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Abandoned mines › Wyoming
Abandoned mine inventory

Abandoned mines in Niobrara County, Wyoming

Niobrara County, Wyoming has 44 mine and prospect features on USGS topographic maps published 1974–1981, including 28 prospect pits. OSMRE's abandoned mine land inventory lists 7 problems in the county, 3 of them not yet reclaimed. MSHA's register carries 5 mines in the county with status Abandoned or Abandoned and Sealed.

Every mine and prospect feature the USGS digitized from historical topographic maps covering Niobrara 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)
44
Mine openings
0
OSMRE problems unreclaimed
3
MSHA mines marked abandoned
5
0 features carry a name28 prospect pits11 quadrangle maps, published 1974–1981 7 OSMRE problems, 4 reclaimed 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
    1 2.0%
  2. Prospect pits and trenches
    shallow exploration diggings that never became a mine
    28 54.9%
  3. Quarries, gravel and borrow pits
    construction-material and industrial-mineral extraction
    16 31.4%
  4. Dumps, tailings, spoil and gob
    what mining left above ground
    1 2.0%
  5. Other reclamation problems
    highwalls, subsidence, polluted or clogged water, fires, slides and gases in OSMRE's inventory
    5 9.8%
OSMRE abandoned mine land problems7 on inventory
Problem area Problem Status
Niob0001 P2 Dangerous Highwalls Reclamation Pending
Niob0001 P3 Pits Reclamation Pending
Potter Mine P2 Vertical Openings In Reclamation
Wstn1136 P2 Dangerous Highwalls Reclamation Completed
Wstn1136 P2 Dangerous Impoundments Reclamation Completed
Wstn1136 P3 Pits Reclamation Completed
Wstn1136 P3 Spoil Area Reclamation Completed

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.

MSHA-registered mines with status Abandoned5 on register
  1. BALD BUTTE QUARRY
    Surface metal/non-metal · Bald Butte Quarry · MSHA ID 4801399
    Abandoned
  2. Brown Pit
    Surface metal/non-metal · Niobrara County Road & Bridge · MSHA ID 4801691
    Abandoned
  3. Coffee Pit
    Surface metal/non-metal · Gilpatrick Construction Company Inc · MSHA ID 4801244
    Abandoned
  4. Limestone Quarry
    Surface metal/non-metal · Rissler & Mc Murry Company · MSHA ID 4801138
    Abandoned
  5. Pfister Pit
    Surface metal/non-metal · Gilpatrick Construction Company Inc · MSHA ID 4801247
    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
Prospect Pit 28
Gravel Pit 10
Gravel Pit 4
P2 Dangerous Highwalls 2
P3 Pits 2
Quarry 2
P2 Dangerous Impoundments 1
P2 Vertical Openings 1
P3 Spoil Area 1
Other counties in WyomingAll 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.