Mining Intelligence and News
United States

Sheep Mountain Complex

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Mine TypeOpen Pit & Underground
  • Uranium
Mining Method
  • Truck & Shovel / Loader
  • Room-and-pillar
Backfill type ... Lock
Mine Life... Lock
SnapshotThe Sheep Mountain Project consists of permitted open pit and underground extraction components and a planned processing facility to process extracted mineralized material which has not yet been permitted.

The Energy Fuels will continue to evaluate its options for processing Sheep Mountain mineralized material, including continuing to pursue permitting for a heap leach facility at the site, or determining whether arrangements can be made to process Sheep Mountain mineralized materials at a third-party processing facility. Submittal of the license application to the WDEQ-LQD for a heap leach processing facility at the site is on hold pending the Company’s evaluation of off-site processing options for this project. The project is currently on standby, pending completion of the evaluation of the processing options for the Sheep Mountain Project and improvement in market conditions. Additional work is subject to any actions the Company may take in response to general market conditions.
Related AssetsCongo Project, Sheep Project


Energy Fuels Inc. 100 % Indirect
The Sheep Mountain Project (Congo Pit and Sheep Underground) is held by the Company’s (Energy Fuels Inc.) subsidiary Energy Fuels Wyoming Inc.

Deposit type

  • Sandstone hosted


A primary component of the geology for the Sheep Mountain Project is the Battle Spring Formation. Battle Spring is Eocene in age. Prior to deposition of the Battle Spring Formation and subsequent younger Tertiary formations, underlying Paleocene, Cretaceous, and older formations were deformed during the Laramide Orogeny. During the Laramide Orogeny, faults, including the Emigrant Thrust Fault at the northern end of the project area, were active and displaced sediments by over 20,000 feet. Coincident with this mountain building event, Paleocene and older formations were folded in a series of echelon anticlines and synclines, generally trending from southeast to northwest. The Battle Spring Formation was deposited unconformably on an erosional landscape influenced by these pre-depositional features. Initial stream channels transporting clastic sediments from the Granite Mountains formed in the synclinal valleys.

The geologic setting of the Sheep Mountain Project is important in that it controlled uranium mineralization by focusing movement of the groundwaters, which emplaced the uranium into the stream channels, which had developed on the pre-tertiary landscape. The Battle Spring Formation and associated mineralization at the Sheep Mountain Project is bounded to the east by the western flank of the Sheep Mountain Syncline and to the west by the Spring Creek Anticline. To the north the system is cut off by erosion. To the south the Battle Spring continues into the northern portions of the Great Divide Basin.

Mineralization occurs throughout the lower A Member of the Battle Spring Formation and is locally up to 1,500 feet thick. The upper B Member is present only in portions of the project and may be up to 500 feet thick. Although arkosic sandstone is the preferred host, uranium has been extracted from all lithologies. Grade and thickness are extremely variable depending on whether the samples are taken from the nose or the tails of a roll front. Typically, the deposits range from 50 feet to 200 feet along a strike, five feet to eight feet in height, and 20 feet to 100 feet in width. Deposits in the Sheep Mountain Project area occur in stacked horizons from 7,127 feet in elevation down to 6,050 feet in elevation.

Most of the mineralization in the Crooks Gap District occurs in roll-front deposits. Roll fronts have an erratic linear distribution but are usually concordant with the bedding. Deposits have been discovered from the surface down to a depth of 1,500 feet. The two major uranium minerals are uranophane and autunite. Exploration drilling indicated that the deeper roll-type deposits are concentrated in synclinal troughs in the lower Battle Spring Formation. Three possible sources for uranium have been suggested: post-Eocene tuffaceous sediments, leached Battle Spring arkoses, and Precambrian granites. Structural controls of uranium occurrences along roll fronts include carbonaceous siltstone beds that provide a local reducing environment for precipitation of uranium-bearing minerals, and abrupt changes in permeability along faults, where impermeable gouge is in contact with permeable sandstones. Uranium has also been localized along the edges of stream channels and at contacts with carbonaceous shales.



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Mining Methods


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Crushers and Mills

Milling equipment has not been reported.



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CommodityUnitsAvg. AnnualLOM
Uranium M lbs 1.417
All production numbers are expressed as U3O8.

Operational metrics

Ore tonnes mined, LOM  ....  Subscribe
Tonnes processed, LOM  ....  Subscribe
* According to 2021 study.

Production Costs

Total cash costs Uranium (U3O8) USD  ....  Subscribe
Assumed price Uranium (U3O8) USD  ....  Subscribe
* According to 2021 study / presentation.

Operating Costs

OP mining costs ($/t mined) USD 34.3 *  
UG mining costs ($/t mined) USD  ....  Subscribe
Combined mining costs ($/t mined) USD  ....  Subscribe
Processing costs ($/t milled) USD  ....  Subscribe
Total operating costs ($/t milled) USD  ....  Subscribe
* According to 2021 study.

Project Costs

MetricsUnitsLOM Total
Initial CapEx $M USD  ......  Subscribe
Sustaining CapEx $M USD  ......  Subscribe
Total CapEx $M USD  ......  Subscribe
OP OpEx $M USD  ......  Subscribe
UG OpEx $M USD  ......  Subscribe
OP/UG OpEx $M USD  ......  Subscribe
Processing OpEx $M USD 143.6
Total OpEx $M USD  ......  Subscribe
Total Taxes $M USD  ......  Subscribe
Royalty payments $M USD  ......  Subscribe
Gross revenue (LOM) $M USD  ......  Subscribe
Pre-tax Cash Flow (LOM) $M USD  ......  Subscribe
After-tax Cash Flow (LOM) $M USD  ......  Subscribe
Pre-tax NPV @ 5% $M USD  ......  Subscribe
Pre-tax NPV @ 10% $M USD  ......  Subscribe
Pre-tax NPV @ 7% $M USD  ......  Subscribe
After-tax NPV @ 5% $M USD  ......  Subscribe
After-tax NPV @ 10% $M USD  ......  Subscribe
After-tax NPV @ 7% $M USD  ......  Subscribe
Pre-tax IRR, %  ......  Subscribe
After-tax IRR, %  ......  Subscribe
Pre-tax payback period, years  ......  Subscribe

Heavy Mobile Equipment

Fleet data has not been reported.


Mine Management

Job TitleNameProfileRef. Date
....................... Subscription required ....................... Subscription required Subscription required Dec 31, 2021
....................... Subscription required ....................... Subscription required Subscription required Apr 21, 2024

Total WorkforceYear
...... Subscription required 2021


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