Wherever the word “rock” appears in these specifications, it shall be interpreted to mean any material geologically in place and of a hardness which corresponds to the hardness of the transparent variety of calcite. Other materials shall not be classed as rock, although it may be more economical to remove the same by blasting. Boulders will not be classified as rock unless they are equal to or larger than one cubic yard.
Should rock be encountered in the excavation, it shall be removed by blasting or otherwise. Where blasts are made, the excavation shall be carefully covered with suitable brush, timber or matting to prevent danger to life and property. The contractor shall secure all permits required by law for blasting operations and any additional hazard insurance required; the cost of such permits and insurance to be borne by the contractor. The contractor shall strip the rock of overburden, such stripping to be done in sections. No blasting shall be done by the contractor until he or she has notified the Engineer.
Materials classified as rock in these specifications, if encountered, shall be excavated to not less than three inches below the grade of the bottom of structures and six inches below the bottom of pipes or conduit to be installed, unless specifically shown on the drawings to be removed to a greater depth. After such rock is removed, the excavation shall be backfilled with sand or gravel acceptable to the Engineer and consolidated to place the top surface at the grade established on the drawings for the bottom of the structure, pipe or conduit.
(Ord. 352. Passed 10-22-62.)