[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: 30CFR23.1]

[Page 136]
 
                       TITLE 30--MINERAL RESOURCES
 
  CHAPTER I--MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR
 
PART 23--TELEPHONES AND SIGNALING DEVICES--Table of Contents
 
Sec. 23.1  Purpose.

    (a) The purpose of investigations under this part is to promote the 
development of telephones and signaling devices that may be used safely 
in mines, especially in coal mines that may have gassy or dust-laden 
atmospheres. This schedule supersedes Schedule 9A, issued under date of 
December 5, 1922, and becomes effective October 18, 1938.
    (b) Telephones and signaling devices approved under the requirements 
of this part will be termed ``permissible'' by MSHA, and if actively 
marketed will be listed as such in publications relating to permissible 
equipment, for the information of State mine inspection departments, 
compensation bureaus, mine operators, miners, and others interested in 
safety equipment for mines.