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Unconformity-related uranium (URU) deposits in the Athabasca Basin occur in local areas near the intersections of the basal unconformity of the basin and regional-scale, basement-rooted faults. This study examines the ore-controlling factors through analysis of fluid inclusions from syn-mineralization drusy quartz in mineralized and distal (> 500 m away from mineralized zones) barren areas of two major URU-hosting structures: the P2 fault in the eastern, and the Patterson Lake corridor (PLC) in the southwestern, parts of the basin. Microthermometric data indicate that fluids in mineralized zones have salinities ranging from 24.8 to 31.7 wt.% NaCl + CaCl2 and homogenization temperatures (Th) from 64 to 227 °C, which are comparable with those from distal barren areas with salinities ranging from 25.2 to 32.5 wt.% NaCl + CaCl2 and Th from 91 to 213 °C. Laser ablation-inductively coupled plasma-mass spectrometry analyses of individual fluid inclusions indicate that the fluids have elevated concentrations of U in both mineralized zones (0.50 to 109 mg/kg) and distal barren areas (0.32 to 73.8 mg/kg). Bulk fluid inclusion analyses also indicate elevated U concentrations for mineralized zones (0.39 to 1560 mg/kg) and distal barren areas (0.12 to 1.5 mg/kg), and U was detected in fluid inclusions from both mineralized and distal areas with synchrotron X-ray fluorescence mapping. The development of uraniferous fluids with similar geochemistry in distant areas with different basement lithologies supports the hypothesis that U for mineralization was mainly derived from the basin. The presence of uraniferous fluids with similar thermal and compositional characteristics in both mineralized zones and distal barren areas along the same structures with similar lithologies suggests that mixing of U-rich fluids with reductants-carrying fluids played a critical role in ore precipitation; lack or low flux of either or both fluids resulted in lack or poor development of mineralization. [ABSTRACT FROM AUTHOR]

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Background: The authors assessed the association between radon decay products (RDP) exposure and histologic types of incident lung cancer in a cohort of 16,752 (91.6% male) Eldorado uranium workers who were first employed from 1932 to 1980 and were followed through 1969-1999.Methods: Substantially revised identifying information and RDP exposures were obtained on workers from the Port Radium and Beaverlodge uranium mines and from the Port Hope radium and uranium refinery and processing facility in Canada. Poisson regression was conducted using the National Research Council's Biological Effects of Ionizing Radiation (BEIR) VI-type models to estimate the risks of lung cancer by histologic type from RDP exposures and γ-ray doses.Results: Lung cancer incidence was significantly higher in workers compared with the general Canadian male population. Radiation risks of lung cancer for all histologic types (n = 594; 34% squamous cell, 16% small cell, 17% adenocarcinoma) increased with increasing RDP exposure, with no indication of curvature in the dose response (excess relative risk per 100 working level months = 0.61; 95% confidence interval, 0.39-0.91). Radiation risks did not differ by histologic type (p = .144). The best-fitting BEIR VI-type model included adjustments for the significant modifying effects of time since exposure, exposure rate, and attained age. The addition of γ-ray doses to the model with RDP exposures improved the model fit, but the risk estimates remained unchanged.Conclusions: The first analysis of radiation risks of lung cancer histologic types in the Eldorado cohort supported the use of BEIR VI-type models to predict the future risk of histologic types of lung cancer from past and current RDP exposures.Lay Summary: Lung cancer survival depends strongly on the cell type of lung cancer. The best survival rates are for patients who have the adenocarcinoma type. This study included 16,752 Eldorado uranium workers who were exposed to radon and γ-ray radiation during 1932-1980, were alive in 1969, and were followed for the development of new lung cancer during 1969-1999. One third of all lung cancers were of the squamous cell type, whereas the adenocarcinoma and small cell types accounted for less than 20% each. Radiation risks of lung cancer among men increased significantly with increasing radon exposure for all cell types, with the highest risks estimated for small cell and squamous cell lung cancers. [ABSTRACT FROM AUTHOR]

Recent fluid inclusion analysis indicates that uranium‐bearing brines were present in both the sandstone and the basement at the time of ore genesis in the Athabasca Basin, Canada. However, the question of how the location of uranium‐rich brines controls the formation of unconformity‐related uranium deposits remains unresolved. In this study, four reactive flow modeling scenarios are designed to address this outstanding issue. Our numerical results confirm that the basement‐hosting uranium‐rich brines are capable of forming high‐grade concentrated uranium deposits in the footwall region of the fault zone below the unconformity interface. In contrast, the sandstone‐hosting uranium‐rich brines lead to the formation of low‐grade sheet‐like uranium mineral precipitates above the sandstone layer rather than in the basement. Therefore, this study reveals that unconformity‐related uranium deposits tend to be formed when the basement unit serves as the main uranium source. Taking the sandstone layer as the main uranium source, no unconformity‐related uranium deposits can be formed since the resultant uranium precipitation has no spatial relation with the unconformity interface. Key Points: First numerical investigation into the role of the location of uranium‐rich brines in controlling unconformity‐related uranium depositionBasement‐hosting uranium‐rich brines favor the formation of unconformity‐related uranium depositsSandstone‐hosting uranium‐rich brines do not support the formation of unconformity‐related uranium deposits [ABSTRACT FROM AUTHOR]

Unconformity‐related uranium (URU) deposits in the Athabasca Basin, Canada, include the highest grade, large tonnage deposits in the world. Recent studies of the Patterson Lake corridor uranium deposits suggest a deep heat source enhances hydrothermal fluid flow and incursion of basinal brines along brittlely reactivated ductile shear zones. However, the spatial extent of the ore systems and lower crustal features capable of driving the hydrothermal cells remained largely unresolved. Three‐dimensional electrical conductivity models derived from inversion of magnetotelluric data and coincident gravity modeling identified a voluminous conductivity anomaly and corresponding gravity low related to a belt of high‐heat producing intrusions that dips below the deposit. Shallow conductive bodies are identified below the deposits and similarly prospective corridors. The volume and location of the intrusive bodies may have provided a source of radiogenic heat that helped drive remobilization of fluids along reactivated structures, redefining the spatial extent of URU systems. Plain Language Summary: The western Athabasca Basin, straddling the border of Saskatchewan and Alberta in Canada, is home to some of the highest‐grade, large tonnage uranium deposits in the world. Recent studies have suggested a spatial connection between uranium ore systems that are found near the earth's surface and geological processes occurring deep within the crust. However, the processes connecting the lower crust to these shallow deposits is poorly understood. This study used 3D models created from magnetotelluric data, a passive a geophysical technique that measures the earth's natural electric and magnetic fields, to image the earth from surface to a depth of 40 km. We identified a voluminous igneous intrusion that extends from the surface to great depths in the earth's crust. We propose that this intrusion may have contributed to the uranium endowment of the basin, and that radiogenic heat from the large igneous body helped circulate uranium‐bearing fluids through the shallow crust along reactivated geologic structures. The modeling, when combined with other geoscientific datasets, showcases the role of high‐heat producing granitic intrusions in driving the hydrothermal fluid cells that formed the deposits. Key Points: Integrated resistivity—gravity modeling over the Arrow uranium deposit in CanadaMagnetotelluric inversion images deep‐seated thermal source and fluid pathways that formed some of the highest‐grade uranium depositsHolistic ore system model illustrates relationship between crustal ore system and lower crustal resistivity anomalies [ABSTRACT FROM AUTHOR]

