Monitoring and Sampling
Approaches to Assess Underground
Coal Mine Dust Exposures

Committee on the Study of the Control of Respirable
Coal Mine Dust Exposure in Underground Mines

Board on Earth Sciences and Resources

Board on Environmental Studies and Toxicology

Board on Health Sciences Policy

Division on Earth and Life Studies

Health and Medicine Division

A Consensus Study Report of

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This activity was supported by Contract 200-2011-38807 between the National Academy of Sciences and the National Institute for Occupational Safety and Health of the Centers for Disease Control and Prevention. Any opinions, findings, conclusions, or recommendations expressed in this publication do not necessarily reflect the views of any organization or agency that provided support for the project.

International Standard Book Number-13: 978-0-309-47601-0
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Digital Object Identifier: https:/doi.org/10.17226/25111

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Suggested citation: National Academies of Sciences, Engineering, and Medicine. 2018. Monitoring and Sampling Approaches to Assess Underground Coal Mine Dust Exposures. Washington, DC: The National Academies Press. doi: https:/doi.org/10.17226/25111.

COMMITTEE ON THE STUDY OF THE CONTROL OF RESPIRABLE COAL MINE DUST EXPOSURE IN UNDERGROUND MINES

Members

THURE E. CERLING (Chair), The University of Utah, Salt Lake City

DIRK DAHMANN, Institut für Gefahrstoff-Forschung, Bochum, Germany (Retired)

R. LARRY GRAYSON, The Pennsylvania State University, Coraopolis, PA

BRADEN T. LUSK, Missouri University for Science and Technology, Rolla, MO

MICHAEL MCCAWLEY, West Virginia University, Morgantown

RAJA V. RAMANI, The Pennsylvania State University, University Park

CECILE S. ROSE, National Jewish Health and University of Colorado Denver

EMILY A. SARVER, Virginia Polytechnic Institute and State University, Blacksburg

JOSEPH A. SBAFFONI, JAS Mine Consulting LLC, DuBois, PA

MICHAEL J. WRIGHT, United Steelworkers, Pittsburgh, PA

Staff

RAYMOND WASSEL, Project Director

ELIZABETH EIDE, Director, Board on Earth Sciences and Resources

SAMMANTHA MAGSINO, Senior Program Officer

CATHY LIVERMAN, Scholar

YASMIN ROMITTI, Research Associate

MIRSADA KARALIC-LONCAREVIC, Manager, Technical Information Center (until April 6, 2018)

RADIAH ROSE-CRAWFORD, Manager, Editorial Projects

TAMARA DAWSON, Program Coordinator

Sponsor

National Institute for Occupational Safety and Health of the Centers for Disease Control and Prevention

BOARD ON EARTH SCIENCES AND RESOURCES

Members

GENE WHITNEY (Chair), Congressional Research Service (Retired), Washington, DC

R. LYNDON (LYN) ARSCOTT, International Association of Oil & Gas Producers (Retired), Danville, California

BRENDA B. BOWEN, The University of Utah

CHRISTOPHER (SCOTT) CAMERON, GeoLogical Consulting, LLC

RODNEY C. EWING, NAE, Freeman Spogli Institute for International Studies and Stanford University, Stanford, California

CAROL P. HARDEN, The University of Tennessee

THORNE LAY, NAS, University of California, Santa Cruz

ANN S. MAEST, Buka Environmental, Boulder, Colorado

ZELMA MAINE-JACKSON, Washington State Department of Ecology, Nuclear Waste Program, Richland, Washington

MARTIN W. MCCANN, Jack R. Benjamin and Associates and Stanford University, Menlo Park, California

