Oklahoma Administrative Code
Title 460 - Department of Mines
Chapter 20 - The Permanent Regulations Governing the Coal Reclamation Act of 1979
Subchapter 43 - Permanent Program Performance Standards: Surface Mining Standards
Section 460:20-43-14 - Impoundments

(1) Impoundments meeting the Class B or C criteria for dams in the U.S. Department of Agriculture, Soil Conservation Service Technical Release No. 60 (210-V1-TR60, Oct. 1985), shall comply with "Minimum Emergency Spillway Hydrologic criteria" table in TR-60 and the requirements of this section. The technical release is hereby incorporated by reference. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 5529a) and 1 CFR Part 51. Copies may be obtained from the national technical Information Service (NTIS), 5285 Port royal Road, Springfield, Virginia 22161, order No. PB 87-157509/AS. Copies can be inspected at the OSM headquarters Office, office of Surface Mining Reclamation and Enforcement, administrative Records, Room 660, 800 North Capitol Street, Washington, D.C. or at the Office of the Federal register, 800 North Capitol Street, NW, Suite 700, Washington, D.C.

(2) Impoundments meeting the criteria of 30 CFR Section 77.216 shall comply with the requirements of 30 CFR Section 77.216 and this Section. The plan required to be submitted to the District Manager Of MSHA under 30 CFR Section 77.216 shall also be submitted to the Department as part of the permit application.

(3) Design Certification. The design of impoundments shall be certified in accordance with Section 460:20-27-14(a) of this Chapter as designed to meet the requirement of this Subchapter using current, prudent, engineering practices and any design criteria established by the Department. The qualified, registered, professional engineer or qualified , registered, professional, land surveyor shall be experienced ibn the design and construction of impounds.

(4) Stability.

(5) Freeboard. Impoundments shall have adequate freeboard to resist overtopping by waves and by sudden increases in storage volume. Impoundments meeting the Class B or C criteria for dams in TR-60 shall comply with the freeboard hydrograph criteria in the "Minimum Emergency Spillway Hydrologic Criteria" table in TR-60.

(6) Foundation.

(7) Slope protection shall be provided to protect against surface erosion at the site and protect against sudden drawdown.

(8) Faces of embankments and surrounding areas shall be vegetated, except the faces where water is impounded may be riprapped on otherwise stabilized in accordance with accepted design practices.

(9) Spillways. An impoundment shall include either a combination of principal emergency spillways or a single spillway configured as specified in (a)(9)(A) of this Section, designed and constructed to safety pass the applicable design precipitation event specified in (a)(9)(B) of this Section, except as set forth in (c)(2) of this Section.

(10) The vertical portion of any remaining highwall shall be located far enough below the low-water line along the full extent of highwall to provide adequate safety and access for the proposed water users.

(11) Inspections. Except as provided in (a)(11)(D)of this section, a qualified registered professional engineer or other qualified professional specialist under the direction of a professional engineer, shall inspect each impoundment as provided in (a)(11)(A) of this Section. The professional engineer or specialist shall be experienced in the construction of impoundments.

(12) Impoundments meeting the SCS Class B or C criteria for dams in TR-60 or other criteria of 30 CFR 77.216 must be examined in accordance with 30 CFR 77.216-3. Other impoundments shall be examined at least quarterly by a qualified person designated by the operator for the appearance of structural weakness and other hazardous conditions.

(13) Emergency procedures. If any examination or inspection discloses that a potential hazard exists, the person who examined the impoundment shall promptly inform the Department of the finding and of the emergency procedures formulated for public protection and remedial action. If adequate procedures cannot be formulated or implemented, the Department shall be notified immediately. The Department shall then notify the appropriate agencies that other emergency procedures are required to protect the public.

(14) The embankment slopes of each impoundment shall not be closer than 100 feet, measured horizontally, to any public road right-of-way unless otherwise approved under procedures established in 460:20-7-4(4) and 460:20-7-5(d). The area between the road right-of-way and the impoundment slopes, clear zone slopes, shall not be steeper than a 1V:6H grade.

(1) The size and configuration of such impoundment will be adequate for its intended purposes.

(2) The quality of impounded water will be suitable on a permanent basis for its intended use and, after reclamation, will meet applicable State and Federal water quality standards, and discharges from the impoundment will meet applicable effluent limitations and will not degrade the quality of receiving water below applicable State and Federal water quality standards.

(3) The water level will be sufficiently stable and be capable of supporting the intended use.

(4) Final grading will provide for adequate safety and access for proposed water users.

(5) The impoundment will not result in the diminution of the quality and quantity of water utilized by adjacent or surrounding landowners for agricultural industrial, recreational, or domestic uses.

(6) The impoundment will be suitable for the approved postmining landuse.

(1) The Department may authorize the construction of temporary impoundments as part of a surface coal mining operation.

(2) In lieu of meeting the requirements of (a)(9)(A) of this Section, the Department may approve an impoundment that relies primarily on storage to control the runoff from the design precipitation event when it is demonstrated by the operator and certified by a qualified registered professional engineer or qualified registered land surveyor in accordance with Section 460:20-27-14(a) of this Chapter that the impoundment will safely control the design precipitation event, the water from which shall be safely removed in accordance with current, prudent, engineering practices. Such an impoundment shall be located where failure would not be expected to cause loss of life or serious property damage, except where: