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URANIUM EXPLORATION AND MINING ON THE BUREAU OF LAND MANAGEMENT IN ARIZONA
Colorado Plateau Uranium Deposits of Arizona • Favorable environments for the occurrence of uranium minerals on the Colorado Plateau within Arizona are mainly: • Sandstone type uranium deposits, and Breccia pipe type uranium deposits. • Recently the importance of breccia pipe deposits has far exceeded that of sandstone type deposits.
Sandstone Type Uranium Deposits • Occur in the Upper Jurassic Morrison Formation and the Upper Triassic Chinle Formation. • These deposits typically occur in sandstones and conglomerates deposited along ancient stream channels. • Uranium mineralization is often associated with carbonaceous material contained within the sandstone and conglomerates.
Breccia Pipe Uranium Deposits • Are unique geologic features on this portion of the Colorado Plateau created by solution and collapse. • The formation of breccia pipes began with karst development in the Mississippian Redwall Limestone. • Structural readjustments caused upward propagation of the fractures and faults localized in the Redwall caves, which resulted in the stoping of successively younger units, vertically thousands of feet. • The stoping processes, which involved both chemical dissolution and mechanical failure of roof and wall rock, produced a column of brecciated rock within the steep walls of the pipes.
Breccia Pipe Mineralization • Mineralization within breccia pipes has resulted in the formation of uranium, copper, germanium and gallium deposits of economic importance. • All mineralization of economic importance appear to be between the Coconino Sandstone and the Supai Group. • Mineralization occurs either as discontinuous vertical pods in breccia within the pipe or in annular rings along the outside edge of the pipe. • Uraninite is the primary uranium mineral and occurs in the matrix and, to a lesser degree, in clasts within breccia. It occurs in association with copper, arsenic, nickel, lead, zinc and silver.
Lake Havasu Field Office • Universal Uranium: Targeted uranium in sediments of the Artillery Peak Fm. Exploration consisted of 41 core holes on 3 sections. • Twenty-six of the drill holes twinned previous holes to confirm the potential for 1. 7 million lbs of U 3 O 8 with an average grade of 0. 113%. • Universal has since abandoned their interest in the property. • Uranium King: Exploration proposal for 13 core holes on 4 sections drilling to commence in fall/winter. • Approximately 500 new mining claims for uranium have been staked in the past few years.
Arizona Strip District Office
Breccia Pipe Exploration • Approximately 1000 breccia pipes and collapse features are identified on the Arizona Strip. • Only a small percent of breccia pipes are mineralized and of those only a small percent have economic potential. • Exploration includes geochemistry, geophysics, radiometrics, aerial photo / Landsat interpretation, and mapping.
Exploration Notices and Plans • Since April 2004 more than 8, 000 new mining claims have been located on the Arizona Strip for uranium. • Since September 2005, the Arizona Strip Field Office has received 72 Notices and one Plan for uranium exploration. • Approximately 300 exploratory drill holes have been proposed, of which about 250 holes have been drilled.
Drilling for Breccia Pipes • Once the target is located the presence of the breccia pipe is confirmed by drilling. • Shallow stratigraphic holes are usually drilled first to confirm the geometry of the throat. • Deep diamond core holes are then drilled to define the ore body and estimate resources and reserves. • During the 70’s and 80’s more than 1, 200 holes were drilled on the Arizona Strip exploring for breccia pipes.
Breccia Pipe Exploration 0 Depth (feet) 500 1000 1500 2000 Surface geological mapping and imagery defines a target Shallow drilling locates the pipe throat Deep drilling defines the orebody
Arizona Strip Breccia Pipe Mines • In the 70’s through the early 90’s extensive uranium exploration resulted in the discovery of numerous pipes. • Energy Fuels Nuclear (EFN) developed six uranium mines from eight breccia pipes during the 80’s and 90’s. • EFN's production from these mines totaled 1. 472 million tons of ore with an average grade of 0. 65% U 3 O 8 containing 19. 04 million pounds of U 3 O 8. Hermit Kanab N. Pigeon Hermit
Uranium Production from Breccia Pipes on the Arizona Strip • Of the six mines three were closed and have been reclaimed (Hack Mine Complex Pigeon Mine and Hermit Mine). • The other three (Kanab North Mine, Arizona 1 Mine and Pinenut Mine) were shut down and put on “care and maintenance”. • These mines are now owned by Denison Mine (USA) Inc. , (Denison).
Proven Reserves from Breccia Pipes on the Arizona Strip • Denison has announced they intend to re-open the Arizona 1 mine during 2008 and then re-open the Pinenut mine and evaluate Kanab North. • The proven reserves in the Arizona 1, Pinenut and Kanab North mines are estimated to be 190, 000 tons of ore with an average grade of 0. 522% U 3 O 8 containing 1. 98 million pounds of U 3 O 8.
Proposed New Mine Development on the Arizona Strip • Denison visited the Arizona Strip Field Office to discuss the development of a new mining operation. • The new mine includes the EZ-1, EZ-2 and WHAT pipes and would entail sinking a single shaft and drifting horizontally into the three deposits.
Why the Arizona Strip • Exploration quick and economical • High grades and small mines – Typical ore grade ± 0. 60% U 3 O 8 – Relatively short development time – Small footprint (mine complex is < 20 acres) – Easy reclamation ( waste put back in mine ) – Ore body is more than 1000 ft. above regional aquifer.
Issues Affecting Mining on the Arizona Strip • June 25, 2008, The House Natural Resources Committee adopted a resolution to require the Secretary of Interior to withdraw more than 1 million acres of public lands adjacent to the Grand Canyon National Park from the operation of the mining law, subject to valid existing rights.