Engineering firm AMEC says one of its offices was served with a search warrant as part of the investigation into the Mount Polley mine spill.
Lauren Gallagher, a company spokeswoman, wrote in an e-mail that AMEC's office in Prince George, B.C., was the target of the warrant. AMEC is the engineer of record for the Mount Polley tailings dam, the site of the spill last summer. She said the company is co-operating fully with authorities.
B.C.'s Conservation Officer Service, a government agency that focuses on natural resource law enforcement and human-wildlife conflicts, is leading the investigation.
The conservation service earlier this week said it had executed search warrants at the Mount Polley mine and the Vancouver office of its owner, Imperial Metals.
The Globe and Mail has since learned the service executed four search warrants in all. The third was at the AMEC office. The target of the fourth warrant remains unclear.
Chris Doyle, an agency inspector, confirmed on Thursday all four warrants had been executed, but said he could not release further details.
Mr. Doyle said the investigation is ongoing and the agency continues to interview witnesses, among other things.
AMEC took over as engineer of record for the tailings pond from Knight Piésold in 2011.
Ms. Gallagher said the documents sought in the search were virtually identical to the documents AMEC already disclosed to B.C.'s Ministry of Mines and an independent panel that studied the cause of the spill.
The independent panel released its report last week. It said the design of the tailings pond dam failed to address the fact that it sat on an unstable foundation, a flaw that was compounded by raising the dam several times over many years.
In August, 25 million cubic metres of water and mining waste breached the tailings pond and entered Polley Lake and Quesnel Lake. Imperial Metals earlier said it understood the warrants are a normal means of investigation and the company was fully co-operating.
Sabine Goetz, a spokeswoman for Imperial Metals, said on Thursday the company was aware of only the warrants involving its mine and head office. Mr. Doyle has said the investigation primarily focuses on offences under the B.C. Environmental Management Act and the federal Fisheries Act, "but is not limited to these acts."
The conservation service is being assisted by Environment Canada, Fisheries and Oceans Canada and the RCMP.