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Emma Mine

Past Producer in Dolores county in Colorado, United States with commodities Gold, Silver, Lead, Coal, Copper, Zinc
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Sections on this page
  1. Identification information
  2. Geographic coordinates
  3. Site location context
  4. Geographic areas
  5. Public Land Survey System information
  6. Commodities
  7. Materials information
  8. Host and associated rocks
  9. Nearby scientific data
  10. Geologic structures
  11. Ore body information
  12. Controls for ore emplacement
  13. Economic information about the deposit and operations
  14. Mining district
  15. Land status
  16. Ownership information
  17. Production statistics
  18. Links to other databases
  19. Bibliographic references
  20. General comments
  21. Reporter information

Geologic information

Identification information

Deposit ID 10014230
MRDS ID D010905
Record type Site
Current site name Emma Mine
Alternate or previous names Patented Claims: Great Bear, MS 12930, Lion, MS 12930, Sirius, MS 12931, Little Emma, MS 12951a, Orion, MS 12953a, Brooklyn, MS 18498, May Flower, MS 18499, Unpatented Claims: Emmarette, Barbara, Patricia, Cynthia, Modern, Queenmary, Modern Gold, Modern Mines, Normandic, Emmarette Mill Site, Modern Gold Mill Site, Modern Mines Mil Site
Related records 10166487

Geographic coordinates

Geographic coordinates: -108.09843, 37.76723 (WGS84)
Elevation 2688
Relative position 6.3 MILES N 36 W FROM RICO

Site location context

Political divisions (FIPS codes)

Dolores(county)

Colorado(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Dolores Peak(quadrangle 1:24,000 scale)

Dove Creek(quadrangle 1:100,000 scale)

Cortez(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Upper Dolores(hydrologic unit)

Upper Colorado-Dolores(hydrologic accounting unit)

Upper Colorado-Dolores(hydrologic subregion)

Upper Colorado(hydrologic region)

Federal lands

San Juan National Forest(National Forest)

National Forest FS(Type of land area)

FS(Federal land areas administered by FS)

Geographic areas

Country State County
United States Colorado Dolores

Public Land Survey System information

Meridian Township Range Section Fraction State
New Mexico 041N;040N 011W;011W 19,20,29,30,32;04,05 Colorado

Comments on the location information

  • (LAND STATUS AND ADMINISTRATIVE AREA LOCATIONS CALCULATED USING GIS OVERLAY ANALYSIS FOR SAN JUAN N. F.). MINE LOCATED ON SOUTH SIDE OF WEST DOLORES RIVER 0.45 MILE BELOW DUNTON. CLAIMS EXTEND ALONG EMMA FAULT SE BETWEEN EAGLE CREEK AND FALL CREEK AND NW ACROSS WEST DOLORES RIVER. EMMA COAL BANK WORKINGS LIE EAST OF FALL CREEK AT CONFLUENCE OF WEST AND EAST FORKS. ELEV AND LAT-LONG GIVEN ARE FOR EMMA SHAFT (SE SE SEC. 32). ; INFO FROM LAND.ST :1975

Commodities

Commodity Importance
Gold Primary
Silver Primary
Lead Primary
Coal Secondary
Copper Tertiary
Zinc Critical Tertiary

Materials information

Materials Type of material
Argentite Ore
Chalcopyrite Ore
Coal Ore
Galena Ore
Polybasite Ore
Pyrargyrite Ore
Pyrite Ore
Sphalerite Ore
Barite Gangue
Epsomite Gangue
Gypsum Gangue
Melanterite Gangue
Quartz Gangue

Host and associated rocks

  • Host or associated Associated
    Rock type Plutonic Rock > Mafic Intrusive Rock > Gabbro
    Rock unit name Microgabbro;Lamprophyre
    Rock description Microgabbro;Lamprophyre
    Stratigraphic age (youngest) Pliocene
  • Host or associated Associated
    Rock type Plutonic Rock > Porphyry > Lamprophyre
  • Host or associated Host
    Rock type Sedimentary Rock > Clastic Sedimentary Rock > Shale
  • Host or associated Host
    Rock type Sedimentary Rock > Clastic Sedimentary Rock > Sandstone
    Rock unit name Dolores Formation;Dakota Sandstone
    Rock description Dolores Formation;Dakota Sandstone

