Miners’ Views about Personal Dust Monitors 


Robert H. Peters, Charles Vaught, Erica E. Hall, and Jon C. Volkwein 

Pittsburgh Research Laboratory, National Institute for Occupational Safety and Health, 

626 Cochrans Mill Road, Pittsburgh, PA 15236 

ABSTRACT 

oal Workers Pneumoconiosis is the leading cause of death due to occupational illness among coal Cminers. This disease is caused by miners’ exposure to respirable coal mine dust. A Personal Dust 

Monitor has recently been developed to provide near real time feedback to miners regarding the number 

of milligrams of respirable coal mine dust in the air they breathe. This paper was prepared by the National 

Institute for Occupational Safety and Health to document coal miners’ reactions to this new device, and 

how they make use of the information it provides. Structured interviews were conducted with 30 coal 

miners at four mines. A four-stage conceptual model of miners’ decision processes with respect to how 

they interpret and respond to the dust exposure numbers from their personal dust monitor is proposed. 

The stages are: Diagnosis, Action Planning and Intervention, Evaluation, and Institutionalization. The 

interview responses provide considerable support for the model. Most miners paid attention to Personal 

Dust Monitor feedback and made efforts to reduce their dust exposure. Their efforts included: changing 

where they positioned themselves, making ventilation system improvements, and using respirators more 

often. The 29 miners who reported having experience wearing both the old and new type of dust monitors 

were asked which dust sampling system they preferred. Eighteen (62%) preferred the new monitors, 7 

(24%) preferred existing monitors, and 4 (14%) had no preference. The most frequently cited advantage 

of the new monitor is its ability to provide relatively quick feedback on dust exposure. Miners provided 

several suggestions for improving the design of the instrument. 

Keywords: Black Lung disease, Coal mine dust, Underground mining, Pneumoconiosis, Exposure 

assessment, Effectiveness research, Respiratory disease, Work practices 

INTRODUCTION 

lthough the most recent data on the prevalence of Coal Workers’ Pneumoconiosis (CWP) in the AUnited States indicates that it is declining, substantial numbers of CWP cases continue to be 

diagnosed (Antao et al. 2006; Antao et al. 2005; Pon et al. 2003). During the three year period, 2000 – 

2002, CWP contributed to the deaths of 2,697 miners in the US (US Dept. of Health and Human Services, 

2005). In 2004, Federal “Black Lung” benefits totaling more than $726 million were paid to approximately 

93,000 beneficiaries [US Dept. of Labor, 2007]. Data from MSHA indicate that from the early 1980s to 

2006 the underground coal mining industry experienced little change in level of exposure to respirable 

coal mine dust [US Dept. of Labor, Mine Safety and Health Administration, 1982-2006]. In 1982, the 

mean value based on 86,000 samples from mine operators was 1.0 mg. In 2006, the mean value based 

on 26,000 samples from operators was 0.9 mg. During the period 1995 to 2006, 12% (40,790) of 

operator-collected designated occupation samples (337,066) and 15% (7,039) of MSHA inspector 

samples (47,966) exceeded the applicable dust standard. 

A Personal Dust Monitor (PDM) has recently been developed through a collaboration involving 

NIOSH, the Bituminous Coal Operators’ Association, the United Mine Workers of America, the National 
 

Mining Association, Thermo Fisher Scientific Inc. and the Mine Safety and Health Administration (Figures 

1 and 2). This new device represents a major advance in the tools available for assessing coal miners’ 

exposure to respirable dust levels. 

Figure 1. A miner wearing the PDM. 

Power Takeoff 

Display 

and Buttons 

Block with 

Flow Sensor Orifice 

Temp and RH 

Cap Lamp 

Cyclon 

TEOM 

Mass Sensor 

Air heater 

Sample filter 

Pump 

Sample 

Inlet 	 Air/ Electrical 

Umbilical Cable 

Cap Lamp 

Battery (Left) 

TEOM System 

Battery (Right) 

Figure 2. PDM internal components.
 
To date, the dust monitoring process has relied upon a coal mine dust personal sampler unit to 

collect a filter sample in the mine environment. The respirable dust-laden filter is then sent to a laboratory 

for analysis. Results are returned to the mine operators several days after the actual samples were taken. 

A major advantage of the new PDM is its ability to provide near-real-time dust exposure data. This 

feedback allows miners to better understand how their actions are related to variations in dust exposure, 

and tells management how actions and equipment affect each miner’s dust exposure. The new PDM has 

been field tested at 10 mines, and found to be at least as accurate as samplers currently in use (Volkwein 

et al. 2006). As with the introduction of any new technology, it is very important to systematically 

document how workers react to it and make use of it. If miners know how to properly use the information 

PDMs are capable of providing, they may be able to make adjustments to their work place or work 

procedures that will reduce their exposure to respirable coal mine dust. There appears to be great 

potential. However, no one knows precisely how miners performing a wide variety of tasks and jobs are 

actually going to use this new information to reduce their exposure to dust. 

By collecting and sharing information about how miners have begun to use PDMs, we hope to 

facilitate the effective use of this new technology to help prevent Black Lung disease. This paper provides 

examples of how miners used PDM information to diagnose the causes of exposure to high levels of 

respirable dust, and make changes to try to reduce their exposure. This paper also documents the 

opinions of a small number of mine safety directors and their staff, who maintained the equipment for four 

weeks. The findings from interviews with 30 miners and seven mine safety staff members are presented. 

METHODS 

PDMs and training materials were delivered to the mine’s safety director at least 10 days before 

miners began wearing PDMs. After becoming familiar with the dust monitoring system and the 

instructional materials, the safety director provided training to a crew of miners. The 30 minute training 

session consisted of showing a six minute training video, followed by a period of questions and answers. 

At the end of the class, miners were asked to complete a short questionnaire to evaluate their 

understanding and retention of information about PDMs. Miners then wore their PDMs each shift for four 

weeks. Researchers returned at the end of the fourth week to interview the miners and the persons in the 

safety department who had maintained the PDM equipment and kept records of the dust exposure data. 

The interview questions were intended to yield the following types of information: (1) descriptions 

of incidents in which miners tried to use their PDM to reduce their dust exposure; (2) problems or 

difficulties encountered by miners while wearing the PDMs; (3) problems or difficulties encountered with 

maintaining the PDMs and the data they provide; and (4) evidence regarding the validity of a conceptual 

model proposed to explain how PDM feedback leads to changes in miners’ behavior and to reduced dust 

exposure. 

