To insure public safety when highwalls are retained as part of the intended future use, the operator shall:

(A) Design the procedures to detonate explosives in a manner that the final highwall will not be fractured to an unstable condition;

(B) Stabilize any unstable final highwalls;

(1) Lime mining waste used to backfill highwalls. An angle of eighteen degrees or less, in accordance with paragraph (A) of rule 1501:14-3-06 of the Administrative Code, from the top of the highwall to the quarry floor shall be deemed acceptable with a minimum of four feet of non-toxic earthen material covering the submerged slope, with an additional six inches of topsoil used to cap any exposed slope, then planted to a diverse vegetative cover in accordance with Chapter 1501:14-3 of the Administrative Code. An alternative plan for cover or treatment may be approved by the chief based upon a showing by the applicant that, at a minimum, the alternative plan is as effective as four feet of cover for protecting water quality and sustaining vegetative growth.

(C) Provide egress from the pit area;

(D) Restrict access to the highwall as approached from the top; and

(E) Perform other measures as are necessary to insure public safety because of the particular site conditions.