A tough market for coal miners has led to Whitehaven Coal reporting an $11.6 million half year loss.

The result in the six months to December 31 was an improvement on the $48.6 million loss the NSW-based miner posted in the prior corresponding period.

Whitehaven sold and produced more coal during the period, lifting revenue by 43 per cent to $402.2 million.

But operating expenses, selling and distribution expenses and higher depreciation and amortisation costs were still high enough to prevent a profit.

Whitehaven’s net debt also jumped to $557 million, from $472 million a year ago, as it develops its flagship Maules Creek project and expands the Werris Creek mine.

Managing director Paul Flynn said the result featured a big turnaround in cash from operations and a disciplined approach to capital investment.

Production costs declined by 10 per cent to $71.69 a tonne, at a time when prices were weak compared to recent years, but flat on a year ago.

“We are delighted to have achieved a wide range of very positive financial, strategic and operational outcomes during the half,” Mr Flynn said.

“While not ignoring future potential for fluctuations in the coal price, we remain of the view that underlying demand continues to trend upwards for Australian coal and, in particular, for the higher grades of metallurgical and thermal coal where we are increasing capacity.”

No dividend was declared.

Whitehaven shares gained 6.5 cents, or 3.8 per cent, to $1.775.