Taseko Mines (TSX:TKO) is firing back at the Canadian Environmental Assessment Agency (CEAA), saying it overstepped its authority when it issued what amounts to a cease-and-desist order on geotechnical work permitted by the province on its New Prosperity mine.

It is also questioning the federal agency’s timing and motivations in issuing the order, since the CEAA was aware of the drilling permit application since February, but said nothing until just three days before the Tsilhqot’in First Nation planned to be in court seeking an injunction.

The company also suggests that all mineral exploration in Canada could be at risk, since the CEAA seems to be suggesting that even the most preliminary types of exploration activity would need a full federal environmental review before work could begin.

The company’s proposed New Prosperity gold-copper mine has a provincial environmental certificate, but not a federal certificate from the CEAA, which has twice rejected the mine.

On July 17, the Tsilhqot’in First Nation – which opposes the mine – received notice that the Ministry of Energy and Mines had issued a drilling permit to the company to carry out geotechnical work – work that is required as part of the provincial environmental certificate.

On Friday, July 28, just three days before the Tsilhqot’in planned to file for an injunction, Taseko received a notice from the CEAA stating that any drilling would be a violation of federal environmental laws.

The company has responded in writing, stating that the section of the Environmental Assessment Act cited by the CEAA applies to mine activities, not exploration activities.

The section of the act cited by the CEAA relates to the “construction, operation, decommissioning and abandonment of a mine”, Taseko says – not exploratory activities that are required prior to a mine being built.

Taseko points out that the drilling permit is it received from the provincial government is for geotechnical work: test pits and monitoring wells “which will generate data” required as part of the provincial environmental certificate.

“None of the work involves the construction or operation of a mine,” the company writes.

If the CEAA’s interpretation of the act were to stand up, “it would result in absurd and unconstitutional effects,” Taseko argues.

Before a proposed mine can even get to an environmental review, a significant amount of geotechnical work must be done first to provide the necessary data needed to assess the project’s viability.

If the CEAA interpretation of the act stands up, it would mean provincial governments would not be allowed to permit exploratory activity, the company argues.

“It would arguably prevent any mineral exploration in Canada unless and until a federal EA had been completed,” the company writes.

Except in Taseko’s case, a federal environmental review has already been conducted twice, and in both cases the proposed mine was refused a certificate.

The company says it is troubling that the CEAA was aware of the drilling permit application Taseko made to the Ministry of Energy and Mines since February, but said nothing until July 28.

“It is troubling that the agency would wait some six months, until the Friday immediately before an injunction hearing seeking to enjoin Taseko from commencing work under the Notice of Work Permit begins, to express for the first time its position that CEAA 2012 prohibits the activities, ” the company writes.

The Tsilhqot’in’s application for an injunction is to be heard today.

nbennett@biv.com