Fluorspar POSTER ROUNDUP 09 ...
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Suggested reference style: Simandl, G.J. (2009): (Put a really good eye- catching and relevant graphic FLUORSPAR MARKET REVIEW AND SELECTED FLUORITE DEPOSITS IN BRITISH COLUMBIA, CANADA George J. Simandl 1,2 Suggested reference style: Simandl G.J.(2009): Fluorspar market and selected fluorite-bearing deposits, British Columbia, Canada. Geofile 2009-03. Poster. British Columbia Ministry of Energy and Mines; HF and AlF 3 Metallurgical Other 0.00 50.00 100.00 150.00 200.00 250.00 300.00 350.00 400.00 1900 1920 1940 1960 1980 2000 2020 US$ / tonne 0 1 2 3 4 5 6 1900 Year Million tonnes 2000 1980 1960 1940 1920 2020 Introduction Fluorspar is the commercial term for fluorite (CaF ) Fluorite contains 51.1% Ca and 48.9% F. Collector specimens occur as cubes and octahedrons. Typical fluorspar ores are massive , disseminations, or form layered crusts, globular and botroidal aggregates and cox-comb textures. Other sources of F are cryolite and phosphate rock. Cryolite (Na AlF ) was historicallymined in Greenland. Due to environmental pressure, F compounds are now recovered during the processing of sedimentary phosphates. Fluosilic acid (H SiF ) is one of these compounds. environmental regulations suggest that this acid will be increasingly converted into Al- or Ca-fluorides, cryolite, or H. Phosphate rock reserves in the USA alone contain 370 million tonnes of F. 2. 3 6 2 6, used in water fluoridation, Strict Fluorspar is used largely in the manufacturing of fluorocarbons for refrigerants, foam products, polytetrafluoroethylene (“Teflon”) and other fluoropolymers. Petroleum alkylation, glass, medical, agricultural and metallurgical uses also represent important markets. Demand for fluorspar in the manufacture of fluoropolymers and fluoroelastomers, including partially fluorinated polymers or copolymers is growing. Over 70% of fluorspar used in developed countries is transformed into HF products, while in developing countries over 65% of fluorite is used in steel-making. Fluorspar uses in USA are summarized on Aluminum fluoride (AlF ) and synthetic cryolite, derived largely from acid grade fluorspar, are the main F compounds used in aluminum (Al) smelting. The growth of this market is favoured by increasing demand for Al in the automotive industry, but it is counterbalanced by improvements in smelting technology, increased recycling of both, Al and F, and by increased use of AlF derived from fluosilic acid. Fluorspar products are sold to steel mills, cement plants, foundries, glass and ceramic plants, and welding rod manufacturers where they are used as fluxes. 3 3 Figure 1. Fluorspar Production and Prices Fluorspar production first exceeded 1 million t/year during World War II It peaked at 5.56 million t/year in 1989 and then bottomed out at 3.75 million t/year in 1994 due to restrictions on the use of fluorocarbons (particularly CFCs) related to the Montreal Protocol.. The market stabilized in the 4.2 - 4.5 million t/year range between 1997 and 2000. By 2004 fluorspar production consistently exceeded 5 million t/year (US Geological Survey, 2007). The variation in price of fluorspar in the USA over the last 100 years is shown on (Figure 1). Figure 2. Figure 1. Fluorspar uses in USA. Data from Miller (2008b). Major Fluorspar-producing Countries In 2007 world fluorspar production was 5.59 million t ( . China, at 3.2 million t, is the largest fluorspar producing country ( and strongly influence fluorspar prices. It is followed by Mexico (933 000 t), Mongolia (380 000 t), South Africa (285 000 t), Russia (180 000 t), Spain (155 500 t), Namibia (118 000 t) and Morocco (95 000 t). Recently, China has been diverting an increased proportion of its fluorspar output to domestic production of HF and thus its fluorspar exports shrinked. Prices of fluorspar concentrates have risen in terms of US dollars (Figure 2), creating opportunities for fluorspar producers outside of China. Since the summer of 2007, economic growth in China slowed down and it remains to be seen if China will maintain its export restrictions.. Miller, 2008b) s Figure 4) Figure 4. World metallurgical and acid grade fluorspar production by country for the year 2007. Data from Miller (2008b). 0 500 1000 1500 2000 2500 3000 3500 Brazil China 1000 metric tonnes India Kenya Mexico Mongolia Morocco N. Korea Namibia Pakistan Russia S. Africa Thailand Turkey UK Other Spain Tajikistan Acid grade Metallurgical & acid grades Metallurgical grade Germany Figure 7: Fluorite disseminated in trachytic meta-tuff, Rexspar deposit, central British Columbia, Canada. Fluorite is purple to almost black. Weathered sulphides give rock rusty-brown appearance (fine division on the scale = 1mm). Figure 6: Crackle breccia. Dark purple, fine-grained fluorite fills fractures and replaces pale gray limestone. Rock Canyon Creek deposit, southeastern British Columbia, Canada. Figure 5: Coarse fluorite (pale to dark green) cementing a breccia and replacing fragments of the host rock. Rock Candy mine, southern British Columbia, Canada. Figure 8: Fluorite vein grade model can be used in mineral potential evaluations and in early screening of fluorite development projects. From Orris (1992). Figure 9: : Fluorite vein tonnage model can be used in mineral potential evaluations and in early screening of fluorite development projects. From Orris (1992). Figure 10: Underground Fluorspar Mine located near Potosi, Mexico; photo used with permission of MEXICHEM. Figure 11: Large open pit fluorite mine, within the giant Vergenoeng fluorite - iron oxide - fayalite pipe, South Africa. White pick-up truck for scale. Photo used with permission of Vergenoeg Mining Company Ltd. 23 44 64 0 10 20 30 40 50 60 70 80 90 100 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 0 N=25 Fluorite grade (% CaF ) 2 Proportion of deposits 0.04 0.68 11 0.0016 0.0063 0.025 0.1 0.4 1.6 6.3 25 100 400 1600 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 0 N=25 Million tonnes (CaF ) 2 Proportion of deposits Figure 12: Acid grade fluorspar concentrate; particles are less than 1 mm in size. Photo used with the permission of the MEXICHEM. Figure 13: Metallurgical grade fluorspar concentrate. The ruler is in inches and centimeters for scale. Photo used with the permission of the MEXICHEM Figure 14 Geographic location of known fluorspar reserves (data reported by Miller 2008a). Figure 16 Ratios of “reserves” and “reserve base” to the 2007 yearly production can be used as crude relative indicators of fluorspar availability. The ratio involving reserves looks at near term availability and ratio involving reserve base provide longer term estimate. The accuracy and precision of these estimates are ultimately dependent on the quality of the database (in this case we use the reserves and reserve base data from Miller (2008a) and yearly productions as reported by Miller (2008b)). Figure 2. World Fluorspar production Figure 3. Fluorspar prices in USA. Fluorspar Geology Montroc Le Moulinal Fluorite occurs in variety of geological settings. It is the only (or the main) ore mineral in classical deposits: such as: Las Cuevas, Encantada-Buenavista, El Triangulo, (Mexico); St. Lawrence pluton-related veins and the Rock Candy Mine (Canada); El Hamman veins (Morocco) and Le Burc, and Trebas deposits (France). Fluorite also occurs in association with other industrial minerals or metals in carbonatites and alkaline complexes, Mississippi Valley type Pb-Zn-fluorite-barite deposits, fluorite-barite-(Pb-Zn) veins, hydrothermal Fe (± Au, ±Cu) and REE deposits, precious metal concentrations, fluorite/metal-bearing skarns, Sn-polymetallic greissen-type deposits, zeolitic rocks and uranium deposits. At first glance the co-production of fluorite with metals appears an attractive proposition but in most cases such association represents increased capital and processing costs. From the engineer's point of view, economic fluorite deposits occur as simple or composite veins, stockworks and breccia zones , diatreme pipes, disseminations or other features where fluorite occurs as open space