NEW JOHNSONVILLE, Tennessee, Aug. 2 -- The Tennessee Valley Authority issued the following news release: With a boom and a cloud of dust, the Tennessee Valley Authority imploded the 600-foot smokestack of its oldest coal-fired power plant, located in New Johnsonville, Tennessee. The implosion clears the site for future development and a possible generation project that could advance clean-energy technologies. "I'm sad to see it go," said Bob Joiner, a TVA retiree who worked at the plant for mo  more