Abandoned mines in San Juan County, Colorado

1. Mine openings

   shafts, adits, air shafts, portals and vertical openings: the ways into underground workings
   1,323 33.8%
2. Prospect pits and trenches

   shallow exploration diggings that never became a mine
   2,578 65.8%
3. Mines and surface workings

   labelled mines, open pits, strip mines, placer and hydraulic workings
   3 0.1%
4. Quarries, gravel and borrow pits

   construction-material and industrial-mineral extraction
   1 0.0%
5. Dumps, tailings, spoil and gob

   what mining left above ground
   7 0.2%
6. Mills, tipples and facilities

   processing plants and hazardous structures
   6 0.2%

A name is the label printed beside the symbol on the map. "First mapped" is the earliest topographic edition that shows the symbol, which bounds the feature's age from above; it is not the date it was worked. Unnamed features (most prospect pits, adits and shafts carry no label) are in the counts above but not this list.

Problem types carry OSMRE's priority prefix: P1 and P2 are threats to health, safety and property, P3 is environmental. A problem area is a cluster of problems reclaimed as one project; several rows can share one location.

1. Anglo Saxon #2

   Underground metal/non-metal · Pandora Mining Company · MSHA ID 0503091
   Abandoned 1982-06-08
2. Animas Aggregate Supply, LLC

   Surface metal/non-metal · Animas Aggregate Supply, LLC · MSHA ID 0505137
   Abandoned 2022-02-10
3. Auburn Mine

   Underground metal/non-metal · Auburn Mining Corp · MSHA ID 0503087
   Abandoned 1980-03-04
4. Bakers Park Mill

   Facility metal/non-metal · Bakers Park Mining & Milling Company · MSHA ID 0502549
   Abandoned 1982-01-26
5. Barlow Pit

   Surface metal/non-metal · Hilco Rock Inc · MSHA ID 0504074
   Abandoned 1991-09-17
6. BROOKLYN MINE

   Underground metal/non-metal · Golden Arrow Mining Inc · MSHA ID 0504584
   Abandoned 1998-01-09
7. Buffalo Boy Mine

   Underground metal/non-metal · Buffalo Boy Mining Company Inc · MSHA ID 0502610
   Abandoned 1985-04-23
8. Elk Park Mine

   Underground metal/non-metal · Minco Inc · MSHA ID 0503500
   Abandoned 1982-10-26
9. Ensle'S Prospect

   Underground metal/non-metal · Wide West Inc/Burbank*Gold Ltd · MSHA ID 0504403
   Abandoned 1990-02-09
10. Esmeralda

    Surface metal/non-metal · San Juan Milling Company · MSHA ID 0503113
    Abandoned 1981-06-17
11. Ezra-R Mine

    Underground metal/non-metal · Animas Canyon Mining Company · MSHA ID 0503467
    Abandoned 1983-08-12
12. Freda Claim

    Underground metal/non-metal · Triple L Mining · MSHA ID 0503693
    Abandoned 1985-07-08
13. Gold King Mine

    Underground metal/non-metal · Gold King Mines Corp · MSHA ID 0504057
    Abandoned 1990-07-26
14. Hawkeye Mine

    Underground metal/non-metal · Farmer Sickells Mining Co Of Redval · MSHA ID 0502805
    Abandoned 1979-08-27
15. Henrietta Mine

    Underground metal/non-metal · Henrietta Mines Inc · MSHA ID 0501382
    Abandoned 1981-06-17
16. Jack Knife Mine

    Underground metal/non-metal · Williams Inc · MSHA ID 0503067
    Abandoned 1981-06-17
17. Jones Mining & Pet Mill

    Facility metal/non-metal · Jones Mining & Pet Inc · MSHA ID 0503026
    Abandoned 1979-01-19
18. Little Giant

    Underground metal/non-metal · Little Giant Mining Company · MSHA ID 0502611
    Abandoned 1976-07-01
19. Little Ida Mine

    Underground metal/non-metal · Frank Montonati Mining Company · MSHA ID 0503212
    Abandoned 1979-08-27
20. Little Maude

    Underground metal/non-metal · Little Maude Inc · MSHA ID 0503081
    Abandoned 1985-08-16
21. Mayflower Mill

    Facility metal/non-metal · Sunnyside Gold Corp · MSHA ID 0503841
    Abandoned 1986-06-02
22. Minnehaha

    Underground metal/non-metal · Durango Gold Company Inc · MSHA ID 0503685
    Abandoned 1982-07-22
23. Old Hundred Mine

