Former monitor deputy Stephen Wylie had done hydro mining at Solid Energy's Spring Creek underground mine, near Greymouth, but was moved to a similar position at Pike River without training - or even applying for the post, the Royal Commission of Inquiry was told.
He was on the shift before the November 19 explosion, and was the last person to view the area being mined by high-pressure water.
The commission regards the hydro monitor being used to cut the coal as its "prime suspect" for causing the explosion that killed 29 men. It is considering whether a collapse at the coal face had pushed a wave of explosive gases through the mine. Mr Wylie's crew was far less experienced than the incoming shift, who all lost their lives - Peter O'Neill, Allan Dixon and Richard Valli.
"I noticed nothing in the goaf that was any different [the day of the disaster]," Mr Wylie told the hearing.
Methane levels were low, and there were no unusual smells or sounds. The goaf - the cavity left by mining coal - was up to 9m high that night. Somewhere in the back, there would have been 100% methane, he said.
"At some stage it was going to collapse."
However, the coal left holding the roof up was very hard and it was unlikely the incoming crew would disturb the goaf.
Mr Wylie finished work at 8am on November 19.
He became monitor deputy in October 2010, eight months after joining Pike River as an "out-bye" deputy.
He transferred there without any training: "I didn't apply for the position, and I was just told. I managed the situation as best I could."
His trainee Craig Reyland had worked for Chris Yeats Builders and had no face mining experience. Mr Wylie had to leave the hydro area to do gas checks, but would "zip" back as soon as possible.
He would relieve the operator, who was sitting in the cold wind just pulling levers for a whole 12-hour shift. The person could get complacent, whereas at Spring Creek staff alternated hourly.
Earlier yesterday, the commission heard that hydro mining co-ordinator George Mason was previously the under-manager at two Australian mines that had exploded, claiming 23 lives.
He voluntarily surrendered his certificate of competency in 1995.
In 2007, he re-entered the industry as a miner, after a stint as a professional fisherman.
He did not relay an international mining expert's concerns about ventilation to managers.
Engineering, Printing and Manufacturing Union lawyer Nigel Hampton QC said criticism after the 1994 Moura disaster related to failures to communicate things to management.
"I thought things were under control," said Mr Mason, who still works for Pike River Coal (in receivership) as the mining co-ordinator.
- Greymouth Star
