[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: 30CFR27.23]

[Page 144]
 
                       TITLE 30--MINERAL RESOURCES
 
  CHAPTER I--MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR
 
PART 27--METHANE-MONITORING SYSTEMS--Table of Contents
 
             Subpart B--Construction and Design Requirements
 
Sec. 27.23  Automatic warning device.

    (a) An automatic warning device shall be suitably constructed for 
incorporation in or with permissible and approved equipment that is 
operated in gassy mines and tunnels.
    (b) An automatic warning device shall include an alarm signal 
(audible or colored light), which shall be made to function 
automatically at a methane content of the mine atmosphere between 1.0 to 
1.5 volume percent and at all higher concentrations of methane.
    (c) It is recommended that the automatic warning device be 
supplemented by a meter calibrated in volume percent of methane.

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