In this study, a conceptual model is developed based on common features of typical unconformity-related uranium deposits in the Athabasca Basin, Canada. Three reactive flow modeling scenarios are designed to address the effect of fault extension on the formation of uranium deposits. Our results indicate that the location of the fault zone relevant to the unconformity is crucial to the fluid circulation in both the sandstone layer and the basement unit, the temperature distribution, the transport of aqueous components, and the uranium deposition. In particular, this research reveals that the circulating pattern of the basement brine is critical for the ore genesis. The reducing basal brine is capable of carrying aqueous uranium from depth to react with the shallow oxidizing fluid, being percolated to the basement from the overlain sandstone layer, for uranium precipitation. Scenarios 1 and 2, in which the fault zone is mainly in the basement, are in favor of focusing ore-forming hydrothermal fluids into the footwall area in the basement, leading to the formation of uranium deposits therein. Scenario 3, in which the fault zone is mainly in the sandstone layer with a limited extension below the unconformity, is unfavorable for the focusing of fluids, and hence no significant deposits can be formed, except for some minor uranium mineralization occurring in the footwall and other areas in the basement that are spatially associated with the upwelling flow zones in the sandstone layer. [ABSTRACT FROM AUTHOR]

This thematic issue is in memory of Thomas Kurtis Kyser who died tragically in 2017. Kurt's contribution to our understanding of the geochemistry of uranium deposits and the application of stable and radiogenic isotope studies to uranium ore systems is incalculable. His research on uranium deposits included the world-class unconformity-related uranium deposits from Canada, Australia, and Russia, and several other major types of uranium deposits worldwide such as Na-metasomatic deposit of Kurupung (Guyana) and Valhalla (Australia), volcanic-hosted deposits of Peru (Macusani), and vein-type uranium deposits from Beaverlodge district (Canada). He was the first to develop methods to use secondary dispersion of pathfinder elements to vector towards deeply buried uranium ore systems. These new geochemical and isotopic approaches are still successfully applied today. Kurt has been a pioneer in applying stable isotopic systems to characterize the paleofluid events associated with ore systems and to distinguish between barren and mineralized fluid pathways. Kurt was a prolific author with over 400 publications and over a hundred articles on uranium deposits. Kurt wrote three short courses for the Mineralogical Association of Canada dedicated to uranium deposits: Fluids and Basin Evolution (2000), Recent and not-so-Recent Developments in Uranium Deposits and Implications for Exploration (2008, in partnership with SGA), and Geology and Geochemistry of Uranium and Thorium Deposits (2015). However, his true legacy is the large number of undergraduate and graduate students, post-docs, and researchers that he taught, supervised, and mentored; most of whom are now working in industry, academia, and government institutions across the globe. He will be missed. [ABSTRACT FROM AUTHOR]

The Cigar Lake uranium deposit in the Athabasca Basin is the world's second largest high-grade unconformity-related uranium deposit. Its distinct geological architecture includes heterogeneous basement lithologies, a local basement high and sub-vertical faults. The sub-vertical faults are classified further into two sub-types: faults that are restricted to the basement, termed 'basement faults', and faults that are distinctly related to post-Athabasca fault reactivation, in that they extend upward into the sandstone, termed 'extended basement faults'. This study aims to evaluate the effects of the aforementioned geological factors on the fluid flow patterns under two different driving forces, buoyancy due to variation of fluid density or 'thermal convection' and deformation or a combination of them, and to determine the most probable fluid flow scenarios for the formation of the deposit. The numerical results show that fluid flow is strongly affected by the two types of faults. While the basement faults represent fluid paths with complex fluid flow patterns, depending on the driving forces, providing favourable physical conditions for different chemical processes, such as fluid-fluid and fluid-rock interactions, the extended basement faults enhance the permeability of an E-W corridor within the sandstone and significantly strengthen the overall upwelling flow above the basement faults, promoting sandstone-hosted mineralization. The numerical results also suggest that the main deposit likely formed via fluid convection during tectonically quiet periods, although faulting played a critical role in increasing permeability, in turn, enhancing thermal convection. [ABSTRACT FROM AUTHOR]

A number of large and high-grade unconformity-related uranium deposits formed in intracratonic Proterozoic basins, including the Athabasca Basin in Canada and the McArthur Basin in Australia. These deposits occur close to the unconformities between the Paleo- to Mesoproterozoic basinal sequences and their Archean to Paleoproterozoic metasedimentary basement, and are spatially associated with reactivated basement faults showing reverse offsets due to contractional deformation. Previous studies have suggested that fluid flow responsible for uranium mineralization in such basins may be related to thermal convection and tectonic deformation; however, the relative roles of these two driving forces, as well as their interrelationships, have not been explored in detail. In this study, two-dimensional numerical modeling of fluid flow in relation to coupled tectonic compression and heat transport was carried out to evaluate the relationships between deformation-driven flow and fluid convection, and their relative importance for uranium mineralization. The results indicate that tectonic compression at a relatively high strain rate (6.66 × 10−11 s−1) may instantaneously destroy pre-existing thermal convection developed in the sedimentary rocks in the basin, due to the rapid development of overpressure in the system. Convection may then reappear over time as deformation progresses and the overpressure wanes. By contrast, tectonic compression at a relatively low strain rate (6.66 × 10−13 s−1) does not affect pre-existing thermal convection, and deformation-driven fluid flow in the basement coexists with thermal convection in the basin. It is proposed that during an overall tectonically active period associated with a far-field tectonic event, compressional reactivation of basement faults creates permeability and causes fluid to flow toward dilatant zones accompanying individual seismic events, whereas during seismically quiet times, fluid flow driven by thermal convection dominates. The formation of the unconformity-related uranium deposits likely involves alternating relatively short-lived, deformation-driven fluid flow and relatively prolonged fluid convection events. [ABSTRACT FROM AUTHOR]

The paper is concerned with thermal disturbances in continuous permafrost due to open pit mining and tailings impoundment in the cold regions of Northern Canada. Numerical simulations were conducted to investigate issues of thermal regime changes and permafrost degradation in both the short term and the long term in connection with the proposed Kiggavik project in Nunavut, Canada. The results of numerical simulations indicate that no open talik would form below the East Zone and Center Zone pits during the estimated mining and milling operation period of 14 years, although a thin thawed zone would develop surrounding the open pits. For the Main Zone pit where the excavation would break through permafrost, the open talik remains following an extended operation period of 25 years with a 5 to 30 m thawed zone along the pit side walls. In the long term, with a plausible climate change scenario of 5 °C increase in the mean annual ground surface temperature during the next 100 years, the permafrost surrounding the in-pit tailings management facilities (TMFs) would reduce greatly in about 500 years. However, an approximately 40 m thick permafrost layer would remain on the top of the TMFs, which is impervious and would prevent any tailings pore water from migrating upward to reach the ground surface. [ABSTRACT FROM AUTHOR]

