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Abandoned mines › California
Abandoned mine inventory

Abandoned mines in Orange County, California

Orange County, California has 142 mine and prospect features on USGS topographic maps published 1942–1997, including 20 mine openings (shafts, adits and air shafts) and 5 prospect pits; 4 of the features carry a name on the map. OSMRE's abandoned mine land inventory lists 1 problems in the county, 1 of them not yet reclaimed. MSHA's register carries 33 mines in the county with status Abandoned or Abandoned and Sealed.

Every mine and prospect feature the USGS digitized from historical topographic maps covering Orange 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)
142
Mine openings
20
OSMRE problems unreclaimed
1
MSHA mines marked abandoned
33
4 features carry a name5 prospect pits15 quadrangle maps, published 1942–1997 1 OSMRE problems, 0 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
    20 14.0%
  2. Prospect pits and trenches
    shallow exploration diggings that never became a mine
    5 3.5%
  3. Mines and surface workings
    labelled mines, open pits, strip mines, placer and hydraulic workings
    41 28.7%
  4. Quarries, gravel and borrow pits
    construction-material and industrial-mineral extraction
    67 46.9%
  5. Dumps, tailings, spoil and gob
    what mining left above ground
    10 7.0%
Named features on the maps4 named · from the USGS compilation
Name on map Feature
Black Star Coal Mine Mine Shaft
Claymont Clay Mine Adit
Old Dominion Mine Mine Shaft
Santiago Coal 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.

OSMRE abandoned mine land problems1 on inventory
Problem area Problem Status
Santiago (harris) Mine P3 Spoil Area In Reclamation

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 Abandoned33 on register
  1. 33870P-1
    Surface metal/non-metal · Ortiz Crushing Corporation · MSHA ID 0405664
    Abandoned
  2. 72080P-2
    Surface metal/non-metal · Ortiz Enterprises Inc · MSHA ID 0405665
    Abandoned
  3. 72113R-1
    Surface metal/non-metal · Ortiz Crushing Corporation · MSHA ID 0405666
    Abandoned
  4. Asbury El Toro Ltd
    Surface metal/non-metal · Asbury Contractors Inc · MSHA ID 0404147
    Abandoned
  5. Atwood
    Surface metal/non-metal · Conrock Company · MSHA ID 0401733
    Abandoned
  6. Dayton Trucking (Portable)
    Surface metal/non-metal · Dayton Trucking Inc · MSHA ID 0405342
    Abandoned
  7. El Toro Materials Co
    Surface metal/non-metal · El Toro Materials Co · MSHA ID 0402884
    Abandoned
  8. El Toro Plant
    Surface metal/non-metal · Blue Diamond Materials · MSHA ID 0401968
    Abandoned
  9. FST OGLEBAY NORTON
    Surface metal/non-metal · Fst Sand & Gravel Inc · MSHA ID 0405076
    Abandoned
  10. Hidden Hills Plant
    Surface metal/non-metal · G & M Trucking · MSHA ID 0405014
    Abandoned
  11. Huntington Beach Plant
    Surface metal/non-metal · Blue Diamond Materials · MSHA ID 0403426
    Abandoned
  12. Irvine Lake Rock Plant
    Surface metal/non-metal · Livingston Graham/Blue Diamond Materials · MSHA ID 0404085
    Abandoned
  13. Mission Viejo Clay Pit
    Surface metal/non-metal · Riverside Cement Company · MSHA ID 0400531
    Abandoned
  14. Mission Viejo Materials Incorporated
    Surface metal/non-metal · Mission Viejo Materials Inc · MSHA ID 0401842
    Abandoned
  15. Orange County Water District Sand P
    Surface metal/non-metal · Materials Transport Services Inc · MSHA ID 0404043
    Abandoned
  16. Orange Plant
    Surface metal/non-metal · Conrock Company · MSHA ID 0401737
    Abandoned
  17. Orange Plant
    Surface metal/non-metal · R J Noble Company · MSHA ID 0401918
    Abandoned
  18. Plant 3
    Surface metal/non-metal · North American Recycling and Crushing, LLC · MSHA ID 0405535
    Abandoned
  19. Portable Operation
    Surface metal/non-metal · Dalton Trucking Inc · MSHA ID 0404778
    Abandoned
  20. Portable Screen #1
    Surface metal/non-metal · L&G Portable Crushing and Materials, LLC · MSHA ID 0405915
    Abandoned
  21. Ranch Rock Capo
    Surface metal/non-metal · Ranch Rock Corporation · MSHA ID 0405444
    Abandoned
  22. Rc 1 Orange Plant
    Surface metal/non-metal · Blue Diamond Materials · MSHA ID 0401969
    Abandoned
  23. Reliable Crushing
    Surface metal/non-metal · Reliable Crushing Inc · MSHA ID 0404849
    Abandoned
  24. San Clemente Plant
    Surface metal/non-metal · Crestlite Aggregates Inc · MSHA ID 0400549
    Abandoned
  25. San Clemente Project
    Surface metal/non-metal · Guy F Atkinson Company · MSHA ID 0404382
    Abandoned
  26. San Juan Plant
    Surface metal/non-metal · Calmat Company · MSHA ID 0401738
    Abandoned
  27. Santiago Canyon Plant
    Surface metal/non-metal · Transit Mixed Concrete Company · MSHA ID 0402100
    Abandoned
  28. Star
    Surface metal/non-metal · Robertson's Ready Mix, Ltd. · MSHA ID 0401880
    Abandoned
  29. Trabuco Canyon Plant
    Surface metal/non-metal · California Non-Metallics · MSHA ID 0400542
    Abandoned
  30. TRP-Irvine Lake Plant
    Surface metal/non-metal · Calmat Company · MSHA ID 0405277
    Abandoned
  31. Villa Park Dam
    Surface metal/non-metal · Fst Sand & Gravel Inc · MSHA ID 0405006
    Abandoned
  32. West Coast Aggregate Supply Inc
    Surface metal/non-metal · West Coast Aggregate Supply, Inc · MSHA ID 0405678
    Abandoned
  33. Yorba Linda
    Surface metal/non-metal · Materials Transport Services Inc · MSHA ID 0404850
    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
Open Pit Mine or Quarry 18
Adit 16
Disturbed Surface 16
Gravel/Borrow Pit - Undifferentiated 12
Gravel Pit 11
Gravel Pit 10
Sand Pit 10
Open Pit Mine or Quarry 5
Gravel/Borrow Pit - Undifferentiated 5
Salt Evaporator 5
Prospect Pit 5
Tailings - Undifferentiated 4
Mine Shaft 4
Sand Pit 4
Clay Pit 3
Clay Pit 3
Quarry 3
Quarry 2
Sand and Gravel Pit 2
Borrow Pit 2
Open Pit Mine 2
P3 Spoil Area 1
Other counties in CaliforniaAll 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.