Consolidated metal production from triple-listed Sierra Metals decreased 3% during the second quarter of the year, the base metals miner said Monday. Sierra, a Canada-based growing polymetallic mining company, attributed the decrease to lower throughput, lower head grades and lower recoveries of all metals – except gold recoveries at Bolivar copper mine, in Mexico – as well as lower throughput, lead and zinc head grades, and silver and lead recoveries at Cusi silver mine, in Mexico.
