In-situ recovery is a method of extracting uranium from underground deposits without having to dig open-pit or underground mines to physically remove the uranium-bearing ore and other materials.
This method involves injecting a mining solution, called lixiviant, into the ground at specifically targeted depths and locations relative to the ore body. This solution consists of on-site ground water fortified with gaseous oxygen and introduced to the uranium ore body through a pattern of injection wells. The solution dissolves the uranium from the sandstone host.
In order to guard against any migration of mining solution to areas outside the wellfield, the entire wellfield is surrounded by a series of perimeter monitoring wells.
These wells are placed into the aquifer to be mined, as well as into aquifers above and below, to detect any migration of mining solutions outside the ore zone. Prior to mining, baseline water quality parameters are identified for the water within the aquifer to be mined.
During mining operations, the perimeter wells are routinely monitored twice per month for variations in the most mobile baseline parameters that might indicate a migration of mining fluids outside the mining area. Such a detection event is known as an excursion and does not necessarily result in environmental impact. Monitor wells serve as an “early warning” system to allow fine tuning of the injection and extraction flow rates. If monitoring wells detect any of these substances, wellfield operators can alter the injection and extraction rates of nearby wells to draw the fluids back and ensure the mining solutions remain in the designated mining area.
ISR has several advantages over conventional mining methods, including open-pit and underground mining. A primary advantage of ISR over conventional methods is the significantly lower environmental impacts resulting from mining operations, due to minimal surface disturbance and the fact that affected water is restored to pre-mining use standards at the conclusion of operations.