The United Steelworkers Union says the premier has rejected its request for an inquiry into mine safety.
The union started to push for an inquiry into mine safety after the deaths of two men at Vale's Stobie mine in Sudbury in 2011, but the Ministry of Labour said it has already taken many steps to improve mine safety in the province.
Minister Yasir Naqvi said a council was struck in 2010 to make proactive suggestions on workplace safety — and one of its members is a mining subcontractor.
"We should not be getting involved and engaged only after an unfortunate incident takes place," he said.
"We need to make sure we are at the front end, making sure all the precautions are taking place, and everybody is trained."
As for safety measures, Naqvi pointed to the introduction of six new mining regulations in the past 10 years.
And there have been 10 mining safety blitzes since 2008, he said.
However the United Steelworkers continue to argue the deaths of Jordan Fram and Jason Chenier — Sudbury miners who died June 8, 2011, after those programs rolled out — were preventable.
Staff representative Miles Sullivan said recommendations from a coroner's inquiry into a mining death 15 years ago would have prevented the deaths — if they had been acted upon.
"Yes, there can be blitzes and there can be things like that," he said. "Obviously they're falling short of what's required [and] fatalities are still happening. They shouldn't continue to be happening."
Sullivan said the union will continue to push for an inquiry into mines safety.
"We think an inquiry is a quick way and an effective way and the best way to look at why fatalities continue to happen in Ontario mines," he said.
"And how to put in safeguards and better practices to make sure that every worker who goes to the mine returns home safely at the end of the shift."