Workers staged a walkout over safety fears before a deadly explosion ripped through the Pike River coal mine, an inquiry into the tragedy has heard.
Johannes Strydom, a former electrician at Pike River, is delivering testimony to the second phase of the Royal Commission of Inquiry into the mine tragedy today.
Under questioning by Engineering, Printing and Manufacturing Union (EPMU) counsel Nigel Hampton QC, he revealed miners had consistently raised concerns with management about a lack of drift runners available for them to drive out of the mine in an emergency.
They had once walked out of the mine in protest, Mr Strydom said.
"There was at one stage a walkout where there was not a drift runner in the mine and people felt their safety was in jeopardy. They walked out."
Mr Strydom said he had concerns over whether the trapped Pike River miners would have been able to climb out a ventilation shaft designated as an escape route out of the mine.
He said it had taken him 45 minutes to climb the shaft while installing a cable.
Self-rescuers issued Pike River workers only contained 30 minutes of oxygen, he said.
"Taking into account that when you do physical exercise you use more oxygen... In my opinion, there's no way you could have made it."
Safety problems also arose when Pike River workers took self-rescuers that were not assigned to them, Mr Strydom said.
He complained to management when his self-rescuer was used without his knowledge.
Mr Strydom has now been excused from the commission.
Mine tragedy survivor Daniel Rockhouse has been called to the stand to read his brief of evidence.
'I thought I was going to die'
Mr Strydom earlier describing being forced to abandon his stricken colleague in the mine.
He was told to look into a power and communications outage at the mine after the first explosion there on November 19.
As he was about to enter the mine, he expressed his fears to a McConnell Dowell crew.
"I.... said to the deputy 'I hope this isn't bad'. I said that because of the fact I would not effect a power outage and a communications outage at the same time."
Mr Strydom said he found his colleague, explosion survivor Russell Smith, lying flat on his back with his arms above his head.
Training he had received in South Africa made him believe Mr Smith was dead.
"This was typically what we were taught what a person would look like if he had died instantly."
He broke down as he told the commission he could not rescue his stricken colleague due to harmful levels of carbon monoxide in the air.
"It was now impossible for me to breathe. The drift runner was losing power. I thought I was going to die."
Mr Strydom said power and communications outages had preceded six methane explosions at coal mines in his native South Africa.
He drove into the shaft despite his fears "something is wrong in this mine" and a lingering smell of cordite in the air.
"I knew people was depending on me. I could be wrong. It could have been some event that I had not thought of. It was absolutely important to get the ventilation into the mine back up and running as soon as possible."
Earlier, police Detective Senior Sergeant Nigel Hughes told the commission where the 29 miners who died at Pike River were thought to have been before the first explosion.
He said the projected positions were based on best guesses and visual evidence and may be inaccurate.
Hearing to focus on the search and rescue operation
Legal teams are set to question whether there was a "window of opportunity" to rescue the men trapped at Pike River.
Lawyers will ask whether there was a chance for rescuers to enter the mine in the immediate aftermath of the first explosion.
The structure of the rescue operation - which was headed by police - and whether Pike River Coal had adequate rescue equipment in its mine will also be scrutinised.
Mine survivor Daniel Rockhouse, police superintendent Gary Knowles, families spokesman Bernie Monk and Pike River mine manager Doug White are among the 26 witnesses set to take the stand.
The hearings are scheduled to run until September 23.