JOHANNESBURG (miningweekly.com) – While dual-listed Glencore’s copper and nickel production fell in the third quarter, the diversified miner said on Monday that this would not impact full year earnings.

Copper production of 946 500 t for the quarter ended September 30 was 11% lower than the comparable quarter in 2016, owing to the sale of an $880-million stake of its Ernest Henry gold and copper mine in Queensland, Australia in August last year.

Output was also hit by smelter maintenance at Mount Isa in Australia, reduced throughput at the Mutanda mine in the Democratic Republic of the Congo, owing to power interruption at Mopani, end-of-mine-life production declines at the Alumbrera mine, in Argentina, and the timing of lower copper grades at the company’s Antapaccay operations, in Peru.

Nickel production fell 2% to 80 700 t as a result of maintenance at the Sudbury Integrated Nickel Operations (INO) and the Murin operations, in Australia, compounded by a higher proportion of third-party feeds in INO's metallurgical mix.

“Own-sourced zinc production of 827 400 t was 5% up on the comparable period, mainly reflecting the transition to higher zinc grade areas at Antamina,” the company said in its quarterly production report.

African zinc assets produced 92 100 t of zinc and 3 700 t of lead to August 31, before they were sold to Trevali Mining.

Coal production of 91-million tonnes was in line with the comparable period, as expected increases from productivity improvements and Glencore's higher equity share in certain mines were offset by the impacts of industrial action in New South Wales and unusually heavy rainfall in Colombia.

Glencore’s oil entitlement production interest of 3.9-million barrels was 36% below the comparable quarter in 2016, reflecting natural field declines, having only recommenced drilling in Chad in the second half of 2017.

“The trend in Chad is expected to improve as the results from the single-rig drilling campaign start to be realised,” said the company.

Cobalt production of 17 200 t was within 5% of the comparable period, while attributable ferrochrome production of 1.107-million tonnes was in line with the comparable period.