JAMES M. ROBERTSON, Wisconsin Geological and Natural History Survey, Madison

JEFFREY N. RUBIN, Tualatin Valley Fire and Rescue

JAMES SLUTZ, National Petroleum Council, Washington, DC

SHAOWEN WANG, University of Illinois at Urbana-Champaign

ELIZABETH J. WILSON, Dartmouth College

BESR Staff

ELIZABETH A. EIDE, Director

ANNE M. LINN, Scholar

DEBORAH GLICKSON, Senior Program Officer

SAMMANTHA L. MAGSINO, Senior Program Officer

COURTNEY R. DEVANE, Administrative Coordinator

NICHOLAS D. ROGERS, Financial and Research Associate

YASMIN ROMITTI, Research Associate

CARLY BRODY, Senior Program Assistant

RAYMOND M. CHAPPETTA, Senior Program Assistant

ERIC J. EDKIN, Senior Program Assistant

BOARD ON ENVIRONMENTAL STUDIES AND TOXICOLOGY

Members

WILLIAM H. FARLAND (Chair), Colorado State University, Fort Collins

LESA AYLWARD, Summit Toxicology, LLP, Falls Church, VA

RICHARD A. BECKER, American Chemistry Council, Washington, DC

E. WILLIAM COLGLAZIER, American Association for the Advancement of Science, Washington, DC

DOMINIC M. DITORO, University of Delaware, Newark

DAVID C. DORMAN, North Carolina State University, Raleigh

ANNE FAIRBROTHER, Exponent, Inc., Philomath, OR

GEORGE GRAY, The George Washington University, Washington, DC

STEVEN P. HAMBURG, Environmental Defense Fund, New York, NY

ROBERT A. HIATT, University of California, San Francisco

R. JEFFREY LEWIS, ExxonMobil Biomedical Sciences, Inc., Annandale, NJ

H. SCOTT MATTHEWS, Carnegie Mellon University, Pittsburgh, PA

ROBERT PERCIASEPE, Center for Climate and Energy Solutions, Arlington, VA

R. CRAIG POSTLEWAITE, Department of Defense, Burke, VA

REZA J. RASOULPOUR, Dow AgroSciences, Indianapolis, IN

MARK A. RATNER, Northwestern University, Evanston, IL

JOAN B. ROSE, Michigan State University, East Lansing

GINA M. SOLOMON, Public Health Institute, Oakland, CA

ROBERT M. SUSSMAN, Sussman and Associates, Washington, DC

DEBORAH L. SWACKHAMER, University of Minnesota, St. Paul

PETER S. THORNE, The University of Iowa, Iowa City

BEST Senior Staff

TERESA A. FRYBERGER, Director (until April 30, 2018)

ELLEN K. MANTUS, Scholar and Director of Risk Assessment

RAYMOND A. WASSEL, Scholar and Director of Environmental Studies

SUSAN N. J. MARTEL, Senior Program Officer for Toxicology

BOARD ON HEALTH SCIENCES POLICY

Members

JEFFREY KAHN (Chair), NAM, Johns Hopkins University, Baltimore, MD

DAVID BLAZES, Bill & Melinda Gates Foundation, Seattle, WA

ROBERT M. CALIFF, NAM, Duke University, Durham, NC

R. ALTA CHARO, NAM, University of Wisconsin–Madison

LINDA HAWES CLEVER, NAM, California Pacific Medical Center, Portola Valley

BARRY S. COLLER, NAS/NAM, The Rockefeller University, New York, NY

BERNARD A. HARRIS, JR., Vesalius Ventures, Houston, TX

MARTHA N. HILL, NAM, Johns Hopkins University School of Nursing, Baltimore, MD

ALAN M. JETTE, NAM, Boston University School of Public Health, Boston, MA

PATRICIA A. KING, NAM, Georgetown University Law Center, Washington, DC

STORY C. LANDIS, NAM, National Institute of Neurological Disorders and Stroke, Freeport, ME

HARRY T. ORR, NAM, University of Minnesota, Minneapolis

BRAY PATRICK-LAKE, Duke University, Erie, CO

DIETRAM A. SCHEUFELE, University of Wisconsin–Madison

UMAIR A. SHAH, Harris County Public Health and Environmental Services, Houston, TX

ROBYN STONE, NAM, LeadingAge, Washington, DC

HSP Staff

ANDREW M. POPE, Senior Board Director

STEPHANIE YOUNG, Program Coordinator

Acknowledgments

This Consensus Study Report was reviewed in draft form by individuals chosen for their diverse perspectives and technical expertise. The purpose of this independent review is to provide candid and critical comments that will assist the National Academies of Sciences, Engineering, and Medicine in making each published report as sound as possible and to ensure that it meets the institutional standards for quality, objectivity, evidence, and responsiveness to the study charge. The review comments and draft manuscript remain confidential to protect the integrity of the deliberative process.

