No. 539 December 2009 

Identifying the Benefits of Engineering Noise Controls 

Through a Business Case 

Objective 

To develop a business case that promotes adoption of noise 

controls by reducing barriers to industry acceptance and enhancing drivers that foster their implementation. 

Background 

Over 75% of the U.S. mining workforce is exposed to 

hazardous noise, putting them at risk of noise-induced hearing 

loss (NIHL). Consequently, coal miners suffer high rates of 

hearing impairment that increase to 70%–90% by retirement 

age. To address the noise problem for coal miners, researchers 

from the National Institute for Occupational Safety and Health 

(NIOSH) first determined that the continuous mining machine 

(CMM) ranked first among machines associated with reported 

coal noise overexposures. Further studies found that most CMM 

noise is generated by three component systems on the machine: 

dust collection, cutting, and conveying. Of these systems, the 

on-board chain conveyor was found to be a dominant noise 

source. Noise generated by the conveying system was addressed 

through the development of a urethane-coated flight bar chain. 

The coated chain, shown in Figure 1, has demonstrated an 

8-hour time-weighted average (TWA) reduction of operator 

exposure by 3 dB(A).

 Figure 1.—Urethane-coated flight bar chain used in the conveyor system for a continuous mining machine. 

 It has since been accepted by the Mine 

Safety and Health Administration (MSHA) as a “technologically 

achievable” noise control for CMM operators who are exposed 

to noise that exceeds the MSHA permissible exposure level. 

Having demonstrated the noise reduction performance of the 

coated chain, NIOSH has assembled information into a business 

case that can be used by operations considering adopting the 

chain at their worksite. 

Business Case 

A business case is often used in organizations to assist 

rational decision-making about major initiatives. It facilitates 

systematic consideration of financial, organizational, and market 

perspectives. For occupational health and safety initiatives 

involving control technologies, a business case can encompass 

financial and organizational concerns alongside long-term 

health and safety outcomes. Although NIOSH and its partners 

have developed control technologies to reduce mine workers’ 

overexposure to noise, implementation at the workplace has 

been impeded by slow industry acceptance and buy-in. Some of 

the slowness is due to a lack of readily available information 

needed to move forward with implementation. In some cases, 

there are real or perceived barriers. These are addressed below, 

followed by several drivers that can accelerate implementation 

of noise controls. 

Barriers 

Financial expense: The perception that a noise control will 

increase costs is often used to defer investment in a control that 

might otherwise reduce health and safety risks. NIOSH worked 

with its industry partners when developing the coated chain to 

minimize any cost premium. The urethane-coated 38-inch conveyor chain produced by industry partner Cincinnati Mine 

Machinery costs 46% more than a standard single-sprocket 
chain. As demand and sales increase, the additional production 

volume may allow the company to reduce the cost further until 

it is comparable to that of a standard chain. These cost differences may be offset through long-term gains in lowered 

workers’ compensation costs and insurance premiums related to 

noise-induced hearing loss. 

Unfamiliar maintenance: The negative perception of new 

or different maintenance procedures may inhibit companies 

from switching chains. In working with the chain manufacturer, 

NIOSH found that the urethane-coated chain does not require 

any new or unusual maintenance procedures that differ from the 

manufacturer’s standard processes. Adhering to standard maintenance procedures (e.g., ensuring chain tension) will keep the 

urethane coating from wearing prematurely. 

Unfamiliar installation: Even though the urethane-coated 

chain will fit on any CMM that has a standard 38- or 30-inch 

conveyor system, there may be a perception that chain installation will change. During field testing, NIOSH research found 

there were no differences between installing a standard or a 

coated chain. The urethane-coated flight bar chains are engineered as a direct replacement that requires no modification of 

the machine. 

Variable conditions: Coal mine conditions can be highly 

variable, and there may be concerns that the urethane-coated 

chain cannot hold up in the more extreme conditions. To address 

these concerns, the coated chain was tested in the harshest 

conditions that could be found. It was placed in construction 

development and production sections that encounter exceptionally 

high wear and impact loads, including mining and conveying 

solid rock and construction debris. The coated chain worked 

successfully in these sections despite the harsh conditions. 

