Prime Minister Stephen Harper, who was speaking at the PDAC 2014 convention today, said the weight of the environmental assessment compelled his government to reject the New Prosperity mine proposal.

Last week Environment minister Leona Aglukkaq rejected Taseko Mining's $1.5-billion New Prosperity mine near Williams Lake since it would cause significant adverse environmental effects.

Harper said his government doesn't like to deprive regions of economic opportunities but the report was extremely negative:

I don't know if it is my place to get into the decision in detail. The decisions of this government are largely driven by the rigorous environmental assessments that we have undertaken by scientists, by experts. In the particular case of New Prosperity–this is actually the second go around–the environmental assessment was extremely negative–was extremely negative, particularly with regard to the hydrographic system in the region.

It said very clearly as the project was presently and previously conceived would not address the long term destruction of that system.

Our experts said they could see no proposed possible mitigation for that. So it was a very damming report. It was also in an area–to be frank on this also–where there are unresolved land claim issues.

Harper said the company should read the reasons for the environmental assessment rejection "very carefully" and is welcome to reapply.

Harper was also asked if the Mining Tax Credits could be made permanent. In February the Mineral Exploration Tax Credit was extended until March 2015. The PDAC has been lobbying for permanence stating that the move would create stability.

"I would never pre-judge the actions of the minister of finance," Harper deflected.

Harper is the first sitting Prime Minister to speak at a PDAC convention.