The Millennium deposit, a c. 650-m deep monomineralic uranium deposit, is located in the southeastern Athabasca Basin, Saskatchewan, a region containing numerous high-grade unconformity-type U deposits. 3D modelling of the whole-rock lithogeochemistry of sandstones above the deposit reveals a distinct footprint with select major and trace elements showing increased concentrations towards mineralization. Molar Mg/K ratios increase from background levels 10 km north of the deposit, along the B1 conductive trend, whereas Mo, Co, Rb, and Ga exhibit elevated concentrations immediately above the deposit, extending vertically from the unconformity to surface. Lead, Ag, Bi, Sb, REE, and Y exhibit elevated concentrations up to 650 m above the main mineralized body. Increasing Mg/K values indicate the transition from diagenetic to hydrothermal alteration with shifts from illitic (K-dominant) to chloritic and dravitic (Mg-dominant) alteration, with the latter increasing more proximal to mineralization. Trace element enrichment patterns highlight that fractures and faults were conduits for fluid flow from the basement into the basin, both during ore formation and through tectonically driven post-depositional remobilization. Key indicators such as molar element ratios (Mg-K-Al) and trace elements related to redox reactions provide scalable vectors at the Millennium deposit that are likely applicable to similar unconformity-type U deposits elsewhere. [ABSTRACT FROM AUTHOR]

There is hardly any study on environmental impacts of uranium exploration and mining development prior to actual mining activities. Rather, the majority of the literature addresses the environmental impacts of either ongoing or decommissioned mines. The objective of the study was to measure the possible radioactive contamination (total uranium and lead) in the local ecosystem surrounding an abandoned uranium development site on indigenous land in Labrador (Canada). Water (brook and ponds), soil/sediments (brook and ponds), plants (growing along the brook and pond shores), and local fish (trout) and clams from bays were collected from mine development site, downstream, and control sites. Uranium and lead mobilization in the local environment appears to be slightly enhanced near the proposed mining site, but rapidly drops downstream. Developing a low-cost, community-based environmental health monitoring tool is an ideal strategy for generating baseline information and further follow-up. [ABSTRACT FROM AUTHOR]

The article discusses the sources of uranium, and observes its principal occurrence in several countries around the world. The carrying out of uranium research has been kept in the highest level of concealment from media. However, its confidentiality has subsided due to the open statements made by government officials in several countries they possess radioactive resources. These countries include Canada, Australia, France and Sweden. In the U.S. alone, its geologic effort to explore possible resources of uranium is extensive ranging from the Belgian Congo and Canada, and some quantities derived from Colorado. Details about the exploration activities carried out by U.S. Geological Survey are outlined, as well as the three classification of uranium deposits.

Nuclear colonialism, or the exploitation of Indigenous lands and peoples to sustain the nuclear fuel cycle from uranium mining and refining to nuclear energy and weapons production and the dumping of the resulting nuclear waste, occurs in many parts of the world and has generated considerable protest. This article focuses on a contemporary and ongoing case of nuclear colonialism in Canada: attempts to site two national deep geological repositories (DGRs) for nuclear waste on traditional First Nations land in Southwestern Ontario near the world’s largest operational nuclear power plant. Through histories of the rise of nuclear power and nuclear waste policy-making and their relationship to settler colonialism in Canada, as well as actions taken by the Saugeen Ojibway Nation (SON) and white settler anti-nuclear waste movements, the article explores how gender is at work in nuclear colonialism and anti-nuclear waste struggles. Gender is explored here in terms of the patriarchal nuclear imperative, the appropriation of Aboriginal land through undermining Aboriginal women’s status and the problematic relationship between First Nations and white settler women-led movements in resistance to nuclear waste burial from a feminist decolonial perspective [ABSTRACT FROM AUTHOR]

The rise and abandonment of Uranium City constitutes an environmental history yet to be fully evaluated by humanities scholars. 1982 marks the withdrawal of the Eldorado Corporation from the town and the shuttering of its uranium mines. The population declined to approximately 50 from its pre-1982 population of about 4000. This article is inspired by findings from the authors' initial field visit. As Uranium City is accessible only by air or by winter roads across Lake Athabasca, the goal of the visit in May 2017 was to gather information and questions through photographic assessment and through communication and interviews with residents. This paper in part argues that the cyclonic development metaphor used to describe single-commodity communities naturalizes environmental damage and obscures a more complicated history involving human agency. Apart from the former mines that garner remedial funding and action, the town site of Uranium City is also of environmental concern. Its derelict suburbs and landfill, we also argue, could benefit from assessment, funding, and remediation. Canada's 2015 Truth and Reconciliation Commission Report provides a way forward in healing this region, in part by listening to the voices of those most affected by environmental impacts caused not by a metaphorical cyclone but by other humans' decisions. As descendants of European immigrants to Turtle Island (the Indigenous term referring to North America), the authors are also subjects of the very terms-cyclonic development, abandonment, remediation-used to describe the history of the land itself: in this case, a mining town in the far northern boreal forests and Precambrian Shield. [ABSTRACT FROM AUTHOR]

Previous studies on unconformity-related uranium deposits in the Athabasca Basin (Canada) suggest that egress flow and ingress flow can develop along single fault systems at different stages of compressional deformation. This research aims to examine whether or not both ingress and egress flow can develop at the same time within an area under a common compressional stress field, as suggested by the reverse displacement of the unconformity surface by the basement faults. The study considers the Phoenix and Gryphon uranium deposits in the Wheeler River area in the southeastern part of the Athabasca Basin. Two-dimensional numerical modeling of fluid flow, coupled with compressional deformation and thermal effects, was carried out to examine the fluid flow pattern. The results show that local variations in the basement geology under a common compressional stress field can result in both egress and ingress flow at the same time. The fault zone at Phoenix underwent a relatively low degree of deformation, as reflected by minor reverse displacement of the unconformity, and egress flow developed, whereas the fault zone at Gryphon experienced a relatively high degree of deformation, as demonstrated by significant reverse displacement of the unconformity, and ingress flow was dominant. The correlation between strain development and location of uranium mineralization, as exemplified by Gryphon and Phoenix uranium deposits, suggests that the localization of dilation predicted by numerical modeling may represent favourable sites for uranium mineralization in the Athabasca Basin. [ABSTRACT FROM AUTHOR]

Purpose: Long-term health risks of occupational exposures to uranium processing were examined to better understand potential differences with uranium underground miners and nuclear reactor workers. Methods: A cohort study of mortality of workers from Port Hope, Canada (1950-1999) and Wismut, Germany (1946-2008) employed in uranium milling, refining, and processing was conducted. Poisson regression was used to evaluate the association between cumulative exposures to radon decay products (RDP) and gamma-rays and causes of death potentially related to uranium processing. Results: The pooled cohort included 7431 workers (270,201 person-years of follow-up). Mean RDP exposures were lower than in miners while gamma-ray doses were higher than in reactor workers. Both exposures were highly correlated (weighted rho = 0.81). Radiation risks of lung cancer and cardiovascular diseases (CVD) in males were increased but not statistically significant and compatible with risks estimated for miners and reactor workers, respectively. Higher RDP-associated CVD risks were observed for exposures 5-14 years prior to diagnosis compared to later exposures and among those employed <5 years. Radiation risks of solid cancers excluding lung cancer were increased, but not statistically significant, both for males and females, while all other causes of death were not associated with exposures. Conclusions: In the largest study of uranium processing workers to systematically examine radiation risks of multiple outcomes from RDP exposures and gamma-rays, estimated radiation risks were compatible with risks reported for uranium miners and nuclear reactor workers. Continued follow-up and pooling with other cohorts of uranium processing workers are necessary for future comparisons with other workers of the nuclear fuel cycle. [ABSTRACT FROM AUTHOR]

