Mine operators (left), NIOSH researchers (middle) and Virginia 

DMME trainers (right) talk about how the CPDM has been used 

to identify and reduce exposure to respirable coal dust.

Photo provided by Virginia DMME.

How Miners in Low Coal

Respond to the CPDM

by Emily Haas, and Justin Helton, National Institute for Occupational Safety and Health, Pittsburgh, PA 

As the relatively new respirable 

dust regulation (30 CFR Part 70) 

completes its phase-in process at 

coal mines, we still have much to 

learn about the challenges of maintaining 

compliance and controlling dust sources. 

Beginning on February 1, 2016, coal 

mine operators were required to begin 

collecting respirable dust samples using 

continuous personal dust monitors 

(CPDMs) for designated occupations 

(DO) and “other” designated occupations 

(ODO). On August 1, 2016, the maximum 

allowable concentration limits for DOs 

and ODOs at the working face were 

reduced to 1.5 mg/m3. During this time 

frame, National Institute for Occupational 

Safety and Health (NIOSH) researchers 

have been studying the response to and 

application of this technology from various 

viewpoints. Recently, NIOSH completed 

a series of low-seam coal mine visits in 

cooperation with the Virginia Department 

of Mines, Minerals and Energy. The goal 

of these visits was to understand what 

unique challenges may exist for those 

DO and ODO miners who are required to 

use the CPDM while working in low coal 

(approximately 43 inches) (Mine Safety 

and Health Administration [MSHA], 

2009), in comparison to miners who work 

in coal seams over 60 inches. 

In 2015, 305 underground coal mines 

produced 306,821,000 tons of coal 

(US Energy Information Administration, 

2015), of which approximately 15% 

was mined in seams under 43 inches. 

It is widely acknowledged that miners 

who work in low-seam operations face 

different challenges than those who 

operate in a seam that allows them to 

stand and offers more mobility. Mainly, 

continuous mining operators (CMOs) and 

roof bolters, both falling within the DO or 

ODO categories, spend their shifts in 

kneeling and squatting postures (NIOSH, 

2011). Further, the CPDM worn on the 

miners’ belts (per 30 CFR Part 74.7) 

adds 2 kg to the weight being carried 

and could be more difficult to read in a 

crouched position, so the question arises 

as to how these low-seam coal miners 

will perceive this technology. 

To examine this issue, NIOSH asked 

miners, mine operators, and dust 

technicians various questions about 

individual worker and organizational 

responses to the CPDM as it became 

part of their job. Some of the primary 

findings are discussed to allow 

industry stakeholders and technology 

manufacturers to consider this sometimes 

forgotten, yet significant group of miners 

when designing and tweaking similar 

technologies. 

Challenges with Confined Space 

and Mobility 

As expected, miners who work in lowseam coal shared their frustrations with 

the additional ergonomic challenges 

that the CPDM introduces into their 

workday. Those miners who are smaller 

in stature have an even harder time 

fitting the CPDM around their miners’ belt 

while also wearing their self-contained 

self-rescuer (SCSR), proximity PWD, 

and other required tools. Also, in some 

situations roof bolters cannot wear the 

CPDM while pinning; rather, they have to 

put it on the bolting machine’s platform. 

Similarly, shuttle car operators (SCOs) 

have difficulties loading with the CPDM 

on their belt. Since there is not enough 

room on the deck and the roof is too low 

for canopies, they tend to set the CPDM 

next to them on their seat. However, in 

the shuttle car, the noise and vibration 

can sometimes affect the operation of 

the CPDM. Similarly, CMOs mentioned 

the difficulties they have navigating and 

moving around in low seams with bulky 

objects around their neck and waist, 

such as their remote miner controller, the 

42 Mining People Magazine www.miningpeople.org
APRIL / MAY Issue 43

CPDM, and SCSR. 

Acknowledging these mobility and space 

constraints, many low-seam miners

who NIOSH talked with said they were 

hesitant to change their work practices 

even to avoid dust exposure. One 

CMO said, “I know I should move but I 

just don’t because it’s pretty difficult to 

resituate and still do my job.” One CMO 

went into more detail when he discussed 

a scenario that he knows exposes him to 

higher levels of coal dust:

“The water sprays are good, but when 

coal is being loaded off of the conveyor 

onto the boom you have to run and even 

with the water on there’s a good bit of 

dust. You have to move back. But for 

us that means we roll or crawl. It’s very 

tough. You just can’t crawl in time. It’s 

easier to react when you’re standing. 

Just remember, low coal people are 

less apt to move. We stay in one spot.”

CMOs and roof bolters also discussed 

times that they stayed in one spot to 

avoid any technical problems with the 

CPDM. They relayed problems with their 

CPDM hoses crimping or tearing as a 

result of movement, which can lead to 

the CPDM registering a “status code” 

and the sample potentially being voided 

by MSHA after examining the CPDM 

data file and use criteria. A similar issue 

was discussed with the lapel piece of 

the CPDM being covered when they 

changed positions. Miners said that if 

anything goes over the lapel opening 

for a prolonged period of time (around 

two minutes), the CPDM again would 

register a status code and potentially 

void the sample. With no alerts to warn 

miners that their hose is crimped or the 

lapel is covered, they are often unaware 

that they need to change their position. 

