Ashland-Ten Broeck Mines

Site Name

Primary: Ashland-Ten Broeck Mines
Secondary: Patented Claims: Ashland, MS 1109
Secondary: Ten Broeck, MS 19961
Secondary: Brawner, MS 19962
Secondary: Parole Extension, MS 19962
Secondary: Ashland Mine
Secondary: Ten Broeck Mine
Secondary: Brawner Crosscut Tunnel

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Commodity

Primary: Silver
Primary: Gold
Secondary: Copper
Secondary: Lead
Tertiary: Tellurium
Tertiary: Mercury

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Location

State: Colorado
County: La Plata
District: La Plata (California) District

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Land Status

Land ownership: National Forest
Note: the land ownership field only identifies whether the area the mine is in is generally on public lands like Forest Service or BLM land, or if it is in an area that is generally private property. It does not definitively identify property status, nor does it indicate claim status or whether an area is open to prospecting. Always respect private property.
Administrative Organization: San Juan N. F.

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Holdings

Not available

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Workings

Not available

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Ownership

Not available

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Production

Not available

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Deposit

Record Type: Site
Operation Category: Past Producer
Deposit Type: Vein
Operation Type: Underground
Year First Production: 1881
Year Last Production: 1917
Discovery Year: 1880
Discovery Method: Ore-Mineral In Place
Years of Production:
Organization:
Significant: N
Deposit Size: S

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Physiography

General Physiographic Area: Intermontane Plateaus
Physiographic Province: Colorado Plateaus
Physiographic Section: Navajo Section

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Mineral Deposit Model

Model Name: Polymetallic veins

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Orebody

Not available

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Structure

Type: R
Description: San Juan Uplift, Four Corners Platform

Type: L
Description: La Plata Dome, Lewis Mtn Diorite Stock

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Alterations

Alteration Type: L
Alteration Text: Silicification

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Rocks

Name: Diorite
Role: Associated
Age Type: Host Rock Unit
Age Young: Late Permian

Name: Diorite
Role: Associated
Age Type: Associated Rock
Age Young: Eocene

Name: Diorite
Role: Associated
Age Type: Host Rock
Age Young: Late Permian

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Analytical Data

Analytical Data: ASSAYS OF UPPER TEN BROECK LEVEL DRIFT: 0.02 TO 2.44 OZ/TON AU AND 0.71 TO 9.2 OZ/TON AG. LOWER TEN BROECK LEVEL DRIFT: NW FAULT, 0.15 TO 0.88 OZ/TON AU AND 0.15 TO 1.06 OZ/TON AG
Analytical Data: IN RAISE, 0.12 TO 0.7 OZ/TON AU AND 0.58 TO 2.4 OZ/TON AG. BRAWNER TUNNEL, TEN BROECK DRIFT ASSAYS: 0.06 TO 0.92 OZ/TON AU AND 0.30 TO 5.09 OZ/TON AG, WITH HIGHS OF 10.91 OZ/TON AU AND 9.5 TO 18.6 OZ/TON AG. BRAWNER TUNNEL, BUTTE DRIFT ASSAYS: 0.01 TO 0.84 OZ/TON AU WITH HIGH OF 2.5 OZ/TON AU, 0.5 TO 16.58 OZ/TON AG WITH HIGHS OF 30.3, 48.72, 67.94, AND 120.36 OZ/TON AG. ASHLAND ORE SHIPMENTS FROM 1908-1913 CONTAINED 1.53 TO 59.54 OZ/TON AU AND 4.29 TO 44.26 OZ/TON AG. TEN BROECK ORE SHIPMENTS FROM 1913-1917 CONTAINED 1.47 TO 21.56 OZ/TON AU AND 4.88 TO 57.10 OZ/TON AG.
Analytical Data: PART OF VEIN IN HANGING WALL, 0.16 TO 1.3 OZ/TON AU AND 2.53 TO 16 OZ/TON AG

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Materials

Ore: Chalcopyrite
Ore: Pyrite
Ore: Galena
Gangue: Chalcedony
Gangue: Barite
Gangue: Quartz

