Last Wednesday inspectors from the Department of Labour’s High Hazards Unit issued the prohibition notice on both preparing underground resource blocks for mining and extraction but allowed other underground duties to continue.

The inspectors identified an accumulation of methane in a recently mined area of the underground mine. They asked for more information about the accumulation of methane and how the company is managing the methane.

The first notice was withdrawn on Friday and replaced with one on extraction only.

“The Huntly East workforce has been operating underground continually and Solid Energy remains confident the mine is operating safely,” the company said.

“The mine’s stockpiled inventory ensured no customers were affected by the short suspension in coal extraction.”

The establishment of the HHU was announced last August, following recommendations from an independent review of the Department of Labour’s interactions with Pike River.

The HHU is now running at full strength with roles for all six specialist health and safety inspectors filled. The NZ government says it hopes the HHU will prevent a tragedy on the scale of the Pike River accident, where 29 miners lost their lives.

"Mining is a hazardous activity and we are doing all we can to make sure mining in New Zealand is as safe as possible," Labour minister Kate Wilkinson said.

"We have a lot to learn from the Pike River tragedy. The department is working with Australian mining regulators.”