fillings (such as in karst). Replacement-type, residual (unconformity-related) and stratiform bodies are also known to form high-grade deposits. Vein-type deposits have historically supplied the majority of the fluorspar market. Grade and tonnage curves (Figures 8 and 9 ) cover vein-type deposits. These curves were originally produced for mineral potential assessments, but they can be used during the early screening of exploration projects. The vertical axis of these diagrams extends from zero to one. The horizontal axis represents either tonnage or grade (% CaF ). For example, from Figure 8 we can determine that 90% (0.9 on the vertical scale) of fluorite vein-type deposits have grades ( CaF . content) higher than 23%. Half (0.5 on the vertical scale) of these deposits grade higher than 44% CaF . Less than 10% (0.1 on the vertical scale) of the deposits have a grade higher than 64 % CaF . The same approach is used to interpret the High grade, large tonnage deposits are preferred targets. The shape, orientation, depth of mineralization and geotechnical parameters determin if fluorspar is extracted by surface or underground mining (Figure 10 and 11). For large, medium to low grade ore deposits containing minerals with similar properties to fluorspar, the processing circuit are complex. Heavy-media separation, followed by differential flotation , combined with other methods are common practice. Fine-grain flotation concentrates (or dust) may be pelletized or briquetted to satisfy consumer needs. Deposits, able to provide coarse and high-grade fluorite-rich ores (or usable concentrate requiring simple metallurgical processing) are primary exploration targets, but other large tonnage, lower grade deposits are being investigated. The presence of metallic minerals within fluorite ore may improve or impair the economic viability of a deposit. If metallurgical and economic parameters are satisfied, fluorspar is recovered as by-product of metal mining (e.g. Pb-Zn veins, Mississippi Valley type Pb-Zn deposits,, barite-fluorite, REE-fluorite and uranium-fluorite deposits), where fluorite accounts for 10% or more of the ore. Fluorite is also recovered from tailings associated with historic mines in Mexico and Europe. 2 2 2, 2 (Figures 5 and 6) (Figure 7) Figure 9. Fluorite Ores and Grades of Concentrate The texture, mineralogy and chemistry of the mine-run are reflected in the silica, sulphur, calcite and minor and trace element content of fluorite concentrates, affecting the marketability of products.Concentratess are subdivided into ceramic, metallurgical and acid grades (Harben, 1999; British Geological Survey, 2005). is commonly fine-grained and subdivided to No.1 product - 95-96% CaF , < 3% SiO <0.12 ferric oxides, low calcite content and traces of Pb and Zn and No.2 product contains 85% to > 90% CaF concentrate must contain more than 97% CaF , < 1.5% SiO , 0.03 0.10% S (as sulphide or free S), <12 ppm As, 100 - 550 ppm P, plus low concentrations of Pb, Cd, Be, CaCO and moisture (Harben, 1999). This grade is produced by the flotation process so its particle size is typically 100 mesh or lower concentrate must contain > 80% CaF < 15% SiO , and the material must pass through a 1.0 to 1.5 inch screen while less than 15% of that material should pass through a 1/16th inch screen (Harben, 1999). In the USA, metallurgical grade fluorspar needs to have over 60 effective % fluorspar ({%CaF - [2.5 x %SiO ] } > 60). Fines meeting or slightly exceeding chemical specifications of metallurgical grade products may be pelletized or briquetted and used as a substitute for the traditional “gravel-type” fluorspar products seen in several segments of the metallurgical industry (Figure 13). While acid grade concentrate is considered by users as the highest quality product (> 97% CaF ), it is commonly produced from lower grade ore than metallurgical grade concentrate. This is possible because acid-grade concentrate does not have to be coarse-grained (fine-grinding and flotation can be used for upgrading). To produce metallurgical grade (“gravel-type”) rather exceptional deposit is required, or the ore must be extracted by selectivemining To preserve coarse fluorite particles, the mine run is only crushed, sorted (sometimes by hand or upgraded using a heavy media separation circuit), screened, dedusted and dried before packing and shipping. 2 2, 2. 2 2 3 2, 2 2 2 2 , .. Ceramic grade Acid grade Metallurgical grade (Figure 12). Fluorspar Availability The availability of fluorspar , based on a compilation of Miller (2008a) is summarized in Figures 14 and 15. Data probably incorporate a large margin of error (it is highly unlikely that world “reserves” are exactly 50% of the world “reserve base”). US Geological Survey (2008) definitions of the terms “resources”, “reserves” and “reserve base” are defined below. The term “resource” refers to “a concentration of naturally occurring solid, liquid, or gaseous material in or on the Earth's crust in such form and amount that economic extraction of a commodity from the concentration is currently or potentially feasible”. The term “reserve base” refers to “an identified resource that meets specified minimum physical and chemical criteria related to current mining and production practices, including those for grade, quality, thickness, and depth. The reserve base is the in place demonstrated (measured plus indicated) resource from which reserves are estimated. It may encompass those parts of the resources that have a reasonable potential for becoming economically available within planning horizons beyond those that assume proven technology and current economics. The reserve base includes those resources that are currently economic (reserves), marginally economic (marginal reserves), and some of those that are currently sub-economic (subeconomic resources)”. “Reserves” are “a part of the reserve base which could be economically extracted or produced at the time of determination. The term reserves need not signify that extraction facilities are in place and operative. Reserves include only recoverable materials”. South Africa stands out because its reserves and reserve base could sustain the 2007-level production (295 000 t/year) for 139 and 275 years respectively. Morocco is a major producer, yet Miller (2008a) does not have information regarding its fluorspar reserves or reserve base. Russia’s reserves are described as “moderate”. In the absence of better data we have extrapolated Russia's reserves to be half the size of its reserve base. Some other fluorspar producing countries listed by Miller (2008b), not shown on Figure 16 for similar reasons, are Brazil (63 700 t), Iran (65 000 t), UK (40 000 t) and Germany (53 000 t). The production data used in the calculations are from Miller (2008b). The gaps in the data, as illustrated by examples of Morocco, Russia and other remind us of semiquantitative aspect of this interpretation. Figure 16 shows the ratios of “reserves”/yearly fluorspar production and “reserve base”/yearly fluorspar production for major fluorspar producing countries. These ratios are crude short term and medium term indicators of in situ fluorspar availability. South Africa has the best potential to remain the major fluorspar producer over the short- and long-term. The ratio of reserves/yearly production for China is lower than for other major fluorspar producing countries. Totalitarian regimes traditionaly overestmated their reserves. Today, the inverse may be true. It is also possible that Chinese mines were high-graded during periods of low fluorspar prices. If the data is correct, assuming that there was no new exploration work going on in China, this country would have less than 8 years of reserves. France, a historical producer, discontinued fluorspar mining in 2006. All other producing countries appear to have enough reserves to last at least 20 years. Their reserve bases could sustain production at their 2007 levels for more than 30 years. Figure 16 is showing that there are over 367 and 600 years of supplies for the category “other” countries. This may potentially provide consumers with