Workers from Gwenmor Marine on Tuesday begin to remove a large rotting coal barge that for decades has been part of the Route 27 landscape behind Twisters Ice Cream on the Mystic River. The project is being done thanks to Clean Up Sound and Harbors, which raised the approximately $10,000 for the removal. Mystic River Harbormaster Paul Watts said the barge had remained intact for many years but more recently started breaking apart, sending debris into residents’ yards and posing a hazard to boats. “I really want to see this thing gone. It’s been on our books to do for years and it’s now coming together with the help of CUSH,” he said. CUSH received permits for the work from the state Department of Energy and Environmental Protection and the U.S. Army Corps of Engineers.