Resistivity methods are commonly used in mineral exploration to map lithology, structure, sulphides and alteration. In the Athabasca Basin, resistivity methods are used to detect alteration associated with uranium. At the Midwest deposit, there is an alteration zone in the Athabasca sandstones that is above a uraniferous conductive graphitic fault in the basement and below a conductive lake at surface. Previous geophysical work in this area has yielded resistivity sections that we feel are ambiguous in the area where the alteration is expected. Resolve® and TEMPEST sections yield an indistinct alteration zone, while two-dimensional (2D) inversions of the ground resistivity data show an equivocal smeared conductive feature in the expected location between the conductive graphite and the conductive lake. Forward modelling alone cannot identify features in the pseudosections that are clearly associated with alteration, as the section is dominated by the feature associated with the near-surface conductive lake; inverse modelling alone produces sections that are smeared and equivocal. We advocate an approach that uses a combination of forward and inverse modelling. We generate a forward model from a synthetic geoelectric section; this forward data is then inverse modelled and compared with the inverse model generated from the field data using the same inversion parameters. The synthetic geoelectric section is then adjusted until the synthetic inverse model closely matches the field inverse model. We found that this modelling process required a conductive alteration zone in the sandstone above the graphite, as removing the alteration zone from the sandstone created an inverse section very dissimilar to the inverse section derived from the field data. We therefore conclude that the resistivity method is able to identify conductive alteration at Midwest even though it is below a conductive lake and above a conductive graphitic fault. We also concluded that resistivity inversions suggest a conductive paleoweathering surface on the top of the basement rocks at the basin/basement unconformity. [ABSTRACT FROM AUTHOR]

Graphitic shear zones are spatially associated with unconformity-related uranium deposits that are located around the unconformity between the strata of the Paleo- to Mesoproterozoic Athabasca Basin (Saskatchewan, Canada) and its underlying Archean to Paleoproterozoic basement. The present study focuses on basement-hosted ductile-brittle graphitic shear zones near the Cigar Lake U deposit, one of the largest unconformity-related U deposits. The goal of the study is to decipher the pre-Athabasca Basin fluid migration history recorded within such structures and its potential role on the formation of such exceptional deposit. Dominantly C-O-H(-N) metamorphic fluids have been trapped in Fluid Inclusion Planes (FIPs) in magmatic quartz within ductile-brittle graphitic shear zones active during retrograde metamorphism associated with the formation of the Wollaston-Mudjatik Transition Zone (WMTZ) between ca. 1805 and 1720 Ma. Such fluids show a compositional evolution along the retrograde path, from a dense and pure CO 2 fluid during the earliest stages, through a lower density CO 2 ± CH 4 -N 2 (± H 2 O) fluid and, finally, to a very low density CH 4 -N 2 fluid. Statistical study of the orientation, distribution, proportion, and chemical characterization of the FIPs shows that: i) CO 2 (δ 13 C CO2 around − 9‰ PDB) from decarbonation reactions and/or partial water-metamorphic graphite equilibrium initially migrated regionally and pervasively under lithostatic conditions at about 500 to 800 °C and 150 to 300 MPa. Such P-T conditions attest to a high geothermal gradient of around 60 to 90 °C/km, probably related to rapid exhumation of the basement or a large-scale heat source. ii) Later brittle reactivation of the shear zone at around 450 °C and 25–50 MPa favored circulation of CO 2 -CH 4 -N 2 (± H 2 O) fluids in equilibrium with metamorphic graphite (δ 13 C CO2 around − 14‰) under hydrostatic conditions and only within the shear zones. Cooling of these fluids and the water uptake linked to fluid-basement rock reactions led to the precipitation at around 450 °C of poorly-crystallized hydrothermal graphite. This graphite presents isotopic (δ 13 C − 30 to − 26‰ PDB) and morphological differences from the high-T metamorphic graphite (> 600 °C, − 29 to − 20‰ δ 13 C) derived from metamorphism of C-rich sedimentary material. The brittle structural reactivation and the related fluid migration and graphite precipitation were specifically focused within the shear zones and related damage zones. The brittle reactivation produced major changes in the petro-physical, mineralogical, and chemical characteristics of the structures and their damage zones. It especially increased the fracture paleoporosity and rock weakness toward the fault cores. These major late metamorphic modifications of the graphitic shear zones were likely key parameters favoring the enhanced reactivity of these basement zones under tectonic stress following deposition of the Athabasca Basin, and so controlled basinal brine movement at the basin/basement interface related to the formation of the unconformity-related uranium deposits. This relationship consequently readily explains the specific spatial relationships between unconformity-related U deposits and the ductile-brittle graphitic shear zones. [ABSTRACT FROM AUTHOR]

Although intersection zones of two or more fault arrays have been identified as favorable loci of unconformity-related basin-basement mineral deposits in previous studies, their roles in controlling fluid flow patterns related to formation of oriented-, and structurally-controlled mineral deposits remain unclear. In this study, 3-D hydromechanical models were conducted to better understand the response of a natural fault intersected by a hydraulic fault under different stress regimes. A comprehensive parametric study was carried out to assess the roles of fluid pressure, burial depth, basin permeability, intersection angle, and horizontal differential stress on the hydromechanical response of a system containing two intersecting faults. Depending on basin sediment permeability, fault intersection angle, and horizontal differential stress, the fluid flow either stops, crosses, or diverts toward natural fault. Among the tested parameters, the intersection angle, and horizontal differential stress have the most noticeable effect on the fluid flow in the system. The critical intersection angle at which the fluid flow diverts toward the natural fault varies between ≈27° in normal faulting regimes, to ≈55°, in both strike-slip and reverse faulting regimes. Conversely, burial depth and fluid pressure have no significant effect on fluid flow diversion in the intersection zone. The results are in agreement with field observations related to the unconformity-related uranium deposits found in northern Canada. [ABSTRACT FROM AUTHOR]