All miners who wore a PDM during the preceding month, and who were present on the day that 

the interviewers visited the mine, were asked to participate in an interview. All interviews were conducted 

in private, usually at a dinner area near the miner's work site. All participants were assured that their 

responses would be held in confidence and were told that their participation was completely voluntary. No 

one refused to participate in the interviews. Each interview lasted approximately 20 to 30 minutes. All 

interview questions had been reviewed and approved by the NIOSH Human Subjects Review Board and 

the Office of Management and Budget (OMB). The complete list of interview questions can be found in 

Appendix A and a NIOSH Information Circular Report (Peters et al. 2008). 

Data were collected from September 2006 to May 2007. A total of 30 miners from four 

underground coal mines participated in the interviews. The mines were selected jointly by NIOSH and by 

the coal company officials who participate in a PDM research partnership committee. Table I presents 

information about each of the four mines including: the number of miners interviewed, the number of 

underground employees, the location, the seam height, and whether or not miners were represented by a 

union. The sample is composed primarily of large mines operating in relatively high seams. The mines 

were located in Utah and West Virginia. 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Table I. Sample Mine Characteristics 

 �����������������������������������������������������

 Number of Number of Seam 

miners underground height 

Mine interviewed employees Location (in) Union 

 �����������������������������������������������������

 A 5 255 Utah 102 Yes 

B 6 439 North WV 72-84 Yes 

C 10 81 South WV 66-76 No 

D 9 125 South WV 54 No 

 ����������������������������������������������������� 

Half of the mines were represented by a union and half were non-union. Mine C used only 

continuous mining machinery to extract the coal. The other mines were using longwall mining equipment 

in addition to continuous mining machines. The crews in mines C and D were operating a “supersection” 

i.e., two continuous mining machines (rather than one) were being used in the section where miners were 

wearing the PDMs. 

RESULTS AND DISCUSSION 

Characteristics of miners’ interviewed. Miners were asked what job they currently performed, and 

how much mining experience they had. Table II lists their jobs. 

 Table II. Breakdown of Mine Employees Interviewed, by Job Title 

 ����������������������������������������������
 

Number 


 Shuttle car operator 5 


 Continuous miner operator 5 


 Longwall shearer operator 2 


 Longwall jack setter 3 


 Roof bolter operator 8 


 Mechanic 2 


 Electrician 1 


 Scoop operator 1 


 Section foreman 2 


 Face man 1
 

Total 30 


 ����������������������������������������������
 
 

 

 

Most miners had substantial experience working as a coal miner. Nineteen had more than 10 

years of experience. Only one had less than 2 years of experience. All but three miners had worked in 

their present job category for more than a year. Miners’ ages were distributed as follows: 

Age (yrs) N 

Less than 30 6 

30 – 39 6 

40 – 49 12 

50 and over 6 

The sample consists of miners with considerable mining experience, and who represent all the 

major categories of jobs performed in face areas of underground coal mines in the United States. 

Miners’ Interpretation and Response to PDM Feedback 

Figure 3 proposes a four-stage conceptual model of miners’ decision processes with respect to 

how they interpret and respond to the dust exposure numbers from their PDM. The model is based on a 

few different lines of psychological research including the health belief model (Janz and Becker, 1984; 

Janz et al. 2002), self-efficacy (Bandura, 1977; 2004) and studies on feedback interventions (Kluger and 

DeNisi, 1996). The four stages of the model are: Diagnosis, Action Planning and Intervention, Evaluation, 

and Institutionalization. Each stage is described below, and miners’ responses to interview questions 

relating to Stages 1, 2 and 3 are summarized. 

Stage 1. Stage 2. Stage 3. Stage 4. 

DIAGNOSIS ACTION PLANNING EVALUATION INSTITUTION­

& INTERVENTION ALIZATION 

Do I have 

feasible ideas 

for eliminating 

the source? 

Implement 

change 

Reduces 

dust 

Doesn’t 

reduce 

dust 

• Investigate 

 possibilities 

• Ask for help 

Ask for help 

• Avoid situation 

• Rotate jobs/ 

 Admin controls 

• Cognitively adjust 

goal 

Institutionalize 

the change Do I know the 

source(s) of 

my exposure? 

Figure 3. Conceptual model of how miners use PDM information. 

Stage I. Diagnosis 

The model starts with the assumption that the person wearing the PDM notices a number that is 

high enough to cause concern. The concept of cues that trigger action has been discussed in various 

early formulations of the Health Belief Model. Hochbaum (1958), for example, thought that readiness to 

take action (perceived susceptibility and perceived benefits) could only be potentiated by other factors, 

particularly by cues to instigate action, such as bodily events, or by environmental events, such as media 

publicity. 
 

 

 

 

 

Until now, miners’ cues to action relative to preventing CWP may have included: information from 

chest x-rays, advice or warnings from one’s doctor, physical discomfort in one’s lungs, coughing, 

shortness of breath, report of a high dust level from a previous days sampling, or a perception of high 

levels of dust in the mine air. CWP is an insidious health problem. It often takes years to develop, and 

miners may not receive any cues to warn them that respirable dust is damaging their lungs. Miners may 

not experience any physical symptoms to warn them that they are developing CWP until the later stages 

of the disease. Also, since the dust particles that cause CWP are invisible to the human eye, miners may 

sometimes be unaware that they are in the air they are breathing. 

The information from PDMs should serve as a very important cue to action. Wearing a PDM 

allows miners to see how their dust exposure varies throughout the course of their workday. They should 

soon learn what circumstances expose them to high dust. For example, once people who work on 

longwall crews begin wearing PDMs, they may realize that whenever they spend time inby the shearer, 

they are being exposed to respirable dust levels that are very high relative to being outby the shearer. 

Receiving near-real-time feedback about what causes high respirable dust exposure should help miners 

to become more cognizant of when they are in an unhealthy situation, and hopefully, to think about how 

they can reduce the amount of time they spend in those situations. 

Miners’ responses to interview questions pertaining to the Diagnosis Stage 

Miners were asked, “During a typical shift, how many times do you look at the numbers on your 

PDM?” Twenty-five miners gave numerical estimates ranging from 1 – 20. The median numerical 

estimate was 6 times. Five miners said they looked at it “frequently” or “several times”. 

