After public pressure, Chicago will shut two aging coal-fired power plants, and the owner of one of the power plants, Midwest Generation, may shut its other four coal plants in Illinois. Since the start of 2010, more than 100 coal plants have been slated for early retirement.

A major reason for coal plants shutting has been public opposition to pollution from coal. Also, looming requirements by the U.S. Environmental Protection Agency (EPA) for stringent pollution controls could take a toll on the coal industry, while boosting the market for pollution control devices. One huge coal plant in New Mexico lost a legal battle with the EPA to avoid having to install a more effective type of pollution-control equipment.

But what really has the coal industry