An investigation report by the Chief Inspector of Mines is not recommending charges against Mount Polley Mine for the Aug. 4, 2014 tailings impoundment breach.
“During our 15-month investigation into the breach we found no non-compliance with mines act permits or regulations,” said Chief Inspector of Mines Al Hoffman Thursday during a media conference. “Although there were poor practices by the company there were no offences we could find.”
Energy and Mines Minister Bill Bennett said a series of dominoes led to the failure.
“The unstable and unknown glaco-lacustrine level underneath the dam, the over steep slopes, lack of beaches inside the tailings impoundment, too much water and excavation outside the mine left there for eight months all led to the failure,” Bennett said.
There is still an ongoing investigation by the Conservation Officer Service and there may be the possibility of prosecution there, both Hoffman and Bennett said.
When asked how he felt about the event happening under his watch, Hoffman said it was the most difficult thing he has dealt with.
“Now I feel very strongly that we have recommendations going forward that we can to a large extent prevent this from happening again,” Hoffman said.
Bennett said in the report there are incidents of ministry of energy and mines staff asking all the right questions and the engineer of record responding that everything was OK.
“The accident at Mount Polley is an anomaly and not what ordinarily happens in B.C.” Bennett said. “I think there is a real need now that we are responding to examine how much we rely on best practices and guidelines that are established outside the regulator’s domain.”
There has to be more of a cushion in terms of the level of risk as there was when the “terrible and inexcusable accident happened,” he added.
The report is recommending all mines with TSFs be required to have a designated mine dam safety manager and a designated individual to oversee the mine’s water balance and water management plan.
Mines with TSFs will be required to have water management plans designed by a qualified professional and an independent technical review board will be required for all mines with TSFs.