Tragedy at Pike River Mine - How and why 29 men died
BOOK EXTRACT: Tragedy at Pike River Mine: How and why 29 men died, by Rebecca Macfie, (Awa Press, $40)
In researching the book, Rebecca Macfie interviewed more than 100 people involved with the mine, from management to miners, geologists and contractors, Mines Rescue workers for whom
Pike remains an open wound, and families of men who died.
Business writer Rod Oram describes Ms Macfie’s book as “investigative journalism at its very best”. Readers will learn of an appalling string of mistakes, from consent being given for the mine in the first place, to lack of proper monitoring equipment, pressure to ignore safety requirements, and effectively only a single exit.
Although much of this has been revealed through the Royal Commission that investigated the disaster, Macfie also discovered new material, and in her hands the complete story becomes a page-turning if horrifying read. She says her aim was “to make the Pike story understandable to a wide audience – for the families, friends and colleagues who grieve for the 29 men, for New Zealanders who want to understand how such an avoidable disaster occurred in their midst in the 21st century, and for the leaders of businesses and organisations who must learn from it.”
Former NBR reporter and Unlimited editor Rebecca Macfie is a senior writer with New Zealand Listener. She has 25 years' experience in journalism and has won many awards including her latest, the 2013 Canon Media Award for best magazine feature writer (business and science).
The third anniversary of the Pike River mine disaster is Tuesday November 19.
MORE: New expose of Pike River disaster talks of failures at every level (NZ Herald)
Chapter 8: Marching to Calamity
Peter Whittall could scarcely have chosen a better-qualified person to come to Pike and oversee the commissioning of the long-awaited hydro-mining system. From early in his career as a mining engineer, Masaoki Nishioka had been involved in pioneering the system in his own country, Japan, as well as in Canada and New Zealand. He was, without doubt, a world authority on the method.
Hydro mining, which uses a high pressure jet of water to carve coal from a coalface, was found to be particularly well suited to the thick, steeply inclined and faulted coal seams of New Zealand's West Coast. It had been used as the main extraction method at the Strongman No. 2 mine from 1994, and at Spring Creek mine from 2004. Where other methods of mining would tend to leave large volumes of valuable coal behind in the geologically disturbed seams of the mountainous terrain, the hydro method could flush out virtually the full height of a coal seam.
Nishioka was familiar with Pike's plans to use hydro mining to extract 80 percent of its coal, and over the years he had answered numerous email requests for information from the company's former director and consultant Graeme Duncan. In 2008 he was asked, through his employer Seiko Mining, to draw up a plan for a hydro system at Pike and to put forward a price to supply the many items of equipment needed. However, Pike had decided to purchase most of the equipment from a supplier in Australia (where hydro mining was virtually unknown), and Seiko was contracted to supply only the water gun to cut the coal from the face and the pipeline to carry the coal slurry away.
Nishioka had heard through the mining grapevine that things weren't going well at Pike, and was concerned that if the mine failed it would give the hydro method a bad name. If the system didn't work at Pike, he thought, it would be because of a failure of management, equipment or mine planning, rather than the technique itself.
As it turned out, an email from Whittall arrived in his inbox in mid June 2010, when he was working in Saudi Arabia on an oil plant installation. Whittall wanted to know if Nishioka were available to come to Pike to help in the `ramp-up of operations' and become involved in a 'final critique of the installation, and also in the development and implementation of workforce training'.
When Nishioka arrived at Pike he was confronted with a situation that was much worse than he'd expected. There was a great rush on to finish developing the roadways that would give access to the first panel of coal to be extracted by the hydro system, as well as to install the water pipes, sumps and pumps required. But the mine's core infrastructure wasn't ready for hydro mining to begin. It was still reliant on the small backup fan located at the top of the ventilation shaft. The main fan, which would be the mine's principal source of ventilation, was not yet installed. And there was no emergency exit.
The hydro-mining equipment Pike had purchased from Australia was poorly designed. The pump that would feed water to the hydro monitor was unsuitable and had to be modified. The joints connecting the pipeline carrying high pressure water were prototypes; they leaked and appeared in danger of rupturing.
And the company had introduced unnecessary complexity into the system, making it more difficult for the miners to use. In particular, a machine called a guzzler was to be positioned about 18 metres behind the hydro monitor. Workers were to operate the monitor using levers located at the guzzler, which had enormous steel wings to capture the coal as it was flushed away from the face. This made the whole system clumsy and unwieldy to move whenever it came time to pull back to a new position to cut a fresh section of coal. The guzzler was yet another Pike prototype: it had not been used in a hydro-mining operation before.'
Nishioka was also unhappy about the area that Pike planned to start mining with the hydro system. The designated location was very close to pit bottom in coal, the section of the mine that would be a busy transit point for men and machines, and would house electrical, water and coal transportation infrastructure for the entire 18-year life of the mine.
It was also near the Hawera Fault, an area high in methane gas that had migrated into cracks and fissures. Once the coal had been extracted, the goaf - the mined-out area - would be sealed off, but the residual coal and rider seam, the thin layer of high-ash coal above the main seam, would continue to emit methane. The goaf would therefore become a huge pocket of gas close to the nerve centre of the mine.
