Application of Prevention through Design for Hearing Loss

in the Mining Industry

Peter G. Kovalchik , Rudy J. Matetic, Adam K. Smith, Susan B. Bealko

National Institute for Occupational Safety and Health

Abstract

Introduction: Overexposure to noise remains a widespread and serious health hazard in the U.S. service providing and goods producing industries.

Excessive noise can lead to poor verbal communication and reduce the ability to recognize warning signals. These dangerous work conditions can

also cause stress and fatigue. Occupational hearing loss is a permanent illness, with no recovery currently possible. Method: National Institute for

Occupational Safety and Health (NIOSH) has recognized Noise Induced Hearing Loss (NIHL) as one of the ten leading work related diseases and

injuries in the United States, and has emphasized its importance as one of the critical areas expressed in the National Occupational Research

Agenda. Results: One of the most serious noise problems in the goods producing industries is the operation of continuous mining machines during

underground coal mining. In order to minimize occupational hearing loss, noise hazards are “designed out” early in the design process. NIOSH is

leading a national initiative called Prevention through Design (PTD) to promote this concept. This paper describes the quiet by design approach of

a noise control that reduced noise exposures of continuous mining machine operators by 3dB(A) using the four functional areas of PTD, namely

Practice, Policy, Research, and Education.

Keywords: Noise Exposure; Hearing Loss; Occupational; PTD; Noise Control; Noise; Mining; Mine Heatlh

1. Problem

Prior to 2004, the Bureau of Labor Statistics (BLS) classified

hearing lossin the “all other illnesses” category. In 2004, hearing

loss was categorized as a separate illness that accounted for 11%

of work related illnesses. In 2005, hearing loss cases stayed

relatively unchanged at 11% from the previous year (U.S.

Department of Labor, 2006a). Occupational data for coal, metal,

and nonmetal mining were provided by the Department of

Labor, Mine Safety and Health Administration (MSHA). MSHA

has not adopted the revised OSHA recordkeeping requirements

for 2005, therefore data for coal, metal, and nonmetal mining

are not comparable with the data for other industries. The MSHA

coal data from 2000 to 2005 showed operators that exceeded

100% noise dosage were from seven different types of machines:

auger miners, bulldozers, continuous mining machines, front

end loaders, roof bolters, shuttle cars (electric), and trucks (U.S.

Department of Labor, Mine Safety and Health Administration,

2000–2005). Also, continuous mining machines were the

number one machine among all the equipment whose operators

exceed 100% dosage. There are approximately 600 mines with

over 4,000 continuous mining machine operators (U.S. Department of Labor, Mine Safety and Health Administration, 2005;

U.S. Department of Labor Bureau of Labor Statistics, 2006b).

Fig. 1 shows the percentage of continuous mining machine

operators that exceed 100% noise dose from 2000 to 2005

according to the MSHA database (U.S. Department of Labor,

Mine Safety and Health Administration, 2000–2005).

Continuous mining machines are large underground machines

that cut and gather coal at the working faces. The coal is

transported via an onboard conveyor to the back of the machine

where it is loaded onto either another conveyor or a piece of

mining equipment designed to carry the coal away from the

working face. One of the major noise sources on a continuous

mining machine is this onboard conveyor, which consists of

a chain with flight bars that drag the coal along the base of the

conveyor system (Kovalchik, Johnson, Burdisso, Duda, & Durr,
Fig. 1. CMM Operators that Exceed 100% Dose.

2002). The metal chain and flight bars in contact with the metal

base and the coal itself are a significant noise source and

contribute considerably to the noise exposure of workers at the

face. Continuous miner operators stand near the chain conveyor,

towards the back of the machine, and receive a significant portion

of their noise dosage while the conveyor is running.

The quiet-by-design approach will be emphasized by utilizing

noise treatments to reduce excessive exposure to noise on the job

and prevent additional cases of NIHL in the mining population.

This paper describes the quiet-by-design or Prevention through

Design (PtD) approach. This is the latest effort by NIOSH's

Pittsburgh Research Laboratory (PRL) Hearing Loss Prevention

Branch (HLPB) to reduce noise exposure of continuous mining

machine operators in coal mining environments. Specifically,

this paper concentrates on how PtD was used to create a noise

control for a conveyor of a Joy Mining Machinery continuous

mining machine.

