[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: 30CFR90.101]

[Page 654]
 
                       TITLE 30--MINERAL RESOURCES
 
  CHAPTER I--MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR
 
PART 90--MANDATORY HEALTH STANDARDS--COAL MINERS WHO HAVE EVIDENCE OF THE DEVELOPMENT OF PNEUMOCONIOSIS--Table of Contents
 
           Subpart B--Dust Standards, Rights of Part 90 Miners
 
Sec. 90.101  Respirable dust standard when quartz is present.

    When the respirable dust in the mine atmosphere of the active 
workings to which a Part 90 miner is exposed 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 a Part 90 miner is exposed at or below a concentration of 
respirable dust computed by dividing the percent of quartz into the 
number 10. The application of the formula shall not result in a 
respirable dust standard in excess of 1.0 milligrams per cubic meter of 
air. 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. 90.206 
(Approved sampling devices; equivalent concentrations).

    Example: The respirable dust associated with a Part 90 miner 
contains quartz in the amount of 20%. Therefore, the average 
concentration of respirable dust in the mine atmosphere associated with 
that Part 90 miner 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\).

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