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Paradis S.,Geological Survey of Canada | Keevil H.,University of British Columbia | Keevil H.,Colorado School of Mines | Simandl G.J.,British Columbia Ministry of Energy and Mines | Raudsepp M.,University of British Columbia
Mineralium Deposita | Year: 2015

Many carbonate-hosted sulphide deposits in the Salmo district of southern British Columbia have near-surface Zn- and Pb-bearing iron oxide-rich gossans. The gossans formed when carbonate-hosted, base metal sulphides were subjected to intense supergene weathering processes and metals were liberated by the oxidation of sulphide minerals. Two types of supergene carbonate-hosted nonsulphide deposits, direct replacement (‘red ore’) and wallrock replacement (‘white ore’), are present in the Salmo district. The direct replacement deposits formed by the oxidation of primary sulphides; the base metals passed into solution and were redistributed and trapped within the space occupied by the oxidized portion of the sulphide protore. Depending on the extent of replacement of the sulphides by Zn-, Pb- and Fe-bearing oxides, silicates, carbonates and phosphates, the resulting ore can be called ‘mixed’ (sulphides and nonsulphides) or simply ‘nonsulphide’. The wallrock replacement deposits formed when base metals liberated by the oxidation of sulphides were transported by circulating supergene solutions down and/or away from the sulphides to form wallrock replacement deposits. The direct replacement nonsulphide zones of the Salmo district overlay the sulphide bodies in which they replaced the sulphides and carbonates, forming large irregular replacement masses, encrustations and open-space fillings. They consist predominantly of hematite, goethite, hemimorphite [Zn4Si2O7(OH)2·H2O], minor hydrozincite [Zn5(CO3)2(OH)6], cerussite [PbCO3] and traces of willemite [Zn2SiO4]. The wallrock replacement zones consist mainly of hemimorphite with local occurrences of iron oxides, hopeite [Zn3(PO4)2·4H2O] and tarbuttite [Zn2(PO4)(OH)]. No remnants of sulphides were observed in the replacement zones. The Salmo nonsulphide deposits were formed by prolonged weathering of Mississippi Valley-type (MVT) mineralization that underwent dissolution and oxidation of the pyrite, sphalerite and galena protore. The weathering also leached out highly mobile Zn, less mobile Pb and left behind the iron oxides, precipitating Zn and Pb silicates within the protore or at a distance from the protore. © 2015 Her Majesty the Queen in Right of Canada Source


Walsh W.,British Columbia Ministry of Energy and Mines | Tu A.,BC Hydro
Transactions - Geothermal Resources Council | Year: 2014

Although most commonly associated with young volcanic terranes and active hot springs, sedimentary basins hold tremendous geothermal potential. Several factors make many sedimentary basins ideal locations to explore for geothermal energy: low thermal conductivity of sedimentary rocks results in higher than average geothermal gradients; porous and permeable regional aquifers are conducive to the production of geothermal fluids; and existing oil and gas exploration results are available to characterize and evaluate potential fields. The Clarke Lake gas field south of the city of Fort Nelson in northeastern British Columbia, Canada, is hosted by Middle Devonian carbonate rocks that have long been known to exhibit remarkable permeability and temperatures in excess of 110°C. This permeable dolomite aquifer is controlled by the diagenetic alteration of the original depositional trend of reef facies in the Keg River through Slave Point formations, and is over 200m at its thickest. Estimates of the recoverable thermal energy within the aquifer at Clarke Lake using a Volume Method Monte-Carlo model indicate the resource is significant in size (mean 10.1 X 1014 kJ; standard deviation 3.2 X 1014 kJ). Using binary geothermal technology, this thermal energy can be used to generate electricity. It is estimated that purpose-built wells would be able to access enough thermal energy to generate more than 1MW of electricity each. Geothermal plants could be supplied by multiple directional wells to provide greater capacity than is capable from a single well. The resource assessment indicates that the Clarke Lake field could be used to generate between 12 to 74 MW (mean 34MW; standard deviation 10.8MW) of electricity. Copyright © (2014) by the Geothermal Resources Council. Source


Simandl G.J.,British Columbia Ministry of Energy and Mines | Simandl G.J.,University of Victoria
Mineralium Deposita | Year: 2014

