A report following an eight-month investigation by Steelworkers Local 6500 alleges nickel mining giant Vale failed to take all reasonable steps to prevent the deaths of two miners last June in Sudbury, Ont.

The 200-page report into the deaths of Jason Chenier and Jordan Fram in Stobie Mine was released Wednesday by the union. It presents evidence that Vale knew there was a problem in the mine before the workers died on June 8.

Chenier, 35, and Fram, 26, were killed by a run of muck, described by the union as an avalanche of wet rocks, gravel and sand.

The union said there was too much water in the muck, making it sticky. It said the muck became lodged in what is known as an ore pass. When Chenier tried to assess the problem, the rock gave way and buried both men.

The report said Chenier wrote an email to management in the days before he died, warning there was a buildup of water in the ore pass and saying all dumping and blasting should stop until the water situation was under control.

"Jason Chenier sent two emails to management warning them of the dangerous water levels, but nothing was done," Local 6500 president Rick Bertrand said. "We don't know why. Management failed to interview with our team."

Steelworkers, during a news conference at the Ontario legislature in Toronto on Wednesday, called for a public inquiry.

The union also asked the attorney general's office to consider criminal charges against company officials, under what is known as the Westray bill. Named after a coal mining disaster in Nova Scotia, the bill makes workplace negligence a criminal offence.

A Vale spokesperson said the union would not provide an advance copy of the report, so the company won't comment until it assesses the union's findings.

However, company spokesperson Angie Robson said in an email that Vale stands "by the results of our own internal investigation — it was thorough, complete and conducted by senior and experienced experts."

"That investigation concluded that there were a number of factors contributing to this tragic incident with no single cause or individual at fault."

MPP wants action

Meanwhile, the investigation into the death of the two miners at Vale's Stobie mine came up at Queen's Park on Wednesday.

Nickel Belt MPP France Gelinas questioned the McGuinty government on whether charges would be laid under the Westray provision of the Criminal Code.

“The tragedy of those two deaths is that the mining companies know how to prevent those incidents from becoming accidents,” Gelinas said. “It's a matter of taking action."

Labour Minister Linda Jeffrey noted the ministry's investigation is continuing.

"It would be inappropriate for me to comment on the specifics of this case,” Jeffrey’s said. “What I can say is that our investigators have been working on this case since day one and their investigation will be thorough and comprehensive."

Jeffrey said the province is committed to improving health and safety in Ontario's mines.

USW Local 6500 Double Fatalities Investigation Report