Taseko's first proposal was rejected November 2, 2010 by then Environmental Affairs Minister Jim Prentice. Public and First Nations concerns over impacts of mining operations on Fish Lake continue. A federal review panel found the proposed mine would cause irreparable damage to both First Nations rights and the environment, including to fish stocks and grizzly populations. The company submitted a revised proposal August 9, 2011, which was accepted by the Canadian Environmental Assessment Agency November 7, 2011.

Taseko Mines filed a Notice of Civil Claim against the Western Canada Wilderness Committee March 1st, accusing the Wilderness Committee and its outreach director Sven Biggs for "a series of false and defamatory statements concerning Taseko and its proposed New Prosperity Gold-Copper Project."

The Wilderness Committee has vowed to fight the civil claim.

"This ill-conceived mine proposal should be turned down once and for all. That's our view and we're standing by it. We believe this court action stifles fair comment about Taseko's environmentally risky mine proposal. People should be able to enjoy full participation in the Federal Environmental Review process, including the right to comment – without fear of time-consuming and costly litigation," said Joe Foy, national campaign director for the Wilderness Committee.