In its first quarter earnings statement, Hudbay Minerals announced that its Constancia mine in Peru achieved commercial production on April 30. Ocean shipments of copper concentrate from Constancia began the same month, and the mine and concentrator are currently operating at or above design capacity.
“Reaching commercial production on schedule at the Constancia mine is a major milestone for Hudbay,” said David Garofalo, president and CEO. “This achievement strengthens our position as a low-cost, high-quality copper and zinc producer. Constancia has allowed us to broaden our skills as a mine developer.”
The ramp-up has met expectations with regards to throughput, recovery and product quality. The plant is performing as designed, and throughput has occasionally exceeded design capacity due to favorable ore characteristics, with peaks of more than 90,000 metric tons per day (mt/d).
Copper recovery in April averaged just over 65%, which is in line with ramp-up design and expectations. Concentrate grade has averaged 27% copper year-to-date with average concentrations of deleterious elements below penalty levels. As of April 30, 42,575 mt of copper concentrate had been produced, of which approximately 20,500 mt had been shipped.
The focus in the initial stages of ramp-up was on ore throughput with an aim to meet saleable concentrate specifications. The focus is currently on increasing copper recovery while maintaining throughput and concentrate quality. A key component of improving copper recovery is expected to be the recently started concentrate regrind circuit.
Hudbay continues to expect the operation to achieve steady state design and feasibility level recoveries of copper in the fourth quarter of 2015. In addition, assuming that the copper ramp-up continues as planned, the company intends, in the second quarter of 2015, to begin to ramp up the molybdenum concentrate separation circuit, which has achieved mechanical completion.
Mining fleet performance is approaching design expectations; a mine dispatch system has been installed and is providing the necessary data to further optimize the fleet. To date, mine reconciliations have indicated that the long-term model is supported by field measurements. Although it is too early to evaluate mine reconciliation metrics, management is confident that grade and geology characteristics are well represented in the long-term plan.
Sustaining capital expenditures are ongoing as planned; the tailings management facility and the water harvesting and management are in scope and on schedule.
Hudbay has received approval of a second modification to the environmental and social impact assessment (ESIA) for Constancia. The ESIA modification recognizes the current infrastructure and incorporates the mining of the Pampacancha deposit. Hudbay expects to begin negotiations for the purchase of surface rights to the Pampacancha deposit later this year.