Trackhoe op. called supervisor to exchange trackhoe. Supv walked new trackhoe to the cut. Supv parked new trackhoe beside trackhoe that was in production. Supv was attempting to walk trackhoe off cut & moved tracks in wrong position. Machine walked off 8' cut & overturned trackhoe as a result. Supv slammed rt shoulder in cab w/seatbelt on, breaking shoulder socket.