The Thelon Basin located in Nunavut, Canada, shares many similarities with the U-producing Athabasca Basin in Saskatchewan. The Kiggavik project area, located near the northeastern edge of the Thelon Basin, contains U deposits and showings along the ∼30 km long NE-SW Kiggavik - Andrew Lake structural trend. The Andrew Lake deposit is near the southern end of this trend. Pre-mineralization is characterized by quartz ± carbonate veins that occupy fault systems later reactivated as conduits for U-mineralizing fluids. A four-phase genetic model is proposed for the Andrew Lake deposit. Phase 1 comprises vein-style uraninite (U1; 1031 ± 23 Ma) that is associated with illite and hematite, and contains variable PbO contents (0.2-9.5 wt.%). Phase 2 is characterized by altered uraninite (U2; ∼530 Ma) that is associated with coffinite. Altered uraninite (U3; <1 Ma) characterizes phase 3 and occurs as centimetre-scale 'roll-fronts'. In phase 4, all three uraninite stages, and coffinite, are altered to boltwoodite. Although the oldest uraninite U-Pb age is ∼1030 Ma, illite associated with the U mineralization gives 40Ar/39Ar ages of 941 ± 31 and 1330 ± 36 Ma. The younger age is similar to the age for U1, suggesting that there was a fluid event that either precipitated U1 or reset the U-Pb isotopic system at ∼1000 Ma. While the older age for illite (1330 Ma) does not correlate with Andrew Lake U-Pb uraninite ages, it does correlate with ages previously reported for uraninite and clay alteration minerals in the Kiggavik area. [ABSTRACT FROM AUTHOR]

ABSTRACT Current models for unconformity-associated uranium deposits predict fluid flow and ore deposition along reactivated faults in >1.76 Ga basement beneath Mesoproterozoic siliciclastic basins. In frontier regions such as the Thelon Basin in the Kivalliq region of Nunavut, little is known about the sub-basin distribution of units and structures, making exploration targeting very tenuous. We constructed a geological map of the basement beneath the unconformity by extrapolating exposed features into the subsurface. The new map is constrained by detailed geological, geophysical, and rock property observations of outcrops adjacent to the basin and by aeromagnetic and gravity data over the geophysically transparent sedimentary basin. From rock property measurements, it is clear that the diverse magnetic and density characteristics of major rock packages provide quantitative three-dimensional constraints. Gravity profiles forward modelled in four cross sections define broad synforms of the Amer Belt and Archean volcanic rocks that are consistent with the structural style outside the basin. Major lithotectonic entities beneath the unconformity include: supracrustal rocks of the Archean Woodburn Lake group and Marjorie Hills meta sedimentary gneiss and associated mixed granitoid and amphibolitic gneiss; the Amer Mylonite Zone and inferred mafic intrusions oriented parallel and sub-parallel; other igneous intrusions of 2.6 Ga, 1.83 Ga, and 1.75 Ga vintage; and the <2.3 Ga to >1.84 Ga Amer Group. Four main brittle regional fault arrays (040°-060°, 075°-90°, 120°, and 150°) controlled development and preservation of the basin. The reactivated intersections of such faults along fertile basement units such as the Rumble assemblage, Marjorie Hills assemblage, Nueltin igneous rocks, and Pitz formation are the best targets for uranium exploration. [ABSTRACT FROM AUTHOR]

The Paleoproterozoic Athabasca Basin (Canada) hosts numerous giant unconformity-related uranium deposits. The scope of this study is to establish the pressure, temperature, and composition (P-T-X conditions) of the brines that circulated at the base of the Athabasca Basin and in its crystalline basement before, during and after UO deposition. These brines are commonly sampled as fluid inclusions in quartz- and dolomite-cementing veins and breccias associated with alteration and U mineralization. Microthermometry and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) data from five deposits (Rabbit Lake, P-Patch, Eagle Point, Millennium, and Shea Creek) complement previously published data for the McArthur River deposit. In all of the deposits investigated, fluid inclusion salinity is between 25 and 40 wt.% NaCl equiv., with compositions displaying a continuum between a 'NaCl-rich brine' end-member (Cl > Na > Ca > Mg > K) and a 'CaCl-rich brine' end-member (Cl > Ca ≈ Mg > Na > K). The CaCl-rich brine has the highest salinity and shows evidence for halite saturation at the time of trapping. The continuum of compositions between the NaCl-rich brine and the CaCl-rich brine end-members combined with P-T reconstructions suggest anisothermal mixing of the two brines (NaCl-rich brine, 180 ± 30 °C and 800 ± 400 bars; CaCl-rich brine, 120 ± 30 °C and 600 ± 300 bars) that occurred under fluctuating pressure conditions (hydrostatic to supra-hydrostatic). However, because the two brines were U bearing and therefore oxidized, brine mixing was probably not the driving force for UO deposition. Several scenarios are put forward to account for the Cl-Na-Ca-Mg-K composition of the brines, involving combinations of seawater evaporation, halite dissolution, mixing with a halite-dissolution brine, Mg/Ca exchange by dolomitization, Na/Ca exchange by albitization of plagioclase, Na/K exchange by albitization of K-feldspar, and Mg loss by Mg-rich alteration. Finally, the metal concentrations in the NaCl-rich and CaCl-rich brines are among the highest recorded compared to present-day sedimentary formation waters and fluid inclusions from basin-hosted base metal deposits (up to 600 ppm U, 3000 ppm Mn, 4000 ppm Zn, 6000 ppm Cu, 8000 ppm Pb, and 10,000 ppm Fe). The CaCl-rich brine carries up to one order of magnitude more metal than the NaCl-rich brine. Though the exact origin of major cations and metals of the two brines remains uncertain, their contrasting compositions indicate that the two brines had distinct flow paths and fluid-rock interactions. Large-scale circulation of the brines in the Athabasca Basin and Basement was therefore a key parameter for metal mobility (including U) and formation of unconformity-related U deposits. [ABSTRACT FROM AUTHOR]

The Kiggavik-Andrew Lake structural trend consists of four mineralized zones, partially outcropping, lying 2 km south of the erosional contact with the unmetamorphosed sandstone and basal conglomerates of the Paleoproterozoic Thelon Formation. The mineralization is controlled by a major E-W fault system associated with illite and sudoite alteration halos developed in the Archean metagraywackes of the Woodburn Lake Group. Aluminum phosphate sulfate (APS) minerals from the alunite group crystallized in association with the clay minerals in the basement alteration halo as well as in the overlying sandstones, which underwent mostly diagenesis. APS minerals are Sr- and S-rich (svanbergite end-member) in the sedimentary cover overlying the unconformity, whereas they are light rare earth elements (LREE)-rich (florencite end-member) in the altered basement rocks below the unconformity. The geochemical signature of each group of APS minerals together with the petrography indicates three distinct generations of APS minerals related to the following: (1) paleoweathering of continental surfaces prior to the basin occurrence, (2) diagenetic processes during the burial history of the lower unit of the Thelon sandstones, and (3) hydrothermal alteration processes which accompanied the uranium deposition in the basement rocks and partially overlap the sedimentary-diagenetic mineral parageneses. In addition, the association of a first generation of APS minerals with both detrital cerium oxide and aluminum oxy-hydroxide highlights the fact that a part of the detrital material of the basal Thelon Formation originated from eroded paleolaterite (allochthonous regolith). The primary rare earth element (REE)-bearing minerals (e.g., monazite, REE carbonates, and allanite) of the host rocks were characterized to identify the potential sources of REE. The REE chemical composition highlights a local re-incorporation of the REE released from the alteration processes in the APS minerals of hydrothermal origin. The distinctive geochemical signatures between diagenetic (or sedimentary) and hydrothermal APS minerals suggest a different source material in the Thelon basin than in the Athabasca basin. [ABSTRACT FROM AUTHOR]

