In their evidence, the men were critical of the mine's operation, Mr Grieve said.
They were available to give evidence in person but the request for that to happen was declined by the commission.
Mr Grieve said his clients' complaint was that the men were never given a chance to be cross-examined on their evidence.
It was therefore not possible for the applicants to know what the evidence was and how adverse it was.
"They were people who had detailed experience into a range of matters into which the commission was inquiring and they were available to give evidence.''
Mr Grieve said the commission was set up to find the truth of what happened to cause the explosions at the West Coast mine in November 2010, in which 29 miners were killed.
Justice Young said he had the chance to file new evidence during the hearings but didn't.
"Didn't you paint yourself into a corner by deciding not to file the evidence?'' he asked.
Mr Grieve said while the applicants did not have new evidence, they should have been able to have the chance to question others who did have new evidence.
The hearing continues.