Davin, Chris and I were up there a couple of years ago. Looked like lots of good country, and some mines in the area. If I remember right, there was some sort of greenstone belt that ran through there. We went up to look at an old gold prospect called, I think, the Poland-China mine. It's near Chelsaw, more toward the central part of northern WA. When we got there, there were geologists already drilling it for new deposits. I did notice, on Google Earth, what looked like possible kimberlite pipes, too. When I mentioned that to the old guy that had asked me to look at it, he said there were stories of diamonds being found there. The geologists told me there were platinum deposits farther east along the WA/Can border, too.
If you prospect northeastern WA, be sure and keep an eye on your pan for gems.
Jim