a false sense of security if they forget that these countries represented combined production of only 300 000 t of fluorspar in 2007. The last entry in Figure 16, identified as “world” provides a global picture. The ratios world reserves/world yearly production and world reserve base/world yearly production indicate that world reserves and resource base could sustain global world production of 5.31 million t of fluorspar/year for a period of 46 years and 90 years respectively. The geographic shift in fluorspar production from China to the rest of the world is also supported by economic changes. In the past, fluorspar producers in China, benefited from low energy and labour costs and were encouraged to export raw materials. is locatedThe advantages that made China a dominant fluorspar producer are disappearing. A large proportion of the fluorspar reserve base is outside of China (Figure 14), and high fluorspar prices may permit a restart of previously closed fluorspar mines and possibly development of new ones in Africa, North America and Europe. In the short term, China will remain a dominant fluorspar producer and consequently will be influencing fluorspar prices. The relation between supply and demand may not be entirely elastic and shortages in specific fluorspar products may develop. In developed countries it takes several years to bring a new mine into production. Discussion with representatives with current fluorspar producers from Mongolia and Brazil suggest that permitting procedure for a fluorspar mine in these countries take less than a year, therefore any fluorspar shortages are likely to be short-lived. The size of reported reserve base suggests that as long as fluorspar prices remain high, and the market is growing or stable, a number of new development projects could start. How many of these new projects will be successful depend on the future fluorspar market trends. The primary fluorspar projects with high (or at least above average) tonnage and grade, metallurgicaly simple ore, with sound technical financial backing and a strong management team linked to fluorspar consumers, will reach production stage and survive a major economic downturn. Availability of infrastructure and proximity to low transportation cost coridors or proximity to the market are other important section considerations. Selected fluorite occurrences located in British Columbia (Figure 17) are described in the next . Emv K e n n e d y C r e e k Eca Ecb Jkgd Jkgd Rock Candy Creek TERTIARY OR YOUNGER Fluorite Vein Coryell Intrusives Eca Ecb EOCENE Emv JURASSIC - CRETACEOUS Nelson Plutonic Rocks Jkgd Medium grained white syenite Coarse grained pink syenite Andesite, andesite porphyry Granite, granodiorite Geological Contact Roads and Trails METRES 0 250 Dbr Dbr Dbr Dbr Dd Dd Dbr Dd Dd Liard Hotsprings Provincal Park A L S A K A H I G W H A Y 2 km L iar d R e i v r M o u l d M o u l d C r e e k T e e e t er r C e e k GEM SHOWINGS TEE CORAL TAM HENRY FIRE CLIFF NIK CAMP STRAP Dbr Dd BESA RIVER Fm - black shale, calcareous shale, minor dolomite DEVONIAN OR YOUNGER DUNEDIN Fm - limestone, fossiliferous limestone Geological contact / unconformity? Major fluorite occurrences Fluoriter occurrences Devonian Fairholme Group Basel Devonian Unit Camb. - Ord Beaverfoot Formation Skoki Formation McKay Group Fluorite-REE Normal Fault Thrust Fault Float Main (Central) Zone 500 Metres o c n n k e a C r e R k C y o N Fluorite 1 km China France Kenya Mexico Mongolia Namibia Russia S. Africa Spain Other World Years 0 100 200 300 400 500 600 Reserve Base / Production Reserves / Production Morocco USA China France Kenya Mexico Mongolia Spain Namibia South Africa Russia Other Countries World reserve base estimate: 480 million tonnes USA China France (10 million) Kenya Mexico Mongolia Namibia Russia (9 million) South Africa Spain (6 million) Other countries World fluorspar reserve estimate: 240 million tonnes 110 million 41 million 21 million 32 million Fluorspar in British Columbia There are over 78 fluorspar occurrences in British Columbia (Figure 17). Information regarding fluorite is summarized by Pell (1992) and in MINFILE <http://minfile.gov.bc.ca/searchbasic.aspx>. The BC Regional Geochemical Survey <http://webmap.em.gov.bc.ca/Mapplace/ minpot/ex_assist.cfm> provides information regarding fluorine concentrations in water. Such data sets are extremely useful in the early stages of exploration for fluorite and variety of metallic deposits. Rock Candy (fluorite); Eaglet (fluorite ± molybdenum ± celestite [Sr(SO ]); Rexspar (fluorite± celestite), several occurrences in the Laird River district (fluorite ± witherite [BaCO ], barytocalcite and barite) and Rock Canyon Creek (Fluorite ± Rare Earth Element [REE] ± precious metals) are described bellow. 1 m wide) (Figure 17) m F (U) 15 to 120 m thick consisting of related the 4 3 , in SE BC (Figure 17), produced 56,000 t of ore grading 68% CaF and 22% SiO . Over 36,760 t of fluorite and 1,673 t of silica were shipped to Trail smelter. 12,300 t of broken ore may remain in stopes and 47,800 t of probable ore in pillars and sills adjacent to stoped areas. These historic estimates are not NI 43-101 compliant. The deposit consisted of a network of veins which vary from a few cm to 10 m in width and a breccia zone (Figure 5). Mineralization occupies a silicified, north-trending, fracture zone in Tertiary andesitic volcanics adjacent to a large syenite intrusion (Figure 18). Four m wide vein, consisted of massive fluorite was bounded on the west by 1.5 to 2 m of fluorite-matrix breccia and a thin composite banded margin adjacent to altered country rocks. It wa cut by vuggy quartz veins. The marginal breccia contains fragments of country rock in a matrix of fluorite, chalcedony, kaolin, pyrite, quartz and calcite. The banded western margin of the vein consists of barite with calcite, fluorite, chalcedony and quartz. Fluorite veinlets, 4 to 5 cm thick cut the altered host rocks. Historic drilling has shown intermittent fluorite mineralization to the north of the known mineralized zone. Fluorite vein ( is exposed 1 km north of the main workings (Pell, 1992). property is located 3.5 k south from the Birch Island railway station. ive uranium zones and one fluorite deposit (Figure 19) are hosted by a trachyte unit intrusive porphyry and tuff and breccia. The trachyte is underlain by quartz-sericite schist, chlorite schist and dacitic to andesitic volcanic breccia, with interlayers of grey phyllite, slate, chert and sericitic quartzite (Preto, 1978). Shearer (2007) summarizes all available data. U mineralization in BC is considered as a restricted resource (as defined by USGS, 2008). Pre-National Instrument 43-101 resource estimates suggest that 1.4 million t of fluorite mineralization averaging 23.46% CaF (cut-off 15% CaF ) is potentially open pit-mineable (Descarreaux, 1986). If the fluorite mineralization is spatially distinct from U zones, as suggested by past investigations, it may have some development potential. If the fluorite mineralization contains appreciable U or Th concentrations, its the development potential could be affected by strong local opposition to U mining. McCammon (1950) indicates that fluorite-bearing rocks contain anomalous values of Y, La and Ce. Mo and Sr are also reported in anomalous concentrations. Presence of celestite (Sr(SO )) and bastnaesite ((Ca, La, Y)CO F)) may account for some of these. 