We thank the following individuals for their review of this report:

Although the reviewers listed above have provided many constructive comments and suggestions, they were not asked to endorse the conclusions or recommendations nor did they see the final draft of the report before its release. The review of this report was overseen by the review coordinator, Paul A. Locke, Johns Hopkins Bloomberg School of Public Health, and the review monitor, Kirk R. Smith, University of California, Berkeley. They were responsible for making certain that an independent examination of this report was carried out in accordance with the standards of the National Academies and that all review comments were carefully considered. Responsibility for the final content rests entirely with the authoring committee and the National Academies.

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Preface

Dust generated during underground coal mining operations includes particles small enough to be deposited in the airways and the gas-exchange region of a miner’s lung, when inhaled. Chronic exposure to those particles, referred to as respirable coal mine dust (RCMD), puts miners at risk for various lung diseases, including coal workers’ pneumoconiosis, emphysema, silicosis, and chronic bronchitis. This report is about methods for monitoring and sampling miners’ exposure to RCMD. Results from the implementation of those methods are used for determining whether miners’ exposures are within regulatory limits and informing mine operators’ efforts to reduce those exposures.

The Mine Safety and Health Administration (MSHA) is the federal agency responsible for setting and enforcing mine safety and health standards. On May 1, 2014, MSHA’s final rule, entitled Lowering Miners’ Exposure to Respirable Coal Mine Dust, Including Continuous Personal Dust Monitors, was issued as part of an ongoing effort to protect miners from the health risks of lung diseases associated with RCMD inhalation. (Chapter 1 of this report provides an overview of the rule’s main requirements.)

Some coal mine operators and mining associations had expressed various concerns about the efficacy of the monitoring and sampling protocols in MSHA’s new rule in aiding decisions regarding the control of RCMD and mine worker exposure. For example, MSHA’s dust rule requires the use of a continuous personal dust monitor (CPDM) for measurement of RCMD mass concentrations in near real time and determining compliance with the regulatory exposure limit. Concerns were expressed as to whether CPDM measurements will accurately reflect the concentration of particles in coal mine dust that are of relevance to coal mining–related respiratory diseases. CPDM measurements of RCMD also include limestone particles or other types of rock dust that are typically applied in mines to meet requirements for controlling the combustibility of coal dust.

In the Fiscal 2016 Consolidated Appropriations, Congress directed the National Institute for Occupational Safety and Health (NIOSH) to arrange for a study with the National Academy of Sciences to consider monitoring technologies and sampling protocols used in the United States and in similarly industrialized countries for the control of RCMD exposure in underground coal mines; effects of rock dust mixtures and their application on RCMD measurements; and the efficacy of current monitoring technologies and sampling approaches. The request also called for science-based conclusions regarding optimal monitoring and sampling strategies to aid mine operators’ decision making related to reducing respirable coal mine dust exposure to miners in underground coal mines.

In response to the congressional request, the National Academies of Sciences, Engineering, and Medicine assembled a committee of 10 members who had expertise in underground mine air quality, exposure science, mine worker health and safety regulations, industrial hygiene, occupational medicine and environmental health, mining engineering, and international perspectives. (The committee’s formal statement of task is presented in Appendix A and biographical sketches of the members are presented in Appendix B.)

In responding to the request from Congress, the committee was asked to identify important research gaps regarding monitoring and sampling protocols for controlling miners’ RCMD exposures. It was asked not to recommend changes to the requirements of MSHA’s final rule for lowering miners’ exposure to respirable coal mine dust, as the development of those requirements involves considerations beyond the scientific and technical focus of this study.

In the course of preparing its report, the committee held public information-gathering sessions during four of its meetings to hear presentations from members of Congress’ professional

staff; representatives of MSHA, NIOSH, National Mining Association, several coal mining companies, United Mine Workers of America, a rock dust manufacturer; and relevant experts from Australia and the Republic of South Africa. Two of the committee’s information-gathering sessions were held in Charleston and Morgantown, West Virginia, to receive input from individual coal miners and others living in areas where underground coal mining occurs. The committee gratefully acknowledges the individuals listed in Appendix C for their presentations to the committee during the public sessions.

Members of the committee visited the Dana Mine in Mount Morris, Pennsylvania, and the Arch/Coal Leer Mine in Grafton, West Virginia. The committee is very appreciative of the personnel at those mines for allowing members to observe coal mine operations, in situ use of CPDMs, and exposure reduction practices. The committee also appreciates receiving extensive written materials from MSHA, NIOSH, coal mine companies, and other organizations.

