The mine’s ventilation system was also found to be deficient, as were gas monitoring systems, and the misplacement of a ventilation fan lead to a problem of high methane levels underground.

The 400-page report, which was released by the New Zealand government yesterday, corroborated findings by the chief coroner that the men died instantly of oxygen depletion and noxious gases soon after the explosion on November 19.

“The board of directors did not ensure that health and safety was being properly managed and the executive managers did not properly assess the health and safety risks that the workers were facing,” the report stated.

“In the drive towards coal production, the directors and executive managers paid insufficient attention to health and safety and exposed the company’s workers to unacceptable risks. Mining should have stopped until the risks could be properly managed.

“The drive for coal production before the mine was ready created the circumstances within which the tragedy occurred.”

Former PRC chief executive Peter Whittall has pleaded not guilty to failures of methane explosion management, ventilation management, strata management and mitigating the risk and impact of an explosion.

Whittall could be fined $250,000 for each of his 12 charges, meaning he could be up for $3 million if found guilty.

New Zealand Prime Minister John Key reportedly said the management’s failure to discharge its responsibilities “had led to the loss of the lives of 29 men that would have been preventable if they'd done their job properly", according to a report by stuffco.nz.

A statement from lawyers representing former Pike directors John Dow, Ray Meyer and Stuart Nattrass, and Whittall, said their clients would consider findings of the report with which they did not agree.

The mine was new and PRC had not completed the systems and infrastructure necessary to safely produce coal, according to the report.

“Its health and safety systems were inadequate,” it stated. “Pike’s ventilation and methane drainage systems could not cope with everything the company was trying to do: driving roadways through coal, drilling ahead into the coal seam and extracting coal by hydro mining, a method known to produce large quantities of methane.”

There were numerous warnings of a potential catastrophe at Pike River provided by professional staff at the mine, according to the report.

“One source of these was the reports made by the underground deputies and workers,” it stated.

“For months they had reported incidents of excess methane (and many other health and safety problems).

“In the last 48 days before the explosion there were 21 reports of methane levels reaching explosive volumes, and 27 reports of lesser, but potentially dangerous, volumes. The reports of excess methane continued up to the very morning of the tragedy. The warnings were not heeded.”

But the report did not pinpoint the contentious reason for the actual ignition of the fatal explosion. It found it could have been any number of reasons, including a “frictional ignition” from mine activity, faulty electrical equipment , contraband, the non-flameproof underground fan or a diesel engine hot surface ignition.