Miners were given a response card and asked to select one of four options to answer the 

question: “Which option best describes how often you looked at your dust exposure number before you 

turned in your PDM at the end of the day?” Most miners said they looked at this number every day. The 

distribution of responses is as follows: 

Response Distribution


 every day 20 


most days 8 


a few days 1 


never 1 


Miners were reminded that their PDM has a few different screens with information about dust 

concentrations. The initial screen has values for MC0, CUM0 and PROJ. MC0 is the miner’s average 

respirable dust exposure during the past 30 minutes (expressed as number of milligrams per cubic 

meter). CUM0 is the miner’s cumulative respirable dust exposure since the shift began. Mathematically, 

CUM0 is the mass divided by volume sampled to the present point in time. The PROJ is the miner’s 

projected exposure for the whole shift. Mathematically, PROJ is the mass divided by the volume to be 

sampled for the entire shift. PROJ starts out as a very low number and steadily progresses to the true 

end of shift concentration. If CUM0 exceeds the permissible exposure limit, steps can be taken to reduce 

the miner’s exposure to stay within the permissible exposure limit before the end of the shift. However, 

once the limit (PROJ) is exceeded, it becomes impossible to meet the permissible exposure limit. 

Miners were given a response card and asked to select one of four options to answer the 

question: “How often did you look at this initial screen?” The distribution of responses is as follows: 

Response Distribution 


more than 3 times per day 20 


at least once per day 9 


a few times per week 0 


less than once per week 0 


Miners were next reminded that another screen on their PDM shows a bar chart. Each bar 

represents the average dust concentration for 30 minutes intervals since the beginning of the shift. Miners 
were given a response card and asked to select one of four options to answer the question: “How often 

did you look at the bar chart screen?” The distribution of responses is as follows: 

Response Distribution 


more than 3 times per day 20 


at least once per day 6 


a few times per week 3 


less than once per week 1 


Miners were asked, “Did you notice whether your numbers tended to fluctuate throughout the 

day?” Twenty-seven of 30 miners said “Yes”. Those who said “Yes” were next asked if it was usually clear 

to them what was making the numbers go up and down. All said “Yes”. Miners were asked, “Were you 

ever surprised or concerned by what the numbers on the PDM display were telling you?” Seventeen of 30 

said “Yes”. Those who said Yes were asked to recall the most recent time this happened, and to explain 

what they were doing when they noticed the unusual reading. The types of activities they mentioned 

were: 

Returning from tailgate on longwall 

Cutting coal with continuous miner 

Cutting rock with continuous miner 

Operating shields on longwall 

Riding the man trip 

Operating scoop in return

 Roof bolting 

All but one of these 17 miners said that they were surprised by how high the numbers on their 

PDM were. One miner who was cutting rock with a continuous mining machine said he was surprised 

because the numbers were not as high as he thought they would be. Given that miners will sometimes 

become aware that the level of respirable dust in their work environment is high, the conceptual model 

assumes that some are apt to start thinking about what is causing it. If they do not know what is causing 

the high respirable dust, they may investigate. For example, some of the miners in this study reported 

checking to see if the necessary ventilation controls were working properly. Perhaps water sprays on coal 

cutting machinery are not working or ventilation curtains are not properly installed. If they cannot find a 

plausible explanation, miners may ask others if they know why the respirable dust level is so high. 

Stage II. Action planning & intervention. 

Once miners think they have a plausible explanation for the high respirable dust, some are apt to 

start thinking about how to eliminate exposure to the source. If they think they can correct the problem on 

their own, they will hopefully take care of it. If they do not know how to eliminate the source, they may ask 

for help. If they do not have the time or resources needed to fix the problem, they may inform their 

supervisor. 

Miners’ responses to interview questions about Action Planning & Intervention Stage 

Miners were asked if they had tried to do anything to reduce their dust exposure. The following 

twenty-seven actions were reported: 

15 changed position 

 3 changed ventilation 

 4 changed both position and ventilation

 1 wore his respirator more often 
 Position. Continuous miner and longwall operators said they stood a few feet farther away from 

the dust. Roof bolter operators said they waited for the continuous miner to finish cutting before bolting. 

Shuttle car operators reported that they stayed behind the ventilation curtain in intake air longer. 

Ventilation. Miners reported keeping the ventilation curtains up closer to the face and keeping 

them tighter. 

 Respirators. One of the miners on the longwall said he began wearing a respirator during certain 

phases of his job. At a super section, the crew was told to wear respirators until air flow into the section 

could be increased. 

Stage III. Evaluation 

The next stage of the conceptual model is Evaluation. After making a change to try to reduce their 

exposure, miners may try to evaluate whether the change helped. One good way to do that would be to 

check the numbers on their PDM to see if they went down. 

If the change does not initially reduce respirable dust, they may try the same approach but more 

vigorously, or they may conclude that they really did not know the true source of the dust, or that a 

different type of countermeasure is needed. They may try to investigate other possible sources or 

countermeasures, or may seek help or advice from others. 

Miners may not always be able to maintain acceptable levels of dust exposure. Changes that are 

beyond their control may be needed, i.e., mine wide ventilation system changes. At one mine, several 

changes were attempted during the first two weeks of the field test, but dust levels were still too high. The 

safety director said the PDM data helped him convince mine managers that they must increase the 

volume of air flowing to this section of the mine. Thus PDM data can be a very useful decision tool for 

mine safety directors, managers and engineers, as well as for the miners. 

When high dust levels persist, miners may simply learn to avoid being in certain locations at 

certain times when they know respirable dust will be high. Or, it may be possible to reduce an individual’s 

daily exposure through administrative controls, such as having miners perform a different job for part of 

the day, i.e. one that does not expose them to as much dust as their primary job. 

Another way miners might respond to feedback about high respirable dust exposure is to 

cognitively adjust (upward) the perceived level of respirable dust they think they need to be concerned 

about. This will be discussed in greater detail below. After repeated failures, some miners may 

experience “learned helplessness”, and give up trying. Learned helplessness is “the experience of 

uncontrollable failure to solve a problem originally perceived as solvable.” (Mikulincer, 1994, p. 13). 

Taylor’s (1983) cognitive adaptation theory maintains that disconfirmation of efforts to control 

one’s health often do not produce the emotional upset or inactivity that one might expect based on 

reactance or learned helplessness theories. Rather, there are many things that can potentially be 

controlled, and if one’s need to control a situation is great, one will control what one can and give up 

attempting to control what one cannot. When a particular plan is thwarted, some alternative plan is often 

substituted to try to accomplish the same goal. This suggests that if a miner is truly concerned about 

contracting CWP, he or she is apt to try several different approaches to reducing respirable dust exposure 

before giving up. 

