USING COAL MINERS’ EXPERIENCE TO IDENTIFY 

EFFECTIVE OPERATING CUES 

Kim M. Cornelius 

Lisa J. Steiner 

Fred C. Turin 

NIOSH, Pittsburgh Research Laboratory 

Pittsburgh, Pennsylvania 

Like many experienced workers, remote control continuous miner operators perform their 

everyday jobs making choices and decisions that they may not consciously think about. 

While performing tasks, they are continuously processing feedback and cues which guide 

them for the next move. Initial training teaches the operators the tasks necessary to operate 

the equipment and perform the job. However, with experience they are better able to deal 

with hazardous conditions and non routine situations. To better understand what potential 

cues and feedback help to guide the operators, a questionnaire was developed to learn what 

factors affect decisions. Operator responses address issues related to specific tasks, 

equipment operation, visibility, lighting, and communication issues. The information 

collected is useful to understand what cues experienced operators use to make task 

performance decisions. Results will be used to develop interventions and training for safe 

and effective operator performance. 

INTRODUCTION 

Continuous mining is a method used for 

extracting coal in an underground mine. It has 

evolved from the worker riding on the machine to 

using a remote control unit and standing away from 

the machine. When miners operated from onboard 

the machine, they developed experience in knowing 

what feedback and cues were necessary to complete 

their tasks effectively. The industry switched over 

to remote control mining with minimal changes 

made to the machine. Some advantages were 

gained by removing the operator from the machine, 

yet there were disadvantages. While riding onboard 

the machine, visibility was limited by the confines 

of the compartment and the canopy overhead. 

However, this compartment protected them from 

roof and rib falls. By using the remote control unit, 

the operator can move to a position to see what is 

necessary to operate. Yet, this exposes operators to 

risk factors such as moving equipment and falling 

pieces of rock and coal. 

The most dangerous area in underground 

coal mines is the working face where coal is 

extracted. Some of the conditions which make 

this a hazardous location are roof falls, large 

moving machinery, decreased visibility due to low 

lighting and high dust levels, and noise of the 

machines making communication between crew 

members difficult. In addition to cutting the coal, 

operators must focus attention on where they are 

positioned, the location of other crew members, 

and the proximity of the machine to the crew. 

Unsafe areas exist into which the remote control 

continuous miner operators must not move. Some 

areas are clearly defined such as beyond the 

supported top, which is defined by the last row of 

bolts supporting the roof. But this is not always 

readily visible, especially in lower seam mines. 

Other areas are not clearly defined to the operator. 

Research is being conducted to identify safe and 

unsafe zones for the operator. Since the mining 

environment is dynamic, it does not lend itself to 

implementing physical barriers to keep operators 
out of the unsafe zones; the operators must 

constantly process their position in relation to those 

unsafe zones. Remote control operation has 

required the continuous miner operators to divide 

their attention and process more information 

simultaneously. Defining and prioritizing what cues 

and feedback are most useful and how operators 

focus their attention leads to better operating 

decisions. This information can then be used to 

develop safe, realistic operating procedures 

allowing operators to focus on the most important 

feedback. 

When analyzing human-machine systems, it 

is important to examine the components of the 

human and the machine within the work 

environment. The mining environment is a unique 

challenge. The work environment of a mine is very 

difficult to mold in comparison to a factory setting 

where the worker may gather designed and 

controlled information from machine displays. In 

the mining setting, the equipment designer can 

control how the machine functions, but not the 

surrounding environment. The environmental 

hazards in the mine cannot be removed by 

redesigning the system. This dynamic environment 

presents many hazards and information that must be 

continually monitored by the continuous miner 

operator. 

THESIS 

The ability to process and utilize feedback 

information is an important component of the 

human-machine system. Safe and effective control 

of the system is dependent upon the worker properly 

sensing pertinent information and processing it to 

make the right decisions to control the system. 

Depending on the feedback or cues provided by the 

system or environment, the worker makes necessary 

modifications. Experienced miners have expanded 

their knowledge, skills, and abilities to perform 

safely and effectively. By identifying the specific 

feedback and cues used to perform their job, 

interventions and training methods can be designed 

to improve safety for all operators. 

SOURCES OF INFORMATION 

There were a number of data inputs from 

earlier phases of this work which helped form the 

instrument used to collect information from 

miners to identify feedback and cues they use to 

perform their job. A preliminary task analysis 

questionnaire was developed when this project 

was initiated to identify general safety issues. In 

particular, the goal was to determine what aspects 

of this technology were problematic to the mining 

industry (Steiner et al., 1994). Overall, workers 

had a positive attitude toward this technology. 

However, visibility for continuous miner operators 

and some aspects of maintenance were identified 

as common problems. Data obtained from this 

interview guide were used to identify what areas 

needed further examination and to devise a 

systematic approach to analyze this technology. 

