Wrong!

Companies who are defining a deposit will talk about a resource footprint being traced over x-strike length, x-width and x-depth. Now we have a three dimensional mass.

The above would give you a volume, not a mass. To get mass, you'd have to multiply by the density of the host rock, would you not? Then you would have a mass. For example @ Tesoro, the volume would be multiplied by approx 2.7T/M3, then you'd have a mass!