermomechanical response of this rock to waste emplacement. This report presents the results of a first series of calculations aimed at estimating the far-field response of argillite to waste emplacement. Because the thermal and mechanical properties of argillite are affected by its content of expandable clay, its behavior is briefly compared and contrasted with that of a shale having the same matrix thermal properties, but containing no expandable clay. Under this assumption, modeled temperatures are the same for the two rock types at equivalent power densities and reflect the large dependence of in-situ temperatures on both initial power density and waste type. Thermomechanical calculations indicate that inclusion of contraction behavior of expandable clays in the assumed argillite thermal expansion behavior results, in some cases, in generation of a large zone in and near the repository that has undergone volumetric contraction but is surrounded by uniformly compressive stresses. Information available to date indicates that this contraction would likely result in locally increased fluid permeability and decreased in-situ thermal conductivity, but might well be advantageous as regards radionuclide retention, because of the increased surface area within the contracted zone. Assumption of continuous and positive expansion behavior for the shale eliminates the near-repository contraction and tensional zones, but results in near-surface tensional zones directly above the repository

A Phase-Adaptive Garbage Collector Using Dynamic Heap Partitioning and Opportunistic Collection

Science.gov (United States)

Roh, Yangwoo; Kim, Jaesub; Park, Kyu Ho

Applications usually have their own phases in heap memory usage. The traditional garbage collector fails to match various application phases because the same heuristic on the object behavior is used throughout the entire execution. This paper introduces a phase-adaptive garbage collector which reorganizes the heap layout and adjusts the invocation time of the garbage collection according to the phases. The proposed collector identifies phases by detecting the application methods strongly related to the phase boundaries. The experimental results show that the proposed phase-adaptive collector successfully recognizes application phases and improves the garbage collection time by as much as 41%.

Disposal of low- and intermediate-level solid radioactive wastes in rock cavities

International Nuclear Information System (INIS)

1983-01-01

This Guidebook summarizes the factors to be considered and the activities to be undertaken in the overall planning and development of a disposal system for solid or solidified low- and intermediate-level wastes in rock cavities. Aspects related to repository site selection, design, construction, operation, shutdown, surveillance, regulation and safety assessment are discussed here in general terms. They will be covered in greater technical detail in a separate document. This report considers the emplacement of wastes in categories II, III, IV and V, as defined in Table 3.1, in different kinds of cavities located at various depths from just below the surface to deep continental rock. The choice of the type of cavity and its depth and of the disposal site itself is related to the radiological protection requirements for the wastes concerned. The repositories considered include natural caves and abandoned mines as well as specially excavated cavities in various geological formations. Consideration is also given to hydrogeological, environmental and societal factors. The guidelines given in the report are made sufficiently general to cover a broad variety of different circumstances. Consequently, the practical application of these guidelines needs a case-by-case consideration which takes into account the local conditions, e.g. natural circumstances, the characteristics of the wastes and national and international regulations and practices

A numerical study on the structural behavior of underground rock caverns for radioactive waste disposal

International Nuclear Information System (INIS)

Kim, Sun Hoon; Choi, Kyu Sup; Lee, Kyung Jin; Kim, Dae Hong

1991-01-01

In order to design safe and economical underground disposal structures for radioactive wastes, understanding the behavior of discontinuous rock masses is essential. This study includes discussions about the computational model for discontinuous rock masses and the structural analysis method for underground storage structures. Then, based on an engineering judgement a suitable selection and slight modifications on computational models and analysis methods have been made in order to analyze and understand the structural behavior of the rock cavern with discontinuities

Microstructural variation of vitrified floor tile incorporated with granitic rock waste; Variacao microestrutural de piso ceramico vitrificado incorporado com residuos de rocha granitica

Energy Technology Data Exchange (ETDEWEB)

Souza, A.J.; Holanda, J.N.F., E-mail: ajsouza@uenf.b [Universidade Estadual do Norte Fluminense Darcy Ribeiro (LAMAV/CCT/UENF), Campos dos Goytacazes, RJ (Brazil). Lab. de Materiais Avancados. Grupo de Materiais Ceramicos

2009-07-01

The ornamental rock industry from Northwest Fluminense generates huge amounts of wastes in the form of a fine powder. These wastes are deposited in nature without any care about environmental degradation, which can cause damage to public health, pollution of the natural water sources, and silted banks of rivers. In addition, they also can to affect the landscape aesthetically. In this work was used a granitic rock waste from Santo Antonio de Padua-RJ. This waste is rich in alkaline oxides, which promote the formation of liquid phase and assist the densification of traditional ceramics. The ceramic bodies with up to 47.5% granitic rock waste were pressed at 50 MPa. The ceramic pieces were fired at 1250 deg C. The evolution of sintered microstructure was evaluated by scanning electron microscopy and X-ray diffraction. The results showed that the granitic rock waste influences significantly the microstructure of the sintered ceramic bodies. (author)

Role of rock texture and mineralogy on the hydrology and geochemistry of three neutral-drainage mesoscale experimental waste rock piles at the Antamina Mine, Peru

Science.gov (United States)

Peterson, H.; Bay, D. S.; Beckie, R. D.; Mayer, K. U.; Klein, B.; Smith, L.

2009-12-01

An ongoing study at the Antamina Cu-Zn-Mo mine in Peru investigates the hydrology and geochemistry of heterogeneous waste rock at multiple scales. Three of five instrumented mesoscale experimental waste rock piles (36m X 36m X 10m high) were constructed between 2006 and 2008. The coarsest-grained Pile 1 exhibits rapid, intense response to rain and returns to residual saturation relatively quickly, suggesting a significant influence of preferential flow in addition to high-conductivity matrix flow. Pile 2, the finest-grained of the three piles, exhibits signals from rain events that are significantly delayed and muted in comparison to those from Pile 1. Except for in the finest size fractions, the particle size distribution of Pile 3 closely resembles that of Pile 2, yet Pile 3 responds to rain events more similarly to Pile 1 than Pile 2. The presence of large boulders in Pile 3 could facilitate preferential flow, either through surface flow effects across boulders or by contributing to the formation of unfilled void space acting as macropores at high infiltration rates. The rapid rain event response of Pile 3 could also be attributed to a silt-clay percentage that is similar to Pile 1, which is less than half of the silt-clay percentage observed in Pile 2 (i.e., ~3%, ~8.5%, and ~4% for Piles 1, 2 and 3, respectively). For each of the three piles, the pH of effluent collected from bottom lysimeters and internal pore water sampled with suction lysimeters has remained circumneutral, with notable maximum concentrations of 2.8 mg/L Zn from Pile 1, which is comprised of slightly reactive hornfels and marble waste rock; 13.4 mg/L Zn and 22.7 mg/L Mo from Pile 2, comprised of reactive intrusive waste rock; and 42.5 mg/L Zn from Pile 3, comprised of reactive exoskarn waste rock. Ongoing work includes analysis of two additional mixed-rock experimental piles, studies to investigate the role of microbes on metal release (Dockrey et al., this session), analysis of pore gas

Uptake of Radium by Grass and Shrubs Grown on Mineral Heaps: A Preliminary Study

International Nuclear Information System (INIS)

Laili, Z.; Omar, M.; Yusof, M.A. Wahab; Ibrahim, M.Z.

2015-01-01

A preliminary study of the uptake of 226 Ra and 228 Ra by grass and shrubs grown on mineral heaps was carried out. Activity concentrations of 226 Ra and 228 Ra in grass and shrubs were measured using gamma spectrometry. The result showed that grass and shrubs grown on mineral heaps contained elevated levels of radium compared to grass and shrubs grown on normal soils. Thus, these plants might be used for phytoremediation of radium contaminated soil. (author)

Hydrology of an abandoned uranium mine waste rock dump, Northern Territory

International Nuclear Information System (INIS)

Evans, K.G.; Moliere, D.R.; Saynor, M.J.

1999-01-01

Field studies were conducted on an abandoned, degraded uranium mine in Kakadu National Park to obtain waste rock dump runoff data to test the ability of a landform evolution model to predict gullying caused by concentrated flow. Runoff data were collected from natural rainfall events on a concentrated flow site and an overland flow erosion site on the waste rock dump at Scinto 6 mine. The data were used to fit parameters to a rainfall/runoff model using a non-linear regression package (NLFIT-DISTFW) which allows a single set of parameters to be fitted to four discharge hydrographs simultaneously. The model generally predicted peak discharge and the rising stage of the observed hydrographs well but there was some lag in the falling stage of the predicted hydrographs. Kinematic wave parameters are dependent on each other and the concentrated flow parameter set was not significantly different from the overland flow set. The infiltration parameter sets were statistically different and difference in cumulative infiltration between sites is controlled by sorptivity

Review of potential host rocks for radioactive waste disposal in the Piedmont Province of Georgia

International Nuclear Information System (INIS)

Wenner, D.B.; Gillon, K.A.

1980-10-01

A literature study was conducted on the Piedmont province of Georgia to designate areas that may be favorable for field exploration for consideration of a repository for storage of radioactive waste. The criteria utilized in such a designation was based upon consideration of the rock unit having favorable geological, geotechnical, and geohydrological features. The most important are that the rock unit have: (1) satisfactory unit dimensions (> 100 km 2 outcrop area and at least 1500 meters (approx. 5000 feet) depth of a continuous rock type); and (2) acceptable geohydrological conditions. Among all rock types, it is concluded that the granites of the large post-metamorphic plutons and large, homogeneous orthogneissic units offer the most favorable geologic settings for exploration for siting a radioactive waste repository. Virtually all other rock types, including most metavolcanic and metasedimentary lithologies have unacceptable unit dimensions, generally unfavorable geohydrologic settings, and deleterious mechanical and physical geotechnical properties. After consideration of all major lithologies that comprise the Georgia Piedmont, the following units were deemed favorable: (1) the Elberton Pluton; (2) the Siloam Pluton; (3) the Sparta Pluton; (4) two unnamed plutons adjacent to the Snelson body of S.W. Georgia; (5) the Lithonia Gneiss; (6) basement orthogneisses and charnockites of the Pine Mountain Belt

Effects of bacterial action on waste rock producing acid drainage in the Brazilian first uranium mine

International Nuclear Information System (INIS)

Rey-Silva, Daniela V.F.M.; Oliveira, Alexandre P. de; Geraldo, Bianca; Campos, Michele B.; Azevedo, Heliana de; Barreto, Rodrigo P.; Souza-Santos, Marcio L. de

2009-01-01

This work is an evolution of the methodology showed in the paper 'Study of waste of waste rock piles producing acid drainage in the Brazilian first uranium mine', also submitted for INAC2009. Therefore, the present work also related to the determination of chemical species leaching from waste rock pile 4 (WRP4) of the Uranium Mine and Milling Facility located in the Pocos de Caldas Plateau, as well as the generation of acid waters. With the previous experimental setup, it has been observed that not only water and available oxygen are significant to pyrite oxidation reaction, but bacterial activity as well. As a first approach, the present work addresses the same experiment, but now testing without the influence of bacterial action. Therefore, the new methodology and experimental setup is now capable of determining the acidity of water in contact with material from the WRP4 and the concentration of chemical species dissolved as function of time. Such would also show the extent of bacterial action interference on the pyrite oxidation reaction. Results are based on mass balances comparing concentrations of chemical species in the waste rock before the experiment and in the waste rock plus the remaining water after the experiment. In addition, the evolution of the pH and EMF (electromotive force) values along with chemical species quantified through the experiment are presented through graphics. That is followed by discussions on the significance of such results in terms of concentration of the involved chemical species. The present work has also shown the need of improving the injection of air into the system. A more sophisticated experimental setup should be assembled in the near future, which would allow the quantification of differences between experimental tests with and without bacterial action. (author)

The current state of the heaps in Rosicko-Oslavany coal-field and the possibilities of their utilization; Soucasny stav hald v Rosicko-oslavanskem uhelnem reviru a moznosti jejich vyuziti

Energy Technology Data Exchange (ETDEWEB)

Svoboda, M. [Univerzita Palackeho v Olomouci, Prirodovedecka fakulta, Katedra rozvojovych studii, 77146 Olomouc (Czech Republic)

2013-04-16

The purpose of the article is to assess the importance of heaps for the land Rosicko-Oslavany coal-field. The heap is an anthropogenic land-form resulting from the accumulation of mineral resources extracted from the land. The heap shows as an unusual geomorfophological shape, which does not belong to the environment at first glance. In many respects the heap acts as a barrier for the other development because the heap may contains a dangerous material or may be unstable because of wrong storage of the material. The heaps in studied region stem from the black coal mining. The totals of 11 heaps were discovered during the field reconnaissance. While the heap Jindrich has a good potential for the other use, the heap Kukla represents a burden for its nearest surroundings. (authors)

Environmental impacts of waste produced from processing of different uraniferous rock samples

Directory of Open Access Journals (Sweden)

Ibrahim E. El Aassy

2016-07-01

Full Text Available Radon exhalation rates from five studied laboratory waste samples resulted from five different sedimentary rock types named sandy dolostone, siltstone –two samples-, marly claystone and black shale were measured using ‘‘Sealed Can technique”. These rates were found to vary between 0.005 and 0.015 Bq m−2 h−1. A positive correlation was found between the radon exhalation rates and the radium activities. The emanation coefficients were calculated for these laboratory waste samples which varied between 0.0004 and 0.0007 according to the physical and chemical characterize of the wastes. These results are partially in accordance with autonite acid leached tailings on laboratory scale (USA. These results led us to pay attention about the effect and impact of these wastes on the environment.

Acidic Microenvironments in Waste Rock Characterized by Neutral Drainage: Bacteria–Mineral Interactions at Sulfide Surfaces

Directory of Open Access Journals (Sweden)

John W. Dockrey

2014-03-01

Full Text Available Microbial populations and microbe-mineral interactions were examined in waste rock characterized by neutral rock drainage (NRD. Samples of three primary sulfide-bearing waste rock types (i.e., marble-hornfels, intrusive, exoskarn were collected from field-scale experiments at the Antamina Cu–Zn–Mo mine, Peru. Microbial communities within all samples were dominated by neutrophilic thiosulfate oxidizing bacteria. However, acidophilic iron and sulfur oxidizers were present within intrusive waste rock characterized by bulk circumneutral pH drainage. The extensive development of microbially colonized porous Fe(III (oxyhydroxide and Fe(III (oxyhydroxysulfate precipitates was observed at sulfide-mineral surfaces during examination by field emission-scanning electron microscopy-energy dispersive X-ray spectroscopy (FE-SEM-EDS. Linear combination fitting of bulk extended X-ray absorption fine structure (EXAFS spectra for these precipitates indicated they were composed of schwertmannite [Fe8O8(OH6–4.5(SO41–1.75], lepidocrocite [γ-FeO(OH] and K-jarosite [KFe3(OH6(SO42]. The presence of schwertmannite and K-jarosite is indicative of the development of localized acidic microenvironments at sulfide-mineral surfaces. Extensive bacterial colonization of this porous layer and pitting of underlying sulfide-mineral surfaces suggests that acidic microenvironments can play an important role in sulfide-mineral oxidation under bulk circumneutral pH conditions. These findings have important implications for water quality management in NRD settings.

Close-out of open pit and waste rock piles of a uranium mine in Guangxi province of China

International Nuclear Information System (INIS)

Xu Lechang; Zhang Zhao; Zhang Guopu; Liu Min

2012-01-01

Close-out of projects of a mine in Guangxi province of China includes open pit,east and west waste rock piles, ore transfer station, industrial fields, buildings, ore transporting road, and equipment and conduits. The following remediation limits are introduced: environment penetrating radiation dose rate and 222 Rn flux of open pit and waste rock piles, 226 Ra specific activity of soil and individual dose. Remediation objective and programme are discussed in details. Remediation effects are evaluated. (authors)

A Study of the Solid Waste Chain in Benin Metropolis, Nigeria ...

African Journals Online (AJOL)

Benin metropolis like other fast urbanizing towns and cities in Nigeria is faces with a solid waste management problem. Solid waste is seen in huge heaps on any piece of unused land, around buildings, in the open market places and in drainage and water ways. The work reported in this paper involves a study of the path ...

A study of radon emanation from waste rock at Northern Territory uranium mines

International Nuclear Information System (INIS)

Mason, G.C.; Gan, T.H.; Elliott, G.

1983-01-01

Field measurements were made of radon emanation rates from waste rock sources at Ranger, Nabarlek and Rum Jungle, three Northern Territory uranium mine sites. The preliminary mean emanation rate was approximately 50 Bq m - 2 s - 2 per percent ore grade

Reclamation of waste rock material at the Summitville Mine Superfund site using organic matter and topsoil treatments

Energy Technology Data Exchange (ETDEWEB)

Winter, M.E.; Redente, E.F.

1999-07-01

The Summitville Mine was a high elevation (3,500 m) open-pit gold mine located in southwestern Colorado. The mine was abandoned in 1992 leaving approximately 200 ha of disturbed area comprised partially of two large waste rock piles. Reclamation of waste rock material is challenging due to extreme climatic conditions in conjunction with a high acid-production potential and low organic matter concentration of the material. In addition, stockpiled topsoil at the site is acidic and may be biologically inactive due to long-term storage, and therefore sufficient plant growth medium may be limited. The purpose of this study was to determine the effect of organic amendments (mushroom compost vs. biosolids) and topsoil (stockpiled vs. nonstockpiled) on aboveground biomass, herbaceous cover, and trace element uptake. An on-site field study was established in 1995 to identify the most effective combination of treatments for successful reclamation of waste rock material. Incorporation of organic matter increased total aboveground production and cover, with mushroom compost being more effective than biosolids, but did not show significant trends relative to trace element uptake. The use of topsoil did not show a significant response relative to aboveground production, cover, and trace element uptake. This study shows that waste rock materials can be directly revegetated if properly neutralized, fertilized, and amended with organic matter. Additionally, stockpiled topsoil was equivalent in plant growth to non-stockpiled topsoil when neutralized with lime.

STAFAN, Fluid Flow, Mechanical Stress in Fractured Rock of Nuclear Waste Repository

International Nuclear Information System (INIS)

Huyakorn, P.; Golis, M.J.

1989-01-01

1 - Description of program or function: STAFAN (Stress And Flow Analysis) is a two-dimensional, finite-element code designed to model fluid flow and the interaction of fluid pressure and mechanical stresses in a fractured rock surrounding a nuclear waste repository. STAFAN considers flow behavior of a deformable fractured system with fracture-porous matrix interactions, the coupling effects of fluid pressure and mechanical stresses in a medium containing discrete joints, and the inelastic response of the individual joints of the rock mass subject to the combined fluid pressure and mechanical loading. 2 - Restrictions on the complexity of the problem: STAFAN does not presently contain thermal coupling, and it is unable to simulate inelastic deformation of the rock mass and variably saturated or two-phase flow in the fractured porous medium system

Preliminary analysis of the potential for thermally-induced rock fracture around high-level waste containers

International Nuclear Information System (INIS)

Ratigan, J.L.

1976-01-01

The major results are: the development of parametric formulations relating the potential for thermally induced fracturing in the high-level radioactive waste repository concept to the elastic and thermal properties of the site rock and the depth of the excavation, and the recognition of a need to determine the actual ''failure envelope'' for any potential site rock in the laboratory and adjust the parametric relations appropriately. Analysis of five rock types indicated that none would experience elastic/brittle failure due to the thermal stresses induced by the introduction of a 5 kW heat source. However, the rock strengths and elastic properties are laboratory values and not in situ values

Rock engineering in Finland

Energy Technology Data Exchange (ETDEWEB)

1986-01-01

Contains a large collection of short articles concerned with tunnels and underground caverns and their construction and use. The articles are grouped under the following headings: use of the subsurface space; water supply; waste water services; energy management (includes articles on power stations, district heating and oil storage and an article on coal storage); multipurpose tunnels; waste disposal; transport; shelters; sporting and recreational amenities located in rock caverns; storage facilities; industrial, laboratory, and service facilities; rock foundations; tourism and culture; utilization of rock masses; research on the disposal of nuclear waste; training and research in the field of rock engineering; site investigation techniques; design of structures in rock; construction; the environment and occupational safety; modern equipment technology; underground space in Helsinki.

Rock mechanics issues and research needs in the disposal of wastes in hydraulic fractures

International Nuclear Information System (INIS)

Doe, T.W.; McClain, W.C.

1984-07-01

The proposed rock mechanics studies outlined in this document are designed to answer the basic questions concerning hydraulic fracturing for waste disposal. These questions are: (1) how can containment be assured for Oak Ridge or other sites; and (2) what is the capacity of a site. The suggested rock mechanics program consists of four major tasks: (1) numerical modeling, (2) laboratory testing, (3) field testing, and (4) monitoring. These tasks are described

Cry from the heart of the nuclear waste heap

International Nuclear Information System (INIS)

Milne, R.

1987-01-01

NIREX, the organisation responsible in the United Kingdom for disposing of radioactive wastes, published a consultation document (Nov 1987) which looks at the options for the disposal of intermediate-level wastes in the UK. The options - under land, under the seabed accessed from the coast, under the seabed accessed at sea - are discussed and their advantages and disadvantages assessed. Possible locations are discussed for geological suitability and public acceptability. The Sellafield site is one possibility being considered. The right combination of site and disposal concept is being sought by NIREX. However, public opinion may not find any option acceptable. (UK)

Solute transport in fractured rock - applications to radionuclide waste repositories

International Nuclear Information System (INIS)

Neretnieks, I.

1990-12-01

Flow and solute transport in fractured rocks has been intensively studied in the last decade. The increased interest is mainly due to the plans in many countries to site repositories for high level nuclear waste in deep geologic formations. All investigated crystalline rocks have been found to be fractured and most of the water flows in the fractures and fracture zones. The water transports dissolved species and radionuclides. It is thus of interest to be able to understand and to do predictive modelling of the flowrate of water, the flowpaths and the residence times of the water and of the nuclides. The dissolved species including the nuclides will interact with the surrounding rock in different ways and will in many cases be strongly retarded relative to the water velocity. Ionic species may be ion exchanged or sorbed in the mineral surfaces. Charges and neutral species may diffuse into the stagnant waters in the rock matrix and thus be withdrawn from the mobile water. These effects will be strongly dependent on how much rock surface is in contact with the flowing water. It has been found in a set of field experiments and by other observations that not all fractures conduct water. Furthermore it is found that conductive fractures only conduct the water in a small part of the fracture in what is called channels or preferential flowpaths. This report summarizes the present concepts of water flow and solute transport in fractured rocks. The data needs for predictive modelling are discussed and both field and laboratory measurement which have been used to obtain data are described. Several large scale field experiments which have been specially designed to study flow and tracer transport in crystalline rocks are described. In many of the field experients new techniques have been developed and used. (81 refs.) (author)

Initial assessment of the thermal stresses around a radioactive waste depository in hard rock

International Nuclear Information System (INIS)

Hodgkinson, D.P.; Bourke, P.J.

1980-01-01

The disposal of heat emitting radioactive waste into hard rock should result in temperature rises and thermal gradients over distances of several hundred metres for several centuries. The consequent constrained thermal expansion of the rock would induce stresses which have important implications for possible water-borne leakage of radionuclides and for depository design. These problems are assessed by considering a simplified mathematical model for which analytic solutions to the temperature and stress fields are derived. (author)

Technical support for GEIS: radioactive waste isolation in geologic formations. Volume 6. Baseline rock properties-shale

International Nuclear Information System (INIS)

1978-04-01

This volume, Y/OWI/TM36/6 Baseline Rock Properties--Shale, is one of a 23-volume series, ''Technical Support for GEIS: Radioactive Waste Isolation in Geologic Formations, Y/OWI/TM-36'' which supplements a ''Contribution to Draft Generic Environmental Impact Statement on Commercial Waste Management: Radioactive Waste Isolation in Geologic Formations, Y/OWI/TM-44.'' The series provides a more complete technical basis for the preconceptual designs, resource requirements, and environmental source terms associated with isolating commercial LWR wastes in underground repositories in salt, granite, shale and basalt. Wastes are considered from three fuel cycles: uranium and plutonium recycling, no recycling of spent fuel and uranium-only recycling. The report is a result of a literature survey of the rock properties of shales occurring in the United States. Firstly, data were collected from a wide variety of sources in order to obtain a feel for the range of properties encountered. Secondly, some typical shales were selected for detailed review and these are written up as separate chapters in this report. Owing to the wide variability in lithology and properties of shales occurring in the United States, it became necessary to focus the study on consolidated illite shales. Using the specific information already generated, a consistent set of intact properties for a typical, consolidated illite shale was obtained. Correction factors, largely based on geological considerations, were then applied to the intact data in order to yield typical rock mass properties for this type of shale. Lastly, excavation problems in shale formations were reviewed and three tunnel jobs were written up as case histories

The disposal of radioactive wastes in Brazil with special emphasis on rocks

International Nuclear Information System (INIS)

Enokihara, Cyro Teiti

1983-01-01

The disposal of radioactive wastes in geological formations seems to be the most appropriate solution for the nuclear waste problem. The disposal sites must provide the maximum safety for the radionuclides during its decay period. The study presents a general analysis of three types rocks: salt, granite and basalt. In our analysis we have dealt with the following aspects: geology, tectonics, seismicity, hydrogeology , mineral resources, geomorphology, population and access. The studied regions were: Sergipe-Alagoas and Reconcavo Basins, Northeastern and Southeastern Folded Regions and Parana Basin. Our study contains the macro-analysis needed for the selection of a safe site for radioactive waste disposal. We believe this work will be useful as a first step for further micro-analysis of selected sites. (author)

MONITORING OF HEAPS USING VARIOUS TECHNOLOGIES

Directory of Open Access Journals (Sweden)

Helena Straková

2015-07-01

Full Text Available Coal heaps are frequently self-burning by definite environmental conditions, therefore thermal activity monitoring of these localities is important. For this purpose, data from terrestrial measurement or thermal infrared images are used. Subsurface coal fires monitored by terrestrial measurement by contact thermometers are time-consuming and dangerous because of landslides. That is a reason why coal fires are mostly monitored by thermal infrared images through remote sensing, i.e. satellite-borne or airborne data, which is much more suitable for thermal activity monitoring. The satellite data do not have sufficient geometric resolution (60 - 120m per pixel, aerial thermal data are accurate, but expensive. Unmanned aerial vehicles (UAV or better RPAS - remotely piloted aircraft systems can be solution – thermal images obtained by RPAS have good geometric resolution and can be used for small areas only and our case project areas are not so big. From economic point of view, low cost technology is preferred. The article describes opportunities of low-cost thermal infrared data, the use of RPAS (mapping by Microkopter system in thermal monitoring and photogrammetric tasks (coal heaps such as low cost aerial thermal mapping. The problems of planning and data acquisition are illustrated by creating an orthophoto. Theoretical preparation of data acquisition deals with RPAS Microkopter mission planning and operation. The obtained data are processed by several sets of software specially developed for close range aerial photogrammetry. The outputs are orthophoto images, digital elevation models and thermal map. As a bonus, low-cost aerial methods with small thermal camera are shown.

Thermal Analysis of a Nuclear Waste Repository in Argillite Host Rock

Science.gov (United States)

Hadgu, T.; Gomez, S. P.; Matteo, E. N.

2017-12-01

Disposal of high-level nuclear waste in a geological repository requires analysis of heat distribution as a result of decay heat. Such an analysis supports design of repository layout to define repository footprint as well as provide information of importance to overall design. The analysis is also used in the study of potential migration of radionuclides to the accessible environment. In this study, thermal analysis for high-level waste and spent nuclear fuel in a generic repository in argillite host rock is presented. The thermal analysis utilized both semi-analytical and numerical modeling in the near field of a repository. The semi-analytical method looks at heat transport by conduction in the repository and surroundings. The results of the simulation method are temperature histories at selected radial distances from the waste package. A 3-D thermal-hydrologic numerical model was also conducted to study fluid and heat distribution in the near field. The thermal analysis assumed a generic geological repository at 500 m depth. For the semi-analytical method, a backfilled closed repository was assumed with basic design and material properties. For the thermal-hydrologic numerical method, a repository layout with disposal in horizontal boreholes was assumed. The 3-D modeling domain covers a limited portion of the repository footprint to enable a detailed thermal analysis. A highly refined unstructured mesh was used with increased discretization near heat sources and at intersections of different materials. All simulations considered different parameter values for properties of components of the engineered barrier system (i.e. buffer, disturbed rock zone and the host rock), and different surface storage times. Results of the different modeling cases are presented and include temperature and fluid flow profiles in the near field at different simulation times. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and

Geotechnical core and rock mass characterization for the UK radioactive waste repository design

International Nuclear Information System (INIS)

Rawlings, C.G.; Barton, N.; Loset, F.; Vik, G.; Bhasin, R.K.; Smallwood, A.; Davies, N.

1996-01-01

The NGI method of characterizing joints (using JRC, JCS and φ r ) and characterizing rock masses (using the Q-system) have been and are currently being used extensively in geotechnical consultancy projects. One such project recently completed for UK Nirex Ltd included the logging of 8 km of 100-mm-diameter drill core from boreholes up to 2km in depth. Preliminary rock reinforcement designs were derived from the Q-system statistics, which were logged in parallel with JRC, JCS and φ r . The data from the NGI method of characterizing joints and the Q-system for characterizing rock masses have also been used as the basis for UDEC-BB numerical modelling of the proposed cavern excavations for the disposal of solid, low- and intermediate-level radioactive wastes. The purpose of this numerical modelling was to investigate the stability of rock caverns and in particular the rock reinforcement requirements (giving predicted bolt loads and rock deformations), the extent of the disturbed zone (joint shearing and hydraulic aperture) with respect to cavern orientation, the effect of various pillar widths, and the effect of the cavern excavation sequence. (Author)

Heap leaching for uranium

International Nuclear Information System (INIS)

1988-01-01

Denison Mines Ltd. is using two bacterial leaching processes to combat the high cost of extracting uranium from low grade ore in thin reefs. Both processes use thiobacillus ferro-oxidans, a bacterium that employs the oxidation of ferrous iron and sulphur as its source of energy for growth. The first method is flood leaching, in which ore is subjected to successive flood, drain and rest cycles. The second, trickle leaching, uses sprinklers to douse the broken muck continuously with leaching solution. In areas where grades are too low to justify the expense of hauling the ore to the surface, the company is using this biological process underground to recover uranium. In 1987 Denison recovered 840 000 lb of uranium through bacterial heap leaching. It plans to have biological in-place leaching contribute 25% of the total uranium production by 1990. (fig.)

Radionuclide transport in fractured rock: quantifying releases from final disposal of high level waste

International Nuclear Information System (INIS)

Silveira, Claudia S. da; Alvim, Antonio C.M.

2013-01-01

Crystalline rock has been considered as a potentially suitable matrix for high-level radioactive waste (HLW) repository because it is found in very stable geological formations and may have very low permeability. In this study the adopted physical system consists of the rock matrix containing a discrete horizontal fracture in a water saturated porous rock and a system of vertical fractures as a lineament. The transport in the fractures - horizontal and vertical, is assumed to obey a relation convection-diffusion, while the molecular diffusion is considered dominant mechanism of transport in porous rock. In this model the decay chain is considered. We use a code in Fortran 90, where the partial differential equations that describe the movement of radionuclides were discretized by finite differences methods. We use the fully implicit method for temporal discretization schemes. The simulation was performed with relevant data of nuclides in spent fuel for performance assessment in a hypothetical repository, thus quantifying the radionuclides released into the host rock. (author)

Influence of convective-energy transfer on calculated temperature distributions in proposed hard-rock nuclear waste repositories

Energy Technology Data Exchange (ETDEWEB)

Eaton, R R; Reda, D C [Sandia National Labs., Albuquerque, NM (USA)

1982-06-01

This study assesses the relative influence of convective-energy transfer on predicted temperature distributions for a nuclear-waste repository located in water-saturated rock. Using results for energy transfer by conduction only (no water motion) as a basis of comparison, it is shown that a considerable amount of energy can be removed from the repository by pumping out water that migrates into the drift from regions adjacent to the buried waste canisters. Furthermore, the results show that the influence of convective-energy transfer on mine drift cooling requirements can be significant for cases where the in-situ permeability of the rock is greater than one millidarcy (a regime potentially encountered in repository scenarios).

A study on nuclide migration in buffer materials and rocks for geological disposal of radioactive waste

International Nuclear Information System (INIS)

Sato, Haruo

1998-01-01

This thesis summarizes the results investigated in order to establish a basic theory on the predictive method of diffusion coefficients of nuclides in compacted sodium bentonite which is a candidate buffer material and in representative rocks for the geological disposal of radioactive waste by measuring the pore structural factors of the compacted bentonite and rocks such as porosity and tortuosity, measuring diffusion coefficients of nuclides in the bentonite and rocks, acquiring basic data on diffusion and developing diffusion models which can quantitatively predict nuclide migration in long-term. (J.P.N.). 117 refs

Heap leach cyanide irrigation and risk to wildlife: Ramifications for the international cyanide management code.

Science.gov (United States)

Donato, D B; Madden-Hallett, D M; Smith, G B; Gursansky, W

2017-06-01

Exposed cyanide-bearing solutions associated with gold and silver recovery processes in the mining industry pose a risk to wildlife that interact with these solutions. This has been documented with cyanide-bearing tailings storage facilities, however risks associated with heap leach facilities are poorly documented, monitored and audited. Gold and silver leaching heap leach facilities use cyanide, pH-stabilised, at concentrations deemed toxic to wildlife. Their design and management are known to result in exposed cyanide-bearing solutions that are accessible to and present a risk to wildlife. Monitoring of the presence of exposed solutions, wildlife interaction, interpretation of risks and associated wildlife deaths are poorly documented. This paper provides a list of critical monitoring criteria and attempts to predict wildlife guilds most at risk. Understanding the significance of risks to wildlife from exposed cyanide solutions is complex, involving seasonality, relative position of ponding, temporal nature of ponding, solution palatability, environmental conditions, in situ wildlife species inventory and provision of alternative drinking sources for wildlife. Although a number of heap leach operations are certified as complaint with the International Cyanide Management Code (Cyanide Code), these criteria are not considered by auditors nor has systematic monitoring regime data been published. Without systematic monitoring and further knowledge, wildlife deaths on heap leach facilities are likely to remain largely unrecorded. This has ramifications for those operations certified as compliance with the Cyanide Code. Copyright © 2017 Elsevier Inc. All rights reserved.

