The method of mining followed in any coal mine shall not expose the miner to unusual dangers from roof falls caused by excessive widths of rooms and entries or faulty pillar recovery methods.
(A) The method of mining shall provide widths of openings and pillar dimensions compatible with effective roof control. These widths and dimensions shall be incorporated into the roof control plan submitted for approval.
Where excessive widths result from poor mining practices, additional roof support shall be installed before any travel or other work is done in such area. If excessive widths of openings are a result of coal sloughing, additional support shall be installed and the mining system reevaluated to determine changes that are necessary to minimize such occurrences.
(1) The overall pillar recovery system shall be designed to minimize the possibility of outbursts or squeezes. The manner and sequence of recovery shall be included in the roof control plan submitted for approval.
(2) Where full pillar recovery is being done, extraction shall be such as to allow total caving of the main roof in the pillared area.
(3) During partial pillar recovery sufficient coal shall be left in place to support the main roof to the extent that the possibility of undue forces overriding the working places will be minimized.
(4) A combination of full and partial pillar recovery shall not be conducted on the same pillar line.
(5) If full extraction of pillars is being done and physical conditions such as standing water, adverse roof conditions, and falls of roof, or law requirements concerning oil and gas wells or surface subsidence dictate that some pillars of coal are to be left in place, a sufficient amount of coal shall be left to support the main roof so as to minimize the possibility of undue forces overriding the working places.
(6) Where full recovery of pillars is planned, the design of the pillars shall be compatible with the planned method of extraction.
(7) Pillaring methods shall eliminate pillar points and pillars that project inby the breakline.
(8) When recovering adjacent pillars left and right from the same opening, mining shall be completed in one such pillar left and the openings posted off with at least two rows of breaker posts on not more than four foot centers before operations are started in the second pillar.
(C) Longwall mining shall be considered as modification of the open-end method of pillar extraction and the support system for the longwall shall be approved on an individual basis.
(D) No person shall refuse or neglect to comply with this section.
Effective Date: 10-29-1995 .