Bloomberg: Coal use in the U.S. will continue to fall though the slide will be gradual as electric utilities switch to cleaner alternatives over years and years, billionaire Warren Buffett said at an event in Indiana this week. Coal will gradually decline in importance, and of course when natural gas prices get low enough you have a big switch over, Buffett said July 22, according to a recording posted online by WFYI, a public radio station in Indianapolis. Coal plants are producing about 38 percent of...