Production Returns to Normal at Capstone's Minto Copper-Gold Mine, Yukon

Once Root Cause of Throughput Constraints Addressed, Production Ramped up from 2,000tpd to 3,200tpd

VANCOUVER, May 3 /PRNewswire-FirstCall/ - Capstone Mining Corp. (CS: TSX) today announced that production at its Minto copper-gold mine in the Yukon has returned to normal levels following the resolution of issues with the tailings plant. The Minto mill has run at 3,100 to 3,200 tonnes per day ("tpd") through the weekend, with no evidence of sliming in the tailings plant.

"While it was challenging to track down the throughput issues in Minto's tailings plant, the return to full production levels demonstrates the sliming issue has been resolved," said Stephen P. Quin, President & COO of Capstone Mining Corp. "The Minto Mine is now working to maximize production for the remainder of the quarter."

Commencing late February 2010, mill throughput at the Minto Mine was constrained by the capacity of the tailings plant, reducing throughput from around 3,200tpd to an average of just under 2,000tpd for April. Following a systematic evaluation of all possible contributing factors, the root cause of the constraints in the tailings plant was eventually tracked to a partially blocked feed pipe that supplied flocculent (a settling reagent) to the tailings thickener. The blockage was such that it allowed sufficient flocculent to pass through to sustain limited production levels (to no more than 2,000tpd) but, once throughput exceeded those levels, there was insufficient reagent being added to settle the fines, leading to sliming of the thickener. Once the blockage was identified and cleared, operations returned to normal.

Freshet (spring run-off) commenced at Minto during April and is still in process. Based on run-off to date, the total quantity of run-off appears to be significantly less than in 2009 and the new water conveyance network has handled all the run-off water. As part of its water management plan for freshet, some water has been diverted into the open pit in order to maximize available capacity in the water storage pond in case of a future high run-off event. As a result, mining of ore from the pit has temporarily been suspended. However, accelerated mining over the past six months, carried out in anticipation of freshet, has resulted in more than 900,000 tonnes of ore being stockpiled in front of the crusher, sufficient to sustain operations through to the end of the year. Mining will resume once freshet is over.

The TSX does not accept any responsibility for the adequacy or accuracy of this press release.

SOURCE Capstone Mining Corp.