Re-entry and exploration of the main tunnel of the former Pike River Mine will be subject to on-going assessment of the safety and technical feasibility as each stage of the process is undertaken, says Solid Energy Chairman, Mark Ford.
The Government announced today that it had approved conditional funding of a staged plan to re-enter and explore the tunnel up to a rockfall approximately 2.3 km in from the mine portal.
This follows Solid Energy Board approval in principle for the overall approach that had been developed to re-enter and explore the tunnel and for the first stage of the project, sealing the mine’s ventilation shaft which is necessary to stabilise the atmosphere in the tunnel. Progressive approvals by the Solid Energy Board and on-going monitoring will be required for all stages of the project.
“We have to be satisfied that the mine atmosphere can be effectively managed before we let anyone back into the tunnel. The Solid Energy board will need to be confident that all stages of the plan can be done safely and we won’t know that until the ventilation shaft has been plugged,” Mr Ford says.
“This is a complex initiative which will require constant and formal monitoring and review. As we will be working with uncertain outcomes at every step of the way, any major variations from the original plans will have to be re-assessed as to their relative safety and any major variations will also need to come back to the Solid Energy board for further evaluations of the risks and their acceptability.
Mr Ford said Solid Energy gave an undertaking, when it bought the assets of the former Pike River Coal company, that it would do its best to develop a safe plan to explore the main tunnel. “The emphasis for us has always been on that word ‘safe’,” he said.
The conceptual project plans for the tunnel re-entry have been developed by a group of mining experts, including Solid Energy staff, independent mining consultants, New Zealand Mines Rescue Service, with oversight from the Ministry of Business, Innovation and Employment’s High Hazards Unit. An independent panel of experts (mining engineers, ventilation experts, risk management experts) has formally assessed the risks of the plans. The expert panel has experience in mine recovery and work of this complexity and risk. MBIE Mines Inspectors, including the Chief Mines Inspector have been engaged at a number of the detailed risk assessment workshops.