Repository for high level radioactive wastes in Brazil: the importance of geochemical (Micro thermometric) studies and fluid migration in potential host rocks

International Nuclear Information System (INIS)

Rios, Francisco Javier; Fuzikawa, Kazuo; Alves, James Vieira; Neves, Jose Marques Correia

2003-01-01

A detailed fluid inclusion study of host rocks, is of fundamental importance in the selection of geologically suitable areas for high level nuclear waste repository constructions (HLRW). The LIFM-CDTN is enabled to develop studies that confirm: the presence or not, of corrosive fluid in minerals from host rocks of the repository and the possible presence of micro fractures (and fluid leakage) when these rocks are submitted to high temperatures. These fluid geochemistry studies, with permeability determinations by means of pressurized air injection must be carried out in rocks hosting nuclear waste. Micro fracture determination is of vital importance since many naturally corrosive solutions, present in the mineral rocks, could flow out through these plans affecting the walls of the repository. (author)

Heap Leaching Technology. Moving the Frontier for Treatment: Applications in Niger and Namibia

International Nuclear Information System (INIS)

Thiry, Jacques; Bustos, Sergio

2014-01-01

• Uranium is being successfully extracted from low grade ores by heap leaching operations; • The response of the reaction system both at acid or alkaline leaching conditions is well know; • Proper characterization of ore feed is required to anticipate agglomeration quality, heap permeability and stability, and uranium dissolution kinetics and final recovery; • Many laboratory, bench scale tests and pilot plant demonstration at proper scale are necessary to provide suitable design parameters and to fit modeling efforts to actual results; • Large space for optimization opportunities to reduce ore throughput, water and reagents consumption; • Proper effluent solution management and control as well as proper residue disposal are required for safe and clean operation

Disposal of low- and intermediate-level solid radioactive wastes in rock cavities. A guidebook

Energy Technology Data Exchange (ETDEWEB)

1983-01-01

This Guidebook summarizes the factors to be considered and the activities to be undertaken in the overall planning and development of a disposal system for solid or solidified low- and intermediate-level wastes in rock cavities. Aspects related to repository site selection, design, construction, operation, shutdown, surveillance, regulation and safety assessment are discussed here in general terms. They will be covered in greater technical detail in a separate document. This report considers the emplacement of wastes in categories II, III, IV and V, as defined in Table 3.1, in different kinds of cavities located at various depths from just below the surface to deep continental rock. The choice of the type of cavity and its depth and of the disposal site itself is related to the radiological protection requirements for the wastes concerned. The repositories considered include natural caves and abandoned mines as well as specially excavated cavities in various geological formations. Consideration is also given to hydrogeological, environmental and societal factors. The guidelines given in the report are made sufficiently general to cover a broad variety of different circumstances. Consequently, the practical application of these guidelines needs a case-by-case consideration which takes into account the local conditions, e.g. natural circumstances, the characteristics of the wastes and national and international regulations and practices.

Hydrogeochemical assessment of crystaline rock for radioactive waste disposal: the Stripa experience

International Nuclear Information System (INIS)

Andrews, J.; Fontes, J.C.; Fritz, P.; Nordstroem, K.

1988-08-01

This report presents a program for the hydro-geochemical assessment of a crystalline rock site for radioactive waste disposal. It is based upon experience gained during the international program of hydrochemical work at the Stripa mine. The important result of this work are summarized in this report and fuller details may be found in the separate final reports of the Phase 1 and Phase 2 geochemical investigations of the Stripa groundwaters. The present report summarizes the general sampling requirements for a successful hydrochecmical investigation; the isotopic and chemical parameters which should be determined an the geochemical characterization of the rock matrix necessary for the interpretation of hydrochemistry. A general strategy for site evaluation by geochemical methods is presented. (authors)

Geological disposal of high-level radioactive waste and the role of rock engineering

International Nuclear Information System (INIS)

Sugihara, Kozo

2008-01-01

Japan Atomic Energy Agency (JAEA) and its predecessors have been conducting an extensive geoscientific research program since the 1970's in order to contribute to the formation of a firm scientific and technological basis for the geological disposal of high level radioactive waste in Japan. As a part of this program, in situ experiments have been performed at the Tono Mine in soft sedimentary rocks and at the Kamaishi Mine in hard crystalline rocks. An experiment on excavation disturbance has been one of these experiments and has revealed the extent and properties of the excavation disturbed zone (EDZ) and the applicability of available measurement methods. It is suggested that mechanical excavation and controlled excavation have reduced excavation damage of the rock mass around a drift, although some improvements in the currently available methods for measuring and simulating the EDZ are essential to understand excavation disturbance in more detail. JAEA is now promoting two underground research laboratory projects in Japan; the Mizunami Underground Research Laboratory (MIU) project for crystalline rocks and the Horonobe Underground Research Laboratory (Horonobe URL) project for sedimentary rocks. From a rock mechanical point of view, the major interest in these projects will be paid to failure phenomenon deep underground, rock stress estimation at larger scales and long-term physical stability of underground structure. These projects are open for international collaboration. (author)

How did women count? A note on gender-specific age heaping differences in the sixteenth to nineteenth centuries.

Science.gov (United States)

Földvári, Peter; Van Leeuwen, Bas; Van Leeuwen-Li, Jieli

2012-01-01

The role of human capital in economic growth is now largely uncontested. One indicator of human capital frequently used for the pre-1900 period is age heaping, which has been increasingly used to measure gender-specific differences. In this note, we find that in some historical samples, married women heap significantly less than unmarried women. This is still true after correcting for possible selection effects. A possible explanation is that a percentage of women adapted their ages to that of their husbands, hence biasing the Whipple index. We find the same effect to a lesser extent for men. Since this bias differs over time and across countries, a consistent comparison of female age heaping should be made by focusing on unmarried women.

Geotechnical assessment and instrumentation needs for isolation of nuclear waste in crystalline rocks: symposium proceedings

International Nuclear Information System (INIS)

Ubbes, W.F.; Duguid, J.O.

1985-09-01

On October 15-19, 1984, the Geotechnical Assessment and Instrumentation Needs (GAIN) Symposium was convened to examine the status of technology for the isolation of nuclear waste in crystalline rock. The objective of the 1984 GAIN Symposium was to provide technical input to the Crystalline Repository Project concerning: critical issues and information needs associated with development and assessment of a repository in crystalline rock; appropriate techniques and instrumentation for determining the information needed; and technology required to provide the measurement techniques and instrumentation for application in an exploratory shaft in crystalline rock. The findings and recommendations of the symposium are presented in these proceedings

Gabbro as a host rock for a nuclear waste repository

International Nuclear Information System (INIS)

Ahlbom, K.; Leijon, B.; Smellie, J.; Liedholm, M.

1992-09-01

As an alternative to granitic rocks, gabbro and other basic rock types have been investigated with respect to their suitability to host a nuclear waste repository. The present report summarizes and examines existing geoscientific knowledge of relevance in assessing the potential merits of gabbro as a repository host rock. Implications in terms of site selection, repository construction and post-closure repository performance are also discussed. The objective of the study is to provide a basis for decisions as regards future consideration of the gabbro alternative. It is found that there are rather few gabbro bodies in Sweden, that are potentially of sufficient size to host a repository. Thus, gabbro offers little latitude as regards site selection. In comparison to siting a repository in granitic rocks, this is a major disadvantage, and it may in fact remove gabbro from further consideration. The potential advantages of gabbro refer to repository performance, and include low hydraulic conductivity and a chemical environment promoting efficient radionuclide retardation. However, results from field investigations show that groundwater flow in gabbro bodies is largely controlled by intersecting heterogeneities, in particular granitic dykes, that are significantly more conductive to water than the gabbro. In the far-field scale significant to repository performance, this may reduce or eliminate the potential effects of favourable hydraulic and chemical characteristics of the gabbro itself. In conclusion, there are apparent difficulties associated with siting a repository in gabbro, due to lack of sufficiently large gabbro bodies. On the basis of the present state of knowledge, no decisive differences can be demonstrated when comparing gabbro with granitic rocks, neither with respects to repository construction, nor as regards repository performance. (au)

Generalized stress field in granular soils heap with Rayleigh–Ritz method

Directory of Open Access Journals (Sweden)

Gang Bi

2017-02-01

Full Text Available The stress field in granular soils heap (including piled coal will have a non-negligible impact on the settlement of the underlying soils. It is usually obtained by measurements and numerical simulations. Because the former method is not reliable as pressure cells instrumented on the interface between piled coal and the underlying soft soil do not work well, results from numerical methods alone are necessary to be doubly checked with one more method before they are extended to more complex cases. The generalized stress field in granular soils heap is analyzed with Rayleigh–Ritz method. The problem is divided into two cases: case A without horizontal constraint on the base and case B with horizontal constraint on the base. In both cases, the displacement functions u(x, y and v(x, y are assumed to be cubic polynomials with 12 undetermined parameters, which will satisfy the Cauchy's partial differential equations, generalized Hooke's law and boundary equations. A function is built with the Rayleigh–Ritz method according to the principle of minimum potential energy, and the problem is converted into solving two undetermined parameters through the variation of the function, while the other parameters are expressed in terms of these two parameters. By comparison of results from the Rayleigh–Ritz method and numerical simulations, it is demonstrated that the Rayleigh–Ritz method is feasible to study the generalized stress field in granular soils heap. Solutions from numerical methods are verified before being extended to more complicated cases.

Technology needs for selecting and evaluating high-level waste repository sites in crystalline rock

International Nuclear Information System (INIS)

1988-12-01

This report describes properties and processes that govern the performance of the geological barrier in a nuclear waste isolation system in crystalline rock and the state-of-the-art in the understanding of these properties and processes. Areas and topics that require further research and development as well as technology needs for investigating and selecting repository sites are presented. Experiences from the Swedish site selection program are discussed, and a general investigation strategy is presented for an area characterization phase of an exploratory program in crystalline rocks. 255 refs., 65 figs., 10 tabs

Transient diffusion from a waste solid into water-saturated, fractured porous rock

International Nuclear Information System (INIS)

Ahn, J.; Chambre, P.L.; Pigford, T.H.; Lee, W.W.-L.

1989-09-01

Numerical illustrations for transient mass transfer from an infinitely long cylinder intersected by a planar fracture are shown based on Chambre's exact analytical solutions. The concentration at the cylinder surface is maintained at the solubility. In the fracture contaminant diffuses in the radial direction. In the rock matrix three-dimensional diffusion is assumed in the cylindrical coordinate. No advection is assumed. Radioactive decay and sorption equilibrium are included. Radioactive decay enhances the mass transfer from the cylinder. Due to the presence of the fracture, the mass flux from the cylinder to the rock matrix becomes smaller, but the fracture effect is limited in the vicinity of the fracture in early times. Even though the fracture is assumed to be a faster diffusion path than the rock matrix, the larger waste surface exposed to the matrix and the greater assumed matrix sorption result in greater release rate to the matrix than to the fracture. 8 refs., 4 figs

A feasibility study to determine the functionality of a novel rocking kiln - fluidized bed reactor for the treatment of waste

International Nuclear Information System (INIS)

Mohamad Azman Che Mat Isa; Muhd Noor Muhd Yunus; Mohamad Puad Abu; Shahazrin Mohd Nasir; Mohd fairus Abdul Farid

2004-01-01

Rotary kiln has been widely used in incineration and studied by many researches. Solid wastes of various shapes, sizes and heat value can be fed into rotary kiln either in batches or continually. Waste combustion in rotary kiln involves rotation method and the residence time depends on the length and diameter of the rotary kiln and the total stoichiometric air given to the system. Rocking system is another technology used in incinerator. In the rocking system, internal elements in the combustion chamber move to transports and mix the burning waste so that all combustible material in the waste is fully burnt. Another technology in incinerator is the fluidized bed This method uses air to fluidized the sand thus enhancing the combustion process. The total air is controlled in order to obtain a suitable fluidized condition This preliminary study was conducted to study the feasibility of an incinerator system when three components viz. the rotary kiln, rocking system and fluidized bed are combined This research was also conducted to obtain preliminary data parameters of the three components such as the suitable temperature, the angle of the kiln, residence time, total air for fluidization, rocking speed and the devolatilization rate. The samples used in this research were the palm oil kernel shells. The results of the studies showed that the palm oil kernel shells combusted evenly using the new parameters. (Author)

Preparation of soda-lime glass using rock wool waste; Preparacao de vidros sodo-calcicos utilizando residuo de la de rocha

Energy Technology Data Exchange (ETDEWEB)

Aleixo, F.C.; Della, V.P. [Instituto Federal do Espirito Santo, Vitoria, ES (Brazil); Ballmann, T.J.S.; Folgueras, M.V. [Universidade do Estado de Santa Catarina (UESC), Joinville, SC (Brazil); Junkes, J.A., E-mail: janajunkes@gmail.com [Centro Universitario Tiradentes, Maceio, AL (Brazil)

2016-10-15

Discarded by the mining industry during the maintenance stoppages of pelletizing furnaces, rock wool has in its composition SiO{sub 2} (56%), Na{sub 2} O (12%) and CaO (7%) propitious for obtaining soda-lime glasses. Under this focus, this work developed soda-lime glasses formulations, using as main raw-material rock wool waste in proportions from 50 to 100% by adjusting the chemical composition of the formulations with sand, sodium and calcium carbonates, as silica, soda and lime sources, respectively. In some formulations the sodium carbonate was replaced by sodium sulfate, which acts as a refining agent, improving homogenization and reducing the bubble formation during the melting. Initially, the raw-materials were evaluated by X-ray fluorescence, X-ray diffraction, differential thermal analysis, and thermogravimetric analysis. The tests showed that the rock wool waste has potential to be used in soda-lime glasses production, however, the chemical composition must be corrected. After knowing the waste potential, seven mixtures were prepared and molten at 1550 °C for 1 to 2 h. It has been found that the maximum rock wool waste percentage that can be used is between 60 and 80%, and that the 2 h melting time resulted in more homogeneous glasses and fewer bubbles according to the addition of sodium sulfate which is efficient for bubbles removal. (author)

Comparison of thermally induced and naturally occurring water-borne leakages from hard rock depositories for radioactive waste

International Nuclear Information System (INIS)

Bourke, P.J.; Robinson, P.C.

1981-01-01

The relative importance of thermally induced and naturally occurring flows of water as causes of leakage from hard rock depositories for radioactive wastes is assessed. Separate analyses are presented for involatile, high level waste from reprocessing of fuel and for plutonium contaminated waste from fabrication of fuel. The effects of varying the quantities of wastes, pre-burial storage and the shapes and depths of depositories are considered. It is concluded that for representative values of these variables, thermal flow will remain the major cause of leakage for long times after the burial of both types of waste. (Auth.)

Chemical buffering capacity of clay rock

International Nuclear Information System (INIS)

Beaucaire, C.; Pearson, F.J.; Gautschi, A.

2004-01-01

The long-term performance of a nuclear waste repository is strongly dependent on the chemical properties of the host rock. The host rock establishes the chemical environment that determines such important performance attributes as radionuclide solubilities from the waste and the transport rates from the repository to the accessible environment. Clay-rich rocks are especially favourable host rocks because they provide a strong buffering capacity to resist chemical changes prompted either internally, by reactions of the waste itself and emplacement materials, or externally, by changes in the hydrologic systems surrounding the host rock. This paper will focus on three aspects of the stability of clay-rich host rocks: their ability to provide pCO 2 and redox buffering, and to resist chemical changes imposed by changes in regional hydrology and hydro-chemistry. (authors)

Water - rock interaction in different rock environments

International Nuclear Information System (INIS)

Lamminen, S.

1995-01-01

The study assesses the groundwater geochemistry and geological environment of 44 study sites for radioactive waste disposal. Initially, the study sites were divided by rock type into 5 groups: (1) acid - intermediate rocks, (2) mafic - ultramafic rocks, (3) gabbros, amphibolites and gneisses that contain calc-silicate (skarn) rocks, (4) carbonates and (5) sandstones. Separate assessments are made of acid - intermediate plutonic rocks and of a subgroup that comprises migmatites, granite and mica gneiss. These all belong to the group of acid - intermediate rocks. Within the mafic -ultramafic rock group, a subgroup that comprises mafic - ultramafic plutonic rocks, serpentinites, mafic - ultramafic volcanic rocks and volcanic - sedimentary schists is also evaluated separately. Bedrock groundwaters are classified by their concentration of total dissolved solids as fresh, brackish, saline, strongly saline and brine-class groundwaters. (75 refs., 24 figs., 3 tabs.)

Qualitative evaluation of various models for mechanical analysis of nuclear wastes storage in brittle rocks

International Nuclear Information System (INIS)

Millard, A.

1994-01-01

In order to appraise the large scale behaviour of high level nuclear wastes underground repositories in brittle rocks, basic models are presented and evaluated in the case of generic repository configurations. Predictive Capabilities of the models are briefly discussed. 7 figs

Seismic response of rock joints and jointed rock mass

International Nuclear Information System (INIS)

Ghosh, A.; Hsiung, S.M.; Chowdhury, A.H.

1996-06-01

Long-term stability of emplacement drifts and potential near-field fluid flow resulting from coupled effects are among the concerns for safe disposal of high-level nuclear waste (HLW). A number of factors can induce drift instability or change the near-field flow patterns. Repetitive seismic loads from earthquakes and thermal loads generated by the decay of emplaced waste are two significant factors. One of two key technical uncertainties (KTU) that can potentially pose a high risk of noncompliance with the performance objectives of 10 CFR Part 60 is the prediction of thermal-mechanical (including repetitive seismic load) effects on stability of emplacement drifts and the engineered barrier system. The second KTU of concern is the prediction of thermal-mechanical-hydrological (including repetitive seismic load) effects on the host rock surrounding the engineered barrier system. The Rock Mechanics research project being conducted at the Center for Nuclear Waste Regulatory Analyses (CNWRA) is intended to address certain specific technical issues associated with these two KTUs. This research project has two major components: (i) seismic response of rock joints and a jointed rock mass and (ii) coupled thermal-mechanical-hydrological (TMH) response of a jointed rock mass surrounding the engineered barrier system (EBS). This final report summarizes the research activities concerned with the repetitive seismic load aspect of both these KTUs

The role of the disturbed rock zone in radioactive waste repository safety and performance assessment. A topical discussion and international overview

International Nuclear Information System (INIS)

Winberg, A.

1991-06-01

A discussion was presented of the role and relative importance of the disturbed rock zone (DRZ) around the underground openings of a repository for nuclear waste in crystalline rock. The term disturbed rock zone was defined and possible criteria to be sued to distinguish if from undisturbed rock was suggested. The processes decisive for the hydraulic characteristics of the DRZ were discussed. With regard to the integral hydraulic characteristics of the DRZ, the effects of the excavation methodology, stress redistribution, thermal changes, chemical changes and backfill were discussed. A review of in-situ observations of the DRZ was provided. Model analysis where the DRZ has been explicitly or implicitly represented, either from a phenomenological and performance assessment aspect were reviewed. The implications of the disturbed rock zone for the safe performance of a nuclear waste repository were discussed. Conceptual models for the geometry of the DRZ and hydraulic conductivity distribution in the DRZ were suggested. (au) (82 refs.)

DESIGN AND ANALYSIS OF AN EXPERIMENT FOR ASSESSING CYANIDE IN GOLD MINING WASTES

Science.gov (United States)

Gold mining wastes treated by heap leaching cyanidization typically contain several metallo-cyanide species. Accurate measurement of total cyanide by the most common methods in such a case may be hampered by the inadequate recoveries that occur for certain cyanide compounds (e.g....

Combined DC resistivity and induced polarization (DC-IP) for mapping the internal composition of a mine waste rock pile in Nova Scotia, Canada

Science.gov (United States)

Power, Christopher; Tsourlos, Panagiotis; Ramasamy, Murugan; Nivorlis, Aristeidis; Mkandawire, Martin

2018-03-01

Mine waste rock piles (WRPs) can contain sulfidic minerals whose interaction with oxygen and water can generate acid mine drainage (AMD). Thus, WRPs can be a long-term source of environmental pollution. Since the generation of AMD and its release into the environment is dependent on the net volume and bulk composition of waste rock, effective characterization of WRPs is necessary for successful remedial design and monitoring. In this study, a combined DC resistivity and induced polarization (DC-IP) approach was employed to characterize an AMD-generating WRP in the Sydney Coalfield, Nova Scotia, Canada. Two-dimensional (2D) DC-IP imaging with 6 survey lines was performed to capture the full WRP landform. 2D DC results indicated a highly heterogeneous and moderately conductive waste rock underlain by a resistive bedrock containing numerous fractures. 2D IP (chargeability) results identified several highly-chargeable regions within the waste, with normalized chargeability delineating regions specific to waste mineralogy only. Three-dimensional (3D) DC-IP imaging, using 17 parallel lines on the plateau of the pile, was then used to focus on the composition of the waste rock. The full 3D inverted DC-IP distributions were used to identify coincident and continuous zones (isosurfaces) of low resistivity (0.4 mS/m) that were inferred as generated AMD (leachate) and stored AMD (sulfides), respectively. Integrated geological, hydrogeological and geochemical data increased confidence in the geoelectrical interpretations. Knowledge on the location of potentially more reactive waste material is extremely valuable for improved long-term AMD monitoring at the WRP.

Radon emission from uranium mining waste rock dumps and resulting radon immission; Radonemissionsverhalten von Halden des Uranbergbaus und daraus resultierende Radonemissionen

Energy Technology Data Exchange (ETDEWEB)

Regner, J.; Hinz, W.; Schmidt, P. [Wismut GmbH, Chemnitz (Germany)

2016-07-01

Since more than 20 years, Wismut GmbH has been investigating the radon situation at uranium mining waste rock dumps. In the present paper the results of 19 complex studies at uranium mining dumps in the Erzgebirge (Ore Mountains) are reported. Although the mean specific activity of Ra-226 of the waste rock material was on a rather low level of about 0.5 Bq/g, the mean radon concentration in free atmosphere at the public exposure sites in the immediate vicinity of the dumps reached a value of about 1000 Bq/m{sup 3} for a half-year exposition and of about 600 Bq/m{sup 3} for a one-year exposition. Certain geometries and structures of waste rock dumps and the occurrence of convective airflows in the dumps are main reasons for the high radon emission despite of the relatively low specific Ra-226 activity. A case study for two buildings directly on the top of a waste rock dump in the town Johanngeorgenstadt is presented. The hypothetical interpolation of the results for Ra-226-activity to a value below the threshold value of 0.2 Bq/g leads to the assumption that problematic radon situations may also occur outside the areas of legacies of uranium mining. Considering the aspects mentioned, a clearance level for NORM of 1 Bq/g is questionable.

The accumulation of elements in plants growing spontaneously on small heaps left by the historical Zn-Pb ore mining.

Science.gov (United States)

Stefanowicz, Anna M; Stanek, Małgorzata; Woch, Marcin W; Kapusta, Paweł

2016-04-01

The study evaluated the levels of nine metals, namely Ca, Cd, Fe, K, Mg, Mn, Pb, Tl, and Zn, in soils and tissues of ten plant species growing spontaneously on heaps left by historical mining for Zn-Pb ores. The concentrations of Cd, Pb, Tl, and Zn in heap soils were much higher than in control soils. Plants growing on heaps accumulated excessive amounts of these elements in tissues, on average 1.3-52 mg Cd kg(-1), 9.4-254 mg Pb kg(-1), 0.06-23 mg Tl kg(-1) and 134-1479 mg Zn kg(-1) in comparison to 0.5-1.1 mg Cd kg(-1), 2.1-11 mg Pb kg(-1), 0.02-0.06 mg Tl kg(-1), and 23-124 mg Zn kg(-1) in control plants. The highest concentrations of Cd, Pb, and Zn were found in the roots of Euphorbia cyparissias, Fragaria vesca, and Potentilla arenaria, and Tl in Plantago lanceolata. Many species growing on heaps were enriched in K and Mg, and depleted in Ca, Fe, and Mn. The concentrations of all elements in plant tissues were dependent on species, organ (root vs. shoot), and species-organ interactions. Average concentrations of Ca, K, and Mg were generally higher in shoots than in roots or similar in the two organs, whereas Cd, Fe, Pb, Tl, and Zn were accumulated predominantly in the roots. Our results imply that heaps left by historical mining for Zn-Pb ores may pose a potential threat to the environment and human health.

Impact of bimodal textural heterogeneity and connectivity on flow and transport through unsaturated mine waste rock

Science.gov (United States)

Appels, Willemijn M.; Ireson, Andrew M.; Barbour, S. Lee

2018-02-01

Mine waste rock dumps have highly variable flowpaths caused by contrasting textures and geometry of materials laid down during the 'plug dumping' process. Numerical experiments were conducted to investigate how these characteristics control unsaturated zone flow and transport. Hypothetical profiles of inner-lift structure were generated with multiple point statistics and populated with hydraulic parameters of a finer and coarser material. Early arrival of water and solutes at the bottom of the lifts was observed after spring snowmelt. The leaching efficiency, a measure of the proportion of a resident solute that is flushed out of the rock via infiltrating snowmelt or rainfall, was consistently high, but modified by the structure and texture of the lift. Under high rates of net percolation during snowmelt, preferential flow was generated in coarse textured part of the rock, and solutes in the fine textured parts of the rock remained stagnant. Under lower rates of net percolation during the summer and fall, finer materialswere flushed too, and the spatial variability of solute concentration in the lift was reduced. Layering of lifts leads to lower flow rates at depth, minimizing preferential flow and increased leaching of resident solutes. These findings highlight the limited role of large scale connected geometries on focusing flow and transport under dynamic surface net percolation conditions. As such, our findings agree with recent numerical results from soil studies with Gaussian connected geometries as well as recent experimental findings, emphasizing the dominant role of matrix flow and high leaching efficiency in large waste rock dumps.

Radiological hazards of TENORM in precipitated calcium carbonate generated as waste at nitrophosphate fertilizer plant in Pakistan

Energy Technology Data Exchange (ETDEWEB)

Javied, Sabiha, E-mail: sabihajavied@yahoo.com [Pakistan Institute of Engineering and Applied Sciences (PIEAS), Nilore 45650, Islamabad (Pakistan); Akhtar, Nasim [Nuclear Institute for Agriculture and Biology (NIAB), Jhang Road, Faisalabad (Pakistan); Tufail, M. [Pakistan Institute of Engineering and Applied Sciences (PIEAS), Nilore 45650, Islamabad (Pakistan)

2011-08-15

Highlights: {yields} NORM (naturally occurring radioactive material) in phosphate rock (PR) is converted to TENORM (technologically enhanced naturally occurring radioactive material) as a result of chemical processing of the PR to make phosphate fertilizers. {yields} Precipitated calcium carbonate (PCC) is generated as process waste during nitrophosphate fertilizer production, which contains TENORM. {yields} Activity concentration of the radionuclide in the TENORM was measured using gamma spectrometry and radiological hazard was derived from the measured activities. {yields} Radiological pollution in the environment from TENORM in the PCC has been addressed. {yields} Restricted application of the PCC dose not pose a significant radiological hazard. -- Abstract: The NORM (naturally occurring radioactive material) in phosphate rock is transferred as TENORM (technologically enhanced naturally occurring radioactive material) to phosphatic fertilizers and to the waste generated by the chemical processes. The waste generated at the NP (nitrophosphate) fertilizer plant at Multan in Pakistan is PCC (precipitated calcium carbonate). Thirty samples of the PCC were collected from the heaps of the waste near the fertilizer plant. Activity concentrations of radionuclides in the waste samples were measured by using the technique of gamma ray spectrometry consisting of coaxial type HPGe (high purity germanium) detector coupled with a PC (personal computer) based MCA (multichannel analyzer) through a spectroscopy amplifier. Activity concentrations of {sup 226}Ra, {sup 232}Th and {sup 40}K in the waste samples were determined to be 273 {+-} 23 (173-398), 32 {+-} 4 (26-39) and 56 {+-} 5 (46-66) Bq kg{sup -1} respectively. The activity concentration of {sup 226}Ra in the PCC waste was found to be higher than that in naturally occurring calcium carbonate (limestone and marble) and in worldwide soil. Radiological hazard was estimated from indoor and outdoor exposure to gamma rays from

Role of hydrogen ions in standard and activation heap leaching of gold

Science.gov (United States)

Rubtsov, YuI

2017-02-01

The role of hydrogen ions in activation heap leaching of gold from rebellious ore has been studied, which has allowed enhancing gold recovery. The author puts forward a gold leaching circuit with the use of activated oxygen-saturated solutions acidified to pH = 6-9.

Review of potential host rocks for radioactive waste disposal in the Piedmont province of North Carolina

International Nuclear Information System (INIS)

Butler, J.R.

1980-10-01

This report reviews the geology of the Piedmont province in North Carolina, emphasizing those features most pertinent to selection of potential host rocks for radioactive waste disposal. Discussion of criteria for selection indicates that the outcrop area of the rock body, probable homogeneity, low incidence of fractures, and low permeability are among the prime considerations. Application of the criteria leads to the selection of three large granite batholiths (Castalia, Churchland, and Rolesville) as potential field study areas. The report has an extensive bibliography

Earthworm succession in afforested colliery spoil heaps in the Sokolov region, Czech Republic

Czech Academy of Sciences Publication Activity Database

Pižl, Václav

2001-01-01

Roč. 9, č. 4 (2001), s. 359-364 ISSN 1061-2971 Institutional research plan: CEZ:AV0Z6066911 Keywords : earthworms * colliery spoil heaps * succession Subject RIV: EH - Ecology, Behaviour Impact factor: 1.011, year: 2001

Heap bioleaching of uranium from low-grade granite-type ore by mixed acidophilic microbes

International Nuclear Information System (INIS)

Xuegang Wang; Zhongkui Zhou

2017-01-01

We evaluated uranium bioleaching from low-grade, granite-type uranium ore using mixed acidophilic microbes from uranium mine leachate. A 4854-ton plant-scale heap bioleaching process achieved sustained leaching with a uranium leaching efficiency of 88.3% using a pH of 1.0-2.0 and an Fe"3"+ dosage of 3.0-5.5 g/L. Acid consumption amounted to 25.8 g H_2SO_4 kg"-"1 ore. Uranium bioleaching follows a diffusion-controlled kinetic model with a correlation coefficient of 0.9136. Almost all uranium was dissolved in aqueous solution, except those encapsulated in quartz particles. Therefore, heap bioleaching by mixed acidophilic microbes enables efficient, economical, large-scale recovery of uranium from low-grade ores. (author)

Rock solidification method

International Nuclear Information System (INIS)

Nakaya, Iwao; Murakami, Tadashi; Miyake, Takafumi; Funakoshi, Toshio; Inagaki, Yuzo; Hashimoto, Yasuhide.

1985-01-01

Purpose: To convert radioactive wastes into the final state for storage (artificial rocks) in a short period of time. Method: Radioactive burnable wastes such as spent papers, cloths and oils and activated carbons are burnt into ashes in a burning furnace, while radioactive liquid wastes such as liquid wastes of boric acid, exhausted cleaning water and decontaminating liquid wastes are powderized in a drying furnace or calcining furnace. These powders are joined with silicates as such as white clay, silica and glass powder and a liquid alkali such as NaOH or Ca(OH) 2 and transferred to a solidifying vessel. Then, the vessel is set to a hydrothermal reactor, heated and pressurized, then taken out about 20 min after and tightly sealed. In this way, radioactive wastes are converted through the hydrothermal reactions into aqueous rock stable for a long period of time to obtain solidification products insoluble to water and with an extremely low leaching rate. (Ikeda, J.)

Proceedings of workshop 5: Flow and transport through unsaturated fractured rock -- related to high-level radioactive waste disposal

International Nuclear Information System (INIS)

Evans, D.D.; Nicholson, T.J.

1993-06-01

The ''Workshop on Flow and Transport Through Unsaturated Fractured Rock Related to High-Level Radioactive Waste Disposal'' was cosponsored by the NRC, the Center for Nuclear Waste Regulatory Analyses, and the University of Arizona (UAZ) and was held in Tucson, Arizona, on January 7--10, 1991. The focus of this workshop, similar to the earlier four (the first being in 1982), related to hydrogeologic technical issues associated with possible disposal of commercial high-level nuclear waste (HLW) in a geologic repository within an unsaturated fractured rock system which coincides with the UAZ field studies on HLW disposal. The presentations and discussions centered on flow and transport processes and conditions, relevant parameters, as well as state-of-the-art measurement techniques, and modeling capabilities. The workshop consisted of: four half-day technical meetings, a one day field visit to the Apache Leap test site to review ongoing field studies that are examining site characterization techniques and developing data sets for model validation studies, and a final half-day session devoted to examining research needs related to modeling groundwater flow and radionuclide transport in unsaturated, fractured rock. These proceedings provide extended abstracts of the technical presentations and short summaries of the research group reports

The use of borehole geophysical logs and hydrologic tests to characterize plutonic rock for nuclear fuel waste disposal

International Nuclear Information System (INIS)

Davison, C.C.

1984-05-01

The selection of an igneous rock body for the disposal of nuclear fuel waste will likely require the drilling and testing of a number of deep investigative boreholes in the rock body. Although coring of at least one hole at each Research Area will be essential, methods for making in situ geophysical and hydrological measurements can substitute for widespread coring and result in significant savings in time and money. A number of borehole methods have been applied to the investigation of plutonic rocks at Whiteshell Nuclear Research Establishment and Chalk River Nuclear Laboratories in Canada

Numerical modeling of the geomechanical response of a rock mass to a radioactive waste repository

International Nuclear Information System (INIS)

Hardy, M.P.; St John, C.M.; Hocking, G.

1979-06-01

Geotechnical numerical models capable of predicting the thermomechanical response and groundwater movements around an underground radioactive waste repository are vital to the success of the nuclear waste disposal program. In the absence of directly related engineering experience, the design, risk assessment, and licensing procedures of a repository will be reliant on predictions made using such models. This paper reviews models being used to assist in repository design and summarizes the results of a recent parametric study of underground disposal in basaltic rocks. On the basis of preliminary site data, it is concluded that the allowable areal density of heat-generating waste will be controlled by the stability of placement rooms and the boreholes in which waste canisters are placed. Regional effects including thermally induced upward groundwater flow, appear to present less severe problems

Estimates of water and solute release from a coal waste rock dump in the Elk Valley, British Columbia, Canada.

Science.gov (United States)

Villeneuve, S A; Barbour, S L; Hendry, M J; Carey, S K

2017-12-01

Long term (1999 to 2014) flow and water quality data from a rock drain located at the base of a coal waste rock dump constructed in the Elk Valley, British Columbia was used to characterize the release of three solutes (NO 3 - , Cl - and SO 4 2- ) from the dump and obtain whole dump estimates of net percolation (NP). The concentrations of dump derived solutes in the rock drain water were diluted by snowmelt waters from the adjacent natural watershed during the spring freshet and reached a maximum concentration during the winter baseflow period. Historical peak baseflow concentrations of conservative ions (NO 3 - and Cl - ) increased until 2006/07 after which they decreased. This decrease was attributed to completion of the flushing of the first pore volume of water stored within the dump. The baseflow SO 4 2- concentrations increased proportionally with NO 3 - and Cl - to 2007, but then continued to slowly increase as NO 3 - and Cl - concentrations decreased. This was attributed to ongoing production of SO 4 2- due to oxidation of sulfide minerals within the dump. Based on partitioning of the annual volume of water discharged from the rock drain to waste rock effluent (NP) and water entering the rock drain laterally from the natural watershed, the mean NP values were estimated to be 446±50mm/a (area normalized net percolation/year) for the dump and 172±71mm/a for the natural watershed. The difference was attributed to greater rates of recharge in the dump from summer precipitation compared to the natural watershed where rainfall interception and enhanced evapotranspiration will increase water losses. These estimates included water moving through subsurface pathways. However, given the limitations in quantifying these flows the estimated NP rates for both the natural watershed and the waste rock dump are considered to be low, and could be much higher (e.g. ~450mm/a and ~800mm/a). Copyright © 2017 Elsevier B.V. All rights reserved.

