In-situ Leach - Uranium

Uranium

Solutions used to dissolve uranium ore are either acid (sulfuric acid or less commonly nitric acid) or carbonate (sodium bicarbonate, ammonium carbonate, or dissolved carbon dioxide). Dissolved oxygen is sometimes added to the water to mobilize the uranium. ISL of uranium ores started in the United States and the Soviet Union in the early 1960s. The first uranium ISL in the US was in the Shirley Basin in the state of Wyoming, which operated from 1961-1970 using sulfuric acid. Since 1970, all commercial-scale ISL mines in the US have used carbonate solutions.

In-situ recovery involves the extraction of uranium-bearing water (grading as low as .05% U₃O₈). The extracted uranium solution is then filtered through resin beads. Through an ion exchange process, the resin beads attract uranium from the solution. Uranium loaded resins are then transported to a processing plant, where U₃O₈ is separated from the resin beads and yellowcake is produced. The resin beads can then be returned to the ion exchange facility where they are reused.

At the end of 2008 there were four in-situ leaching uranium mines operating in the United States, operated by Cameco, Mestena and Uranium Resources, Inc., all using sodium bicarbonate. ISL produces 90% of the uranium mined in the US. In 2010, Uranium Energy Corporation began in-situ leach operations at their Palangana project in Duval County, Texas. In July 2012 Cameco delayed development of their Kintyre project, due to challenging project economics based on $45.00 U₃O₈. One ISR reclamation project was also in operation as of 2009.

Significant ISL mines are operating in Kazakhstan and Australia. The Beverley uranium mine in Australia uses in-situ leaching. ISL mining accounted for 41% of the world's uranium production in 2010.

Examples of in-situ uranium mines include:

• The Beverley Uranium Mine, South Australia, is an operating ISL uranium mine and Australia's first such mine.
• The Honeymoon Uranium Mine, South Australia, due 2008, will be Australia's second ISL uranium mine.
• Crow Butte (operating), Smith Ranch-Highland (operating), Christensen Ranch (reclamation), Irigaray (reclamation), Churchrock (proposed), Crownpoint (proposed), Alta Mesa (operating), Hobson (standby), La Palangana (operating), Kingsville Dome (operating), Rosita (standby) and Vasquez (restoration) are ISL uranium operations in the United States.
• In 2010 Uranium Energy Corp. began an ISL mining operation in the Palangana deposit in Duval County, Texas. The ion exchange facility at Palangana trucks uranium loaded resin beads to the company's Hobson processing plant, where yellowcake is produced. Uranium Energy Corp. has three additional South Texas deposits permitted or in development.

See Uranium mining in the United States