2. Method

The PtD method was used to develop a noise control to reduce

the noise exposure of continuous mining machine operators in

coal mining environments. Through utilizing the four functional

areas (research, policy, practice, and education) of the PtD

process, the PtD approach consisted of developing collaborations

or partnerships, procedures, resources, implementation plans,

design strategies, case studies, and research to practice (r2p)

initiatives from identification of the problem to implementation.

Collaborations were established with Joy Mining Machinery,

Consol Energy, C.U.E. Inc., MSHA, United Mine Workers of

America (UMWA), and NIOSH to reduce the occurrence of NIHL

among continuous mining machine operators. The collaborators

were also representatives of the Coal Noise Partnership, which

consists of representatives from the UMWA, Bituminous Coal

Operators Association (BCOA), MSHA, and the National Mining

Association (NMA). Additionally, mining equipment manufacturers and suppliers participated within the partnership. The

purpose of the partnership is to collectively work as a team to

reduce the worker exposure to noise and the prevention of NIHL

among miners.

Research conducted to reduce continuous mining machine

conveyor noise was divided up with NIOSH acting as the

technical arm of the partnership. NIOSH developed the test

plans, design strategies, and conducted the evaluations. Joy

Mining Machinery provided resources such as the continuous

mining machine and continuous mining machine parts. C.U.E.

Inc. also provided resources that consisted of materials for the

noise control. Consol Energy Inc. provided a mine site as a

resource for field evaluation, and both MSHA and the UMWA

supported the testing by providing input and participated in the

in-mine testing.

In general, the design and implementation strategy consisted of

five areas: (a) gathering and analyzing information on noise

emission levels from the continuous mining machine conveyor;

(b) design, development, implementation, and testing of engineering controlsforthe conveyor;(c) motivating the use of engineering

noise control through collaboration with other government

agencies, unions, equipment manufacturers, and standard setting

bodies; (d) implementing the noise control and evaluating the

effectiveness and feasibility; and (e) conducting a case study to

determine the amount of reduction in operator noise exposure.

3. Results

NIOSH researchers addressed thisissue by developing a chain

conveyor with coated flights as a noise control to reduce the sound

power emitted of continuous mining machines. By coating the

flight bars with a heavy duty, highly-durable urethane, the metal

to metal and metal to coal contact was reduced with a resulting

reduction in noise levels. NIOSH designed, developed, lab tested,

and field tested the noise control in partnership with labor (United

Mine Workers of America), industry (National Mining Association, Bituminous Coal Operators Association), manufacturers

(Joy Manufacturing), suppliers (C.U.E Inc), and MSHA

stakeholders. The field tests demonstrated the coated flight bars

as an effective noise control, obtaining a 3 dB(A) noise exposure

reduction. In addition, the coated flights verified to be durable in a

harsh underground environment.

A cost analysis was also conducted to determine if the coated

flight bars were economically feasible. The results estimated the

coated flight bars would increase the cost of the standard

conveyor chain life by 20%. However, the coated flight bars

extended conveyor chain life by a factor of three compared to

chains with standard flight bars.

NIOSH accomplished policy initiatives with the use of a

Cooperative Research and Development Agreement (CRADA),

which provided an opportunity for NIOSH/CDC researchers to

collaborate with colleagues from industry in the pursuit of

common research. NIOSH was able to promote Joy Mining

Machinery and C.U.E. Inc. in collaborating on reducing conveyor

noise of the continuous mining machine. This was accomplished

by showing Joy Mining Machinery and C.U.E. Inc. the benefitsin

implementing the control, which included: improved access to

government researchers and facilities, better access to expertise

related to research results and inventions, exclusive (or nonexclusive) licenses on inventions made under a CRADA, and

potential profit from new products and processes developed.

Underground field evaluations were used to demonstrate to

MSHA that the noise control developed for quieting the conveyor

of continuous mining machines was a feasible engineering control

according to the MSHA 30 Code of Federal Regulations (CFR)
Table 1

MSHA Dosimter Parameters

Parameters Setting Designation

Weighting

Treshold Level

A

90 dB

MSHA Permissible Exposure Level (PEL)

Exchange Rate

Criterion Level

5 dB

90 dB

Response

Upper Limit

Slow

140 dB

section 62.130 (U.S. Department of Labor, Mine Safety and

Health Administration, 2008). In order to be a feasible

engineering noise control, the treatment should reduce noise

exposure and be economically and technologically achievable.