ABSTRACT The primary economic uranium (U) mineralization indicators in the Athabasca Basin are the reactivated prominent basement deformation zones, basement alteration halos, and the overlying sandstone alteration halos enveloping the deposit. High-resolution seismic surveys, from the Shea Creek area, are investigated to assess the potential of the surface seismic reflection technique for detecting these key mineralization markers. Four seismic profiles identify ductile to highly brittle deformation features of the basement. One of the brittle deformation features is a southwest-dipping prominent reactivated shear zone comparable to basement structures hosting other known deposits in the basin. The Carswell meteor impact structure is also a conspicuous component of the Shea Creek regional structural regime. The seismic sections identify several features of the impact structure, including recognition that the dimensions of this structure are significantly larger than those estimated by previous geological studies. This larger area includes both the Cluff Lake mine and the Shea Creek U deposits, and it reveals that the basement was considerably disturbed by the impact and suggests the reactivation of the southwest-dipping shear zone. Complex trace analysis of the seismic sections provides detailed information about the lateral changes in the reflectivity properties of the unconformity interval, which is another key zone of interest for uranium exploration. Based mainly on velocity information, several sub-zones of clay alteration and silicification were identified within prominent fracture depth intervals: both in the sandstone and the basement. Thus, this study documents that these primary mineral indicators can be detected by the seismic method. Cross-plots of velocity versus density of well log data identify changes in lithological units such as unaltered basement, fractured/altered basement, unaltered sandstone, clay alterations in sandstone, and silicification in sandstone. [ABSTRACT FROM AUTHOR]

Purpose: To assess health, growth and reproductive success of mammals exposed for multiple generations to levels of radium-226 known to occur in environments surrounding uranium mines and mills in Canada. Methods: The study consisted of a control group and four treatment groups each containing 40 mice (20 males and 20 females) of the CBA/CaJ strain that were continuously exposed to a range of radium-226 levels via drinking water. Breeding was at 8-10 weeks of age and the study was concluded after three breeding cycles. Results: When compared to control mice, constant consumption of drinking water containing 0.012, 0.076, 0.78 and 8.0 Bq/l of radium-226 over four generations of mice did not demonstrably affect physical condition, weight, pregnancy rate, number of pups per litter, sex ratio and bodyweight gain of pups. Between generations, the observed differences in pregnancy rates that were noted in all groups, including controls, seemed to directly correlate with the weight and age of the females at breeding. Conclusions: Based on the endpoints measured on four generations of mice, there is no indication that the consumption of radium-226 via drinking water (at activity concentrations up to 8.0 Bq/l) affects health, growth and reproductive fitness. [ABSTRACT FROM AUTHOR]

This paper asks how Dene (and alongside it non-human) life is connected to the production and circulation of value in the Canadian uranium economy. I examine the ways in which life links up with value during the lifetime of the mine and at the time of a major public inquiry into its health and ecological effects. Against the backdrop of the highly uneven and deeply racialized economy of nuclear production I make two intertwined arguments. First I argue that 'wastage' is a reconfiguration of nature integral to the production of capitalist value in which capital addresses itself directly to the vital processes of (some) living things. Second, at a time when the relational politics that shaped value were being actively subverted by claims publicly advanced by Deline First Nation Dene about cancer death and contamination, I argue that a risk calculation central to the Canada Deline Uranium Table's analysis worked to governmentally secure evidence of wastage and restore the configurations of in/visibility that shaped value production in this economy. [ABSTRACT FROM AUTHOR]

While the number of non-regulatory environmental governance arrangements overseeing mining has been growing in Canada, there remains limited research critically examining Aboriginal peoples' experiences in these emerging institutions. This is especially notable with respect to the sharing of techno-scientific information, often used as a means of enabling Aboriginal peoples' participation and engendering their trust. A qualitative case study of the Northern Saskatchewan Environmental Quality Committee oversight of uranium mining, this research explores how techno-scientific information in the form of risk assessments was socially constructed and discursively employed by government and industry, and how Aboriginal participants responded. Findings illustrate that risk assessments were presented in ways that rendered development as controllable and inevitable, which facilitated dominant political economic agendas and capitalist practices. Aboriginal participants, however, introduced alternative interpretations of risk and sought to claim spaces within this governance institution through underscoring absent uncertainties, and asserting knowledges of global technological failures and local conditions that contradicted scientific reassurances. Aboriginal participants also highlighted the social injustices of development processes in Saskatchewan's north, which shaped their interpretations of risk, raising important questions about the value of these alternative governance institutions for Aboriginal peoples and their environments. [ABSTRACT FROM AUTHOR]

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The Centennial unconformity-related uranium deposit represents the first significant uranium mineralization along the Snowbird tectonic zone in the south-central part of the Athabasca Basin. The deposit is associated with a steeply WNW-dipping contact between the Virgin Schist Group and mylonitic granite of uncertain age. Virgin Schist Group rocks in the deposit area include phyllites, impure quartzite, and quartzite. Medium- to coarse-grained microcline "augen" porphyroclasts characterize the granite. The quartzite, being resistant to weathering, forms a paleotopographic high flanked by a paleotalus which formed prior to Athabasca Group sedimentation. Diabase, petrographically and geochemically similar to the 1.27 Ga Mackenzie dikes, intrudes the mineralized trend along brittle structures in the basement rocks and Athabasca Group. A detailed paragenetic study of the deposit area reveals a protracted history that is related to the episodic reactivation of brittle structures and associated fluid movement along this significant structural corridor. Retrograde metamorphism converted biotite to chamosite at temperatures between 335° to 350°C. Weathering caused the breakdown of microcline and the dissolution of quartz prior to erosion and deposition of the Athabasca Group, which started at about 1750 Ma. Compaction and diagenesis resulted in quartz overgrowths and development of a diagenetic clay assemblage of illite and sudoite at temperatures between 150° and 200°C, which was broadly synchronous with primary mineralization. Clinochlore, euhedral quartz, carbonate, and pyrite was developed after the intru¬sion of the diabase under reducing conditions, primarily at temperatures between 270° to 320°C. Uranium remobilization and alteration of uraninite to coffinite appears to have taken place after the emplacement of the diabase dikes. Kaolinite and uranophane form last in the paragenetic sequence and probably form at relatively low temperatures. [ABSTRACT FROM AUTHOR]

