Kvanefjeld uranium project

The purpose of the Kvanefjeld uranium project is to evaluate the possibility of a uranium production from the deposit at Narssaq, South Greenland. The project comprises investigations in the fields of geology, mining, process chemistry and technology, economy and environment protection. The predominant uraniferous rock is a nepheline syenite called lujavrite in which the main uranium mineral is steenstrupine. The deposit can be mined in an open pit. Calculations have shown a resource of 56 million tonnes of ore with an average grade of 365 ppm corresponding to 20,400 tonnes of uranium. The uranium is extracted by a sodium carbonate solution at 260degC in an autoclave. A pilot plant has been established including ball mill, continuous pipe autoclave and a belt filter for separation of leach liquor and residue. The uranium is finally precipitated as UO2 by reduction in an autoclave at 260degC. With the existing ore sample, recoveries of more than 80% have been obtained. The carbonate leaching causes a low solubility of most contaminants in the tailings. A draft project has been prepared for an industrial plant in Greenland. The total investments have been calculated at 3 x 109 Dkr. Electrical energy is assumed to be supplied by a hydropower plant at Johan Dahl Land. The mine and mill are expected to employ 500-600 persons. (author)