[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: 30CFR71.101]

[Page 430]
 
                       TITLE 30--MINERAL RESOURCES
 
  CHAPTER I--MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR
 
PART 71--MANDATORY HEALTH STANDARDS--SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES--Table of Contents
 
                        Subpart B--Dust Standards
 
Sec. 71.101  Respirable dust standard when quartz is present.

    When the respirable dust in the mine atmosphere of the active 
workings contains more than 5 percent quartz, the operator shall 
continuously maintain the average concentration of respirable dust in 
the mine atmosphere during each shift to which each miner is exposed at 
or below a concentration of respirable dust computed by dividing the 
percent of quartz into the number 10. Concentrations shall be expressed 
in milligrams per cubic meter of air as measured with an approved 
sampling device and in terms of an equivalent concentration determined 
in accordance with Sec. 71.206 (Approved sampling devices; equivalent 
concentrations).

    Example: The respirable dust associated with a designated work 
position contains quartz in the amount of 20%, Therefore, the average 
concentration of respirable dust in the mine atmosphere associated with 
that designated work position shall be continuously maintained at or 
below 0.5 milligrams of respirable dust per cubic meter of air (10/
20=0.5 mg/m\3\).