The introduction of electrodynamic pulse disaggregation (EPD) as a sample preparation tool, traditionally dominated by mechanical (jaw-crusher) fragmentation (MF), begs the need for a comparison of element concentrations and isotopic ratios results from leaching of samples prepared by each of these methods. With this in mind, element concentrations and Pb isotope ratios were measured for samples from the Cigar Lake unconformity-hosted uranium deposit, Athabasca Basin, Canada using a weak acid leach (2% HNO 3) digestion. Six sample preparation methods (SPMs) were established from MF and EPD: SPM1) MF samples sieved to 0.5–1.18 mm; SPM2) MF samples sieved to > 1.18 mm, shaken with DI water to extract a clay-rich water, clay-rich water dried; SPM3) dried aliquot of water after EPD; SPM4) < 2 μm clay-sized mineral fraction separated from settled EDP water; SPM5) EPD samples sieved to < 0.5 mm; and SPM6) EPD samples sieved to 0.5–1.18 mm. Pathfinder elements for unconformity-hosted uranium deposits (U, Pb, Th, Ni, Co, As, Cu, and Zn) show increasing concentrations with SPMs that produced a higher portion of the clay-sized mineral fraction, up to 15.92 μg/g U, 40.91 μg/g Th, and 4.85 μg/g Pb. Sample preparation methods 1, 2, and 4 have the most radiogenic Pb isotope ratios (207Pb/206Pb = 0.10–0.40), with least radiogenic ratios in other SPMs ranging from 207Pb/206Pb = 0.23 to 0.82. The 207Pb/206Pb values, combined with 206Pb/204Pb and 207Pb/204Pb, indicate that an increase in common Pb has diluted the radiogenic components for the least radiogenic fractions. MF and EPD both offer benefits for preparing samples for weak acid leach but results from this study show that clay extracted by EPD (SPM4) is the optimal method, producing higher pathfinder element contents and radiogenic Pb values. This study demonstrates that SPMs can result in variable mixes of the original minerals, which affects element concentrations and Pb isotope ratios that are extracted. The modification of geochemical results via SPMs, with the leaching of common Pb unrelated to ore system processes and changes to pathfinder elements concentrations, has implications for using weak acid leach and other partial leaches in exploration in sandstone hosted systems for all mineral commodities. The generation of unreliable geochemical results decreases the effectiveness of exploration programs, potentially missing positive anomalies and overall increases the cost associated with ore deposit discovery, offsetting the added costs of SPMs for geochemical surveys. • Mechanical fragmentation and electrodynamic pulse disaggregation sample preparation methods for weak acid leach (2% HNO 3). • Sample preparation methods can affect element concentrations and Pb isotope ratios that are extracted by weak acid leach. • Clay extracted by electrodynamic pulse disaggregation is the optimal method for unconformity-hosted uranium exploration programs. [ABSTRACT FROM AUTHOR]

Historic data from many countries demonstrate that on average no more than 50–70% of the uranium in a deposit could be mined. An analysis of more recent data from Canada and Australia leads to a mining model with an average deposit extraction lifetime of 10±2years. This simple model provides an accurate description of the extractable amount of uranium for the recent mining operations. Using this model for all larger existing and planned uranium mines up to 2030, a global uranium mining peak of at most 58±4ktons around the year 2015 is obtained. Thereafter we predict that uranium mine production will decline to at most 54±5ktons by 2025 and, with the decline steepening, to at most 41±5ktons around 2030. This amount will not be sufficient to fuel the existing and planned nuclear power plants during the next 10–20years. In fact, we find that it will be difficult to avoid supply shortages even under a slow 1%/year worldwide nuclear energy phase-out scenario up to 2025. We thus suggest that a worldwide nuclear energy phase-out is in order. If such a slow global phase-out is not voluntarily effected, the end of the present cheap uranium supply situation will be unavoidable. The result will be that some countries will simply be unable to afford sufficient uranium fuel at that point, which implies involuntary and perhaps chaotic nuclear phase-outs in those countries involving brownouts, blackouts, and worse. [ABSTRACT FROM AUTHOR]

Abstract: Sandstone-hosted unconformity-related U deposits in the Athabasca Basin at McArthur River Zone 4 and Maurice Bay as well as barren alteration systems at Wheeler River Zone “K” and Spring Point are surrounded by an outer, peripheral zone of illite and an inner, central zone of chlorite alteration. The oxidation state of Fe determined by 57Fe Mössbauer spectroscopy of illite, sudoite, and clinochlore from these systems indicates that pre-ore illite contains mostly Fe3+ (Fe3+/ΣFe=0.77–1.00), reflecting formation from a predominantly oxidizing basinal fluid. Lower Fe3+/ΣFe ratios are recorded by late pre-ore sudoite and clinochlore occurring near faulted unconformities, consistent with the contribution to the chlorites from reducing basement-derived fluids. Sudoite and clinochlore in the alteration halo of barren systems are more reduced (Fe3+/ΣFe median=0.3–0.4) than sudoite from mineralized systems (Fe3+/ΣFe median=0.45–0.55). Sudoite from both systems becomes broadly more oxidized with increasing distance from the fault zone. Variations in the Fe3+/ΣFe ratios of sudoite and clinochlore support a mechanism in which Fe2+ transported by reducing basement-derived fluids is partially oxidized to Fe3+ by basinal fluids prior to incorporation into the chlorite. Thus, scarcity of oxidizing U-bearing basinal fluids available for interaction with reducing basement fluids is a critical factor precluding U mineralization in barren systems. Trends of decreasing Fe3+/ΣFe ratios in sudoite coupled with decreasing 207Pb/206Pb ratios of leachable Pb can be used as geochemical vectors to the sites of potential U mineralization. [Copyright &y& Elsevier]

The Metal Mining Effluent Regulations (MMER) took effect in 2002 and require most metal mining operations in Canada to complete environmental effects monitoring (EEM) programs. An 'effect' under the MMER EEM program is considered any positive or negative statistically significant difference in fish population, fish usability, or benthic invertebrate community EEM-defined endpoints. Two consecutive studies with the same statistically significant differences trigger more intensive monitoring, including the characterization of extent and magnitude and investigation of cause. Standard EEM study designs do not require multiple reference areas or preexposure sampling, thus results and conclusions about mine effects are highly contingent on the selection of a near perfect reference area and are at risk of falsely labeling natural variation as mine related 'effects.' A case study was completed to characterize the natural variability in EEM-defined endpoints during preexposure or baseline conditions. This involved completing a typical EEM study in future reference and exposure lakes surrounding a proposed uranium (U) mine in northern Saskatchewan, Canada. Moon Lake was sampled as the future exposure area as it is currently proposed to receive effluent from the U mine. Two reference areas were used: Slush Lake for both the fish population and benthic invertebrate community surveys and Lake C as a second reference area for the benthic invertebrate community survey. Moon Lake, Slush Lake, and Lake C are located in the same drainage basin in close proximity to one another. All 3 lakes contained similar water quality, fish communities, aquatic habitat, and a sediment composition largely comprised of fine-textured particles. The fish population survey consisted of a nonlethal northern pike ( Esox lucius) and a lethal yellow perch ( Perca flavescens) survey. A comparison of the 5 benthic invertebrate community effect endpoints, 4 nonlethal northern pike population effect endpoints, and 10 lethal yellow perch effect endpoints resulted in the observation of several statistically significant differences at the future exposure area relative to the reference area and/or areas. When the data from 2 reference areas assessed for the benthic invertebrate community survey were pooled, no significant differences in effect endpoints were observed. These results demonstrate weaknesses in the definition of an 'effect' used by the MMER EEM program and in the use of a single reference area. Determination of the ecological significance of statistical differences identified as part of EEM programs conducted during the operational period should consider preexisting (background) natural variability between reference and exposure areas. Integr Environ Assess Manag 2013; 9: 155-163. © 2012 SETAC [ABSTRACT FROM AUTHOR]

Uranium exploration and mining make widespread use of gamma-ray logs to determine ore-grade distribution in situ. Attenuation, scattering, and uncollimated detectors all degrade the signal, hampering accuracy. We deconvolve their effects from the measured logs by space-domain processing with the aid of a function that takes account of detector length and uranium ore-zone thickness. The output quantifies uranium grade by zones of specified location and thickness. With this method, thin zones of very high grade can be used for calibration. Illustrative data come from model pits in Australia, Canada, and the USA. [ABSTRACT FROM AUTHOR]

The article discusses a court case relating to the judicial review of a licence renewal decision by the Canadian Nuclear Safety Commission (CNSC) regarding a uranium mine and mill operating licence held by AREVA Resources Canada Inc. The case centered on the state's legal duty under Canadian constitutional law to consult with aboriginal groups when planning any action which could adversely affect existing Aboriginal and Treaty rights.

