30 C.F.R. § 57.8535 Seals.
Title 30 - Mineral Resources
Seals shall be provided with a means for checking the quality of air behind the seal and a means to prevent a water head from developing unless the seal is designed to impound water.
Title 30: Mineral Resources
PART 57—SAFETY AND HEALTH STANDARDS—UNDERGROUND METAL AND NONMETAL MINES
Subpart G—Ventilation
Underground Only
§ 57.8535 Seals.
