Incidents such as the explosion which ripped through Pike River mine killing 29 men should not happen in modern mining, the chief executive of Solid Energy told the royal commission of inquiry in Greymouth yesterday.
Don Elder said Pike River Coal always had a high chance of financial failure and that "prolonged production and financial under-performance" had the potential to create safety risks at the mine.
The inquiry is looking into what caused the deaths of 29 workers in explosions at the West Coast coal mine last November, and Dr Elder - whose company is now seeking to buy the Pike River mine - was the first person to give evidence.
This first phase of the inquiry is intended only to provide context for the commission, but tensions soon arose as Dr Elder gave his blunt assessment of the mine and its management.
"Incidences like this, with catastrophic consequences, shouldn't be able to occur in modern mining," Dr Elder said.
"I didn't believe it remotely likely that this event could have occurred ... if all practicable steps had been taken."
Dr Elder's claims drew a sharp response from a lawyer for Pike River directors, officers and managers, Stacey Shortall, who put it to him that he was speculating.
Asked by Ms Shortall if the Pike River mine would have been a competitor to Solid Energy's Spring Creek mine on the West Coast, Dr Elder said: "I don't believe Pike River was ever a competitor to Solid Energy."
Dr Elder agreed with Ms Shortall that his company had pleaded guilty on three occasions to breaches of health and safety legislation.
He also agreed he had not contacted Pike River Coal's last chief executive, Peter Whittall, or operations manager Doug White, to discuss with them financial under-performance and links to safety.
Earlier, commission lawyer James Wilding told the inquiry many issues would be considered, including whether financial pressures had affected health and safety at the Pike River mine.
Some relatives of the 29 dead workers - whose remains are still trapped in the mine - were in the public gallery at Greymouth courthouse for the first day of the inquiry yesterday. Some wiped away tears as support from around the world was mentioned.
Mr Wilding said the families' patience since November had been extraordinary. The inquiry over the coming months would test their patience further "and for that we are sorry".
Families' spokesman Bernie Monk said: "This is the start of a big journey."
The families' lawyer, Nicholas Davidson, QC, said the families wanted to get to the truth "irrespective of the consequences".