URANIUM MINERS IN ELLIOT LAKE went on a wildcat strike in 1974 to protest their occupational health concerns on the job after a spike in cancer cases. They learned that the provincial government had known of the poor working conditions causing their illnesses, but had not informed them of the dangers or acted to improve their situation. As a result of union and political pressure, the Ontario government created the Ham Commission to investigate and make recommendations. Its hearings revealed the industry's scandalous conditions, and its report eventually resulted in the Ontario Health and Safety (OHS) Act in Ontario. It did not cover the miners until 1984, so they worked through their internal health and safety committees to gain improvements in the work environment. Others have discussed this situation in relation to the emergence of the OHS and environmental movements. This paper discusses the events in terms of the mine owners' attitudes towards their employees, the industry's relationship to governments, and the impact of the uranium mining industry (part of the nuclear industry) on the local community and environment. [ABSTRACT FROM AUTHOR]

The Screening Level Concentration (SLC) approach was used to derive Lowest Effect Level (LEL) and Severe Effect Level (SEL) concentrations for nine metals (As, Cr, Cu, Pb, Mo, Ni, Se, U and V) and three radionuclides (226Ra, 210Pb, and 210Po) released to the aquatic environment during the mining and milling of uranium ore. This method was chosen because it allowed for the best use of the considerable historical and current data collected for diverse purposes in the uranium mining and milling regions of Canada (20,606 data points used in the analysis). Except for Cr, all the LELs derived in this study using the weighted method and published sediment quality guidelines (SQGs) were highly reliable (> 85%) in predicting sites unimpacted by uranium mining/milling defined as sites where reductions in the abundance and species richness of benthic invertebrate communities were < 20%. The derived SEL values and corresponding published SQGs (with the exception of Ni) were not reliable predictors (≤60%) of severe impacts on benthic invertebrate communities when severe impacts are defined as a reduction in abundance and species richness ≥40%. Most of the severely impacted sites had sediment contaminant concentrations well below the SEL values. It is concluded that LELs derived using the weighted method can reliably be used in ecological risk assessments as concentrations below which adverse effects on benthic invertebrate communities are not expected. In contrast, it is recommended that SELs not be used in assessments of uranium mining/milling activities as concentrations above which adverse effects are anticipated. [ABSTRACT FROM AUTHOR]

(1) Canada - Right of Appeal of Arbitration Award Questioned (2) United States - Canadians Sue Kazakhstan Uranium for of Contract (3) United States - Partition of Mineral Estate Questioned (4) United States - Uranium Mine Toxic Tort Verdict Rendered (5) United States - Surface Mine Reclamation Fines Imposed on Operator While Mine Owners Squabble as to Liability (6) United States - Engineer Loses Professional Defamation Action (7) U. S. Virgin Islands - Class Action Approved for Aluminium Plant Dust Claim [ABSTRACT FROM AUTHOR]

The basement-hosted Bong uranium deposit in the Kiggavik region is associated with a broad hydrothermal alteration halo characterized by an inner illite-rich zone and an outer chlorite-rich zone. The uranium-bearing zones characterized by intense illite alteration yield high δ56Fe and δ26Mg values relative to the host rocks, with average whole-rock values of δ56Fe = 0.58 ± 0.15‰ and δ26Mg = 0.61 ± 0.29‰, and clay-size fraction values of δ56Fe = 0.51 ± 0.20‰ and δ26Mg = 0.82 ± 0.09‰. These isotopic values correlate with a decrease in average Fe2+ concentrations (0.47 versus 2.30 mol% Fe2+ in least-altered hosts). The high δ26Mg values reflect intense illite alteration, which preferentially incorporated heavier magnesium isotopes during alteration of both the ore zones and an upper hematite-altered horizon. Although the clay alteration with high δ56Fe and δ26Mg values coincides with the main uranium-bearing zone, the δ56Fe signatures reflect multiple stages of alteration and mineralization. The high δ56Fe values and lower Fe2+ contents of the uranium-bearing zones support leaching of Fe2+ (aq) enriched in lighter iron isotopes. Sequential leach δ56Fe experiments also indicate that formation of fine-grained iron oxides/hydroxides with positive δ56Fe values (+0.23 to +0.60‰) in late chemical fronts enhanced the primary positive δ56Fe signatures recorded in ore zones. Near surface samples with similar isotopic signatures provide clues to buried mineralization and support structural disruption of the systems after primary mineralization. Distal geochemical expressions of this system may include enrichment in iron contents with negative δ56Fe values and/or negative δ26Mg whole-rock or clay-size fractions values, reflecting precipitation of the isotopically light iron and magnesium leached during hydrothermal alteration. Although more costly to process, sequential leach δ26Mg or δ56Fe analyses produced greater variance in the ore zones relative to background values and removed anomalous values from carbonate minerals. Isotopic analyses of the clay-size fraction produced results comparable to the final digestion in the sequential leach process but this method in particular requires greater understanding the mineralogical controls on the isotopic signatures. [Display omitted] • Application of iron and magnesium isotope methods to hydrothermal uranium deposits • Complex hydrothermal fluid history revealed through iron and magnesium isotopes • Quantifying fluid-rock and redox reactions in the formation of unconformity-related uranium deposits [ABSTRACT FROM AUTHOR]

Focuses on the presence of radioisotopes produced by a uranium mine in Saskatchewan detected in the area's food chain. Analysis of radionucleotides in caribou; Calculation of radioisotope contamination based on samples taken from caribou body parts; Relevance of the findings for future evaluation of uranium mining impacts on critical food chains.

The article presents information on a case study on women's participation in the anti-uranium mining movement in Nova Scotia, Canada in 1981-1983. The anti-toxic movement was a loose coalition of organizations fighting against local hazardous waste disposal or production facilities. Women predominated in its leadership roles. The gendered recruitment to this movement is explained by a fit between the community health focus of its issues and women's traditional role-the motherhood effect. The fact that women played a central organizational role is explained in two ways. Women have greater structural availability than men do; that is, they are less likely to be in the labor force. Women's local networks, based on ties of kinship and domestic labor, provide more powerful support than do men's. Literature on the anti-toxic movement offers a model of these women as housewife activists, whose politics are embedded in the sphere of the private, the concrete and the particular. The movement has also been credited with the creation of a new sort of feminist.