http://www.sott.net/article/292524-The-giant-salt-mine-1200-feet-beneath-Detroit-Michigan#comment123607 Comment: The estimates of salt deposits in Michigan are astronomical. Geological studies estimate that 55 counties of the Lower Peninsula cover 30,000 trillion tons of salt. But like much of Michigan’s mineral wealth, only a fraction of this salt can be economically recovered.   Please explain how 30,000 trillion tons of salt can form […]