Well, I just found this thread right now
I work in the mining industry (though more at the supply end of stuff)
Try the following consultant firms:
Hatch Engineering
SNC Lavalin (They do quite a few mines each year)
AMEC Americas Ltd.
BHP Billiton (though they are in Montreal IIRC)
I'll go update this post with more names when I get into the office on monday and look up some files
