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Mining Tragedy Revisited

Published: 28th Nov 2012 in OSA Magazine

The loss of 29 lives in the Pike River Mine Disaster of November 19, 2010 will be forever remembered as one of the darkest days in the history of coalmining in New Zealand. As an industry we are constantly aware of terms such as ‘Emergency Preparedness’ and ‘Emergency Response Management Plans’, and numerous seminars and forums are facilitated to study these topics in detail.

This begs the question, ‘How well is your organisation really prepared if it was faced with a major disaster such as that which occurred at Pike River’? The incident management team, mine manager, mines rescue and other emergency organisations responding to the Pike River mine explosion faced significant challenges on planning a re-entry into the mine by rescue teams.

Introduction

Coal mining disasters can occur from a variety of circumstances such as explosions, inundation of water or fires to name a few. Every incident will provide different and at times unique challenges to people charged with control and management of the situation. Incident management teams rely on accurate and reliable information available to form the basis of robust decision making processes.

An emergency event can rapidly escalate depending on the dynamic nature of the situation and can also deteriorate quickly on the back of poor decision making. The gathering, analysing and interpretation of information form a critical function of incident management. Obtaining information during an emergency can be particularly challenging as often a significant amount of diverse information is required quickly.

One of the most critical decisions to make in response to a dynamic incident such as an explosion, is the decision to deploy rescue teams into a mine.

This article provides an overview of the challenges that the incident controller, incident management team and mines rescue officer in charge were faced with in the hours following the explosion at the Pike River Mine.

The author would like to note that at the time of submitting this article the Royal Commission of Inquiry on the Pike River Coal Mine Tragedy was still sitting. Every endeavour has been made to ensure that this process is not jeopardised by the inclusion of subject matter that is subjective or still before the Commission. This paper is not intended to cut across the vital Royal Commission in any way, but rather to provide summary information in the context of the Coal 2012 Conference.

Events of November 19, 2010

At 3.44pm the control room officer was talking to a miner underground when communications were suddenly lost. At the same time the computer monitoring system started alarming and indicated that power had been lost underground. The control room officer attempted to contact personnel throughout the mine but was unable to raise anybody. He contacted the mine manager who was in a meeting with other senior mine officials and informed him of the situation.

The mine manager discussed the loss of power with the engineering manager, who subsequently arranged for an electrician to go underground to investigate possible faults at the main electrical bay. The loss of power was not an unusual occurrence at the mine due to the fact that the mine was at the end of a main supply and had been damaged on previous occasions as the line was close to trees.

The electrician entered the mine in a drift runner and after driving 1,500m he came across a loader and a man lying on the ground. At this point he suddenly found breathing difficult and his vehicle was losing power. He returned to the surface and contacted the control room to report his observations and stated that he believed that there had been an explosion in the mine. The management initiated the mine emergency response procedures.

Phone call from survivor

At approximately 4.35pm, 50 minutes after the explosion, a phone call was received from the pump bay area which is located 1,900m into the mine. A miner who had survived the explosion spoke to the mine manager and stated that he could hardly breathe and the mine was full of smoke. The manager told him to stay low and start making his way down to the mine portal. He managed to make his way down the main tunnel until he came across the other survivor who was in a semi-conscious state. The miner then continued out of the mine dragging his colleague with him and both men exited the mine at 5.25pm, almost 90 minutes after the explosion.

The men were treated by Paramedics and immediately taken to hospital. No information could be obtained from the men prior to leaving the mine due to their poor physical condition.

Mines rescue response

At 4.30pm the Rapahoe Mines Rescue Station received a call from the Pike River Mine control room and the caller stated that they believed there had been an explosion underground. The staff at the rescue station initiated the emergency response procedures and began the task of contacting brigade personnel. Three teams were assembled at the station within 30 minutes and breathing apparatus and other essential rescue equipment was readied for deployment.

The first two teams were transported to the mine site by the local rescue helicopter and an additional two teams travelled to the mine by road. The rescue helicopter had the first rescue team and Officer in Charge on site at 6pm. On the approach to the landing site the Mines Rescue Officer in Charge instructed the pilot to fly past the return ventilation shaft.

The sight of the damaged évasée was confirmation that a significant explosion had occurred. In addition, soot was observed in the trees across the valley directly in line with the outlet of the évasée and smoke was seen to be drifting from the return shaft.

When mines rescue arrived at the mine site the mine manager stated that no-one, including rescue teams, was to enter the mine due to a lack of information on the underground environment. By 6.20pm four fully equipped mines rescue teams were on site and were completing preparation of their equipment and planning strategies for a rescue operation. 

Subsequent explosions

The second explosion occurred at 2.37pm on November 24. It came as a devastating blow to the families of the 29 men as it was clear from video footage that this explosion was not survivable. Many families had clung onto the hope that their loved ones had survived the first explosion and were still alive in the mine. The news of the second explosion crushed those hopes. It was officially announced that the operations had moved from one of rescue to that of recovery.