After replacing torn hoses or having to 

wear the CPDM for an additional number 

of days, miners said that they were more 

apt to stay in one place to avoid any 

CPDM-related sampling problems. 

To maintain normal mobility at these lowseam mines during CPDM sampling, a 

common compromise for miners was to 

have their SCSR within 25 feet of where 

they were working in order to comply 

with regulations, noting that wearing the 

SCSR and CPDM at the same time made 

it unmanageable to crawl in the mine. 

These issues were faced by everyone 

when they first started wearing the CPDM. 

However, several miners eventually

opted to make a conscious effort to teach 

themselves and make changes based 

on the CPDM after seeing higher-thanexpected dust data readouts, albeit still 

within compliance.

Miners Taking Control to Reduce 

Dust Sources

A majority of miners noted that they 

checked their CPDM periodically, but not 

every 15 or 30 minutes. As one miner 

said, “Basically just the concentration 

for the shift and comparing it to the limit. 

But, I have to operate the miner a certain 

way in a certain position anyway. CMOs 

have little control here.” However, a 

CMO at one of the low-seam locations 

was able to make changes using this 

device. A dust technician said, “I showed 

him his initial readings with the CPDM 

that were over 1.0 mg/m3 because we 

don’t want anything over 1.0 mg/m3. 

He experimented with it and he moved 

himself to different areas. He’s in a better 

range now, he learned a lot, and he feels 

better.” Those miners who tested their 

exposures in different areas and checked 

the display concentrations noted that, 

even though it was hard to react in the 

moment due to their mine environment, 

they were able to be more proactive the 

next day when they knew a task was 

approaching that would result in higher 

dust exposure.

Additionally, roof bolters were able to learn 

about their biggest dust sources and take 

steps to reduce unnecessary exposures 

throughout the workday. For roof bolters, 

cleaning the dust boxes upwind is a 

common, well-known dust-producing 

task. Accordingly, organizations have 

changed work practices after seeing just 

how high exposure peaks for roof bolters 

can be on their dust data readouts. Now, 

roof bolters alternate changing bags so 

that one person is not getting all of the 

unavoidable dust exposure. Although 

this may sound like an intuitive work 

practice, many miners indicated that they 

became more aware of tasks within their 

daily routine that produce higher levels 

of dust through their CPDM readings 

and, consequently, altered their work 

practices. 

Finally, miners discussed the role

of the CPDM in revealing specific

circumstances in their mine that are 

critically important to controlling their dust 

exposure. They discussed things such as 

tight line curtains, adequate ventilation, 

and ample water pressure as having the 

biggest impact on their health throughout 

the workday. As one miner said, “You 

are always producing a dust cloud. So 

you move when you can whether it’s out 

of the dust or across the intake where 

there’s not as much pressure.”

The Role of Management in 

Facilitating and Maintaining Dustreducing Practices

NIOSH heard from members of mine 

management about their experiences 

with encouraging and trying to maintain 

work practices that minimize exposure 

to respirable dust. First, many mines 

took the initiative to send all of their 

employees to the CPDM training at 

a local MSHA district office so they 

could better understand the capabilities 

and limitations of the technology. This 

action also granted every employee a 

certification to run the CPDMs. Managers 

felt that providing this extra background 

knowledge to employees helped build 

overall dust awareness within their 

workforce. 

In addition, managers and dust 

technicians discussed what they learned 

about dust exposure of ODOs (e.g., 

positions other than the CMO). One 

individual said:

The roof bolter is at a bigger risk for black 

lung than the CMO. The problem is that 

the CMOs, they got black lung hammered 

into them and the dangers of it. They’re 

more aware. We’ve left the roof bolters 

behind, haven’t paid the attention to their 

health that’s been needed. And of course 

for the roof bolters their risk is more 

silicosis, which is worse than black lung. 

This individual continued, reflecting that 

his company is doing a much better 

job at keeping the roof bolter out of the 

return than in the past, based on the 

CPDM data. Although the dual ventilation 

system at many sites helps minimize 

exposure, he said it is imperative to 

work with roof bolters to change their 

initial drilling practices. Specificall , when 

they first start drilling into the first four 

inches of the roof, the drill suction gets 

clogged, which blows a large amount of 

dust out once the obstruction is cleared. 

To minimize dust liberation from clogged 

drills, management said that drilling the 

first four inches more slowly is crucial. 

Several managers discussed relaying 

this message to their bolters to help 

reduce their exposure to respirable dust. 

Ultimately, using the CPDMs has 

allowed members of management to 

communicate more readily with at-risk 

continue
CPDM continued

groups based on miners÷ attitudes toward 

coal dust exposure. It was common for 

managers to say that, at flrst, everyone 

liked to look at their dust data readouts. 