Until now, miners have never had quick access to information about their personal dust exposure. 

Therefore, it might have been easier for them to assume that the amount of respirable dust they were 

breathing was nothing to worry about. Because PDMs provide miners with relatively quick and objective 

evidence about their respirable dust exposure, miners may be less likely to harbor false illusions, i.e., that 

the air they are breathing is harmless when in fact it contains high levels of respirable dust. 

Miners’ responses to interview questions pertaining to Evaluation Stage 

Whenever miners reported making any changes to reduce their dust exposure, they were asked, 

“Did you look at the numbers on your PDM to see if they went down after you made this change?” In 22 

cases, miners said “Yes”. In all but two of these cases, the miner reported seeing the numbers go down 

following the change. In one case, the miner said that the change caused his numbers to stop rising. In 
 

 

 

 

another case, the miner said that the change did not seem to affect his numbers, but he thought that the 

change had helped reduce his coworker’s exposure, i.e., the continuous miner operator. 

For miners to be motivated to take precautionary measures to protect their health, the Health 

Belief Model suggests that they must believe the preventive actions will be effective in reducing their 

exposure to the hazard. To assess miners’ perceptions of the magnitude of the effect of their changes, 

they were asked to choose one of four options on a response card to answer the question, “Which option 

best describes how much you think this change will reduce your overall exposure to dust?” 

The distribution of responses is as follows: 

Response Distribution

 None 0 

Small 4 

 Moderate 16 

 Large 4 

This suggests that most of the miners believed the changes they made were efficacious in 

reducing their dust exposure. There is also some limited objective evidence that dust exposures declined 

following the introduction of PDMs. One of the mines that participated in the study allowed NIOSH access 

to the dust exposure data collected during the four weeks that their miners wore the PDMs. Analysis of 

the data confirmed that this mining crew’s exposure steadily declined throughout the month they were 

wearing PDMs. By the end of the test, their exposure had declined by about 60%. 

Second Samples. PDMs are designed to allow miners to quickly determine whether changes are 

effective in reducing respirable dust. By pressing two buttons on the PDM, miners can initiate a new 

“second sample” at any point in their work day. They will start to receive feedback within 15 minutes 

regarding whether or not the change they just made is reducing respirable dust. Miners can start/stop a 

second sample as often as they want. Starting a second sample does not affect the initially programmed 

sampling for the entire shift. 

During the interviews, miners were reminded that their PDM allows them to start taking a new 

“second sample” at any point during their shift. They were asked, “Did you ever try out the Second 

Sample feature on your PDM?” Relatively few miners (11 of 30) reported trying to use this feature. Of the 

11 who tried, most said they used it only once or twice. Miners may need additional instruction or 

encouragement to take advantage of the second sample capability. 

Stage IV. Institutionalization 

The final stage in the model is Institutionalization. When interventions appear to be effective in 

reducing respirable dust, miners and mine managers should tell others about their experience so that 

those who work in similar circumstances can benefit. Some further testing and refinements of successful 

interventions may occur. But once it is verified as an effective and feasible means of reducing an 

important source of respirable dust, the intervention will hopefully become institutionalized, i.e., become 

part of the mine’s routine operations. It may be especially helpful if someone is designated to champion 

successful approaches to dust reduction. This person should seek out good approaches, provide positive 

recognition to those who identify them, and ensure that the ideas get disseminated throughout the 

company. The period of the field tests for this study—four weeks—was too short to be able to assess the 

extent to which changes would become institutionalized at the companies that tried using the PDMs. As 

PDMs come into more widespread use, it may be possible to perform additional research focusing on the 

extent to which this new technology brings about lasting changes, and the extent to which these changes 

become adopted throughout the coal industry. 

How Much Dust is Viewed as Too Much? 

How will miners judge the acceptability of respirable dust concentrations? Hundreds of studies 

have been conducted by social scientists on the effects feedback has on human performance. Kluger and 
DeNisi (1996) provide an excellent review of this considerable body of research. They have tried to 

synthesize the findings into a theory containing several propositions about how feedback affects 

performance. Kluger and DeNisi’s theory contains several propositions about how people react to 

feedback that tells them where their performance lies relative to a goal. If a miner’s perceived standard or 

goal for acceptable dust exposure is known, it should become easier to predict how they will react to 

feedback from their PDM. 

Kluger and DeNisi’s theory suggests that, when people know they are failing to achieve their goal, 

they will usually be motivated to try to improve. They argue that people may first simply try putting more 

effort into doing the same things they are already doing to try to achieve their goal i.e., working harder. 

However, if they still find that they are failing to meet their goal, they may try to think of new and different 

strategies. They argue that if, after trying new strategies they still fail to achieve their goal, people may 

cognitively adjust their view of what constitutes an acceptable goal. People may adjust their perceived 

goal to one that is more easily achievable. For example, miners might start out disliking the idea of ever 

working in higher concentrations of respirable dust, but later on conclude that these levels are acceptable 

for short periods of time or when doing certain nonroutine tasks. Miners might try to spend less time doing 

tasks that involve exposure to high respirable dust or increase their use of respirators. But if that is not 

feasible, they might try asking others for help or ideas. Or, they might decide that it is an impossible 

situation, and give up, i.e., “learned helplessness”. 

On the other hand, if miners find that they are exceeding their goals for keeping their respirable 

dust exposure below a particular value, and it takes extra time or effort to avoid dust, Kluger and DiNisi’s 

theory suggests that some miners may relax their efforts to avoid dust. This is an interesting scenario that 

bears careful watch. If some miners’ respirable dust exposures increase following the introduction of 

PDMs, it may be necessary to remind them of the harmful effects respirable dust has on their lungs. 

Understanding how miners select goals for judging their dust exposure may help us understand 

how they will react to PDM feedback. There are at least three possible goals they might adopt. 

1) Government standards. Miners could adopt the government’s mandated upper exposure limit. 

MSHA has established 2.0 mg/m3 as the upper limit for each miner’s average exposure during an 8-hour 

shift. MSHA’s permissible exposure value for coal mine dust becomes lower with increasing 

concentrations of silica dust. In order for miners to be able to put the numbers they see on their PDM into 

proper perspective, it is important that they have a benchmark or frame of reference. As part of an 

assessment of miners’ retention of information presented to them in a training video, the miners in our 

sample were asked, “According to MSHA, what is the maximum average number of mg of coal mine dust 

per cubic meter that miners should be exposed to during an 8 hour shift, assuming no silica is present?” 