The committee is grateful for the assistance of the project staff members for the support they provided.

Thure E. Cerling, Chair
Committee on the Study of the Control of Respirable Coal Mine Dust Exposure in Underground Mines

Abbreviations

Contents

SUMMARY

1 INTRODUCTION

Committee’s Statement of Task

Respirable Coal Mine Dust: Constituents and Sources

Overview of Underground Coal Mining Methods and Job Duties

Toxicity and Diseases Associated with Coal Mine Dust Exposure

Recent Trends in Coal Mine Dust Lung Diseases and in Mining

Early Regulatory Efforts and Past Recommendations

Dust Control Measures

The 2014 Dust Rule

Conclusion

Organization of the Report

References

2 EFFECTS OF ROCK DUST APPLICATIONS ON COAL MINE DUST MEASUREMENTS

Rock Dust Technology and Practices

Particle Size Distributions of Rock Dust

Silica Content of Rock Dust

Potential Health Effects of Rock Dust Exposure

Conclusions

References

3 EXPOSURE MONITORING AND SAMPLING APPROACHES USED IN DIFFERENT INDUSTRIALIZED COUNTRIES

Monitoring and Sampling Approaches Required in Selected Countries

A Comparison of Requirements

Conclusions

References

4 EFFICACY OF CURRENT MONITORING TECHNOLOGIES AND SAMPLING APPROACHES

Determine Compliance with RCMD Standards for Designated Occupations on Sampled Shifts

Inform Workers in Designated Occupations of a Need to Change Behavior in Response to Dust Concentration Readings While Conducting Tasks

Provide Information to Mine Operators for Addressing Dust Issues Through Process Control

Determine Sample Variability for Designated Areas and Designated Occupations

Provide Information on Crystalline Silica Exposure for Designated Occupations

Conclusions

References

5 OPTIMIZING MONITORING AND SAMPLING STRATEGIES

An Ideal Monitoring and Sampling Program

Optimal Monitoring and Sampling Strategies

Technology Development Needs

Conclusions

References

6 OVERALL CONCLUSIONS AND RECOMMENDATIONS

Trends in Disease Epidemiology and Mining Practices

Efficacy of Current Monitoring and Sampling in Underground Mines in the United States

Optimal Monitoring and Sampling Strategies to Aid Mine Operators’ Decision Making

Effects of Rock Dusting on RCMD Measurements

Sampling and Monitoring Practices Used in Different Industrialized Countries

Recommendations

APPENDIXES

A STATEMENT OF TASK

B COMMITTEE MEMBER BIOSKETCHES

C OPEN-SESSION MEETING AGENDAS

D GLOSSARY

E COAL MINING IN THE UNITED STATES

F UNDERGROUND COAL MINING METHODS AND ENGINEERING DUST CONTROLS

G MANDATORY AIRBORNE DUST STANDARDS FOR U.S. UNDERGROUND COAL MINES

BOXES, FIGURES, AND TABLES

BOXES

3-1 Indian Sampling Requirements

4-1 NIOSH Description of the Continuous Personal Dust Monitor

5-1 Potential Uses of Monitoring Data to Aid in Mine Operators’ Decision Making

F-1 Examples of Dust Control Plan Items for Longwall Mining Units in Underground Mines

F-2 Examples of Dust Control Plan Items for Continuous Miner Units in Underground Mines

FIGURES

S-1 Percentage of examined U.S. underground miners with coal workers’ pneumoconiosis (CWP), for 1970 to 2012

1-1 Chest radiographs of normal lung, simple CWP, and progressive massive fibrosis

1-2 Percentage of examined U.S. underground miners with coal workers’ pneumoconiosis (CWP), for 1970 to 2012

1-3 Map of CWP “hot spots” by county, showing a particularly high proportion of evaluated miners with CWP in central Appalachian areas of West Virginia, Virginia, and Kentucky

1-4 Prevalence of coal workers’ pneumoconiosis by state: Enhanced Coal Workers’ Health Surveillance Program, 2005–2009

1-5 (A) Photograph of a left lung removed from a coal miner with rapidly progressive pneumoconiosis. The upper lobe is completely replaced by progressive massive fibrosis (PMF)