In Nishioka's view, sound and conservative mine planning would have seen roadways driven by continuous miners out to the western limit of the mine, with hydro extraction starting there and gradually retreating back towards the pit bottom area.
But Pike didn't have time to push out to the west and work back. It needed coal now. Under the original access agreement with the Department of Conservation, hydro mining was supposed to have begun in a location well to the west. The department had specified an area for 'trial' mining where it wanted to assess whether hydro mining would cause subsidence of the land above.
But because Pike was plagued by endless delays and enormous cost overruns - the tunnel that took twice as long and cost twice as much as expected, the ventilation shaft that collapsed and had to be patched up, the thick stone graben that no one knew was there and took months to penetrate - it went to the Department of Conservation and asked for permission to start trialling the hydro system close to pit bottom. In the spirit of cooperation and goodwill that had developed between the department and the company, DOC agreed.
The first panel to be hydro-mined became known as the 'bridging' panel - so named because it would bridge Pike's financial gap by providing early income from coal sales.
By the time Nishioka arrived in July 2010, the choice of location, like the choice of equipment, was set. 'It was,' he would say, 'too late to rectify the mine plan." Nevertheless, he expressed his concerns about the set-up. He told Doug White he would not send men underground without adequate ventilation and a second means of exit, and he spoke strongly to Whittall of his concerns about ventilation and the design failings of the hydro system.
Nishioka was, by nature, courteous and polite. People who had known and worked with him for decades had never seen him raise his voice, or swear in frustration or anger. Slightly built and deferential, he may have felt somewhat apologetic about presenting the most senior people in the mine with such profound complaints. After all, he was effectively telling them their operation was poorly conceived, badly run and unsafe. In any event, his message was apparently not heard by either White or Whittall: both have denied he raised these concerns with them.'
The pressure to produce coal was palpable. On July 5, three weeks before Nishioka arrived, Pike chair John Dow had written to all employees offering a lucrative bonus payment if the hydro-mining system were up and running by September 3. If the target date were met and 630 metres of roadway development had been completed, each of them would get $13,000. The inducement payment would abate quickly for every week that the target date was missed: if start-up didn't occur until September 24, the bonus would fall to $10,000 (provided 790 metres of roadway development was completed). For every week of delay thereafter the payment would decrease by $2,500. The targets were 'readily achievable', Dow told employees.'
Assuming the workers earned the bonus and remained on the payroll, they would receive the money just before Christmas. It would be a handy boost to the festive season finances of men with families and mortgages.
The many contractors engaged by Pike to install underground infrastructure were not offered the bonus, however. Their exclusion was the cause of bitterness, given that many of them were small local operators and one-man-bands who were putting in huge hours at Pike to help the mine meet production targets.
As was his habit, Nishioka kept a detailed daily record of his activities. Through July and August he familiarised himself with Pike's wider production system, and made observations about activities in other parts of the mine. On August 6 he noted discussion at a mine planning meeting about the unresolved matter of the lack of an emergency exit from the mine.
On August 9 he wrote: 'Both faces are getting high gas content (0.4 percent) when [continuous miners] are not cutting. Need more ventilation air: The following day he commented on the muddy, messy state of roadways, and noted 'many contractors are working underground. Some of them do not know the way to go out of the mine: He noted: 'Smell of diesel fumes is bad. ... Main fan installation shall be commissioned as soon as possible.
Despite his reservations he pushed on, feeling unable to refuse to do the job he was contracted to do. 'I accepted adviser's work ... I have to do something. I cannot stay in the office sitting back on the chair and everybody was coming to me and [saying], "When can we produce coal?" I was getting, you know, that sort of pressure every day."
But he feared that Pike did not have a sound appreciation of the particular risks associated with hydro mining, and how those risks differed from other forms of mechanical mining. Continuous miners and roadheaders have a known production rate.
Assuming the methane content per tonne of coal has been properly assessed, the amount of gas that will be released into the mine atmosphere can be calculated, and the amount of ventilation required to keep gas to a safe level can therefore be worked out. But hydro mining can cut through very large volumes of coal quickly, resulting in big surges of methane that need to be flushed away by the ventilation circuit and diluted to a safe concentration as they are carried out of the mine.
A large goaf mined out by a hydro monitor also presents the risk of a massive cave-in. Generally, the practice is to induce small controlled cave-ins as mining progresses. This reduces the risk of a major uncontrolled collapse that will generate windblast - a violent surge of methane, air and debris that can kill or injure workers and damage machinery and stoppings. Nishioka understood that Pike, which had to avoid surface subsidence under its agreement with DOC, was not planning to induce cave-ins; it expected the roof to remain intact. He regarded this as contrary to good mining practice.
Nishioka was by no means alone in his concerns about Pike's premature rush into hydro mining. The company was on the verge of introducing a major new coal extraction system that carried specific risks, yet a thorough process for assessing those risks and documenting how they would be managed had not been undertaken.