Coeur Mining, Inc has announced the achievement of several critical milestones at its major Rochester expansion project in Nevada, including the production of the first silver and gold ounces. Following a ramp-up period expected to last into early 2024, Rochester is expected to drive a step-change in the company’s overall production levels, cost profile, and cash flow.
Metal production from the new Stage VI leach pad and Merill-Crowe process plant leach began mid-month with initial doré poured September 19. Approximately one-third of the eight million tons of ore on the new pad are currently under leach. The Merrill-Crowe plant is achieving a flow rate of roughly 3,500 gallons per minute of solution. Full ramp-up to commercial production of around 13,000 gpm is expected to be achieved in early 2024.
With the primary gyratory crusher now installed, construction of the new three-stage crushing circuit is now substantially complete. Once fully ramped-up, throughput is expected to average 32 Mt/y, which is approximately 2.5x higher than historical levels, making Rochester one of the world’s largest open pit heap leach operations.
A multi-day test of truck and loading capacity was completed earlier this month to ensure that the mine can support the higher throughput rates associated with the newly-configured Rochester circuit. This test confirmed the mine’s ability to safely support the designed capacity of up to 100,000 t/d in 2023 and up to 132,000 t/d in 2024. Data gathered during the test will be used to refine processes and identify opportunities for additional efficiencies in cycle and load counts.
“The achievement of these three critical milestones marks the beginning of a new growth phase for Coeur,” said Mitchell J. Krebs, President and Chief Executive Officer. “The focus is now shifting to commissioning, ramp-up, and mine optimisation initiatives as well as prioritising several adjacent exploration targets located on Rochester’s prospective 69-square mile land package. Coeur’s project team has overcome numerous challenges over the last three years to arrive at this key inflection point and deserves thanks for their resilience and commitment.”