2 2 2 2 4 3 Rock Candy Mine Rexspar Figure 18: Geology of the Rock Candy Mine. (after Pell, 1992). Figure 15 Geographic location of the fluorspar reserve base (as reported by Miller 2008a). Figure 21. Geological setting of deposits of the Liard fluorite district, northern British Columbia (based on Woodcock, 1972a, from Pell, 1992). Figure 20. Simplified geology of the Eaglet deposit, Central British Columbia (based on Pell, 1992). Figure 19. Geology of the Rexspar Mine (modified from Shearer, 2007). Figure 22. Geology of the Rock Canyon Creek fluorite REE ± precious metal feposit (from Pell, 1992). Liard Eaglet Rexspar Rock Candy Rock Canyon Creek USA Alberta Yukon Pacific Ocean Victoria Vancouver British Columbia Figure 17. Geographic distribution of the fluorite occurrences in British Columbia (black squares). Deposits dicussed in this paper are shown by red ellipses. Summary The nomenclature and regulations used for reporting of ore reserves, resources in many of the developing countries do not follow the same standards as in western countries and are not comparable to those of Canadian National Instrument 43-101. Consequently, legitimate concerns may be raised regarding ore reserve estimates from developing and controlled-market countries. Assuming that world reserve and resource base data compiled by Miller (2008a) is reasonably accurate, there should be no long term in situ shortage of fluorspar . This is a reasonable assumption, unless the balance between supply and demand is affected by new technology requiring fluorite or fluorine, or unexpected conflicts or upheavals impact major fluorspar producing countries. Mexico, South Africa, Mongolia and other countries (including Canada) with known fluorite deposits will step in if reductions in China's fluorspar production persist. New deposits containing ores amenable to production of metallurgical grade fluorspar, which is characterized by larger particle size, are more difficult to find. British Columbiahas an excellent geplogical potential to host world-class fluorite-bearing deposits. Rock Candy, Rexspar, Eaglet, Rock Canyon Creek and the Liard area deposits are examples of florspar resources available in British Columbia. Acid grade concentrate, derived from variety of primary fluorspar deposits or recovered as byproduct of metal mining, accounts for the bulk of the fluorspar market. Environmental pressures on the fertilizer industry will moderate long term growth in fluorspar demand through increased recovery of F from phosphate rocks may to some extent reduce needs for acid grade fluorspar concentrate. EARLY MISSISSIPIAN Quesnel Lake Gneiss LATE PROTEROZOIC Snowshoe Group Granitic Orthogneissis Hybride Contact Zone Metasedimentary Rock Geological Contact Adit 1, 2 Significant Fluorspar Mineralization Quesnel Lake Barrett Creek Wasco L. W ascoCr ek 500 Metres 1 2 N Liard Rock Canyon Creek district (Figure 17) extends for 17 km north from Liard Hot Springs Provincial Park (Figure 21). More than 20 fluorite occurrences are located along an irregular, breciated, probably unconformable contact (Woodcock, l972a) separating the Upper Devonian Besa River Formation (shale) from the Middle Devonian Dunedin Formation (limestone). Fluorite occurs as lens-shaped or irregular replacement bodies, veins and as cement in breccias. Most of occurrences are described by Woodcock and Smitheringale (1955); Woodcock (1972a), McCammon (1973) and Pell (1992). Results of metallurgical tests are provided in Woodcock (1972b). The Gem, Tam, Coral-Camp and Tee deposits are the main deposits. Tam and Coral-Camp are described bellow. mineralization forms replacements and breccia cements in limestone and shale. Fluorite is accompanied by witherite (BaCO , barytocalcite ((Ba,Ca)CO ) and barite (BaSO ). Indicated and potential historical resource (not National Instrument 43-101 compliant)nof 500,000 t averaging 36.7% CaF are reported by Mineral Policy Sector (Corporation Files:) suggest that follow-up may be justified. area consists of limestone breccia, cemented and/or replaced by fluorite, witherite, minor barite and barytocalcite. At the main showings, diamond drilling intersected 26.5 m of 39 CaF (Woodcock, 1972a). Several 3-metre long channel samples assayed up to 88 fluorite and a bulk sample assayed at 64.88 CaF (Woodcock, 1972b; McCammon, 1973). deposit, is located 50 km east of Canal Flats, (Figure 17). The deposit is interpreted as a stratabound, 3.5 km long belt of fluorspar/rare-earth mineralization, exposed in five mineralized zones and hosted mainly by dolomite and limestone ("basal Devonian unit" on Figure 22). The main type of fluorite mineralization consists of disseminations and veinlets of dark purple fluorite in a carbonate matrix (Figure 6). Ce, La and Nd are present in anomalous concentrations (Hora and Kwong, 1986). Bastnaesite, pyrite, gorceixite, calcite, limonite, illite, barite, parisite, apatite were reported as minor constituents by Pell (1992) and Hora and Kwong (1986). Follow up studies did not confirm gorceixite and bastanaesite but suggest that synchysite and goyazite are present (Graf, undated; Sampson et. al., 2003). Fluorite content varies from 2 to more than 10% of the rock but most high grades came from samples that were not found in situ (Pell (1992). One sample from vein-type mineralization assayed 201 gr/t Ag and 0.8 g/t Au (Graf, undated). Subsequent electron microprobe studies suggest that Ag occurs in the form of tellurides (Graf, undated). Based on the coexistence of fluorite with REE mineralization, this deposit was interpreted as carbonatite- or a deep-seated alkaline intrusion- related deposit (Pell and Hora (1987). Most of the trenches are collapsed and heavily overgrown. The owner of the property is convinced that the next stage of the exploration should consist of drilling and sampling of the main zone as potential source of REE and fluorite. Tam The Coral-Camp % % 3) 3 4 2 2 % 2 magnetite and pyrochlore present as accessory minerals (Hora et al., 2008). Historical fluorite resource, pre-dating NI 43-101, is reported to be 24 million t grading 11.5% CaF (Eaglet Mines Ltd. Annual Report 1984). According to Hora (2005), who reports on results of recent chemical analyses of drill core obtained during the 1980 to 1984 exploration programs, Mo is reported in a large number of samples, but independent of F, Sr, Pb, Cu and Zn concentrations. He also indicates that about 25% of Mo values are in the 0.001 - 0.02% range and that the dark purple fluorite is enriched in the Th and light REE relative to the green and colorless varieties. Recent press release put emphasis on Mo mineralization (Freeport, 2008) and appears in line with the internal Eaglet Mines Ltd. document from the early 1980's quoted by Hora (2008). The later indicates that fluorspar and saleable MoS concentrates were obtained in pilot tests by Kamloops Research and Assay Laboratory Ltd. 2 2 Eaglet deposit (Figure 17), is located on the shore of Quesnel Lake. Mineralization occurs in an area of 1500 by 900 m, but little of it outcrops (Pell, 1992). Fluorite is hosted by quartz- feldspar-mica gneiss injected by pegmatite, aplite and granitic rocks. Chloritic, sericitic and potassic alteration with associated biotite and epidote is common in the mineralized area (Pell, 1992). The geology is summarized on Figure 20. Fluorite is disseminated in the country rock and in fracture fillings (from hairline to over 15 cm in width), or as masses 15 to 20 cm across. Galena, sphalerite, molybdenite, celestite, and pyrite are reported within fluorite-bearing area. Gangue minerals consist of feldspar, quartz, calcite, siderite, gypsum, dickite and allanite (Pell, 1992; Hora et al. 2008) with rutile, zircon, sphene, fluorapatite, Acknowledgements Appreciation is extended to Mr. Hector Valle Martin, the Director General / C.E.O of MEXICHEM in Mexico, Mr. Denis Cook of the Vergenoeg Mining Company (PTY) Ltd. in South Africa for the permission to use their photographs. The author was assisted in the field by Alan Duffy, a graduate from the Trinity College, Ireland. Field collaboration with Chris Graff of the Spectrum Mining Co. and Bob Jackson owner of the Rock Candy Mine was greatly appreciated. 1 2 British Columbia Ministry of Energy Mines and Petroleum Resources, Victoria, BC, Canada. School of Earth and Ocean Sciences, University of Victoria, BC, Canada N References: For more information or for references cited in this document please contact: [email protected]; or [email protected]
Transcript of Fluorspar POSTER ROUNDUP 09 ...
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FLUORSPAR MARKET REVIEW AND SELECTED FLUORITE DEPOSITSIN BRITISH COLUMBIA, CANADA
George J. Simandl1,2
Suggested reference style:Simandl G.J.(2009): Fluorspar market and selectedfluorite-bearing deposits, British Columbia, Canada.
