[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: 30CFR23.6]

[Page 137]
 
                       TITLE 30--MINERAL RESOURCES
 
  CHAPTER I--MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR
 
PART 23--TELEPHONES AND SIGNALING DEVICES--Table of Contents
 
Sec. 23.6  General requirements for approval.

    Telephones and signaling devices shall be durable in construction, 
practical in operation, and suitable for conditions of underground 
service. They shall offer no probable explosion hazard under normal 
operation if use in gassy or dusty mine atmospheres.