PURPOSE: This rule complies with section 444.535.1(6), RSMo by setting forth the requirements for use of waste materials in the construction of dams or embankments.

PUBLISHER’S NOTE: The secretary of state has determined that the publication of the entire text of the material which is incorporated by reference as a portion of this rule would be unduly cumbersome or expensive. Therefore, the material which is so incorporated is on file with the agency who filed this rule, and with the Office of the Secretary of State. Any interested person may view this material at either agency’s headquarters or the same will be made available at the Office of the Secretary of State at a cost not to exceed actual cost of copy reproduction. The entire text of the rule is printed here. This note refers only to the incorporated by reference material.

1. (1) General.

   1. (A) No waste material shall be used in the new dams unless approved in the reclamation plan.
   2. (B) The operator shall design, locate, construct, operate, maintain, modify and abandon or remove all dams (used either temporarily or permanently) constructed of waste materials in accordance with the requirements of this rule.

2. (2) Construction of Dams.

   1. (A) Waste shall not be used in the construction of dams unless demonstrated through appropriate engineering analysis to have no adverse effect on stability.
   2. (B) Plans for dams subject to this section shall be approved in the reclamation plan before construction and shall contain the minimum plan requirements established pursuant to 30 CFR Section 77.216-2.

   3. (C) Construction requirements are as follows:

      1. 1. Design shall be based on the flood

from the probable maximum precipitation event unless the operator shows that the failure of the impounding structure would not cause loss of life or severely damage property or the environment, in which case, depending on site conditions a design based on a precipitation event of no less than one hundred (100)-year frequency may be approved in the reclamation plan;

1. 2. The design freeboard distance

between the lowest point on the embankment crest and the maximum water elevation shall be at least three feet (3') to avoid overtopping by wind and wave action;

1. 3. Dams shall have minimum safety fac-

tors as follows: Minimum Loading Safety Case Conditions Factor I End of construction 1.3 II Partial pool with steady 1.5 seepage saturation III Steady seepage from 1.5 spillway or decant crest IV Earthquake (cases II and 1.0 III with seismic loading)

1. 4. The dam, foundation and abutments

shall be stable under all conditions of construction and operation of the impoundment. Sufficient foundation investigations and laboratory testing shall be performed to determine the factors of safety of the dam for all loading conditions in paragraph (2)(C)3. of this rule and for all increments of construction;

1. 5. Seepage through the dam, foundation

and abutments shall be controlled to prevent excessive uplift pressures, internal erosion, sloughing, removal of material by solution or erosion of material by loss into cracks, joints and cavities. This may require the use of impervious blankets, pervious drainage zones or blankets, toe drains, relief wells or dental concreting of jointed rock surface in contact with embankment materials;

1. 6. Allowances shall be made for settle-

ment of the dams and the foundation so that the freeboard will be maintained;

1. 7. Impoundments created by dams of

waste materials shall be subject to a minimum drawdown criteria that allows the facility to be evacuated by spillways or decants of ninety percent (90%) of the volume of water stored during the design precipitation event within ten (10) days;

1. 8. During construction of dams subject

to this section, the structures shall be periodically inspected by a registered professional engineer to ensure construction according to the approved design. On completion of construction, the structure shall be certified by a registered professional engineer experienced in the field of dam construction as having been constructed in accordance with accepted professional practice and the approved design; and

1. 9. A permanent identification marker, at

least six feet (6') high and that shows the dam number assigned pursuant to 30 CFR Section 77.216-1 and the name of the person operating or controlling the dam, shall be located on or immediately adjacent to each dam within thirty (30) days of certification of design pursuant to this rule.

1. (D) All dams, including those not meeting the size or other criteria of 30 CFR Section 77.216(a) shall be routinely inspected by a registered professional engineer or someone under supervision of a registered professional engineer, in accordance with 30 CFR Section 77.216-3.
2. (E) All Dams Shall be Routinely Maintained. Vegetative growth shall be cut where necessary to facilitate inspection and repairs. Ditches and spillways shall be cleaned. Any combustible materials present on the surface, other than that used for surface stability, such as mulch or dry vegetation, shall be removed and any other appropriate maintenance procedures followed.
3. (F) All dams subject to this section shall be certified annually as having been constructed and modified in accordance with current prudent engineering practices to minimize the possibility of failures. Any changes in the geometry of the impounding structure shall be highlighted and included in the annual certification report. These certifications shall include a report on existing and required monitoring procedures and instrumentation, the average and maximum depths and elevations of any impounded waters over the past year, existing storage capacity of impounding structures, any fires occurring in the material over the past year and any other aspects of the structures affecting their stability.
4. (G) Any enlargements, reductions in size, reconstruction or other modification of the dams shall be approved by the commission before construction begins.
5. (H) All dams shall be removed and the disturbed areas regraded, revegetated and stabilized before the release of bond unless retention of those dams are approved as being compatible with an approved postmining land use under 10 CSR 40-2.030.

AUTHORITY: section 444.535.1(6), RSMo 1986.* Original rule filed July 13, 1978, effective Jan. 13, 1979. *Original authority: 444.535, RSMo 1978, amended 1988.