Subsequently, a work sampling technique 

was adapted to collect information on the needs of 

the workers doing specific tasks in the mining 

cycle (Steiner et al., 1997). The goal was to learn 

what portion of time was spent by the operator on 

various tasks and where the operator was 

positioned in relation to the machines and other 

crew members during those tasks. At 

predetermined intervals, data were collected on 

where the operator was in the cycle, what task was 

being completed, where the machines and crew 

members were positioned, and in what direction 

the operator was looking. Operator position and 

direction of view data were needed to take an 

initial look at what visual feedback and cues were 

being used. Resulting observations revealed that 

the worker would sometimes stand in an unsafe 

area in order to see the cutting head of the 

machine during longer cuts. Also, turning a 

crosscut appeared to be the most variable and 

difficult task for the operator. 

To more narrowly focus on some of the 

problem areas, another questionnaire was 

developed. The physical location of the operator 

during the turning task was an evident concern. 

During the work sampling, observational data 

were collected. However, due to the constraints of 

the environment, it was difficult to gather 

information from the operator which would 
explain exactly what the operator was looking at 

and why it was necessary to see that particular cue. 

Also, it was determined that operators were having 

difficulty seeing the mining machine throughout the 

cutting cycle. Thus, there was a need to identify 

what other types of feedback, such as audible and 

tactile, that were possibly used to compensate for 

the decreased visibility. 

The questionnaire was developed to obtain 

answers which would provide insight into what 

specific types of feedback and cues an operator uses 

to safely and effectively perform the job. Also, the 

questions were designed to gain insight into what 

special skills, knowledge, and abilities were 

necessary to operate the continuous mining 

machine. Questions were mainly open-ended and 

focused on learning the specific actions and thought 

processes used to complete the tasks associated with 

the job. Using this questionnaire, a total of 32 

continuous miner operators were interviewed at 

three different mines. The questionnaire was 

interactively administered at the worksite in a 

structured interview format. 

While conducting the earlier activity 

sampling study, it was determined that cutting coal 

while turning a crosscut was the most challenging 

part of the cutting cycle. This is due to the 

difficulty associated with maneuvering the machine 

and positioning of the worker in a confined space. 

Questions concerning crosscut turning aimed to gain 

a better understanding of operator positioning 

during this task. Operators were asked questions to 

determine why they stand in a particular location, 

when and why they need to move from this position, 

and which cuts are most difficult to take and why. 

Other questions aimed to identify the information 

and feedback the operator used while operating the 

continuous mining machine. For example, the 

respondents were asked: 

b What is the most important feedback while 

mining a cut? 

b During the last twenty feet of the cut, what 

in particular do you look at to stay on sight 

line? 

b Do you have a problem with visibility when 

cutting? 

b Have you had any problems with the 

lighting on your machine? 

Two questions were asked to gain insight 

into what skills were needed to operate the 

continuous mining machine: 

b If you were to teach me to operate a 

continuous mining machine, what would 

be the most important points you would 

tell me about taking a cut? 

b What do you think makes one operator 

better than another? 

FINDINGS 

The responses formed a starting point from 

which to examine information input and 

processing of remote control continuous mining 

operators. Specific cues which primarily 

consisted of visual, audible, and tactile feedback 

used to complete the tasks were examined. 

Additional information was summarized and used 

to examine the skills and abilities needed to 

effectively operate the mining machine. 

Responses concerning operating cues 

provide key information to understanding the 

many variables which the worker must process 

and balance while operating the mining machine. 

These factors play a major role to determine the 

best position for the remote control continuous 

miner operator. Often, equipment and mining 

plan layouts factor into this determination. For 

example, the continuous mining machine has thick 

cables running back from the machine which must 

be handled and repositioned continually 

throughout the cutting cycle. Another important 

factor of positioning related to the mining plan is 

determining the location which maximizes 

availability of fresh air and minimizes exposure to 

dust. The mining plan also determines operator 

positioning as it relates to the risk of being hit by 

falling roof and rib. In addition to all of these 

factors, the operator needs to be positioned where 

visibility is best. 

Specific feedback supplied by the workers 

was categorized into three types of operating cues: 

visual, audible, and tactile. Their responses 

suggest that visual cues provided the most useful 

information. The operators must continually 

monitor the above mentioned items concerning 

their current location and when to move to a 
different position. Visual cues were necessary to 

keep the machine on line and to know when to 

terminate a cut, either in reaction to a geological 

problem or in compliance with the mine plans. 

Specifically they observe the color of the dust, 

sparks from the drill bits, and the angle of the 

cutting head. Workers used visual input to watch 

for haulage vehicles traveling to and from the 

working area and to monitor the level of methane 

present at the working section. At times 

communication between the crew was visual. For 

example, workers use their cap lamps as a means of 

communication. 

Operators report that they listen for 

particular information too. For instance, they could 

identify a sound made when the cutting head hits 

rock which would indicate that they were cutting 

too high into the roof; a different sound determined 

when the cutting head hits the roof and the roof is 

about to fall. Another form of audible feedback was 

verbal communications. Information about hazards 

is provided by other workers on the section as well 

as workers from the previous shift. 

