That's a map of "major" deposits. I'm going to guess that there are either 1) smaller local operations outside of those areas or 2) the economics of transport r

That's a map of "major" deposits. I'm going to guess that there are either 1) smaller local operations outside of those areas or 2) the economics of transport raise the cost of sale significantly in those areas. (or most likely, some combination of 1 & 2)