While total production uncharacteristically fell across its products of thermal coal, semi-soft coking coal and hard coking coal last year, Rio noted the performance stacked up well against its production guidance for the year.

In this regard Rio said its share of Australian thermal coal output of 19.1 million tonnes was 6% above guidance, semi-soft output was 7% above the 3Mt guidance and hard coking coal production of 7Mt was in line with the target.

In the case of thermal coal, Rio said said significant production gains were made with production records clocked up at the Hail Creek mine in Queensland and the Hunter Valley Operations and Bengalla mines in New South Wales.

When excluding the giant Clermont thermal coal mine in Queensland Rio sold to Glencore for $US1.02 billion ($A1.25 billion) in June 2014, Rio said thermal coal production increased by 15% compared to 2013.

Without this adjustment Rio’s total thermal coal output, which included some production from the Benga mine in Mozambique it completed selling to an Indian consortium in October 2014, was down nearly 5% compared to 2013.

The Benga mine also produced coking coal, with Rio’s total coking coal output falling 9% year-on-year to 7.47Mt in 2014.

Rio’s share of semi-soft output fell nearly 17% to 3.2Mt last year.

On the fall of hard coking coal output, Rio said it was due to the Kestrel longwall mine ramping up at its new southern extension and to the Hail Creek mine priortising thermal coal output from a processing plant by-product stream to “deliver increased margins in the current price environment”.

“In a challenging market, Rio Tinto remains focused on operating and commercial excellence to leverage our low-cost position and maximise value for shareholders.” Rio CEO Sam Walsh said of the production results.

Rio will announce its full-year financial results next month and it had promised bigger shareholder returns.