My SH post:

Osisko's (OSK) Canadian Malartic open-pit mine has the following grades:
1 NI 43-101 Proven and Probable Reserves:
28.4 Mt @ 0.92 g/t Au & 217.4 Mt @ 1.16 g/t Au

2 NI 43-101 Indicated Resource: 70.4 Mt @ 0.99 g/t Au

3 NI 43-101 Inferred Resource: 20.0 Mt @ 0.73 g/t Au

and look where they are.

If PRB can prove up tonnage with the drill, the grades found so far will be more than adequate, IMO.