Rock & Roll : Waste seperation

NARCIS (Netherlands)

Beunder, L.; Rem, P.C.; Van Den Berg, R.

2000-01-01

Five hundred tonnes of glass, 1 million tonnes of plastic,14 million tonnes of building and demolition waste, 7 million tonnes of household waste, 3 million tonnes of packaging, 3.5 million tonnes of paper and board, and 300,000 old cars. All part of the annual harvest of waste materials in the

Waste/Rock Interactions Technology Program: the status of radionuclide sorption-desorption studies performed by the WRIT program

International Nuclear Information System (INIS)

Serne, R.J.; Relyea, J.F.

1982-04-01

The most credible means for radionuclides disposed as solid wastes in deep-geologic repositories to reach the biosphere is through dissolution of the solid waste and subsequent radionuclide transport by circulating ground water. Thus safety assessment activities must consider the physicochemical interactions between radionculides present in ground water with package components, rocks and sediments since these processes can significantly delay or constrain the mass transport of radionuclides in comparison to ground-water movement. This paper focuses on interactions between dissolved radiouclides in ground water and rocks and sediments away from the near-field repository. The primary mechanism discussed is adsorption-desorption, which has been studied using two approaches. Empirical studies of adsorption-desorption rely on distribution coefficient measurements while mechanism studies strive to identify, differentiate and quantify the processes that control nuclide retardation

Controls on Weathering of Pyrrhotite in a Low-Sulfide, Granitic Mine-Waste Rock in the Canadian Arctic

Science.gov (United States)

Langman, J. B.; Holland, S.; Sinclair, S.; Blowes, D.

2013-12-01

Increased environmental risk is incurred with expansion of mineral extraction in the Arctic. A greater understanding of geochemical processes associated with hard-rock mining in this cold climate is needed to evaluate and mitigate these risks. A laboratory and in-situ experiment was conducted to examine mineral weathering and the generation of acid rock drainage in a low-sulfide, run-of-mine waste rock in an Arctic climate. Rock with different concentrations of sulfides (primarily pyrrhotite [Fe7S8] containing small amounts of Co and Ni) and carbonates were weathered in the laboratory and in-situ, large-scale test piles to examine leachate composition and mineral weathering. The relatively larger sulfide-containing rock produced sufficient acid to overcome carbonate buffering and produced a declining pH environment with concomitant release of SO4, Fe, Co, and Ni. Following carbonate consumption, aluminosilicate buffering stabilized the pH above 4 until a reduction in acid generation. Results from the laboratory experiment assisted in determining that after consumption of 1.6 percent of the total sulfide, the larger sulfide-concentration test pile likely is at an internal steady-state or maximal weathering rate after seven years of precipitation input and weathering that is controlled by an annual freeze-thaw cycle. Further weathering of the test pile should be driven by external factors of temperature and precipitation in this Arctic, semi-arid region instead of internal factors of wetting and non-equilibrium buffering. It is predicted that maximal weathering will continue until at least 20 percent of the total sulfide is consumed. Using the identified evolution of sulfide consumption in this Arctic climate, a variable rate factor can now be assessed for the possible early evolution and maximal weathering of larger scale waste-rock piles and seasonal differences because of changes in the volume of a waste-rock pile undergoing active weathering due to the freeze

Questa baseline and pre-mining ground-water quality investigation. 19. Leaching characteristics of composited materials from mine waste-rock piles and naturally altered areas near Questa, New Mexico

Science.gov (United States)

Smith, Kathleen S.; Hageman, Philip L.; Briggs, Paul H.; Sutley, Stephen J.; McCleskey, R. Blaine; Livo, K. Eric; Verplanck, Philip L.; Adams, Monique G.; Gemery-Hill, Pamela A.

2007-01-01

The goal of this study is to compare and contrast the leachability of metals and the acidity from individual mine waste-rock piles and natural erosional scars in the study area near Questa, New Mexico. Surficial multi-increment (composite) samples less than 2 millimeters in diameter from five waste-rock piles, nine erosional-scar areas, a less-altered site, and a tailings slurry-pipe sample were analyzed for bulk chemistry and mineralogy and subjected to two back-to-back leaching procedures. The first leaching procedure, the U.S. Geological Survey Field Leach Test (FLT), is a short-duration leach (5-minute shaking and 10-minute settling) and is intended to leach readily soluble materials. The FLT was immediately followed by an 18-hour, end-over-end rotation leaching procedure. Comparison of results from the back-to-back leaching procedures can provide information about reactions that may take place upon migration of leachates through changing geochemical conditions (for example, pH changes), both within the waste-rock and scar materials and away from the source materials. For the scar leachates, the concentrations of leachable metals varied substantially between the scar areas sampled. The scar leachates have low pH (pH 3.2-4.1). Under these low-pH conditions, cationic metals are solubilized and mobile, but anionic species, such as molybdenum, are less soluble and less mobile. Generally, metal concentrations in the waste-rock leachates did not exceed the upper range of those metal concentrations in the erosional-scar leachates. One exception is molybdenum, which is notably higher in the waste-rock leachates compared with the scar leachates. Most of the waste-rock leachates were at least mildly acidic (pH 3.0-6.2). The pH values in the waste-rock leachates span a large pH range that includes some pH-dependent solubility and metal-attenuation reactions. An increase in pH with leaching time and agitation indicates that there is pH-buffering capacity in some of the

Creep in the sparsely fractured rock between a disposal vault and a zone of highly fractured rock

International Nuclear Information System (INIS)

Wilkins, B.J.S.; Rigby, G.L.

1993-08-01

AECL Research is responsible for investigating the feasibility and safety of the disposal of Canada's nuclear fuel waste deep in the plutonic rock of the Canadian Shield. The excavation of the disposal vault, the installation of sealing systems and the heat generated by the fuel waste will all perturb the in situ stress state of the rock mass. This computer codes HOTROK, MCROC and MCDIRC are used to analyze the influence of these stress perturbations on the mechanical behaviour of the rock mass. Time-dependent microcracking of the rock mass will lead to creep around openings in the vault. The analysis specifically estimates the resulting creep strain in the sparsely fractured rock between the edge of the disposal vault and a postulated zone of highly fractured rock. The estimates are extremely conservative. The conclusion reached is that the rock mass more than 3 m beyond the edge of the vault will experience < 0.001 creep strain 100 000 years after the fuel waste is emplaced. (author). 10 refs., 4 tabs., 4 figs

Growth rate characteristics of acidophilic heterotrophic organisms from mine waste rock piles

Science.gov (United States)

Yacob, T. W.; Silverstein, J.; Jenkins, J.; Andre, B. J.; Rajaram, H.

2010-12-01

Autotrophic iron oxidizing bacteria play a key role in pyrite oxidation and generation of acid mine drainage AMD. Scarcity of organic substrates in many disturbed sites insures that IOB have sufficient oxygen and other nutrients for growth. It is proposed that addition of organic carbon substrate to waste rock piles will result in enrichment of heterotrophic microorganisms limiting the role of IOB in AMD generation. Previous researchers have used the acidophilic heterotroph Acidiphilium cryptum as a model to study the effects of organic substrate addition on the pyrite oxidation/AMD cycle. In order to develop a quantitative model of effects such as competition for oxygen, it is necessary to use growth and substrate consumption rate expressions, and one approach is to choose a model strain such as A. cryptum for kinetic studies. However we have found that the growth rate characteristics of A. cryptum may not provide an accurate model of the remediation effects of organic addition to subsurface mined sites. Fluorescent in-situ hybridization (FISH) assays of extracts of mine waste rock enriched with glucose and yeast extract did not produce countable numbers of cells in the Acidiphilium genus, with a detection limit of3 x 104 cells/gram rock, despite evidence of the presence of well established heterotrophic organisms. However, an MPN enrichment produced heterotrophic population estimates of 1x107 and 1x109 cells/gram rock. Growth rate studies of A. cryptum showed that cultures took 120 hours to degrade 50% of an initial glucose concentration of 2,000 mg/L. However a mixed culture enriched from mine waste rock consumed 100% of the same amount of glucose in 24 hours. Substrate consumption data for the mixed culture were fit to a Monod growth model: {dS}/{dt} = μ_{max}S {( {X_0}/{Y} + S_0 -S )}/{(K_s +S)} Kinetic parameters were estimated utilizing a non linear regression method coupled with an ODE solver. The maximum specific growth rate of the mixed population with �

A theoretical and numerical consideration of rock mass behaviour under thermal loading of radioactive waste repository

International Nuclear Information System (INIS)

Reivinen, M.; Freund, J.; Eloranta, E.

1996-08-01

The aim of the study is to model the geodynamic response of a ground rock block under horizontal stresses and also consider the thermal fields and deformations, especially on the ground surface, caused by the heat produced by nuclear waste. (12 refs.)

Recent studies on radiation damage formation in synthetic NaCl and natural rock salt for radioactive waste disposal applications

International Nuclear Information System (INIS)

Swyler, K.J.; Klaffky, R.W.; Levy, P.W.

1980-01-01

Radiation damage formation in natural rock salt is described as a function of irradiation temperature and plastic deformation. F-center formation decreases with increasing temperature while significant colloidal sodium formation occurs over a restricted temperature range around 150 0 C. Plastic deformation increases colloid formation; it is estimated that colloid concentrations may be increased by a factor of 3 if the rock salt near radioactive waste disposal canisters is heavily deformed. Optical bandshape analysis indicates systematic differences between the colloids formed in synthetic and natural rock salts

Geophysical study in waste landfill localized above fractured rocks

Directory of Open Access Journals (Sweden)

Ariveltom Cosme da Silva

2011-08-01

Full Text Available Geophysical survey is an important method for investigation of contaminated areas used in the characterization of contrasting physical properties in the presence of pollutants. This work applied the geophysical methods of Electrical Resistivity and Self Potential in waste landfill, located in Caçapava do Sul city, RS. The landfill is located over fractured metamorphic rocks. Eight lines of electrical profiling with 288 measures of self potential were done. In addition, 83 measurements of direction and dip of fractures were taken. The application of spontaneous potential method permitted to detect the direction of groundwater flow. The electrical resistivity measurements allowed the identification of low-intensity anomalies associated with the presence of leachate. There is a relationship between anomalous zones and the directions of fractures.

Importance of creep failure of hard rock in the near field of a nuclear-waste repository

International Nuclear Information System (INIS)

Blacic, J.D.

1981-01-01

Potential damage resulting from slow creep deformation intuitively seems unlikely for a high-level nuclear waste repository excavated in hard rock. However, recent experimental and modeling results indicate that the processes of time-dependent microcracking and water-induced stress corrosion can lead to significant reductions in strength and alteration of other key rock properties in the near-field region of a repository. We review the small data base supporting these conclusions and stress the need for an extensive laboratory program to obtain the new data that will be required for design of a repository

Importance of creep failure of hard rock in the near field of a nuclear waste repository

Energy Technology Data Exchange (ETDEWEB)

Blacic, J D [Los Alamos National Laboratory, NM, (USA)

1982-12-31

Potential damage resulting from slow creep deformation intuitively seems unlikely for a high-level nuclear waste repository excavated in hard rock. However, recent experimental and modeling results indicate that the processes of time-dependent microcracking and water-induced stress corrosion can lead to significant reductions in strength and alteration of other key rock properties in the near-field region of a repository. We review the small data base supporting these conclusions and stress the need for an extensive laboratory program to obtain the new data that will be required for design of a repository.

Building a Uranium Heap Leach Project

International Nuclear Information System (INIS)

Schnell, Henry

2014-01-01

Despite all these we have seen many HL successes and many interesting projects coming down the pipe. • Previous experience in Uranium with previous ROM projects in France (Bessines, Langone), Niger (Somair), Canada (Agnew Lake) and other locations had provided some basic background. • Heap leach based on copper experience with crushed ore has operated for many years in Brazil (Caetite). • Many gold operations for many decades in all climates and continents. • Copper at +20% of production, many in Chile, but also now in many other countries. • Uranium with agglomerated crushed ores is now becoming more prominent – Somair, Imouraren, Trekkopje. • Work also ongoing for Ranger, Rossing, and in consideration for other projects. • Other notable work in Nickel, and multi-metal such as Talvivaara

Possibility of Radioactive and Toxic WasteDisposal in a Rock Ssalt Deposits in Slovakia Combining Wells and Cavities

Directory of Open Access Journals (Sweden)

Škvareková Erika

2004-09-01

Full Text Available Disposal of radioactive and toxic waste in rock salt can be performed in two ways – disposal in the salt mine repository or disposal in the deep wells connected with salt cavity. Presented article deals with the option of the disposal in a salt cavity at medium depths. The article also cover partially salt deposits in Slovakia and their potential suitability for waste disposal..

The TIMODAZ project: Thermal impact on the damaged zone around a radioactive waste disposal in clay host rocks

International Nuclear Information System (INIS)

XiangLing, L.

2009-01-01

The management of spent nuclear fuel and other long-lived radio active waste is an important environmental issue today. Disposal in deep clay geological formations is one of the promising options to dispose of these wastes. In this context, the related research activities in the Euratom Framework Programme of European Commission are continually taking on an enhanced significance. The TIMODAZ is one of the STREP projects (Specific Targeted Research Project) in the Sixth EURATOM Framework Programme and contributes to the research related to the geological disposal of radioactive waste. The consortium is composed of a strong multidisciplinary team involving both European radioactive waste management organizations and nuclear research institutes, universities, industrial partners as well as consultancy companies (SME's). Totally, 15 partners coming from 8 countries are involved with a total budget of about 4000k EURO. Being the coordinator (through the EURIDICE expertise group), SCK-CEN plays the leading role in the project. Meanwhile, SCK-CEN participates the research in different work packages covering the laboratory tests, in-situ tests as well as the integration of TIMODAZ results within the safety case. An important item for the long-term safety of underground disposal is the proper evaluation of the DZ (damaged zone) in the clay host rock. The DZ is defined here as the zone of host rock that experiences THMC (Thermo-Hydro-Mechanical-Chemical) modifications induced by the repository, with potential major changes in the transport properties for radionuclides. The DZ is first initiated during the repository construction. Its behaviour is dynamic, dependent on changing conditions that vary from the open-drift period, to initial closure period and to the entire heating-cooling cycle of the decaying waste. The early THMC disturbances created by the excavation, the operational phase and the thermal load might be the most severe transient that the repository will undergo

Investigations of Near-Field Thermal-Hydrologic-Mechanical-Chemical Models for Radioactive Waste Disposal in Clay/Shale Rock

Energy Technology Data Exchange (ETDEWEB)

Liu, H.H.; Li, L.; Zheng, L.; Houseworth, J.E.; Rutqvist, J.

2011-06-20

Clay/shale has been considered as potential host rock for geological disposal of high-level radioactive waste throughout the world, because of its low permeability, low diffusion coefficient, high retention capacity for radionuclides, and capability to self-seal fractures. For example, Callovo-Oxfordian argillites at the Bure site, France (Fouche et al., 2004), Toarcian argillites at the Tournemire site, France (Patriarche et al., 2004), Opalinus Clay at the Mont Terri site, Switzerland (Meier et al., 2000), and Boom clay at the Mol site, Belgium (Barnichon and Volckaert, 2003) have all been under intensive scientific investigation (at both field and laboratory scales) for understanding a variety of rock properties and their relationships to flow and transport processes associated with geological disposal of radioactive waste. Figure 1-1 presents the distribution of clay/shale formations within the USA.

Investigations of Near-Field Thermal-Hydrologic-Mechanical-Chemical Models for Radioactive Waste Disposal in Clay/Shale Rock

International Nuclear Information System (INIS)

Liu, H.H.; Li, L.; Zheng, L.; Houseworth, J.E.; Rutqvist, J.

2011-01-01

Clay/shale has been considered as potential host rock for geological disposal of high-level radioactive waste throughout the world, because of its low permeability, low diffusion coefficient, high retention capacity for radionuclides, and capability to self-seal fractures. For example, Callovo-Oxfordian argillites at the Bure site, France (Fouche et al., 2004), Toarcian argillites at the Tournemire site, France (Patriarche et al., 2004), Opalinus Clay at the Mont Terri site, Switzerland (Meier et al., 2000), and Boom clay at the Mol site, Belgium (Barnichon and Volckaert, 2003) have all been under intensive scientific investigation (at both field and laboratory scales) for understanding a variety of rock properties and their relationships to flow and transport processes associated with geological disposal of radioactive waste. Figure 1-1 presents the distribution of clay/shale formations within the USA.

Improvement for waste water treatment process of a uranium deposite and its effect

International Nuclear Information System (INIS)

Huang Jimao

2013-01-01

Uranium was recovered from alkaline uranium ores by heap leaching and traditional agitation leaching methods at a uranium mine, and the waste water (including waste water produced in hydrometallurgy process and mine drainage) was treated by using chemical precipitation method and chemical precipitation loading method. It was found that the removal rate of uranium by the waste water treatment process was not satisfactory after one year's run. So, the waste water treatment process was improved. After the improvement, removal rate of CO 3 2- ,HCO 3 - , U and Ra was enhanced and the treated waste water reached the standard of discharge. (author)

Geological assessment of crystalline rock formations with a view to radioactive waste disposal

International Nuclear Information System (INIS)

Mather, J.D.

1984-01-01

Field work has been concentrated at the Altnabreac Research Site on north-east Scotland, where three deep boreholes to approximately 300 m and 24 shallow boreholes to approximately 40 m were drilled. The movement of groundwater within 300 m of the surface was investigated using a specially developed straddle packer system. Geochemical studies have demonstrated that most groundwater is dominated by recent recharge but one borehole yielded water with an age of around 10 4 years. Geophysical borehole logging has shown that the full wave train sonic logs and the acoustic logs show most promise for the assessment of crystalline rocks. In the laboratory the interaction of rocks and groundwater at the temperature/pressure conditions to be expected in a repository has established the geochemical environment to which waste canisters and backfill materials would be subjected. Other generic studies reported include the characterization of geotechnical properties of rocks at elevated temperatures and pressures, the development of a new cross-hole sinusoidal pressure test for the measurement of hydraulic properties and the use of thermal infra-red imagery to detect groundwater discharge zones

Host Rock Classification (HRC) system for nuclear waste disposal in crystalline bedrock

International Nuclear Information System (INIS)

Hagros, A.

2006-01-01

A new rock mass classification scheme, the Host Rock Classification system (HRC-system) has been developed for evaluating the suitability of volumes of rock mass for the disposal of high-level nuclear waste in Precambrian crystalline bedrock. To support the development of the system, the requirements of host rock to be used for disposal have been studied in detail and the significance of the various rock mass properties have been examined. The HRC-system considers both the long-term safety of the repository and the constructability in the rock mass. The system is specific to the KBS-3V disposal concept and can be used only at sites that have been evaluated to be suitable at the site scale. By using the HRC-system, it is possible to identify potentially suitable volumes within the site at several different scales (repository, tunnel and canister scales). The selection of the classification parameters to be included in the HRC-system is based on an extensive study on the rock mass properties and their various influences on the long-term safety, the constructability and the layout and location of the repository. The parameters proposed for the classification at the repository scale include fracture zones, strength/stress ratio, hydraulic conductivity and the Groundwater Chemistry Index. The parameters proposed for the classification at the tunnel scale include hydraulic conductivity, Q' and fracture zones and the parameters proposed for the classification at the canister scale include hydraulic conductivity, Q', fracture zones, fracture width (aperture + filling) and fracture trace length. The parameter values will be used to determine the suitability classes for the volumes of rock to be classified. The HRC-system includes four suitability classes at the repository and tunnel scales and three suitability classes at the canister scale and the classification process is linked to several important decisions regarding the location and acceptability of many components of

Characterization of crystalline rocks in the Lake Superior region, USA: implications for nuclear waste isolation

International Nuclear Information System (INIS)

Sood, M.K.; Flower, M.F.J.; Edgar, D.E.

1984-01-01

The Lake Superior region (Wisconsin, the Upper Peninsula of Michigan, and Minnesota) contains 41 Precambrian crystalline rock complexes comprising 64 individual but related rock bodies with known surface exposures. Each complex has a map area greater than 78 km 2 . About 54% of the rock complexes have areas of up to 500 km 2 , 15% fall between 500 km 2 and 1000 km 2 , 19% lie between 1000 km 2 and 2500 km 2 , and 12% are over 2500 km 2 . Crystalline rocks of the region vary widely in composition, but they are predominantly granitic. Repeated thermo-tectonic events have produced early Archean gneisses, migmatites, and amphibolites with highly tectonized fabrics that impart a heterogeneous and anisotropic character to the rocks. Late Archean rocks are usually but not invariably gneissose and migmatitic. Proterozoic rocks of the region include synorogenic (foliated) granitic rocks, anorogenic (non-foliated) granites, and the layered gabbro-anorthosite-troctolite intrusives of the rift-related Keweenawan igneous activity. Compared with the Archean rocks of the region, the Proterozoic bodies generally lack highly tectonized fabrics and have more definable contacts where visible. Anorogenic intrusions are relatively homogeneous and isotropic. On the basis of observed geologic characteristics, postorogenic and anorogenic crystalline rock bodies located away from recognized tectonic systems have attributes that make them relatively more desirable as a possible site for a nuclear waste repository in the region. This study was conducted at Argonne National Laboratory under the sponsorship of the US Department of Energy through the Office of Crystalline Repository Development at Battelle Memorial Institute, Columbus, Ohio. 84 references, 4 figures, 3 tables

Characterization of crystalline rocks in the Lake Superior region, USA: implications for nuclear waste isolation

International Nuclear Information System (INIS)

Sood, M.K.; Edgar, D.E.; Flower, M.F.J.

1984-01-01

The Lake Superior region (Wisconsin, the Upper Peninsula of Michigan, and Minnesota) contains 41 Precambrian crystalline (medium- to coarse-grained igneous and high-grade metamorphic) rock complexes comprising 64 individual but related rock bodies with known surface exposures. Each complex has a map area greater than 78 km 2 . About 54% of the rock complexes have areas of up to 500 km 2 , 15% fall between 500 km 2 and 1000 km 2 , 19% lie between 1000 km 2 and 2500 km 2 , and 12% are over 2500 km 2 . Crystalline rocks of the region vary widely in composition, but they are predominantly granitic. Repeated thermo-tectonic events have produced early Archean gneisses, migmatites, and amphibolites with highly tectonized fabrics that impart a heterogeneous and anisotropic character to the rocks. Late Archean rocks are usually but not invariably gneissose an migmatitic. Proterozoic rocks of the region include synorogenic (foliated) granitic rocks, anorogenic (nonfoliated) granites, and the layered gabbro-anorthosite-troctolite intrusives of the rift-related Keweenawan igneous activity. Compared with the Archean rocks of the region, the Proterozoic bodies generally lack highly tectonized fabrics and have more definable contacts where visible. Anorogenic intrusions are relatively homogeneous and isotropic. On the basis of observed geologic characteristics, postorogenic and anorogenic crystalline rock bodies located away from recognized tectonic systems have attributes that make them relatively more desirable as a possible site for a nuclear waste repository in the region. This study was conducted at Argonne National Laboratory under the sponsorship of the US Department of Energy through the Office of Crystalline Repository Development at Battelle Memorial Institute, Columbus, Ohio

Concepts and Technologies for Radioactive Waste Disposal in Rock Salt

Directory of Open Access Journals (Sweden)

Wernt Brewitz

2007-01-01

Full Text Available In Germany, rock salt was selected to host a repository for radioactive waste because of its excellent mechanical properties. During 12 years of practical disposal operation in the Asse mine and 25 years of disposal in the disused former salt mine Morsleben, it was demonstrated that low-level wastes (LLW and intermediate-level wastes (ILW can be safely handled and economically disposed of in salt repositories without a great technical effort. LLW drums were stacked in old mining chambers by loading vehicles or emplaced by means of the dumping technique. Generally, the remaining voids were backfilled by crushed salt or brown coal filter ash. ILW were lowered into inaccessible chambers through a borehole from a loading station above using a remote control.Additionally, an in-situ solidification of liquid LLW was applied in the Morsleben mine. Concepts and techniques for the disposal of heat generating high-level waste (HLW are advanced as well. The feasibility of both borehole and drift disposal concepts have been proved by about 30 years of testing in the Asse mine. Since 1980s, several full-scale in-situ tests were conducted for simulating the borehole emplacement of vitrified HLW canisters and the drift emplacement of spent fuel in Pollux casks. Since 1979, the Gorleben salt dome has been investigated to prove its suitability to host the national final repository for all types of radioactive waste. The “Concept Repository Gorleben” disposal concepts and techniques for LLW and ILW are widely based on the successful test operations performed at Asse. Full-scale experiments including the development and testing of adequate transport and emplacement systems for HLW, however, are still pending. General discussions on the retrievability and the reversibility are going on.

Basic investigation and analysis for preferred host rocks and natural analogue study area with reference to high level radioactive waste disposal

Energy Technology Data Exchange (ETDEWEB)

Seo, Jeong Ryul; Park, J. K.; Hwang, D. H.; Lee, J. H.; Yun, H. S.; Kim, D. Y.; Park, H. S.; Koo, S. B.; Cho, J. D.; Kim, K. E. [Korea Inst. of Geology, Mining and Materials, Taejon (Korea, Republic of)

1997-12-01

The purpose of this study is basic investigation and analysis for preferred host rocks and natural analogue study area to develope underground disposal technique of high level radioactive waste in future. The study has been done for the crystalline rocks(especially granitic rocks) with emphasis of abandoned metallic mines and uranium ore deposits, and for the geological structure study by using gravity and aeromagnetic data. 138 refs., 54 tabs., 130 figs. (author)

Modeling of a sedimentary rock alternative for the siting of the radioactive waste disposal system

International Nuclear Information System (INIS)

Fuentes, Nestor O.

2007-01-01

Here are described the main concepts, the approximations, and all those simulation aspects that characterize the modeling performed using the unsaturated saturated approach for porous media. The objective of this work is to obtain a generic description of a sedimentary rock soil as an alternative site for the low and intermediate level radioactive waste disposal system. (author) [es

Site investigation methods used in Canada's nuclear fuel waste management program to determine the hydrogeological conditions of plutonic rock

International Nuclear Information System (INIS)

Davison, C.C.

1985-01-01

Atomic Energy of Canada Limited (AECL) is investigating the concept of disposing of Canada's nuclear fuel wastes in a mined vault at a depth of 500 m to 1000 m within a plutonic rock body. Much effort has been directed at developing site investigation methods that can be used to determine the hydrogeological conditions of plutonic rock bodies. The primary objective of this research is to define the physical and chemical characteristics of groundwater flow systems at the various scales that are relevant to the prediction of potential radionuclide migration from a disposal vault. Groundwater movement through plutonic rock is largely controlled by fractures within the rock, and the hydrogeological parameters of fractured geological media are extremely scale dependent

Nuclear waste disposal

International Nuclear Information System (INIS)

Lindblom, U.; Gnirk, P.

1982-01-01

The subject is discussed under the following headings: the form and final disposal of nuclear wastes; the natural rock and groundwater; the disturbed rock and the groundwater; long-term behavior of the rock and the groundwater; nuclear waste leakage into the groundwater; what does it all mean. (U.K.)

Radionuclide Transport in Fractured Rock: Numerical Assessment for High Level Waste Repository

Directory of Open Access Journals (Sweden)

Claudia Siqueira da Silveira

2013-01-01

Full Text Available Deep and stable geological formations with low permeability have been considered for high level waste definitive repository. A common problem is the modeling of radionuclide migration in a fractured medium. Initially, we considered a system consisting of a rock matrix with a single planar fracture in water saturated porous rock. Transport in the fracture is assumed to obey an advection-diffusion equation, while molecular diffusion is considered the dominant mechanism of transport in porous matrix. The partial differential equations describing the movement of radionuclides were discretized by finite difference methods, namely, fully explicit, fully implicit, and Crank-Nicolson schemes. The convective term was discretized by the following numerical schemes: backward differences, centered differences, and forward differences. The model was validated using an analytical solution found in the literature. Finally, we carried out a simulation with relevant spent fuel nuclide data with a system consisting of a horizontal fracture and a vertical fracture for assessing the performance of a hypothetical repository inserted into the host rock. We have analysed the bentonite expanded performance at the beginning of fracture, the quantified radionuclide released from a borehole, and an estimated effective dose to an adult, obtained from ingestion of well water during one year.

THM-coupled modeling of selected processes in argillaceous rock relevant to rock mechanics

International Nuclear Information System (INIS)

Czaikowski, Oliver

2012-01-01

Scientific investigations in European countries other than Germany concentrate not only on granite formations (Switzerland, Sweden) but also on argillaceous rock formations (France, Switzerland, Belgium) to assess their suitability as host and barrier rock for the final storage of radioactive waste. In Germany, rock salt has been under thorough study as a host rock over the past few decades. According to a study by the German Federal Institute for Geosciences and Natural Resources, however, not only salt deposits but also argillaceous rock deposits are available at relevant depths and of extensions in space which make final storage of high-level radioactive waste basically possible in Germany. Equally qualified findings about the suitability/unsuitability of non-saline rock formations require fundamental studies to be conducted nationally because of the comparatively low level of knowledge. The article presents basic analyses of coupled mechanical and hydraulic properties of argillaceous rock formations as host rock for a repository. The interaction of various processes is explained on the basis of knowledge derived from laboratory studies, and open problems are deduced. For modeling coupled processes, a simplified analytical computation method is proposed and compared with the results of numerical simulations, and the limits to its application are outlined. (orig.)

Use of overburden rocks from open-pit coal mines and waste coals of Western Siberia for ceramic brick production with a defect-free structure

Science.gov (United States)

Stolboushkin, A. Yu; Ivanov, A. I.; Storozhenko, G. I.; Syromyasov, V. A.; Akst, D. V.

2017-09-01

The rational technology for the production of ceramic bricks with a defect-free structure from coal mining and processing wastes was developed. The results of comparison of physical and mechanical properties and the structure of ceramic bricks manufactured from overburden rocks and waste coal with traditional for semi-dry pressing mass preparation and according to the developed method are given. It was established that a homogeneous, defect-free brick texture obtained from overburden rocks of open-pit mines and waste coal improves the quality of ceramic wall materials produced by the method of compression molding by more than 1.5 times compared to the brick with a traditional mass preparation.

Five-year performance monitoring of a high-density polyethylene (HDPE) cover system at a reclaimed mine waste rock pile in the Sydney Coalfield (Nova Scotia, Canada).

Science.gov (United States)

Power, Christopher; Ramasamy, Murugan; MacAskill, Devin; Shea, Joseph; MacPhee, Joseph; Mayich, David; Baechler, Fred; Mkandawire, Martin

2017-12-01

Cover systems are commonly placed over waste rock piles (WRPs) to limit atmospheric water and oxygen ingress and control the generation and release of acid mine drainage (AMD) to the receiving environment. Although covers containing geomembranes such as high-density polyethylene (HDPE) exhibit the attributes to be highly effective, there are few, if any, published studies monitoring their performance at full-scale WRPs. In 2011, a HDPE cover was installed over the Scotchtown Summit WRP in Nova Scotia, Canada, and extensive field performance monitoring was conducted over the next five years. A range of parameters within the atmosphere, cover, waste rock, groundwater and surface water, were monitored and integrated into a comprehensive hydrogeochemical conceptual model to assess (i) atmospheric ingress to the waste rock, (ii) waste rock acidity and depletion and (iii) evolution of groundwater and surface water quality. Results demonstrate that the cover is effective and meeting site closure objectives. Depletion in oxygen influx resulted in slower sulphide oxidation and AMD generation, while a significant reduction in water influx (i.e. 512 to 50 mm/year) resulted in diminished AMD release. Consistent improvements in groundwater quality (decrease in sulphate and metals; increase in pH) beneath and downgradient of the WRP were observed. Protection and/or significant improvement in surface water quality was evident in all surrounding watercourses due to the improved groundwater plume and elimination of contaminated runoff over previously exposed waste rock. A variably saturated flow and contaminant transport model is currently being developed to predict long-term cover system performance.

Parameter-sensitivity analysis of near-field radionuclide transport in buffer material and rock for an underground nuclear fuel waste vault

International Nuclear Information System (INIS)

Cheung, S.C.H.; Chan, T.

1983-08-01

An analytical model has been developed for radionuclide transport in the vicinity of a nuclear fuel waste container emplaced in a borehole. The model considers diffusion in the buffer surrounding the waste container, and both diffusion and groundwater convection in the rock around the borehole. A parameter-sensitivity analysis has been done to study the effects on radionuclide flux of (a) Darcian velocity of groundwater in the rock, (b) effective porosity of the buffer, (c) porosity of the rock, (d) radial buffer thickness, and (e) radius and length of the container. It is found that the radionuclide flux, Fsub(R), and the total integrated flux, Fsub(T), are greater for horizontal flow than for vertical flow; Fsub(R) decreases with increasing radial buffer thickness for all Darcian velocities, whereas Fsub(T) decreases at high velocities but increases at low velocities. The rate of change of Fsub(R) and of Fsub(T) decreases with decreasing flow velocity and increasing buffer thickness; Fsub(R) is greater for higher effective porosity of buffer or rock; and Fsub(R) increases and Fsub(T) decreases with decreasing container radius or length

Review of potential host rocks for radioactive waste disposal in the southeast United States: Southeastern Coastal Plain Subregion

International Nuclear Information System (INIS)

1980-10-01

A literature review was made of the geological characteristics of the Southeastern Coastal Plain physiograhic province in the states of Maryland, Virginia, North Carolina, South Carolina, and Georgia. The purpose of this study was to identify candidate exploration areas for the possible location of a mined repository for the storage of radioactive waste in the argillaceous sedimentary rocks of the Coastal Plain. Candidate areas were selected on the basis of geological characteristics, available subsurface data, and generally accepted requirements for waste isolation developed by previous studies. Factors considered in the evaluation include the stratigraphy and lithology, geologic history, structure, seismicity, hydrogeology, and natural resources of the candidate area. Unlike other potential regions, the Southeastern Coastal Plain is not composed of competent rock, but consists primarily of unconsolidated and water-saturated sediments overlying a basement of crystalline and metavolcanic rocks. Thus, construction of both shafts and tunnels to depths of approx. 1000 meters may encounter difficulties. Socio-economic and construction considerations have not been addressed in the evaluation. Based on the applied criteria, four areas were selected as being most favorable for future field investigation. These include one in Maryland, one in North Carolina, and two in Georgia

Interim guidelines on performance constraints for nuclear waste disposal in crystalline rock

International Nuclear Information System (INIS)

1984-01-01

Performance constraint guidelines have been developed for geologic disposal of nuclear waste in crystalline rock. The approach taken in defining these guidelines was to consider the thermal, thermomechanical, and thermochemical behavior for three regions (very-near field, near field, and far field) of the repository during three time periods (operational, containment, and isolation) associated with the disposal system. Limits are proposed to ensure compliance with the current repository criteria proposed by the United States Nuclear Regulatory Commission (NRC) concerning repository siting and performance assessment. These criteria are: Substantial containment of all radionuclides within the waste package for a period of time between 300 and 1000 years after emplacement. Release rate after loss of containment of one part in 100,000 annually per radionuclide based on the nuclides inventory when the waste package is breached, and in situ ground-water transit time of 1000 years from the repository horizon to the accessible environment, compliance with the performance constraint guidelines presented herein will be required to ensure that the final repository design is in compliance with NRC criteria. The constraint guidelines have also been developed to satisfy the requirement for technical conservatism. 40 refs., 14 figs., 4 tabs

Modelling of thermo-hydro-mechanical couplings and damage of viscoplastic rocks in the context of radioactive waste storage

International Nuclear Information System (INIS)

Kharkhour, H.