Vibratory feedback was a common source 

used when operators rode on the machine. It was 

surprising to learn that the remote control operators 

still use this feedback. They can feel the vibrations 

of the machine by resting the remote control unit on 

top of the machine or leaning against the machine. 

However, this feedback is not encouraged since it 

can increase the operators’ risk of being hit by 

falling roof. 

Operators were asked to describe the most 

important points they would make if they were to 

teach the interviewer how to operate the machine. 

Responses consisted of some ‘textbook’ type 

information which reiterated what is learned in 

initial training such as protecting themselves from 

the roof and rib falls and watching for the moving 

equipment. Other responses revealed the ‘tricks’ 

that a miner might gain with experience such as, 

using particular reference points on the mining 

machine to measure distances for cutting and 

watching the direction of a haulage vehicle’s wheels 

to know which way it is about to turn. 

Continuous miner operators were also asked 

to describe what makes one operator better than 

another. Many of the responses in this category, 

unfortunately, turned out to be characteristics 

which would be difficult to measure, such as, 

desire to do a good job, leadership ability, good 

concentration, ability to pick up things quickly, 

and patience. 

DISCUSSION 

Data collected from these remote control 

continuous miner operators helped to identify 

what information is important at various points in 

the mining cycle. An operator focuses attention at 

a given moment on the priority element, but then 

must quickly divert attention to something else. 

For example, when shuttle cars pull up to receive 

the next load of coal, the continuous miner 

operator must divert some attention to the moving 

vehicle and then must watch one direction to 

guide the machine cutting and loading the coal 

while also watching the opposite direction to 

know when the car is full. 

At times, operators appear to be 

overloaded by the amount of visual information 

they need to monitor. Additionally, visibility can 

be poor due to the low lighting and concentrated 

dust in the air. The US Bureau of Mines 

previously conducted work to identify the most 

important visual attention locations for the 

continuous miner operator riding on board the 

machine (Sanders, 1981). This was one of the 

main concerns since visibility was limited by the 

canopy and compartment. The ability to see these 

visual cues has improved since the operator now 

can move around and get into a position to see 

what he needs to see. However, the lighting 

scheme on the mining machine is inadequate and 

there are additional visual cues that require 

attention because the operator has lost the 

protection of the compartment and canopy 

overhead, and must pay attention to potential 

hazards such as moving equipment and falling 

roof and rib. 

Operator positioning plays an important 

role in receiving visual cues. This is not only due 

to operators moving to obtain a better line of sight, 

but since operators can be overloaded by visual 

cues and unable to divide attention to all the 

necessary places at given times in the cycle, it is 
common for operators to move to the other side of 

the machine to protect themselves from other 

moving equipment and falling pieces of roof. 

Inexperienced remote control continuous 

miner operators focus more attention on how to 

operate the machine itself and have less attention to 

divert to watching the numerous cues that must be 

followed to ensure safety of the workers in the 

section. For example, one of the most difficult 

tasks for remote control continuous miner operators 

is to make a turn in the coal seam. For less 

experienced operators, performing this task may 

require full attention to be paid to the machine 

itself. Whereas, more experienced operators have 

found ways to make tasks somewhat easier and it 

affords them the attention necessary to focus on 

where they are positioned in relation to the moving 

equipment, the supported roof, and where other 

workers are positioned. Some problems can be 

solved through equipment redesigns for improved 

lighting schemes or technology enhancements for 

methane and dust control. However, other solutions 

which help to minimize or eliminate the need for 

operators to divide their attention to multiple 

resources in this complex environment, may be 

more challenging to resolve. 

New operators receive on-the-job training. 

For the most part, there is no formal training 

program for operating the machine in this complex 

environment. Their initial ability is limited to the 

effectiveness of the operator doing the training. 

This study is an initial attempt to identify 

important cues used by expert continuous miner 

operators. It is hoped that a better understanding 

of these cues will lead to modifications in work 

methods, equipment, and training that improve 

miners’ safety. 

REFERENCES 

Sanders, M.S. (198 1). Determining what needs to 

be seen and what can be seen from underground 

mining equipment. In Ergonomics-Human 

Factors in Mining (pp. 56-69). Information 

Circular IC 8866. U.S. Department of Interior, 

Bureau of Mines. 

Steiner, L.J., Turin, F.C., and Hamrick, C.A. 

(1994). Ergonomic and Statistical Assessment of 

Safety in Deep-Cut Mining. In Improving Safety 

at Small Underground Mines (pp. 124- 132). 

Special Publication 18-94. U.S. Department of ’ 

Interior, Bureau of Mines. 

Steiner, L., Turin, F., and Cornelius, K. (1997). 

A Method for Evaluating System Interactions in a 

Dynamic Work Environment. In B. Das and W. 

Karwowski (Eds.), Advances in Occupational 

Ergonomics and Safety II (pp. 603-606). 10s 

Press and Ohmsha. 

This work is not subject to U.S. copyright restrictions.