If they asked miners why they had a 

peak at a speciflc time, most were able 

to remember if the incident was recent. 

However, three issues are readily 

apparent based on the discussions with 

managers. Firstly, miners experience 

complacency after reading and analyzing 

so many dust data cards and become 

less interested in time. Secondly, after 

initial behavioral changes, they may feel 

unable to make further modiflcations 

without impacting their job further. Finally, 

it is critical to motivate younger workers 

to care about their exposure to respirable 

dust and educate them about its longterm health effects. 

Managers also said that nonconfrontational discussions about any 

readouts that are over 1.0 mg/m3 are 

important. Additionally, they said that 

asking their workforce about what the 

flnal number over an 8-hour period 

means is imperative to help support the 

maintenance of behaviors during times 

when they are not required to wear the 

CPDM. As one manager said, ”It÷s a 

culture. I think they÷re changing behavior 

for health reasons and compliance 

reasons. Even though it÷s a little of 

both I just want it to be maintained.‘ 

Therefore, even if day-to-day processes 

do not or cannot change very much due 

to the constraints in low-seam mines, 

the communication and support offered 

by management through education 

about their dust readouts can help 

support a slow shift in perceptions. This 

could eventually empower and sustain 

routine practices that may be viewed as 

daunting among workers right now, such 

as crawling, rolling, and slowing down 

practices. 

Moving Forward with the CPDM

With these beneflts and challenges in 

mind, it is clear that these low-seam 

miners, like other miners, appreciate 

the real-time dust information. It was 

common for operators to re‡ect back 

on times that they received a notice that 

they÷d had a bad sample 30 days earlier 

and had no idea what they were doing at 

that time. The ability to know exposures 

in real-time has empowered health 

and safety practitioners in the industry. 

However, there are also barriers faced 

in low-seam mines that further impede 

miners÷ abilities to respond accordingly. 

First, to avoid any voided samples due 

to crawling or moving, most miners noted 

that they would rather stay in one spot 

than risk starting their sampling period 

all over again. Continuing to tweak the 

technology to meet the constraints of 

this speciflc environment and spending 

more time understanding the differences 

among low-seam miners÷ work tasks 

could help improve the design of the 

technology and support this group of 

workers in modifying some of their 

practices. Second, several managers 

and miners expressed concerns about 

the CPDM taking attention away from 

their work task due to nervousness 

about compliance. In response, while 

getting used to what the CPDM dust data 

means, miners labeled the technology 

as an unintentional hazard on the job. 

Continued participation in the CPDM 

certiflcation trainings may help minimize 

any questions and doubts miners have 

on the job when looking at their real-time 

dust levels. However, even if knowledge 

and awareness are high among the 

workforce, maintaining the knowledge 

that any dust exposure is harmful will be 

important to continually reduce personal 

dust sources. 

Although there is still a learning curve 

about what impact this technology is 

having on healthier work practices within 

the mining industry, highlighting the 

interactions of an often forgotten group 

is essential to enhance understanding. 

Moving forward, flnding a balance of 

healthy work practices and compliant 

work practices is important. Looking 

past the initial technological and 

environmental hurdles in obtaining 15 

good samples, the industry recognizes 

the importance of the information this 

technology can offer. As one miner said, 

”I think this has helped us stay out of the 

dust. It÷s just hard when you have a bad 

day.‘

Disclaimer: The flndings and conclusions in this paper are 

those of the authors and do not necessarily represent the 

views of the National Institute for Occupational Safety and 

Health (NIOSH). Mention of any company or product does not 

constitute endorsement by NIOSH.

References: Code of Federal Regulations (30 CFR Part 70). 

Lowering Miners÷ Exposure to Respirable Coal Mine Dust 

Including Continuous Personal Dust Monitors. Mine Safety 

and Health Administration, Department of Labor. RIN 1219-

AB64. 

Code of Federal Regulations (30 CFR Part 74.7). Design 

and Construction Requirements for Coal Mine Dust Sampling 

Devices. Mine Safety and Health Administration, Department 

of Labor. 

Energy Information Administration (2015). Annual Coal Report 

2015. Independent statistics and analysis. US Department of 

Energy, Washington, DC. Retrieved from www.eia.gov.

MSHA (2009). Accident, illness and injury and employment 

self-extracting flles (Part 50 Date). US Department of Labor, 

Mine Safety and Health Administration, Offlce of Injury and 

Employment Information, Denver, CO. https://arlweb.msha.

gov/STATS/part50/. 

NIOSH (2011). Demands on the knee during kneeling and 

squatting activities common to low-seam mining. Department 

of Health and Human Services, Public Health Service, 

Centers for Disease Control and Prevention, National Institute 

for Occupational Safety and Health, Pub No. 2011-176, RI 

9681; 1-47.

44 Mining People Magazine www.miningpeople.org