Uranium deposits in the Centennial Project are sandstone, roll front type typical of those in Wyoming, South Dakota and Texas. These type deposits are usually “C” shaped in cross section, a few tens of feet-to-100 or more-feet wide and often thousands of feet long. Uranium minerals are usually deposited at the interface of oxidizing solutions and reducing solutions or redox boundaries. Typical alteration associated with this redox boundary consists of limonitic and hematitic staining of the sandstones.

As the uranium minerals precipitate, they coat sand grains and fill the interstices between grains. As long as oxidizing groundwater movement is constant, minerals will be solubilized in the interior portion of the “C” shape, and precipitated in the exterior portion of the “C” shape, increasing the tenor of the ore body by multiple migration and accretion. The thickness of the ore body is generally a factor of the thickness of the sandstone host unit. Mineralization may be 10 to 15ft thick within the roll front while being inches to feet thick in the tail portions.

Ore mineralogy consists of uraninite, pitchblende, coffinite, and carnotite, with associated vanadium in some deposits. Typical alteration in the roll-front sandstone deposit includes oxidation of iron minerals up-dip from the front and reduction of iron minerals down-dip along advancing redox interface boundaries.

The Centennial mineralization is located at depths of 100 to 500 feet below surface, as primarily three separate mineralized horizons, which are sinuous and narrow but extend for several miles along trend. The deposits are planned for ISR mining by development of individual well fields for each mineralized horizon. A well field will be developed as a series of injection and recovery wells, with a pattern to fit the mineralized horizon, typically a five-spot well pattern on 70 to 100 foot (ft) drillhole spacing depending on local hydrogeologic character.

The Centennial Project has two sections, the Northern project area and the Southern project area, both of which will be developed for ISR mining. The Northern deposits are located below the water table in the host formations with conditions favorable for ISR methods. Much of the mineralization in the Southern project area lies at or just above the water table, which will require a localized enhancement of the water table with a well field encircling freshwater injection fence to facilitate ISR mining methods.

A Central Processing Plant (CPP) will be constructed in the Northern project area, and a satellite facility (SF) in the Southern project area. The SF will only contain ion exchange vessels for resin loading, and the loaded resin will be hauled by truck to the CPP. The central uranium recovery and processing plant is planned to produce uranium as “yellowcake”.

Total recovery of uranium from the mineral deposits is projected at 75%. This value is an estimate based on similar existing operations in Powertech’s experience profile. Leaching studies were conducted in a lab setting to support this estimate of recovery. Therefore, the overall potential yellowcake production is estimated to be 9.52 million pounds U3O8. Considering the well field development and production schedule, the life of mine, at a production rate of 700,000 pounds per year U3O8 is 14 years.

In principle, in situ recovery from permeable sandstone formations is conducted by injecting a solution (lixiviant) into a mineralized section of the formation and extracting a uranium loaded production composite solution (PC) for treatment in a surface facility to recover the dissolved uranium. Typically, solution treatment produces a barren solution from which a bleed stream is disposed for control of soluble impurities. The remaining solution is reconstituted with reagents, restored with natural ground water to the desired flowrate, and re-injected.

As is the case with nearly all ISR operations, the well fields for the Centennial Project will use oxygen as the oxidant for tetravalent uranium and carbon dioxide as a complexing agent to form water-soluble uranyl dicarbonate, or uranyl tricarbonate. Although the oxygen and carbon dioxide are introduced into the lixiviant as gases, they dissolveunder the static pressure produced by the hydraulic head in the injection well. The targetconcentrations of oxygen and carbon dioxide, respectively, will be 400mg/L and 200mg/L,yielding an anticipated PC concentration of 60mg/L U3O8.