RE:RE:Vertical Gold - Mind Blowing! I think your calculation is based on a bad assumption. Your result that they'll be mining an average of 40 oz per ton doesn't make sense given that they have never released even a single assay even a quarter that high. Sorry to burst any bubbles.
I believe your error is in interpreting the length of the zone. 1200 oz per vertical meter to me means if the mined width is 3 meters, and the length of the zone is 100 (for instance) meters, a vertical meter would contain 300 cubic meters, or 900 tonnes. Both of the width and length here are just for illustration. I haven't done the research to make a reasonable guess at what they actually are, but your result is clearly wrong, and those dimensions are likely the source of the error.