Technologically achievable requires that the noise control show

any of the following requirements (U.S. Department of Labor,

Mine Safety and Health Administration, 1999): (a) a 3 dB(A) or

more reduction in exposure as a single noise control or in

combination with other treatments, and/or (b) achieves compliance according to MSHA regulations.

In general the evaluation consisted of portal to portal dosimetry

data utilizing a time motion study. Dosimetry determines the

amount of acoustic noise that a worker is exposed to during a

work shift. The time motion study relates the task with the noise

exposure time of the operator. Two days of dosimetry data are

needed. On one day, dosimetry data would be collected on the

standard chain and on the other day dosimetry data would be

collected on the treated chain. All measurements were performed

with dosimeters set to MSHA parameters shown in Table 1.

The same continuous mining machine and operator was used

for all underground measurements. Results demonstrated the

amount of acoustic noise the continuous mining operator was

exposed to with the standard chain and the treated chain during

each work shift. The results were published and presented to

MSHA. The information provided impact evidence to MSHA for

citing the control as a noise control in the Program Information

Bulletin (PIB) P04-18, “Technologically Achievable, Administratively Achievable, and Promising Noise Controls (30 CFR

Part 62).” The PIB provides information and guidance relative to

promising and technologically and administratively achievable

noise controls.

4. Discussion

Through educating the Coal Noise Partnership, NIOSH

addressed representatives of the workers, the mining companies,

the mining machine manufacturers, and the regulatory/enforcement arm of the government for coal mining. The acceptance of

the technology as an effective noise control by members of the

Coal Noise Partnership was the starting point in getting a

manufacturer to produce and sell the coated flight bar chain

conveyor, along with getting several mines to use the noise

control. NIOSH provided evidence on the effectiveness and

feasibility of the noise control to the Coal Noise Partnership. As

a result, MSHA cited the coated flight bar concept as part of the

“Technologically Achievable, Administratively Achievable, and

Promising Noise Controls (30 CFR Part 62)” on the MSHA

Program Information Bulletin P04-18.

NIOSH also obtained testimonies from several mine operators

at two coal mine sites that were using the noise control as an

educational tool. The operators stated they observed a clear

reduction in the noise level of the continuous mining machine. In

addition, the mine workers have reported that the control was easy

to implement and has a high level of durability.

NIOSH has transferred the findings of this research effort to

interested industry parties. This was accomplished through

journal articles, conference proceedings, conference presentations, industry/labor workshops, and industry/labor/NIOSH

partnership meetings. Technology transfer efforts, such as

workshops, conference presentations, and journal articles are

selected based upon their ability to reach the target audience for

the research. These findings were used to show the merit of the

coated flight bars to manufacturers. The coated flight bar chain

conveyor is currently being manufactured and sold by Joy

Manufacturing, Inc. (package number: 100201770), who produces over 80% of the continuous mining machines in the United

States. In addition, Joy Mining Machinery has provided an initial

investment of one-million dollars to a new chain facility in

pursing a “quiet-by-design” approach for continuous mining

machine chains.

5. Impact on industry

Within the mining industry, MSHA provides information

relative to promising and feasible noise engineering controls

through a PIB. The PIB provides guidance to the industry on

technology and administratively achievable engineering and

administrative noise controls. At this time, there is limited

information for industry representatives on the process of

implementing noise engineering controls at their respective

companies. Introduction and implementation of engineering

controls in the workplace is an organizational issue that intersects across management, safety, training, and maintenance

departments in an organization. The impact of successful

acceptance and implementation at the higher levels of an

organization will directly impact the acceptance and consistent

usage of engineering controls at the employee level.

6. Summary

Developing collaborations or partnerships, procedures, implementation plans, design strategies, and case studies was the PtD

approach for reducing exposure of continuous mining machine

operators. NIOSH PRL policy was to take the leadership role and

present financial incentives to the manufacturers and sound

research to MSHA for updating the Program Information Bulletin

(PIB) P04-18, which would provide information about promising

and feasible engineering noise controls.

