In addition to being plugged in accordance with the laws of the State of California, every such oil well and the space between the surface casing and any water string which is not removed from the well shall be filled with a good grade rotary mud weighing not less than 70 pounds per cubic foot. Filling shall begin at the uppermost sealing plug required by laws or regulations of the State of California and shall be capped with at least 100 lineal feet of cement downward from the floor level of the cellar but not less than 6 feet below grade. Such cement cap shall be inside the casing and the water string and shall be covered at the cellar floor level by a steel plate of the same thickness and with the same inside diameter as the casing. Such plate shall be welded throughout its entire circumference to the casing with at least three welding passes and the Los Angeles Fire Department number of the oil well shall be arc welded on the plate using non-corrosive welding rod. All such welding shall be performed by a certified welder. Cement caps shall be composed of one part cement to not more than two and one-half parts sand and not more than three and one half parts gravel or crushed rock. The derricks, including all derrick parts, shall be dismantled and removed from the premises immediately after the well hole has been plugged and sealed.
EXCEPTION: Neat cement may be used for the surface plug when installed by an approved cementing company.