High grade starter pitThe PEA indicated mining rate of 3,400,000 t/yr x average grade (17.5% C) x recovery (85%) = 510,000 t/yr of concentrate. This appears to be the number they used in their PEA which provided an after-tax IRR of 26% (after-tax payback of 3.2 years).
However, Lac Gueret has a higher-grade core zone, grading 28% C, which is what Mason originally planned their smaller scale mining operation on. Assuming this zone will be the starter pit, production in the early years will be 510,000 (28/17.5) = 816,000 tC/yr. The after tax IRR will thus increase to 26% x (28/17.5) = 42% and payback will reduce to 2 years. Presumably the analysts will be going over these underlying assumptions and opportunities over the next few days.