A large excavator tumbled into an excavated pit on March 3 during demolition of a county government office building complex in Washington, Pa., southwest of Pittsburgh, but the operator appears to have been unhurt, according to published reports.Detroit-based demolition contractor Adamo Group had begun work on the project the previous day under a $1.55-million county contract awarded last year, which includes demolition of a six-story 1970s office building and adjacent underground garage. The excavator operator was not identified. A video taken from a nearby building posted on a local news site shows the partially obscured excavator working around the garage entrance, then adjusting its position just prior to disappearing from view. Post-incident news photos and video show the excavator lying partially on its side in the pit.…