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Comments

Comment (Deposit): COUNTRY ROCKS CONSISTS OF CUTLER FM RED BEDS INTRUDED BY DIORITE-MONZONITE PORPHYRY SILLS AND DIORITE OF LEWIS MTN STOCK. VEIN TRENDS ABOUT N 55 W, DIPS AVERAGE 70 NE, AND IS COMPOSED OF SEVERAL OVERLAPPING SEGMENTS BROKEN BY CROSS-FRACTURES. MOST AU AND AG PROBABLY OCCURRED AS TELLURIDES, WITH LOCALLY ABUNDANT GALENA AND CHALCOPYRITE; EARLY REPORTS CITED OCCURRENCE OF NATIVE HG. VEIN MATTER CHIEFLY QUARTZ WITH SOME CHALCEDONY AND BARITE AND SCATTERED IRREGULAR MASSES OF PYRITE.

Comment (Location): (LAND STATUS AND ADMINISTRATIVE AREA LOCATIONS CALCULATED USING GIS OVERLAY ANALYSIS FOR SAN JUAN N. F.). ON SOUTH SLOPE OF LEWIS MTN AT HEAD OF WALLS GULCH, 3.15 MILES NE OF LA PLATA TOWNSITE (UNSURVEYED SECTION). ; INFO FROM LAND.ST :1974

Comment (Production): PARTIAL PRODUCTION RECORD. FIGURES UNKNOWN FOR 1881-1882, 1884-1886, 1889, 1891-1901. NO PRODUCTION REPORTED FOR 1902-1907, 1909, 1915-1916, AND AFTER 1917.

Comment (Development): VEIN DISCOVERED BEFORE 1880, AND INTERMITTENT PRODUCTION TOOK PLACE FROM 1881 TO 1890, AND AGAIN FROM 1908 TO 1917. BRAWNER TUNNEL DRIVEN 1917-1921.

Comment (Workings): TEN BROECK MINE DEVELOPED BY TWO TUNNELS. UPPER TUNNEL (920 FT ABOVE BRAWNER TUNNEL LEVEL) DRIVEN GENERALLY N 73 W FOR 85 FT TO VEIN, THENCE N 62 W FOR AT LEAST 160 FT INTO CAVED AREA; AT 75 FT FROM CROSSCUT IS 150-FT RAISE FROM LOWER LEVEL. LOWER PORTAL (770 FT ABOVE BRAWNER TUNNEL LEVEL) LOCATED 240 FT ESE FROM UPPER PORTAL, DRIVEN GENERALLY N 80 W FOR 140 FT; AT 105 FT FROM PORTAL, DRIFT DRIVEN GENERALLY N 60 TO 77 W FOR APPROX 480 FT TO CAVED AREA; AT 300 FT ALONG DRIFT ALONG DRIFT IS RAISE TO UPPER LEVEL. BRAWNER TUNNEL DRIVEN GENERALLY N 35 E FOR APPROX 1890 FT; AT 1780 FT FROM PORTAL, DRIFT DRIVEN ON PARDE VEIN N 50 W FOR 260 FT. AT 1760 FT FROM PORTAL, TEN BROECK DRIFT DRIVEN S 53 E FOR 530 FT, THENCE CONTINUING 250 FT AS SOUTH CROSSCUT; AT 530 FT ALONG DRIFT, BUTTE DRIFT DRIVEN GENERALLY S 63 E FOR 300 FT. SEVERAL SURFACE OPEN CUTS. Adits caved in 1989.

Comment (Orebody): Deleted record 10288550 gives info on the orebody: Type of Orebody #1 : SHEAR ZONE Shape of Orebody #1 : TABULAR Primary mode of Origin : HYDROTHERMAL

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References

Reference (Production): ECKEL AND OTHERS, 1949, P. 85 (AS COMPILED FROM GOVT. RECORDS)

Reference (Deposit): BLM MINERAL SURVEYS MS 1109, 19961, 19962

Reference (Deposit): Neubert and others, 1992, Mineral Appraisal of the San Juan National Forest, Colorado: USBM MLA 2-92, p. 111, fig. 39.

Reference (Deposit): ECKEL, E.B., AND OTHERS, 1949, GEOLOGY AND ORE DEPOSITS OF THE LA PLATA DISTRICT, COLORADO: USGS PROF. PAPER 219, P. 73-76, 85-88, PL. 15.

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