Plant brings mine reentry closer
REENTRY into the Pike River Mine moved a step closer with the crucial installation of a nitrogenproducing plant to remove the dangerous levels of methane from the closedoff mine shaft.
Pike River Recovery Agency reentry chief operating officer Dinghy Pattinson said the hired plant was briefly run this week to pump nitrogen through pipes at the mine portal, before bad weather prompted its shutdown.
‘‘We’ll be running the plant every weekday through to our Christmas closedown,’’ he said in a statement.
Last month was the eighth anniversary since 29 men died in a mine explosion on November 19, 2010.
The plant is important to reentry as the Pike River Mine workings and main access drift tunnel are full of methane, which is dangerous when mixed with fresh air, and the nitrogen will displace it.
Mr Pattison said the plan was to conduct a safe manned reentry based on filling the tunnel with fresh air, so people going into the drift could breathe normally without breathing apparatus.
In order to purge the methane gas, two 4.5km polythene pipelines are being laid up the hill above the portal, so nitrogen can be pumped into boreholes at the top end of the mine.
Three new boreholes will be drilled in the new year, two to assist getting the nitrogen in and the third to monitor gases in the mine.
The intention is to flush the methane from the mine using nitrogen injection from the portal seal and the methane will be discharged from the mine through boreholes.