SAFETY BREAKTHROUGH--

REDUCED EXPOSURE

MINING SYSTEM (REMS)

By J. J. McClelland, R. F. Randolph,

 G. H. Schnakenberg, Jr., and R. S. Fowkes

SPECIAL PUBLICATION SP-26-94

UNITED STATES DEPARTMENT OF THE INTERIOR

BUREAU OF MINES
U.S. Department of the Interior

Mission Statement

As the Nation’s principal conservation agency, the Department of the

Interior has responsibility for most of our nationally-owned public

lands and natural resources. This includes fostering sound use of our

land and water resources; protecting our fish, wildlife, and biological

diversity; preserving the environmental and cultural values of our

national parks and historical places; and providing for the enjoyment

of life through outdoor recreation. The Department assesses our

energy and mineral resources and works to ensure that their

development is in the best interests of all our people by encouraging

stewardship and citizen participation in their care. The Department

also has a major responsibility for American Indian reservation

communities and for people who live in island territories under U.S.

administration.
 Computer engineer 1

 Research psychologist 2

 Research physicist 3

 U. S. Bureau of Mines, Pittsburgh Research Center, Pittsburgh, PA

Safety Breakthrough—

Reduced Exposure Mining System (REMS)

By

J. J. McClelland, R. F. Randolph, 1 2

G. H. Schnakenberg, Jr., and R. S. Fowkes 3 3

Contents

 Page

Executive Summary ................................... 1

Introduction ......................................... 3

Present Mining Methods ............................... 7

The Solution: Reduced Exposure Mining System (REMS)... 9

REMS Benefits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Reallocation of Human Resources and Training . . . . . . . . . . . 15

The U.S. Bureau of Mines—Developing Technology for

 Health, Safety, and Industry Support . . . . . . . . . . . . . . . . . . . 17

Impacts of Advanced Technology in Parallel Industries . . . . . 19

Spin-off Technologies for Mining and Other Industries . . . . . 21

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Acknowledgment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Addendum

 The USBM Pittsburgh Research Center . . . . . . . . . . . . . . . . . 35

 Mining Robotics Laboratory . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Reduced Exposure Mining System Page 1

Executive Summary

The face area of a continuous mining section of an underground coal mine is the most

dangerous area in the mine. Workers there are at nearly twice the risk of death or disabling

injury than those in other parts of the mine. Despite extensive training of miners and

improved equipment and mining methods, fatality and injury rates have remained constant

during the past few years. It is clear that advanced research is necessary to apply new

technologies or modify work procedures to solve the continuing problem of the loss of lives

and the numerous injuries at the mine face.

A U.S. Bureau of Mines research program is developing a Reduced-Exposure Mining

System (REMS) that relocates personnel operating the mining machinery at the face away

from the hazards to a nearby haven of relative safety. REMS uses proven technologies of

computer automation and robotics to help control the operation of the mining machines at

the face, while personnel are moved away to a nearby, safe control room. In this protected,

well-ventilated environment, they can supervise or control the operation of the machines

while viewing what the machine is doing using video and graphic display monitors.

REMS has the potential to be the single most important improvement in the safety and

health of underground coal mine workers since the introduction and enforcement of the

Federal Coal Mine Health and Safety Act of 1969.

The REMS program is one of the more significant research efforts of the U.S. Bureau of

Mines, Department of the Interior, which has been mandated by Congress to "conduct

necessary research and development to improve working conditions and practices in coal

and other mines...to prevent accidents...to develop new and improved underground and

other equipment...which will provide greater safety."

REMS clearly meets the requirements of this Congressional mandate. It has been

developed to save lives and to minimize human suffering, and is the only research program

to address the safety of the mining system at the mine face. In addition to protecting mine

workers, REMS will redefine their roles, allowing them to operate in a more productive,

environmentally-safe manner.

REMS technology is also available and is being tried and tested for applications other than

underground mining. Various aspects of its system can be adapted to improve productivity

and protect workers in industries such as civil engineering and construction, nuclear and

hazardous waste detection/cleanup.

Reduced Exposure Mining System Page 3

 Figure 1.- Typical remote control continuous mining 

 machine and its operator.

"The best way to protect an

individual is to remove that

individual from the hazard."

-Ronald Wooten

Introduction

Between 1986 and 1992, there were

268 deaths and 54,642 severe injuries

to workers in underground U. S.

mining operations. Clearly, this level

of health and safety risk is not

acceptable.

