Pike River re-entry plan approved by NZ government

The families of the miners killed in the Pike River coal mine explosions have been informed this morning on the NZ Government's plan to re-enter the mine.

The plan was reformatted last week, after initially being put together in early August.

The government has now approved this re-jigged plan, and conditional funding for the staged re-entry of the mine, NZ energy and resources minister Simon Bridges has announced.

It will see recovery teams enter and explore the main tunnel up to the rock fall.

It follows the approval in principle of the mine entry risk assessment by Solid Energy.

An additional risk assessment will be undertaken at the end of each stage before proceeding to the next stage.

Stage one will see workers plug the top 50 to 60 metres of the 100 metre deep ventilation shaft with around 700 cubic metres of concrete to allow for full control of the mine's atmosphere.

Stage two consists of drilling new boreholes into the top of the main tunnel, inserting cameras to check tunnels where a second plug could be placed and then put expanding foam via borehole into the tunnel.

This will form a plug around 2.3 km into the mine and 40 metres on the portal side of the rock fall.

After this recovery teams will pump nitrogen into the tunnel between the plug and the rock fall to prevent fresh air for entering the closed off sections of the mine, which reduces the risk of fires re-igniting within the tunnels.

Once ventilation is complete stage three will see the teams finally enter the mine.

Work is scheduled to begin in October,nearly three years after the initial explosions.

Bridges stated that "our criteria are that any re-entry into the tunnel up to the rock fall is safe, technically feasible and financially credible".

"Safety is paramount, and the High Hazards Unit of the Ministry of Business, Innovation and Employment has reviewed the plan and is comfortable with it. 

"This is a highly complex and technical operation and it will be carefully managed in stages, with a risk assessment undertaken at each stage. Ensuring the safety of workers is an absolute bottom line for the Government and Solid Energy."

The cost of the plan has been estimated ataround NZD $7.2 million.


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