Mechanical means may be used, as necessary, for initial penetration and removal of pavement or other materials requiring use of mechanical means of excavation and then only to the depth of the pavement or other materials. For parallel type excavations within the tolerance zone, the existing facility shall be visually identified at intervals not to exceed fifty feet along the line of excavation to avoid damages. The excavator shall exercise due care at all times to protect the facilities when exposing these facilities;
S.C. Code § 58-36-60