Mine detail: Lone Cone District

Previously called 'Gold Nugget Mill Site, MS 16240bOtsego Estension, MS 15746aOtsego Mill Site, MS 15746bOtsego, MS 15747aOtsego Extension Mill Site, MS 15747bGold Nugget, MS 16240aComo, MS 16246aComo Mill Site, MS 16246bHorlick, MS 17235aAlmont, MS 17235aYule, MS 17235aPriest, MS 17235aHeddle, MS 17235aSmuggler, MS 17235aLombard, MS 17235aDick, MS 17235aMount Pleasant Mill Site, MS 20539Dunton DistrictPatented Claims: Little Wounder, MS 1516Great Bear, MS 12930Lion, MS 12930Sirius, MS 12931Little Emma, MS 12951aDunton Mill Site, MS 12951bOrion, MS 12953aOrion Mill Site, MS 12953bLombard Mill Site, MS 17235bColumbia, MS 18486aAmerica, MS 18486aNil Desperandum, MS 18486aBrooklyn MS 18498Mayflower, Ms18499Susie, MS 18519Nettie, MS 18519Little May, MS 18519'

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Location

Lat / long:

37.77279, -108.09482

Resource(B)

Primary:	Silver, Gold, Copper, Lead
Secondary:	Coal
Tertiary:	Antimony, Manganese, Sulfur, Tellurium, Zinc
Ore:	Argentite, Chalcocite, Chalcopyrite, Coal, Galena, Polybasite, Pyrargyrite, Pyrite, Sphalerite, Stibnite, Tennantite
Gangue:	Barite, Chalcedony, Epsomite, Gypsum, Melanterite, Quartz, Rhodochrosite, Sulfur
Discovery year:	1880

Production

Operation type:	Unknown
Production size:	Small
Development status:	Producer
First production started:	1885
Last production ended:	1980

Geology

Host rock:	Dolores Formation;Cutler Formation
Host type:	Shale,Siltstone,Sandstone
Associated rock:	Microgabbro;Calico Peak Porphyry
Associated type:	Gabbro,Latite,Basalt
Structure:	San Juan Uplift, Paradox Basin, Rico Dome, Dunton Syncline, Calico Peak Anticline, Dunton Fault, Papoose Fault, Emma Fault, Almont Fault, Unnamed Faults
Tectonic:	Central Cordillera (Southern Rocky Mtns)
Alteration processes:	Silicification Of Sandstone Wall Rocks Near Fissures; Some Oxidayion Of Sulfide Ores

References

MRDS	D010908
DEP	10087921
Reference	{Deposit:: BUSH, A.L., AND BROMFIELD, C.S., 1966, GEOLOGIC MAP OF THE DOLORES PEAK QUADRANGLE, DOLORES AND SAN MIGUEL COUNTIES, COLORADO: USGS MAP GQ-536.}{Deposit:: PRATT, W.P., AND OTHERS, 1969, GEOLOGIC MAP OF THE RICO QUADRNAGLE, DOLORES AND NONTEZUMA COUNTIES, COLORADO: USGS MAP GQ-797.}{Deposit:: BASTIN,E.S., 1922, SILVER ENRICHMENT IN THE SAN JUAN MOUNTAINS, COLORADO: USGS BULL. 735-D, P. 116-129.}{Deposit:: KRANTZ, P.R., AND FREEMAN, W.H., 1923, A STUDY OF THE ORES OF DUNTON DOLORES COUNTY, COLORADO: COLORADO SCHOOL OF MINES THESIS T-503.}{Deposit:: HENDERSON, C.W., 1926, MINING IN COLORADO, A HISTORY OF DISCOVERY, DEVELOPMENT, AND PRODUCTION: USGS PROF. PAPER 138, P. 114-117.}{Deposit:: COLORADO DIV. MINES INF. REPTS. AND ANNUAL OPERATOR REPTS.}{Deposit:: BLM MINERAL SURVEYS}{Deposit:: MCKNIGHT, E.T., 1974, GEOLOGY AND ORE DEPOSITS OF THE RICO DISTRICT, COLORADO: USGS PROF. PAPER 723.}{Production:: HENDERSON, 1926, P. 117; MCKNIGHT, 1974, P. 6; USGS/USBM MINERAL RESOURCES OF U.S.; USBM MINERAL YEARBOOKS; COLO. DIV. MINES ANN. OPERATOR REPTS.}
Reporter	Schwochow, Stephen D.