Fronteer Reports 87.5% Uranium Recovery From Auroras Pilot Plant Testing
Aurora Energy Resources, a wholly owned subsidiary of Fronteer Development Group Inc., announce that pilot plant leaching and resin-in-pulp (“RIP”) extraction tests on the Michelin and Jacques Lake uranium deposits in Labrador (the “Michelin Project”) provide strong support for the project’s viability and production potential.
Highlights from the pilot plant and bench scale test work indicate that:
1. The Michelin Project mineralization is predicted to yield an average uranium recovery of 87.5%. 2. The proposed milling process for the Michelin Project is an effective method for treating the Michelin Project mineralization.
3. There will only be a modest consumption of energy and consumables.
4. The tailings test results meet Canadian environmental standards.
These metallurgical test results are from one of several engineering and economic studies Aurora commissioned over the last 18 months and that are now in the final stages of completion. Final data relating to Aurora’s tailings-management options, updated resource estimate, scoping study and economic benefits analysis will be reported in the months ahead.
PILOT PLANT TESTING
To test the metallurgical properties of mineralization from the Michelin and Jacques Lake deposits, Aurora contracted SGS Lakefield Research Limited to operate a continuous, 444-hour (19 day), pilot plant study on Michelin and Jacques Lake mineralization at its Ontario test facility.
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 (SO2) was successfully used as an oxidant.
Tailings neutralization was performed continuously using ground limestone in a 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.
Standard analyses and tests were performed to ensure that the tailings treatment processes could meet strict environmental guidelines. Water fleas (known as daphnia magna) and Rainbow Trout fingerlings were placed in 100% undiluted treated water. As per industry standards, treated tailings water is considered acceptable if more than half the test species in the 100%-undiluted treated water survive over 96 hours. In the Michelin Pilot Plant test, 100% of the fish and water fleas lived over the test period, which indicates the development of a satisfactory treatment process for excess water.
“Given the high uranium recoveries, modest consumption of energy and consumables, and excellent tailings test results in the operation of the pilot plant, we believe the Michelin Project has taken a major step towards demonstrating production viability,” says Bruce Dumville, President and CEO, Aurora Energy Resources.
