[Code of Federal Regulations]
[Title 30, Volume 1]
[Revised as of July 1, 2002]
From the U.S. Government Printing Office via GPO Access
[CITE: 30CFR75.327]

[Page 476-477]
 
                       TITLE 30--MINERAL RESOURCES
 
  CHAPTER I--MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR
 
PART 75--MANDATORY SAFETY STANDARDS--UNDERGROUND COAL MINES--Table of Contents
 
                         Subpart D--Ventilation
 
Sec. 75.327  Air courses and trolley haulage systems.

    (a) In any mine opened on or after March 30, 1970, or in any new 
working section of a mine opened before that date, where trolley haulage 
systems are maintained and where trolley wires or trolley feeder wires 
are installed, an authorized representative of the Secretary shall 
require enough entries or rooms as intake air courses to limit the 
velocity of air currents in the haulageways to minimize the hazards of 
fires and dust explosions in the haulageways.
    (b) Unless the district manager approves a higher velocity, the 
velocity of the air current in the trolley haulage entries shall be 
limited to not more than 250 feet per minute. A higher air

[[Page 477]]

velocity may be required to limit the methane content in these haulage 
entries or elsewhere in the mine to less than 1.0 percent and provide an 
adequate supply of oxygen.