EE WAS ASSISTING IN PLACING A PIPE TO BE WELDED HE PLACED 1 END ON THE BACK OF A D-3 DOZER & THEOTHER END WAS HELD ON AN EXCAVATOR. EXCAVATOR OPERATOR WENT TO HELP EE & WHEN HE STOOD HIS KNE E HIT A CONTROL WHICH CAUSED THE BOOM TO MOVE. THIS MOVED THE PIPE, WHICH CRUSHED EE'S RIGHT HAND & FINGER BETWEEN THE PIPE & CLAMP