Nearby scientific data

(1) -108.09843, 37.76723
ListMap

Economic information

Geologic structures

Type of structure Regional
Structure description San Juan Uplift, Paradox Basin
Type of structure Local
Structure description Rico Dome, Dunton Syncline, Emma Fault

Ore body information

  • Thickness 1.22M

Controls for ore emplacement

  • Fissure Vein In Bounding Graben Fault

Economic information about the deposit and operations

Development status Past Producer
Commodity type Metallic
Deposit size Small
Significant No
Discovery year 1880
Discoverer John A. Gilmore
Year of first production 1885
Year of last production 1980

Mining district

District name Lone Cone (Dunton) District

Land status

Ownership category Private
Area name San Juan N. F.

Ownership information

  • Type Owner-Operator
    Owner Rado Reef Resources
    Home office Stoner, Co.
    First year 1980

Production statistics

  • Year 1913
    Description Ap_Grade: ^259.83 Oz/Ton Ag, 3.47 Oz/Ton Au
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Conc. Gold Gold 98g/mt
    Major Conc. Silver Silver 7336g/mt
  • Year 1913
    Description Ap_Grade: ^202.2 Oz/Ton Ag, 3.17 Oz/Ton Au
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Ore Gold Gold 90g/mt
    Major Ore Silver Silver 5709g/mt
  • Year 1913
    Description Ap_Grade: ^253.7 Oz/Ton Ag, 2.72 Oz/Ton Au
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Ore Gold Gold 77wt-pct
    Major Ore Silver Silver 7163g/mt
  • Year 1920
    Description Ap_Grade: ^100 Oz/Ton Ag, 0.68 Oz/Ton Au (Crude)
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Ore Gold Gold 19g/mt
    Major Ore Silver Silver 2824g/mt
  • Year 1921
    Description Ap_Grade: ^86.2 Oz/Ton Ag, 0.71 Oz/Ton Au, 3.5% Zn (Crude)
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Trace Zinc Zinc 4wt-pct
    Major Ore Gold Gold 1g/mt
    Major Ore Silver Silver 2434g/mt
  • Year 1922
    Description Ap_Grade: ^123.51 Oz/Ton Ag, 1.16 Oz/Ton Au (Crude)
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Ore Gold Gold 33g/mt
    Major Ore Silver Silver 3487g/mt
  • Year 1928
    Description Ap_Grade: ^50 Oz/Ton Ag, 0.1 Oz/Ton Au (Milling)
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Mill Ore Gold Gold 3g/mt
    Major Ore Silver Silver 1412g/mt
  • Year 1928
    Description Ap_Grade: ^100 Oz/Ton Ag, 2.4 Oz/Ton Au (Crude)
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Ore Gold Gold 68g/mt
    Major Ore Silver Silver 2824g/mt
  • Year 1928
    Description Ap_Grade: ^114 Oz/Ton Ag, 6.73 Oz/Ton Au, 2.2% Pb
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Lead Lead 2wt-pct
    Major Conc. Gold Gold 190g/mt
    Major Conc. Silver Silver 3219g/mt
  • Year 1929
    Description Ap_Grade: ^111 Oz/Ton Ag, 2.4 Oz/Ton Au (Crude)
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Ore Gold Gold 68g/mt
    Major Ore Silver Silver 3134g/mt