A third explosion occurred on the afternoon of November 26. This explosion was not as violent as the previous explosions but reinforced the urgency that was required to seal the mine.

On the afternoon of November 28 the fourth extremely violent explosion occurred. The force of this explosion blew the seven tonne évasée off the top of the ventilation shaft, landing some distance away, and thick black smoke clearly indicated that a large fire was now burning in the mine.

A few hours later flames emerged out of the shaft and these were initially up to 50m high. The fire raged for another 11 days before the flames were finally extinguished with the use of the Queensland Mines Rescue GAG unit. Following the fourth explosion a major fall occurred in the main access tunnel as the natural ventilation flow into the mine ceased.

Information required for the rescue teams’ deployment

In the early stages of this incident it soon became apparent that there was a lack of critical information available to the incident management team. The mine manager had given a clear directive that mines rescue teams were not to enter the mine due to a lack of information on the atmospheric conditions underground. This position was maintained by the NZ Police. The author fully supported this decision.

In the hours and days following the first explosion, the NZ Mines Rescue focus was on gathering critical information on the underground atmospheric conditions. Until such time that accurate and reliable intelligence could be analysed and interpreted, the level of risk associated with the deployment of mines rescue teams could not be adequately determined or fully understood.

Known information

The known information available was extremely limited, but of significant importance to determining the level of risk associated with the deployment of mines rescue teams. It is described as follows:
• The Mine Manager and the Mines Rescue Officer in charge had flown over the return shaft and viewed the damaged évasée and adjoining infrastructure. This observation along with soot in trees on the side of the valley opposite the évasée was confirmation that a significant explosion had occurred
• Smoke was seen to be drifting out of the return shaft. This was a critical piece of information as it had to be accurately determined if the smoke was a product of the explosion or combustion that still remained in the mine
• The mine had a high gas make. Information provided stated that the gas make from the upper workings of the mine was approximately 200 ltrs/sec. Only six weeks prior to the disaster the main fan on the surface malfunctioned and the entire upper mine workings ‘gassed out’ in a few hours. NZ Mines Rescue was called to assist with this event so was well aware of the mine gas make
• The mine gas drainage line had been fractured somewhere underground. Information provided indicated that this may be delivering up to 800 ltrs/sec into the mine in addition to the normal mine gas make. Approximately 1,000 ltrs/sec of methane was filling the upper workings of the mine. Total void volume of this area was approximately 50,000m3
• The main ventilation fan was located underground and power was off. It was considered highly probable that the ventilation control devices in the mine would be destroyed, particularly the double doors in the first crosscut between the intake and return shaft
• Natural ventilation was entering the mine due to the inclined main tunnel and elevation differential between the intake portal and return shaft. Sufficient oxygen would be present to support further explosions (the quantity of air was measured at between 12 – 15 m3/sec)
• The gas monitoring system had been lost as the mine only had a real time monitoring system installed. There was absolutely no intelligence on the underground atmospheric conditions

To summarise, this was the information known in the first few hours of the incident. A significant explosion had occurred in the mine, there was a high make of methane, smoke was coming out of the return and there was natural ventilation into the mine. Of the three main factors required for another explosion, two were present and the third (an ignition source) was possible and had to be suspected.

Additionally, the following information was known:
• Video footage of the windblast exiting the mine portal had been viewed. When the size of the mine is taken into consideration, the significance of the video footage is brought into perspective. This was a very small mine and a 52 second windblast was recorded exiting the mine portal. Excluding the void volume of the main access tunnel, the total volume of all mine workings was approximately 80,000m3
• Two men had survived and walked out of the mine, one hour and 45 minutes after the explosion
• Possibly 34 men unaccounted for underground. The correct number of men missing was not confirmed by Pike River Mine until ten hours after the explosion
• No communications had been received from any other locations in the mine. Additionally, mines rescue personnel had lowered a radio down the slimline shaft into the area known as the ‘fresh air base’ and remained at this location for many hours
• There was only one practicable means of egress from the mine via the main, 2.4km main access tunnel. The second means of egress was via the return shaft which would not have been possible following the explosion. The main drift was also the only access for rescue teams to re-enter the mine but this route meant they would have also been in direct line of any secondary explosion. The walking time to the top end of the main tunnel under normal circumstances was approximately 45 minutes
The walking time for rescue teams would have been considerably longer given the equipment the rescue teams were required to carry. If rescue teams were required to be withdrawn due to changes in the underground environment this could not have been achieved within a period of time acceptable to mines rescue. A loader operated by one of the survivors was blocking the main tunnel at 1,500m, which precluded the use of vehicles beyond this point
• The workforce at the mine was trained to self-escape and all underground personnel were equipped with 30 minute self-contained self-rescuer units
• There was a cache of approximately 100 self-contained self-rescuers stored in the fresh air base at the slimline shaft
• There were no boreholes into the upper workings of the mine to obtain gas samples
• The real time gas monitoring system had been lost. There was no road access to the return shaft; helicopters were required to obtain gas samples for gas chromatograph analysis at the mines rescue station. Only three samples were obtained in the first few hours as poor weather conditions prevented helicopters from flying until the following morning
• The first gas samples analysed were highly diluted due to the difficulties in obtaining samples and the natural ventilation short circuiting through the first crosscut. These two factors meant that the gas samples obtained were not truly representative of the underground environment.