2002-12-01

Trying to develop a model taking into account the complex rheology of a geologic media characterized by visco-plasticity, damage and thermo-hydro-mechanical couplings is unusual in geotechnics. This is not the case for radioactive waste storage that presents specificities from several viewpoints. Indeed, the scales of time and space concerned by this type of storage are disproportionate to those of civil engineering works or mines. Another specificity of the radioactive waste storage lies in the coupled processes involved. No effect likely to compromise the long-term security of the storage could be ignored. For example this is the case of damage, a phenomenon which does not necessarily lead to a major change of the mechanical behavior of the works but can influence the permeability of the medium in relation with a migration of radionuclides. It can be conceived that this phenomenon finds all its importance in the context of the thermo-hydro-mechanical couplings of a waste storage with high activity. However, the interaction between the damage and the THM coupled processes was the object of very few research subject up to now. This. is even more true for viscoplastic media considered as ductile, and therefore, less prone to cracking than brittle media. It is exactly in this 'original' but difficult context that took place the research presented in this report. This study was dedicated to the analysis of the phenomena and the thermal, hydraulic and mechanical couplings occurring in the near and far field of a high activity radioactive waste storage. Two examples of geological media were considered in this report: the clayey rock of Callovo-Oxfordian, called ' Argilites de l'Est ', target rock of the ANDRA project to carry out a subterranean laboratory for the study of long life radioactive waste storage; and the salt rock of the. subterranean laboratory in the old salt mine of Asse in Germany. (author)

Rationale for geological isolation of high-level radioactive waste, and assessment of the suitability of crystalline rocks

International Nuclear Information System (INIS)

Smedes, H.W.

1980-01-01

This report summarizes the disposal objective to be met and the requisite geotechnical criteria to meet that objective; evaluates our present ability to determine whether certain criteria can be met and to predict whether they will continue to be met; discusses the consequences of failure to meet certain criteria; assesses what is known about how crystalline rocks meet those criteria; lists important gaps in our knowledge that presently preclude final assessment of suitability; and suggests priority research to fill those gaps. The report presents an elaboration of the above-stated behavior and suitability of crystalline rocks, and a rationale of site-selection in support of the recommended prompt and intensive study of granite and other crystalline rocks as potentially highly suitable candidate media for radioactive waste disposal. An overview is presented on what the rocks are, where they are, and what the critical attributes are of various crystalline-rock terranes in the conterminous United States. This is intended to provide a basis to aid in selecting, first regions, and then sites within those regions, as candidate repository sites

Review of potential host rocks for radioactive waste disposal in the Piedmont Province of Virginia and Maryland

International Nuclear Information System (INIS)

Brown, W.R.

1980-10-01

This study is a detailed follow-up of a broad study of the Southeastern Piedmont by Acres American, Inc. (1978) based upon literature and existing knowledge. The purpose is to designate broad areas in which the rock type is favorable for field exploration for the possible designation of a site for disposal of solidified radioactive waste. The Acres study classified rock units as favorable, potentially favorable, and unfavorable. The objective of the present study is: (1) to review the criteria used in this classification, and (2) on the basis of a detailed knowledge of local rock units to reassign the rock types in the potentially favorable category to either the favorable or the unfavorable categories. As in the Acres study, the objective is to designate field study areas, not potential sites. This study was based entirely upon a literature study, discussions with persons knowledgeable of the region, and a personal acquaintance with the rocks and structures. No field work was done specifically for this project. No consideration was given to sociological, economic, or non-technical factors

Site selection and general layout of heap leaching uranium mill

International Nuclear Information System (INIS)

Zhang Chunmao; Rongfeng

2011-01-01

The site selection and general layout of uranium mill is an important work in the design and consultation stage of uranium mining and metallurgy's engineering construction. Based on the design practices, the principles and methods for the site selection and general layout of heap leaching uranium mill are analyzed and studied. Some problems which should be paid much attention to in the design are discussed in hopes of providing a useful reference for the design and consultation of similar projects. (authors)

Thermomigration of fluid inclusions in rock salt. Implications for the disposal of nuclear wastes

International Nuclear Information System (INIS)

Noack, W.; Runge, K.

1984-01-01

A mathematical model has been suggested to predict the time-dependent accumulation of brine at nuclear waste packages emplaced in a rock salt repository owing to thermomigration of brine inclusions. The model is based mainly on a description of the migration rate as a function of the temperature, temperature gradient, inclusion size and gas/liquid ratio of inclusions. Other factors are treated merely as disturbing quantities with respect to the migration rate. (author)

Thin-layer heap bioleaching of copper flotation tailings containing high levels of fine grains and microbial community succession analysis

Science.gov (United States)

Hao, Xiao-dong; Liang, Yi-li; Yin, Hua-qun; Liu, Hong-wei; Zeng, Wei-min; Liu, Xue-duan

2017-04-01

Thin-layer heap bioleaching of copper flotation tailings containing high levels of fine grains was carried out by mixed cultures on a small scale over a period of 210 d. Lump ores as a framework were loaded at the bottom of the ore heap. The overall copper leaching rates of tailings and lump ores were 57.10wt% and 65.52wt%, respectively. The dynamic shifts of microbial community structures about attached microorganisms were determined using the Illumina MiSeq sequencing platform based on 16S rRNA amplification strategy. The results indicated that chemolithotrophic genera Acidithiobacillus and Leptospirillum were always detected and dominated the microbial community in the initial and middle stages of the heap bioleaching process; both genera might be responsible for improving the copper extraction. However, Thermogymnomonas and Ferroplasma increased gradually in the final stage. Moreover, the effects of various physicochemical parameters and microbial community shifts on the leaching efficiency were further investigated and these associations provided some important clues for facilitating the effective application of bioleaching.

Radioactive waste storage in mined caverns in crystalline rock: results of field investigations at Stripa, Sweden

International Nuclear Information System (INIS)

Witherspoon, P.A.

1980-10-01

It is generally agreed that the most practicable method of isolating nuclear wastes from the biosphere is by deep burial in suitable geologic formations. Such burial achieves a high degree of physical isolation but raises questions concerning the rate at which some of these wastes may return to the biosphere through transport by groundwater. Any suitable repository site will be disturbed first by excavation and second by the thermal pulse caused by the radioactive decay of the wastes. To assess the effectiveness of geologic isolation it is necessary to develop the capability of predicting the response of a rock mass to such a thermal pulse. Ultimately, this requires field measurements below the surface in media representative of those likely to be encountered at an actual repository. Access to a granitic rock mass adjacent to a defunct iron ore mine at Stripa, Sweden, at a depth of about 350 m below surface has provided a unique opportunity to conduct a comprehensive suite of hydrological and thermo-mechanical experiments under such conditions. The results of these field tests have shown the importance of geologic structure and the functional dependence of the thermo-mechanical properties on temperature in developing a valid predictive model. The results have also demonstrated the vital importance of carrying out large-scale investigations in a field test facility

Investigation results on water quality and volume of flowing-in water to the Yotsugi slag heap site. 2

International Nuclear Information System (INIS)

Naganuma, Masaki; Taki, Tomihiro; Takimoto, Sadao; Makita, A.

2000-05-01

Mining water flowing into the Yotsugi slag heap site at the Ningyo-toge Environment Technical Center is exhausted to a common river after carrying out the treatment of uranium and radium in the mining water at the previously settled mining water treatment facility and confirming it to be less than management target value on the river water within the site boundary regulated by the agreement on environmental conservation with Okayama prefecture and Kami-saihara mura. In order to elucidate some required treatment on every water system flowing-in the heap site as a part of reduction of flowing volume on taking action of the heap site, an investigation on its water quality and volume was carried out. As a result, it was confirmed on water quality that uranium values of every river were all less than their target values but radium values of them were all over their target values which necessitated conventional water treatment. And, on water volume, it was confirmed that flowing water volume from the exposed excavation site was reduced about 40% in comparison with same rain-fall before removing from rain water. (G.K.)

Biomembrane oxidizing tank used in the process of bacterial heap leaching of uranium ore

International Nuclear Information System (INIS)

Meng Yunsheng; Fan Baotuan; Liu Jian; Zheng Ying; Liu Chao

2004-01-01

The construction characteristic of biomembrane oxidizing tank and specialty of packing material used in the process of bacterial heap leaching of uranium ore are introduced in this paper. Method for designing biomembrane oxidizing tank, layout principle of aeration system and measurements on running management are summarized

Role of HHM coupling mechanisms on the evolution of rock masses around nuclear waste disposals in the context of gas generation

International Nuclear Information System (INIS)

Hoxha, D.; Do, D.-P.; Wendling, J.; Poutrel, A.

2010-01-01

Document available in extended abstract form only. This paper aims at modelling of long term evolution of hydro-mechanical state of rock masses around sealing nuclear waste disposals. In the principles of nuclear waste disposals the geological barrier must play a long term confining role in respect with nuclide transport. In terms of hydro-mechanical properties this calls for managing the damage around the underground workings of the waste disposals. In particular the seal buffers and barrier rock will support the generation of hydrogen of different origins, mainly from the corrosion of steals used in various elements of a nuclear waste disposal. This generation would generate gas pressures sufficiently high to partially dry seal or barrier rock leading to a redistribution of stress around underground openings, to a reactivation of the rock damage and finally could put in question the concept of geological barrier itself. The object of this paper is to shed light in the mechanisms of HHM coupling in rocks around a repository by comparative numerical analyses. Basically, we chose two configurations to proceed with analyses: one in plan strain conditions and the other an axial symmetric configuration. The goal of the first configuration is the assessment of gas pressure evolution in the openings of a repository. The principal input of the problem is the kinetics of gas generation (H 2 generation) given by a step-wise function of time describing the gas generation of one single nuclear waste coli. Then known the repository architecture one could easily calculate the mass of gas generated on one access gallery. Since extreme scenario is studied, we suppose that the gas generated by the set of alveoli is fully located in the access gallery and only a radial gas flux is possible.The hydro mechanical properties of rocks up to the surface were taken into account. For the callovo-Oxfordian clay that constitutes barrier rock in immediate neighbouring of the gallery a model

Long term growth of crop plants on experimental plots created among slag heaps.

Science.gov (United States)

Halecki, Wiktor; Klatka, Sławomir

2018-01-01

Suppression of plant growth is a common problem in post-mining reclaimed areas, as coarse texture of soils may increase nitrate leaching. Assessing feasibility of using solid waste (precipitated solid matter) produced by water and sewage treatment processes in field conditions is very important in mine soil reclamation. Our work investigated the possibility of plant growth in a degraded site covered with sewage-derived sludge material. A test area (21m × 18m) was established on a mine soil heap. Experimental plant species included Camelina sativa, Helianthus annuus, Festuca rubra, Miscanthus giganteus, Amaranthus cruentus, Brassica napus, Melilotus albus, Beta vulgaris, and Zea mays. ANOVA showed sufficient water content and acceptable physical properties of the soil in each year and layer in a multi-year period, indicating that these species were suitable for phytoremediation purposes. Results of trace elements assays indicated low degree of contamination caused by Carbocrash waste material and low potential ecological risk for all plant species. Detrended correspondence analysis revealed that total porosity and capillary porosity were the most important variables for the biosolids among all water content related properties. Overall, crop plants were found useful on heavily degraded land and the soil benefited from their presence. An addition of Carbocrash substrate to mine soil improved the initial stage of soil reclamation and accelerated plant growth. The use of this substrate in phytoremediation helped to balance the content of nutrients, promoted plant growth, and increased plant tolerance to salinity. Sewage sludge-amended biosolids may be applied directly to agricultural soil, not only in experimental conditions. Copyright © 2017 Elsevier Inc. All rights reserved.

Exploration of cystalline rocks for nuclear waste repositories: Some strategies for area characterization

International Nuclear Information System (INIS)

Trask, N.J.; Roseboom, E.H.; Watts, R.D.; Bedinger, M.S.

1991-01-01

A general strategy for the exploration of crystalline rock massed in the eastern United States for the identification of potential sites for high-level radioactive waste repositories has been generated by consideration of the Department of Energy (DOE) Siting Guidelines, available information on these crystalline rocks, and the capabilities and limitations of various exploration methods. The DOE has recently screened over 200 crystalline rock massed in 17 states by means of literature surveys and has recommended 12 rock masses for more intensive investigation including field investigations. The suggested strategy applies to the next stage of screen where the objective is to identify those potential sites that merit detailed site characterization including an exploratory shaft and underground study. This document discusses strategies for reconnaissance and field investigations, including the early phases of drilling, to provide geoscience information on the areas under construction. A complete Area Characterization Plan, to be developed by DOE with involvement of the states within which the areas to be studied are located, will outline all of the investigations to be carried out in the area phase including their cost and scheduling. Here, we provide input for the Area Characterization Plan by discussing what we believe to be the most important issues that need to be addressed in this phase and suggesting methods for their resolution. This report is not intended as a complete outline of area phase geoscience investigations, however. 79 refs., 4 figs

Acoustic remote monitoring of rock and concrete structures for nuclear waste repositories

International Nuclear Information System (INIS)

Young, R.P.

2000-01-01

Excavation and thermally induced damage is of significance for many types of engineering structures but no more so than in the case of nuclear waste repository design. My research and that of my group, formally at Queen's University Canada and Keele University UK and now at the University of Liverpool UK, has focused on the development of acoustic techniques for the in situ detection and quantification of induced damage and fracturing. The application of earthquake seismology to this problem has provided the opportunity to study the micro mechanics of damage mechanisms in situ and provide validation data for predictive geomechanical models used for engineering design. Since 1987 I have been a principal investigator at Atomic Energy of Canada's Underground Research Laboratory (URL), responsible for the development of acoustic emission techniques (AE). In the last twelve years, the application of acoustic techniques to rock damage assessment has been pioneered by my group at the URL and successfully applied in several other major international projects including the ZEDEX, Retrieval and Prototype repository experiments at the Aspo Hard Rock Laboratory (HRL) of SKB Sweden. In this paper I describe what information is available by remote acoustic monitoring of rock and concrete structures and demonstrate this with reference to two international scientific experiments carried out at the URL Canada and the HRL Sweden. (author)

Nuclear fuel waste management program geotechnical studies of Eye-Dashwa Lakes research area rock properties

International Nuclear Information System (INIS)

Chernis, P.J.; Robertson, P.B.

1992-05-01

The Eye-Dashwa Lakes pluton near Atikokan Ontario has been used as a study area for the Canadian nuclear fuel waste management research program. The pluton consists predominately of granite. Fractures formed during cooling of the pluton were filled with a succession of different materials at different times. Measurements of a series of geophysical and geotechnical properties of rock samples are published here in this report, including especially microcrack and pore structures. An indication has been found that a larger proportion of the porosity of Whiteshell and Atikokan samples is contained in connecting pores, compared to other rocks. This may seem surprising in view of the finding that approximately 70% of the effective porosity of Atikokan samples is contained in pockets

Effluents from a waste rock deposit of a former uranium mine in Saxony/Germany - Mass flow balance of water and dissolved solids

International Nuclear Information System (INIS)

Biehler, D.

2002-01-01

Soon after uranium mining had ceased in eastern Germany in 1990, work for remediation of several mining sites began. The Wismut GmbH, owner of the Mine of Dresden-Gittersee's waste rock dump, introduced the concept of reducing the impact to the environment via water and air paths by implementing a multi-layer soil cover. The deposit consists mainly of waste rock (clastic sediments of Doehlener Becken, deep metamorphic rocks) but also of low-grade ore (U-rich coal) and tailing materials. At the time when remediation started, the effluents completely infiltrated the underground. Because of previous surface exfiltration activities, they were already known to be very rich in dissolved solids, especially in sulphate and uranium. As demanded by the state authorities, the owner funded a vast hydrogeological study of the site. In testing the efficiency of surface sealing, the study indicated a mass flow balance of water and dissolved solids for the current situation, and predicted emissions into the water path which would occur after realisation of the proposed soil cover. The field investigation program consisted of: measurements of flow, of concentrations of dissolved solids (esp. U and Ra-226) and of contents of environmental isotopes in precipitation, surface runoff, seepage water and groundwater in the current condition of the dump; the study of waste rock material (geochemistry, mineralogy); waste rock material elution tests; underground investigation by drilling boreholes up to 270 m in depth. The resulting data allowed for: a hydrogeological conceptual model of the site; a consistent mass flow balance for the current condition of the dump; a prediction of concentrations in groundwater resulting after the realisation of a soil cover. The predictions show that the concentrations of dissolved solids in the contaminated groundwater would be significantly decreased. Furthermore it would be possible to reach the standards for drinking water with respect to uranium

Hazardous E-waste and its impact on soil structure

Science.gov (United States)

Dharini, K.; Cynthia, J. Bernadette; Kamalambikai, B.; Sudar Celestina, J. P. Arul; Muthu, D.

2017-07-01

E-waste disposal has been a significant issue over the past few decades with the development of technology and the plethora of electronic products produced. The inclusive term E-Waste encapsulates various forms of electrical and electronical equipment which provides no value to the current owners and it is one among the fastest growing waste streams. E-Waste is a complex, non-biodegradable waste which is generally dumped in mountain like heaps. These wastes are said to have a large quantities of lead, cadmium, arsenic etc.it is mandatory to dispose such scrupulously since they have the ability to affect the soil and water parameters. Solid waste management is a blooming field which strives to reduce the accumulation of used electronic gadgets. Rainwater gets infiltrated through the e-waste landfill and it leaches through the soil which in turn reaches the groundwater directly thereby affecting the water intended for drinking and domestic purposes. This study focuses on the consequences of toxic waste by comparing the difference in properties of the soil structure prior to and after the e-waste landfill at various concentrations.

10 CFR 960.4-2-3 - Rock characteristics.

Science.gov (United States)

2010-01-01

... DEPARTMENT OF ENERGY GENERAL GUIDELINES FOR THE PRELIMINARY SCREENING OF POTENTIAL SITES FOR A NUCLEAR WASTE REPOSITORY Postclosure Guidelines § 960.4-2-3 Rock characteristics. (a) Qualifying condition. The present and... the waste could significantly decrease the isolation provided by the host rock as compared with pre...

Acid-Gangue Interactions in Heap Leach Operations: A Review of the Role of Mineralogy for Predicting Ore Behaviour

Directory of Open Access Journals (Sweden)

Deshenthree Chetty

2018-01-01

Full Text Available Heap leaching accounts for a fifth of global copper production, sourced primarily from porphyry ores, yet metal recoveries are often not optimal. Gangue, and its interaction with acid, plays an important role in such processes. Thus, a proper understanding of gangue minerals present in the ore, their textural relationships relative to particle size distribution, reactivity with acid under different conditions, and relationship to lithotypes and geological alteration in the orebody, is necessary to predict ore behaviour in the comminution, agglomeration, curing and heap leach unit operations. Mineralogical tools available for characterisation are routine X-ray diffraction, optical microscopy, automated scanning electron microscopy, and electron probe microanalysis, accompanied by more recent advancements in hyperspectral infrared imaging and X-ray computed tomography. Integrated use of these techniques allows mineral abundance, textural relationships and mineral chemistry to be addressed over the range of particle and agglomerate sizes. Additionally, diagnostic leach results can be better interpreted when calibrated against robust mineralogical data. The linkage of ore attributes, metallurgical behaviour and their distribution in the orebody forms an integral part of a geometallurgical approach to predicting, and addressing, changes during the heap leaching process. Further investigation should address the fundamentals of gangue reaction with strong acid, and concomitant structural breakdown during curing and agglomeration processes, and how this differs from gangue-acid reactivity under weaker acid conditions, combined with temperature and fluid flow effects of heap leaching. Pre-and post- characterisation is necessary to understand and quantify the effects of variables for gangue-acid reactivity in these various operations. The characterisation outcomes should lead to a refinement of the hierarchy of gangue mineral reactivity under different

Uranium mining and heap leaching in India and related safety measures - A case study of Jajawal mines

International Nuclear Information System (INIS)

Saxena, V.P.; Verma, S.C.

2001-01-01

-project and post-operational data collections both in the project areas and in the surrounding drainage systems are mandatory and overviewed by AERB before clearance. In Jajawal underground mines in Central India, the radiation level is registered at 0.12-0.25 mR/hr and radon daughter working level is measures at 0.005 to 0.015 WL for air. These levels have shown an increase of 15 to 20% during the operations. About 1000 tonnes of low grade ore was heap leached on the surface as technology demonstration project. Measurements of water in pre-heap leaching stage, have indicated concentrations of different nuclides at 0.90 mg/cu.m. (U Nat.), 35 bq/cu.m. (Ra-226), 33 bq/cu.m. (Th-230) and <2 bq/cu.m. (Po-210). Long lived alpha activity in and around heap leaching site has been measured at 0.13 to 0.38 bq/cu.m during the process of operation. Post operational biological uptake of radionuclides, viz. U (natural) : 0.057 mg/kg; Ra-226 : 1.69 Bq/kg; Th-230 : 5.13 Bq/kg and Po-210 : 2.98 Bq/kg, show an increase of 20 to 30% above the pre-operational measurements. The radionuclide related pollution could be contained to manageable limits by current strategy of ventilation of underground mines, disposal by isolation and burial of waste, use of wet scrubbers, adding neutralizing agents to tailing liquids, besides following the principle of ALARA. (author)

Rock mechanics methods and in situ heater tests for design of a nuclear waste repository in basalt

International Nuclear Information System (INIS)

Board, M.P.

1978-01-01

Methods of integrating data from the Near-Surface Test Facility into the overall Waste Isolation Program are examined. Discussions are presented dealing primarily with the application of numerical models to the design of a waste repository. The various types of models currently available are discussed with reference to design in basalt and the breakdown of the problem of repository design is summarized. It is shown that the most efficient method for analyzing repository design is to break the problem down into several problems which are based on physical scale. These include the area directly surrounding a single waste canister (the very near field), the area including many canisters and canister emplacement rooms (the near field), and the area including the entire repository and the rock mass to the free surface (the far field). The methods by which numerical models are used for design are discussed. Flow charts are used to show the basic input data required, the calculational processes used, and the preliminary criteria for judgment of suitable repository performance. It is shown that the ultimate design of the allowable gross thermal loading density, and, thus, the layout of the underground workings is highly dependent upon the rock mass properties supplied as base line input data to the numerical models. Of the many input properties required, the thermal conductivity, the thermal expansion coefficient, and elastic moduli of the rock mass have, perhaps, the greatest effect on the calculation of induced temperatures, stresses, and displacements and, thus, repository design. To ensure that the design continues with confidence, field (in situ) values of input data must be obtained. The role of the Near-Surface Test Facility in situ testing in obtaining these basic required data is discussed

Heat production / host rock compatibility; Waermeentwicklung / Gesteinsvertraeglichkeit

Energy Technology Data Exchange (ETDEWEB)

Meleshyn, A.; Weyand, T.; Bracke, G.; Kull, H.; Wieczorek, K.

2016-05-15

For the final high-level radioactive waste repository potential host rock formations are either rock salt or clays (Kristallin). Heat generating waste (decay heat of the radioactive materials) can be absorbed by the host rock. The effect of temperature increase on the thermal conductivity, the thermal expansion and the mechanical properties of salt, Kristallin, clays and argilliferous geotechnical barriers are described. Further issues of the report are the mineralogical behavior, phase transformations, hydrochemistry, microbial processes, gas formation, thermochemical processes and gas ingress. Recommendations for further research are summarized.

Substrate induced respiration in soils developed under four stages of succession on a colliery heap

Czech Academy of Sciences Publication Activity Database

Szili-Kovács, T.; Elhottová, Dana

2007-01-01

Roč. 35, č. 2 (2007), s. 1169-1172 ISSN 0133-3720 R&D Projects: GA MŠk LC06066 Institutional research plan: CEZ:AV0Z60660521 Keywords : respiration * soils * colliery heap Subject RIV: EH - Ecology, Behaviour Impact factor: 1.190, year: 2007

Effect on localized waste-container failure on radionuclide transport from an underground nuclear waste vault

International Nuclear Information System (INIS)

Cheung, S.C.H.; Chan, T.

1983-07-01

In the geological disposal of nuclear fuel waste, one option is to emplace the waste container in a borehole drilled into the floor of the underground vault. In the borehole, the waste container is surrounded by a compacted soil material known as the buffer. A finite-element simulation has been performed to study the effect of localized partial failure of the waste container on the steady-state radionuclide transport by diffusion from the container through the buffer to the surrounding rock and/or backfill. In this study, the radionuclide concentration at the buffer-backfill interface is assumed to be zero. Two cases are considered at the interface between the buffer and the rock. In case 1, a no-flux boundary condition is used to simulate intact rock. In case 2, a constant radionuclide concentration condition is used to simulate fractured rock with groundwater flow. The results show that the effect of localized partial failure of the waste container on the total flux is dependent on the boundary condition at the buffer-rock interface. For the intact rock condition, the total flux is mainly dependent on the location of the failure. The total flux increases as the location changes from the bottom to the top of the emplaced waste container. For a given localized failure of the waste container, the total flux remains unaffected by the area of failed surface below the top of the failure. For fractured rock, the total flux is directly proportional to the failed surface area of the waste container regardless of the failure location

Natural attenuation in a slag heap contaminated with cadmium: The role of plants and arbuscular mycorrhizal fungi

International Nuclear Information System (INIS)

Gonzalez-Chavez, M.C.; Carrillo-Gonzalez, R.; Gutierrez-Castorena, M.C.

2009-01-01

A field study of the natural attenuation occurring in a slag heap contaminated with high available cadmium was carried out. The aims of this research were: to determine plants colonizing this slag heap; to analyze colonization and morphological biodiversity of spores of arbuscular mycorrhizal fungi (AMF); to determine spore distribution in undisturbed samples; to know mycelium and glomalin abundance in the rhizosphere of these plants, and to investigate glomalin participation in Cd-stabilization. Forming vegetal islands, 22 different pioneering plant species from 11 families were colonizing the slag heap. The most common plants were species of Fabaceae, Asteraceae and Poaceae. Almost all plants were hosting AMF in their roots, and spores belonging to Gigaspora, Glomus, Scutellospora and Acaulospora species were observed. Micromorphological analysis showed that spores were related to decomposing vegetal residues and excrements, which means that mesofauna is contributing to their dispersion in the groundmass. Mycelium mass ranged from 0.11 to 26.3 mg/g, which contained between 13 and 75 mg of glomalin/g. Slag-extracted total glomalin was between 0.36 and 4.74 mg/g. Cadmium sequestered by glomalin extracted from either slag or mycelium was 0.028 mg/g. The ecological implication of these results is that organisms occupying vegetal patches are modifying mine residues, which contribute to soil formation

Natural attenuation in a slag heap contaminated with cadmium: The role of plants and arbuscular mycorrhizal fungi

Energy Technology Data Exchange (ETDEWEB)

Gonzalez-Chavez, M.C. [Programa de Edafologia. Colegio de Postgraduados en Ciencias Agricolas, Campus Montecillo. Carretera Mexico-Texcoco, km 36.5. Montecillo, Texcoco, Mexico, 56230 (Mexico)], E-mail: carmeng@colpos.mx; Carrillo-Gonzalez, R.; Gutierrez-Castorena, M.C. [Programa de Edafologia. Colegio de Postgraduados en Ciencias Agricolas, Campus Montecillo. Carretera Mexico-Texcoco, km 36.5. Montecillo, Texcoco, Mexico, 56230 (Mexico)

2009-01-30

A field study of the natural attenuation occurring in a slag heap contaminated with high available cadmium was carried out. The aims of this research were: to determine plants colonizing this slag heap; to analyze colonization and morphological biodiversity of spores of arbuscular mycorrhizal fungi (AMF); to determine spore distribution in undisturbed samples; to know mycelium and glomalin abundance in the rhizosphere of these plants, and to investigate glomalin participation in Cd-stabilization. Forming vegetal islands, 22 different pioneering plant species from 11 families were colonizing the slag heap. The most common plants were species of Fabaceae, Asteraceae and Poaceae. Almost all plants were hosting AMF in their roots, and spores belonging to Gigaspora, Glomus, Scutellospora and Acaulospora species were observed. Micromorphological analysis showed that spores were related to decomposing vegetal residues and excrements, which means that mesofauna is contributing to their dispersion in the groundmass. Mycelium mass ranged from 0.11 to 26.3 mg/g, which contained between 13 and 75 mg of glomalin/g. Slag-extracted total glomalin was between 0.36 and 4.74 mg/g. Cadmium sequestered by glomalin extracted from either slag or mycelium was 0.028 mg/g. The ecological implication of these results is that organisms occupying vegetal patches are modifying mine residues, which contribute to soil formation.

Application of Ga-Al discrimination plots in identification of high strength granitic host rocks for deep geological repository of high level radioactive waste

International Nuclear Information System (INIS)

Bajpai, R.K.; Narayan, P.K.; Trivedi, R.K.; Purohit, M.K.

2010-01-01

The permanent disposal of vitrified high level wastes and in some cases even spent fuel, is being planned in specifically designed and built deep geological repository located in the depth range of 500-600m in appropriate host rock at carefully selected sites. Such facilities are expected to provide very long term isolation and confinement to the disposed waste by means of long term mechanical stability of such structures that results from very high strength and homogeneity of the chosen rock, geochemical compatible environment around the disposed waste and general lack of groundwater. In Indian geological repository development programme, granites have been selected as target host rock and large scale characterization studies have been undertaken to develop database of mineralogy, petrology, geochemistry and rock mechanical characteristics. The paper proposes a new approach for demarcation of high strength homogeneous granite rocks from within an area of about 100 square kilometres wherein a cocktail of granites of different origins with varying rock mass characteristics co exists. The study area is characterised by the presence of A, S and I type granites toughly intermixed. The S type granites are derived from sedimentary parent material and therefore carry relics of parent fabric and at times undigested material with resultant reduction in their strength and increased inhomogeneity. On the other hand I type varieties are derived from igneous parents and are more homogeneous with sufficient strength. The A type granites are emplaced as molten mass in a complete non-tectonic setting with resultant homogeneous compositions, absence of tectonic fabric and very high strength. Besides they are silica rich with less vulnerability to alterations with time. Thus A type granites are most suited for construction of Deep Geological Repository. For developing a geochemical approach for establishing relation between chemical compositions and rock strength parameters, a

Heap-leaching of low-grade uranium ore at SOMAIR: from laboratory tests to production of 700 tonnes U per year

Energy Technology Data Exchange (ETDEWEB)

Durupt, N.; Blanvillain, J.J., E-mail: nicolas.durupt@areva.com [AREVA NC, Service d' Etudes de Procedes et d' Analyses (SEPA), Bessines sur Gartempe (France)

2010-07-01

In 2006, SOMAIR decided to increase the uranium production by 50% using heap leaching for the treatment of low grade ores. These ores, which come from different ores with various properties, have been studied in four steps: Lab tests: to compare the ores (characterization, acid consumptions, recovery); Column tests on an average sample: to define significant parameters for a feasibility study; Column tests on specific samples: to optimize recovery for each ore and identify problems of percolation due to the clays; and, Pilot tests in large boxes (stalls): to validate process parameters. Uranium production by heap leaching started commercially in July 2009. (author)

Use of low-cost heat sources to improve the efficiency of heap leaching of uranium ores. Part of a coordinated programme on bacterial leaching of uranium ores

International Nuclear Information System (INIS)

Ajuria, S.

1977-12-01

Basic technical parameters are given of two solar heaters designed for use in heap leaching of uranium ores. Inexpensive and easily available materials such as flat glass panes, glass tubing and corrugated metal sheets were used in the construction of the heaters. Under optimum conditions, the heaters can produce temperature differentials of 52 0 C (50 0 C) at the flow rate of 30ml/min. The dependence of percent recovery on the temperature of solutions in heap leaching of ore from 'El Nopal' was studied. Even though no precise correlation was found, an increase in the temperature of solutions seems to improve the efficiency of heap leaching

Rock salt as a medium for long-term isolation of radioactive wastes - a reassessment

International Nuclear Information System (INIS)

Chaturvedi, L.

