United States

Black Thunder Mine

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Mine TypeOpen Pit
  • Coal (thermal)
Mining Method
  • Dragline
  • Truck & Shovel / Loader
Production Start... Lock
Mine Life2036
ShapshotBlack Thunder Mine is one of the largest surface coal mining operations in North America.

The Black Thunder mining complex currently consists of four active pit areas and two active loadout facilities.


Arch Resources, Inc. 100 % Indirect
Thunder Basin Coal Co LLC (operator) 100 % Direct
Thunder Basin Coal Company LLC, a wholly owned subsidiary of Arch Resources Inc, owns and operates the Black Thunder mine.



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Deposit type

  • Sedimentary


Regional Geology
The Powder River Coal Basin, of northeastern Wyoming, lies entirely within the boundaries of the Powder River structural and topographic basin. Coal-bearing strata range in age from Upper Cretaceous in the Mesa Verde Formation to Eocene in the Wasatch Formation. The Powder River Coal Basin covers parts of Campbell, Converse, Crook, Natrona, Niobrara, Johnson, and Weston Counties and is the largest coal basin in Wyoming.

Sandstone is a major lithologic component of the overburden in the mine Area. Siltstone constitutes approximately 15 percent of the overburden by volume. Like the mudstone, it is uniformly textured with 20 to 55 percent silt, and generally 20 to 60 percent clay, the remainder being sand. It is light to medium gray in color and slightly more consolidated than mudstone. Like other overburden lithologic units, the siltstone is discontinuous and occurs interbedded with mudstone and sandstone. In some areas, it overlies coal.

Property Geology
The economically mineable coal in Campbell County occurs within the Tongue River Member of the Fort Union Formation. The Wyodak coal seam occurs at the top of the Fort Union Formation and is overlain by the Wasatch Formation. The coal is low sulfur, low ash, and is subbituminous C in rank. Surface mineable coal deposits occur along the north-northwesterly striking subcrop of the Wyodak coal seam. The coal seam subcrops on the eastern edge of the lease and dips about two to three degrees to the west, with some slight rolling. This seam contains multiple benches or plys of coal of variable thicknesses, although in some local areas, it becomes one seam that reaches a thickness in excess of 100 feet. Across the mine permit area, the Wyodak Seam ranges in thickness from 10 feet to 100 feet, averaging approximately 70 feet.

Deposit type
The Black Thunder Mine reserve area is a relatively flat lying sedimentary deposit of Paleocene Age. The Black Thunder Mine is actively mining a single coal seam, the Wyodak, that can be divided into multiple splits, the Upper and Main splits of the Wyodak Seam.



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Mining Methods


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Crushers and Mills


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Coal (thermal) tons 000000000000000000000000000000000000000071,134,60670,513,365
All production numbers are expressed as ROM coal.

Operational metrics

Coal tonnes mined 000000000000000000000000000000000069,689 k tons
Stripping / waste ratio 0000004.03 bcy/t

Production Costs

Commodity production costs have not been reported.


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Heavy Mobile Equipment


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Mine Management

Source Source
Job TitleNameProfileRef. Date
....................... Subscription required ....................... Subscription required Subscription required Mar 13, 2024
....................... Subscription required ....................... Subscription required Subscription required Mar 13, 2024

Total WorkforceYear
Subscription required 2023
Subscription required 2022
Subscription required 2021
Subscription required 2020
Subscription required 2019
Subscription required 2018
Subscription required 2017
Subscription required 2016
Subscription required 2015

Aerial view:


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