Only 20 of 30 miners could recall that MSHA’s limit for respirable coal mine dust exposure is 2 mg. This 

suggests that several of the miners may not have had a good frame of reference for evaluating the 

numbers they saw on their PDM. Additional efforts are needed to ensure that miners remember this fact 

from the training they are given. Perhaps the number 2 could be associated with the number of lungs a 

person has. Since the maximum exposure value for each section of the mine can vary depending on the 

amount of silica that may also be present in the air, the best approach to reminding miners of their upper 

exposure limit might be to print out the number and tape it on each miners’ PDM. Posters or stickers 

might also serve as effective reminders. 

2) Comparisons to co-workers’ dust exposures. Miners’ judgments about the acceptability of their 

dust exposure level might also be influenced by comparisons to co-workers who do the same job they do. 

For example, if a continuous miner operator sees that other miner operators’ exposures are consistently 

lower than his, he might begin to search for an explanation. 

3) Comparisons to past dust exposures. Miners’ judgments about the acceptability of their dust 

exposure level might also be influenced by comparing how their current dust exposure level compares to 

their prior levels (while doing the same particular task). If they observe that current levels are higher than 

past levels, they may be motivated to search for a reason. 
 

Since PDMs provide feedback on a variety of different dust concentration measures (CUM0, 

MC0, PROJ, bar chart), miners may tend to focus more on some than others. Data was collected on this 

issue by asking miners, “Of all the different types of information the PDM gives you, which type did you 

tend to look at the most?” The distribution of responses is as follows: 

Response Distribution 


dust exposure for past 30 minutes (MC0) 4 


cumulative exposure since shift began (CUM0) 8 


projected exposure for the whole shift (PROJ) 8 


bar chart 7 


One miner said he paid equal attention to MC0 and PROJ. One miner said he primarily looked at 

the numbers on the first screen rather than the bar chart; but he did not recall paying more attention to 

any one value in particular. One miner said he looked at MC0 and the bar chart an equal amount. Based 

on the responses from this relatively small sample, it appears there is no one clearly preferred indicator of 

dust exposure. As previously mentioned, almost all miners reported looking at their end-of-shift average 

respirable dust exposure before turning in their PDM at the end of the day. 

There are many unanswered questions about how miners will interpret and respond to 

information from their PDM. Will miners focus on their exposure during relatively short time intervals when 

their exposures seem to be unusually high? Will they focus on such events only when they seem to occur 

with some regularity? Will they ignore occasional or random spikes in respirable dust concentrations? 

Once PDMs have been introduced on a more widespread basis, it should become clearer which types of 

information miners attend to, and what goals miners are adopting for making judgments about the 

acceptability of various levels of exposure. 

Limitations of the conceptual model. It is important to note that the model presented above (see 

figure 3) is primarily intended to help explain the behavior of miners as they first begin using PDMs and/or 

those who work in high respirable dust on an occasional basis. It is likely that if miners have formed a 

strong habit of avoiding high respirable dust in all circumstances, they never even stop to consider any of 

the factors shown in the model. Similarly, once miners have formed a strong habit of going in high 

respirable dust to perform certain tasks, they may seldom take into consideration any of the factors 

shown in the model. They may not even take notice of the readings on their PDM. 

Over time, miners using PDMs will hopefully learn what they can and cannot do to lessen their 

exposures to respirable dust, and they may pay less attention to the PDM feedback. Only when they 

happen to notice numbers that are different than what they have come to expect will they stop to think 

about what might have caused the unusual reading. 

Miners’ Receptivity To Wearing PDMs 

Worker resistance to change is common. It was anticipated that at least some miners would have 

reservations about wearing the new PDM. In order to understand what miners might find objectionable 

about wearing PDMs, they were asked to describe any problems they might have had. They were also 

asked if they could think of any reasons why miners would NOT want to wear a PDM. The following 

issues were cited most frequently by miners: 

 Size and weight 

Light cord / sample hose 

 Cap lamp 

Attachment to miner’s belt 

Size and weight. Several miners noted that the PDM felt heavier and seemed bulkier than the 

cap lamp battery they normally wore on their belt. The PDM weighs 6.6 pounds. It is 8 ounces heavier 

than lead-acid battery cap lamp systems, but 1.5 pounds lighter than the combined weight of wearing a 

lead-acid battery cap lamp and dust sampler. As a result of recent improvements in cap lamp battery 

technologies, the lead-acid battery cap lamp systems are gradually being replaced by cap lamp systems 
 

that do not weigh as much. Some mobile equipment operators said that, due to the PDM’s size and the 

limited space in their operator’s compartment, it was difficult to sit down with it attached to their belt. 

Some noted that their PDM got “banged around” when they had to work in close quarters. 

Light cord / sample hose. The length of the cord running from the PDM on the miner’s belt to 

the sample inlet on their cap lamp was designed to be able to accommodate relatively tall people for the 

purposes of field testing the manufacturer’s prototype units. Some miners complained that the cord was 

too long and got caught on things as they worked. The cord is wrapped in a durable but rather rough 

material that some miners complained was uncomfortable when it rubbed against their neck. Those who 

maintained the PDMs noted that it would have been easier to clean mud off the cord if it had a smoother 

surface. Some miners thought that the sampling hose sometimes got pinched off when they sat down. 

When the flow of air gets cut off, an error message appears on the display screen. These error messages 

(flow error) sometimes caused miners to doubt whether their PDM was working properly. 

Cap lamps. A few miners complained that there were dark areas in the center of their spot, 

making it more difficult to see in their relatively dark work environment. Unlike the cap lamps these miners 

normally used, the light on the PDM cannot be focused with a knob. Its focus can only be changed by 

adding and removing shims from the base of the light bulb. This procedure is rather time consuming. It 

requires removing 3 screws, taking the cover off the light, changing the number of shims, and reinstalling 

the cover. If the spot is still not focused to the miner’s liking, this procedure must be repeated until the 

right number of shims is determined. A few of the PDM maintainers noted that the bulbs burned out and 

had to be replaced rather often. They also noted that the lights would sometimes go out before the shift 

was over. The batteries should be capable of providing at least 12 hours of light when fully charged. The 

manufacturer believes that the reason the lights sometimes failed before the end of the shift was because 

of poor connections between the PDM and recharging unit. The manufacturer plans to redesign this 

connection to ensure the batteries always get fully charged before miners begin their shift. Miners also 

noted that, unlike their old cap lamps, the PDM lights do not provide any advance warning before the light 

actually goes out. 