1985-01-01

Rock salt has been regarded as a suitable medium for the permanent disposal of high and medium level radioactive wastes since the National Academy of Sciences recommended it in 1957. As a result of detained site-specific studies conducted for the Waste Isolation Pilot Plant (WIPP) project in New Mexico, however, several potential problems which are unique to bedded salt deposits have emerged. These include 1) the need to delineate the extent and rate of past dissolution and projections for the future, 2) the origin and significance of brines often found underlying the salt beds, 3) the rate and volume of migration of brine from the salt crystals towards the heat producing waste canisters, 4) the creep rates and implications for retrievability, and 5) the existence of potash and oil and gas resources with implications of human intrusion in the future. These questions will also be faced for sites in salt domes with added complications due to more complex structure and hydrology. The experience at WIPP shows that the site characterization process for high level waste repositories in bedded or dome salt should aim at identifying the important issues of site suitability early in the process and a clear program should be established to address these issues

Hydrological and geochemical investigation on the volcanic rock and gneissic rock area

Energy Technology Data Exchange (ETDEWEB)

Koh, Yong Kwon; Jeong, Chan Ho; Ryu, Kun Seok; Kim, Byoung Yeop; Park, Hyung Kun; Yu, Sang Woo; Jang, Hyu Kun; Lee, Suk Chi; Choi, Ki Young; Jeon, Hyu Woong; Kim, Do Hyoung [Daejong University, Daejeon (Korea, Republic of)

2010-01-15

The purpose of this study is to supply the basic data and optimum study site among volcanic rock area and gneissic rock area for high-level radioactive waste disposal. For this purpose, geological, hydrogeological and geochemical data from previously published literatures were collected and analyzed. In this study, we selected 36 volcanic rock sites and 26 gneissic sites as the candidate sites for high level radwaste disposal. Finally, for four sites(M-1, M-13, V-1 and V-13 sites) were selected as the study sites. The geochemical characteristics of groundwaters of each study site were statistically analyzed. The nitrate contamination and the sea water mixing will be important factors on the assessment of behaviour of radionuclides under groundwater environment. From the deep geothermal study, alkaline and sodium-bicarbonate chemical environment, and sea water mixing should be considered as the key factors for the deep disposal of high-level radioactive waste

Reclamation of soils influenced by coal mining in Southern European Russia

Science.gov (United States)

Alekseenko, Vladimir; Bech, Jaume; Alekseenko, Alexey; Shvydkaya, Natalya; Roca, Núria

2016-04-01

In the recent decades, the concentrations of metals have increased in such media of biosphere as atmosphere, hydrosphere, pedosphere. The greatest geochemical changes have occurred in soils, which are the deposing medium where the high concentrations of metals are saved for years after their direct human use. Mining sites and beneficiation zones are the areas of the highest concentrations of metals in soils. Coal mining areas in the European part of Russia (Rostov region) were selected for a detailed consideration. Soil samples were taken from the uppermost soil horizons: layer of 0-30 cm. The soil samples were analysed for gross concentrations of Cu, Zn, Pb, Ag, Sn, Mo, Ba, Co, Ni, Mn, Ti, V, Cr, Ga, P, Li, Sr, Y, Yb, Nb, Sc, and Zr, using emission spectral analysis. All ordinary analyses were carried out in the certified and accredited laboratory. The external control was conducted by the X-ray fluorescence, gravimetric, and neutron activation analyses. Calculation of random and systematic errors showed high analyses repeatability and correctness. Several cases of self-purification of soils and restoration of landscapes were discussed. The way of remediation through the flooding of mining sites with water was investigated as well as filling of natural relief depressions with soils and dumps. The process of Technosols remediation at the sites occupied by tailings of waste heaps was considered separately. In conclusion: 1. The dominant contemporary way of remediation in Southern European Russia does not prevent the spread of metals through the decades. The modern underground coal mining leads to the destruction of soils in the area directly occupied by wastes and by rock dumps located nearby. 2. Soils have not formed yet as a result of self-restoration at the waste heaps at the age of 50 years, spontaneously combusted decades ago. The vegetation formed during this time virtually eliminates the occurrence of any significant soil-forming process. The ponds formed by

Acid mine drainage: mining and water pollution issues in British Columbia

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-12-31

The importance of protecting water quality and some of the problems associated with mineral development are described. Negative impacts of mining operations such as sedimentation, water disturbances, and water pollution from waste rock and tailings are considered. Mining wastes, types of water pollution from mining, the legacy of acid mine drainage, predicting acid mine drainage, preventing and mitigating acid mine drainage, examples from the past, and cyanide heap-leaching are discussed. The real costs of mining at the Telkwa open pit coal mine are assessed. British Columbia mines that are known for or are potentially acid generating are shown on a map. 32 refs., 10 figs.

Actinorhizal Alder Phytostabilization Alters Microbial Community Dynamics in Gold Mine Waste Rock from Northern Quebec: A Greenhouse Study.

Directory of Open Access Journals (Sweden)

Katrina L Callender

Full Text Available Phytotechnologies are rapidly replacing conventional ex-situ remediation techniques as they have the added benefit of restoring aesthetic value, important in the reclamation of mine sites. Alders are pioneer species that can tolerate and proliferate in nutrient-poor, contaminated environments, largely due to symbiotic root associations with the N2-fixing bacteria, Frankia and ectomycorrhizal (ECM fungi. In this study, we investigated the growth of two Frankia-inoculated (actinorhizal alder species, A. crispa and A. glutinosa, in gold mine waste rock from northern Quebec. Alder species had similar survival rates and positively impacted soil quality and physico-chemical properties in similar ways, restoring soil pH to neutrality and reducing extractable metals up to two-fold, while not hyperaccumulating them into above-ground plant biomass. A. glutinosa outperformed A. crispa in terms of growth, as estimated by the seedling volume index (SVI, and root length. Pyrosequencing of the bacterial 16S rRNA gene for bacteria and the ribosomal internal transcribed spacer (ITS region for fungi provided a comprehensive, direct characterization of microbial communities in gold mine waste rock and fine tailings. Plant- and treatment-specific shifts in soil microbial community compositions were observed in planted mine residues. Shannon diversity and the abundance of microbes involved in key ecosystem processes such as contaminant degradation (Sphingomonas, Sphingobium and Pseudomonas, metal sequestration (Brevundimonas and Caulobacter and N2-fixation (Azotobacter, Mesorhizobium, Rhizobium and Pseudomonas increased over time, i.e., as plants established in mine waste rock. Acetate mineralization and most probable number (MPN assays showed that revegetation positively stimulated both bulk and rhizosphere communities, increasing microbial density (biomass increase of 2 orders of magnitude and mineralization (five-fold. Genomic techniques proved useful in

Application of Response Surface Methodology on Leaching of Iron from Partially Laterised Khondalite Rocks: A Bauxite Mining Waste

Science.gov (United States)

Swain, Ranjita; Bhima Rao, R.

2018-04-01

In the present investigation, response surface methodology (RSM) is used for a quadratic model that continuously controls the process parameters. This model is used to optimize the removal of iron oxide from Partially Laterised Khondalite (PLK) rocks which is influenced by several independent variables namely acid concentration, time and temperature. Second order response functions are produced for leaching of iron oxide from PLK rocks-a bauxite mining waste. In RSM, Box-Behnken design is used for the process optimization to achieve maximum removal of iron oxide. The influence of the process variables of leaching of iron oxide is presented in the form of 3-D response graphs. The results of this investigation reveals that 3 M hydrochloric acid concentration, 240 min time and 373 K temperature are found to be the best conditions for removal of 99% Fe2O3. The product obtain at this condition contain 80% brightness which is suitable for ceramic and filler industry applications. The novelity of the work is that the waste can be a value added product after suitable physical beneficiation and chemical treatment.

Application of Response Surface Methodology on Leaching of Iron from Partially Laterised Khondalite Rocks: A Bauxite Mining Waste

Science.gov (United States)

Swain, Ranjita; Bhima Rao, R.

2017-08-01

In the present investigation, response surface methodology (RSM) is used for a quadratic model that continuously controls the process parameters. This model is used to optimize the removal of iron oxide from Partially Laterised Khondalite (PLK) rocks which is influenced by several independent variables namely acid concentration, time and temperature. Second order response functions are produced for leaching of iron oxide from PLK rocks-a bauxite mining waste. In RSM, Box-Behnken design is used for the process optimization to achieve maximum removal of iron oxide. The influence of the process variables of leaching of iron oxide is presented in the form of 3-D response graphs. The results of this investigation reveals that 3 M hydrochloric acid concentration, 240 min time and 373 K temperature are found to be the best conditions for removal of 99% Fe2O3. The product obtain at this condition contain 80% brightness which is suitable for ceramic and filler industry applications. The novelity of the work is that the waste can be a value added product after suitable physical beneficiation and chemical treatment.

Transferability of geodata from European to Canadian (Ontario) sedimentary rocks to study gas transport from nuclear wastes repositories

International Nuclear Information System (INIS)

Fall, M.; Ghafari, H.; Evgin, E.; Nguyen, T.S.

2010-01-01

Document available in extended abstract form only. A deep geological repository (DGR) for low and intermediate level waste in southern Ontario is currently proposed, at a depth of approximately 680 m in an argillaceous limestone formation (Cobourg Limestone) overlain by 200 m of low permeability shale (Ordovician Shale). Significant quantities of gas could be generated in the aforementioned DGR from several processes (e.g., degradation of waste forms, corrosion of waste containers). The accumulation and release of such gases from the repository system may affect a number of processes that influence its long-term safety. Consequently, safety assessments of the proposed DGR need to be supported by a solid understanding of the main mechanisms associated with gas generation and migration and the capability to mathematically model those mechanisms. The development of those mathematical models would usually require the consideration of complex coupled thermo-hydro-mechanical- chemical (THMC) processes. A research program is being conducted in the Department of Civil Engineering of the University of Ottawa in collaboration with the Canadian Nuclear Safety Commission (CNSC) to model the coupled THMC processes associated with gas migration and their impacts on the safety of DGR in southern Ontario. The development and validation of such model as well as the assessment of the impact of gas migration need the acquisition of sufficient amount of (good quality) data on the geomechanical, geochemical, hydraulic, thermal properties of the sedimentary rocks in Southern Ontario as well as relevant gas transport parameters, such as gas entry pressure, Klinkenberg effect, intrinsic permeability, capillary pressure-water saturation relationship. During the past fifteen years, several laboratory and field investigations have been conducted in several countries to acquire geo-data to study and model the THMC processes associated with gas migration in DGR in sedimentary rocks. However

Potential host media for a high-level waste repository

Energy Technology Data Exchange (ETDEWEB)

Hustrulid, W

1982-01-01

Earlier studies of burial of radioactive wastes in geologic repositories had concentrated on salt formations for well-publicized reasons. However, under the Carter administration, significant changes were made in the US nuclear waste management program. Changes which were made were: (1) expansion of the number of rock types under consideration; (2) adoption of the multiple-barrier approach to waste containment; (3) additional requirements for waste retrieval; and (4) new criteria proposed by the Nuclear Regulatory Commission for the isolation of high-level waste in geologic repositories. Results of the studies of different types of rocks as repository sites are summarized herein. It is concluded that each generic rock type has certain advantages and disadvantages when considered from various aspects of the waste disposal problem and that characteristics of rocks are so varied that a most favorable or least favorable rock type cannot be easily identified. This lack of definitive characteristics of rocks makes site selection and good engineering barriers very important for containment of the wastes. (BLM)

Studies on feasibility of recovering uranium from Dongkeng second class submarginal ore by heap leaching

International Nuclear Information System (INIS)

Yang Qingyi

1994-01-01

It was proved that it is feasible in economy and in technology to recover uranium from Dongkeng second class submarginal ore by heap leaching, on the basis of analysing the conditions of Mine No. 743 and the tests conducted. Moreover, the social and environmental effects are good. Two valuable suggestions are presented

Radioactive waste repositories in hard rock aquifers--hydrodynamic aspects

International Nuclear Information System (INIS)

Thunvik, R.; Braester, C.

1984-01-01

A mathematical model for mass and heat flow and a computer program have been developed to demonstrate the effect of heat released from a hypothetical radioactive waste repository on the groundwater flow regime. The model, based on the continuum approach, conceptualizes the fracture pattern and the solid blocks as two overlapping continua and consists of a set of coupled nonlinear partial differential equations. The general form of the model is three-dimensional and can treat the fluid and rock either as two separate media with a quasi-steady exchange of heat between them or as a single equivalent medium with instantaneous thermal equilibrium. Numerical solutions have been obtained by the Galerkin finite element method. Examples have been presented for topographically different locations of the repository: below a horizontal ground surface, below a hill crest, below a hillside, and close to major fractures. The effects of constant permeability and porosity or downward decreasing with depth as well as the effect of anisotropic permeability have been investigated. Solutions include the velocity field, path lines, and traveling times of water particles passing the repository and the temperature distribution. The examples have been worked out for a two-dimensional flow domain, assuming that instantaneous thermal equilibrium takes place. This assumption was found to be justified by the relatively low flow velocities that occurred in the examples. Except for the location close to a major draining fracture, heat released from the radioactive waste repository may have a significant influence on the flow regime around the repository

Analysis of hydraulic gradients across the host rock at the proposed Texas Panhandle nuclear-waste repository site

International Nuclear Information System (INIS)

Bair, E.S.

1987-01-01

Analysis of the direction of ground-water flow across the host rock at the proposed high-level nuclear-waste repository site in Deaf Smith County, Texas, is complicated by vertical and lateral changes in the density of formation fluids in the various hydrogeologic units that overlie and underlie the proposed host rock. Because the concept of hydraulic head is not valid when evaluating vertical hydraulic gradients in a variably-density flow system, other methods were used to determine the direction and magnitude of vertical hydraulic gradients at the proposed site where the specific gravity of formation fluids varies between 1.00 and 1.28. The direction of ground-water flow across the proposed host rock, an 80-foot-thick salt bed in the Lower San Andres Formation, was determined by calculating vertical hydraulic gradients based on formation pressure and fluid density data, and by analysis of pressure-depth diagrams. Based on data from the vicinity of the proposed site, both methods indicate the potential for downflow across the host rock. Downflow or predominantly horizontal flow is considered a favorable prewaste emplacement condition because it prolongs the travel time to the biosphere of any naturally or accidentally released radionuclides

Radiant energy dissipation during final storage of high-level radioactive waste in rock salt

International Nuclear Information System (INIS)

Ramthun, H.

1981-08-01

A final disposal concept is assumed where the high-active waste from 1400 t of uranium, remaining after conditioning, is solidified in borosilicate glass and distributed in 1.760 waste casks. These containers 1.2 m in height and 0.3 m in diameter are to be buried 10 years after the fuel is removed from the reactor in the 300 m deep boreholes of a salt dome. For this design the mean absorbed dose rates are calculated in the glass die (3.9 Gy/s), the steel mantle (0.26 Gy/s) and in the salt rock (0.12 Gy/s at a distance of 1 cm and 0.034 Gy/s at a distance of 9 cm from the container surface) valid at the beginning of disposal. The risk involved with these amounts of stored lattice energy is shortly discussed. (orig.) [de

Current scenario of chalcopyrite bioleaching: a review on the recent advances to its heap-leach technology.

Science.gov (United States)

Panda, Sandeep; Akcil, Ata; Pradhan, Nilotpala; Deveci, Haci

2015-11-01

Chalcopyrite is the primary copper mineral used for production of copper metal. Today, as a result of rapid industrialization, there has been enormous demand to profitably process the low grade chalcopyrite and "dirty" concentrates through bioleaching. In the current scenario, heap bioleaching is the most advanced and preferred eco-friendly technology for processing of low grade, uneconomic/difficult-to-enrich ores for copper extraction. This paper reviews the current status of chalcopyrite bioleaching. Advanced information with the attempts made for understanding the diversity of bioleaching microorganisms; role of OMICs based research for future applications to industrial sectors and chemical/microbial aspects of chalcopyrite bioleaching is discussed. Additionally, the current progress made to overcome the problems of passivation as seen in chalcopyrite bioleaching systems have been conversed. Furthermore, advances in the designing of heap bioleaching plant along with microbial and environmental factors of importance have been reviewed with conclusions into the future prospects of chalcopyrite bioleaching. Copyright © 2015 Elsevier Ltd. All rights reserved.

Lithology, microstructures, fluid inclusions, and geochemistry of rock salt and of the cap-rock contact in Oakwood Dome, East Texas: significance for nuclear waste storage. Report of investigations No. 120

International Nuclear Information System (INIS)

Dix, O.R.; Jackson, M.P.A.

1982-01-01

Oakwood salt dome in Leon and Freestone Counties, Texas, has a core composed of a diapiric salt stock at a depth of 355 m. A vertical borehole in the center of the salt stock yielded 57.3 m of continuous rock-salt core overlain by 137 m of anhydrite-calcite cap rock. The lower 55.3 m of rock salt exhibits a strong, penetrative schistosity and parallel cleavage dipping at 30 to 40 0 and more than 60 variably dipping layers of disseminated anhydrite. Anhydrite constitutes 1.3 +- 0.7 percent of the rock-salt core. The upper 2 m of rock salt is unfoliated, comprising a lower 1.4-m interval of medium-grained granoblastic rock salt and an upper 0.6-m interval of coarse-grained granoblastic rock salt. An abrupt, cavity-free contact separates rock salt from laminated cap rock consisting of granoblastic-polygonal anhydrite virtually devoid of halite or pore space. Microstructures and concentration gradients of fluid inclusions suggest that the unfoliated rock salt at the crest of the salt stock was once strongly foliated, but that this fabric was destroyed by solid-state recrystallization. Downward movement of brine from the rock-salt - cap-rock contact was apparently accompanied by two recrystallization fronts. Dissolution of halite at the contact released disseminated anhydrite that presumably accumulated as sand on the floor of the dissolution cavity. Renewed rise of the salt stock closed the cavity, and the anhydrite sand was accreted against the base of the cap rock. Much, if not all, of the lamination in the 80 m of anhydrite cap rock may result from cycles of dissolution, recrystallization, and upward movement in the salt stock, followed by accretion of anhydrite residuum as laminae against the base of the cap rock. These processes, which are strongly influenced by fluids, act both to breach waste repositories and to geologically isolate them

Sustainable wood waste management in Nigeria

Directory of Open Access Journals (Sweden)

Owoyemi Jacob Mayowa

2016-09-01

Full Text Available Wood industries produce large volumes of residues which must be utilized, marketed or properly disposed of. Heaps of wood residues are common features in wood industries throughout the year. In Nigeria, this residue is generally regarded as waste and this has led to open burning practices, dumping in water bodies or dumping in an open area which constitutes environmental pollution. Sawmills in Nigeria generated over 1,000,000 m3 of wood waste in 2010 while about 5000 m3 of waste was generated in plywood mills. Nigeria generates about 1.8 million tons of sawdust annually and 5.2 million tons of wood wastes. The impact of improper disposal of waste wood on the environment affects both the aquatic and terrestrial ecosystems. Also burning of waste wood releases greenhouse gases into the atmosphere causing various health issues. Reuse/recycling of these wood residues in Nigeria will reduce the pressure on our ever decreasing forests, reduce environmental pollution, create wealth and employment. The literature available on this subject was reviewed and this article, therefore, focuses on the various methods of wood waste disposal and its utilization in Nigerian wood industries, the effects of wood waste on the environment as well as on human health and the benefits of proper wood waste management practices.

Transient response in granular quasi-two-dimensional bounded heap flow.

Science.gov (United States)

Xiao, Hongyi; Ottino, Julio M; Lueptow, Richard M; Umbanhowar, Paul B

2017-10-01

We study the transition between steady flows of noncohesive granular materials in quasi-two-dimensional bounded heaps by suddenly changing the feed rate. In both experiments and simulations, the primary feature of the transition is a wedge of flowing particles that propagates downstream over the rising free surface with a wedge front velocity inversely proportional to the square root of time. An additional longer duration transient process continues after the wedge front reaches the downstream wall. The entire transition is well modeled as a moving boundary problem with a diffusionlike equation derived from local mass balance and a local relation between the flux and the surface slope.

Characterizing fractured plutonic rocks of the Canadian shield for deep geological disposal of Canada's radioactive wastes

International Nuclear Information System (INIS)

Lodha, G.S.; Davison, C.C.; Gascoyne, M.

1998-01-01

Since 1978 AECL has been investigating plutonic rocks of the Canadian Shield as a potential medium for the disposal of Canada's nuclear fuel waste. During the last two years this study has been continued as part of Ontario Hydro's used fuel disposal program. Methods have been developed for characterizing the geotechnical conditions at the regional scale of the Canadian Shield as well as for characterizing conditions at the site scale and the very near-field scale needed for locating and designing disposal vault rooms and waste emplacement areas. The Whiteshell Research Area (WRA) and the Underground Research Laboratory (URL) in southeastern Manitoba have been extensively used to develop and demonstrate the different scales of characterization methods. At the regional scale, airborne magnetic and electromagnetic surveys combined with LANDSAT 5 and surface gravity survey data have been helpful in identifying boundaries of the plutonic rocks , overburden thicknesses, major lineaments that might be geological structures, lithological contacts and depths of the batholiths. Surface geological mapping of exposed rock outcrops, combined with surface VLF/EM, radar and seismic reflection surveys were useful in identifying the orientation and depth continuity of low-dipping fracture zones beneath rock outcrops to a depth of 500 to 1000 m. The surface time-domain EM method has provided encouraging results for identifying the depth of highly saline pore waters. The regional site scale investigations at the WRA included the drilling of twenty deep boreholes (> 500 m) at seven separate study areas. Geological core logging combined with borehole geophysical logging, TV/ATV logging, flowmeter logging and full waveform sonic logging in these boreholes helped to confirm the location of hydro geologically important fractures, orient cores and infer the relative permeability of some fracture zones. Single-hole radar and crosshole seismic tomography surveys were useful to establish the

An integrated approach to isotopic study of crystalline rock for a high-level waste repository: Area phase

International Nuclear Information System (INIS)

Gilbert, L.A.

1986-01-01

An integrated approach to assessing isotopic systems in crystalline rock is planned for area phase studies. This approach combines radiogenic isotope systems with petrography in order to characterize potential crystalline repository media. The coeval use of selected isotope systems will minimize the limitations of each method and provide intensive parameters yielding data on alteration timing, secondary mineral formation, temperature history, and radionuclide species migration. Isotope systems will be selected in order to measure differences in sensitivity to thermal disturbances and mobility due to fluid interaction. Comparative evaluation of isotope pair behavior may be used in combination with mineral versus whole-rock dates to provide data on heating and mobilization of alkali elements, lanthanides, and gases, caused by future introduction of waste

Recultivation of mining waste dumps in the Ruhr area, Germany

International Nuclear Information System (INIS)

Schulz, D.

1996-01-01

In 1993 Ruhrkohle AG produced 41.9 million tons of coal and 19.1 million m 3 of mining waste. Of this, 0.7 million m 3 were used underground as stowing material, 4.7 million m 3 was used commercially, while the remaining 13.7 million m 3 required dumping. Efforts related to the use and disposal of the material up to now dumped are concentrating on applying technical methods to reduce the production of waste underground, on opening up new markets of this material, on utilization of mining waste as a building material, and on low-environmental-impact dumping. Since the late 1970s, the mining waste heaps in the Ruhr mining region have been conceived and designed as landscape structures, i.e. they are integrated into the landscape by means of careful planning and design, and are immediately planted with vegetation. 9 refs., 5 figs

Development of waste packages for tuff

International Nuclear Information System (INIS)

Rothman, A.J.

1982-01-01

The objective of this program is to develop nuclear waste packages that meet the Nuclear Regulatory Commission's requirements for a licensed repository in tuff at the Nevada Test Site. Selected accomplishments for FY82 are: (1) Selection, collection of rock, and characterization of suitable outcrops (for lab experiments); (2) Rock-water interactions (Bullfrog Tuff); (3) Corrosion tests of ferrous metals; (4) Thermal modeling of waste package in host rock; (5) Preliminary fabrication tests of alternate backfills (crushed tuff); (6) Reviewed Westinghouse conceptual waste package designs for tuff and began modification for unsaturated zone; and (7) Waste Package Codes (BARIER and WAPPA) now running on our computer. Brief discussions are presented for rock-water interactions, corrosion tests of ferrous metals, and thermal and radionuclide migration modelling

A structural behavior study of rock caverns considering the effects of discontinuities

International Nuclear Information System (INIS)

Kim, Jhin Wung; Kim, Sun Hoon; Seo, Jeong Moon; Choi, Kyu Seop; Kim, Dae Hong; Lee, Kyung Jin; Choi, In Gil; Lee, Dong Yong

1990-06-01

The objective of this study is to understand the effects of discontinuities within rock masses on the structural behavior of underground rock caverns for radioactive waste disposal, and then develop a computer program for the structural analysis of rock caverns considering these effect of discontinuities. The behavior of rock masses, such as strength, deformation modes, ect., is very difficult to predict because discontinuities in the form of microcracks or joints are randomly distributed within rock masses. Discontinuties existing around the rock cavern for underground radioactive waste disposal may become the main transport pathways of radionuclides, and reduce the strength of rock masses eventually causing the rock cavern structure unstable. Therefore, a comprehensive understanding of the mechanical properties and behavior of discontinuous rock masses and an improvement of structural analysis methods are essential in order to understand the behavior of underground rock cavern structures properly in order to design safe and economic understanding the behavior of discontinuous rock masses is essential. Therfore, this study includes literature review on mechanical properties of and computational models for discontinuous rock masses, and on structures. Then, bases on the engineering judgement a suitable selection and slight modifications on computational models and analysis methods have been made before developing the structural analysis computer program for underground radioactive waste disposal structures. (author)

Diffusive transport and reaction in clay rocks: A storage (nuclear waste, CO2, H2), energy (shale gas) and water quality issue

Science.gov (United States)

Charlet, Laurent; Alt-Epping, Peter; Wersin, Paul; Gilbert, Benjamin

2017-08-01

Clay rocks are low permeability sedimentary formations that provide records of Earth history, influence the quality of water resources, and that are increasingly used for the extraction or storage of energy resources and the sequestration of waste materials. Informed use of clay rock formations to achieve low-carbon or carbon-free energy goals requires the ability to predict the rates of diffusive transport processes for chemically diverse dissolved and gaseous species over periods up to thousands of years. We survey the composition, properties and uses of clay rock and summarize fundamental science challenges in developing confident conceptual and quantitative gas and solute transport models.

Colonization of colliery spoil heaps by millipedes (Diplopoda) and terrestrial isopods (Oniscidea) in the Sokolov region, Czech Republic

Czech Academy of Sciences Publication Activity Database

Tajovský, Karel

2001-01-01

Roč. 9, č. 4 (2001), s. 365-369 ISSN 1061-2971 Institutional research plan: CEZ:AV0Z6066911 Keywords : colliery spoil heaps * succession * rekultivation Subject RIV: EH - Ecology, Behaviour Impact factor: 1.011, year: 2001

Environmental remediation of the Wismut legacy and utilization of the reclaimed areas, waste rock piles and tailings ponds

International Nuclear Information System (INIS)

Hagen, M.; Jakubick, A.T.

2006-01-01

Between 1945 and reunification (1989) of Germany more than 232 000 t of U 3 O 8 has been produced in Saxony and Thuringia, East Germany. This affected an area of approximately 100 km 2 and left behind an extensive legacy of contaminated operations areas, underground and open pit mines, waste rock piles and tailings ponds. Following reunification, DM 13 billion (Euro 6.6 billion) were committed (and later revised to Euro 6.2 billion) to remediation of the liabilities and the government owned corporation, Wismut GmbH entrusted with the implementation of the Environmental Remediation (ER) of the liabilities. The prime goal of the ER Project follows from the legal requirements to abate health risks, mitigate existing and prevent future environmental damages. During the investigations and assessment of risks, development of remediation concepts, adoption of suitable technologies and work procedures as well as physical implementation of the remedial measures extensive use was made of international (mostly US and Canadian) ER experience. The extent of remedial measures was based on object-specific Environmental Assessments rather than on uniformly applied health/environmental standards. The ER workflow is more an iterative process than a linear succession of tasks, such as common for civil engineering projects. The internal (technical) parts of the problems were partly resolved by using Conceptual Site Models (CSM) for selection and prioritization of remedial measures. Reclamation of the waste rock piles is by covering in situ, relocation to a central pile or backfilling into an open pit. The backfilling of the open pit at Ronneburg with acid generating waste rock has been optimized from a geochemical point of view. For tailings ponds reclamation in form of dry landforms is being followed. To increase release (and reuse) of scrap metal from demolition, a fast and reliable method of discrimination of the non-contaminated metal has been developed. The flooding of

Emissions of ammonia, nitrous oxide and methane during composting of organic household waste

International Nuclear Information System (INIS)

Gunnarsdotter Beck-Friis, Barbro

2001-01-01

In Sweden, composting of source-separated organic household waste is increasing, both domestically at the small-scale, and in larger municipal plants. Composting means a microbial decomposition of organic material, which results in the production of environmentally undesirable gases, such as ammonia (NH 3 ), nitrous oxide (N 2 O) and methane (CH 4 ). The aim of this thesis was to study the emissions of NH 3 , N 2 O and CH 4 to the atmosphere during composting of source-separated organic household waste. The studies were conducted in an experimental reactor under constant and controlled conditions and in municipal compost heaps. Emissions of NH 3 , N 2 O and CH 4 occurred at different phases during composting. Ammonia started to volatilise during the shift from mesophilic to thermophilic conditions when short-chained fatty acids were decomposed. Nitrous oxide was only emitted during the first days of composting and later during the cooling phase when nitrate was formed. Methane was only produced during the thermophilic phase. Large municipal compost heaps are a significant source for the production and emission of the greenhouse gases N 2 O and CH 4 . To avoid unwanted gaseous emissions to the atmosphere during composting, gaseous exchange with the atmosphere should be controlled in future composting plants

Mine Waste Disposal and Managements

Energy Technology Data Exchange (ETDEWEB)

Cheong, Young-Wook; Min, Jeong-Sik; Kwon, Kwang-Soo [Korea Institute of Geology Mining and Materials, Taejon (KR)] (and others)

1999-12-01

This research project deals with: Analysis and characterization of mine waste piles or tailings impoundment abandoned in mining areas; Survey of mining environmental pollution from mine waste impounds; Modelling of pollutants in groundwater around tailings impoundment; Demonstration of acid rock drainage from coal mine waste rock piles and experiment of seeding on waste rock surface; Development of a liner using tailings. Most of mine wastes are deposited on natural ground without artificial liners and capping for preventing contamination of groundwater around mine waste piles or containments. In case of some mine waste piles or containments, pollutants have been released to the environment, and several constituents in drainage exceed the limit of discharge from landfill site. Metals found in drainage exist in exchangeable fraction in waste rock and tailings. This means that if when it rains to mine waste containments, mine wastes can be pollutant to the environment by release of acidity and metals. As a result of simulation for hydraulic potentials and groundwater flow paths within the tailings, the simulated travel paths correlated well with the observed contaminant distribution. The plum disperse, both longitudinal and transverse dimensions, with time. Therefore liner system is a very important component in tailings containment system. As experimental results of liner development using tailings, tailings mixed with some portion of resin or cement may be used for liner because tailings with some additives have a very low hydraulic conductivity. (author). 39 refs.

Review of potential host rocks for radioactive waste disposal in the southeast United States-Southern Piedmont subregion

International Nuclear Information System (INIS)

1980-10-01

A literature study was conducted on the geology of the Southern Piedmont province in the states of Maryland, Virginia, North Carolina, South Carolina, and Georgia. The purpose was to identify geologic areas potentially suitable for containment of a repository for the long-term isolation of solidified radioactive waste. The crystalline rocks of the Southern Piedmont province range in age from Precambrian to Paleozoic, and are predominantly slates, phyllites, argillites, schists, metavolcanics, gneisses, gabbros, and granites. These rock units were classified as either favorable, potentially favorable, or unfavorable as potential study areas based on an evaluation of the geologic, hydrologic, and geotechnical characteristics. No socio-economic factors were considered. Rocks subjected to multiple periods of deformation and metamorphism, or described as highly fractured, or of limited areal extent were generally ranked as unfavorable. Potentially favorable rocks are primarily the high-grade metamorphic gneisses and granites. Sixteen areas were classified as being favorable for additional study. These areas are primarily large igneous granite plutons as follows: the Petersburg granite in Virginia; the Rolesville-Castallia, Churchland, and Landis plutons in North Carolina; the Liberty Hill, Winnsboro, and Ogden plutons in South Carolina; and the Siloam, Elberton, and six unnamed granite plutons in Georgia

Comprenhensive Program of Engineering and Geologic Surveys for Designing and Constructing Radioactive Waste Storage Facilities in Hard Rock Massifs

International Nuclear Information System (INIS)

Gupalo, T.; Milovidov, V.; Prokopoca, O.; Jardine, L.

2002-01-01

Geological, geophysical, and engineering-geological research conducted at the 'Yeniseisky' site obtained data on climatic, geomorphologic, geological conditions, structure and properties of composing rock, and conditions of underground water recharge and discharge. These results provide suficient information to make an estimate of the suitability of locating a radioactive waste (RW) underground isolation facility at the Nizhnekansky granitoid massif.

Technological project of serpentine raw material milling from Dobšiná heaps

Directory of Open Access Journals (Sweden)

Alena Pietriková

2005-11-01

Full Text Available Serpentine heaps in the surrounding of Dobšiná are an old ecological problem of the city and at the same time a suitable material for the production of MgCl2 and SiO2. The technology of the production is based on the chemical processing of the raw material, which is preceded by the raw material preparation comprising of the mechanical and hydraulic sorting, milling and the magnetic separation operations.

Production Of Bio fuel Starter From Biomass Waste Using Rocking Kiln Fluidized Bed System

International Nuclear Information System (INIS)

Mohamad Azman Che Mat Isa; Muhd Noor Muhd Yunus; Zulkafli Ghazali; Mohd Zaid Mohamed; Phongsakorn, P.T.; Mohamad Puad Abu

2014-01-01

The biggest biomass source in Malaysia comes from oil palm industry. According to the statistic in 2010, Malaysia produced 40 million tones per year of biomass of which 30 million tones of biomass originated from the oil palm industries. The biomass waste such as palm kernel shell can be used to produce activated carbon and bio fuel starter. A new type of rotary kiln, called Rocking Kiln Fluidized Bed (RKFB) was developed in Nuclear Malaysia to utilize the large amount of the biomass to produce high value added products. This system is capable to process biomass with complete combustion to produce bio fuel starter. With this system, the produced charcoal has calorific value, 33MJ/ kg that is better than bituminous coal with calorific value, 25-30 MJ/ kg. In this research, the charcoals produced were further used to produce the bio fuel starter. This paper will elaborate the experimental set-up of the Rocking Kiln Fluidized Bed (RKFB) for bio fuel starter production and the quality of the produced bio fuel starter. (author)

Effect of biotic and abiotic factors on soil microbial community diversity during primary succession on colliery spoil heaps

Czech Academy of Sciences Publication Activity Database

Elhottová, Dana; Frouz, Jan; Chroňáková, Alica; Malý, S.; Krištůfek, Václav; Kalčík, Jiří; Szili-Kovács, T.; Picek, T.

2004-01-01

Roč. 45, - (2004), s. 51 ISSN 0009-0646. [Kongres československé společnosti mikrobiologické /23./. 06.09.2004-09.09.2004, Brno] Keywords : soil microbial community * primary succession * colliery spoil heaps Subject RIV: EH - Ecology, Behaviour

Requirements for a long-term safety certification for chemotoxic substances stored in a final storage facility for high radioactive and heat-generating radioactive waste in rock salt formations

International Nuclear Information System (INIS)

Tholen, M.; Hippler, J.; Herzog, C.

2007-01-01

Within the scope of a project funded by the German Federal Ministry of Economics and Technology (Bundesministerium fuer Wirtschaft und Technologie, BMWi), a safety certification concept for a future permanent final storage for high radioactive and heat-generating radioactive waste (HAW disposal facility) in rock salt formations is being prepared. For a reference concept, compliance with safety requirements in regard to operational safety as well as radiological and non-radiological protection objectives related to long-term safety, including ground water protection, will be evaluated. This paper deals with the requirements for a long-term safety certification for the purpose of protecting ground water from chemotoxic substances. In particular, longterm safety certifications for the permanent disposal of radioactive waste in a HAW disposal facility in rock salt formations and for the dumping of hazardous waste in underground storage facilities in rock salt formations are first discussed, followed by an evaluation as to whether these methods can be applied to the long-term safety certification for chemotoxic substances. The authors find it advisable to apply the long-term safety certification for underground storage facilities to the long-term safety certification for chemotoxic substances stored in a HAW disposal facility in rock salt formations. In conclusion, a corresponding certification concept is introduced. (orig.)