2-1 Time series of coal mine explosion fatalities in the United States (USA), Republic of South Africa (SA), and Australia (Aus)

2-2 Incombustible content required with varying coal dust size distributions using Bulletin 369 specification rock dust

2-3 Inerting pulverized Pittsburgh coal with limestone rock dust including sieved size fractions and 250-840 μm (60-20 mesh) particles in the 1 m³ chamber

2-4 Left: In this sample, 78 percent passes 200 mesh, 66 percent passes 325 mesh, and 43.5 percent passes 10 µm. Right: In this sample, 98 percent passes 200 mesh, 91 percent passes 325 mesh, and 55 percent passes 10 µm

4-1 Comparison of penetration and deposition criteria for the gas-exchange region of the lung by particle mass

4-2 Aerodynamic particle size distributions from mass measurements for selected underground coal mines showing the predominance of particle sizes 10 µm and greater

4-3 The amount by which the RCMD criterion differs from the mass of material predicted to be deposited in the gas exchange region (DEa) of the lungs (ICRP, 1994), where coal workers’ pneumoconiosis occurs, is a function of the aerodynamic equivalent mass size distribution of the dust

4-4 Conceptual model of how information from the CPDM might be used to develop institutional change

4-5 Process chart for effecting a behavioral change

4-6 Magnitude of the effect of behavioral changes by type of reinforcement

4-7 Internal view of components of CPDM earlier model with caplamp and caplamp battery

4-8 CPDM (PDM3700) with sampling inlet line designed to be clipped to the miner’s lapel or other clothing within the miner’s personal breathing zone

4-9 Continuous personal dust monitor (PDM3700) with cover panel removed

4-10 Expected measurement imprecision (estimated coefficient of variation in dust concentration measurements) as a function of time-weighted average dust concentration sampled for 480 minutes

4-11 Comparison of measurement data form a coal mine dust personal sampler unit (CMDPSU) and a precommercial personal dust monitor (PDM, later referred to as the CPDM) with bias corrections

5-1 Process for developing and implementing an ideal RCMD monitoring and sampling program

E-1 Coal production trends of the five lead producers, 1980-2012

E-2 Coal production million tons, east/west demarcation by Mississippi River

E-3 U.S. coal production distribution by rank of coal

E-4 A generalized schematic of methods of mining a coal seam

E-5 Distribution of U.S. coal production by mining method

E-6 Number of coal mines in the U.S.: total and by mining method, 2010-2016

E-7 Number of miners employed in coal mines: total and by mining method, 2010-2017

E-8 Distribution of U.S. underground coal mines by mine size, 2010-2016

E-9 Distribution of underground coal mines in the states of Kentucky, Virginia, West Virginia, and Pennsylvania by mine size, 2010-2016

F-1 Schematic of a room-and-pillar coal mine section

F-2 Details of the longwall face

F-3 Layout of sprays on a continuous miner with blocking sprays

F-4 Layout of longwall panels. Transport of miners, supplies, coal, and intake air occurs through the headgate entries

F-5 Longwall ventilation plan

F-6 Shearer clearer water spray arrangement

F-7 Shields equipped with water sprays

F-8 Average dust concentrations for U.S. longwall and continuous mining operations

TABLES

1-1 Reported RCMD Concentrations in Underground Coal Mines by Mining Method, April 2016 to March 2017

2-1 U.S. Rock Dusting Regulations

3-1 Coal Mining and Underground Miner Exposure Monitoring in Selected Countries

4-1 Objectives and Assumptions for Required Monitoring and Sampling Methods

4-2 Selected Purposes of Air Sampling

5-1 Monitoring Techniques and Expected Capabilities for RCMD Exposures

5-2 Potential Outcomes from Required Monitoring and Sampling Methods, Assumptions, and Components of Optimal Monitoring and Sampling Strategies

F-1 MSHA RCMD Samples, 2009-2012

F-2 Longwall MSHA RCMD Samples, 2009-2012

G-1 Underground Dust Exposure Concentrations in 1969 and 1991

G-2 Designated Occupation Sampling of RCMD Mass Concentrations in Underground Coal Mines by Mining Method for Regulatory Compliance, April 2016 to March 2017

G-3 Other Designated Occupation Exposures to RCMD in Underground Coal Mines by Mining Method, April 2016 to March 2017

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