Final Rule on Sealing of Abandoned Areas

MSHA Mine Seal Requirements

The final regulation on sealing abandoned areas addresses seal strength, design, construction, maintenance, repair, and monitoring of atmospheres behind seals to reduce explosion risks in underground coal mines.

Seals must be designed to withstand 50 psi when the atmosphere behind the seal is inert, and at least 120 psi when the atmosphere is not inert.
Sealed areas must be monitored for methane and oxygen concentrations, as well as leakage direction. Seals rated 120 psi or greater require sampling until design strength is reached; seals below 120 psi must be maintained inert.

Seal Design Application Guidelines (30 CFR § 75.335(b))

Section 75.335(b) requires seal design applications to follow specific criteria. The following guidance assists engineers submitting seal designs to MSHA for approval.

Guidelines for the Seal Design Application

Compliance Guide: Questions and Answers

This document provides guidance in a question-and-answer format from the perspective of mine operators regarding the final rule.

Sealing Abandoned Areas Final Rule FAQs

20 PSI Seal Information

Stakeholder Meeting Presentation (April 18, 2008)

PDF Version

Approved Seals Under the Final Rule

Seals Designed to Withstand 50 psi

Seals Designed to Withstand 120 psi

Seals Designed to Withstand Greater Than 120 psi

No seals are currently approved in this category.

Mine Inerting Information

The following resource lists sources for inerting gases and generators known to MSHA.

Inerting Gas Sources and Generators