Shirley Basin, located 68 miles south of Casper, Wyoming, had been a quiet grazing land before the discovery of uranium in the area.
At Shirley Basin, the ore averages from 0.25 percent to 0.30 percent uranium. At that yield, a very large amount of ore had to be processed to produce the highly concentrated final product of uranium oxide, or “yellow cake.”
The blended ore is crushed into fine sand and combined with water. This slurry is leached with sulfuric acid to produce a solution containing uranium and other impurities. After leaching and thickening, the uranium is removed from solution using fixed bed ion exchange where the impurities are removed. The resin ion exchange circuit is entirely controlled from this one location by a single operator. Next, the pure uranium-bearing solution is centrifuged to separate the uranium from the solution and dried into concentrated yellowcake. After filtration, the yellow cake is dried and shipped in 50 liter drums.
The weather at Shirley Basin is severe. There is usually a constant wind, which, combined with snow and the winter temperatures often reaching - 40 °F, can cause many construction problems.
Workers and employees to Shirley Basin commute daily typically a75-minute drive from their homes in Casper, Wyoming.
Fluor was tasked to design and automate the processing operations to minimize manpower requirements.
Lastly, prior to processing any ore in the new mill, 300 feet of overburden had to be removed to reach the uranium deposits in the open-pit mine. This stripping required removal of more than 22 million cubic feet of earth.