PERTH (miningweekly.com) – Copper miner Oz Minerals on Tuesday reported its highest quarterly output since 2010, as the miner prioritised higher-value copper feed at its Prominent Hill mill, in South Australia.

Copper production for the three months to June 30 reached 32 991 t, compared with the 31 160 t delivered in the previous quarter, while gold production declined from the 32 874 oz reported in the March quarter to 24 790 oz.

For the half-year ended June, copper production reached 64 151 t, while 57 664 oz of gold was produced.

Oz reported on Tuesday that the Malu openpit mine continued as planned during the quarter under review, with some 2.5-million tonnes of ore mined during the quarter, consisting of two-million tonnes of copper/gold ore and 500 000 t of gold-only ore.

The Ankata underground mine maintained a consistent performance, with some 254 836 t of ore mined during the quarter, at an average copper grade of 1.86%.

“While the Malu openpit is expected to reach the end of its mine life in 2018, it will continue to generate revenue for a further four years. The value will be realised from the run-of-mine stockpiles until 2022. This will be further supplemented by the underground operations,” said Oz Minerals CEO and MD Andrew Cole.

He noted that, at the end of 2018, Oz Minerals' copper ore stockpiles would have between 30 000 t and 40 000 t of copper contained metal and a further 45 000 oz to 50 000 oz of gold. Gold ore stockpiles were expected to be between 450 000 oz and 500 000 oz of contained gold.

Some 30 275 t of copper and 29 650 oz of gold was shipped during the quarter under review, along with 164 468 oz of silver.

C1 cash costs for the quarter reached $0.75/lb, which was higher than the $0.63/lb reported in the previous quarter, owing to the lower gold production and lower inventory credits as milling rates increased.

For the six months to June, C1 cash costs reached $0.69/lb, which was below the yearly guidance range.

In April this year, Oz announced a new growth strategy, which was aimed at cutting fat and focusing on acquiring value accretive assets. Cole said on Tuesday that the quarterly results indicated the beginning of Oz Minerals delivering on that strategy.

“A renewed sense of focus across the company has seen costs tightly managed, production of copper up and new revenue generating opportunities, such as Malu underground commissioned three months early.”

Cole noted that while the current performance of the existing operations was encouraging at the early stage of the new strategy, several of the third-party assets that have been reviewed for potential acquisition did not meet the company’s strict investment criteria.

“We continue to undertake due diligence on several other potential assets,” Cole said.