VICTORIA — A government-ordered report says a tailings spill at a B.C. mine was caused by an inadequately designed dam that caused its foundation to fail.
The tailings dam at the Mount Polley mine burst last August, sending 24 million cubic metres of mine silt and water gushing into nearby rivers and lakes.
Norbert Morgenstern, chairman of the panel that investigated the spill, says evidence indicates there was a glacial lake deposit under the foundation of the dam.
The report says the dam’s design didn’t take into account the glacial environment, causing the foundation to fail when it was subjected to heavy stress.
Morgenstern says there were no warning signs that could have foreshadowed the dam’s failure.
The provincial government appointed a panel of three geotechnical experts to investigate the cause of the collapse and the role of government regulation and oversight.