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Abandoned mines › Montana
Abandoned mine inventory

Abandoned mines in Phillips County, Montana

Phillips County, Montana has 154 mine and prospect features on USGS topographic maps published 1954–1984, including 48 mine openings (shafts, adits and air shafts) and 2 prospect pits; 8 of the features carry a name on the map. MSHA's register carries 14 mines in the county with status Abandoned or Abandoned and Sealed.

Every mine and prospect feature the USGS digitized from historical topographic maps covering Phillips County, every OSMRE abandoned mine land problem in the county, and every MSHA-registered mine here with status Abandoned. Named features are listed below; unnamed ones are counted by type. Locations are deliberately not shown: this page says what abandoned workings are in the county, not where to find them. They are dangerous and should not be entered.

Mapped mine features (USGS)
154
Mine openings
48
OSMRE problems unreclaimed
0
MSHA mines marked abandoned
14
8 features carry a name2 prospect pits36 quadrangle maps, published 1954–1984 0 MSHA mines abandoned and sealed
What the features are
  1. Mine openings
    shafts, adits, air shafts, portals and vertical openings: the ways into underground workings
    48 31.2%
  2. Prospect pits and trenches
    shallow exploration diggings that never became a mine
    2 1.3%
  3. Mines and surface workings
    labelled mines, open pits, strip mines, placer and hydraulic workings
    10 6.5%
  4. Quarries, gravel and borrow pits
    construction-material and industrial-mineral extraction
    92 59.7%
  5. Dumps, tailings, spoil and gob
    what mining left above ground
    2 1.3%
Named features on the maps8 named · from the USGS compilation
Name on map Feature
August Mine Adit
Beaver Mine Adit
Coal Hill Mine Adit
Gold Bug Mine Adit
Hawkeye Mine Adit
Linda K Mine Adit
Little Ben Mine Mine Shaft
Ruby Mine Adit

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.

MSHA-registered mines with status Abandoned14 on register
  1. 21 Portable Crusher
    Surface metal/non-metal · 21 Construction Inc · MSHA ID 2402806
    Abandoned
  2. Bishop Crusher
    Surface metal/non-metal · Bishop, Inc. · MSHA ID 2402603
    Abandoned
  3. District B Screen
    Surface metal/non-metal · Phillips County · MSHA ID 2402031
    Abandoned
  4. Malta Mine
    Surface metal/non-metal · American Colloid Company Minerals Group · MSHA ID 2401435
    Abandoned
  5. Malta Plant
    Facility metal/non-metal · American Colloid Company Minerals Group · MSHA ID 2401437
    Abandoned
  6. Malta Ready Mix Wash Plant
    Surface metal/non-metal · Malta Ready Mix, Inc. · MSHA ID 2400463
    Abandoned
  7. MRM crusher
    Surface metal/non-metal · Malta Ready Mix · MSHA ID 2402702
    Abandoned
  8. Pegasus Gold Corp/Zortman Mng Inc-Landus
    Surface metal/non-metal · Pegasus Gold Corp · MSHA ID 2401150
    Abandoned
  9. PORTABLE CRUSHER
    Surface metal/non-metal · Malta Ready Mix · MSHA ID 2401962
    Abandoned
  10. Portable Power Screen
    Surface metal/non-metal · Malta Ready Mix, Inc. · MSHA ID 2402700
    Abandoned
  11. SCREENING PLANT
    Surface metal/non-metal · Phillips County · MSHA ID 2401959
    Abandoned
  12. West Mine
    Surface metal/non-metal · American Colloid Company Minerals Group · MSHA ID 2401436
    Abandoned
  13. ZORTMAN MINING INC
    Surface metal/non-metal · Spectrum Engineering Inc · MSHA ID 2401450
    Abandoned
  14. Zortman Placer
    Surface metal/non-metal · Penhard Resources Inc · MSHA ID 2401627
    Abandoned

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

By source vocabularythe publishers' own terms
Feature type Features
Gravel Pit 53
Adit 46
Gravel Pit 39
Open Pit Mine 6
Open Pit Mine 4
Tailings - Undifferentiated 2
Mine Shaft 2
Prospect Pit 2
Other counties in MontanaAll counties →
How to read these numbers

A USGS feature is a symbol on a historical topographic map, there when the map was surveyed; it may since have been sealed, reclaimed, built over or reopened as a working mine, and the map does not say which. An OSMRE row is a problem the abandoned mine land program tracks, not a mine. An MSHA mine is a registered operation whose operator reported abandonment, a record that starts in the 1970s. The three overlap and are never added together. The county is assigned from each feature's coordinates against the Census 2023 county boundaries. The full method is on the national page.

Sources
  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.