“Excavation” defined

1. “ Excavation ” means the movement or removal of earth, rock or other material in or on the ground by: (a) Use of mechanical equipment; (b) Use of non-mechanical equipment by: (1) A contractor; or (2) Any person, other than a contractor, if at any point the movement or removal of such material occurs more than 12 inches below the surface of the original groundline; or (c) The placement and discharge of explosives. 2. The term includes augering, backfilling, boring, digging, ditching, drilling, grading, plowing-in, ripping, scraping, trenching and tunneling.