While most underground coal mining

jobs are dangerous, some are much

more dangerous than others. Many

jobs in an underground coal mine are

clustered around the working

face—the place where machinery

digs coal from the surrounding rock. The hazards in this area are numerous: When the coal

is removed, the ground around it becomes unstable and can cave in on the workers. The

mining machines used there are large, heavy,

powerful, and move in many different directions in

a very confined space, presenting danger to

workers. Also, the machines churn up coal dust

that causes black lung and other ailments. Figure

1 shows a modern radio remote controlled

continuous mining machine and its operator.

In a typical mine, the jobs with the greatest exposure to hazards involve operation of

machinery that cuts tunnel-like passages into the coal (the continuous mining machine) and

machines that insert supportive steel bolts into the rock above the work area (roof bolting

machines).

The workers who endure these hazards are at almost twice the risk of death or disabling

injury than co-workers in other safer areas of the mine. 

Of the statistics quoted above, 106 of the 268 deaths and 21,552 of the 54,642 severe

injuries occurred in jobs involving equipment at the working face. 

The operators of roof bolting and continuous mining machines account for only 21% of the

work force but suffered 40% of the deaths and 39% of the lost-time injuries during

1986-1992. These death and injury rates are almost twice the rate for workers in other

underground mining jobs (see figure 2). The estimated total cost of the 106 fatalities and

21,552 lost-time injuries was $327 million from 1986-1992. On average, each fatality cost

over $1 million and each lost-time injury costs in excess of $9,000.
Fatalities

Lost-time

Injuries

Operators of mining and

roof bolting machines

(20.9% of the workforce)

Miners in exposed jobs

50 more than expected

had 39.6% of the 268 fatalities

Miners in exposed jobs had 

39.4% of the 54,642 lost-time injuries

10,132 more than expected

Other underground 

mining jobs

(79.1% of the workforce)

Page 4 Reduced Exposure Mining System

Figure 2.- During 1986-1992, operators of mining and roof bolting machinery had almost twice the expected

number of fatalities and injuries.

Figure 3 shows that the improvement in fatality rate has bottomed out over the last few

years; the injury rate also shows a flattening trend, the recent upturn due to a more

comprehensive accident reporting procedure. Successful research programs will be the

ones that attack this problem in a new way—either by the application of new technologies

or addressing and modifying work procedures. 

When workers are exposed to hazardous conditions, the most effective remedy is simply

to reduce their exposure, if possible. In underground coal mining, the hazards revolve

around just a few activities in a small area. If workers can be relocated to a safer area

where they perform less hazardous jobs, the number of injuries and deaths will be

dramatically reduced. 

Ronald Wooten, Safety Vice President for Consolidation Coal Co., in testimony on behalf

of the National Coal Association (NCA) to Congressional Oversight Hearings in 1990 said,

"The best way to protect an individual is to remove that individual from the hazard. This

simple and fundamental underpinning is, we believe, at the heart of the [Bureau of Mines']

Automated Mining Systems program."1
Reduced Exposure Mining System Page 5

Figure 3.- Trends in underground coal mining fatalities and lost-time rates, 1930-1990.

Until recently, the relocation of workers was impractical because the technologies needed

to make the changes were not available. The U. S. Bureau of Mines (USBM) and others

have traditionally improved safety through methods such as modifying work procedures,

developing and implementing training, and improving machine design. The return from

these traditional approaches, while effective, may be diminishing. The historical trend of

continuing improvements in fatality and injury rates in the mining industry began to taper

off in the 1980's. The next great steps in improving safety will require fundamental changes

in the mining system, including the technology, work force skills, and the tasks miners

perform. New technologies are making these changes feasible.

Reduced Exposure Mining System Page 7

Present Mining Methods 

The following is a description of the mining system of a productive room-and-pillar mine:

Two mining methods predominate in producing most of our nation's underground coal—

the room-and-pillar method and the longwall method. Both methods are entirely dependent

on the same three pieces of equipment—the continuous mining machine, roof bolting

machine, and a haulage system—but in different ways. In room-and-pillar mining, a

continuous mining machine removes the coal by cutting between three and seven parallel

tunnels (called entries). These entries are then cross-connected by right angle - or angled -

entries, the intersection of which is termed a room. The remaining coal between the entries

is called the pillar. In longwall mining, the longwall panel is "developed" by driving two

parallel 3-entry room and pillar sections separated by a few thousand feet. The time it takes

to establish a longwall section is presently constrained by the time it takes to develop these

room and pillar entries. The mining process is described below.

