Possible Utilization of Oxygen Scavengers to Enhance Restoration of Insitu Leach Uranium Mining

The Utilization of Insitu Leach (ISL) Uranium Mining has been used successfully to mine Roll-front uranium deposits since it was first tried in the early 1960's tests in Wyoming. Since then, the use of ISL has grown steadily and according to the Uranium Producers of America webpage the method is exceptionally efficient and competitive because it allows production from relatively low grade deposits in the United States (US) and allows it to be competitive with large conventional mines in foreign countries.

The mining process utilizes wells to inject oxygenated lixiviant into the reduced ore body environment which mobilizes the Uranium and allows it to be extracted at the surface for processing. When production terminates, the water quality of the effected aquifer must be restored to original background levels or to levels defined in the regulatory standards. This generally means to return the ore body environment to its original reduced state. To expedite this process, the author suggests the possible injection of Oxygen Scavengers into the restoration (groundwater sweeping) injectate. Other earlier publications on the use of Sodium Sulfide for this purpose have proved promising. We therefore suggest the evaluation of other Sulphur bearing inorganic and other compounds that have been used extensively in the “Oil Field” and for high temperature boiler corrosion control. These would include but not be limited to the following inorganic compounds:

· Sodium Sulfite

· Sodium Bisulfite

· Ammonium Bisulfite

· Sulphur Dioxide and

· Hydrazine

The Oxygen Scavenger chemistry of these compounds are presented as well suggesting other possible organic compounds and bacteria that may produce a reducing environment.