Comments on the workings information

  • MAP PREPARED BY RADO REEF RESOURCES (1979) SHOWS MINE TO BE DEVELOPED BY FOUR OR FIVE TUNNEL LEVELS AND 165-FT VERTICAL SHAFT OFF WHICH SIXTH LEVEL DEVELOPED. NO. 1 TUNNEL LOCATION AND EXTENT UNKNOWN. NO. 2 LEVEL DRIVEN GENERALLY SE OR SSE ALONG EMMA VEIN FOR AT LEAST 1850 FT. NO. 3 LEVEL LIES ABOUT 75 FT BELOW NO. 2, DRIVEN GENERALLY SE OR SSE ALONG EMMA VEIN FOR AT LEAST 160 FT. NO. 4 LEVEL LIES ABOUT 100 FT BELOW NO. 3, DRIVEN GENERALLY SE OR SSE ALONG EMMA VEIN FOR AT LEAST 2550 FT. NO. 5 LEVEL LIES ABOUT 100 FT BELOW NO. 4, DRIVEN GENERALLY SE OR SSE FOR AT LEAST 2800 FT, WITH SEVERAL WINZES. NO. 6 LEVEL LIES ABOUT 170 FT BELOW NO. 5, AND IS DRIVEN ABOUT 180 FT NORTH AND ABOUT 1330 FT SOUTH OF SHAFT AT DEPTH OF BETWEEN 140 AND 150 FT IN SHAFT. EMMA COAL BANK WORKINGS ARE ONE TUNNEL (ELEV 9920) DRIVEN GENERALLY SE, EXTENT UNKNOWN.

Reference information

Bibliographic references

  • 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

    BASTIN, E.S., 1922, SILVER ENRICHMENT IN THE SAN JUAN MOUNTAINS, COLORADO: USGS BULL. 735-D, P. 116-120.

  • Deposit

    COLORADO DIV. MINES INF. REPTS. AND ANNUAL OPERATOR REPTS.

  • Deposit

    BLM MINERAL SURVEYS MS 12930, 12931, 12951A, 12953A, 18498, 18499

  • 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.

  • Production

    BASTIN, 1922, P. 120 (1913 FIGURES); COLORADO DIV. MINES ANNUAL OPERATOR REPTS. (1920-1980 FIGURES)

General comments

Subject category Comment text
Deposit NORTH- AND NW-DIPPING DOLORES FM RED BEDS CUT BY GENERALLY NW-TRENDING EMMA FAULT, DIPPING 80 TO 85 NE, FORMING WEST BOUNDARY OF GRABEN; BEDS DIP NE WITHIN GRABEN NEAR MINE. SE OF MINE, GENERALLY NE- TO ENE-TRENDING CROSS FAULT INTERSECTS EMMA FAULT. JUST INSIDE EMMA HANGING WALL, MICROGABBRO DIKE TRENDS SUBPARALLEL TO EMMA FAULT AND DIPS 50 NE. BASTIN (1922) DESCRIBED VEIN AS UP TO 4 FT WIDE AND CONSISTING OF IRREGULAR QUARTZ VEINLETS AND CHALCOPYRITE, QUARTZ-LINED VUGS; IN PLACES ORE FILLS SPACES BETWEEN BRECCIA FRAGMENTS. KRANTZ AND FREEMAN (1923) DESCRIBED ORE AS SIMILAR TO THAT AT SMUGGLER MINE: SPHALERITE, PYRITE, GALENA, CHALCOPYRITE, AND ARGENTITE AS INCLUSIONS IN SPHALERITE; NONBANDED. POST-MINERALIZATION FRACTURES CUTTING ORE ARE FILLED WITH SECONDARY ORES PROUSTITE, PYRARGYRITE, CHALCOPYRITE, AND ARGENTITE. WARM WATERS RISING ALONG VEIN EVOLVED CO2, H2S, AND DEPOSITED FERRUGINOUS CALCITE AND VARIOUS SULFATES. BLEACHING EXTENDS 8 TO 10 FT BEYOND VEIN AND IS CHARACTERIZED BY
Deposit DISSEMINATED PYRITE. COAL MINED FROM THIN SEAMS IN DAKOTA SANDSTONE ON WEST LIMB OF DUNTON SYNCLINE WHERE INTRUDED BY AND POSSIBLY LOCALLY UPGRADED BY LAMPROPHYRE SILL.

Reporter information

Type Date Name Affiliation Comment
Reporter 01-SEP-1983 Schwochow, Stephen D. Colorado Geological Survey

Beyond USGS

Supplemental information added by qvyshift.com. Not part of the original USGS MRDS record.

External references

Maps centered on this site

Authoritative Colorado resources

These are landing pages for further research — the state agencies don't currently expose per-mine deep links.