http://www.cnn.com/2017/03/30/opinions/war-on-coal-mining-michaels/index.html
No time to read, but did you perhaps mention another huge liability ???
Health & mortality rates ???
Working in a no window & sunshine zone plus HIGH STP ain’t exactly a rose garden…. I’ll bet those costs factor have a bigger than publicly admitted impact on ROI decisions.
Live~NRGY 
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