Overview

Mine Type	In-Situ
Status	Care and Maintenance
Commodities	Uranium
Mining Method	Solution mining
Production Start	...
Snapshot	Due to market conditions, Cameco curtailed production at Smith Ranch-Highland operation and deferred all wellfield development during the second quarter of 2016. As a result of 2016 decision, commercial production at the US operations ceased in 2018. Cameco do not expect any production in 2024.

Deposit type

• Sandstone hosted

Summary:

The uranium ore deposits at Smith Ranch occur at depths of 61 to 366 meters (200 to 1,200 feet) below surface. The ore is hosted in fluvial, arkosic sandstones of the Paleocene Fort Union and Eocene Wasatch Formations. The Fort Union and Wasatch Formations are locally separated by a laterally prevalent coal seam known as the School Coal. Individual host sand units have been correlated and named, and are separated by semi-continuous, confining layers usually composed of shale, siltstone or claystone. The Tertiary sediments dip gradually toward the Powder River Basin syncline (generally 0 to 5 degrees). Faulting in these Tertiary sediments is rare.

In cross-section, redox fronts, also called roll fronts, generally form C-shaped rolls, concaving toward the oxidized side of the roll front. In plan view, mineralization occurs in sinuous redox fronts within the host sandstones. The best ore accumulations typically occur where the redox fronts are the most sinuous. Hematite and limonite coatings on sand grains are prevalent on the oxidized side of the front, and feldspars have been totally or partially altered to kaolinite. Sands on the oxidized side of the front are generally orange to red to brown in color. There is virtually no uranium on the oxidized side of the roll front, although there may be a false radiometric uranium signature resulting from remnant radium and radium daughter products. Thorium and thorium daughter products are typically not mobilized by the ISR fluids.

On the reduced side of the roll front, the feldspars are unaltered. Reductants such as carbonaceous materials (lignite) and reduced mineral forms such as pyrite may also be present. The host sands on the reduced side of the roll front are usually gray to green-gray in color. The economically recoverable uranium mineralization is concentrated on the reduced side of the roll front, which at Smith Ranch and North Butte typically results in uranium ore thicknesses ranging from approximately 1 to 8 meters (2 to 25 feet).

The two most common uranium ore minerals are uraninite (U02) and coffinite [U(Si04)1-X(OH)4X] which occur as precipitated coatings on the sand grains. These minerals both contain uranium in the +4 valence (or reduced) state. The chemical reduction of the uranium during ore emplacement is accomplished by the interaction of the oxidized ore-bearing groundwater with organic carbon and pyrite that were naturally present within the sandstones near these redox boundaries.

At Smith Ranch, the shallower ore deposits are contained within the Q-Sand at approximate depths of 137 to 152 meters (450 to 500 feet) below the surface. At the Reynolds Ranch Satellite area, the shallower ore deposits are contained within the U/S Sand at approximate depths of 116 to 160 meters {380 to 525 feet) below the surface. Most of the remaining economic uranium mineralization at Smith Ranch and Reynolds Ranch occurs in the 0-Sand at approximate depths of 213 to 274 meters (700 to 900 feet) below the surface. These ore body sands are synonymous with the 30, 40, 50, and GO-Sands at Highland.

Mining Methods

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Comminution

Crushers and Mills

Processing

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Production

Personnel

Job Title	Name	Phone	Email	Profile	Ref. Date
.......................	.......................		...........		Mar 1, 2024
.......................	.......................	...........	...........		Aug 19, 2022
.......................	.......................		...........		Mar 1, 2024

Employees	Year
......	2016