    Underground metal/non-metal · Asamera Minerals (Us) Inc · MSHA ID 0503736
    Abandoned 1982-06-02
24. Osceola-Pride Mine

    Underground metal/non-metal · P & G Mining Inc · MSHA ID 0503428
    Abandoned 1982-10-26
25. Portable Wash Plant No. 1

    Surface metal/non-metal · Mountain Stone Inc. · MSHA ID 0504823
    Abandoned 2008-05-09
26. PRIDE OF THE WEST ML SILVER WING CO. INC

    Facility metal/non-metal · SILVER WING CO., INC. · MSHA ID 0503760
    Abandoned 2004-06-30
27. Ruby Mine

    Underground metal/non-metal · Choctaw Mining Company · MSHA ID 0503176
    Abandoned 1980-02-14
28. San Diego Tunnel

    Underground metal/non-metal · Noranda Exploration Inc · MSHA ID 0503189
    Abandoned 1980-02-29
29. Silverton #1

    Surface metal/non-metal · Brian Fullmer Construction LLC · MSHA ID 0504903
    Abandoned 2009-12-11
30. Sultan Mountain Mill

    Facility metal/non-metal · Sultan Mountain Mine · MSHA ID 0503726
    Abandoned 1990-10-31
31. Sultan Mountain Mine

    Underground metal/non-metal · Sultan Mountain Mine · MSHA ID 0503740
    Abandoned 1989-01-27
32. Sunnyside Mine/Mayflower Mill

    Underground metal/non-metal · Sunnyside Gold Corp · MSHA ID 0500417
    Abandoned 1993-09-15
33. Treasure Mountain Projuct

    Underground metal/non-metal · Noranda Exploration Inc · MSHA ID 0503680
    Abandoned 1982-07-21
34. Valley Forge Mine

    Underground metal/non-metal · Z M K Mining Company · MSHA ID 0503174
    Abandoned 1981-08-18
35. Yukon Mill

    Facility metal/non-metal · Arrigo Milling & Mining · MSHA ID 0502142
    Abandoned 1983-02-07

Status and date are as reported to MSHA by the operator. Each mine's own page carries its accident, citation and inspection record.

• Lake County 3,672
• Gunnison County 2,703
• Saguache County 2,319
• San Miguel County 2,242
• Gilpin County 2,148
• Montrose County 2,077
• Custer County 2,062
• Clear Creek County 1,996
• Park County 1,624
• Chaffee County 1,486
• Summit County 1,449
• Boulder County 1,083

1. USGS, Consolidated Prospect- and Mine-Related Features from 7.5- and 15-Minute Topographic Quadrangle Maps of the United States (USMIN)
   597,612 point and area features digitized from about 106,350 historical topographic maps published 1886–2006; public domain (CC0). A feature is a map symbol, not a field-verified site, and the map does not say whether it was still worked.
2. USGS Fact Sheet 2025–3003, The Abandoned Mine Inventory of the United States
   States that as of 2025 there is no comprehensive national inventory of abandoned mine features, and that the detailed national database now being built will not be published.
3. OSMRE, Abandoned Mine Land Inventory System (e-AMLIS), public Problems layer
   One row per abandoned mine land problem in a problem area, with its type, funding program and reclamation status; mostly coal mined before the 1977 Surface Mining Control and Reclamation Act. Coordinates are the problem area's.
4. MSHA, Mines dataset (Mine Data Retrieval System)
   Every mine registered with MSHA since the 1970s; a mine reads Abandoned or Abandoned and Sealed when its operator reported that status. Refreshed weekly.
5. US Census Bureau, 2023 cartographic county boundaries (1:500,000)
   Each feature's county is assigned by its coordinates against these boundaries, not copied from the source file.
6. GAO-20-238, Abandoned Hardrock Mines (March 2020)
   Federal agencies had identified at least 140,000 abandoned hardrock mine features on federal land and estimated more than 390,000 more not yet captured in their databases.
7. Abandoned Hardrock Mine Reclamation (AHMR) Program, US Department of the Interior
   The program the USGS inventory is compiled for. Its appropriations and the 674,000 field-confirmed feature count on this page were provided by the program manager, Office of Environmental Policy and Compliance, and are cited with permission (2026-09-08).
8. IMCC-NAAMLP Hardrock AML Report
   Page 48 carries the two figures this page leans on: USGS estimates 633,181 of the 725,690 mine features it recorded from historic topographic maps, 87 percent, are hardrock; and state and federal agencies have submitted more than 724,000 AML features to the national database being built, already more than the historic maps hold. Year-by-year AHMR funding is on page 35.