The Inkai project will use the in situ recovery (ISR) mining method. ISR mining produces no waste rock or tailings and results in minimal disturbance to the surface and underground areas mined.
Uranium occurs in sandstone aquifers as coatings on the sand grains at a depth of up to 300 metres.
Uranium is largely insoluble in the native groundwater which is not potable due to naturally high concentrations of radionuclides and dissolved solids. Using a grid of injection and production wells, a mining solution containing an oxidant is circulated through the orebody to dissolve the uranium. The uranium-bearing solution (generally containing less than 1/10 of 1% uranium) is then pumped to a surface processing facility where the uranium is removed using ion exchange resin. The water is re-oxidized and re-injected into the orebody. The uranium is stripped from the resin, precipitated and then dried to form the final product, yellowcake. This process is repeated to remove as much uranium as is economically feasible. When mining at the site is complete, the groundwater will be restored to its original quality.
This is a closed loop recirculation system since the water from the production well is reintroduced in the injection wells. Slightly less water is injected than is pumped to the surface to ensure that fluids are confined to the ore zones intended for extraction. Monitor wells are installed above, below and around the target zones to ensure that mining fluids do not move outside a permitted mining area.
