JOHANNESBURG (miningweekly.com) – 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.

This was partially offset by higher throughput, higher copper and zinc head grades, and higher recoveries of all metals, except gold, at Yauricocha polymetallic mine, in Peru.

"Sierra Metals continues to see solid metals production and tonnage processed at our flagship Yauricocha mine. We are working to increase tonnage at Bolivar with the procurement of new equipment and through the exploration and development of higher-grade ore sources, which are expected to come into the mine plan early next year," said Sierra president and CEO Igor Gonzales.

The company reported a 3% decrease in both silver equivalent production to 2.7-million ounces and copper equivalent production to 23.1-million pounds during the second quarter.

Total tonnes processed decreased 10% to 454 805 t.

Yauricocha achieved a 14% increase in silver equivalent production and 10% increase in throughput during the second quarter under review.

“At Cusi, weaker production was the result of a new plan, which refocuses efforts away from narrow veins and emphasises the access, development and production from the Santa Rosa de Lima zone, which has wider structures as well as higher silver grades,” commented Gonzales.

Sierra continued work at all its mines to improve grade, operations and best practices, as well as introduce modern equipment.

“Management is optimistic that these changes will serve to increase production and improve grade for the latter part of 2017 and for the years to come,” he concluded.