RE: Grading Hi Newfer, I don't have any background in mining or metallurgy, so I'm dependant on what's written in the recent PEA. Take a look at section 13, on pages 42 & 43, where there's helpful information. I think PLY's plan is run a low-cost micro-operation at Grey River, where they will extract a narrow band of rich ore from the #10 vein, and then process that ore into a commercially valuable WO3 concentrate by using cheap gravity-separation methods. The PEA seems to say the concept is attractive but that there's not been enough metallurgical testing to determine whether PLY's plans will be successful in an actual production scenario.