A continuous mining machine is operated either with the operator riding inside a

compartment on the machine or by radio remote control, with the operator standing within

proximity of the machine. A miner helper may be present to pull the mining machine

power cables and water hoses out of the way as the mining machine backs out of the newly

mined area. Two additional workers drive the shuttle cars which carry the coal from the

output of the mining machine to the conveyor belt a few hundred feet away. In a few more

advanced mines a single worker controls the front end of a continuous haulage system that

is used in place of the shuttle cars.

Coal is mined by advancing the cutting drum of the continuous mining machine into the

coal in a series of sump (forward advance of the cutting drum into the coal) and shear

(downward sweep of drum) actions, creating a tunnel (entry). A number of factors limit

how far (deep) the machine can advance before having to pull out to allow the roof to be

bolted. Presently, the haulage operator cannot go under unsupported ground, limiting the

depth to about 12 m (40 ft). In a very few mines, the use of radio remote controlled

continuous miner and continuous haulage allows mining to 30m (100 ft). This increases the

efficiency of mining by reducing the number of times the machine must be moved from one

entry to another. 

Any person who is standing near these moving machines is at risk of being pinched between

the equipment and the mine walls, as well as exposed to dust and noise. Occasionally, the

roof, even though it is supported where the worker is standing, may cave in on the

equipment and the worker.

While mining of an entry is going on, two other workers are operating a dual boom roof

bolting machine in another nearby freshly mined entry. Here, the machine is maneuvered

into the first area of unsupported roof. The roof is first supported temporarily with
Page 8 Reduced Exposure Mining System

hydraulic jacks. A worker at each boom then drills a deep hole upward into the ground

above the entry. A long bolt is placed in this hole, and tensioned to hold the roof strata

together. The jacks are released and the machine is moved further into the entry and the

process repeated. In roof bolting, the worker is susceptible to cave-in or getting pinched

or injured by the equipment. 

Shuttle car drivers are less frequently injured, yet their equipment represents a hazard to

others. More progressive mines are using, or are considering using, continuous haulage

where feasible.
FACE

CONTINUOUS MINER

ROOF BOLTER

ENTRY

CONTROL

CENTER

MAIN BELT

RIB

COAL PILLIAR

CONTINUOUS HAULAGE

CROSSCUT

Reduced Exposure Mining System Page 9

Figure 4.- Underground coal mine work site using the

Reduced Exposure Mining System (REMS).

The Solution: Reduced-Exposure

Mining System (REMS)

The technology that can virtually

eliminate worker exposure to hazards

while performing the mining

activities of room and pillar mining is

within our grasp. 

Within the last decade, technology in

the form of powerful yet relatively

inexpensive computers, sensors, and

graphic video displays, has advanced

to the point where it can be used with

mining equipment to avoid most mine

face hazards. The solution is the

relocation of machine operating

personnel away from the hazards to

a nearby haven of relative safety.

This simple statement embodies the

purpose of the USBM research

program on reduced-exposure

mining.

 

REMS exploits the technologies of automation and robotics and can also be referred to as

computer-assisted mining. REMS uses sensors and computers to control the operation of

the mining machines for the most hazardous mining tasks, eliminating the need for a worker

to ride on, stand beside, or be within line-of-sight of the machine. The machine operators

are instead located in a safe control room nearby, supervising the computer operation of the

machines (see figure 4), virtually eliminating their exposure to the hazards that cause death

and injury.

The machines involved are the continuous mining machine, a continuous haulage system

(or a pair of shuttle cars), and a roof bolting machine.

REMS has the potential to be the single most important improvement in the safety and

health of the underground coal mine worker since the introduction and enforcement of the

Federal Coal Mine Health and Safety Act of 1969. Thus, the REMS research program is

one of the most significant current research efforts of the USBM. 

With REMS, workers use a combination of computer and remote manual operation of the

mining machines. Video and computer displays are used to monitor mining operations from

the control room. 
Page 10 Reduced Exposure Mining System

REMS has the potential to be

the single most important

improvement in the safety and

health of the underground coal

mine worker since the

introduction and enforcement of

the Federal Coal Mine Health

and Safety Act of 1969.