Unknown Information

• What was the composition of the atmosphere underground? This was perhaps the most significant issue facing the incident management team. Without accurate and reliable intelligence on the underground environmental conditions, it was not possible to adequately determine if there was an acceptable level of risk to deploy rescue teams into the mine
No intelligence from within the mine, coupled with the fact that smoke was observed at the return shaft, meant an ignition source had to be suspected as it could not be eliminated
• What was the ignition source and did it or a secondary ignition source still exist underground? It was absolutely critical to ascertain if an ignition was present as it was highly suspected that a large volume of methane would be present in the mine
• Where in the mine did the explosion occur?
• Was the smoke drifting from the return shaft, the product of Afterdamp or combustion?
• What was the location of all the men working in the mine?

Obtaining critical information

Obtaining gas samples, temperature and pressure readings from within the mine was a top priority. Samples were obtained from the ventilation shaft hourly and analysed by parallel gas chromatograph analysis at the mine’s rescue station and mine.

Obtaining gas samples was extremely challenging, however. The only access to the return shaft was by helicopter and to travel by foot was a six hour round trip on foot in steep, mountainous terrain. Highly diluted samples from the return shaft meant there was no confidence in the data. Frustratingly, there were no other sampling points available from the upper mine workings.

Early interpretation of gas data from the return shaft was that there was a strong likelihood that a fire was burning in the mine and that this could be a clean burning methane fire.

In the early stages of the incident it was identified that additional boreholes were required. Suitable locations were ascertained and an expert drilling team was quickly assembled. A suitable pad was constructed at the drill site with helicopters used for transporting all equipment and personnel. Crews worked around the clock to drill the 165m into the mine, where the drilling rate was slowed by the very hard rock encountered.

Gas samples were taken following the completion of the borehole and it was felt that a methane fire was burning in the mine – later confirmed when a second, violent explosion occurred in the mine.

Complexities of disaster

Along with the many challenges that continuously tested the incident management team, this was a complex incident on many different levels.

From a human factor perspective, it is difficult to fully articulate the effect that an incident of this scale and magnitude had on all those involved in the rescue efforts. The West Coast of New Zealand is a small, tight knit community and all the men who lost their lives in this tragedy were well known to many of the people involved in the rescue efforts.

Highly trained mines rescue personnel were desperate to enter the mine. Eventually this desperation turned to despair and immense frustration as time went on, as no rescue operation could be launched. The professionalism of the rescue personnel came to the fore, however. The rescue teams remained in a high state of operational readiness and continuously worked on developing strategies that would be implemented if an acceptable level of risk was determined to allow entry into the mine.

The raw emotion that was displayed when mines rescue teams and all those involved in the incident were told of the second explosion is difficult to express. This is the moment that even the most remote hopes of a miracle were lost and the terrible realisation that 29 family members, friends and colleagues are dead.

The mountainous, inhospitable terrain tested the toughest of men and if it had not been for the skills of the highly experienced helicopter pilots, the work required to obtain gas samples would not have been possible.

Summary

The challenges of gathering information in the early stages of the Pike River Mine disaster impacted enormously on the rescue efforts.

This disaster has been and continues to be complex and challenging. To fully encapsulate all of the complexities and challenges associated with this tragedy in one paper would be virtually impossible. 

Published: 28th Nov 2012 in OSA Magazine

Author


Trevor Watts


Trevor Watts is the General Manager of the New Zealand Mines Rescue Service. Trevor has had a total of 27 years with the New Zealand Mines Rescue Service including 19 years as a brigade member. He has attended a multitude of callouts to mine fire situations and was a member of the rescue team deployed to the 1985 Boatmans Mine Disaster on the West Coast, in which four men were killed by carbon monoxide poisoning produced from a mine fire.

Trevor has been responsible for all Mines Rescue operational activities during and following the Pike River Mine Disaster, where 29 men lost their lives in a methane explosion on November 19, 2010.

New Zealand Mines Rescue Service

The New Zealand Mines Rescue Service was established in 1930 and employs six full time staff, the General Manager, three training officers and Administration Officer based at the Rapahoe Rescue Station on the West Coast of the South Island, and a Station Manager based at the Huntly Rescue Station in the North Island.
At the time of the Pike River Mine Disaster, the New Zealand Mines Rescue Service brigade strength consisted of 24 underground rescue personnel in the North Island and 33 underground personnel on the West Coast of the South Island. Additionally the West Coast has 30 surface rescue personnel.


Trevor Watts

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