He revealed miners at Pike River placed plastic bags over gas sensors and used explosives to spread stone dust on the mine walls.
Counsel for Pike River Coal directorship Stacey Shortall today asked whether the 29 trapped men had done either of those things those things on the day they died.
Mr Rockhouse refused to speculate on the dead men's actions.
"I don't know for sure whether or not any of the Pike 29 were involved in such a thing.
"You hear things in the street second hand, third hand, fourth hand. I'm not going to speak ill of the dead. I'm not going to go there."
Mr Rockhouse said the mine blast was caused by a range of systemic failings affecting the entire Pike River Coal workforce.
He said the important thing was to retrieve the bodies of the men still inside the mine.
"The system of work has failed here. I'm not going to blame individuals. They've paid the ultimate price."
Accusations Whittall bullied safety boss
Former Pike River Coal chief executive Peter Whittall bullied and humiliated his safety manager in front of colleagues, the inquiry heard earlier.
Counsel for the families of the Pike River dead today asked Mr Rockhouse whether, on reflection, he had been a victim of bullying at the hands of Mr Whittall.
He conceded he had.
Mr Rockhouse earlier accused Mr Whittall of abusing him while he was giving a powerpoint presentation to mine management.
He said Mr Whittall had yelled at him, mocked him and slapped the wall with his hand, before "melting down" in front of managers.
The incident sparked one of his two attempts to resign from Pike River.
Mine Manager Doug White talked him out of his decision, urging him to take some "concrete pills" and telling him the mine would gradually improve.
Mr Rockhouse also conceded there were several major safety failings at Pike River, including the fact incident reports from miners were never passed on to management.
Other failings included a lack of in-mine monitoring to check whether safety systems were being implemented, he conceded.
He blamed his high workload for the lack of mine audits.
Mr Rockhouse yesterday said his son Daniel, who survived the first blast inside Pike River, had told him mine safety breaches were common.
Those included placing plastic bags over gas sensors, impairing the ability to pick up spiking levels of potentially explosive methane, he said.
He claimed explosives were used to help spread bags of stone dust against the walls of the mine - a process aimed at preventing coal dust explosions.
"I was absolutely gutted. I couldn't believe it. We'd put so much work into that place....It's beyond comprehension...
"The rules of mining are written in blood."
