In the Slick Rock district, uranium/vanadium deposits of the Morrison are mainly tabular to lenticular and elongate parallel to sedimentary trends. Tabular trends are localized in massive sandstones where clay and mudstone are interstitial, in scattered and streaked gall and pebble accumulations, and are found in discontinuous lenses. Conversely, roll deposits are narrow, elongate, and curve sharply across bedding and appear to be confined to sandstone where clay and mudstone are well indurated within interconnected layers (Figure 8.1a). Mineralization in either case, tabular or roll deposits, averages about 0.25% U3O8 and 1.5% V205 within the impregnated sandstone. The mineralized bodies have an average thickness of 2 ft to 4 ft and range in size from a few feet wide to several hundred feet wide (Fischer and Hilbert, 1952). These deposits can contain a few tons of ore to several thousand tons in the larger ore bodies.

The uranium- and vanadium-bearing minerals occur as fine-grained coatings in detrital grains; they fill pore spaces between the sand grains and replace carbonaceous material and some detrital grains (Weeks et al., 1956).

The primary uranium minerals are uraninite (UO2) with minor amounts of coffinite (USiO4OH). Montroseite (VOOH) is the primary vanadium mineral, along with vanadium clays and hydromica. Metal sulfides occur in trace amounts. Mineralization occurs within tabular to lenticular bodies that are peneconcordant within sedimentar ........

The Slick Rock Project includes the Burro Mine which was owned by Union Carbide Nuclear Corporation (now Umetco Minerals) from 1955 through 1971 producing 404,804 tons and an additional 60,956 tons intermittently up through 1983, based on reported pounds and average grade produced.

The PEA is based on a random room and pillar mining method as was previously employed within the project area and in general through the Colorado Plateau. The characteristics of the Slick Rock mineral deposits are compatible with this method in that mineralization is generally tabular with some moderate rolls, low to moderate dip, and exhibit good rock strength with respect to both roof and floor. The randomness of the room and pillar extraction is due to the variations in uranium grade and thicknesses encountered. Typically, mining will follow the mineralization through underground longhole drilling in advance of mining, face sampling, and mapping concurrent with mining. Pillars are left where the mineralization is weaker in terms of concentration and/or thickness; however, in some cases temporary roof support will be necessary. The nature of the mineralization lends itself to a high extraction rate. The base case assumed 90% mine extraction. The sensitivity analysis evaluated 80% mine extraction.

Specific metallurgical testing is not available for the Slick Rock Project. However, mineralized material from the Slick Rock Project area, as well as similar deposits in the Uravan Mineral Belt has been processed successively for uranium and vanadium for more than 50 years. Further, the PEA is not based on the processing of the mineralized material, but rather the sale of the mineralized material to the White Mesa mill in Blanding, Utah.

On-site processing via vat or heap leaching could produce intermediate products including on-site concentrated product liquor (slurry or paste), or loaded resin, which could be shipped for final processing and drying to existing facilities. This approach would allow shipment of concentrate to a larger variety of existing facilities, whereas, the White Mesa mill is the only mill currently receiving raw mine feed. This approach could include shipment of concentrate to the UEC Hobson facility.