Durability: New technologies or equipment often prompt 

questions about whether they are as durable as the current 

technology or equipment. For the urethane-coated chain, these 

questions centered on whether it has the same chain life as a 

standard single-sprocket, noncoated chain. The coated chain was 

field-tested in three U.S. mines in a wide variety of mining 

conditions. At these mines, the urethane-coated chain had the 

same replacement rate as the standard noncoated chain, meeting 

or exceeding the mines’ expectations. 

Drivers 

Safety: Studies that investigated the link between noise and 

safety have found that workers whose daily noise exposures 

exceed 90 dB(A) have higher rates of single and multiple 

accidents. The risk is elevated for workers with normal hearing 

and is even higher for workers who have a hearing loss. Noise 

controls like the urethane-coated chain that reduce noise exposure can therefore also have a safety benefit. 

Lower noise exposure: Another form of risk is the increased likelihood of a noise-induced hearing handicap or 

impairment. A NIOSH-developed model shows that a 65-yearold worker with 10 or more years of exposure will have a higher 

likelihood of a hearing impairment with higher average noise 

exposures (Table 1).

Table 1.—Excess risk of hearing impairment based on 

8-hr time-weighted average sound level 

8-hr TWA, Excess risk of 

dB(A) hearing impairment, % 

80 1.2 

85 7.7 

90 22.3 

94 33.3 

95 38.3 

100 44.0

 So, for example, if the exposure can be 

reduced from 94 to 90 dB(A), 11 fewer workers out of 100 

would acquire a noise-induced hearing impairment. 

Lower stress: Reducing the noise exposure of CMM 

operators through the use of a urethane-coated chain will have 

an added benefit of lower workplace stress. Noise has been 

found to be a stressor that can interfere with concentration, 

causing errors and accidents. Stress is also linked to certain 

illnesses that can worsen absenteeism, reduce productivity, and 

increase insurance costs. 

Lower workers’ compensation costs: Workers’ compensation insurance provides financial reparation to workers who 

sustain workplace injuries, fatalities, and occupational disease. 

The insurance companies make payments to the affected workers while the mining companies pay premiums to the insurers. 

The premiums a company has to pay can be indirectly affected 

by claims experience, along with other factors. During 2006– 

2009, the two most recognized workers’ compensation insurance carriers for the U.S. coal mining industry received 

92 claims filed for (nontraumatic) hearing loss compensation. 

Together, they paid nearly $750,000 in hearing loss claims. 

Summary 

The goal of this research is to reduce mine workers’ overexposure to noise and ultimately reduce the number of workers 

who suffer from NIHL. Using a business case model can 

overcome the barriers and concerns that delay industry 

acceptance and use of control technologies such as the urethanecoated chain. The coated chain is part of a suite of controls 

developed by NIOSH and others that can reduce worker overexposure to noise. By assembling information into a business 

case model to challenge the barriers to industry acceptance, 

NIOSH is working to promote adoption of effective engineering 

noise controls. 

For More Information 

For more information on using a business case model to 

promote the adoption of engineering noise controls, contact 

Dana C. Reinke, Ph.D. (412-386-5348, DReinke@cdc.gov), 

Adam K. Smith (412-386-6028, ASmith9@cdc.gov), or the 

Health Communications Coordinator (OMSHR@cdc.gov), 

NIOSH Office of Mine Safety and Health Research, P.O. Box 

18070, Pittsburgh, PA 15236-0070. 

To receive NIOSH documents or for more information 

about occupational safety and health topics, contact: 

1-800-CDC-INFO (1-800-232-4636), 1-888-232-6348 

(TTY), e-mail: cdcinfo@cdc.gov, or visit the NIOSH 

Web site at http://www.cdc.gov/niosh 

Mention of any company name or product does not 

constitute endorsement by the National Institute for 

Occupational Safety and Health. 

DHHS (NIOSH) Publication No. 2010–121