The following report was compiled from talking to actual workers at Pike River Mine. People who were employed there before the explosion and as part of the attempted recovery operation after the explosion. The information was supplied to me in good faith from people I personally trust. They have no motivation that I know of to report incorrect claims.
A) Preliminary drilling at the site before the mine was established showed the in situ coal to have extremely high levels of gas. The gas levels were so high, experts expressed doubts concerning the practicalities of mining it by underground methods. However as it was a given that open cast mining would not be permitted by the Department of Conservation and also that the economics of removing the overburden were doubtful, the decision was made to proceed with the underground option.
B) During the actual mining of the coal it is normal practice to horizontally drill long holes into the face of the seam to plan drilling and extract gas prior to the coal’s removal. My sources have said that when such holes were drilled, the rate of methane gas exiting from the in seam holes was as high as 100 litres of gas per second.
These two measures ( A and B), the gas in the preliminary drill holes and the gas escaping while drilling the long holes indicated that gas levels in the mine were extremely high. This naturally made the risks of mining it by underground methods also extremely high.
These risks could have been mitigated and perhaps managed by advanced air extraction methods. Keeping the mine well ventilated. However my informants claim that DOC refused to allow (verification needed) the construction of a second large diameter (around 4.15m) ventilation shaft. There was one smaller diameter (660mm) ventilation shaft constructed. So there was only ever one full sized shaft built in a mine known to have extremely high levels of gas. I do not know what factors governed where this one large diameter shaft could be built, however, experts have claimed that it was poorly positioned in terms of the inclines or slopes within the mine. The mine floor actually sloped up and away from the shaft leading to a situation where gas could accumulate quickly if extraction systems ever failed.
Given the high levels of gas, there should have been more than one main ventilation shaft. This raises the question- should experts have allowed the mine to proceed with only one main shaft, and that one shaft placed in a position that was probably not optimal?
My sources tell me that the electrical system providing the power that worked the extraction fans was never reliable. That it was in constant need of attention. In fact, the system had developed a problem and the electrician was on his way to repair it at the time the explosion occurred.
It is known that if methane/oxygen content reaches a certain level in a mine, it can be ignited and will burn.
This then gives us the logic trail that leads to the explosion. High gas content of the coal. Poorly designed and ineffective ventilation. Failure of the ventilation system’s power supply. Gas builds up quickly to explosive levels. An ignition event. Explosion and fire.
Sources also claimed that the more experienced workers were worried by the presence of inexperienced workers who increased the risk of explosion through their unawareness of the need to eliminate sparking through collisions of metal on metal.
So in the mining operation itself we have an extremely high risk operation- high gas content, insufficient ventilation, and inexperienced workers. My sources tell me that the feeling among experienced coal mining locals was that the mine was always a dangerous operation and that an explosion was something they all feared on a daily basis. Risk can be managed. Was it poor risk management at the root of the disaster, or was the risk always going to be too high to manage?
C) Underground mines usually have safe rooms. These are sealed rooms at strategic sites where workers can take refuge in case of fire or other threats. They have supplies of oxygen, food and water and usually a drill hole leading to the surface for air supply. Pike River Mine, in spite of the known risks, had no safe rooms. Miners were issued with breathing kits but these only allowed around a half hour of oxygen.
Why, in an operation that was so high risk, was there not one or more safe rooms? I have been told that the construction of these safe rooms was somehow blocked by DOC, but this is an unclear and unverified allegation that needs to be investigated. All I can suppose is that the destruction of flora and fauna that the drilling of the safe room ventilation shaft entailed made it unacceptable to DOC.
The lack of safe rooms becomes more important when it is suspected that not all miners were instantly killed in the blast. My sources maintain that there were men working some distance from the area of the explosion and it is highly likely they survived as investigation cameras lowered into the mine after the explosion showed no bodies where the men were known to be working.
These same cameras showed no damage from the explosion in these areas. There was no force of impact visible on equipment. For example a pallet of dust sacks at the work face was still encased in the plastic wrapping and the wrapping showed no heat effects. Sources claim that up to 19 men were working in this area. Given that no bodies were visible, this indicates that the men most likely donned their breathing apparatus and attempted to find a route out of the mine. A route that never existed. With only a half hours supply of breathable air, they were doomed. The gas meters lowered into the mine through the drill holes showed a 98% methane level.
Could these men have been rescued if safe rooms had been constructed?
Why did the men agree to work in the mine when the risk was so high? I don’t know the answer to that question. However it is known that PRM had agreed to pay a $9000 bonus if a certain amount of coal had been extracted and made ready for shipment before a certain date. My sources also claim that men who had complained of the high risk of the operation had their employment prematurely ended. This is unverified. Sources also claim that locals aware of the high risk always expected an explosion was going to occur at some stage.
Finally, my sources report that the rescue crews from Australia expressed disbelief at the poor levels of risk management and general safety at the mine, remarking that the New Zealand operation in terms of safety management, was a light year behind similar operations in Australia.
So the questions that arise from these reports are- Where was the government department responsible for coal mine safety management during operations at the mine, and what part did they play in approving a mining operation that, if the reports above are true, should probably never have been undertaken. Why was the risky mining operation, into high gas content coal, approved with only one major ventilation shaft and no safe rooms? Why, when operations at the mine showed a high risk of explosion, were the operations not stopped by safety and risk management regulations? ? Are there regular safety inspections of such operations by government mining inspectors? One would have to assume there are none or the explosion would never have occurred.
If my sources are correct, the information they have supplied brings into question the decision to proceed with the mine. Who was it in the end that made that decision? One would have to assume it would be PRM directors and management, and NZ mining regulators. Clearly the decision was incorrect. Let us hope the upcoming inquiry sheds light on exactly what lead to a decision that in the end resulted in such a terrible tragedy.