Discovery Metals says it realised a record metal production of 1,713 tonnes of contained copper and 75,348 oz of contained silver and high material movement of 3.24 Mt from the two operating open pits during May. In the same period, 168 Kt ore was processed at average head grade of 1.21% Cu and 15.3 g/t Ag included Zeta high grade ore, Zeta low grade ore and Plutus transitional ore. The overall copper recovery of 84% and silver recovery of 91% and the company said production outcomes in line with the plan for the month.
Mining
Mining production (waste plus ore) for May 2013 was 3.24 Mt. “This is the largest material movement for any month to date and is the fourth consecutive improvement in production since January 2013.
At the end of May blasted stocks (Ore + Waste) of 1.1 million tonnes were available for mining in the two open pits.”
Mining during May was undertaken in both the Zeta and Plutus Open Pits. The company noted that the strategy adopted at the end of 2012, to accelerate the establishment of the first stage of the Plutus Open Pit, has now positioned the operation with two sources of ore and improved operational flexibility.
Within the Zeta Open Pit both sulphide ore and low-grade material were mined during the month. Within the Plutus Open Pit only oxide and transitional ores have been exposed to date and first sulphide ores are planned for mining in June.
“With ore exposed in both Open Pits, continued excavation at the design rate of approximately 3.1 Mt per month will deliver increasing quantities of ore to the concentrator over the next 3 months and continue the production ramp up. Current scheduling fills the concentrator (to design capacity) with ore for the first complete month in July,” Discovery said.
Concentrator
During May, 168 kt of ore was processed containing 1.21% Cu and 15.3% Ag. The total mill throughput consisted of Zeta sulphide ore: 136.6kt @ 1.35% copper and 17 g/t, Zeta low grade material 19.4kt @ 0.4% copper and 5 g/t Ag and Plutus transitional ore 11.7kt @ 0.93% copper and 12 g/t Ag.
The mill has previously demonstrated the ability to process ore at rates in excess of the 3 Mtpa nameplate. With the planned ore delivery in May not requiring full mill utilisation, the mill has been operated at conservative throughput rates during the days it operated in May.
Average metallurgical recoveries of 84% of copper and 91% of silver were achieved for the month. Overall copper recovery is in line with expectations and silver recovery continues to outperform the original estimates.
Metal production
Concentrate production in May was 4,112 tonnes at 41.7% copper and 570g/t silver containing 1,713 tonnes of copper and 75,348 ounces of silver. “This was the highest monthly metal production figure from the Boseto Copper Project to date and was in line with the plan for the month.”