Geofile 2009-03. Poster.British Columbia Ministry of Energy and Mines;
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IntroductionFluorspar is the commercial term for fluorite (CaF ) Fluorite contains 51.1% Ca and 48.9% F. Collector specimens occur as cubes and octahedrons. Typicalfluorspar ores are massive , disseminations, or form layered crusts, globular and botroidal aggregates and cox-comb textures. Other sources of F are cryoliteand phosphate rock. Cryolite (Na AlF ) was historicallymined in Greenland. Due to environmental pressure, F compounds are now recovered during theprocessing of sedimentary phosphates. Fluosilic acid (H SiF ) is one of these compounds. environmental regulations suggestthat this acid will be increasingly converted into Al- or Ca-fluorides, cryolite, or H. Phosphate rock reserves in the USA alone contain 370 million tonnes of F.
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3 6
2 6 , used in water fluoridation, Strict
Fluorspar is used largely in the manufacturing of fluorocarbons for refrigerants, foam products, polytetrafluoroethylene (“Teflon”) and other fluoropolymers.Petroleum alkylation, glass, medical, agricultural and metallurgical uses also represent important markets. Demand for fluorspar in the manufacture offluoropolymers and fluoroelastomers, including partially fluorinated polymers or copolymers is growing. Over 70% of fluorspar used in developed countries istransformed into HF products, while in developing countries over 65% of fluorite is used in steel-making. Fluorspar uses in USA are summarized onAluminum fluoride (AlF ) and synthetic cryolite, derived largely from acid grade fluorspar, are the main F compounds used in aluminum (Al) smelting. Thegrowth of this market is favoured by increasing demand for Al in the automotive industry, but it is counterbalanced by improvements in smelting technology,increased recycling of both, Al and F, and by increased use of AlF derived from fluosilic acid. Fluorspar products are sold to steel mills, cement plants,foundries, glass and ceramic plants, and welding rod manufacturers where they are used as fluxes.
3
3
Figure 1.
Fluorspar Production and PricesFluorspar production first exceeded 1 million t/year during World War II It peaked at 5.56 million t/year in 1989 and then bottomed out at 3.75million t/year in 1994 due to restrictions on the use of fluorocarbons (particularly CFCs) related to the Montreal Protocol.. The market stabilized in the 4.2 -4.5 million t/year range between 1997 and 2000. By 2004 fluorspar production consistently exceeded 5 million t/year (US Geological Survey, 2007). Thevariation in price of fluorspar in the USA over the last 100 years is shown on
(Figure 1).
Figure 2.
Figure 1. Fluorspar uses in USA. Data from Miller (2008b).
Major Fluorspar-producing CountriesIn 2007 world fluorspar production was 5.59 million t ( . China, at 3.2 million t, is the largest fluorspar producing country ( and stronglyinfluence fluorspar prices. It is followed by Mexico (933 000 t), Mongolia (380 000 t), South Africa (285 000 t), Russia (180 000 t), Spain (155 500 t), Namibia(118 000 t) and Morocco (95 000 t). Recently, China has been diverting an increased proportion of its fluorspar output to domestic production of HF and thusits fluorspar exports shrinked. Prices of fluorspar concentrates have risen in terms of US dollars (Figure 2), creating opportunities for fluorspar producersoutside of China. Since the summer of 2007, economic growth in China slowed down and it remains to be seen if China will maintain its export restrictions..
Miller, 2008b)s
Figure 4)
Figure 4. World metallurgical and acid grade fluorspar production by country for the year2007. Data from Miller (2008b).
0
500
1000
1500
2000
2500
3000
3500
Bra
zil
Ch
ina
10
00
me
tric
ton
ne
s
Ind
ia
Ke
nya
Me
xic
o
Mo
ng
olia
Mo
rocco
N.
Ko
rea
Na
mib
ia
Pa
kis
tan
Ru
ssia
S.A
fric
a
Th
aila
nd
Tu
rke
y
UK
Oth
er
Sp
ain
Ta
jikis
tan
Acid grade
Metallurgical & acid grades
Metallurgical grade
Ge
rma
ny
Figure 7: Fluorite disseminated in trachytic meta-tuff, Rexspar deposit, centralBritish Columbia, Canada. Fluorite is purple to almost black. Weatheredsulphides give rock rusty-brown appearance (fine division on the scale = 1mm).
Figure 6: Crackle breccia. Dark purple, fine-grained fluorite fills fractures andreplaces pale gray limestone. Rock Canyon Creek deposit, southeastern BritishColumbia, Canada.
Figure 5: Coarse fluorite (pale to dark green) cementing a breccia andreplacing fragments of the host rock. Rock Candy mine, southern BritishColumbia, Canada.
Figure 8: Fluorite vein grade model can be used in mineral potentialevaluations and in early screening of fluorite development projects. FromOrris (1992).
Figure 9: : Fluorite vein tonnage model can be used in mineralpotential evaluations and in early screening of fluorite developmentprojects. From Orris (1992).
Figure 10: Underground Fluorspar Minelocated near Potosi, Mexico; photo usedwith permission of MEXICHEM.
Figure 11: Large open pit fluorite mine, within the giant Vergenoeng fluorite - iron oxide - fayalitepipe, South Africa. White pick-up truck for scale. Photo used with permission of VergenoegMining Company Ltd.
23 44 64
0 10 20 30 40 50 60 70 80 90 100
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
N=25
Fluorite grade (% CaF )2
Pro
po
rtio
no
fd
ep
osits
0.04 0.68 11
0.0016 0.0063 0.025 0.1 0.4 1.6 6.3 25 100 400 1600
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
N=25
Million tonnes (CaF )2
Pro
port
ion
ofdeposits
Figure 12: Acid grade fluorspar concentrate; particles are less than 1mm in size. Photo used with the permission of the MEXICHEM.
Figure 13: Metallurgical grade fluorspar concentrate. The ruler is in inches andcentimeters for scale. Photo used with the permission of the MEXICHEM
Figure 14 Geographic location of known fluorsparreserves (data reported by Miller 2008a).
Figure 16 Ratios of “reserves” and “reserve base” to the 2007 yearlyproduction can be used as crude relative indicators of fluorsparavailability. The ratio involving reserves looks at near term availability andratio involving reserve base provide longer term estimate. The accuracyand precision of these estimates are ultimately dependent on the qualityof the database (in this case we use the reserves and reserve base datafrom Miller (2008a) and yearly productions as reported by Miller (2008b)).
Figure 2. World Fluorspar production
Figure 3. Fluorspar prices in USA.
