Recent Mine-Seal Issues Observed By The Mine Safety & Health Administration (MSHA)

Since the promulgation of the Mine Safety and Heath Administration?s (MSHA?s) Final Rule on mine seals (30 CFR § 75.335(b)), which became effective on October 20, 2008, many seal designs have been approved by MSHA and constructed by the mining industry. Since the effective date of the Final Rule, several issues on the design, construction, and/or inspection of seals have been brought to the attention of MSHA. Several such issues discussed in this paper include; the directional, design-load criteria required by MSHA for 50-psi seals, 120-psi seals, and greater-than-120-psi seals; the presence of fireclay in the surrounding strata where a mine seal is to be built; the measurement of convergence of the mine opening in which a seal has been constructed; where gob-isolation seals can be used; and the importance of periodic inspection of seals.