PERTH (miningweekly.com) – Uranium miner Energy Resources of Australia (ERA) produced 566 t of uranium oxide (U₃O₈) during the three months to September, following the progressive restart of its Ranger mine, in the Northern Territory.

Plant operations at the Ranger mine have been suspended since December last year, after a mixture of slurry moved outside the containment area, following the failure of a leach tank.

The miner undertook a progressive restart of the Ranger processing plant in June, after receiving approval from the state and federal governments. While about 46 000 t of ore was milled during the June quarter, no U₃O₈ was drummed or packed for shipment.

Despite the operation’s recent restart, the September quarter production levels were only 7% below those achieved in the previous corresponding period.

ERA told shareholders on Thursday that progress to full mill throughput was achieved during the quarter, and milling rates were higher in the September quarter than in the previous corresponding quarter.

However, the higher milling rates were offset by lower plant recovery, which resulted in the lower production of U₃O₈, compared with the 2013 September quarter. The plant recovery was affected by restrictions on the availability of leach tanks during the period under review.

ERA noted that progressive rehabilitation of the Ranger project area also continued during the quarter, adding that the initial backfill of Pit 3 was now completed.

The infrastructure required to enable the conversion of Pit 3 into a tailings repository was on schedule to be installed by the end of the year.

ERA recently submitted a draft environmental impact statement on its Ranger 3 Deeps underground mine to the Northern Territory Environmental Protection Authority and the commonwealth Department of the Environment.

The project would have a significantly smaller footprint than the previous opencut operation at Ranger, and first production has been targeted for late 2015, pending board and regulatory approval.

ERA noted that the prefeasibility study into the Ranger 3 Deeps underground mine was scheduled for completion by the end of the fourth quarter this year.