Rock disposal problems identified

Energy Technology Data Exchange (ETDEWEB)

Knox, R

1978-06-01

Mathematical models are the only way of examining the return of radioactivity from nuclear waste to the environment over long periods of time. Work in Britain has helped identify areas where more basic data is required, but initial results look very promising for final disposal of high level waste in hard rock repositories. A report by the National Radiological Protection Board of a recent study, is examined.

Programme of research into the disposal of radioactive waste into geological formations. Studies on crystalline rock. Contract 059-78-1 WASUK. Final report: General studies of physical properties

International Nuclear Information System (INIS)

1981-11-01

This report covers the following topics: groundwater dating; heat transfer and associated thermal studies (in-situ heat transfer experiment; thermal rock and fluid mechanics studies; thermal convection; hydraulic permeability experiments; laboratory studies); corrosion and chemical compatibility studies (field and laboratory corrosion studies; waste - rock interactions). (U.K.)

Package materials, waste form

International Nuclear Information System (INIS)

Anon.

1980-01-01

The schedules for waste package development for the various host rocks were presented. The waste form subtask activities were reviewed, with the papers focusing on high-level waste, transuranic waste, and spent fuel. The following ten papers were presented: (1) Waste Package Development Approach; (2) Borosilicate Glass as a Matrix for Savannah River Plant Waste; (3) Development of Alternative High-Level Waste Forms; (4) Overview of the Transuranic Waste Management Program; (5) Assessment of the Impacts of Spent Fuel Disassembly - Alternatives on the Nuclear Waste Isolation System; (6) Reactions of Spent Fuel and Reprocessing Waste Forms with Water in the Presence of Basalt; (7) Spent Fuel Stabilizer Screening Studies; (8) Chemical Interactions of Shale Rock, Prototype Waste Forms, and Prototype Canister Metals in a Simulated Wet Repository Environment; (9) Impact of Fission Gas and Volatiles on Spent Fuel During Geologic Disposal; and (10) Spent Fuel Assembly Decay Heat Measurement and Analysis

Drill-back studies examine fractured, heated rock

International Nuclear Information System (INIS)

Wollenberg, H.A.; Flexser, S.; Myer, L.R.

1990-01-01

To investigate the effects of heating on the mineralogical, geochemical, and mechanical properties of rock by high-level radioactive waste, cores are being examined from holes penetrating locations where electric heaters simulated the presence of a waste canister, and from holes penetration natural hydrothermal systems. Results to date indicate the localized mobility and deposition of uranium in an open fracture in heated granitic rock, the mobility of U in a breccia zone in an active hydrothermal system in tuff, and the presence of U in relatively high concentration in fracture-lining material in tuff. Mechanical -- property studies indicate that differences in compressional- and shear-wave parameters between heated and less heated rock can be attributed to differences in the density of microcracks. Emphasis has shifted from initial studies of granitic rock at Stripa, Sweden to current investigations of welded tuff at the Nevada Test Site. 7 refs., 8 figs

Unsaturated flow and transport through fractured rock related to high-level waste repositories

International Nuclear Information System (INIS)

Evans, D.D.; Rasmussen, T.C.

1991-01-01

Research results are summarized for a US Nuclear Regulatory Commission contract with the University of Arizona focusing on field and laboratory methods for characterizing unsaturated fluid flow and solute transport related to high-level radioactive waste repositories. Characterization activities are presented for the Apache Leap Tuff field site. The field site is located in unsaturated, fractured tuff in central Arizona. Hydraulic, pneumatic, and thermal characteristics of the tuff are summarized, along with methodologies employed to monitor and sample hydrologic and geochemical processes at the field site. Thermohydrologic experiments are reported which provide laboratory and field data related to the effects conditions and flow and transport in unsaturated, fractured rock. 29 refs., 17 figs., 21 tabs

Radiation legacy of the USSR enterprises for mining, milling and processing of uranium ores: Conservation, decommissioning and environmental rehabilitation

International Nuclear Information System (INIS)

Burykin, A.A.; Iskra, A.A.; Karamushka, V.P.

2002-01-01

The long-term operation of USSR uranium mining and milling enterprises produced a great volume of low level radioactive waste in the form of rock spoil heaps (181 million m 3 ), hydro-metallurgical plants tailings dumps (340 million m 3 ) and basins of mine waters (200 million m 3 ) with total activity of 25.1·10 15 Bq (670 kCi). The total area occupied by the dumps is about 180 km 2 . The paper presents brief characteristics of the activities of uranium ore mining enterprises located at the CIS countries' territories, their wastes' status and describes measures for rehabilitation and restoration of territories of the Soviet uranium mining and metallurgical complex. (author)

A review and synthesis of international proposals for the disposal of high-level radioactive wastes into crystalline rock formations

International Nuclear Information System (INIS)

1981-05-01

Examination of the broad range of international concepts for the disposal of high-level radioactive wastes into crystalline rock formations has indicated that systems based upon solid waste units provide the greatest degree of engineering control and security. Three particular disposal concepts are considered worthy of detailed evaluation. In order of priority these are:-tunnel networks with 'in-floor' waste emplacement; matrix of vertical emplacement holes drilled from the surface; tunnel networks with 'in-room' waste emplacement. A review of the international literature has shown that at least ten countries have embarked upon study programmes, but only five have developed detailed conceptual design proposals. These are:- Canada, France, Sweden, the United Kingdom, and the United States. Differing economic, environmental, historical and political circumstances have influenced the pattern of international studies and, to the uninitiated, these factors may obscure some of the relevant technical considerations. Nevertheless, a broad technical concensus is apparent in that all countries currently favour tunnel networks with 'in-floor' waste emplacement. The subject is discussed in detail. (author)

Characterization and evaluation of sites for deep geological disposal of radioactive waste in fractured rocks. Proceedings

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-09-01

The third Aespoe International Seminar was organised by SKB to assess the state of the art in characterisation and evaluation of sites for deep geological disposal of radioactive waste in fractured rocks. Site characterisation and evaluation are important elements for determining the site suitability and long-term safety of a geological repository for radioactive waste disposal. Characterisation work also provides vital information for the design of the underground facility and the engineered barrier system that will contain the waste. The aim of the seminar was to provide a comprehensive assessment of the current know-how on this topic based on world-wide experience from more than 20 years of characterisation and evaluation work. The seminar, which was held at the Aespoe Hard Rock Laboratory was attended by 72 scientists from 10 different countries. The program was divided into four sessions of which two were run in parallel. A total of 38 oral and 5 poster presentations were given at the seminar. The presentations gave a comprehensive summary of recently completed and current work on site characterisation, modelling and application in performance assessments. The results presented at the seminar generally show that significant progress has been made in this field during the last decade. New characterisation techniques have become available, strategies for site investigations have developed further, and model concepts and codes have reached new levels of refinement. Data obtained from site characterisation have also successfully been applied in several site specific performance assessments. The seminar clearly showed that there is a solid scientific basis for assessing the suitability of sites for actual repositories based on currently available site characterisation technology and modelling capabilities. Separate abstracts have been prepared for 38 of the presentations

Flow behavior and mobility of contaminated waste rock materials in the abandoned Imgi mine in Korea

Science.gov (United States)

Jeong, S. W.; Wu, Y.-H.; Cho, Y. C.; Ji, S. W.

2018-01-01

Incomplete mine reclamation can cause ecological and environmental impacts. This paper focuses on the geotechnical and rheological characteristics of waste rock materials, which are mainly composed of sand-size particles, potentially resulting in mass movement (e.g., slide or flow) and extensive acid mine drainage. To examine the potential for contaminant mobilization resulting from physicochemical processes in abandoned mines, a series of scenario-based debris flow simulations was conducted using Debris-2D to identify different hazard scenarios and volumes. The flow behavior of waste rock materials was examined using a ball-measuring rheometric apparatus, which can be adapted for large particle samples, such as debris flow. Bingham yield stresses determined in controlled shear rate mode were used as an input parameter in the debris flow modeling. The yield stresses ranged from 100 to 1000 Pa for shear rates ranging from 10- 5 to 102 s- 1. The results demonstrated that the lowest yield stress could result in high mobility of debris flow (e.g., runout distance > 700 m from the source area for 60 s); consequently, the material contaminants may easily reach the confluence of the Suyoung River through a mountain stream. When a fast slide or debris flow occurs at or near an abandoned mine area, it may result in extremely dynamic and destructive geomorphological changes. Even for the highest yield stress of debris flow simulation (i.e., τy = 2000 Pa), the released debris could flow into the mountain stream; therefore, people living near abandoned mines may become exposed to water pollution throughout the day. To maintain safety at and near abandoned mines, the physicochemical properties of waste materials should be monitored, and proper mitigation measures post-mining should be considered in terms of both their physical damage and chemical pollution potential.

Determination of soil mechanics of salt rock as a potential backfilling material in an underground repository

International Nuclear Information System (INIS)

Kappei, G.

1987-09-01

Within the framework of the research and development project 'Backfilling and sealing of boreholes, chambers and roadways in a final dump', the Institute for Underground Dumping chose - from the broad range of possible stowing materials - the material 'salt spoil' and investigated its soil-mechanical properties in detail. Besides the implementation of soil-mechanical standard analyses (determination of the grain size distribution, bulk density, limits of storage density, proctor density, permeabilities, and shear strength) of two selected salt spoils (heap salt and rock salt spoil), the studies concentrated on the determination of the compression behaviour of salt spoil. In order to obtain data on the compaction behaviour of this material in the case of increasing stress, compression tests with obstructed lateral expansion were carried out on a series of spoil samples differing mainly in the composition of grain sizes. In addition to this, for a small number of samples of rock salt spoil, the creep behaviour at constant stress was determined after the compaction phase. (orig./RB) [de

Final environmental statement related to the Western Nuclear, Inc., Split Rock Uranium Mill (Fremont County, Wyoming)

International Nuclear Information System (INIS)

1980-02-01

The proposed action is the renewal of Source Material License SUA-56 (with amendments) issued to Western Nuclear, Inc. (WNI), for the operation of the Split Rock Uranium Mill near Jeffrey City and the Green Mountain Ion-Exchange Facility, both in Fremont County, Wyoming. The license also permits possession of material from past operations at four ancillary facilities in the Gas Hills mining area - the Bullrush, Day-Loma, Frazier-Lamac, and Rox sites (Docket No. 40-1162). However, although heap leaching operations were previously authorized at Frazier-Lamac, there has never been any processing of material at this site. The Split Rock mill is an acid-leach, ion-exchange and solvent-extraction uranium-ore processing mill with a design capacity of 1540 MT (1700 tons) of ore per day. WNI has proposed by license amendment request to increase the storage capacity of the tailings ponds in order to permit the continuation of present production rates of U 3 O 8 through 1996 using lower-grade ores

Optimization of Eisenia fetida stocking density for the bioconversion of rock phosphate enriched cow dung–waste paper mixtures

International Nuclear Information System (INIS)

Unuofin, F.O.; Mnkeni, P.N.S.

2014-01-01

Highlights: • Vermidegradation of RP-enriched waste mixtures is dependent on E. fetida stocking density. • A stocking density of 12.5 g-worms kg -1 resulted in highly humified vermicomposts. • P release from RP-enriched waste vermicomposts increases with E. fetida stocking density. • RP-enriched waste vermicomposts had no inhibitory effect on seed germination. - Abstract: Vermitechnology is gaining recognition as an environmental friendly waste management strategy. Its successful implementation requires that the key operational parameters like earthworm stocking density be established for each target waste/waste mixture. One target waste mixture in South Africa is waste paper mixed with cow dung and rock phosphate (RP) for P enrichment. This study sought to establish optimal Eisenia fetida stocking density for maximum P release and rapid bioconversion of RP enriched cow dung–paper waste mixtures. E. fetida stocking densities of 0, 7.5, 12.5, 17.5 and 22.5 g-worms kg −1 dry weight of cow dung–waste paper mixtures were evaluated. The stocking density of 12.5 g-worms kg −1 resulted in the highest earthworm growth rate and humification of the RP enriched waste mixture as reflected by a C:N ratio of <12 and a humic acid/fulvic acid ratio of >1.9 in final vermicomposts. A germination test revealed that the resultant vermicompost had no inhibitory effect on the germination of tomato, carrot, and radish. Extractable P increased with stocking density up to 22.5 g-worm kg −1 feedstock suggesting that for maximum P release from RP enriched wastes a high stocking density should be considered

Optimization of Eisenia fetida stocking density for the bioconversion of rock phosphate enriched cow dung–waste paper mixtures

Energy Technology Data Exchange (ETDEWEB)

Unuofin, F.O., E-mail: funmifrank2009@gmail.com; Mnkeni, P.N.S., E-mail: pmnkeni@ufh.ac.za

2014-11-15

Highlights: • Vermidegradation of RP-enriched waste mixtures is dependent on E. fetida stocking density. • A stocking density of 12.5 g-worms kg{sup -1} resulted in highly humified vermicomposts. • P release from RP-enriched waste vermicomposts increases with E. fetida stocking density. • RP-enriched waste vermicomposts had no inhibitory effect on seed germination. - Abstract: Vermitechnology is gaining recognition as an environmental friendly waste management strategy. Its successful implementation requires that the key operational parameters like earthworm stocking density be established for each target waste/waste mixture. One target waste mixture in South Africa is waste paper mixed with cow dung and rock phosphate (RP) for P enrichment. This study sought to establish optimal Eisenia fetida stocking density for maximum P release and rapid bioconversion of RP enriched cow dung–paper waste mixtures. E. fetida stocking densities of 0, 7.5, 12.5, 17.5 and 22.5 g-worms kg{sup −1} dry weight of cow dung–waste paper mixtures were evaluated. The stocking density of 12.5 g-worms kg{sup −1} resulted in the highest earthworm growth rate and humification of the RP enriched waste mixture as reflected by a C:N ratio of <12 and a humic acid/fulvic acid ratio of >1.9 in final vermicomposts. A germination test revealed that the resultant vermicompost had no inhibitory effect on the germination of tomato, carrot, and radish. Extractable P increased with stocking density up to 22.5 g-worm kg{sup −1} feedstock suggesting that for maximum P release from RP enriched wastes a high stocking density should be considered.

Heterogeneous redox conditions, arsenic mobility, and groundwater flow in a fractured-rock aquifer near a waste repository site in New Hampshire, USA

Science.gov (United States)

Anthropogenic sources of carbon from landfill or waste leachate can promote reductive dissolution of in situ arsenic (As) and enhance the mobility of As in groundwater. Groundwater from residential-supply wells in a fractured crystalline-rock aquifer adjacent to a Superfund site ...

Modeling fluid-rock interaction at Yucca Mountain, Nevada

International Nuclear Information System (INIS)

Viani, B.E.; Bruton, C.J.

1992-08-01

Volcanic rocks at Yucca Mountain, Nevada aie being assessed for their suitability as a potential repository for high-level nuclear waste. Recent progress in modeling fluid-rock interactions, in particular the mineralogical and chemical changes that may accompany waste disposal at Yucca Mountain, will be reviewed in this publication. In Part 1 of this publication, ''Geochemical Modeling of Clinoptilolite-Water Interactions,'' solid-solution and cation-exchange models for the zeolite clinoptilolite are developed and compared to experimental and field observations. At Yucca Mountain, clinoptilolite which is found lining fractures and as a major component of zeolitized tuffs, is expected to play an important role in sequestering radionuclides that may escape from a potential nuclear waste repository. The solid-solution and ion-exchange models were evaluated by comparing predicted stabilities and exchangeable cation distributions of clinoptilolites with: (1) published binary exchange data; (2) compositions of coexisting clinoptilolites and formation waters at Yucca Mountain; (3) experimental sorption isotherms of Cs and Sr on zeolitized tuff, and (4) high temperature experimental data. Good agreement was found between predictions and expertmental data, especially for binary exchange and Cs and Sr sorption on clinoptilolite. Part 2 of this publication, ''Geochemical Simulation of Fluid-Rock Interactions at Yucca Mountain,'' describes preliminary numerical simulations of fluid-rock interactions at Yucca Mountain. The solid-solution model developed in the first part of the paper is used to evaluate the stability and composition of clinciptilolite and other minerals in the host rock under ambient conditions and after waste emplacement

Proceedings of the establishment conference of Professional Committee on Waste Underground Disposal of Chinese Society for Rock Mechanics and Engineering and the first academic seminar

International Nuclear Information System (INIS)

2006-07-01

Approved by the China Association for Science and Technology, Chinese Society for Rock Mechanics and Engineering newly established 'Professional Committee on Waste Underground Disposal'. The committee will organise the national and international academic exchange, and provide advice on discipline development, sustainable industrial development, environmental protection, etc.. This is the establishing conference of the professional committee, as well as the first academic seminar. The following topics on waste underground disposal are discussed: the theory, practice and exploration, project examples, new technologies and new methods. The contents include: waste disposal technology in the new century, the geological disposal of high level radioactive waste, LLW and ILW underground waste disposal, urban and industrial waste underground disposal, and etc.

Terminal storage of radioactive waste in geologic formations

International Nuclear Information System (INIS)

Lomenick, T.F.

1976-01-01

The principal aim of the National Waste Terminal Storage (NWTS) program is to develop pilot plants and, ultimately, repositories in several different rock formations in various parts of the country. Rocks such as salt, shale, limestone, granite, schists, and serpentinite may all qualify as host media for the disposition of radioactive wastes in the proper environments. In general, the only requirement for any rock formation or storage site is that it contain any emplaced wastes for so long as it takes for the radioactive materials to decay to innocuous levels. This requirement, though, is a formidable one as some of the wastes will remain active for periods of hundreds of thousands of years and the physical and chemical properties of rocks that govern circulating groundwater and hence containment, are difficult to determine and define. Nevertheless, there are many rock types and a host of areas throughout the country where conditions are promising for the development of waste repositories. Some of these are discussed below

Development of the Method of Bacterial Leaching of Metals out of Low-Grade Ores, Rocks, and Industrial Wastes Using Neutron Activation Analysis

CERN Document Server

Tsertsvadze, L A; Petriashvili, Sh G; Chutkerashvili, D G; Kirkesali, E I; Frontasyeva, M V; Pavlov, S S; Gundorina, S F

2001-01-01

The results of preliminary investigations aimed at the development of an economical and easy to apply technique of bacterial leaching of rare and valuable metals out of low-grade ores, complex composition ores, rocks, and industrial wastes in Georgia are discussed. The main groups of microbiological community of the peat suspension used in the experiments of bacterial leaching are investigated and the activity of particular microorganisms in the leaching of probes with different mineral compositions is assessed. The element composition of the primary and processed samples was investigated by the epithermal neutron activation analysis method and the enrichment/subtraction level is estimated for various elements. The efficiency of the developed technique to purify wastes, extract some scrace metals, and enrich ores or rocks in some elements, e.g. Au, U, Th, Cs, Sr, Rb, Sc, Zr, Hf, Ta, Gd, Er, Lu, Ce, etc., is demonstrated.

Modeling transient heat transfer in nuclear waste repositories.

Science.gov (United States)

Yang, Shaw-Yang; Yeh, Hund-Der

2009-09-30

The heat of high-level nuclear waste may be generated and released from a canister at final disposal sites. The waste heat may affect the engineering properties of waste canisters, buffers, and backfill material in the emplacement tunnel and the host rock. This study addresses the problem of the heat generated from the waste canister and analyzes the heat distribution between the buffer and the host rock, which is considered as a radial two-layer heat flux problem. A conceptual model is first constructed for the heat conduction in a nuclear waste repository and then mathematical equations are formulated for modeling heat flow distribution at repository sites. The Laplace transforms are employed to develop a solution for the temperature distributions in the buffer and the host rock in the Laplace domain, which is numerically inverted to the time-domain solution using the modified Crump method. The transient temperature distributions for both the single- and multi-borehole cases are simulated in the hypothetical geological repositories of nuclear waste. The results show that the temperature distributions in the thermal field are significantly affected by the decay heat of the waste canister, the thermal properties of the buffer and the host rock, the disposal spacing, and the thickness of the host rock at a nuclear waste repository.

Reference waste package environment report

International Nuclear Information System (INIS)

Glassley, W.E.

1986-01-01

One of three candidate repository sites for high-level radioactive waste packages is located at Yucca Mountain, Nevada, in rhyolitic tuff 700 to 1400 ft above the static water table. Calculations indicate that the package environment will experience a maximum temperature of ∼230 0 C at 9 years after emplacement. For the next 300 years the rock within 1 m of the waste packages will remain dehydrated. Preliminary results suggest that the waste package radiation field will have very little effect on the mechanical properties of the rock. Radiolysis products will have a negligible effect on the rock even after rehydration. Unfractured specimens of repository rock show no change in hydrologic characteristics during repeated dehydration-rehydration cycles. Fractured samples with initially high permeabilities show a striking permeability decrease during dehydration-rehydration cycling, which may be due to fracture healing via deposition of silica. Rock-water interaction studies demonstrate low and benign levels of anions and most cations. The development of sorptive secondary phases such as zeolites and clays suggests that anticipated rock-water interaction may produce beneficial changes in the package environment

Predictability of the evolution of hydrogeological and hydrogeochemical systems; geological disposal of nuclear waste in crystalline rocks

International Nuclear Information System (INIS)

Murphy, W.M.; Diodato, D.M.

2009-01-01

Confidence in long-term geologic isolation of high-level nuclear waste and spent nuclear fuel requires confidence in predictions of the evolution of hydrogeological and hydrogeochemical systems. Prediction of the evolution of hydrogeological and hydrogeochemical systems is based on scientific understanding of those systems in the present - an understanding that can be tested with data from the past. Crystalline rock settings that have been geologically stable for millions of years and longer offer the potential of predictable, long-term waste isolation. Confidence in predictions of geologic isolation of radioactive waste can measured by evaluating the extent to which those predictions and their underlying analyses are consistent with multiple independent lines of evidence identified in the geologic system being analysed, as well as with evidence identified in analogs to that geologic system. The proposed nuclear waste repository at Yucca Mountain, Nevada, United States, differs in significant ways from potential repository sites being considered by other nations. Nonetheless, observations of hydrogeological and hydrogeochemical systems of Yucca Mountain and Yucca Mountain analogs present multiple independent lines of evidence that can be used in evaluating long-term predictions of the evolution of hydrogeological and hydrogeochemical systems at Yucca Mountain. (authors)

Application of the iron-enriched basalt waste form for immobilizing commercial transuranic waste

International Nuclear Information System (INIS)

Owen, D.E.

1981-08-01

The principal sources of commercial transuranic (TRU) waste in the United States are identified. The physical and chemical nature of the wastes from these sources are discussed. The fabrication technique and properties of iron-enriched basalt, a rock-like waste form developed for immobilizing defense TRU wastes, are discussed. The application of iron-enriched basalt to commercial TRU wastes is discussed. Review of commercial TRU wastes from mixed-oxide fuel fabrication, light water reactor fuel reprocessing, and miscellaneous medical, research, and industrial sources, indicates that iron-enriched basalt is suitable for most types of commercial TRU wastes. Noncombustible TRU wastes are dissolved in the high temperature, oxidizing iron-enriched basalt melt. Combustible TRU wastes are immobilized in iron-enriched basalt by incinerating the wastes and adding the TRU-bearing ash to the melt. Casting and controlled cooling of the melt produces a devitrified, rock-like iron-enriched basalt monolith. Recommendations are given for testing the applicability of iron-enriched basalt to commercial TRU wastes

Mine waste disposal and managements

Energy Technology Data Exchange (ETDEWEB)

Cheong, Young Wook; Min, Jeong Sik; Kwon, Kwang Soo; Kim, Ok Hwan; Kim, In Kee; Song, Won Kyong; Lee, Hyun Joo [Korea Institute of Geology Mining and Materials, Taejon (Korea)

1998-12-01

Acid Rock Drainage (ARD) is the product formed by the atmospheric oxidation of the relatively common pyrite and pyrrhotite. Waste rock dumps and tailings containing sulfide mineral have been reported at toxic materials producing ARD. Mining in sulphide bearing rock is one of activity which may lead to generation and release of ARD. ARD has had some major detrimental affects on mining areas. The purpose of this study was carried out to develop disposal method for preventing contamination of water and soil environment by waste rocks dump and tailings, which could discharge the acid drainage with high level of metals. Scope of this study was as following: environmental impacts by mine wastes, geochemical characteristics such as metal speciation, acid potential and paste pH of mine wastes, interpretation of occurrence of ARD underneath tailings impoundment, analysis of slope stability of tailings dam etc. The following procedures were used as part of ARD evaluation and prediction to determine the nature and quantities of soluble constituents that may be washed from mine wastes under natural precipitation: analysis of water and mine wastes, Acid-Base accounting, sequential extraction technique and measurement of lime requirement etc. In addition, computer modelling was applied for interpretation of slope stability od tailings dam. (author). 44 refs., 33 tabs., 86 figs.

Dynamic of active microorganisms inhabiting a bioleaching industrial heap of low‐grade copper sulfide ore monitored by real‐time PCR and oligonucleotide prokaryotic acidophile microarray

Science.gov (United States)

Remonsellez, Francisco; Galleguillos, Felipe; Moreno‐Paz, Mercedes; Parro, Víctor; Acosta, Mauricio; Demergasso, Cecilia

2009-01-01

Summary The bioleaching of metal sulfide has developed into a very important industrial process and understanding the microbial dynamic is key to advancing commercial bioleaching operations. Here we report the first quantitative description of the dynamic of active communities in an industrial bioleaching heap. Acidithiobacillus ferrooxidans was the most abundant during the first part of the leaching cycle, while the abundance of Leptospirillum ferriphilum and Ferroplasma acidiphilum increased with age of the heap. Acidithiobacillus thiooxidans kept constant throughout the leaching cycle, and Firmicutes group showed a low and a patchy distribution in the heap. The Acidiphilium‐like bacteria reached their highest abundance corresponding to the amount of autotrophs. The active microorganisms in the leaching system were determined using two RNA‐based sensitive techniques. In most cases, the 16S rRNA copy numbers of At. ferrooxidans, L. ferriphilum, At. thiooxidans and F. acidiphilum, was concomitant with the DNA copy numbers, whereas Acidiphilium‐like bacteria and some Firmicutes members did not show a clear correlation between 16S rRNA accumulation and DNA copy numbers. However, the prokaryotic acidophile microarray (PAM) analysis showed active members of Alphaproteobacteria in all samples and of Sulfobacillus genus in older ones. Also, new active groups such as Actinobacteria and Acidobacterium genus were detected by PAM. The results suggest that changes during the leaching cycle in chemical and physical conditions, such as pH and Fe3+/Fe2+ ion rate, are primary factors shaping the microbial dynamic in the heap. PMID:21255296

Increasing shaft depth with rock hoisting to the surface. [USSR

Energy Technology Data Exchange (ETDEWEB)

Durov, E.M.

1982-06-01

Schemes of shaft construction with increasing shaft depth depend on: shaft depth, shaft diameter, types of hoisting systems, schemes of shaft reinforcement. Investigations carried out in underground coal mines in the USSR show that waste rock haulage to the surface by an independent hoisting system is most economical. Installation of this system depends on the existing hoisting scheme. When one of the operating cages or skips can be removed without a negative influence on mine operation the system of rock waste hoisting is used. The hoisting bucket used for rock removal from the shaft bottom moves in the shaft section from which one of the cages or skips has been removed. Examples of using this scheme in Donbass, Kuzbass and other coal basins are given. Economic aspects of waste material hoisting to the surface are analyzed. The system is economical when the remaining hoisting system can accept additional loads after removal of a cage or skip from the shaft. Investigations show that use of a bucket with a capacity from 2.5 to 3.0 m/sup 3/ for waste rock removal from the shaft being modernized and deepened is most economical.

Alteration of national glass in radioactive waste repository host rocks: A conceptional review

International Nuclear Information System (INIS)

Apps, J.A.

1987-01-01

The storage of high-level radioactive wastes in host rocks containing natural glass has potential chemical advantages, especially if the initial waste temperatures are as high as 250 0 C. However, it is not certain how natural glasses will decompose when exposed to an aqueous phase in a repository environment. The hydration and devitrification of both rhyolitic and natural basaltic natural glasses are reviewed in the context of hypothetical thermodynamic phase relations, infrared spectroscopic data and laboratory studies of synthetic glasses exposed to steam. The findings are compared with field observations and laboratory studies of hydrating and devitrifying natural glasses. The peculiarities of the dependence of hydration and devitrification behavior on compositional variation is noted. There is substantial circumstantial evidence to support the belief that rhyolitic glasses differ from basaltic glasses in their thermodynamic stability and their lattice structure, and that this is manifested by a tendency of the former to hydrate rather than devitrify when exposed to water. Further research remains to be done to confirm the differences in glass structure, and to determine both physically and chemically dependent properties of natural glasses as a function of composition

Critical parameters in the dump and heap leaching of gold, silver, copper and uranium: permeability, solution delivery and solution recovery

Energy Technology Data Exchange (ETDEWEB)

Lastra, M.K.; Chase, C.K.

1984-02-01

Critical to successful dump and heap leaching for gold, silver, copper and uranium are factors such as permeability, solution delivery to the ore, and solution recovery. This paper deals with possible techniques for successful accomplishment of these three factors. New developments as well as older techniques are discussed, together with rationals for use of some techniques in reference to others. The authors hope to present a checklist so that the ideal application to individual mine situations can be achieved. This involves a discussion of the merits of each different method and the situations for most logical application. It is hoped that such discussion will broaden the geographic areas where dump and heap leaching can be applied to include greater winter cold and tropical regions of large amounts of rainfall.

Critical parameters in the dump and heap leaching of gold, silver, copper and uranium: permeability, solution delivery and solution recovery

International Nuclear Information System (INIS)

Lastra, M.K.; Chase, C.K.

1984-01-01

Critical to successful dump and heap leaching for gold, silver, copper and uranium are factors such as permeability, solution delivery to the ore, and solution recovery. This paper deals with possible techniques for successful accomplishment of these three factors. New developments as well as older techniques are discussed, together with rationals for use of some techniques in reference to others. The authors hope to present a checklist so that the ideal application to individual mine situations can be achieved. This involves a discussion of the merits of each different method and the situations for most logical application. It is hoped that such discussion will broaden the geographic areas where dump and heap leaching can be applied to include greater winter cold and tropical regions of large amounts of rainfall

Uraniferous minerals heap leaching process by counter techique

International Nuclear Information System (INIS)

Fuentes G, D.A.

1978-01-01

An experimental study was made at laboratory level with respect to a process for the treatment of an uranium ore by counter current acid heap leaching with maturity periods and washing. This mineral with an average grade of 0.24% of U 3 O 8 from the levels zero-fourty of the El Nopal uraniferous deposit, located in the Sierra of Pena Blanca, State of Chihuahua (Mexico). The process which is proposed consist of 4 consecutive stages: a) The prehumectation with a fertile solution of a 0.0034 g U 3 O 8 /1 and 3 g H 2 SO 4 /l concentration, b) The counter current acid attack, c) The maturity or hardening, d) The washing with current water. The relaton liquid-solid in the stages of prehumectation, acid attack, as well as washing stage was of 0.3 m 3 /t. The average efficiency was of 77% of recovered *uranium. (author)

PENGEMBANGAN METODE SINTESIS FURFURAL BERBAHAN DASAR CAMPURAN LIMBAH PERTANIAN DALAM RANGKA MEWUJUDKAN PRINSIP GREEN CHEMISTRY (Development Of Synthesis Method Of Furfural From Compost Heap Mixture To Reach Out Green Chemistry Principles

Directory of Open Access Journals (Sweden)

Mitarlis Mitarlis

2011-11-01

Full Text Available ABSTRAK Penelitian pengembangan metode sintesis furfural dengan bahan dasar campuran limbah pertanian dilakukan dengan tujuan untuk menentukan waktu pemanasan dan konsentrasi asam optimum serta mewujudkan prinsip green chemistry. Dalam penelitian ini digunakan campuran limbah pertanian ampas tebu, limbah daun nanas dan limbah tanaman jagung dengan perbandingan 1:1:1. Proses sintesis melalui tahap hidrolisis pentosan, dehidrasi, dan siklodehidrasi untuk membentuk furfural dengan menggunakan alat refluks termodifkasi. Identifikasi furfural menggunakan uji warna dengan anilin asetat, uji indeks bias, spektrofotometer UV-Vis, dan IR, serta GC. Analisis pemenuhan prinsip green chemistry menggunakan daftar ceck 12 prinsip green chemstry. Hasil penelitian menunjukkan bahwa: Waktu pemanasan dan konsentrasi asam sulfat optimum pada pembuatan furfural dari campuran limbah pertanian adalah 5 jam dan konsentrasi asam sulfat 10% (1,876 M dengan rendemen sebesar 5,58%. Metode sintesis furfural yang dikembangkan dapat memenuhi 11 dari 12 prinsip green chemistry yang telah ditetapkan. ABSTRACT The study of developing furfural synthesis method  from  compost heap mixture had been done to determine  optimum condition for this process and  to reach out the green chemistry principles. In this research, the compost heap mixture is from three kinds of compost heap (bagasse, pineapple leaf, waste of corn plant with same amount (1:1:1. The steps of furfural production process are hydrolysis of pentose by sulfuric acid, dehydration, and cyclodehydration to form furfural. It was produced by using a modification reflux apparatus. Identify of furfural product by  using qualitative analysis color test with aniline acetate, refractive index test, UV-Vis,  IR spectrophotometer, and GC. Green chemistry principles are analyzed by using check list of 12 principles of green chemistry.  Based on this research was obtained that the optimum concentration of sulfuric acid is

Solid as a rock

International Nuclear Information System (INIS)

Pincus, H.J.

1984-01-01

Recent technologic developments have required a more comprehensive approach to the behavior of rock mass or rock substance plus discontinuities than was adequate previously. This work considers the inherent problems in such operations as the storage of hot or cold fluids in caverns and aquifers, underground storage of nuclear waste, underground recovery of heat from hydrocarbon fuels, tertiary recovery of oil by thermal methods, rapid excavation of large openings at shallow to great depths and in hostile environments, and retrofitting of large structures built on or in rock. The standardization of methods for determining rock properties is essential to all of the activities described, for use not only in design and construction but also in site selection and post-construction monitoring. Development of such standards is seen as a multidisciplinary effort

Research into basic rocks types

International Nuclear Information System (INIS)

1993-06-01

Teollisuuden Voima Oy (TVO) has carried out research into basic rock types in Finland. The research programme has been implemented in parallel with the preliminary site investigations for radioactive waste disposal in 1991-1993. The program contained two main objectives: firstly, to study the properties of the basic rock types and compare those with the other rock types under the investigation; secondly, to carry out an inventory of rock formations consisting of basic rock types and suitable in question for final disposal. A study of environmental factors important to know regarding the final disposal was made of formations identified. In total 159 formations exceeding the size of 4 km 2 were identified in the inventory. Of these formations 97 were intrusive igneous rock types and 62 originally extrusive volcanic rock types. Deposits consisting of ore minerals, industrial minerals or building stones related to these formations were studied. Environmental factors like natural resources, protected areas or potential for restrictions in land use were also studied

Rock stress measurements in the Grimsel Underground Rock Laboratory and their geological interpretation

International Nuclear Information System (INIS)

Braeuer, V.; Heusermann, S.; Pahl, A.

