VANCOUVER -- The federal government's decision to reject a proposed $1.5-billion gold-copper mine in British Columbia has caused a stir in the Conservatives' own caucus and an outcry from supporters of the project.

B.C. Conservative MPs Dick Harris and Cathy McLeod both openly questioned the decision to reject the mine proposed by Taseko Mines Ltd. (TSX:TKO) over environmental concerns.

Harris, a longtime MP first elected under the Reform banner in 1993, said Thursday the decision has shattered the hopes of thousands of people in the Cariboo-Chilcotin region.

He said that in the economically depressed area, supporting the New Prosperity Gold Copper Mine was a responsible move for many people who have been forced to leave their hometown to find work elsewhere.

"Taseko mine was their ticket to come back," Harris, whose riding is north of the proposed project site, in a phone interview.

"The Taseko project was going to allow them to be trained and skilled and employed in a good-paying, 25- to 30-year job in the mine just right out in the area where they live. And this is gone now as a result of the decision."

Harris added that he considered the rejection a personal failure, as he and others had worked so hard to make the project happen.

McLeod, who represents the Kamloops-Thompson-Cariboo riding that incorporates the mine site, called the decision a huge blow to the Cariboo region.

"There are tens of thousands of people in the Cariboo who were looking at this project as a lifeline and an opportunity in communities that have been very hard-hit," she said.

"I really am feeling incredibly disappointed and I know the people in the Cariboo, many, many are phoning and they're very upset about the decision."

The site is 125 kilometres southwest of Williams Lake, B.C., and is the tenth- largest undeveloped gold-copper deposit in the world.

Environment Minister Leona Aglukkaq announced Wednesday evening that she had rejected the mine because it would have significant adverse environmental effects that cannot be mitigated.

It is the second time the federal government has said no. A similar proposal by Taseko was rejected four years ago because the plan was to drain a lake for use as a tailings pond.

The revised proposal preserved the lake but a federal environmental review panel found the mine would still cause significant adverse effects on water quality, fish and fish habitat in the lake important to local First Nations.

"The government of Canada will make decisions based on the best available scientific evidence while balancing economic and environmental considerations," Aglukkaq said in a news release.

"The government will continue to make responsible resource development a priority and invites the submission of another proposal that addresses the government's concerns."

Taseko has applied to the Federal Court for a judicial review of the assessment, arguing the panel used the wrong information in drawing its conclusions.

Brian Battison, vice-president of corporate affairs at Taseko, accused the federal government of turning its back on British Columbians.

"Some are going to say the government of Canada has abandoned their stated priorities of creating jobs and growth and lasting prosperity of resource development," he said in a phone interview following the announcement.

"And some are going to say the government of Canada has snatched away the hope from First Nations, the hope that they had for a better future of new jobs and opportunities closer to where they live."

But First Nations who oppose the mine are celebrating its rejection. Tsilhqot'in Tribal Chairman Joe Alphonse predicted that the mine is dead, and Assembly of First Nations National Chief Shawn A-in-chut Atleo applauded the federal government for not caving in to pressure from industry.

"We commend the Minister and the federal government for making the right decision that is symbolic of a path forward right across this country -- respecting Indigenous rights and title, respecting environmental concerns and clearing away barriers to building respectful and sustainable approaches to community and economic development," Atleo said in a written statement.