ISSUE DATE: 06/18/2010 

PROGRAM INFORMATION BULLETIN NO. P10-06 

FROM: KEVIN G. STRICKLIN

 Administrator for 

 Coal Mine Safety and Health 

SUBJECT: Low-Weight Gain Respirable Dust Samples Submitted by Mine 

 Operators 

Scope

This Program Information Bulletin (PIB) applies to Mine Safety and Health 

Administration (MSHA) Coal Mine Safety and Health personnel, coal mine operators, 

and independent contractors. 

Purpose

This bulletin notifies mine operators of new MSHA procedures for possible voiding of 

operator respirable dust samples taken to fulfill the sampling requirements of 30 C.F.R. 

Part 70. Samples having unreasonably low dust concentrations may be voided for not 

being representative of respirable dust levels under typical mining conditions. 

Information 

Requirements in 30 C.F.R. Part 70 require valid respirable dust samples to be collected 

by an operator and transmitted to MSHA each bimonthly period or in response to a 

notice or citation. A valid respirable dust sample is defined in 30 C.F.R. § 70.2 as a 

sample collected and submitted as required by 30 C.F.R. Part 70 and not voided by 

MSHA. 

Effective July 1, 2010, MSHA will evaluate the validity of each operator respirable dust 

sample collected on a designated occupation (DO), non-designated occupation (NDO), 

or designated area (DA) on a mechanized mining unit (MMU) determined to have a 

concentration of 0.100 mg/m3 or less by comparing it to the most recent MSHA intake 

air sample result from the same MMU. Any MMU sample that (1) has a 0.100 mg/m3

concentration and (2) is determined to have a concentration that is less than the MSHA 

intake air sample may be voided as being an unrepresentative sample using the void 

code URS (Unrepresentative Sample). 
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When MSHA identifies a sample meeting these criteria, the Agency will notify the mine 

operator by a voided sample notification. Upon notification, the mine operator either

(1) may submit, in writing, information sufficient to substantiate that the sample is 

representative of the normal mining activity associated with the sample or (2) may 

replace the sample during the bimonthly sampling period. If reliable substantiating 

information is timely provided, MSHA will consider the subject submission valid. 

Alternatively, MSHA will accept a valid and timely submitted replacement sample. 

To maintain the integrity of the sampling program, certified persons signing the dust 

data card have the responsibility for ensuring that respirable dust samples submitted to 

MSHA are representative of the mining environment. To be representative of the 

mining environment, the samples must accurately reflect the concentration of respirable 

dust in the active workings. 

Background

MSHA has evaluated the results of respirable dust samples collected by mine operators 

and MSHA inspectors on MMUs. A percentage of the operators’ designated occupation 

samples, approximately seven to nine percent, show concentrations of less than 0.100 

mg/m3. MSHA experience shows that intake air regularly falls in the 0.100 mg/m3 to 

0.300 mg/m3 range and this air should be significantly less dust-laden than air in 

MMUs where coal is being mined. Many of these low-weight samples were found to 

contain less dust than section intake air samples collected by MSHA inspection 

personnel. Therefore, MSHA believes that low-weight dust samples resulting in 

concentrations of 0.100 mg/m3 or less submitted for occupations exposed to multiple 

dust-generation sources on MMU merit scrutiny to determine whether they are 

representative of respirable dust levels under typical mining conditions. 

MSHA has chosen not to issue this PIB pursuant to notice-and-comment rulemaking 

because it believes that it is a general statement of policy under 5 U.S.C. 553(b)(3)(A). 

Authority 

The Federal Mine Safety and Health Act of 1977, as amended, 30 U.S.C. § 804 et seq., 30 

C.F.R. Parts 70, 71 and 90 

Issuing Offices and Contact Persons

Coal Mine Safety and Health, Health Division 

Robert A. Thaxton, (202) 693-9515 

Email: thaxton.robert@dol.gov

 

Internet Availability

This information bulletin may be viewed on the Internet by accessing MSHA’s home 

page http://www.msha.gov. 
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Distribution 

Coal and All-Volume Program Policy Manual Holders 

Coal Mine Operators 

Coal Independent Contractors 

Coal Special Interest Groups