Fluorspar GeologyMontroc Le Moulinal
Fluorite occurs in variety of geological settings. It is the only (or the main) ore mineral in classical deposits: such as: Las Cuevas, Encantada-Buenavista, ElTriangulo, (Mexico); St. Lawrence pluton-related veins and the Rock Candy Mine (Canada); El Hamman veins (Morocco) and Le Burc,and Trebas deposits (France). Fluorite also occurs in association with other industrial minerals or metals in carbonatites and alkaline complexes, MississippiValley type Pb-Zn-fluorite-barite deposits, fluorite-barite-(Pb-Zn) veins, hydrothermal Fe (± Au, ±Cu) and REE deposits, precious metal concentrations,fluorite/metal-bearing skarns, Sn-polymetallic greissen-type deposits, zeolitic rocks and uranium deposits. At first glance the co-production of fluorite withmetals appears an attractive proposition but in most cases such association represents increased capital and processing costs. From the engineer's point of view,economic fluorite deposits occur as simple or composite veins, stockworks and breccia zones , diatreme pipes, disseminations orother features where fluorite occurs as open space fillings (such as in karst). Replacement-type, residual (unconformity-related) and stratiform bodies are alsoknown to form high-grade deposits. Vein-type deposits have historically supplied the majority of the fluorspar market. Grade and tonnage curves (Figures 8and 9 ) cover vein-type deposits. These curves were originally produced for mineral potential assessments, but they can be used during the early screening ofexploration projects. The vertical axis of these diagrams extends from zero to one. The horizontal axis represents either tonnage or grade (% CaF ). Forexample, from Figure 8 we can determine that 90% (0.9 on the vertical scale) of fluorite vein-type deposits have grades ( CaF . content) higher than 23%. Half(0.5 on the vertical scale) of these deposits grade higher than 44% CaF . Less than 10% (0.1 on the vertical scale) of the deposits have a grade higher than 64 %CaF . The same approach is used to interpret the High grade, large tonnage deposits are preferred targets. The shape, orientation, depth ofmineralization and geotechnical parameters determin if fluorspar is extracted by surface or underground mining (Figure 10 and 11). For large, medium to lowgrade ore deposits containing minerals with similar properties to fluorspar, the processing circuit are complex. Heavy-media separation, followed by differentialflotation , combined with other methods are common practice. Fine-grain flotation concentrates (or dust) may be pelletized or briquetted to satisfy consumerneeds. Deposits, able to provide coarse and high-grade fluorite-rich ores (or usable concentrate requiring simple metallurgical processing) are primaryexploration targets, but other large tonnage, lower grade deposits are being investigated. The presence of metallic minerals within fluorite ore may improve orimpair the economic viability of a deposit. If metallurgical and economic parameters are satisfied, fluorspar is recovered as by-product of metal mining (e.g.Pb-Zn veins, Mississippi Valley type Pb-Zn deposits,, barite-fluorite, REE-fluorite and uranium-fluorite deposits), where fluorite accounts for 10% or more ofthe ore. Fluorite is also recovered from tailings associated with historic mines in Mexico and Europe.
2
2
2,
2
(Figures 5 and 6) (Figure 7)
Figure 9.
Fluorite Ores and Grades of ConcentrateThe texture, mineralogy and chemistry of the mine-run are reflected in the silica, sulphur, calcite and minor and trace element content of fluorite concentrates, affectingthe marketability of products.Concentratess are subdivided into ceramic, metallurgical and acid grades (Harben, 1999; British Geological Survey, 2005).
is commonly fine-grained and subdivided to No.1 product - 95-96% CaF , < 3% SiO <0.12 ferric oxides, low calcite content and traces of Pb and Znand No.2 product contains 85% to > 90% CaF
concentrate must contain more than 97% CaF , < 1.5% SiO , 0.03 0.10% S (as sulphide or free S), <12 ppm As, 100 - 550 ppm P, plus low concentrationsof Pb, Cd, Be, CaCO and moisture (Harben, 1999). This grade is produced by the flotation process so its particle size is typically 100 mesh or lower
concentrate must contain > 80% CaF < 15% SiO , and the material must pass through a 1.0 to 1.5 inch screen while less than 15% of that materialshould pass through a 1/16th inch screen (Harben, 1999). In the USA, metallurgical grade fluorspar needs to have over 60 effective % fluorspar ({%CaF - [2.5 x%SiO ] } > 60). Fines meeting or slightly exceeding chemical specifications of metallurgical grade products may be pelletized or briquetted and used as a substitute forthe traditional “gravel-type” fluorspar products seen in several segments of the metallurgical industry (Figure 13).While acid grade concentrate is considered by users as the highest quality product (> 97% CaF ), it is commonly produced from lower grade ore than metallurgical gradeconcentrate. This is possible because acid-grade concentrate does not have to be coarse-grained (fine-grinding and flotation can be used for upgrading). To producemetallurgical grade (“gravel-type”) rather exceptional deposit is required, or the ore must be extracted by selectivemining To preserve coarse fluorite particles, the minerun is only crushed, sorted (sometimes by hand or upgraded using a heavy media separation circuit), screened, dedusted and dried before packing and shipping.
2 2,
2.
2 2
3
2, 2
2
2
2
, ..
Ceramic grade
Acid grade
Metallurgical grade(Figure 12).
Fluorspar AvailabilityThe availability of fluorspar , based on a compilation of Miller (2008a) is summarized in Figures 14 and 15. Data probably incorporate a large margin of error (it is highly unlikelythat world “reserves” are exactly 50% of the world “reserve base”). US Geological Survey (2008) definitions of the terms “resources”, “reserves” and “reserve base” are definedbelow. The term “resource” refers to “a concentration of naturally occurring solid, liquid, or gaseous material in or on the Earth's crust in such form and amount that economicextraction of a commodity from the concentration is currently or potentially feasible”.The term “reserve base” refers to “an identified resource that meets specified minimum physical and chemical criteria related to current mining and production practices, includingthose for grade, quality, thickness, and depth. The reserve base is the in place demonstrated (measured plus indicated) resource from which reserves are estimated. It mayencompass those parts of the resources that have a reasonable potential for becoming economically available within planning horizons beyond those that assume proventechnology and current economics. The reserve base includes those resources that are currently economic (reserves), marginally economic (marginal reserves), and some of thosethat are currently sub-economic (subeconomic resources)”.“Reserves” are “a part of the reserve base which could be economically extracted or produced at the time of determination. The term reserves need not signify that extractionfacilities are in place and operative. Reserves include only recoverable materials”. South Africa stands out because its reserves and reserve base could sustain the 2007-levelproduction (295 000 t/year) for 139 and 275 years respectively. Morocco is a major producer, yet Miller (2008a) does not have information regarding its fluorspar reserves orreserve base. Russia’s reserves are described as “moderate”. In the absence of better data we have extrapolated Russia's reserves to be half the size of its reserve base. Some otherfluorspar producing countries listed by Miller (2008b), not shown on Figure 16 for similar reasons, are Brazil (63 700 t), Iran (65 000 t), UK (40 000 t) and Germany (53 000 t).The production data used in the calculations are from Miller (2008b). The gaps in the data, as illustrated by examples of Morocco, Russia and other remind us of semiquantitativeaspect of this interpretation. Figure 16 shows the ratios of “reserves”/yearly fluorspar production and “reserve base”/yearly fluorspar production for major fluorspar producingcountries. These ratios are crude short term and medium term indicators of in situ fluorspar availability. South Africa has the best potential to remain the major fluorsparproducer over the short- and long-term. The ratio of reserves/yearly production for China is lower than for other major fluorspar producing countries. Totalitarian regimestraditionaly overestmated their reserves. Today, the inverse may be true. It is also possible that Chinese mines were high-graded during periods of low fluorspar prices. If the data iscorrect, assuming that there was no new exploration work going on in China, this country would have less than 8 years of reserves. France, a historical producer, discontinuedfluorspar mining in 2006. All other producing countries appear to have enough reserves to last at least 20 years. Their reserve bases could sustain production at their 2007 levelsfor more than 30 years. Figure 16 is showing that there are over 367 and 600 years of supplies for the category “other” countries. This may potentially provide consumers with afalse sense of security if they forget that these countries represented combined production of only 300 000 t of fluorspar in 2007. The last entry in Figure 16, identified as“world” provides a global picture. The ratios world reserves/world yearly production and world reserve base/world yearly production indicate that world reserves and resourcebase could sustain global world production of 5.31 million t of fluorspar/year for a period of 46 years and 90 years respectively. The geographic shift in fluorspar production fromChina to the rest of the world is also supported by economic changes. In the past, fluorspar producers in China, benefited from low energy and labour costs and were encouragedto export raw materials. is locatedThe advantages that made China a dominant fluorspar producer are disappearing. A large proportion of the fluorspar reserve base is outside ofChina (Figure 14), and high fluorspar prices may permit a restart of previously closed fluorspar mines and possibly development of new ones in Africa, North America andEurope. In the short term, China will remain a dominant fluorspar producer and consequently will be influencing fluorspar prices. The relation between supply and demand maynot be entirely elastic and shortages in specific fluorspar products may develop. In developed countries it takes several years to bring a new mine into production. Discussion withrepresentatives with current fluorspar producers from Mongolia and Brazil suggest that permitting procedure for a fluorspar mine in these countries take less than a year,therefore any fluorspar shortages are likely to be short-lived. The size of reported reserve base suggests that as long as fluorspar prices remain high, and the market is growing orstable, a number of new development projects could start. How many of these new projects will be successful depend on the future fluorspar market trends. The primaryfluorspar projects with high (or at least above average) tonnage and grade, metallurgicaly simple ore, with sound technical financial backing and a strong management team linkedto fluorspar consumers, will reach production stage and survive a major economic downturn. Availability of infrastructure and proximity to low transportation cost coridors or
proximity to the market are other important
section
considerations. Selected fluorite occurrences located in British Columbia (Figure 17) are described in the next.