A typical scenario is the following: After the

mining machine and haulage system are manually

moved into a starting position, the workers walk to

the control hut, take a seat, and turn over the

mining actions of the continuous mining machine

and continuous haulage system to computers. The

machine operators view the progress of their

machines on a video display terminal. Upon

encountering unusual situations, the computer will

alert the operator and request manual intervention

and control from the operator. 

Similarly, the roof bolting machine will be controlled by computer. Once it has been

manually placed into an approximate starting point, the computer will guide it to the proper

positions to place the bolts for the entire depth of the entry. As with current practice,

mining and bolting occur simultaneously, but in different entries.

When the mining machine has cut to the depth required - usually 6 to 30 m (20 to 100 ft) -

it will withdraw to its starting point. The workers will then manually move the machine to

the starting point for the next cut, usually in an adjacent parallel entry. The roof bolting

machine is moved to the entry just vacated by the mining machine. 

Machine maintenance/servicing will be done under a safe roof between mining activities

as is the current practice. Mining machine bits will be changed if needed, drill bits will be

inspected and changed, and the bolter loaded up with bolts and anchors. The workers

remain in relatively safe areas performing these routine activities. The ventilation will be

moved if necessary, but most ventilation air will be provided by an additional system that

can be mounted on the continuous haulage system. Once the machines are serviced and set

into position, the workers will retreat to the control station and turn their operations over

to the computers. 

In summary, REMS provides the technology that enables the operators of the mining

equipment to operate their machines at a distance, in safety, and as will become clear, with

enhanced efficiency. 
Reduced Exposure Mining System Page 11

REMS offers tangible benefits in

areas such as safety, health,

the environment, and

productivity.

REMS Benefits

For years, industry, government and university researchers have worked to identify ways

to reduce the health and safety risks associated with mining. Significant gains have been

realized in many areas, leaving no doubt that our mines are much safer and more productive

than the mines in which our forefathers risked their lives. Health, safety, and production

statistics support this reasoning. Unfortunately, lives are still lost from dangerous methane

ignitions, fires, and cave-ins. Also, workers continue to suffer a disproportionately high

percentage of disabling injuries, and long-term debilitating diseases such as pneumoconiosis

and silicosis. 

Traditional research focuses on identifying methods, procedures, protective equipment, and

preventive techniques that will allow mining personnel to work in relative safety, but

without removing the worker from the hazardous face area. These solutions keep the

worker and machine in a precarious situation where the unforeseeable actions of both can

lead to disastrous results.

REMS is a dramatic, yet logical, shift away from a traditional research approach. It does

not struggle to find ways to minimize the hazard itself or its effects, but instead physically

separates humans from the hazard.

REMS offers tangible benefits in safety, health,

the environment, and productivity. The benefits

of REMS will accrue to any mine where

continuous mining machines are used. This

includes longwall mines as well as single- and

multiple-section continuous mining operations.

The following is a list of the most significant

benefits offered by REMS:

Safety

Relocating the face workers to a control room will have the most dramatic benefit to the

industry by its impact on worker safety. No longer will the worker be working in fear of

cave-ins, of being crushed by the very machine they operate or one operated by a coworker, of being hit by debris from a bursting pillar, or of being caught in equipment

mechanisms—all hazards of the working face. It is in this area that the roof has not yet

been supported or, if it has, still remains unstable and unpredictable as the earth continues

to settle around this newly created void. It is here that large, heavy equipment is

maneuvered to mine coal in a very confined space, and shuttle cars jockey into position

behind the machine to receive the coal. The simple act of relocating the worker from the

face area and activities could prevent the loss of about 15 lives annually. 
Page 12 Reduced Exposure Mining System

Health

Relocating the face workers will also avoid several serious health hazards present at an

underground mining section. Exposure to respirable coal and quartz dust will be reduced

to near zero or eliminated, thus leading to a reduced occurrence of the debilitating and often

fatal diseases, pneumoconiosis and silicosis. In addition, mining machines working within

narrow working areas generate an incredible amount of noise that can lead to permanent

hearing loss. 

Additionally, there will be less need to manually and physically manage heavy power

cables and water lines. The cables will be handled by the continuous haulage system. This

will lead to a substantial reduction in back injuries, which account for a significant number

of lost-time injuries at the working face, the cost of which is excessive.

