The mine, near Greymouth on the South island, moved into full production only four months ago, but is failing to meet full production targets. Annual production is estimated to be up to 800,000 tonnes. In September the mine was forced to evacuate after gas readings went too high.

Spring Creek uses a high-pressure hydraulic monitor at the coal face, similar to methods used at the company’s Strongman 2 mine, which closed in August 2003. Solid Energy said the monitor has been achieving target extraction rates, but development work was slower than forecast due mainly to difficult geology.

Solid Energy chief operating officer Barry Bragg said that the company has stopped extraction at the mine to undertake a complete review of the development and mining systems and practices.

The 103 miners have been diverted to further mine development rather than production.

“One of the most immediate actions that we need to undertake is to bring forward recruitment plans at Spring Creek as we urgently need more development shifts working at the mine. We estimate that we will need up to 50 more staff at Spring Creek over the next 12 to 18 months,” Bragg said.

“The future for the mine is very positive, but we need to ensure that we get development rates up to secure long-term monitor extraction.”