Colosseum Mine

San Bernardino County, California, United States

GoldSilverCopperLeadArsenicAntimonyZinc

⌖ Show on map USGS source ↗

Commodities

PrimaryGold, Silver

SecondaryCopper

TertiaryLead, Arsenic, Antimony, Zinc

Commodity typeM

Deposit

Deposit typeHydrothermal breccia-filling (hydrothermal pipe)

Deposit sizeL

Orebody formPipe

Ore controlEconomic gold mineralization occurs within two felsite (rhyolite) breccia pipes. Gold occurs as fine, rounded inclusions inside of coarse, euhedral pyrite or in contact with pyrite as fracture fillings or along grain boundaries (Corbett, 1980, cited in Sharp, 1984, pg. 138). The more numerous occurrences are as fillings and boundary coatings. The gold was further determined to be alloyed with silver and of a size range of 1 to 30 microns with the majority from 5 to 20 microns.\n\nAs reported by Davis and others (1989), gold at the Colosseum Mine is generally submicroscopic and associated with sulfide mineralization, chiefly pyrite. It occurs as free gold, with minor alloyed silver. It is primarily in contact with pyrite in fractures in the pyrite or along pyrite grain edges. Secondarily, it occurs as isolated particles in quartz and other gangue minerals but spatially always close to pyrite, and rarely as particles encased in euhedral pyrite.\n\nThe pyrite mineralization and minor base metal sulfides occur in three distinct styles: (1) as disseminations, (2) as open space filling or vein/fracture filling, and (3) in breccia clasts replacing dolomite. The pyrite megascopically ranges from absent to 30% of rock volume within the breccia pipes (Davis and others, 1989).\n\nAlthough the gold is apparently spatially and geochemically associated with pyrite, there is only a general proportional relationship between pyrite content and gold content. Sometimes, a high volume percentage of pyrite has only geochemically anomalous gold. This makes visual pyrite only a general grade control tool and not a specific tool This further makes the ore control process all the more difficult.\n

Materials

Ore mineralsGold, Electrum, Chalcopyrite, Galena, Silver

GangueQuartz, Pyrite, Siderite, Iron, Goethite, Sericite, Barite, Quartzite, Granite, Gneiss, Andesite, Shale, Dolomite

Geology

Host rockFelsic Volcanic Rock

Associated rockGneiss,Schist,Sedimentary Rock,Andesite

Tectonic settingThe Colosseum Mine is located at the southern end of the Sevier foreland thrust belt in the southern Basin and Range Province. Gold mineralization occurred about 100 Ma in earliest Late Cretaceous time (post-Sevier thrusting/pre-Basin and Range extensional tectonics), probably in association with one of several shallow-level, early Late Cretaceous stocks that appear to represent northeastern outliers of the magmatic belt that comprises the broadly calc-alkaline series of six plutons that comprise the Teutonia Batholith (Sharp, 1984; Haxel and Miller, 2006).

