Wyoming offers a number of advantages for uranium exploration, including a long history of uranium production and exploration, very favorable geology for both economical extraction and environmental safety, a pro-mining sentiment and excellent infrastructure. Wyoming also contains the nation's largest known uranium reserves. As the price of uranium has climbed in recent years, particularly since 2006, so has the interest in Wyoming exploration. Dozens of companies have descended on the state, staking new claims, re-working old claims and looking to reestablish mines that closed during the previous downturn in uranium prices. Although uranium was first produced in Wyoming in 1920, the boom years came in the late 1970s and early 80s. Production fell off sharply, however, as uranium prices plummeted to below $10 per pound in the early 1990s. Most of the 4.1 million pounds produced in the United States in 2006 came from Wyoming.
A key advantage to Wyoming uranium mining is that the state's geology allows for in-situ uranium extraction. In-situ extraction provides relatively inexpensive recovery with minimal environmental impact.
In-Situ Recovery of Uranium
In situ recovery (ISR), also known as solution mining, leaves uranium ore where it is, in the ground, and recovers the minerals by dissolving them and pumping the pregnant solution to the surface. There the minerals can be recovered from the solution. There is little surface disturbance and no tailings or waste rock generated. However, the orebody needs to be permeable to the liquids used and located so they do not contaminate ground water away from the orebody.
Before recovery begins, well pump tests are performed to define the hydrological characteristics of the ore zone and obtain information about the ground water flow. This process also determines if the surrounding strata are impermeable enough to prevent movement of the recovery solution into underlying or overlying aquifers. Aquifer water samples are taken throughout the process to document water quality.