[Code of Federal Regulations]

[Title 30, Volume 1]

[Revised as of July 1, 2006]

From the U.S. Government Printing Office via GPO Access

[CITE: 30CFR71.101]



[Page 439]

 

                       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\).