Emv
Kennedy Creek
Eca
Ecb
Jkgd Jkgd
Rock CandyCreek
TERTIARY OR YOUNGER
Fluorite Vein
Coryell Intrusives
Eca
Ecb
EOCENE
Emv
JURASSIC - CRETACEOUS
Nelson Plutonic Rocks
Jkgd
Medium grained white syenite
Coarse grained pink syenite
Andesite, andesite porphyry
Granite, granodiorite
Geological Contact
Roads and Trails
METRES
0 250
Dbr
Dbr
Dbr
Dbr
Dd
Dd
Dbr
Dd
Dd
Liard Hotsprings
Provincal
Park
A L SA K A H I GWH
A Y
2 kmLia
r
d Rei v r
Mo
u
ld
Mo
u
ld
Cr
ee
k
Te
e
e
t er
r
C
e
e k
GEM SHOWINGS
TEE
CORAL
TAM
HENRY
FIRE
CLIFF
NIK CAMP
STRAP
Dbr
Dd
BESA RIVER Fm - black shale,calcareous shale, minor dolomite
DEVONIAN OR YOUNGER
DUNEDIN Fm - limestone,fossiliferous limestone
Geological contact / unconformity?
Major fluorite occurrences
Fluoriter occurrences
Devonian
Fairholme Group
Basel Devonian Unit
Camb. - Ord
Beaverfoot Formation
Skoki Formation
McKay Group
Fluorite-REE
Normal Fault
Thrust Fault
Float
Main (Central)Zone
500 Metres
ocn
n
k
e
aCre
R
k
Cyo
N
Fluorite
1 km
Ch
ina
Fra
nce
Ke
nya
Me
xic
o
Mo
ng
olia
Na
mib
ia
Ru
ssia
S.A
fric
a
Sp
ain
Oth
er
World
Ye
ars
0
100
200
300
400
500
600
Reserve Base / Production
Reserves / Production
Mo
rocco
USA
China
France
Kenya
Mexico
MongoliaSpain
NamibiaSouth Africa
Russia
Other Countries
World reserve base estimate: 480 million tonnes
USA China France (10 million)
Kenya
Mexico
Mongolia
NamibiaRussia (9 million)
South Africa
Spain (6 million)
Othercountries
World fluorspar reserve estimate: 240 million tonnes
110 million
41 million
21 million
32 million
Fluorspar in British ColumbiaThere are over 78 fluorspar occurrences in British Columbia (Figure 17). Information regarding fluorite is summarized by Pell (1992) and inMINFILE <http://minfile.gov.bc.ca/searchbasic.aspx>. The BC Regional Geochemical Survey <http://webmap.em.gov.bc.ca/Mapplace/minpot/ex_assist.cfm> provides information regarding fluorine concentrations in water. Such data sets are extremely useful in the earlystages of exploration for fluorite and variety of metallic deposits. Rock Candy (fluorite); Eaglet (fluorite ± molybdenum ± celestite[Sr(SO ]); Rexspar (fluorite± celestite), several occurrences in the Laird River district (fluorite ± witherite [BaCO ], barytocalcite and barite)and Rock Canyon Creek (Fluorite ± Rare Earth Element [REE] ± precious metals) are described bellow.
1 m wide)
(Figure 17) m F (U)15 to 120 m thick consisting of related
the
4 3
, in SE BC (Figure 17), produced 56,000 t of ore grading 68% CaF and 22% SiO . Over 36,760 t of fluorite and1,673 t of silica were shipped to Trail smelter. 12,300 t of broken ore may remain in stopes and 47,800 t of probable ore in pillars and sillsadjacent to stoped areas. These historic estimates are not NI 43-101 compliant.The deposit consisted of a network of veins which varyfrom a few cm to 10 m in width and a breccia zone (Figure 5). Mineralization occupies a silicified, north-trending, fracture zone in Tertiaryandesitic volcanics adjacent to a large syenite intrusion (Figure 18). Four m wide vein, consisted of massive fluorite was bounded on thewest by 1.5 to 2 m of fluorite-matrix breccia and a thin composite banded margin adjacent to altered country rocks. It wa cut by vuggyquartz veins. The marginal breccia contains fragments of country rock in a matrix of fluorite, chalcedony, kaolin, pyrite, quartz and calcite.The banded western margin of the vein consists of barite with calcite, fluorite, chalcedony and quartz. Fluorite veinlets, 4 to 5 cm thick cutthe altered host rocks. Historic drilling has shown intermittent fluorite mineralization to the north of the known mineralized zone. Fluoritevein ( is exposed 1 km north of the main workings (Pell, 1992).
property is located 3.5 k south from the Birch Island railway station. ive uranium zones and one fluoritedeposit (Figure 19) are hosted by a trachyte unit intrusive porphyry and tuff and breccia. Thetrachyte is underlain by quartz-sericite schist, chlorite schist and dacitic to andesitic volcanic breccia, with interlayers of grey phyllite, slate,chert and sericitic quartzite (Preto, 1978). Shearer (2007) summarizes all available data. U mineralization in BC is considered as arestricted resource (as defined by USGS, 2008). Pre-National Instrument 43-101 resource estimates suggest that 1.4 million t of fluoritemineralization averaging 23.46% CaF (cut-off 15% CaF ) is potentially open pit-mineable (Descarreaux, 1986). If the fluoritemineralization is spatially distinct from U zones, as suggested by past investigations, it may have some development potential. If the fluoritemineralization contains appreciable U or Th concentrations, its the development potential could be affected by strong local opposition to Umining. McCammon (1950) indicates that fluorite-bearing rocks contain anomalous values of Y, La and Ce. Mo and Sr are also reported inanomalous concentrations. Presence of celestite (Sr(SO )) and bastnaesite ((Ca, La, Y)CO F)) may account for some of these.
2 2
2 2
4 3
Rock Candy Mine
Rexspar
Figure 18: Geology of the RockCandy Mine. (after Pell, 1992).
Figure 15 Geographic location of the fluorspar reserve base(as reported by Miller 2008a).
Figure 21. Geological setting ofdeposits of the Liard fluorite district,northern British Columbia (based onWoodcock, 1972a, from Pell, 1992).
Figure 20. Simplified geology of the Eaglet deposit, Central British Columbia (based onPell, 1992).
Figure 19. Geology of the Rexspar Mine (modified from Shearer, 2007).
Figure 22. Geology of the Rock Canyon Creek fluorite REE ± preciousmetal feposit (from Pell, 1992).