1989-01-01

Rock stress is being studied as part of the Swiss-German cooperation between the National Cooperative for the Storage of Radioactive Waste (NAGRA), the Research Centre for Environmental Sciences (GSF), and the Federal Institute for Geosciences and Natural Resources (BGR) in the Grimsel Rock Laboratory in Switzerland. Several methods and various equipment for measuring rock stress have been developed and tested in an approximately 200-m borehole drilled from a gallery at a depth of 450 m. The measurements were made continually during overcoring; the data were recorded and processed in a computer located downhole or outside the borehole. The results of the overcoring tests and of frac tests indicate a principle horizontal stress of 25-40 MPa, directed mainly NW-SE. Detailed geological mapping shows relationships between stress and rock structure. A zone of nearly unfractured rock exhibits an increase in stress and a change in stress direction. (orig.)

Uranium production and environmental restoration at the Priargunsky Centre, Russian Federation

International Nuclear Information System (INIS)

Boitsov, A.V.; Nikolsky, A.L.; Chernigov, V.G.; Ovseichuk, V.A.

2002-01-01

State JSK 'Priargunsky Mining-Chemical Production Association' (PPGHO) has been the only active uranium production centre in Russia during the last decade. Mining has operated since 1968, and derives from resources in 19 volcanic-type deposits of Streltsovsk U-ore region, which covers an area of 150 km 2 . The average U grade is about 0.2%. Ten deposits have been brought into production: eight by underground mines and two by open pits. Milling and processing has been carried out since 1974 at the local hydrometallurgical plant by sulphuric acid leaching with subsequent recovery by a sorption-extraction ion exchange scheme. The high level of total production (over 100,000 mtU through 2000) marks it as one of the outstanding uranium production districts worldwide. Significant amounts of wastes have been accumulated. The main sources of the environmental contamination are: 30 piles of waste rocks and sub-grade ores, mine waters, milling and sulphuric acid plant tailings. The following activities are performed to decrease the negative impact on the environment: rehabilitation of waste rock dumps and open pits utilization of waste rock for industrial needs, heap and in situ leach mining of low-grade ores, construction of dams and intercepting wells below the tailings, hydrogeological monitoring and waste water treatment plant modernization. Environmental activities, including rehabilitation of the impacted territories and also waste utilization will be realized after final closure takes place. (author)

Super analog computer for evaluating the safety of buried radioactive waste

International Nuclear Information System (INIS)

Cohen, B.L.

1980-01-01

It is argued that the past use of digital computer programs for evaluating the safety of buried radioactive waste has been largely wasteful and dangerously delusive. It is suggested to use actual rocks as the analog of buried waste. The problem of comparable rates of leaching of radioactive waste and of natural rock is discussed. Two examples are given of the use of natural rock as an ''analog computer'': one for high-level radioactive waste, and one for low-level radioactive waste. Digital computers have not contributed anything to two crucial questions: Can shafts be securely sealed. Does the heat crack the rock or have important effects on its chemistry. 4 refs

Redox front formation in an uplifting sedimentary rock sequence: An analogue for redox-controlling processes in the geosphere around deep geological repositories for radioactive waste

International Nuclear Information System (INIS)

Yoshida, H.; Metcalfe, R.; Yamamoto, K.; Murakami, Y.; Hoshii, D.; Kanekiyo, A.; Naganuma, T.; Hayashi, T.

2008-01-01

Subsurface redox fronts control the mobilization and fixation of many trace elements, including potential pollutants such as certain radionuclides. Any safety assessment for a deep geological repository for radioactive wastes needs to take into account adequately the long-term redox processes in the geosphere surrounding the repository. To build confidence in understanding these processes, a redox front in a reduced siliceous sedimentary rock distributed in an uplifting area in Japan has been studied in detail. Geochemical analyses show increased concentrations of Fe and trace elements, including rare earth elements (REEs), at the redox front, even though concentrations of reduced rock matrix constituents show little change. Detailed SEM observations revealed that fossilized microorganisms composed of amorphous granules made exclusively of Fe and Si occur in the rock's pore space. Microbial 16S rDNA analysis suggests that there is presently a zonation of different bacterial groups within the redox band, and bacterial zonation played an important role in the concentration of Fe-oxyhydroxides at the redox front. These water-rock-microbe interactions can be considered analogous to the processes occurring in the redox fronts that would develop around geological repositories for radioactive waste. Once formed, the Fe-oxyhydroxides within such a front would be preserved even after reducing conditions resume following repository closure

Redox front formation in an uplifting sedimentary rock sequence: An analogue for redox-controlling processes in the geosphere around deep geological repositories for radioactive waste

Energy Technology Data Exchange (ETDEWEB)

Yoshida, H. [Nagoya University Museum, Material Research Section, Furocho, Nagoya 464-8602 (Japan)], E-mail: dora@num.nagoya-u.ac.jp; Metcalfe, R. [Quintessa Japan, Queen' s Tower A7-707, Minatomirai, Yokohama 220-6007 (Japan); Yamamoto, K. [Nagoya University Museum, Material Research Section, Furocho, Nagoya 464-8602 (Japan); Murakami, Y. [Japan Atomic Energy Agency (JAEA), Tono Geoscience Centre (Japan); Hoshii, D.; Kanekiyo, A.; Naganuma, T. [Hiroshima University, Higashi Hiroshima, Kagamiyama 1-4-4 (Japan); Hayashi, T. [Asahi University, Department of Dental Pharmacology, Hozumi, Gifu (Japan)

2008-08-15

Subsurface redox fronts control the mobilization and fixation of many trace elements, including potential pollutants such as certain radionuclides. Any safety assessment for a deep geological repository for radioactive wastes needs to take into account adequately the long-term redox processes in the geosphere surrounding the repository. To build confidence in understanding these processes, a redox front in a reduced siliceous sedimentary rock distributed in an uplifting area in Japan has been studied in detail. Geochemical analyses show increased concentrations of Fe and trace elements, including rare earth elements (REEs), at the redox front, even though concentrations of reduced rock matrix constituents show little change. Detailed SEM observations revealed that fossilized microorganisms composed of amorphous granules made exclusively of Fe and Si occur in the rock's pore space. Microbial 16S rDNA analysis suggests that there is presently a zonation of different bacterial groups within the redox band, and bacterial zonation played an important role in the concentration of Fe-oxyhydroxides at the redox front. These water-rock-microbe interactions can be considered analogous to the processes occurring in the redox fronts that would develop around geological repositories for radioactive waste. Once formed, the Fe-oxyhydroxides within such a front would be preserved even after reducing conditions resume following repository closure.

A heat source probe for measuring thermal conductivity in waste rock dumps

International Nuclear Information System (INIS)

Blackford, M.G.; Harries, J.R.

1985-10-01

The development and use of a heat source probe to measure the thermal conductivity of the material in a waste rock dump is described. The probe releases heat at a constant rate into the surrounding material and the resulting temperature rise is inversely related to the thermal conductivity. The probe was designed for use in holes in the dump which are lined with 50 mm i.d. polyethylene liners. The poor thermal contact between the probe and the liner and the unknown conductivity of the backfill material around the liner necessitated long heating and cooling times (>10 hours) to ensure that the thermal conductivity of the dump material was being measured. Temperature data acquired in the field were analysed by comparing them with temperatures calculated using a two-dimensional cylindrical model of the probe and surrounding material, and the heat transfer code HEATRAN

Characterization of steel grit recovered from ornamental rocks waste by magnetic separation

International Nuclear Information System (INIS)

Junca, E.; Telles, V.B.; Rodrigues, G.F.; Oliveira, J.R. de; Tenorio, J.A.S.

2010-01-01

The aim of this work is characterization of steel grit recovered from ornamental rock waste by magnetic separation. The magnetic separation was realized in three steps: first, using a high intensity wet magnetic separator, which used only the remaining magnetic field of equipment. In the second step, the magnetic material obtained in the first phase was subjected to a new manual magnetic separation using rare earth magnets. In a third step, magnetic material obtained with rare earth magnets was subjected to manual magnetic separation using ferrite magnets. After the magnetic separation, the material was sent to characterization which was obtained by chemical analysis, scanning electron microscopy, X-ray diffraction and size analysis. The size analysis showed that the concentrate range from 0,5 to 563,67 μm with 4 wt.% over 100 μm and content metallic iron of 93 wt%. (author)

THM-coupled modeling of selected processes in argillaceous rock relevant to rock mechanics; THM-Gekoppelte Modellierung ausgewaehlter gesteinsmechanisch relevanter Prozesse im Tongestein

Energy Technology Data Exchange (ETDEWEB)

Czaikowski, Oliver [Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) mbH, Braunschweig (Germany). Repository Safety Research Div.

2012-08-15

Scientific investigations in European countries other than Germany concentrate not only on granite formations (Switzerland, Sweden) but also on argillaceous rock formations (France, Switzerland, Belgium) to assess their suitability as host and barrier rock for the final storage of radioactive waste. In Germany, rock salt has been under thorough study as a host rock over the past few decades. According to a study by the German Federal Institute for Geosciences and Natural Resources, however, not only salt deposits but also argillaceous rock deposits are available at relevant depths and of extensions in space which make final storage of high-level radioactive waste basically possible in Germany. Equally qualified findings about the suitability/unsuitability of non-saline rock formations require fundamental studies to be conducted nationally because of the comparatively low level of knowledge. The article presents basic analyses of coupled mechanical and hydraulic properties of argillaceous rock formations as host rock for a repository. The interaction of various processes is explained on the basis of knowledge derived from laboratory studies, and open problems are deduced. For modeling coupled processes, a simplified analytical computation method is proposed and compared with the results of numerical simulations, and the limits to its application are outlined. (orig.)

Test procedures for salt rock

International Nuclear Information System (INIS)

Dusseault, M.B.

1985-01-01

Potash mining, salt mining, design of solution caverns in salt rocks, disposal of waste in salt repositories, and the use of granular halite backfill in underground salt rock mines are all mining activities which are practised or contemplated for the near future. Whatever the purpose, the need for high quality design parameters is evident. The authors have been testing salt rocks in the laboratory in a number of configurations for some time. Great care has been given to the quality of sample preparation and test methodology. This paper describes the methods, presents the elements of equipment design, and shows some typical results

Human error analysis project (HEAP) - The fourth pilot study: verbal data for analysis of operator performance

International Nuclear Information System (INIS)

Braarud, Per Oeyvind; Droeyvoldsmo, Asgeir; Hollnagel, Erik

1997-06-01

This report is the second report from the Pilot study No. 4 within the Human Error Analyses Project (HEAP). The overall objective of HEAP is to provide a better understanding and explicit modelling of how and why ''cognitive errors'' occur. This study investigated the contribution from different verbal data sources for analysis of control room operator's performance. Operator's concurrent verbal report, retrospective verbal report, and process expert's comments were compared for their contribution to an operator performance measure. This study looked into verbal protocols for single operator and for team. The main findings of the study were that all the three verbal data sources could be used to study performance. There was a relative high overlap between the data sources, but also a unique contribution from each source. There was a common pattern in the types of operator activities the data sources gave information about. The operator's concurrent protocol overall contained slightly more information on the operator's activities than the other two verbal sources. The study also showed that concurrent verbal protocol is feasible and useful for analysis of team's activities during a scenario. (author)

Evaluation of salt and mine rock disposal. Project No. 76-283

International Nuclear Information System (INIS)

1976-11-01

Studies are being performed on the isolation of nuclear waste in geological formations; this would entail constructing an underground mine in selected rock strata for waste storage. Rocks removed from the mine during construction must be either disposed of permanently or temporarily stored for later backfill into the mine. Several methods of storing or disposing of the mined rock are discussed in this report. The technical feasibility, cost, advantages and disadvantages of each method are presented and the ranking of methods based on currently available data is discussed. Salt, shale, granite, and limestone are covered

10 CFR 960.3-1-2 - Diversity of rock types.

Science.gov (United States)

2010-01-01

... 10 Energy 4 2010-01-01 2010-01-01 false Diversity of rock types. 960.3-1-2 Section 960.3-1-2... NUCLEAR WASTE REPOSITORY Implementation Guidelines § 960.3-1-2 Diversity of rock types. Consideration... sites for characterization shall have different types of host rock. ...

Nagra technical report 14-02, Geological basics - Dossier VI - Barrier properties of proposed host rock sediments and neighbouring rock

International Nuclear Information System (INIS)

Gautschi, A.; Deplazes, G.; Traber, D.; Marschall, P.; Mazurek, M.; Gimmi, T.; Maeder, U.

2014-01-01

This dossier is the sixth of a series of eight reports concerning the safety and technical aspects of locations for the disposal of radioactive wastes in Switzerland. It discusses the barrier properties of the proposed host rock sediments and neighbouring rock layers. The mineralogical composition of the host rocks are discussed as are their pore densities and hydrological properties. Diffusion aspects are discussed. The aquifer systems in the proposed depository areas and their classification are looked at. The barrier properties of the host rocks and those of neighbouring sediments are discussed. Finally, modelling concepts and parameters for the transport of radionuclides in the rocks are discussed

Creation and Plan of an Underground Geologic Radioactive Waste Isolation Facility at the Nizhnekansky Rock Massif in Russia

International Nuclear Information System (INIS)

Gupalo, T A; Kudinov, K G; Jardine, L J; Williams, J

2004-01-01

This joint geologic repository project in Russia was initiated in May 2002 between the United States (U.S.) International Science and Technology Center (ISTC) and the Federal State Unitary Enterprise ''All-Russian Research and Design Institute of Production Engineering'' (VNIPIPT). The project (ISTC Partner Project 2377) is funded by the U.S. Department of Energy Office of Civilian Radioactive Waste Management (DOE-RW) for a period of 2-1/2 years. ISTC project activities were integrated into other ongoing geologic repository site characterization activities near the Mining and Chemical Combine (MCC K-26) site. This allowed the more rapid development of a plan for an underground research laboratory, including underground design and layouts. It will not be possible to make a final choice between the extensively studied Verkhne-Itatski site or the Yeniseiski site for construction of the underground laboratory during the project time frame because additional data are needed. Several new sources of data will become available in the next few years to help select a final site. Studies will be conducted at the 1-km deep borehole at the Yeniseisky site where drilling started in 2004. And in 2007, after the scheduled shutdown of the last operating reactor at the MCC K-26 site, data will be collected from the rock massif as the gneiss rock cools, and the cool-down responses modeled. After the underground laboratory is constructed, the data collected and analyzed, this will provide the definitive evidence regarding the safety of the proposed geologic isolation facilities for radioactive wastes (RW). This data will be especially valuable because they will be collected at the same site where the wastes will be subsequently placed, rather than on hypothetical input data only. Including the operating costs for 10 to 15 years after construction, the cost estimate for the laboratory is $50M. With additional funding from non-ISTC sources, it will be possible to complete this

Evidence for the incorporation of lead into barite from waste rock pile materials

Energy Technology Data Exchange (ETDEWEB)

COURTIN-NOMADE, ALEXANDRA; SOUBRAND-COLIN, MARILYNE; MARCUS, MATTHEW A.; FAKRA, SIRINE .C

2008-01-21

Because Pb is one of the most toxic elements and is found as a major contaminant in mining environments, this study aims to identify the distribution of this element in host phases issued from the alteration of mine wastes. The sampling location was a former mine near Oakland, California (USA). This mine was once a source of sulfide minerals from which sulfuric acid was made. The material discussed in this paper was collected in iron hardpans that were formed within the waste rock pile resulting from the excavation work. In most contaminated environments (soils, mine waste), secondary metal-bearing phases arising from alteration processes are usually fine-grained (from 10 {micro}m to less than 1 {micro}m) and highly heterogeneous, requiring the use of micron-scale techniques. We performed micro-Raman spectroscopy, microscanning X-ray diffraction (SXRD), and microextended X-ray near edge spectroscopy (XANES) to determine the relationships between Pb and a Ba/Fe-rich host phase. Micro-Raman spectroscopy suggests that Pb is preferentially incorporated into barite rather than goethite. Results from micro-Raman experiments show the high sensitivity of this analytical tool to the incorporation of Pb into barite by being especially sensitive to the variations of the S-O bond and showing the characteristic bands due to the contribution of Pb. This association is confirmed and is well-illustrated by micro-SXRD mineral species maps showing the correlation between Pb and barite. Microfocused XANES indicates that Pb is present as Pb{sup 2+}, agreeing with the in situ physicochemical parameters.

Underground laboratories for rock mechanics before radioactive waste

International Nuclear Information System (INIS)

Duffaut, P.

1985-01-01

Many rock mechanics tests are performed in situ, most of them underground since 1936 at the Beni Bahdel dam. The chief tests for understanding the rock mass behaviour are deformability tests (plate test and pressure cavern test, including creep experiments) and strength tests (compression of a mine pillar, shear test on rock mass or joint). Influence of moisture, heat, cold and freeze are other fields of investigation which deserve underground laboratories. Behaviour of test galleries, either unsupported or with various kinds of support, often is studied along time, and along the work progression, tunnel face advance, enlargement or deepening of the cross section. The examples given here help to clarify the concept of underground laboratory in spite of its many different objectives. 38 refs.; 1 figure; 1 table

Radionuclide fixation mechanisms in rocks

International Nuclear Information System (INIS)

Nakashima, S.

1991-01-01

In the safety evaluation of the radioactive waste disposal in geological environment, the mass balance equation for radionuclide migration is given. The sorption of radionuclides by geological formations is conventionally represented by the retardation of the radionuclides as compared with water movement. In order to quantify the sorption of radionuclides by rocks and sediments, the distribution ratio is used. In order to study quantitatively the long term behavior of waste radionuclides in geological environment, besides the distribution ratio concept in short term, slower radionuclide retention reaction involving mineral transformation should be considered. The development of microspectroscopic method for long term reaction path modeling, the behavior of iron during granite and water interaction, the reduction precipitation of radionuclides, radionuclide migration pathways, and the representative scheme of radionuclide migration and fixation in rocks are discussed. (K.I.)

Sulfide oxidation and the natural attenuation of arsenic and trace metals in the waste rocks of the abandoned Seobo tungsten mine, Korea

International Nuclear Information System (INIS)

Lee, Pyeong-koo; Kang, Min-Ju; Choi, Sang-Hoon; Touray, Jean-Claude

2005-01-01

Mineralogical examinations were performed to characterize the formation of secondary minerals and natural removal process of dissolved As and trace metals (Pb, Zn and Cu) from sulfide oxidation. Laboratory-based leaching tests were also conducted to determine whether the concentrations of As and trace metals in the leachates from waste-rock materials and contaminated soil could be affected by the presence acids such as acid rainwater or acid mine drainage. Waste-rock materials and contaminated soil were compared by 4-day leaching tests using HNO 3 solutions of increasing acidity (0.00001-0.1mole/L). Mineralogical studies of the waste rocks confirmed the presence of Fe-(oxy)hydroxides (e.g. goethite), jarosite, elemental S, Fe-sulfates, amorphous Fe-As phases, anglesite and covellite as secondary minerals. These secondary minerals act as mineralogical scavengers of dissolved trace metals, SO 4 2- and acidity released by sulfide oxidation. Arsenic was attenuated by the adsorption on Fe-(oxy)hydroxides and/or the formation of an amorphous Fe-As phase, with a Fe/As ratio=1 (maybe scorodite: FeAsO 4 .2H 2 O). Electron probe microanalyses data showed that the Fe-(oxy)hydroxides had high concentrations of Pb (up to 21wt%), with appreciable amounts of As (up to 7.7wt%), Zn (up to 4.6wt%) and Cu (up to 2.5wt%) indicating that dissolved metals were co-precipitated and adsorbed onto Fe-(oxy)hydroxides, Fe(Mn)-hydroxides and Fe-sulfates. The results of the leaching experiments within the pH-range 3.5-5.0 indicated that acidic rainstorms may leach minor amounts of Pb (ca. 1.7-4.0% of total), Zn (ca. 0.8-2.2% of total), Cu (ca. 0.0-0.2% of total) and As (ca. 0.02-0.1% of total) from waste rocks, including the dissolution of soluble secondary minerals previously formed during prolonged dry periods, while dissolution of these elements was negligible from the contaminated soil. In the pH-range 1.0-3.0, the leaching of Pb (ca. 2.4-31% of total) and As (ca. 0.1-5.8% of total) from

Measurements and modeling of gas fluxes in unsaturated mine waste materials

Energy Technology Data Exchange (ETDEWEB)

Kabwe, L.K.

2008-07-01

A technique known as dynamic closed chamber (DDC) was recently developed to measure carbon dioxide (CO{sub 2}) fluxes from the soil surface to the atmosphere. The field application of the DCC was investigated in this thesis with a particular focus on quantifying reaction rates in 2 waste-rock piles at the Key Lake uranium mine in northern Saskatchewan. The dominant geochemical reactions in both waste-rock piles were not typical of acid rock drainage (ARD) waste-rock piles. The CO{sub 2} fluxes measured in this study occur in the organic material underlying the waste rocks. The study provided a complete suite of measurements needed to characterize spatial distribution of CO{sub 2} fluxes on larger-scale studies of waste-rock piles. In comparison to other CO{sub 2} flux measuring techniques, the DCC method accurately quantified field soil respiration and had an added advantage in terms of speed and repeatability. The DCC was also used to investigate CO{sub 2} fluxes under the climatic variables that affect soil water content in waste-rock piles. A simple model for predicting the effects of soil water content on CO{sub 2} diffusion coefficient and concentration profiles was developed and verified. It was concluded that the DCC method is suitable for field applications to quantify CO{sub 2} fluxes and to characterize the spatial and temporal dynamics of CO{sub 2} fluxes from unsaturated C-horizon soils and waste-rock piles.

Mechanisms of hydrothermal alteration in a granitic rock. Consequences for high-level radioactive waste disposal

International Nuclear Information System (INIS)

Parneix, J.C.

1987-06-01

The study of hydrothermal alteration in the Auriat granitic rock (France, Massif-Central) has evidenced three main events: - a pervasive chloritisation of biotites in some parts of the drill-core, - an alteration localized around subvertical cracks and superimposed on previously chloritized or unaltered granite, - an alteration localized around subhorizontal cracks cross-cutting the preceding ones. The second type of alteration, produced by a geothermal system, gives the most interesting results to be applied to the nuclear radwaste disposal problem. Among primary minerals of granite, only biotite (or chlorite) and oligoclase are intensively altered. Therefore, the chemical composition of these minerals induces the nature of secondary parageneses. These, associated to the subvertical cracks network, indicate a thermal gradient of 150 C/Km. The geochemical code has allowed to corroborate that the thermal gradient was responsible for the occurrence of different parageneses with depth. Moreover, it was shown that the variable mineralogy around cracks was due to a thermal profile established at equilibrium between the rock and the fluid. Therefore, the extent of the alteration was proportional to the thermal power of the fluid. A dissolution and next a precipitation phase of new minerals characterize hydrothermal alteration, which is due to the thermal power emitted by radioactive waste and linked with the evolution of temperature during time. This alteration provokes two favourable events to storage: decrease of rock porosity and increase of sorption capacity [fr

Rock engineering applications, 1991

International Nuclear Information System (INIS)

Franklin, J.A.; Dusseault, M.B.

1991-01-01

This book demonstrates how to apply the theories and principles of rock engineering to actual engineering and construction tasks. It features insights on geology for mining and tunnelling applications. It is practical resource that focuses on the latest technological innovation and examines up-to-date procedures used by engineers for coping with complex rock conditions. The authors also discuss question related to underground space, from design approaches to underground housing and storage. And they cover the monitoring of storage caverns for liquid and gaseous products or toxic and radioactive wastes

Fe, Cr, Ni, Cu, Mg, Al, Ti, and S contents in plants and soil of heaps of nickel smelting works

Energy Technology Data Exchange (ETDEWEB)

Banasova, V; Hajduk, J

1977-01-01

The writers established the Fe, Ce, Cr, Ni, Ca, Mg, Al, Ti and S contents in the neopedon of heaps piling up from processing of nickel ore as well as in the plants: Cardaria draba, Salsola cali, Agropyrum repens, Bromus erectus, Calamagrostis epigeios, Cynodon dactylon and Matricaria inodora, growing on such heaps. Ca, Mg and S contents were found to be higher in dicotyledons and Fe, Al, Ti, Ni and Cr contents higher in monocotyledons. The analyzed dicotyledons appeared to be concentrators of Ca and S. Highest Fe, Al, Ti, Ni and Cr contents were found in individuals of the species Agropyrum repens. The neopedon as well as the plants had extraordinarily high Cr concentrations. The species Salsola cali has been found to possess an unusually higher affinity to the dump substrate after processing of nickel ore and to be a concentrator of Mg. 16 references, 1 table.

Shaft sealing concepts for high-level radioactive waste repositories based on the host-rock options rock salt and clay stone; Schachtverschlusskonzepte fuer zukuenftige Endlager fuer hochradioaktive Abfaelle fuer die Wirtsgesteinsoptionen Steinsalz und Ton

Energy Technology Data Exchange (ETDEWEB)

Kudla, Wolfram; Gruner, Matthias [TU Bergakademie Freiberg (Germany). Inst. fuer Erdbau und Spezialtiefbau; Herold, Philipp; Jobmann, Michael [DBE Technology GmbH, Peine (Germany)

2015-07-01

Unlike the shaft barriers used for the dry preservation of former mine workings and underground storage sites, shaft seals designed for radioactive-waste repositories must also fulfil additional requirements associated with the design diversity of the sealing system. This diversity makes use of the simple redundancy principle in order to prevent the proliferation of defects. In practice this means combining several sealing elements made from different materials or from materials with different properties. The R and D project, Shaft sealing systems for final repositories for high-level radioactive waste (ELSA) - phase 2: concept design for shaft seals and testing of the functional elements of shaft seals', which was funded by the Federal Ministry for Economic Affairs and Energy (BMWi), set out to investigate potential sealing elements for the two host-rock options rock salt and mudstone. This paper combines the text that the authors presented at the First International Freiberg Shaft Colloquium held at the Freiberg University of Mining and Technology on 01.10.2014 with a presentation on the sealing elements that were investigated as part of the R and D project.

Diffusion in the matrix of granitic rock

International Nuclear Information System (INIS)

Birgersson, L.; Neretnieks, I.

1982-07-01

A migration experiment in the rock matrix is presented. The experiment has been carried out in undisturbed rock, that is rock under its natural stress environment. Since the experiment was performed at the 360 m-level (in the Stripa mine), the rock had nearly the same conditions as the rock surrounding a nuclear waste storage. The results show that all three tracers (Uranine, Cr-EDTA and I - ) have passed the disturbed zone from the injection hole and migrated into undisturbed rock. At the distance of 11 cm from the injection hole 5-10 percent of the injection concentration was found. The results also indicate that the tracer have passed through fissure filling material. These results indicate that it is possible for tracers (and therefore radionuclides) to migrate from a fissure, through fissure filling material, and into the undisturbed rock matrix. (Authors)

Rapid formation of rock armour for soil - rock fragment mixture during simulated rainfall

Science.gov (United States)

Poultney, E.; McGrath, G. S.; Hinz, C.

2009-04-01

Preventing erosion is an important issue in disturbed semi-arid and arid landscapes. This is in particular of highest importance for mining companies while undertaking land rehabilitation. An onsite investigation of the impact of surface rock fragments on erosion was conducted at Telfer goldmine in the Great Sandy Desert, Western Australia. The study site is a waste rock dump designed to mimic the concave slope of a natural mesa to both discourage erosion and blend in with its natural surroundings. Four treatments were used to construct the slope: two are topsoil mixed with rock fragments, and two are unmixed topsoil. A field study investigating erosion rills, particle size distribution, rock fragment coverage surface roughness and vegetation was carried out to determine changes down and across slope. The treatments constructed by mixing topsoil and rock fragments are more stable and show rock fragment distributions that more closely resemble patterns found on natural mesas surrounding Telfer. A controlled study using trays of topsoil mixed with rock fragment volumes of 50%, 60%, 70% and 80% were used to investigate how varying mixtures of rock fragments and topsoil erode using rainfall intensities between 20 and 100 mm h-1. Two runs of 25 minutes each were used to assess the temporal evolution of rock armouring. Surface coverage results converged for the 50%, 60% and 70% mixtures after the first run to coverage of about 90%, suggesting that fine sediment proportion does not affect rate and degree of rock armouring.

Fine-grained sheet silicate rocks

International Nuclear Information System (INIS)

Weaver, C.E.

1977-09-01

Considerable interest has been shown in the possibility of using shales as repositories for radioactive waste and a variety of other waste products, and it appears that over the next few years much money and effort will be expended to investigate and test a wide variety of shales. If shales are to be studied in detail by a large number of investigators, it is important that all concerned have the same concept of what constitutes a shale. The term shale and other terms for fine-grained rocks have been used for many years and have been continually redefined. Most definitions predate the development of modern instrumentation and are based on field observations and intuition; however, the main problem is the diversity of definitions. An attempt is made here to develop a simple, rational classification of fine-grained sediments, and it is hoped that this classification will eliminate some of the present ambiguity. In order that the classification be pertinent, mineral composition and textural data were compiled and evaluated. The data on unconsolidated and consolidated sediments were contrasted and the effects of burial diagenesis assessed. It was found necessary to introduce a new term, physil, to describe all sheet silicate minerals. In contrast to the term clay mineral, the term physil has no size connotation. A simple classification is proposed that is based on the percentage of physils and grain size. In Part II the fine-grained physil rocks are classified on the basis of physil type, non-physil minerals, and texture. Formations are listed which have the mineral and textural characteristics of the most important rock types volumetrically. Selected rock types, and the formations in which they can be found, are recommended for laboratory study to determine their suitability for the storage of high-level radioactive waste

Comparison of the intermediate storage periods and areas required for final storage of high-level radioactive waste and spent fuel in various types of host rock

International Nuclear Information System (INIS)

Mueller-Hoeppe, N.; Lerch, C.; Jobmann, M.; Filbert, W.

2005-01-01

The present new version of the German concept for radioactive waste and spent fuel management is based on the assumption that a repository for high-level waste and spent fuel will not be required until 2030. One reason frequently given for this date is the intermediate storage period of at least forty years to allow the very high initial heat generation to decay. However, calculations performed by the authors have shown that the minimum intermediate storage period for a repository in rock salt is only between four and nineteen years, depending on the final storage concept and the load of the waste package. In clay as a host rock, the minimum intermediate storage times were calculated to be between 31 and 142 years; the same time spans are expected to apply to final storage in magmatic rock, such as granite. The maximum permissible loads of a container holding spent fuel in salt are many times those in clay and granite, respectively. It was also seen that the area requirement for final storage of the same waste structures is roughly a factor of ten higher in clay than in salt. The differences between granite and salt are similar. The reasons for these grave differences, on the one hand, are the better thermal conductivity of salt and, on the other hand, the better heat tolerance of the crushed salt used as backfill material compared to that of bentonite used in the clay and granite concepts. While salt will allow temperatures of up to 200 C, the maximum temperature in bentonite is limited to 100 C. (orig.)

Monitoring of a burning conical heap by combining topographical mapping with infrared thermography

International Nuclear Information System (INIS)

Carpentier, O.; Antczak, E.; Defer, D.; Duthoit, B.

2003-01-01

One of the most used method for monitoring a slag heap is the air infrared thermography. Even if it permit to survey a large area and provide a well contrasted display of dangerous areas, this method is expensive, perturbed by atmospheric conditions and cannot offer an accurate localization of defects. In order to mitigate this disadvantage, the LAMH, in association with Groupe Charbonnages de France, set up a method based on topographic and infrared thermographic cross reading which is more accurate, less expensive and, in a near future, will permit a monitoring of combustion reaction. (authors)

National waste terminal storage program. Progress report, September 1977

International Nuclear Information System (INIS)

Asher, J.M.

1977-01-01

Project reports are given of the following studies: USGS Water Resources Division study of Louisiana salt domes; Northeast Texas Salt Dome Basin study; salt-dome hydrology in Mississippi; volcanic rocks; crystalline rocks; Paradox Basin; geologic studies at the Nevada Test Site; heat transfer/thermal analysis; waste/rock interaction; rock mechanics; borehole plugging; safety and reliability; shale and clay mineral studies; conceptual design of NWTS repositories; waste container studies; transportation/logistics study; and environmental study

Waste package designs for disposal of high-level waste in salt formations

International Nuclear Information System (INIS)

Basham, S.J. Jr.; Carr, J.A.

1984-01-01

In the United States of America the selected method for disposal of radioactive waste is mined repositories located in suitable geohydrological settings. Currently four types of host rocks are under consideration: tuff, basalt, crystalline rock and salt. Development of waste package designs for incorporation in mined salt repositories is discussed. The three pertinent high-level waste forms are: spent fuel, as disassembled and close-packed fuel pins in a mild steel canister; commercial high-level waste (CHLW), as borosilicate glass in stainless-steel canisters; defence high-level waste (DHLW), as borosilicate glass in stainless-steel canisters. The canisters are production and handling items only. They have no planned long-term isolation function. Each waste form requires a different approach in package design. However, the general geometry and the materials of the three designs are identical. The selected waste package design is an overpack of low carbon steel with a welded closure. This container surrounds the waste forms. Studies to better define brine quantity and composition, radiation effects on the salt and brines, long-term corrosion behaviour of the low carbon steel, and the leaching behaviour of the spent fuel and borosilicate glass waste forms are continuing. (author)

Development of soda-lime glasses from ornamental rock wastes

International Nuclear Information System (INIS)

Babisk, Michelle Pereira

2009-01-01

During the ornamental rocks production, among other steps, one saw the rock blocks in order to transform them into semi-finished plates. In this step, expressive amounts of residues are generated, which are not properly discharged in nature, without any programmed utilization. The residues of silicide rocks present, in their compositions, oxides which are raw materials employed to fabricate soda-lime type glasses (containing SiO_2, Al_2O_3, CaO, Na_2O and K_2O). On the other hand the residues of carbonatic rocks are constituted of glass net modifier oxides, like CaO and MgO. In this work it was developed four types of soda-lime glasses using ornamental rock residues, where the glasses compositions were adjusted by adding sand, as silica source, as well as sodium and calcium carbonates as sources of Na_2O and CaO, respectively. The obtained glasses were characterized by means of Archimed's method for densities measurements, microstructure by using optical and electronic microscopy, phases by means of X-ray diffraction (XRD), hardness by Vickers indentation, spectroscopy (UV/VIS), and hydrolytic resistance according to ISO 719. The XRD analyses confirmed the compositions total vitrification, where the greened aspect of the samples was due to the presence of the iron oxides. The produced glasses properties were compared with those of commercial glasses aiming their industrial employment. The main difference between the produced glasses and those commercials varied primarily regarding the amount of carbonates incorporated. The results showed that the ornamental rocks residues may be used as raw materials for glasses fabrication, and they found a useful economic destination rather than discharge which promotes undesirable environmental impact. (author)

Coupled heat and groundwater flow in porous rock

International Nuclear Information System (INIS)

Rae, J.; Robinson, P.C.; Wickens, L.M.

