The company said production at Huntly had been reducing over the last year with the mine producing only 74,000 tonnes in the period ending December 31.

The company attributed the fall in production to harder mining conditions in some of the extraction blocks.

On November 11 last year, Solid Energy played down concerns of elevated methane levels at Huntly East.

Mining operations were suspended while it was degassed over several days.

At the time, Solid Energy chief operating officer Barry Bragg said there was nothing about the issue to give rise to any concerns despite “alarmist” and “irresponsible” allegations.

“Our monitoring equipment detected elevated gas levels and as a result we implemented our standard procedures for dealing with it,” he said.

The company’s Rotowaro mine also had a disappointing quarter, with production slipping 13% compared to the previous corresponding period to 265,000t.

Overall, Solid Energy mined 1.06 million tonnes of coal in the December 2011 quarter, up 9% year-on-year.

The Christchurch-based company also boosted its coal sales by 15% on the previous corresponding quarter, selling 1.2Mt of product.

Production at Stockton mine was up 15% compared to the December 2010 quarter to 461,000t , with the Stockton coal processing plant contributing 240,000t to the mine’s overall production for the December 2011 quarter.

Spring Creek mine production for the quarter was up 19% year-on-year to 89,000t, though the previous corresponding quarter had been interrupted by two coal heatings underground in November 2010.

The company said its $30 million Huntly North ventilation shaft development was on track to be completed within budget by December 2012.

The shaft will service the northern extension of the Huntly East mine.