A worker died on Monday after he was injured by heavy machinery during the demolition of a house in Union County, officials said. The man was on the site of a property on Mountain Avenue around 3:30 p.m. when he was struck by the bucket of a backhoe, the Scotch Plains Police Department said in a news release. He suffered severe head trauma as a result of the incident, authorities said. The man was later pronounced dead at Overlook Medical Center, officials said. His identity is being withheld pending notification of the next of kin. The incident appears to be accidental at this time, according…