China started to produce rare earth elements (REEs) in the 1980s, and since the mid-1990s, it has become the dominant producer. Rare earth element export quotas first introduced by the Chinese government in the early 2000s were severely reduced in 2010 and 2011. This led to strong government-created disparity between prices within China and the rest of the world. Industrialized countries identified several REEs as strategic metals. Because of rapid price increases of REE outside of China, we have witnessed a world-scale REE exploration rush. The REE resources are concentrated in carbonatite-related deposits, peralkaline igneous rocks, pegmatites, monazite ± apatite veins, ion adsorption clays, placers, and some deep ocean sediments. REE could also be derived as a by-product of phosphate fertilizer production, U processing, mining of Ti-Zr-bearing placers, and exploitation of Olympic Dam subtype iron oxide copper gold (IOCG) deposits. Currently, REEs are produced mostly from carbonatite-related deposits, but ion adsorption clay deposits are an important source of heavy REE (HREE). Small quantities of REE are derived from placer deposits and one peralkaline intrusion-related deposit. The ideal REE development targets would be located in a politically stable jurisdiction with a pro-mining disposition such as Canada and Australia. REE grade, HREE/light REE (LREE) ratio of the mineralization, tonnage, mineralogy, and permissive metallurgy are some of the key technical factors that could be used to screen potential development projects. As REEs are considered strategic metals from economic, national security, and environmental points of view, technical and economic parameters alone are unlikely to be used in REE project development decision-making. Recycling of REE is in its infancy and unless legislated, in the short term, it is not expected to contribute significantly to the supply of REE. © 2014, Her Majesty the Queen in Right of Canada. Source


English J.M.,University of Victoria | Mihalynuk M.G.,British Columbia Ministry of Energy and Mines | Johnston S.T.,University of Victoria
Canadian Journal of Earth Sciences | Year: 2010

The northern Cache Creek terrane in the Canadian Cordillera includes a subduction complex that records the existence of a late Paleozoic - Mesozoic ocean basin and provides an opportunity to assess accretionary processes that involve the transfer of material from a subducting plate to an upper plate. Lithogeochemical data from basaltic rocks indicate that the northern Cache Creek terrane is dominated by two different petrogenetic components: (1) a dominant suite of subalkaline intrusive and extrusive rocks mostly of arc affinity and (2) a volumetrically less significant suite of alkaline volcanic rocks of within-plate affinity. The subalkaline intrusive and extrusive rocks constitute a section of oceanic lithosphere that is interpreted to have occupied a fore-arc position during the Late Triassic and Early Jurassic before it was accreted during collisional orogenesis in the Middle Jurassic. Alkaline volcanic rocks in the northern Cache Creek terrane are stratigraphically associated with carbonate strata that contain Tethyan fauna that are exotic with respect to the rest of North America; together, they are interpreted as remnants of oceanic seamounts and (or) plateaux. The volcanic rocks are a minor component of the carbonate stratigraphy, and it appears that the majority of the volcanic basement was either subducted completely at the convergent margin or underplated at greater depth in the subduction zone. In summary, accretion in the northern Canadian Cordillera occurred principally by the accretion of island arcs and emplacement of fore-arc ophiolites during collisional orogenesis. The transfer of oceanic sediments and the upper portions of oceanic seamounts from the subducting plate to an accretionary margin accounts for only small volumes of growth of the upper plate. Source


Johnson M.F.,National Energy Board | Walsh W.,British Columbia Ministry of Energy and Mines | Budgell P.A.,National Energy Board | Davidson J.A.,National Energy Board
Society of Petroleum Engineers - Canadian Unconventional Resources Conference 2011, CURC 2011 | Year: 2011

The Horn River Basin of northeastern British Columbia, Canada, contains natural gas in three Devonian shale units. Isopachs, depths, and net-to gross-pay ratios were determined from well logs for the Muskwa, Otter Park, and Evie Shales and then gridded. Pressure gradients were determined from well test and production data and then gridded into a single grid shared between shales. Because grid points were shared between each grid, volumetric and adsorbed gas equations could be integrated into each grid point. Static values or distributions could then be applied to equation variables and Monte Carlo simulations run to determine probabilistic gas in place (GIP) and marketable resources for each grid point, which were then summed for each shale. Grid points for the isopach and depth maps were treated as static values in the equations while net-to-gross and pressure gradient grid points became most likely values in Beta distributions where end points were assigned using regional low and high values. Most non-mapped variables in the equations were filled with Beta distributions based on typical values in the area and then applied across the basin without any local variations. On each distribution, whether based on mapped or unmapped variables, a second, overlying distribution was applied on a basin scale. This made entire iterations run a full range from pessimistic to optimistic. A few non-mapped variables in the equations were given static values. Recoverable gas resources were estimated by applying a recovery factor to free GIP estimates. Recoverable volumes from adsorbed GIP estimates were determined from a recovery factor applied to the portion of gas that would desorb during production as pressure decreased to the assumed well abandonment pressure. To determine marketable gas, gas impurities and fuel gas that would be used for processing and transport were estimated and subtracted from the recoverable estimates. Further, certain lower quality areas of the basin were excluded from the assessment, based on a low likelihood of being developed. The Horn River Basin shales are estimated to contain 10 466 10 9m 3 (372 Tcf) to 14 894 10 9m 3 (529 Tcf) of GIP with the expected outcome of 12 629 10 9m 3 (448 Tcf). The marketable resource base is expected to be 1 715 10 9m 3 (61 Tcf) to 2 714 10 9m 3 (96 Tcf), with an expected outcome of 2 198 10 9m 3 (78 Tcf). ©Her Majesty the Queen in Right of Canada 2011. Source

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