Fluor performed the early feasibility studies for the preliminary mine development including the shaft sinking, and ultimately took overall responsibility for engineering, procurement and construction of the L-Bar underground mine, laboratory and mill complex. Fluor was responsible for the design and installation of the mine surface facilities and the underground permanent facilities for the L-Bar mine, including the head frame, the hoist house, offices, and the change rooms.
Powered by a 250-horsepower mill, semi-autogenous grinding is used in this process. The uranium bearing ore is crushed and ground and then after cycloning, is pumped into two slurry storage tanks, then into the mechanically agitated leach tanks. All of these tanks are insulated to assist in temperature control. Leaching is followed by solid-liquid separation, which takes place in six counter-current thickeners. The process continues to the solvent extraction units and yellow cake drier and drum filling.
The Sohio counter-current washing thickener circuit has two pump stations, versus the typical central design concept. A tunnel for pipework, constructed from corrugated steel conduit with a concrete-filled base walkway, connects the two pump houses. The thickener tunnels use a similar design, which is considerably more economical than the conventional concrete arch and allows for easy maintenance.
Another design savings is the plant automation. With three control consoles, one for the grinding, one for the counter-current washing, and one for the solvent extraction and yellow cake handling combined, the Sohio plant requires only four operators.
Fluor's stringent focus on construction safety efforts netted 56 awards for the zero lost-time accidents performance.
The large endemic rattlesnake population was unique to this project and required snakebite kits in all the site trucks. No snakebites were recorded.