Uranium mine in Nebraska opens using in situ leaching

Owners of the Crow Butte uranium mine joined their guests for a tour of operations and a country-style celebration to mark the Oct. 17 official opening of the mine, four miles from this prairie community.

Crow Butte is a joint venture operated by Ferret Exploration of Nebraska under an agreement with Ferret Exploration, First Holding, Geomex Minerals, Uranerz USA and Korea Electric Power. Geomex is a wholly owned subsidiary of Imperial Metals (TSE).

“Crow Butte was brought in on budget and under schedule, and is a tribute to the hard work and ability of Ferret Exploration,” Imperial Chairman Hugh Morris told guests.

“These are difficult times for uranium producers,” added Gerhard Glattes, chairman of Uranerz Exploration and Mining. “Only low-cost, efficient operations will survive, and Crow Butte fits this description.” During the past decade, uranium producers have faced production exceeding consumption, reactor cancellations, new trading mechanisms which accelerated the liquidation of inventories and the entry of Soviet and other non-traditional supply, and spot prices tumbling to all-time lows. The development of Crow Butte owes much to the fact that it is ideally suited to the application of in situ leach mining. Mining is something of a misnomer here, as the process is more akin to oil and gas water flood production methods because it is based on removing uranium from water circulated through the uranium deposit underground.

This process is considered low-cost and environmentally friendly relative to conventional underground and open pit mining techniques because it does not involve the movement and milling of substantial quantities of ore. As a result, capital costs are much lower than traditional operations. Crow Butte is particularly well suited to the process because it has impermeable strata above and below the orebody, and a high degree of permeability in the ore zone proper. And the uranium mineralization occurs as a coating around individual sand grains in a sandstone rock formation, which enables the uranium to easily “go into solution.”

At Crow Butte, the mining process involves injecting a solution of water, oxygen and sodium bicarbonate through a series of drill holes similar to standard water wells, at depths of 400-800 ft.

The solution dissolves the uranium which is then pumped to the surface through recovery wells. At the recovery plant, the uranium is extracted from the groundwater using resin collectors in an ion exchange process. The ground water is fortified with oxygen and sodium bicarbonate and is pumped back to the wellfield in a continuous cycle, while the recovered uranium is concentrated and precipitated out as yellowcake, or natural uranium. The yellowcake is then shipped as slurry (50% moisture content) to a refining facility for final processing.

The joint venture participants won’t reveal production costs, as is typical in the industry, because contract negotiations with potential long-term buyers are still being finalized. But Morris did say the project is operating at break-even, and should produce uranium oxide at prices equal to or below current spot prices once full production is achieved.

The highly mechanized operation appears to be efficient and well managed, employing only 23 people, mostly local residents. The tour included a stop at a central control room which features a sophisticated computerized system which monitors all facets of the operation, from the wellfields to the process plant.