NEW Zealand's Pike River Coal mine's managers were so focused on short-term coal production, they never considered the risk of an explosion, and missed the warning signs, the royal commission into the disaster that killed 29 men has found.
Two Australians, 25-year-old Joshua Adam Ufer and William John Joynson, 49, were among the miners killed on November 19, 2010.
The royal commission's report into the deadly underground explosion was made public by the New Zealand government on Monday.
It found the explosion was likely to have started in the centre area of the mine's workings, and was fuelled by methane.
However, it said the source of the ignition remains contentious, and could have been an electrical cause, such as the switching on of a pump in the mine; a diesel engine hot surface ignition; contraband taken into the mine; "frictional ignition" from activities in the mine; or sparks from the non-flameproof underground fan.
The 400-page report also concluded that the 29 men probably died instantly, or from the effects of noxious gases and oxygen depletion soon after the explosion on November 19, in line with the chief coroner's earlier findings.
The report highlights issues at numerous levels of the mine operations, including its management, with a culture that put production before safety.
There was "clearly an attitude of recklessness" in some quarters of the mine's workforce.
Although there was a lot of safety information about the mine's systems and practices underground - including the use of contraband, spikes in methane levels, ventilation problems, bypassing of safety devices, sensor failures and other issues - that information was not assessed or responded to.
The mine's safety management system lacked procedures that made specific people responsible for collection, assessing and responding to safety concerns, and commitment to health and safety from some quarters, including the company's board and mine management, was lacking, the commission said.
The mine's ventilation system was inadequate and had numerous issues, including the major error of the placement of the main fan underground, while its gas monitoring systems were also deficient, with workers sometimes deliberately bypassing sensors, and posed a very serious problem in the lead-up to the explosion.
There were also problems with the mine's electrical system, and the commission had significant concern about the role it may have played in the explosion.