LABRADOR — The pilot plant testing ore samples from the Michelin and Jacques Lake uranium deposits, recovered 87.5% of the uranium in the samples using resin-in-pulp (RIP) technology, reports Fronteer Development on behalf of its subsidiary Aurora Energy Resources in Toronto. The tests were performed by SGS Lakefield Research at Lakefield, ON.
Not only is the high recovery rate encouraging, the tests estimate only a modest consumption of energy and consumables for the process. The tailings produced will meet Canadian environmental standards.
The pilot operation included batch grinding, continuous leaching, RIP extraction of uranium, resin elution, and tailings neutralization. The leach-RIP circuit operated at a feed rate of about 2 kg/h and processed approximately 900 kg of mineralization made up from several hundred individual samples. Michelin mineralization was used for the bulk of the campaign, with a 70:30, Michelin:Jacques Lake blend comprising the feed for the final four days of operation.
Overall leach extraction with a 36 hour retention time was 87% with RIP extraction of uranium from the leached slurry averaging 99.7%. Subsequent analysis of the pilot plant data, and additional tests, showed that extraction would likely be 89% if retention times were increased slightly to 48 hours.
When handling Michelin mineralization, sulphuric acid consumption was 28 kg/t. This increased to 34 kg/t when handling the Michelin-Jacques Lake blend and was in keeping with expectations derived from earlier bench scale tests. A mixture of air and sulphur dioxide was successfully used as an oxidant.
Tailings neutralization was performed continuously using ground limestone in the first stage then slaked lime to complete the neutralization reactions. Limestone and lime consumptions were low, at approximately 30 kg/t and 3 kg/t, respectively. The tailings solutions were then treated with barium chloride for radium control.
The Michelin project (including the Michelin, Jacques Lake and several other deposits) lies on land belonging to the Labrador Inuit. They have proposed a three-year moratorium on uranium mining and milling. Aurora maintains close contact with them while continuing exploration work on the project.
Additional information is available at both www.Aurora-Energy.ca and www.FronteerGroup.com.