Ensia: According to a recent report from the U.S. Energy Information Administration, the number of new and reactivated coal mines in the U.S. hit a 10-year low in 2013 -- down nearly 67 percent from 2008.
Total coal production in the U.S. was also down during the same time period. The drop was driven by a number of factors, including regulatory pressure, reduced investment, shifting demand toward natural gas and renewables and weak exports.
Overall, the total number of coal mines in the U.S. also...