Testimony concludes in Sudbury mining accident inquest

Testimony in the coroner's inquest into the death of Paul Rochette wrapped up in Sudbury on Wednesday.

Rochette died at Vale's Copper Cliff Smelter in 2014 while trying to remove a metal object stuck in an ore crusher.

Cynthia Matikainen, a mechanical engineer with the Ministry of Labour, testified that a build-up of stored energy in the ore crusher led to Rochette's death.

On Tuesday, the court heard evidence Rochette had tried to remove the piece of metal called a moil point with a torch. The moil had become jammed in the crusher during the previous shift.

Matikainen explained to the court that the jam effectively turned the machine into a giant spring.

She said when the metal object was heated and softened by the torch, the friction that held it in place was suddenly reduced. That caused the crusher to spring back, propelling the 118 lb piece of metal from the machine.

Rochette suffered a massive blunt impact head injury and was killed. Justin Stewart, the only other worker at the site, sustained serious injuries as well.

Vale, union led internal investigation

Worker safety representative Jamie West testified that an investigation led by the union and Vale also identified stored energy as an underlying cause of the incident.

But previous testimony from workers and supervisors at the smelter revealed little training on stored energy, or other risks associated with crushers.

Gord Gilpin, who was the smelter's maintenance manager at the time of the incident, said the investigation did lead to 58 safety recommendations.

Some of those recommendations included a defined procedure for dealing with a stalled crusher, and a specific training module on crushers.

The jury is expected to deliberate following final submissions on Thursday, and will consider recommendations to help prevent similar incidents from happening in the future.