1983-01-01

There are a number of technical areas where coupled heat and flow problems occur for water in porous rock. The area of most interest to the authors has been the possible disposal underground of high-level radioactive waste. High-level waste can emit enough heat to drive significant flows by buoyancy effects and groundwater flow is expected to be the chief transport process for solute leached from such a repository. The possible disposal of radioactive waste under the seabed raises many similar questions and needs similar techniques to find answers. Other areas where related questions arise are the storage and retrieval of hot water in underground reservoirs, the attempts to extract useful geothermal energy by pumping water into fracture systems in hot rock and in certain thermal techniques for persuading oil to flow in tight reservoirs. The authors address questions in a rather general way and give examples which lie more in the area of waste disposal

GRS' research on clay rock in the Mont Terri underground laboratory

Energy Technology Data Exchange (ETDEWEB)

Wieczorek, Klaus; Czaikowski, Oliver [Gesellschaft fuer Anlagen- und Reaktorsicherheit gGmbH, Braunschweig (Germany)

2016-07-15

For constructing a nuclear waste repository and for ensuring the safety requirements are met over very long time periods, thorough knowledge about the safety-relevant processes occurring in the coupled system of waste containers, engineered barriers, and the host rock is indispensable. For respectively targeted research work, the Mont Terri rock laboratory is a unique facility where repository research is performed in a clay rock environment. It is run by 16 international partners, and a great variety of questions are investigated. Some of the work which GRS as one of the Mont Terri partners is involved in is presented in this article. The focus is on thermal, hydraulic and mechanical behaviour of host rock and/or engineered barriers.

MCDIRC: A model to estimate creep produced by microcracking around a shaft in intact rock

International Nuclear Information System (INIS)

Wilkins, B.J.S.; Rigby, G.L.

1989-12-01

Atomic Energy of Canada Limited (AECL) is studying the concept of disposing of nuclear fuel waste in a vault in plutonic rock. Models are being developed to predict the mechanical behaviour of the rock in response to excavation and heat from the waste. The dominant mechanism of deformation at temperatures below 150 degrees C is microcracking, which results in rock creep and a decrease in rock strength. A model has been constructed to consider the perturbation of the stress state of intact rock by a vertical cylindrical opening. Slow crack-growth data are used to estimate time-dependent changes in rock strength, from which the movement (creep) of the opening wall and radial strain in the rock mass can be estimated

Case study: remediation of a former uranium mining/processing site in Hungary

International Nuclear Information System (INIS)

Csovari, M. et al.

2004-01-01

The Hungarian uranium mining activities near Pecs lasted from 1958 to 1997. Approximately 46 Mt of rock were mined, from which 18.8 Mt of upgraded ore were processed. Some ore had been exported prior to the construction of the processing plant at the site. Remediation of the former uranium-related industrial sites is being carried out by the Mecsek Ore Environment Ltd. and started in the 1990s. Today the former mines and their surroundings are rehabilitated, former heap piles and a number of smaller waste rock piles have been relocated to a more protected area (waste rock pile N 3). Ongoing core remediation activities are directed to the remediation of the tailings ponds, and also water treatment issues are most important. Three water treatment facilities are currently in operation: a mine water treatment system with the objective to remove uranium and gain a marketable by-product; a pump-and-treat system to restore the groundwater quality in the vicinity of the tailing ponds; a pilot-scale, experimental passive in-situ groundwater treatment system to avoid migration of uranium contaminated groundwater. Refs. 5 (author)

Reference stratigraphy and rock properties for the Waste Isolation Pilot Plant (WIPP) project

International Nuclear Information System (INIS)

Krieg, R.D.

1984-01-01

A stratigraphic description of the country rock near the working horizon at the Waste Isolation Pilot Plant (WIPP) is presented along with a set of mechanical and thermal properties of materials involved. Data from 41 cores and shafts are examined. The entire stratigraphic section is found to vary in elevation in a regular manner, but individual layer thicknesses and relative separation between layers are found to have no statistically significant variation over the one mile north to south extent of the working horizon. The stratigraphic description is taken to be relative to the local elevation of Anhydrite b. The material properties have been updated slightly from those in the July 1981 Reference Stratigraphy. This reference stratigraphy/properties document is intended primarily for use in thermal/structural analyses. This document supercedes the July 1981 stratigraphy/properties document. 31 references, 7 figures

Physical and mechanical properties of degraded waste surrogate material

International Nuclear Information System (INIS)

Hansen, F.D.; Mellegard, K.D.

1998-03-01

This paper discusses rock mechanics testing of surrogate materials to provide failure criteria for compacted, degraded nuclear waste. This daunting proposition was approached by first assembling all known parameters such as the initial waste inventory and rock mechanics response of the underground setting after the waste is stored. Conservative assumptions allowing for extensive degradation processes helped quantify the lowest possible strength conditions of the future state of the waste. In the larger conceptual setting, computations involve degraded waste behavior in transient pressure gradients as gas exits the waste horizon into a wellbore. Therefore, a defensible evaluation of tensile strength is paramount for successful analyses and intentionally provided maximal failed volumes. The very conservative approach assumes rampant degradation to define waste surrogate composition. Specimens prepared from derivative degradation product were consolidated into simple geometries for rock mechanics testing. Tensile strength thus derived helped convince a skeptical peer review panel that drilling into the Waste Isolation Pilot Plant (WIPP) would not likely expel appreciable solids via the drill string

National survey of crystalline rocks and recommendations of regions to be explored for high-level radioactive waste repository sites

International Nuclear Information System (INIS)

Smedes, H.W.

1983-04-01

A reconnaissance of the geological literature on large regions of exposed crystalline rocks in the United States provides the basis for evaluating if any of those regions warrant further exploration toward identifying potential sites for development of a high-level radioactive waste repository. The reconnaissance does not serve as a detailed evaluation of regions or of any smaller subunits within the regions. Site performance criteria were selected and applied insofar as a national data base exists, and guidelines were adopted that relate the data to those criteria. The criteria include consideration of size, vertical movements, faulting, earthquakes, seismically induced ground motion, Quaternary volcanic rocks, mineral deposits, high-temperature convective ground-water systems, hydraulic gradients, and erosion. Brief summaries of each major region of exposed crystalline rock, and national maps of relevant data provided the means for applying the guidelines and for recommending regions for further study. It is concluded that there is a reasonable likelihood that geologically suitable repository sites exist in each of the major regions of crystalline rocks. The recommendation is made that further studies first be conducted of the Lake Superior, Northern Appalachian and Adirondack, and the Southern Appalachian Regions. It is believed that those regions could be explored more effectively and suitable sites probably could be found, characterized, verified, and licensed more readily there than in the other regions

National survey of crystalline rocks and recommendations of regions to be explored for high-level radioactive waste repository sites

Energy Technology Data Exchange (ETDEWEB)

Smedes, H.W.

1983-04-01

A reconnaissance of the geological literature on large regions of exposed crystalline rocks in the United States provides the basis for evaluating if any of those regions warrant further exploration toward identifying potential sites for development of a high-level radioactive waste repository. The reconnaissance does not serve as a detailed evaluation of regions or of any smaller subunits within the regions. Site performance criteria were selected and applied insofar as a national data base exists, and guidelines were adopted that relate the data to those criteria. The criteria include consideration of size, vertical movements, faulting, earthquakes, seismically induced ground motion, Quaternary volcanic rocks, mineral deposits, high-temperature convective ground-water systems, hydraulic gradients, and erosion. Brief summaries of each major region of exposed crystalline rock, and national maps of relevant data provided the means for applying the guidelines and for recommending regions for further study. It is concluded that there is a reasonable likelihood that geologically suitable repository sites exist in each of the major regions of crystalline rocks. The recommendation is made that further studies first be conducted of the Lake Superior, Northern Appalachian and Adirondack, and the Southern Appalachian Regions. It is believed that those regions could be explored more effectively and suitable sites probably could be found, characterized, verified, and licensed more readily there than in the other regions.

Proceedings of the scientific visit on crystalline rock repository development.

Energy Technology Data Exchange (ETDEWEB)

Mariner, Paul E.; Hardin, Ernest L.; Miksova, Jitka [RAWRA, Czech Republic

2013-02-01

A scientific visit on Crystalline Rock Repository Development was held in the Czech Republic on September 24-27, 2012. The visit was hosted by the Czech Radioactive Waste Repository Authority (RAWRA), co-hosted by Sandia National Laboratories (SNL), and supported by the International Atomic Energy Agency (IAEA). The purpose of the visit was to promote technical information exchange between participants from countries engaged in the investigation and exploration of crystalline rock for the eventual construction of nuclear waste repositories. The visit was designed especially for participants of countries that have recently commenced (or recommenced) national repository programmes in crystalline host rock formations. Discussion topics included repository programme development, site screening and selection, site characterization, disposal concepts in crystalline host rock, regulatory frameworks, and safety assessment methodology. Interest was surveyed in establishing a %E2%80%9Cclub,%E2%80%9D the mission of which would be to identify and address the various technical challenges that confront the disposal of radioactive waste in crystalline rock environments. The idea of a second scientific visit to be held one year later in another host country received popular support. The visit concluded with a trip to the countryside south of Prague where participants were treated to a tour of the laboratory and underground facilities of the Josef Regional Underground Research Centre.

Site investigations, design, construction, operation, shutdown and surveillance of repositories for low- and intermediate-level radioactive wastes in rock cavities

International Nuclear Information System (INIS)

1984-01-01

The report provides an overview and technical guidelines for considerations and for activities to be undertaken for safety assessment, site investigations, design, construction, operation, shutdown and surveillance of repositories for the disposal of low- and intermediate-level radioactive wastes in rock cavities. A generalized sequence of investigations is introduced which proceeds through region and site selection to the stage where the site is confirmed by detailed geoscientific investigations as being suitable for a waste repository. The different procedures and somewhat specific investigative needs with respect to existing mines are dealt with separately. General design, as well as specific requirements with respect to the different stages of design and construction, are dealt with. A review of activities related to the operational and post-operational stages of repositories in rock cavities is presented. The report describes in general terms the procedures related to different stages of disposal operation; also the conditions for shutdown together with essential shutdown and sealing activities and the related safety assessment requirements. Guidance is also given on the surveillance programme which will allow for inspection, testing, maintenance and security of a disposal facility during the operational phase, as well as for the post-operational stage for periods determined as necessary by the national authorities

Accumulated energy determination in salts rocks irradiated by means of thermoluminescence techniques: application to the high level radioactive wastes repositories analysis

International Nuclear Information System (INIS)

Dies, J.; Ortega. J.; Tarrasa. F.; Cuevas, C.

1995-01-01

The report summarizes the study carried out to develop the radiation effects on salt rocks in order to repository the high level radioactive wastes. The study is structured into 3 main aspects: 1.- Analysis of irradiation experiences in Haw project of Pet ten reactor. 2.- Irradiation of salt sample of CESAR industrial irradiator. 3.- Correlation study between the accumulated energy, termoluminescence answer and the defect concentration

Expected environment for waste packages in a salt repository

International Nuclear Information System (INIS)

Pederson, L.R.; Clark, D.E.; Hodges, F.N.; McVay, G.L.; Rai, D.

1983-01-01

This paper discusses results of recent efforts to define the very near-field (within approximately 2 m) environmental conditions to which waste packages will be exposed in a salt repository. These conditions must be considered in the experimental design for waste package materials testing, which includes corrosion of barrier materials and leaching of waste forms. Site-specific brine compositions have been determined, and standard brine compositions have been selected for testing purposes. Actual brine compositions will vary depending on origin, temperature, irradiation history, and contact with irradiated rock salt. Results of irradiating rock salt, synthetic brines, rock salt/brine mixtures, and reactions of irradiated rock salt with brine solutions are reported. 38 references, 3 figures, 2 tables

Compressible fluid flow through rocks of variable permeability

International Nuclear Information System (INIS)

Lin, W.

1977-01-01

The effectiveness of course-grained igneous rocks as shelters for burying radioactive waste can be assessed by determining the rock permeabilities at their in situ pressures and stresses. Analytical and numerical methods were used to solve differential equations of one-dimensional fluid flow through rocks with permeabilities from 10 4 to 1 nD. In these calculations, upstream and downstream reservoir volumes of 5, 50, and 500 cm 3 were used. The optimal size combinations of the two reservoirs were determined for measurements of permeability, stress, strain, acoustic velocity, and electrical conductivity on low-porosity, coarse-grained igneous rocks

Clay club catalogue of characteristics of argillaceous rocks

International Nuclear Information System (INIS)

2005-01-01

The OECD/NEA Working Group on the Characterisation, the Understanding and the Performance of Argillaceous Rocks as Repository Host Formations, namely the Clay Club, examines the various argillaceous rocks that are being considered for the deep geological disposal of radioactive waste, i.e. from plastic, soft, poorly indurated clays to brittle, hard mud-stones or shales. The Clay Club considered it necessary and timely to provide a catalogue to gather in a structured way the key geo-scientific characteristics of the various argillaceous formations that are - or were - studied in NEA member countries with regard to radioactive waste disposal. The present catalogue represents the outcomes of this Clay Club initiative. (author)

Evaluation of possible host rocks for China's high level radioactive waste repository and the progress in site characterization at the Beishan potential site in NW China's Gansu province

International Nuclear Information System (INIS)

Wang Ju; Jin Yuanxin; Chen Zhangru; Chen Weiming; Wang Wenguang

2000-01-01

Evaluation of possible host rocks for China's high level radioactive waste repository is summarized in this paper. The distribution and characteristics of granite, tuff, clay stone, salt and loess in China are described, while maps showing the distribution of host rocks are presented. Because of the wide distribution, large scale, good heat conductivity and suitable mechanical properties, granite is considered as the most potential host rock. Some granite bodies distributed in NW China, SW China, South China and Inner Mongolia have been selected as potential areas. Detailed site characterization at Beishan area, Gansu Province NW China is in progress

Methods and results of the investigation of the thermomechanical behaviour of rock salt with regard to the final disposal of high-level radioactive wastes

International Nuclear Information System (INIS)

Wieczorek, K.; Klarr, K.

1993-01-01

This report summarizes the knowledge about thermal and mechanical behaviour of rock salt that has been accumulated by various R and D institutions in Germany from laboratory and in situ investigations. An important objective is to give a comprehensive overview of the investigation methods and instruments available and to discuss these methods and instruments with regard to their applicability and reliability for the investigation of the thermomechanical effects of high level radioactive waste emplacement in rock salt formations. The report is focused on the activities of the GSF-Institut fur Tieflagerung in the Asse mine regarding the disposal of high and intermediate level radioactive waste during the last decades. The design and the results of the most important in situ experiments are presented and discussed in detail. The results are compared to model calculations in order to evaluate the reliability of both the measurements and the calculation results. The relevance of the results for the situation in Spain is discussed in a separate chapter. As the investigations in Germany have been performed in domal salt, while the Spanish concept is based on waste disposal in bedded salt, significant differences in the thermomechanical behaviour cannot be excluded. The investigation methods, however, will be applicable. (Author)

Compost production from municipal wastes of Canadian mining towns

International Nuclear Information System (INIS)

Jongejan, A.

1983-01-01

A summary of results of experiements on composting mumicipal wastes, and an overview of a type of composting process that could be used in small Canadian mining towns are given. The process is a means of waste disposal designed to produce compost. Compost can be used for the revegetation of mine-mill tailings as its sorptive properties complement the chemical action of inorganic fertilizers. The possibility of using compost instead of peat in water pollution-abatement processes can be considered. Difficulties that can be expected if a windrow composting process is continued during the low ambient-temperatures of Canadian winters can be avoided by storing the garbage-sewage mixture as hydraulically-compacted briquettes. Degradation of the briquettes takes place during mild-temperature periods without producing the foul odors of heaped garbage. A tentative plan for composting plant is presented as an illustration of the applicatin of the experimental results in a practical process. Because the process is a means of waste disposal, costs have to be divided between the municipality and the mining industry

The disposal of Canada's nuclear fuel waste: a study of postclosure safety of in-room emplacement of used CANDU fuel in copper containers in permeable plutonic rock volume 1: summary

International Nuclear Information System (INIS)

Wikjord, A.G.; Baumgartner, P.; Johnson, L.H.; Stanchell, F.W.; Zach, R.; Goodwin, B.W.

1996-06-01

The concept for disposal of Canada's nuclear fuel waste involves isolating the waste in corrosion-resistant containers emplaced and sealed within a vault at a depth of 500 to 1000 m in plutonic rock of the Canadian Shield. The case for the acceptability of the concept as a means of safely disposing of Canada's nuclear fuel waste is presented in an Environmental Impact Statement (EIS) The disposal concept permits a choice of methods, materials, site locations and designs. The EIS presents a case study of the long-term (i.e., postclosure) performance of a hypothetical implementation of the concept, referred to in this report as the reference disposal system. The reference disposal system is based on borehole emplacement of used CANDU fuel in Grade-2 titanium alloy containers in low-permeability, sparsely fractured plutonic rock of the Canadian Shield. We evaluate the long-term performance of another hypothetical implementation of the concept based on in-room emplacement of used CANDU fuel in copper containers in permeable plutonic rock. The geological characteristics of the geosphere assumed for this study result in short groundwater travel times from the disposal vault to the surface. In the present study, the principal barrier to the movement of contaminants is the long-lasting copper container. We show that the long-lasting container can effectively compensate for a permeable host rock which results in an unfavourable groundwater flow condition. These studies illustrate the flexibility of AECL's disposal concept to take advantage of the retention, delay, dispersion, dilution and radioactive decay of contaminants in a system of natural barriers provided by the geosphere and hydrosphere and of engineered barriers provided by the waste form, container, buffer, backfills, other vault seals and grouts. In an actual implementation, the engineered system would be designed for the geological conditions encountered at the host site. 34 refs., 2 tabs., 11 figs

Deep fracturation of granitic rock mass

International Nuclear Information System (INIS)

Bles, J.L.; Blanchin, R.; Bonijoly, D.; Dutartre, P.; Feybesse, J.L.; Gros, Y.; Landry, J.; Martin, P.

1986-01-01

This documentary study realized with the financial support of the European Communities and the CEA aims at the utilization of available data for the understanding of the evolution of natural fractures in granitic rocks from the surface to deep underground, in various feasibility studies dealing with radioactive wastes disposal. The Mont Blanc road tunnel, the EDF Arc-Isere gallerie, the Auriat deep borehole and the Pyrenean rock mass of Bassies are studied. In this study are more particularly analyzed the relationship between small fractures and large faults, evolution with depth of fracture density and direction, consequences of rock decompression and relationship between fracturation and groundwater [fr

Measurement of diffusive properties of intact rock

Energy Technology Data Exchange (ETDEWEB)

Harvey, K B

1996-12-01

In the Postclosure Assessment of a Reference System for the Disposal of Canada`s Nuclear Fuel Waste (Goodwin et al. 1994) the disposal vault is assumed to be surrounded by a zone of intact rock, referred to as the `exclusion zone.` A sensitivity analysis of the relative effectiveness of the several engineered and natural barriers that contribute to the safety of the reference disposal system has shown that this zone of intact rock is the most effective of these barriers to the movement of radionuclides through the reference system. Peer review of the geosphere model used in the case study for the EIS (Environmental Impact Statement) of the Canadian Nuclear Fuel Waste Management Program has identified the need to quantify the properties of the intact rock surrounding the disposal vault that would control the transport of radionuclides by diffusion. The Postclosure Assessment also identified the need for appropriate values of the free water diffusion coefficient (D{sub o}) for {sup 129}1 and {sup 14}C. The measurement of rock resistivity allows the calculation of the Formation Factor for a rock This review describes the Formation Factor, diffusivity, permeability, and porosity, and how these properties might be measured or inferred for insitu rock under the conditions that apply to the intact rock surrounding a potential disposal vault. The importance of measuring the intrinsic diffusion coefficient (D{sup i}) of diffusing species under solution salinities simulating those of groundwaters is emphasised, and a method of measurement is described that is independent of the diffusing medium, and which would be appropriate for measurements made in chemically complex media such as groundwaters. (author). 95 refs., 4 tabs., 39 figs.

Measurement of diffusive properties of intact rock

International Nuclear Information System (INIS)

Harvey, K.B.

1996-12-01

In the Postclosure Assessment of a Reference System for the Disposal of Canada's Nuclear Fuel Waste (Goodwin et al. 1994) the disposal vault is assumed to be surrounded by a zone of intact rock, referred to as the 'exclusion zone.' A sensitivity analysis of the relative effectiveness of the several engineered and natural barriers that contribute to the safety of the reference disposal system has shown that this zone of intact rock is the most effective of these barriers to the movement of radionuclides through the reference system. Peer review of the geosphere model used in the case study for the EIS (Environmental Impact Statement) of the Canadian Nuclear Fuel Waste Management Program has identified the need to quantify the properties of the intact rock surrounding the disposal vault that would control the transport of radionuclides by diffusion. The Postclosure Assessment also identified the need for appropriate values of the free water diffusion coefficient (D o ) for 129 1 and 14 C. The measurement of rock resistivity allows the calculation of the Formation Factor for a rock This review describes the Formation Factor, diffusivity, permeability, and porosity, and how these properties might be measured or inferred for insitu rock under the conditions that apply to the intact rock surrounding a potential disposal vault. The importance of measuring the intrinsic diffusion coefficient (D i ) of diffusing species under solution salinities simulating those of groundwaters is emphasised, and a method of measurement is described that is independent of the diffusing medium, and which would be appropriate for measurements made in chemically complex media such as groundwaters. (author). 95 refs., 4 tabs., 39 figs

Mechanical dispersion in fractured crystalline rock systems

International Nuclear Information System (INIS)

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

1986-12-01

This report compiles and evaluates the hydrogeologic parameters describing the flow of groundwater and transport of solutes in fractured crystalline rocks. This report describes the processes of mechanical dispersion in fractured crystalline rocks, and compiles and evaluates the dispersion parameters determined from both laboratory and field tracer experiments. The compiled data show that extrapolation of the reliable test results performed over intermediate scales (10's of m and 10's to 100's of hours) to larger spatial and temporal scales required for performance assessment of a nuclear waste repository in crystalline rock is not justified. The reliable measures of longitudinal dispersivity of fractured crystalline rock are found to range between 0.4 and 7.8 m

Thermo-hydro-mechanical modelling of fractured rock masses application to radioactive wastes storage

International Nuclear Information System (INIS)

Vuillod, E.

1995-01-01

This work belongs to the Decovalex project (international cooperative project for the development of coupled models and their validation against experiments in nuclear waste isolation) of thermo-hydro-mechanical (THM) modeling of fractured rock massifs inside which high level radioactive waste disposal sites are simulated. The mathematical laws controlling the behaviour of the environment are resolved analytically in the case of a continuous environment (definition of an equivalent environment) and numerically if the environment is discontinuous (modeling of joints behaviour). The coupled THM models strongly influence the behaviour of a model. Modeling performed with the UDEC code shows the importance of HM couplings depending on whether the calculations are made in permanent or transient regime, and the influence of the loading path in the case of TM modeling. The geometry of fractures also influences the behaviour of the model. Studying the connexity of a fractures network allows to determine its degree of homogeneity. The comparison between two methods, continuous environment and discontinuous environment, has been carried out by determining the permeability tensor and the stress-deformation relations on fractured test-samples. It shows the differences in behaviour between an homogenized environment and a discrete environment. Finally two exercises of THM modeling of radioactive waste disposal sites illustrate the researches carried out. A far field model has permitted to compare the results obtained with calculation codes using different logics. The second model, a near field one, focusses more on the importance played by fracturing on the behaviour of the massif. The high density of the reference network has required some mathematical developments, in order to determine the representative equivalent volume (continuous approaches), and some mathematical analyses, to correctly simplify the environment (discontinuous approaches). These methods and analyses are

Characterisation of gas transport properties of the Opalinus clay, a potential host rock formation for radioactive waste disposal

International Nuclear Information System (INIS)

Marschall, P.; Horseman, S.; Gimmi, T.

2005-01-01

The Opalinus Clay in Northern Switzerland has been identified as a potential host rock formation for the disposal of radioactive waste. Comprehensive understanding of gas transport processes through this low-permeability formation forms a key issue in the assessment of repository performance. Field investigations and laboratory experiments suggest an intrinsic permeability of the Opalinus Clay in the order of 10 -20 to 10 -21 m 2 and a moderate anisotropy ratio ≤ 10. Porosity depends on clay content and burial depth; values of ∼ 0.12 are reported for the region of interest. Porosimetry indicates that about 10-30% of voids can be classed as macro-pores, corresponding to an equivalent pore radius > 25 nm. The determined entry pressures are in the range of 0.4-10 MPa and exhibit a marked dependence on intrinsic permeability. Both in situ gas tests and gas permeameter tests on drill-cores demonstrate that gas transport through the rock is accompanied by pore water displacement, suggesting that classical flow concepts of immiscible displacement in porous media can be applied when the gas entry pressure (i.e. capillary threshold pressure) is less than the minimum principal stress acting within the rock. Essentially, the pore space accessible to gas flow is restricted to the network of connected macro-pores, which implies a very low degree of desaturation of the rock during the gas imbibition process. At elevated gas pressures (i.e. when gas pressure approaches the level of total stress that acts on the rock body), evidence was seen for dilatancy controlled gas transport mechanisms. Further field experiments were aimed at creating extended tensile fractures with high fracture transmissivity (hydro- or gas-fractures). The test results lead to the conclusion that gas fracturing can be largely ruled out as a risk for post-closure repository performance. (authors)

Nuclear waste management by in-situ melting

International Nuclear Information System (INIS)

Angelo, J.A. Jr.

1976-01-01

A systematic assessment of the in-situ melting concept as an ultimate waste disposal option shows that the placement of solidifed, high-level radioactive wastes in an in-situ melting cavity with a crushed rock backfill not only eliminates the major deficiencies inherent in other in-situ melting schemes, but also satisfies reasonable criteria for ultimate disposal. In-situ melting reduces the waste isolation time requirements to several hundred years. Calculated spent fuel and processing waste afterheat values assess the role of actinide and cladding material nuclides in creating the total afterheat and provide quantitative variation with time for these values for contamporary and advanced-design fission reactors. The dominant roles of 134 Cs in thermal spectrum reactor afterheats during the first decade of cooling of the actinide nuclides in all typical waste after-heats following a century or two of cooling are identified. The spatial and temporal behavior of a spherically symmetric waste repository experiencing in-situ melting in an equal density, homogeneous medium for silicate rock and salt is controlled primarily by the overall volumetric thermal source strength, the time-dependent characteristics of the high-level wastes, and the thermophysical properties of the surrounding rock environment. Calculations were verified by experimental data. The hazard index for typical high-level wastes is dominated by the fission product nuclides for the first three centuries of decay. It is then controlled by the actinides, especially americium, which dominates for 10,000 years. With in-situ melting, the hazard index for the re-solidifed rock/waste matrix deepunderground falls below the hazard index of naturally occurring uranium ore bodies within a few hundred years, whether or not the more hazardous actinide nuclides are selectively removed from the wastes prior to storage

Rock fracture dynamics research at AECL's Underground Research Laboratory: applications to geological disposal of radioactive waste

Energy Technology Data Exchange (ETDEWEB)

Young, R.P. [Univ. of Toronto, Toronto, ON (Canada); Haycox, J.R. [Applied Seismology Consultants Limited, Shrewsbury, Shropshire (United Kingdom); Martino, J. [Atomic Energy of Canada Limited, Pinawa, MB (Canada)

2011-07-01

Studies of rock fracture dynamics at AECL's Underground Research Laboratory (URL) have helped to provide a fundamental understanding of how crystalline rock responds to stresses induced from excavation, pressurization and temperature changes. The data acquired continue to provide insights into how a facility for the future geological disposal of radioactive waste could be engineered. Research into microseismic (MS), acoustic emission (AE), and ultrasonic velocity measurements has been performed on the full-scale sealed, pressurized, and heated horizontal elliptical tunnel at the Tunnel Sealing Experiment (TSX). The continuous monitoring of the experiment for 8 years provides a unique dataset for the understanding of the medium-term performance of an engineered disposal facility. This paper summarizes the results, interpretations and key findings of the experiment paying particular focus to the heating and cooling/depressurization of the chamber. Initial drilling of the tunnel and bulkheads causes microfracturing around the tunnel, mapped by MS and AEs, and is used as a benchmark for fracturing representing the excavated damaged zone (EDZ). There is no further extension to the volume during pressurization or heating of the tunnel suggesting an increase in crack density and coalescence of cracks rather than extension into unfractured rock. The dominant structure within the seismic cloud has been investigated using a statistical approach applying the three-point method. MS events in the roof exhibit a dominant pattern of sub-horizontal and shallow-dipping well defined planar features, but during cooling and depressurization a 45 degree dip normal to the tunnel axis is observed, which may be caused by movement in the rock-concrete interface due to differential cooling of the bulkhead and host rock. Cooling and depressurization of the TSX have not led to a significant increase in the number of MS or AE events. Ultrasonic results suggest the rock gets even stiffer

Effects of tuff waste package components on release from 76-68 simulated waste glass: Final report

International Nuclear Information System (INIS)

McVay, G.L.; Robinson, G.R.

1984-04-01

An experimental matrix has been conducted that will allow evaluation of the effects of waste package constituents on the waste form release behavior in a tuff repository environment. Tuff rock and groundwater were used along with 304L, 316, and 1020M ferrous metals to evaluate release from uranium-doped MCC 76-68 simulated waste glass. One of the major findings was that in the absence of 1020M mild steel, tuff rock powder dominates the system. However, when 1020M mild steel is present, it appears to dominate the system. The rock-dominated system results in suppressed glass-water reaction and leaching while the 1020M-dominated system results in enhanced leaching - but the metal effectively scavenges uranium from solution. The 300-series stainless steels play no significant role in affecting glass leaching characteristics. 6 refs., 28 figs., 5 tabs

Reforestation and landscape reconstruction in gypsum mine area from the semiarid region of NE Brazil

Science.gov (United States)

Bittar, S. M. B.; Straaten, P. V.; de Araujo Vieura Santos, M. de Fatima; Agra Bezerra da Silva, Y. J.; da Silva, M.; Saraiva de Melo Pinheiro, T.; Gusmao Didier de Moraes, F.; de Aguiar Accioly, A. M.; Alves de Santana, S. R.; dos Santos, H. A.; de Carvalho, D. M.; de Lima Ferreira, G.; de Carvalho Santos, C.

2012-04-01

In the Araripe region, Northeast Brazil, exist the world's second largest reserve of gypsum, estimated at over than one billion tons, which accounts for 95% of the Brazilian production and constitutes an important segment of the regional economy. The gypsum deposit occurs in the Lower Cretaceous Santana Formation of the Araripe basin, which is constituted by siltstones, marls, limestones, shales and gypsum layers. The ore extraction is from an open pit, on simple benches with a height of about 15 meters. Activities in mining operations involve stripping, drilling, loading explosives, blast, fragmentation and block loading / transport. Currently, gypsum mining and processing results in major changes in the landscape (pits and wastes heaps sedimentary rocks and soil mixture), deforestation of the "caatinga" ecosystem for use as firewood in small calcinations, dust pollution and changes in hydrology. To promote environmental remediation of this area, a multidisciplinary research has being done with the aim to support reforestation at the wastes heaps. The study involved the following activities: collection and physical, chemical and mineralogical characterization of mine waste materials; a floristic survey around the mines (botanical identification and measuring physical parameters in 16 plots, in order to identify which species are best suited to the conditions of the substrate at the mine site); an experiment (randomized block design) developed in a greenhouse, where seedlings of various native tree species were grown in a "constructed soil" made up of gypsum waste combined with chicken, goat and cattle manure, aimed to select tree species and soil treatment to be used in a waste heap; and an assessment of water quality for irrigation of the reforestation areas. The waste materials consist of large clayey aggregates, which may present physical/chemical properties unfavorable for plant development. The mineralogy of the sand fraction (> 85% quartz, gypsum and

Preliminary rock mechanics laboratory: Investigation plan

International Nuclear Information System (INIS)

Oschman, K.P.; Hummeldorf, R.G.; Hume, H.R.; Karakouzian, M.; Vakili, J.E.

1987-01-01

This document presents the rationale for rock mechanics laboratory testing (including the supporting analysis and numerical modeling) planned for the site characterization of a nuclear waste repository in salt. This plan first identifies what information is required for regulatory and design purposes, and then presents the rationale for the testing that satisfies the required information needs. A preliminary estimate of the minimum sampling requirements for rock laboratory testing during site characterization is also presented. Periodic revision of this document is planned

Penetration of liquid fingers into superheated fractured rock

Science.gov (United States)

Birkholzer, Jens

2003-04-01

Water infiltrating down a fracture in unsaturated rock experiences complex fluid flow and heat transfer phenomena when entering above-boiling rock temperature regions. Such conditions are expected, for example, after emplacement of heat-generating nuclear waste in underground repositories. A new efficient semianalytical method is proposed in this paper that simulates the flow processes of infiltration events subject to vigorous boiling from the adjacent hot rock. It is assumed that liquid flow forms in localized preferential flow paths and that infiltration events are typically short in duration but large in magnitude relative to the average net infiltration. The new solution scheme is applied to several test cases studying sensitivity to a variety of input parameters. Sample simulations are performed for conditions representative of the potential nuclear waste repository at Yucca Mountain, Nevada. A characteristic parameter is introduced that provides a quick estimate of the relative significance of boiling at a given location of interest.

Penetration of liquid fingers into superheated fractured rock

International Nuclear Information System (INIS)

Birkholzer, Jens

2002-01-01

Water infiltrating down a fracture in unsaturated rock experiences complex fluid-flow and heat-transfer phenomena when entering above-boiling rock temperature regions. Such conditions are expected, for example, after emplacement of heat-generating nuclear waste in underground repositories. A new, efficient semi-analytical method is proposed in this paper that simulates the flow processes of infiltration events subject to vigorous boiling from the adjacent hot rock. It is assumed that liquid flow forms in localized preferential flow paths, and that infiltration events are typically short in duration but large in magnitude relative to the average net infiltration. The new solution scheme is applied to several test cases studying sensitivity to a variety of input parameters. Sample simulations are performed for conditions representative of the potential nuclear waste repository at Yucca Mountain, Nevada. A characteristic parameter is introduced that provides a quick estimate of the relative significance of boiling at a given location of interest

The Ypresian clays as alternative host rock for radioactive waste disposal in Belgium. A transferability study

International Nuclear Information System (INIS)