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(THE CONVERSATION) The Trump administration announced new pollution rules for coal-fired power plantsdesigned to keep existing coal power plants operating more and save American coal mining jobs.

Profitability for U.S. coal power plants has plummeted, and one major coal company after another has filed for bankruptcy, including the world’s largest private-sector coal company, Peabody Energy.

The main reason coal is in decline is less expensive natural gas and renewable energy like s...