RATTLER PROJECT, UTAH, USA
The Rattler Project comprises fifty-one (51) Bureau of Land Management (BLM) unpatented Federal mining claims (encompassing approximately 1,000 acres) located approximately 85km north of Energy Fuels Inc’s White Mesa Uranium/Vanadium mill in Utah – the only operating conventional uranium mill in the USA (see Figure 4).
The project area includes the historical Rattlesnake open pit mine, which was discovered around 1948 and operated through until about 1954. Historic production from the Rattlesnake pit reportedly totalled 285,000 tonnes of ore @ 2,800ppm U3O8 and 10,000ppm V2O5 for 1.6 million pounds of U3O8 and 4.5 million pounds of V2O5.
Figure 4. Location of the Rattler Uranium Project, Utah, USA
HISTORY OF URANIUM EXPLORATION AND DEVELOPMENT IN THE DISTRCIT
The Rattlesnake Deposit was discovered in outcropping rocks of the Jurassic Morrison Formation around 1948.
Extensions of similar mineralisation in adjoining areas were subsequently identified through exploration drilling. The adjacent Pandora, La Sal, Beaver, Energy Queen and Pine Ridge mines, all within 15km of the Rattlesnake mine, operated during the 1970s until the early 1980s, with ore from these mines processed at mills in Uravan, Moab (both now closed) and Blanding (now Energy Fuels’ White Mesa Mill).
Historic production in the immediate district is estimated to comprise around 6.4 million pounds of U3O8 at 3,200ppm U3O8 and 29 million pounds of V2O5 at 14,600ppm V2O5.
Denison Mines and Energy Fuels Inc. reactivated mining at Pandora in 2006, producing a further 412,000 tons of ore between 2006 and 2012 for 1.66 million pounds U3O8 at 2,000ppm U3O8 and 8.4 million pounds of V2O5 at 10,200ppm V2O5.
In 2014 Energy Fuels reported that remaining resources at the Pandora, La Sal, Beaver, Energy Queen and Redd Deposits comprise a total of 1.2Mt at 1,700ppm U3O8 and 8,880ppm V2O5, for 4.5 million pounds U3O8 and 23.4 million pounds of V2O5.
Deposits of the La Sal Trend are sandstone-hosted deposits within the Salt Wash member of the Jurassic Morrison Formation. Deposits are localised in areas of reduced grey sandstone or grey/green mudstone within red, oxidised, hematite-rich rocks of the Morrison Formation. In thin beds of sandstone, mineralisation is tabular, but in more massive sections of sandstone, mineralisation “rolls” across the bedding.
The uranium- and vanadium-bearing minerals occur in fine-grained coatings on the detrital grains; fill pore spaces between sand grains; and replace some carbonaceous and detrital quartz and feldspar grains. The primary uranium mineral is uraninite (pitchblende) with minor amounts of coffinite.
The Rattlesnake deposit is the only outcropping uranium deposit in the immediate area. All other deposits have been discovered with exploration drilling. Mineralisation has reportedly been discovered with exploration drilling immediately down-dip from the Rattlesnake deposit (to the north) – but no drilling information is available. There are reports that some of this mineralisation may have been mined.
If historical drilling data cannot be located, new drilling is warranted, as there is considerable potential to discover additional high-grade mineralisation.