The company’s metallurgical coal operations continue to perform strongly and it has retained guidance of 47Mt for the 2015 financial year ahead of the wet season and planned longwall moves at the Crinum, Dendrobium and West Cliff underground mines.

Queensland Coal delivered record production and sales volumes with the successful ramp-up of its Caval Ridge mine and record production at Goonyella, Daunia and Poitrel.

Illawarra Coal achieved record production of 4.7Mt in the December 2014 half year as maintenance efficiencies supported higher equipment utilisation rates. The 41% increase from the December 2013 half year also reflects an extended outage at Dendrobium in the prior period.

BHP Billiton CEO Andrew Mackenzie said: “Our operational performance over the last six months has been strong.

“We are reducing costs and improving both operating and capital productivity across the group faster than originally planned. These improvements will help mitigate some of the impact of lower commodity prices and we remain alert to opportunities to further increase free cash flow.”

Energy coal production decreased by 3% in the December 2014 half year to 36Mt and guidance for the 2015 financial year remains unchanged at 73Mt.

“As anticipated, drought conditions constrained production volumes at Cerrejon given the need to manage dust emissions, while Navajo Coal production declined following lower customer demand arising from the closure of three of the five power units at the Four Corners Power Plant,” the company said.

New South Wales Energy Coal production also declined as a result of processing lower yield material during the period and an additional planned wash-plant outage.

At South Africa Energy Coal, higher wash-plant use contributed to a 10% increase from the December 2013 half year, which was affected by industrial action.