One Billion Tons?? Net Mineable Quantity?While Billion tons is a lifetime supply, strikes me as a fair amount has to be left behind to support the underground structure.I wonder what that percentage is, and then how that affects the mines value?
Our rock salt mines are located underground, as deep as 1,800 feet below the surface. We extract salt from each mine in rectangular "room" sections, leaving behind vast “pillars” of salt to support the mine structure.