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Incas Mine

Past Producer in La Plata county in Colorado, United States with commodities Gold, Silver, Lead, Copper, Zinc, Tellurium
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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. Alteration
  9. Mineral occurrence model information
  10. Host and associated rocks
  11. Nearby scientific data
  12. Geologic structures
  13. Ore body information
  14. Economic information about the deposit and operations
  15. Mining district
  16. Land status
  17. Ownership information
  18. Production statistics
  19. Links to other databases
  20. Bibliographic references
  21. General comments
  22. Reporter information

Geologic information

Identification information

Deposit ID 10087915
MRDS ID D010826
Record type Site
Current site name Incas Mine
Alternate or previous names Van Emmett Property, Patented Claims: Incas, MS 17117, Unexpected, MS 17118, Incas No. 1, MS 18511, Oriental, MS 18511, Incas No. 2, MS 18513, Incas No. 3, MS 18513, Northern Slope, MS 18513, Unexpected No. 1, MS 18513, Unexpected No. 2, MS 18513, Unexpected No. 3, MS 18513, Great Divide, MS 18513, Great Divide No. 2, MS 18513, Great Divide No. 3, MS 18513, Northern Knight, MS 18513, Moonlight, MS 18513, Gold Coin, MS 18740
Related records 10215486

Geographic coordinates

Geographic coordinates: -108.06009, 37.3664 (WGS84)
Elevation 3316
Relative position 11.6 MILES N 60 W FROM DURANGO

Site location context

Political divisions (FIPS codes)

La Plata(county)

Colorado(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Hesperus(quadrangle 1:24,000 scale)

Cortez(quadrangle 1:100,000 scale)

Cortez(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Middle San Juan(hydrologic unit)

Upper San Juan(hydrologic accounting unit)

San Juan(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 La Plata

Public Land Survey System information

Meridian Township Range Section Fraction State
New Mexico 036N 011W 15,21,22 Colorado

Comments on the location information

  • (LAND STATUS AND ADMINISTRATIVE AREA LOCATIONS CALCULATED USING GIS OVERLAY ANALYSIS FOR SAN JUAN N. F.). CLAIMS LIE NORTH OF LITTLE DEADWOOD GULCH ON TOP AND ON SE SIDE OF OHWILER RIDGE, 2.3 MILES SSE OF LA PLATA TOWNSITE (UNSURVEYED SECTIONS). ; INFO FROM LAND.ST :1974

Commodities

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

Materials information

Materials Type of material
Galena Ore
Gold Ore
Pyrite Ore
Sphalerite Ore
Ankerite Gangue
Calcite Gangue
Quartz Gangue

Alteration

  • (Local) Sericitization, Kaolinitization

Analytical data

Result CRUDE ORE MINED IN 1921-1922 CONTAINED 1 TO 1.465 OZ/TON AU AND 0.9TO 1.39 OZ/TON AG

Mineral occurrence model information

Model code 85
USGS model code 22c
Deposit model name Polymetallic veins
Mark3 model number 46

Host and associated rocks

  • Host or associated Associated
    Rock type Plutonic Rock > Mafic Intrusive Rock > Diorite
    Rock unit name Porphyritic Rocks--Diorite-Monzonite Porphyry
    Rock description Porphyritic Rocks--Diorite-Monzonite Porphyry
    Stratigraphic age (youngest) Paleocene
    Stratigraphic age (youngest) Paleocene
    Stratigraphic age (youngest) Late Jurassic
  • Host or associated Host
    Rock type Sedimentary Rock > Clastic Sedimentary Rock > Sandstone
  • Host or associated Host
    Rock type Sedimentary Rock > Carbonate > Limestone
    Rock unit name Pony Express Limestone Member Of Wanakah Formation;Entrada Sandstone
    Rock description Pony Express Limestone Member Of Wanakah Formation;Entrada Sandstone

Nearby scientific data

(1) Morrison, Wanakah, and Entrada Fms
ListMap

Economic information

Geologic structures

Type of structure Regional
Structure description San Juan Uplift, Four Corners Platform
Type of structure Local
Structure description La Plata Dome

Ore body information

  • Thickness 4.57M

Economic information about the deposit and operations

Development status Past Producer
Commodity type Metallic
Deposit size Small
Significant No
Discovery year 1904
Discoverer Van Emmett Gold Mining And Milling Co. (Incas And Unexpected Claimant)
Year of first production 1909
Year of last production 1922

Mining district

District name California (La Plata) District

Land status

Ownership category National Forest
Area name San Juan N. F.