Liard
Eaglet
Rexspar
Rock Candy
RockCanyonCreek
USA
Alberta
Yukon
Pacific
Ocean
VictoriaVancouver
British
Columbia
Figure 17. Geographic distribution of the fluorite occurrences in BritishColumbia (black squares). Deposits dicussed in this paper are shown byred ellipses.
SummaryThe nomenclature and regulations used for reporting of ore reserves, resources in many of the developing countries do not follow the same standards as in westerncountries and are not comparable to those of Canadian National Instrument 43-101. Consequently, legitimate concerns may be raised regarding ore reserveestimates from developing and controlled-market countries.Assuming that world reserve and resource base data compiled by Miller (2008a) is reasonably accurate, there should be no long term in situ shortage of fluorspar .This is a reasonable assumption, unless the balance between supply and demand is affected by new technology requiring fluorite or fluorine, or unexpected conflictsor upheavals impact major fluorspar producing countries. Mexico, South Africa, Mongolia and other countries (including Canada) with known fluorite deposits willstep in if reductions in China's fluorspar production persist.
New deposits containing ores amenable to production of metallurgical grade fluorspar, which is characterized by larger particle size, are more difficult to find.British Columbia has an excellent geplogical potential to host world-class fluorite-bearing deposits. Rock Candy, Rexspar, Eaglet, Rock Canyon Creek and the Liardarea deposits are examples of florspar resources available in British Columbia.
Acid grade concentrate, derived from variety of primary fluorspar deposits or recovered as byproductof metal mining, accounts for the bulk of the fluorspar market. Environmental pressures on the fertilizer industry will moderate long term growth in fluorspardemand through increased recovery of F from phosphate rocks may to some extent reduce needs for acid grade fluorspar concentrate.
EARLY MISSISSIPIANQuesnel Lake Gneiss
LATE PROTEROZOICSnowshoe Group
Granitic Orthogneissis
Hybride Contact Zone
Metasedimentary Rock
Geological Contact
Adit 1, 2
Significant FluorsparMineralization
QuesnelLake
Barrett Creek
Wasco L.WascoCreek
500 Metres
1
2
N
Liard
Rock Canyon Creek
district (Figure 17) extends for 17 km north from Liard Hot Springs Provincial Park (Figure 21). More than 20 fluorite occurrencesare located along an irregular, breciated, probably unconformable contact (Woodcock, l972a) separating the Upper Devonian Besa RiverFormation (shale) from the Middle Devonian Dunedin Formation (limestone). Fluorite occurs as lens-shaped or irregular replacementbodies, veins and as cement in breccias. Most of occurrences are described by Woodcock and Smitheringale (1955); Woodcock (1972a),McCammon (1973) and Pell (1992). Results of metallurgical tests are provided in Woodcock (1972b). The Gem, Tam, Coral-Camp and Teedeposits are the main deposits. Tam and Coral-Camp are described bellow. mineralization forms replacements and breccia cements inlimestone and shale. Fluorite is accompanied by witherite (BaCO , barytocalcite ((Ba,Ca)CO ) and barite (BaSO ). Indicated and potentialhistorical resource (not National Instrument 43-101 compliant)nof 500,000 t averaging 36.7% CaF are reported by Mineral Policy Sector(Corporation Files:) suggest that follow-up may be justified. area consists of limestone breccia, cemented and/orreplaced by fluorite, witherite, minor barite and barytocalcite. At the main showings, diamond drilling intersected 26.5 m of 39 CaF(Woodcock, 1972a). Several 3-metre long channel samples assayed up to 88 fluorite and a bulk sample assayed at 64.88 CaF (Woodcock,1972b; McCammon, 1973).
deposit, is located 50 km east of Canal Flats, (Figure 17). The deposit is interpreted as a stratabound, 3.5 kmlong belt of fluorspar/rare-earth mineralization, exposed in five mineralized zones and hosted mainly by dolomite and limestone ("basalDevonian unit" on Figure 22). The main type of fluorite mineralization consists of disseminations and veinlets of dark purple fluorite in acarbonate matrix (Figure 6). Ce, La and Nd are present in anomalous concentrations (Hora and Kwong, 1986). Bastnaesite, pyrite, gorceixite,calcite, limonite, illite, barite, parisite, apatite were reported as minor constituents by Pell (1992) and Hora and Kwong (1986). Follow upstudies did not confirm gorceixite and bastanaesite but suggest that synchysite and goyazite are present (Graf, undated; Sampson et. al.,2003). Fluorite content varies from 2 to more than 10% of the rock but most high grades came from samples that were not found in situ(Pell (1992). One sample from vein-type mineralization assayed 201 gr/t Ag and 0.8 g/t Au (Graf, undated). Subsequent electronmicroprobe studies suggest that Ag occurs in the form of tellurides (Graf, undated). Based on the coexistence of fluorite with REEmineralization, this deposit was interpreted as carbonatite- or a deep-seated alkaline intrusion- related deposit (Pell and Hora (1987). Mostof the trenches are collapsed and heavily overgrown. The owner of the property is convinced that the next stage of the exploration shouldconsist of drilling and sampling of the main zone as potential source of REE and fluorite.
Tam
The Coral-Camp%
%
3) 3 4
2
2
% 2
magnetite and pyrochlore present as accessory minerals (Hora et al., 2008). Historical fluorite resource, pre-dating NI 43-101, is reportedto be 24 million t grading 11.5% CaF (Eaglet Mines Ltd. AnnualReport 1984).According to Hora (2005), who reports on results of recent chemical analyses of drill core obtained during the 1980 to
1984 exploration programs, Mo is reported in a large number of samples, but independent of F, Sr, Pb, Cu and Zn concentrations. Healso indicates that about 25% of Mo values are in the 0.001 - 0.02% range and that the dark purple fluorite is enriched in the Th and lightREE relative to the green and colorless varieties. Recent press release put emphasis on Mo mineralization (Freeport, 2008) and appears inline with the internal Eaglet Mines Ltd. document from the early 1980's quoted by Hora (2008). The later indicates that fluorspar andsaleable MoS concentrates were obtained in pilot tests by Kamloops Research and Assay Laboratory Ltd.
2
2
Eaglet deposit (Figure 17), is located onthe shore of Quesnel Lake.Mineralization occurs in an area of 1500by 900 m, but little of it outcrops (Pell,1992). Fluorite is hosted by quartz-feldspar-mica gneiss injected bypegmatite, aplite and granitic rocks.Chloritic, sericitic and potassic alterationwith associated biotite and epidote iscommon in the mineralized area (Pell,1992). The geology is summarized onFigure 20. Fluorite is disseminated in thecountry rock and in fracture fillings (fromhairline to over 15 cm in width), or asmasses 15 to 20 cm across. Galena,sphalerite, molybdenite, celestite, andpyrite are reported within fluorite-bearingarea. Gangue minerals consist of feldspar,quartz, calcite, siderite, gypsum, dickiteand allanite (Pell, 1992; Hora et al. 2008)with rutile, zircon, sphene, fluorapatite,
AcknowledgementsAppreciation is extended to Mr. Hector Valle Martin, the Director General / C.E.O of MEXICHEM in Mexico, Mr. Denis Cook of the Vergenoeg Mining Company(PTY) Ltd. in South Africa for the permission to use their photographs. The author was assisted in the field by Alan Duffy, a graduate from the Trinity College,Ireland. Field collaboration with Chris Graff of the Spectrum Mining Co. and Bob Jackson owner of the Rock Candy Mine was greatly appreciated.
1 2British Columbia Ministry of Energy Mines and Petroleum Resources, Victoria, BC, Canada. School of Earth and Ocean Sciences, University of Victoria, BC, Canada
N
References:For more information or for references cited in this document please contact: [email protected]; or [email protected]
