Zenyatta Ventures Ltd

"If you'd done your DD the reason they are quoting 660,000 tons in the PEA is because its suitable for open pit"

I have done my DD, however it still doest get to the elephant in the room. There is 977,000 stated in the RE, ALL of it is above the sill. Why is it now 660,000? Certainly willing to hear an expalnation, so far nothing satisfactory.