Talvivaara Mining Co., which recovers nickel, zinc and copper from bio heap leach process solutions at its operations in eastern Finland, has announced plans to recover small amounts of uranium that also leach out of its ores. Uranium grade in the Talvivaara ore averages 15 to 20 ppm, and uranium concentration in the heap leach solutions is low, at about 25 mg/l. However, Talvivaara reports that it has developed a solvent extraction process that can economically extract about 350 mt/y of U3O8 from these solutions. In the company’s current production process, extremely small concentrations of uranium are deposited in an engineered gypsum pond intended for process precipitations.
Talvivaara has drawn up tentative process plans in cooperation with Outotec and Norilsk Nickel Harjavalta. The planned process modification will not alter discharge levels or other environmental impacts of the operations, as defined in Talvivaara’s current environmental permit. Talvivaara is currently preparing necessary documentation for permit applications and is continuing its investigations relating to the utilization of uranium.
Investment in the solvent extraction plant is estimated at about €30 million. Annual production costs are estimated at €2 million. The extraction plant is expected to employ around 20 people directly and some 50 people indirectly. Talvivaara is in discussions with companies in the industry regarding potential cooperation on the project, after which a final financing and operating model will be determined.
The U3O8 produced at Talvivaara will be packaged in airtight steel containers and shipped abroad for further processing.
The Talvivaara mine came into production in late 2008, with initial design capacity of 33,000 mt/y of nickel, plus byproduct production of 60,000 mt/y of zinc, 10,000 mt/y of copper, and 1,200 mt/y of cobalt. During the first half of 2009, the company decided to expand capacity to 50,000 mt/y of nickel by 2012, with ore production increasing from 15 million mt/y to 22 million mt/y.