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U.S. Department of Labor

Mine Safety and Health Administration
201 12th Street South, Suite 401
Arlington, VA 22202-5450
ISSUE DATE: August 16, 2010
LAST VALIDATED: 03/31/2021


FROM:             KEVIN G. STRICKLIN  
                       Administrator for
                       Coal Mine Safety and Health

SUBJECT:     Inadequate Ventilation

This Program Information Bulletin (PIB) applies to operators of underground coal mines, miners' representatives, Mine Safety and Health Administration (MSHA) enforcement personnel, and other interested parties.

The purpose of this Program Information Bulletin (PIB) is to emphasize requirements to ensure that the working face and working places of underground coal mines are ventilated by a sufficient quantity of air so as to continuously dilute, render harmless, and carry away flammable, explosive, noxious, and harmful gases, dusts, smoke, and fumes produced during mining.

Providing sufficient air quantity in an underground mine is the principal means of ensuring that flammable, explosive, noxious, and harmful gases, dusts, smoke, and fumes are continuously diluted, rendered harmless, and carried away, as required by Section 303 of the Federal Mine Safety and Health Act of 1977. It is essential to miners' safety and health that each working face is ventilated by sufficient air quantity. Insufficient air quantity allows methane and dust to accumulate, potentially resulting in a mine fire or explosion. Dust accumulations can also cause miners to be exposed to harmful levels of respirable dust, which can cause pneumoconiosis, or "black lung disease."

In general, 30 C.F.R. § 75.325 establishes minimum quantities of air that must be provided at specified underground locations. For bituminous and lignite mines, § 75.325 requires a minimum of 3,000 cubic feet per minute (cfm) of air at each working face, as determined at or near the face end of the line curtain, ventilation tubing or other ventilation control device. The last open crosscut of each set of entries or rooms on each working section and the quantity of air reaching the intake end of a pillar line must be 9,000 cfm, at a minimum. This also includes sections of the mine that are not operating, but are capable of producing coal by simply energizing section equipment. The working face of longwalls and shortwalls must receive at least 30,000 cfm of air. Section § 75.325 also requires operators to maintain adequate ventilation during installation and removal of mechanized mining equipment.

In some cases, the specified quantities of air may be inadequate to continuously dilute, render harmless, and carry away flammable, explosive, noxious, and harmful gases, dusts, smoke, and fumes. In those cases, greater quantities of ventilating air will be required and will be specified in the operator's approved ventilation plan.

MSHA maintains an anonymous hotline to report hazardous conditions, including inadequate ventilation. The phone number is 1-800-746-1553. Persons may also report hazardous conditions to their MSHA District office. MSHA will promptly investigate any report of a hazardous condition at a mine.

On April 21, 2010, MSHA launched inspections at 57 coal mines whose enforcement history indicated a significant number of violations related to methane accumulations, ventilation, rock dusting and mine examinations. These impact inspections followed the April 5, 2010 explosion at Upper Big Branch Mine in Montcoal, West Virginia, and focused attention on mine ventilation, rock dusting, methane monitoring and mine examinations.

In addition, on May 24, 2010, the House Education and Labor Committee conducted a hearing on the Upper Big Branch explosion. The Committee heard testimony from deceased miners' families. The testimony addressed issues regarding safety conditions in existence prior to the explosion including inadequate ventilation, intentional changes to ventilation systems, high levels of methane, excessive coal float dust, "bridging out" methane monitors on mining equipment, advance notice of MSHA inspections, and retaliation for miners who raised safety and health issues.

This PIB emphasizes that MSHA intends for mine operators to fully comply with the Mine Act and MSHA's regulatory requirements.

Authority The Federal Mine Safety and Health Act of 1977, as amended, 30 U.S.C. § 801 et seq., and 30 C.F.R. § 75.325

Issuing Office and Contact Person
Mine Safety and Health Enforcement
Don Vickers, (202) 693-9760

Internet Availability
This PIB may be viewed on the Internet by accessing MSHA's home page at (, choosing "Compliance Info" and "Program Information Bulletins."