Ownership information

  • Type Owner-Operator
    Owner Incas Mines, Inc.
    Home office Durango, Co.
    First year 1950

Production statistics

  • Year 1916
    Material AG ACC
    Description Ap_Grade: ^1.13 Oz/Ton Au
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Minor Gold Gold 32g/mt
  • Year 1916
    Material ORE AU AG ACC
    Description Ap_Grade: ^4.8 Oz/Ton Au
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Minor Ore Gold Gold 136g/mt
  • Year 1917
    Material AU ACC
    Description Ap_Grade: ^1.46 Oz/Ton Au
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Minor Gold Gold 41g/mt
  • Year 1921
    Material ORE AU AG ACC
    Description Ap_Grade: ^1.03 Oz/Ton Au
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Minor Ore Gold Gold 29g/mt

Comments on the production information

  • COMPLETE PRODUCTION RECORD. NO PRODUCTION REPORTED PRIOR TO 1909 OR FOR 1918-1920. AND AFTER 1922. ORE GRADES CITED ARE AVERAGE TENORS OF ORE REPORTED BY ECKEL AND OTHERS. FIGURES FOR 1911 INCLUDE SMALL AMOUNT OF PRODUCTION FROM GOLD COIN CLAIM.

Comments on the workings information

  • MINE DEVELOPED BY NOS. 1 AND 3 TUNNELS, COMBINATION TUNNEL, LOWER PRICE TUNNEL, NEW PRICE TUNNEL, MILLER TUNNEL, SHAFT, AND OPEN CUT. TUNNELS DRIVEN GENERALLY NORTH TO NW INTO EXTENSIVELY MINED AREAS. MILLER TUNNEL DRIVEN GENERALLY N 18 W FOR 660 FT WITH RAISES AT 245 FT, 325 FT, AND 660 FT FROM PORTAL. THIRD RAISE IS 43 FT HIGH, INCLINED AT 80 DEG, EXTENDING TO 190-FT NW-INCLINED UPPER LEVEL.

Comments on development

  • INCAS AND UNEXPECTED CLAIMS SURVEYED IN 1904 BY VAN EMMETT GOLD MINING AND MILLING CO., WITH REMAINING CLAIMS SURVEYED IN 1908. FIRST APPARENT PRODUCTION IN 1909, WITH INTERMITTENT PRODUCTION THROUGH 1922. NUGGET GOLD MINES DROVE CROSSCUT IN 1936-1937 TO DEVELOP VEINS AT DEEPER LEVELS.

Reference information

Bibliographic references

  • Deposit

    ECKEL, E.B., AND OTHERS, 1949, GEOLOGY AND ORE DEPOSITS OF THE LA PLATA DISTRICT, COLORADO: USGS PROF. PAPER 219, P. 73-76, 125-129.

  • Deposit

    COLORADO DIV. MINES INF. REPTS.

  • Deposit

    BLM MINERAL SURVEYS MS 17117, 17118, 18511, 18513, 18740

  • Production

    ECKEL AND OTHERS, 1949, P. 126 (AS COMPILED FROM USGS AND USBM RECORDS)

General comments

Subject category Comment text
Deposit COUNTRY ROCKS CONSIST OF SW-DIPPING JURASSIC SEDIMENTARY ROCKS INTRUDED BY DIORITE-MONZONITE PORPHYRY SILLS AND DIKES. FOUR MAIN VEINS OR MINERALIZED FAULT ZONES KNOWN AS EAST, BURRIS, BLOUNT, AND NO. 3 AND TREND NW; FIFTH ZONE, NO. 1, TRENDS NNW AND INTERSECTS OTHERS. VEINS CONSIST OF BRECCIATED, SHEETED SANDSTONE UP TO 15 FT WIDE, AVERAGING 3 FT. BRECCIA CONTAINS DISSEMINATED AU LOCALLY ASSOCIATED WITH PYRITE. ALTERED PONY EXPRESS LIMESTONE YIELDED MUCH OF ORE PRODUCED. IN UPPER LEVEL OF MILLER TUNNEL, 3-FT-THICK PONY EXPRESS MEMBER RECRYSTALLIZED TO COARSE-GRAINED MIXED CARBONATE. ORE APPEARS LOCALIZED AS REPLACEMENT IN LIMESTONE NEAR ITS COMMON INTERSECTION WITH VERTICAL VEIN AND EAST-TRENDING PORPHYRY DIKE. CRUSHED, MINERALIZED SANDSTONE (CORRESPONDING TO BILK CREEK MEMBER OF WANAKAH FM) ABOVE LIMESTONE ALSO PRESUMABLY MINED. DEEP NUGGET GOLD MINES TUNNEL DRIVEN TO CUT DOWNWARD EXTENSIONS OF VEINS BELOW WANAKAH AND ENTRADA, BUT APPARENTLY FRACTURES IN DOLORES FM (TRIASSIC) ARE
Deposit NARROW AND ONLY SLIGHTY MINERALIZED.

Reporter information

Type Date Name Affiliation Comment
Reporter 01-AUG-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.