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Statement of Need: MSHA issued the ETS in response to the grave danger that miners face when underground seals separating abandoned areas from active workings fail. However, as the ETS is effective until superseded by a mandatory standard, which MSHA shall promulgate within 9 months after publication of the ETS, the ETS provides miners continued critical protection that strengthens the requirement for the design, construction, maintenance, and repair of seals, as well as requirements for sampling, monitoring, and controlling atmospheres behind seals and providing training to miners constructing or repairing seals.

Summary of the Legal Basis: Promulgation of this regulation is authorized by section 101 of the Mine Act and by section 10 of the MINER Act.

Alternatives: This final rule would provide: (1) the safety protections afforded to miners by the existing ETS; and (2) additional protections through experience gained through the rule and comments received during rulemaking. MSHA has analyzed regulatory alternatives in its regulatory economic analysis (REA) in support of the ETS. MSHA prepared any analysis of the cost of two alternatives regarding seal application approval: (1) certification of a professional engineer along with supporting documentation; and (2) design based on actual explosion testing. MSHA also considered and included a discussion of alternatives in the preamble to the ETS without a cost analysis. MSHA requested comments on alternatives including seal design, sampling, construction, and seal strength.

Anticipated Costs and Benefits: The anticipated costs and benefits of the final rule focus on seals that would actively monitored to maintain an inert atmosphere and seals that would be strengthened to better withstand explosions, both of which would reduce injuries and fatalities. MSHA will prepare a regulatory economic analysis for the final rules.

Risks: Underground coal mines are dynamic work environments in which the working conditions can change rapidly. Caved, mined-out areas may contain coal dust and accumulated gas. This gas can be ignited by rock falls, lightning and, in some instances, fires started by spontaneous combustion. Seals are intended to isolate the environment within the sealed area from the active workings of the mine, and to prevent an explosion that may occur on the inby side of the seal from propagating to the outby side of the seal where miners work or travel. Seals must therefore be designed to withstand elevated pressures and also to prevent the sealed atmosphere from reaching the explosive range. Adequate seals are crucial to contain explosions and prevent potentially explosive or toxic gases from migrating into the active working areas of underground coal mines. Miners rely on seals to protect them from the potentially hazardous environments within the sealed area. Recent mine explosions have demonstrated that improvements in seals are needed.