Attachment to belt. Miners at the first mine were using a significantly smaller lithium battery for 

their cap lamps. This battery fit into a small pouch permanently attached to their belts. This prevented the 

miners from attaching the larger pouches that NIOSH had provided to hold the PDM onto their belt. The 

miners at this mine were especially bothered by the larger size and the weight of the PDM compared to 

the small lithium battery they had been used to wearing. Miners at this mine used a metal clamp to attach 

the PDM to their belt. A few miners noted that PDMs held on by clamps (as opposed to the pouches) had 

a tendency to fall off their belt. To minimize inconveniences and discomfort, it is suggested that miners 

who wear PDMs should be given belts that allow attachment via either pouches or clamps, and that the 

belts have suspenders to help support the load more comfortably. 

Seven members of the mine safety staff who helped maintain the PDMs were asked to identify 

problems and offer suggestions for improving the PDMs. Many of their observations paralleled those of 

the miners who wore the PDMs. However, two additional observations are worth noting. Maintainers 

suggested changing the software such that when programming a PDM for the next sample, the default 

values should reflect whatever value was entered the previous time that PDM was programmed. They 

said that this would save time and reduce the chances of entering erroneus values during the daily 

programming process. At one mine, the safety staff strongly suggested adding some type of noticeable 

signal to let miners know when they are in an area of relatively high respirable dust, and/or when they are 

approaching the maximum exposure limit for a shift. For example, a flashing light might be used to get the 

miner’s attention. They were concerned that miners will become complacent after wearing their PDM for a 

while, and stop paying attention to the information on the display. 

Miners were asked if they had had experience wearing other types of dust monitors besides the 

PDM. All but one said yes. Interviewers said to those who had experience wearing both the old and new 

type of monitor, “I’d like you to think about how the old dust sampling system compares to the new. Which 

do you prefer?” 
 

The distribution of responses is as follows: 

Response Distribution 

18 (62%) prefer new PDM 

 7 (24%) prefer existing monitors 

 4 (14%) had no preference 

Seven miners said that 4 weeks is too long to wear the PDM. Some said they would have 

preferred the PDM or would have been willing to wear it longer if design improvements are made. 

Miners were asked to explain the reasons for their preference. Those who said they prefer the 

PDM cited the following perceived advantages: 

Provides quicker feedback 

Doesn’t fall off your coveralls like cassettes 

Combination light/sampler is more compact 

Doesn’t get in the way as much 

Provides a truer sample of actual exposure because (1) the PDM cannot be removed and left in 

fresh air while miners go elsewhere and (2) the location of the sample inlet (brim of hard hat) is 

closer to one’s nose, i.e., breathing zone. 

Those who said they prefer using traditional dust monitors cited the following reasons: 

Lighter and less bulky 

The cord does not irritate one’s neck 

Do not get in the way as much 

Could not focus the PDM’s cap light 

All of these concerns have been conveyed to the manufacturer. Hopefully, the PDM can be 

redesigned to further enhance acceptance by those who will be using it. 

CONCLUSIONS 

The information presented in this paper helps delineate the important role of PDMs as a tool for 

reducing coal miners’ exposure to respirable dust. A major strength of this paper is that it is based on 

information obtained from people who regularly work underground and who will actually be using this new 

technology. Their assessment of the potential for using PDMs to protect their lungs should most definitely 

be considered a valuable source of information. 

Results from the interviews with miners tend to support the propositions in the first three stages of 

the conceptual model. Most miners paid attention to PDM feedback and made efforts to reduce their dust 

exposure. The PDMs were not used long enough at these four mines to provide evidence about the final 

stage in the model - Institutionalization. The empirical evidence concerning the validity of the model is 

rather limited. It is hoped that the findings from this study will serve to stimulate additional research and 

will raise more questions concerning the role of feedback as a determinant of self-protective worker 

behavior. 

One should not conclude that the results of this study are representative of the entire industry. 

The sample of mines that participated in the study was small, and it was not randomly selected. It is 

possible that the sample of companies that participated in this study is more committed to ensuring their 

employees' health and safety than the remainder of the industry. 

Disclaimer: The findings and conclusions in this report are those of the authors and do not 

necessarily represent the views of the National Institute for Occupational Safety and Health. 
REFERENCES
 

Antao VC, Petsonk EL, Attfield MD (2006). Advanced cases of coal workers' pneumoconiosis: Two 

counties, Virginia, 2006. Morbidity and Mortality Weekly Report, August 25, 2006, 55(33):909­

913. 

Antao VC, Petsonk EL, Sokolow LZ, Wolfe AL, Penheiro GA, Hale JM, Attfield MD (2005). Rapidly 

progressive coal workers' pneumoconiosis in the United States: Geographic clustering and other 

factors. Occupational and Environmental Medicine, v. 62, pp. 670- 674. 

Bandura A (1977). Self-Efficacy: Toward a Unifying Theory of Behavioral Change. Psychological Review, 

84, pp. 191-215. 

Bandura A (2004). Health Promotion by Social Cognitive Means. Health Education & Behavior, v. 31(2), 

pp. 143-164. 

Hochbaum, GM (1958). Public Participation in Medical Screening Programs: A Sociopsychological Study. 

PHS publication No. 572. Washington, D.C.: Government Printing Office. 

Janz NK, Becker MH (1984). The Health Belief Model: A Decade Later. Health Education Quarterly, 

11(1), pp. 1-47. 

Janz, NK, Champion VL, Strecher VJ ( 2002). “The Health Belief Model.” In K. Glanz, BK Rimer and FM 

Lewis (ed.), Health Behavior and Health Education: Theory, Research and Practice. San 

Francisco: Jossey-Bass, pp. 45-66. 

Kluger AN, and DeNisi A (1996). The Effects of Feedback Interventions on Performance - A Historical 

Review, a Meta-analysis, and a Preliminary Feedback Intervention Theory. Psychological 

Bulletin, 1996, v. 119, No. 2 (Mar), pp. 254-284. 

Mikulincer M (1994). Human Learned Helplessness: A Coping Perspective. New York: Plenum Press. 

Peters, R., C. Vaught, E. Hall, and J. Volkwein [in press]. Miners’ Views About Personal Dust Monitors. 

Information Circular Report, NIOSH, Pittsburgh, PA. 

Pon MRL, Roper RA, Petsonk EL, Wang ML, Castellan RM, Attfield MD, Wagner GR (2003). 

