TORONTO (miningweekly.com) – Canadian silver producer Primero Mining’s mineral reserves have been negatively impacted after it increased the minimum cutoff grades at its two active mines in Canada and Mexico.
TSX- and NYSE-listed Primero's 2014 year-end gold reserves declined by 9% from 2013 to 1.9-million ounces of gold. This was mainly owing to the application of higher cutoff grades at the Black Fox mine, in Ontario, Canada, and San Dimas, in Durango state, Mexico, and the impact of fewer expected ounces from the Black Fox openpit, as a result of lower-than-expected grades.
The company on Wednesday noted that it was focused on delivering high-quality, high-margin underground ounces, which had resulted in a 4% increase to 5.7 g/t in the gold reserve grade at its platform San Dimas mine, as well as a 19% increase in the underground gold reserve grade to 7.5 g/t at Black Fox, located near the Timmins gold district.
While the compliant resources remained relatively flat, Primero had increased the 2014 year-end gold and silver measured and indicated resources by 1% and 4%, respectively, over 2013 to include 3.2-million ounces of gold and 82.5-million ounces of silver.
The company's 2014 exploration efforts paid off, when a new high-grade vein was discovered at San Dimas. Channel samples of the Jessica vein in the Central block averaged 10.4 g/t gold and 1 606 g/t silver over 1.4 m, along 98 m of exposed vein.
Primero also further defined the San Dimas’ Victoria vein, revealing that it was, in fact, two narrower veins. Recent intercepts included 49.7 g/t gold and 270 g/t silver over 1.1 m.