The Canadian Environmental Assessment Agency detailed its complaint in a report earlier this month dealing with Taseko's controversial, $1.1 billion mine proposal near Williams Lake.
"The draft EIS does not meet the requirements of the EIS guidelines," said the July 6 report. "There is substantial information missing from this draft EIS. The quality of all figures in the draft EIS is very poor."
Williams Lake-area First Nations immediately seized on the report, saying the critical response from the federal agency confirms their view that the proposed project should be rejected.
Tsilhqot’in Nation Tribal Chief Joe Alphonse said in a statement First Nations have known from the start the mine could not work.
"They should be embarrassed that they handed in a document like this," the statement said. "They are making a mockery out of the entire environmental assessment process, as well as all other mining companies."
The mine has a controversial history.
The proposal mine was approved by the B.C. government but then rejected after a federal government environmental review in 2010.
Late last year, Ottawa agreed to hear a second environmental review after Taseko reworked the project.
The company said it would spend an extra $300 million to address environmental concerns and promised to save Fish Lake, which band members say is culturally significant to them. Taseko's original proposal involved draining Fish Lake and using it for a tailings pond.
Taseko vice-president Brian Battison said the company doesn't see the Canadian Environmental Assessment Agency's complaints about its draft impact statement as a complete rejection of the mine's environmental plan.
Battison said the company's statement was a draft that was meant to elicit feedback from the federal agency. Battison said Taseko will answer the agency's questions when it files its final environmental impact statement within weeks.
"It was never meant to be complete," said Battison.
"It was intended to provide an indication to CEAA, as they requested, on the direction we were going so they could provide us with comment and observations so that we could take those comments and observations and consider those suggestions in the final document."
Battison said he expects Ottawa to make a decision on the mine by the end of the year or early next year.
Federal Environment Minister Peter Kent's press secretary Adam Sweet issued a statement on the federal report.
"Our government has always insisted on environmental reviews that are thorough, rigorous and completed in a timely fashion," the statement said. "These reviews involve regular back-and-forth between the Canadian Environmental Assessment Agency and project proponents."
"As Taseko learned the first time around, our government will only approve projects that are deemed environmentally sound," the statement said.
The agency's report said Taseko's draft didn't address fundamental issues central to environmental assessment, such as water quality and fish habitat.
The report said when it comes to the proposed mine's use of waterways, the draft "lacks specifics and detail sufficient to assess the adverse environmental impacts that may be caused."
The federal agency said the final draft must also provide more detail on aboriginal issues connected to the proposed mine.
"The draft EIS has not addressed all previously identified potential impacts to aboriginal potential and established rights and conclusions and therefore does not include adequate information as requested by the EIS guidelines," said the report.
Xeni Gwet'in Chief Marilyn Baptiste also used the report to condemn the mine proposal.
"It is an insult to all involved that the company would present such a poorly developed and researched partial document," said Baptiste.