Texas Administrative Code › Title 16 - ECONOMIC REGULATION › Part 1 - RAILROAD COMMISSION OF TEXAS › Chapter 12 - COAL MINING REGULATIONS › Subchapter K - PERMANENT PROGRAM PERFORMANCE STANDARDS › Division 3 - PERMANENT PROGRAM PERFORMANCE STANDARDS - UNDERGROUND MINING ACTIVITIES › Section 12.533 - Disposal of Underground Development Waste and Excess Spoil: Head-of-Hollow Fills

Current through Reg. 49, No. 28; July 12, 2024
Disposal of underground development waste and excess
						spoil in the head-of-hollow fill shall meet all standards set forth in §
											RSA
						12.531 and §
											RSA
						12.532 of this title (relating to Disposal of
						Underground Development Waste and Excess Spoil: General Requirements, and to
						Disposal of Underground Development Waste and Excess Spoil: Valley Fills) and
						the additional requirements of this section.
(1) The fill shall be designed to completely
					 fill the disposal site to the approximate elevation of the ridgeline. A
					 rock-core chimney drain may be utilized instead of the subdrain and surface
					 diversion system required for valley fills. If the crest of the fill is not
					 approximately at the same elevation as the low point of the adjacent ridgeline,
					 the fill must be designed as specified in §
											RSA
					 12.532 of this title (relating to Disposal of
					 Underground Development Waste and Excess Spoil: Valley Fills), with diversion
					 of runoff around the fill.
(2) The
					 alternative rock-core chimney drain system shall be designed and incorporated
					 into the construction of head-of-hollow fills as follows:
(A) the fill shall have, along the vertical
					 projection of the main buried stream channel or rill, a vertical core of
					 durable rock at least 16 feet thick which shall extend from the toe of the fill
					 to the head of the fill, and from the base of the fill to the surface of the
					 fill. A system of lateral rock underdrains shall connect this rock core to each
					 area of potential drainage or seepage in the disposal area. Rocks used in the
					 rock core and underdrains shall meet the requirements of §
												RSA
					 12.532<subdiv>(2)</subdiv> of
					 this title (relating to Disposal of Underground Development Waste and Excess
					 Spoil: Valley Fills);
(B) a filter
					 system to ensure the proper functioning of the rock core shall be designed and
					 constructed using standard geotechnical engineering methods; and
(C) the grading may drain surface water away
					 from the outslope of the fill and toward the rock core. The maximum slope of
					 the top of the fill shall be 33h:1v (3%). Instead of the requirements of §
												RSA
					 12.531<subdiv>(g)</subdiv> of
					 this title (relating to Disposal of Underground Development Waste and Excess
					 Spoil: General Requirements), a drainage pocket may be maintained at the head
					 of the fill during and after construction, to intercept surface runoff and
					 discharge the runoff through or over the rock drain, if stability of the fill
					 is not impaired. In no case shall this pocket or sump have a potential for
					 impounding more than 10,000 cubic feet of water. Terraces on the fill shall be
					 graded with a 3% to 5% grade toward the fill and a 1% slope toward the rock
					 core.