Released 19 June 2017
Solid Energy says the Pike River Mine unmanned exploration project is making good progress and reiterates its previous statements that the video footage of the mine conditions does not in any way contradict the decision that manned re-entry is not safe.
The project team working on the unmanned exploration of the Pike River Mine has now completed the assessment of viable technology and identified a preferred option capable of going down a borehole, unfolding and then moving around.
This follows two major meetings with interested parties, including relevant government agencies, technical experts and an advisor to the Pike families, to scope out options and develop the exploration plan.
Solid Energy Chief Executive Tony King said that the thorough planning and preparatory process for unmanned exploration is necessarily time-consuming.
“There are already four abandoned robots in the mine – we need to ensure that any future unmanned exploration is conducted with the right technology to get the job done effectively.”
Mr King said that the robot selected as the preferred option is based on a stock item but with protective coverings removed to allow it to fit down a 150mm borehole. It will need to be built to a modified state, with all aluminium removed and replaced with other metals. If technically feasible a real-time gas monitor would be installed so that gas conditions in the mine could be monitored by the robot.
The project team is still assessing options for positioning of the boreholes that will need to be drilled through into the top of the drift for robot entry.
Mr King said that the project team had initially considered using an existing borehole for a trial however the initial risk assessment identified little benefit. The option currently being considered is to drill a new borehole in an unexplored part the drift to maximise the area of unexplored drift that the robot could cover. It is estimated that up to 200 metres of unexplored drift could be covered with one borehole, which would be a major step forward.
It is estimated that completing the necessary robot modification and planning and preparation of boreholes will require at least three to four months once the re-entry plan is signed off.
Solid Energy continues to provide fortnightly progress updates to the Pike families, who are represented by an advisor on the project team.
The reasons for Solid Energy’s decision that manned re-entry of the drift is not safe are spelt out in a comprehensive statement presented to the families in November 2014, well publicised at the time and available on the company’s website along with all of the technical documentation prepared by the company’s panel of experts.
“As we have previously said, there is nothing in any of the video footage that has been released that contradicts the ultimate decision that manned re-entry of the mine is unsafe”, said Mr King.
“The lack of damage evident in the video footage of Borehole 44 is consistent with what would be expected in the circumstances. We all saw the images of flames coming out of the shaft. These hot gases established an air current that drew air up the drift, into the fire and then up the shaft. The tendency in an underground fire is for it to burn back towards the source of oxygen i.e. the drift. The roof-fall at the end of the drift is probably due to heat damage, and extensive damage from there
through to the shaft and in adjacent roadways would be expected. The inner parts of the mine would be oxygen deficient and there would have been no air current to draw the fire into those areas.”
The company looks forward to progressing the unmanned exploration proposal and is hopeful that if successful this may finally provide some answers for the families.
For further information:
Mr Tony King, Chief Executive, Solid Energy New Zealand