To achieve commercial production, Magna completed pre-stripping the mine to give it a 2.9:1 strip ratio, and that number is expected to trend downwards through the mine life. New leach pads were built, and fresh ore is being stacked at a rate of 900 tonnes per hour. The grind size and leach kinetics have been optimized to improve recovery rates to about 70%. The project achieved over 3.5 million person-hours without a lost-time incident.
The pre-feasibility study done last year, estimated the San Francisco mine has measured and indicated resources of 99.7 million tonnes grading 0.45 g/t gold, containing 1.4 million oz., and inferred resources of 11.4 million tonnes at 0.45 g/t gold, containing 171,000 oz.
(This article first appeared in the Canadian Mining Journal)