Pneumoconiosis prevalence among working coal miners examined in federal chest radiograph 

surveillance programs—United States, 1996-2002. Morbidity and Mortality Weekly Report, April 

18, 2003, v. 52, pp. 336-340. 

Scott, D.F., R.L. Grayson, and E.A. Metz (2004). Disease and Illness in U.S. Mining, 1983-2001. Journal 

of Occupational and Environmental Medicine, vol. 46, no. 12, pp. 1272-1277. 

Taylor S (1983). Adjustment to Threatening Events: A Theory of Cognitive Adaptation. American 

Psychologist, Nov., pp. 1161-1173. 

U.S. Department of Health and Human Services (2005). Work-Related Lung Disease Surveillance Report, 

December 2005 Updates. Public Health Service, Centers for Disease Control and Prevention, 

DHHS (NIOSH) 

http://www2a.cdc.gov/drds/WorldReportData/UpdateDetails.asp?UpdateDateID=2 

U.S. Department of Labor (1982-2006). MSHA inspector and mine operator samples. For more 

information: Information Resource Center, Mine Safety and Health Administration, P.O. Box 

25367, Denver, CO 80225, phone (303) 231-5475; and 

www.msha.gov/techsupp/pshtcweb/dust.htm 

U.S. Department of Labor [2007]. Office of Workers’ Compensation Programs, Annual Report to 

Congress FY 2004. 

Volkwein JC, Vinson RP, Page SJ, McWilliams LJ, Joy GJ, Mischler SE, Tuchman DP (2006). Laboratory 

and field performance of a continuously measuring personal respirable dust monitor. Pittsburgh, 

PA: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease 

Control and Prevention, National Institute for Occupational Safety and Health, DHHS (NIOSH) 

Publication No. 2006-145, RI 9669. 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

APPENDIX A. INTERVIEW GUIDE FOR MINERS REGARDING PDMs 

 Form Approved

 OMB NO. 0920-0698 

 Exp. Date 11/30/2007 

DATE:_________________________________________ 

INTERVIEWER:_________________________________ 

PDM #:________________________________________ 

PLEASE DO NOT CIRCULATE OR USE WITHOUT THE PERMISSION OF THE NATIONAL INSTITUTE 

FOR OCCUPATIONAL SAFETY & HEALTH, PITTSBURGH RESEARCH LAB (412)386-6895 

1. INTRODUCTION 

Hello, my name is ________________. I work for NIOSH. NIOSH is doing a research study to get 

information on what coal miners think about the Personal Dust Monitor and how it might be used to 

reduce their exposure to respirable dust. Since you have experience using the PDM, we would like to 

interview you. The interview takes about 20-30 minutes. Your participation is completely voluntary. You 

don't need to answer any questions you don't want to. Your responses to interview questions will be 

treated in a confidential manner. We do not record the names of the people we interview. The information 

you provide will be combined with the information provided by miners at other mines. The results will be 

compiled and reported in such a way that it will be impossible to identify any single person’s answers. 

Only NIOSH staff who are involved in collecting the information will have access to your answers. 

If you do not object to being interviewed, I need you to review and sign this consent form. 

[Give form to miner for signature]. 

Do you have any questions before I begin the interview? 

2. MINER’S BACKGROUND 

To begin, I need to get some information about you and your experience in mining. 

2.1 How many years have you worked as a coal miner? 

� < 2 

� 2 - 5 

� 6 - 10 

� 11 - 20 

� > 20 

2.2 What is your present job? 

� Shuttle car � Longwall shearer 

� Continuous miner � Longwall jack setter 

� Roof bolter � Utility 

� Electrician � Stage loader 

� Mechanic � Other_____________________________ 

� Foreman 

2.3 How many years have you been on that job?__________________________ 

� < 1 year 

� 1- 3 


� > 3 


2.4 How old are you? 

� < 30 

� 30 - 39 

� 40 - 49 

� 50 and over 

3. COMPREHENSION AND USE OF PDM INFORMATION 

The next few questions are about the personal dust monitors and the information they provide. 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3.1 Including today, about how many shifts have you worn the PDM? 

� More than 15 (3+ weeks) 

� 11 – 15 (2-3 weeks) 

� 6 – 10 (1-2 week) 

� 1 – 5 (a week or less) 

3.2 During a typical shift, how many times do you look at the numbers on your PDM? 

� ZERO 


� > 0 (write number) ______________ � SKIP to 3.4 


3.3 (If looked ZERO times), Did you ever look at it? 

� No � SKIP to *** Section 5. “Problems with the PDM” 

� Yes 

3.4 Were there certain times that you were more likely to look at it than others? 

� No � SKIP to *** 3.6 

� Yes 

3.5 (If YES) When did you tend to look at it?________________________________ 

[PROBES] During breaks, certain times of the day, or phases of your job or mining cycle 

3.6 I’d like you to answer the next question using one of the options on the response card. Which option 

best describes how often you looked at your dust exposure number before you turned in your PDM at the 

end of the day? 

RESPONSE CARD A 

� 1 every day 

� 2 most days 

� 3 a few days 

� 4 never 

3.7 Your PDM has a few different screens with information about dust concentrations. The initial screen 

has values for MC0, CUM0 and PROJ. Using the options on this card, please tell me how often you look 

at this initial screen? 

RESPONSE CARD B 

� 1 more than 3 times per day 

� 2 at least once per day 

� 3 a few times per week 

� 4 less than once per week 

3.8 Another screen on your PDM shows a bar chart. Each bar represents the average dust concentration 

for 30 minutes. Using the options on this card, please tell me how often you looked at the bar chart 

screen? 

RESPONSE CARD B 

� 1 more than 3 times per day 

� 2 at least once per day 

� 3 a few times per week 

� 4 less than once per week 

3.9 Of all the different types of information the PDM gives you, which type did you tend to look at the 

most? 

� dust exposure for past 30 minutes (MC0) 

� cumulative exposure since shift began (CUM0) 

� projected exposure for the whole shift (PROJ) 

� bar chart (on screen 2) 

� Other________________________________ 

3.10 The PDM allows you to start taking a new “second sample” at any point during your shift. Did you 

ever try out the “second sample” feature on your PDM? 

� No 

� Yes � SKIP to 3.13 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

� 


3.11 (If NO) Are there any reasons why you did not try out this feature? 

