Okla. Admin. Code § 460:20-43-30
(a) Refuse piles shall meet the requirements of Section 460:20-43-29, the additional requirements of this Section, and the requirements of 30 CFR 77.214 and 77.215.
(1) Drainage control.
(c) Placement.
(d) Inspections. A qualified registered professional engineer, or other qualified professional specialist under the direction of the professional engineer, shall inspect the refuse pile during construction. The professional engineer or specialist shall be experienced in the construction of similar earth and waste structures.
(1) Such inspections shall be made at least quarterly throughout construction and during critical construction periods. Critical construction periods shall include at a minimum: