Md. Code Regs. 26.20.27.04

Current through Register Vol. 51, No. 21, October 18, 2024

Section 26.20.27.04 - Construction Requirements

A. Refuse piles shall be constructed in compliance with the requirements of COMAR 26.20.26, except to the extent that the requirements of that chapter are varied in this regulation.

B. Refuse piles shall have a minimum static safety factor of 1.5.

C. Compaction requirements during construction or modification of all coal mine waste disposal facilities are as follows:

(1) Waste shall be spread in layers not more than 24 inches in thickness.

(2) Waste shall be compacted to attain 90 percent of the maximum dry density to prevent spontaneous combustion and to provide the strength required for stability of the coal processing waste bank. Dry densities shall be determined in accordance with the American Association of State Highway and Transportation Officials (AASHTO) Specification T99-74 (Twelfth Edition) (July, 1978), or an equivalent method.

D. Following final grading of the coal mine waste disposal facility, the site shall be covered with a minimum of 4 feet of the best available nontoxic and noncombustible material in a manner that does not impede flow from subdrainage systems and shall be revegetated. The Bureau may allow less than 4 feet of cover material based on physical and chemical analyses which show that the revegetation requirements will be satisfied.

E. Permanent impoundments may not be allowed on completed refuse piles.

F. The final configuration of refuse piles shall be suitable for the approved postmining land use. Terraces may be constructed on the outslope if required for stability, control of erosion, conservation of soil moisture, or facilitation of the approved postmining land use. The grade of the outslope between terrace benches may not be steeper than 2h:1v (50 percent).

Md. Code Regs. 26.20.27.04

Regulations .04 were previously codified as COMAR 08.13.09.33 a A_K, respectively. Recodification occurred in April, 1993. For a history of these regulations before April, 1993, see "Administrative History of COMAR 08.13.09 before April, 1993" which follows COMAR 26.20.01.