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Pike River Inquiry Phase 3: Fundamental design flawed

A Japanese mining expert tells how Pike pushed ahead without adequate systems and safeguards.

Mining expert Masaoki Nishioka yesterday completed gruelling evidence describing how Pike pushed ahead with hydraulic mining before it had adequate systems and safeguards in place.

The fundamental design of the Pike coal mine was so flawed that fixing it would have required the company to stop production for six to 12 months, Nishioka told the commission. But by the time he arrived at Pike in July 2010 to install and commission the company’s critical hydraulic mining system, key decisions on mine layout had already been made and it was too late to reverse them. Among the flaws listed by Nishioka at the inquiry was the positioning of the mine’s major new ventilation fan underground, rather than at the surface. This meant that whenever methane levels rose above safe limits, the fan would trip out.

The section of the mine that Pike had designated for its first foray into hydraulic mining was also too close to the Hawera fault, which was known to release very high levels of methane gas.  There was no second means of egress, and while the 108 metre vertical ventilation shaft was nominated as an exit way, in practice it would have been like trying to escape up a chimney.

Nishioka, an international expert in hydraulic mining methods, left Pike on October 20, frightened the mine could blow at any time. He told the commission he gave “strong” advice to both Pike chief executive Peter Whittall and mine manager Doug White that ventilation in the gassy mine was inadequate, and that hydraulic mining should not proceed until the new ventilation fan had been commissioned. He told them conditions underground were “really bad”.

Daily notes written by Nishioka during his time at Pike reveal that methane levels repeatedly rose to 5% and above (the explosive range is 5-15%), the ventilation fan frequently tripped out, and he suspected the mine’s power supply was insufficient.  He worried that the many contractors working underground were not under tight management, and in one entry observed that some did not even know their way to the access tunnel.  When the new underground fan was turned on for the first time on October 4, it sent sparks flying.

There was production pressure from both the cash-strapped company, which needed to get coal out for a shipment to India, and from the workers, who were promised a $10,00 bonus if hydraulic mining was operational by September 24. But commissioning was plagued with difficulties, frequent stoppages and poor productivity. Nishioka often stayed underground until 9.00 or 10.00pm trying to sort out problems. He said Pike did not have an adequate system of draining methane away from the mined-out area  (known as the "goaf").  “I don’t think anyone had any idea how to handle the methane that accumulated in the goaf.”

Pike’s production manager, Pieter van Rooyen, had told him he wouldn’t go underground because it was “so scary”. Nishioka – who estimated he had been down 50-60 coal mines around the world in his 40-year mining career – said the only other time he had felt as uncomfortable as he had at Pike was in a Chinese hydraulic mine.

Lawyers for White and Whittall hit back hard at Nishioka under cross examination, saying that their clients denied ever being told by him that workers should not be sent underground until ventilation was improved and the second exit created. Paul Radich, acting for Whittall, asserted that the production bonus for workers was merely to mark “an achievement” at the mine and to create goodwill with employees. Nishioka, in his heavily-accented English, replied: “I think, you know, that the bonus system encouraged all the workers to produce coal.” He later commented that bonus systems in mining encouraged workers to push production and “forget safety … That is very risky.”

Radich also accused Nishioka of having no knowledge of Pike’s financial situation, and said his claim that the company couldn’t spend money on equipment such as better methane sensors was without foundation. Nishioka responded that he knew of the company’s financial position because he read about it in Pike’s corporate literature and news reports. “I knew, you know, the finance was getting really tight in Pike River operation.”

Nishioka was applauded by Pike family members in the public gallery when he left the witness stand after his gruelling day-and-a-half of testimony.