[PROBES] 

Didn’t realize it was possible to start a new sample � SKIP to *** 3.16 

Didn’t remember how to start a new sample � SKIP to *** 3.16 

Didn’t want to interfere with the sample data being collected for the whole shift 

Too busy with my work to think about it 

Not worried about my dust exposure 

3.12 Do you remember which button or buttons you push to start a second sample? Please explain. 

� CORRECT 

� DON’T REMEMBER or INCORRECT 

SKIP to *** 3.16 

3.13 (If YES) How many times did you use this feature?_____________________ 

3.14 I’d like you to recall the most recent time you used this feature. What were you trying to find out? 

3.15 Were you able to find out what you wanted to know? 

� No 

� Yes 

3.16 Dust concentration numbers may go up and down throughout the course of a shift. Did you notice 

whether your numbers tended to fluctuate throughout the day? 

� No � SKIP to *** 3.18 

� Yes 

3.17 (If YES) Was it usually clear to you what was making the numbers go up and down? 

� No Please explain why_____________________________________________ 

� Yes Please explain why_____________________________________________ 

3.18 Were you ever surprised or concerned by what the numbers on the PDM display were telling you? 

� No � SKIP to *** 3.21 

� Yes 

3.19 (If YES), I’d like you to recall the most recent time this happened. What were you doing when you 

noticed the unusual reading? 

3.20 Did you do anything to try to reduce your dust exposure? 

� No 

� Yes Please describe_________________________________ 

3.21 According to MSHA, what is the maximum average number of mg of coal dust per cubic meter that 

miners should be exposed to during an 8 hour shift? 	(Assuming no silica is present) 

_______________mg 

4. ATTEMPTS TO REDUCE DUST EXPOSURE 

The next few questions are about any attempts you may have made to reduce your dust exposure since 

you began using the PDM. 

4.1 Since you began using the PDM, have you tried to make any changes to see if you could reduce your 

dust exposure? 

� No � SKIP to *** 4.13 on page 11 

� Yes 

4.2 (If YES) Please describe the types of changes you made. 

Change 1:_____________________________________________________________________ 

Change 2:_____________________________________________________________________ 

4.3 Did [Insert Change 1] make any difference in your dust concentration level? 

� No 	 Go to *** 4.8 (Change 2)
 

 OR if there are no other changes, SKIP to *** 4.13 


� Yes
 

4.4 (If YES--miner reports he/she was successful in reducing exposure) Did you look at the numbers on 

your PDM to see if they went down after you made this change? 

� No � SKIP to 4.6 

� Yes 

Don’t know
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

4.5 (If YES) What did you see? 

4.6 I’d like you to answer the next question using one of the options on the response card. Which option 

best describes how much you think this change will reduce your overall exposure to dust? 

RESPONSE CARD C 

� none 

� a small reduction 

� a moderate reduction 

� a large reduction 

4.7 Have there been any drawbacks or disadvantages to [insert Change 1]? 

CHANGE 2________________________________________________ 

4.8 Did [Insert Change 2] make any difference in your dust concentration level? 

� No SKIP to *** 4.13 

� Don’t know SKIP to *** 4.13 


� Yes
 

4.9 (If YES--miner reports he/she was successful in reducing exposure) Did you look at the numbers on 

your PDM to see if they went down after you made this change? 

� No � SKIP to 4.11 

� Yes 

4.10 (If YES) What did you see? 

4.11 I’d like you to answer the next question using one of the options on the response card. Which option 

best describes how much you think this change will reduce your overall exposure to dust? 

RESPONSE CARD C 

� none 

� a small reduction 

� a moderate reduction 

� a large reduction 

4.12 Have there been any drawbacks or disadvantages to [insert Change 2]? 

4.13 Since the PDMs were introduced, has anyone (else) at this mine changed the way they are doing 

their job in order to reduce their exposure to dust? 

� No or Don’t Know � SKIP to 4.15 

� Yes 

4.14 (If Yes) Please describe._______________________________________________ 

4.15 Can you think of any (other) ways the PDM information might be useful for reducing miners’ 

exposure to dust? 

� No � SKIP to *** Section 5 

� Yes 

4.16 (If Yes) Please describe._______________________________________________ 

5. PROBLEMS WITH THE PDM 

The next few questions are about any problems you may have had using the PDM. 

5.1 Did you have any problems using the new PDM? 

� No � SKIP to 5.3 

� Yes 

5.2 (If YES) Please describe._______________________________________________ 

5.3 Could anything be changed to improve the PDM? 

� No � SKIP to 5.5 

� Yes 

5.4 (If YES) Please describe._______________________________________________ 

5.5 Can you think of any reasons why miners would NOT want to wear the new PDM? 

� No � SKIP to 5.7 

� Yes 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

5.6 (If YES) Please describe._______________________________________________ 

5.7 Did you ever wear one of the old types of dust sampling monitors? 

� No � SKIP to *** Section 6 

� Yes 

5.8 (If YES) I’d like you to think about how the old dust sampling system compares to the new. Which do 

you prefer? 

� No preference � SKIP to *** Section 6 

� OLD Please explain why ______________________________________________ 

� NEW Please explain why ______________________________________________ 

[PROBES] Less hindrance/more comfortable to wear, Quicker feedback, More accurate 

6. TRAINING 

The next few questions are about the training you received on your PDM. 

6.1 Thinking about the training you were given before you started using the PDM, is there anything that 

could be changed to improve it? 

� No 

� Yes 

6.2 (If YES) Please describe._______________________________________________ 

6.3 Using this card, please tell me how confident you are that you know how to do each of the following 

with your PDM: 

RESPONSE CARD D 

1 very confident 

2 confident 

3 not completely sure 

4 no idea 

How confident are you that you could... 


____ 6.3.1 Find your average dust concentration for the past 30 minutes. 


____ 6.3.2 Find your average dust concentration since the beginning of the shift. 


____ 6.3.3 Find your average dust concentration for the whole shift after the unit has 


automatically shut itself off at the end of the day 

____ 6.3.4 Start collecting a second sample of dust concentration values at any time you want to 

 during a shift 

____ 6.3.5 Find out if you have already exceeded the legal limit for dust exposure during a single 

 shift 

6.4 If the MC0 number goes above 2.0, does that mean you have exceeded the dust standard? 

� YES 

� NO 

6.5 If the PROJ number goes above 2.0, does that mean you have exceeded the dust standard? 

� YES 

� NO 

6.6 How often did you refer to the Memory Jogger Card? 

Was it helpful? 

That is all the questions I have. Is there anything you would like to ask or tell me? 

Thank you for helping us with this study.