AlterationQuartz-sericite-pyrite

Economic & production

Development statusPast Producer

Discovery year1865

Identification

Deposit ID10310702

Alternate namesIvanpah Consolidated Mine

RegionNA

Data scoreA

Coordinates35.57, -115.56556

References

Beatty, R.L., 1989a, Bond Gold Colosseum Inc., crushing and grinding: an update: Society of Mining Engineers Preprint No. 89-85 for presentation at SME Annual Meeting, Las Vegas, NV Feb. 27 - Mar. 2, 1989, 6 pgs.Beatty, R.L., 1989b, Crushing and grinding at Bond Gold's Colosseum mine: an update: Society for Mining, Metallurgy, and Exploration, Mining Engineering, August 1989, pgs. 823-826.Britton, Vickie, 1986, Colosseum Mine plans to open: California Mining Journal, September 1986, pgs. 50-51.Burchfiel, B.C. and Davis, G.A., 1988, Mesozoic thrust faults and Cenozoic lowangle normal faults, eastern Spring Mountains Nevada, and Clark Mountains thrust complex, California in This Extended Land: Geological journeys in the southern Basin and Range, Field Trip[ guidebook, Geological Society of America, Western Cordilleran Section, Las Vegas, Nevada, p. 8710.California Polytechnic University - Pomona (CSU), site visited August 2006, Colosseum Mine in Ivanpah Mining District: CSU Geological Sciences Department, Pomona, http://geology.csupomona.edu/drjessey/fieldtrips/mtp/coloss.htm.Davis, B.M., Trinble, J., and McClure, D., 1989, Grade control and ore selection practices at the Colosseum gold mine: Society for Mining, Metallurgy, and Exploration, Mining Engineering, August 1989, pgs. 827-830.Dingwall, Laima, 1986, Aussie-made for N. America new Colosseum Gold Mines: Northern Miner, July 21, 1986.Dobbs, P.H., 1961, Geology of the central part of the Clark Mountain range, San Bernardino County, California, Unpublished M.S. Thesis, University of Southern California, 116p.Ely, Marion, 1982, Notice of reclamation plan completion, new Colosseum mine: Notice dated January 5, 1982, and submitted to the California Division of Mines and Geology; copy contained in CGS (formerly CDMG) Minefile Folder No. 322-5560.Garside, L.J., and Bonham, H.F., Jr., 1987, Precious metal deposits in southeastern California and southern and west-central Nevada in Johnson, J.L., Ed., 1997, A Symposium on Bulk Mineable Precious Metal Deposits of the Western United States, Guidebook for Field Trips, Field Trip 2: Geological Society of Nevada, April 6-8, 1987, Symposium, Field Trip 2, pgs. 70-71.Haxel, G. B., and Miller, D. M., 2006, Mesozoic rocks: Internet site, http://www2.nature.nps.gov/geology/USGSNPS/mojave/MESOmoja.pdf.Hewett, D.F., 1956, Geology and mineral resources of the Ivanpah Quadrangle, California and Nevada: U. S. Geological Survey Professional Paper 275, 172 p.Hill, R.L., 1998, Gold in the California desert, past, present, and future: California Division of Mines and Geology (aka California Geological Survey), California Geology, vol. 51, no. 1, pgs. 14-25.http://www.epa.gov/epaoswer/other/mining/techdocs/gold.htm; Chapter 3: Site Visit Report: Colosseum Mine [PDF, 48 pages, 578 KB]; http://www.epa.gov/epaoswer/other/mining/techdocs/gold/goldch3.pdf.McClure, D.L., and Schull, H.W., 1988, Colosseum Gold Mine, Clark Mountain range, San Bernardino County, California: Society of Mining Engineers Preprint Number 88119, SME Annual Meeting, Phoenix, AZ, 4p.Mining Engineering, September 1987, US and International Mineral News Briefs, pg. 844.Moyle, P.R., and Cather, E.E., 1992, Colosseum mine another new discovery in U.S. Bureau of Mines Open File Report 62-92, pgs. 38-43.Portions of various unpublished reports, and information from various Internet websites, contained in CGS (formerly CDMG) Minefile Folder No. 322-5560.Sharp, J.E., 1984, A gold mineralized breccia pipe complex in the Clark Mountains, San Bernardino County, California: Arizona Geological Society Digest, Vol. 15, pgs. 119-139.Skillings Mining Review, Feb. 21, 1987, pg. 7.Sunshine Mine Files, Colosseum Mine, Box #3, housed with CGS (formerly CDMG) Minefile Data.Tucker, W.B. and Gowman, C.H., December 29, 1942, Field Report No. 371: State Mining Bureau in CGS Minefile Folder #322-5560.U. S. Environmental Protection Agency, 2006, Technical Resource Document: Extraction and Beneficiation of Ores and Minerals: GoldU.S. Environmental Protection Agency (EPA), 1992, Site Visit Report: Colosseum Mine: U.S. EPA, Office of Solid Waste, 401 M Street SW, Washington, DC 20460, 47 pgs.