All representatives of the Coal Noise Partnership understood

their role. The key was getting upper management of the

manufacturer to buy into the benefits of the downstream users,

which in turn would benefit them in a long term. Having the

regulatory/enforcement arm of the government, MSHA, being
part of the Coal Noise Partnership was also a key in having upper

management of the manufacturer to buy in, knowing that MSHA

was serious about enforcing the regulations. In addition, since

the manufacturer had such a large percentage of the market

they understood that if MHSA would enforce the regulations

then the mining companies had to purchase the noise control.Joy

Mining Machinery has provided an initial investment of onemillion dollars for a new chain facility in pursing a “quiet-bydesign” approach for continuous mining machine chains. The

PtD method was successfully utilized to develop a noise control

for the conveyor of a Joy Mining Machinery continuous mining

machine. However, introduction and implementation of engineering controls in the workplace needs to consider the

organizational issue that intersects across management, safety,

training, and maintenance departments in an organization. The

impact of successful acceptance and implementation with

management of mining companies and mining machine manufacturers will directly impact the acceptance and consistent

usage of engineering controls at the employee level.

References

Kovalchik, P., Johnson, M., Burdisso, R., Duda, F., & Durr, M. (2002). A Noise

Control for Continuous Miners. Proceedings from the10th International

Meeting on Low Frequency Noise and Vibration and its Control, York

England (pp. 302). September 11 13, 2002.

U.S. Department of Labor Bureau of Labor Statistics. (2006a, May). web site

http://www.bls.gov/iif/oshwc/osh/os/osnr0025.txt

U.S. Department of Labor Bureau of Labor Statistics. (2006b, May). web site

http://www.bls.gov/oes/current/oes475041.htm

U.S. Department of Labor, Mine Safety and Health Administration. (2008). web

site ttp://www.msha.gov/30CFR/62.130.htm

U.S. Department of Labor, Mine Safety and Health Administration (2005).

Form 7000-2, Quarterly Mine Employment and Coal Production Report,

2005 web site http://www.eia.doe.gov/cneaf/coal/page/acr/table1.html

U.S. Department of Labor, Mine Safety and Health Administration. (2000 2005).

Title 30 CFR Parts 60. Denver, CO: Information Resource Center.

U.S. Department of Labor, Mine Safety and Health Administration.(1999).

Program Information Bulletin PO4-18. web site http://www.msha.gov/

1999noise/noise.htm

Peter G. Kovalchik General engineer and team leader of the noise control

team in the Hearing Loss and Prevention Branch (HLPB) at the National

Institute for Occupational Safety and Health (NIOSH), Pittsburgh Research

Laboratory. Mr. Kovalchik earned his B.S. in Mining Engineering at the

University of Pittsburgh (1983). Current research focuses on developing and

applying noise treatments to underground mining equipment that cause noise

overexposure. Past research focused on electrical safety issues in underground

mines.

Rudy J. Matetic Supervisory general engineer and branch chief of the Hearing

Loss and Prevention Branch (HLPB) at the National Institute for Occupational

Safety and Health (NIOSH), Pittsburgh Research Laboratory. Dr. Matetic

received his B.S. in Mining Engineering from Pennsylvania State University

(1983), M.S. in Civil Engineering from the University of Pittsburgh (1992), and

Ph.D. from West Virginia University (2005). Current research focuses on hearing

loss prevention through noise control technology, personal protective equipment,

worker empowerment, and speech/signal perception in noise. Past research

focused on mining equipment hazards, ground control and rock mechanics

Adam K. Smith Mechanical Engineer and member of the noise control team

in the Hearing Loss and Prevention Branch (HLPB) at the National Institute for

Occupational Safety and Health (NIOSH), Pittsburgh Research Laboratory.

Mr. Smith received his M.S. and B.S. in Mechanical Engineering from the

University of Pittsburgh (2003, 2005). Currently, he is the project leader for

research focused on reduces noise emitted by continuous mining machines. Past

research focused on adaptive filters used for active noise control algorithms and

vibration suppression of freight railroad cars.

Susan B. Bealko Mining Engineer with the National Institute for Occupational

Safety and Safety and Health (NIOSH) is involved in many fields of mining

research including ground control, ventilation, ergonomics, hearing loss, and

emergency response. Prior to joining NIOSH, she was employed by CONSOL PA

Coal Company as a Production Employee, Fireboss, and Mining/Industrial

Engineer. She has a B.S. in Mineral Engineering from The Pennsylvania State

University (1994), an M.S. in Safety and Environmental Management from West

Virginia University (2000), and an MPH in Environmental and Occupational

Health from the University of Pittsburgh (2007). Her current research focuses on

developing a worker exposure database for prioritizing noise control technologies.