Environmental

Coal cutting by the continuous mining machine will be better controlled; deviations out of

the coal seam and into roof or floor rock will be greatly reduced resulting in cleaner coal

and a minimum of unrecovered resource. Existing mining systems require visual

observations and to some extent the trained ear to determine when floor and roof rock is

being cut and coal is not. Only the most experienced mining machine operators can

minimize the likelihood of cutting rock. When rock is mixed with coal it must be separated

and discarded before the coal can be shipped. It is this waste product that is dumped in

unsightly heaps at the surface. Coal interface sensors will provide better ways to keep the

machine within the seam, resulting in cleaner coal, less waste on the surface, and lower

cleaning costs. More accurate cutting of the entries will eliminate the practice of leaving

larger than necessary pillars "just in case we cut too much on the last pass or might cut too

much on the next entry." More accurate cutting control will enhance resource utilization.

Productivity

With advanced guidance, navigation, and ventilation technology, REMS will increase

machine efficiency as deeper cuts are taken with fewer intervening place changes. Existing

Mine Safety and Health Administration (MSHA) regulations for mining machines limit the

depth of cut to a maximum of 12 m (40 ft) simply because the haulage operator would be

under unsupported roof. Deeper cutting places the machine operator at a disadvantage

because dust and equipment obscures the view making control of machine less accurate.

Ventilation of deep cuts requires special techniques to clear dust and methane and to

monitor the methane level. Today, increasing mining efficiency by deep cutting is hindered

by lack of adequate technology. Consequently, frequent place changes (the miner leaves,

the bolter arrives) are required. These place-changes take time and cost money because the

time spent moving means less time cutting coal. With the REMS, depth of cut may

exceed 30 m (100 ft), thus reducing the number of needed place-changes by 60 percent.
Reduced Exposure Mining System Page 13

The REMS is ideally suited to longwall development where rate of forward advance is of

primary importance. With a herringbone, 3-entry pattern, and a REMS, mining will be

highly efficient and almost continuous. 

Additionally, it should be pointed out that productive mines are usually large, running

several room-and-pillar or longwall sections. The introduction and use of REMS would

eventually involve its use in all of the sections of a mine, not just one. Also, REMS would

allow small mines to step up to a safer and more efficient technology without the high

capital cost of a longwall system.

Cost-Benefit

The cost of a single death to the mining industry and to society is approximately $1 million.

However, the loss of a human to his or her family and loved ones is immeasurable. The

mine face area, which is addressed by REMS, accounts for approximately 17 fatalities per

year. Most, if not all, can be eliminated by using this technology. This represents a savings

of over $17 million annually. The annual cost of the research program is less than one-third

of that. There are further benefits owing to drastically reduced injury rate and incidents of

black lung. Additionally, increased utilization of resources (both labor and capital),

increased coal recovery, better mine geometry, and less preparation costs owing to cleaner

coal, tend to lower the cost of coal and hence its price to the utilities using it. 

The effects of USBM research are permanent; once reduced-exposure mining is established,

savings will continue to be realized every year thereafter. 

In summation, REMS will significantly reduce accidents, fatalities, and injuries occurring

at working sections of underground coal mines; decrease incidence of black lung and

hearing loss; improve overall efficiency of mining equipment through an increase in

equipment utilization; and have a positive environmental impact through increased mineral

recovery. 

The payoff of this research is high and is much greater than its cost. To the companies

who adopt REMS, the payback will be realized in a short period of time.

Reduced Exposure Mining System Page 15

A company or industry that fails

to modernize cannot remain

competitive with other

companies or industries that do

adopt this technology.

-Uday Kumar

The impact of automation and

robotics on employment in

mining, construction,

transportation, communications,

and agriculture will not be

drastic.

-Ayres and Miller

Reallocation of Human Resources

and Training

As to the effect that automation will have on jobs, Frantz and King did an in-depth analysis 2

of four stages of automation in a continuous mining section in terms of safety, productivity,

and employment. They then compared their results with those of a present continuous

mining section. Their investigation showed that the automation of a continuous mining

section improved the health and safety of mine workers, increased section productivity,

decreased mining costs, and led to increased employment. The increased efficiency of the

automated systems made the mine more

productive and led to increased hiring. 

The authors present tables for the present system

and the systems in various stages of automation,

which give a detailed breakdown of underground

and surface employees by job title. 

Other tables in this report show that for the mine

using the present system, 400 employees are

required and productivity is 11.3 clean tons per person-shift. Of the four stages analyzed

by Frantz and King, the fourth closely approximates REMS; that is, production personnel

are removed from the working face with the only workers in that area being there for

emergency service and planned maintenance. Stage IV automation involves 618 employees,

and produces 21.8 tons per person-shift. Thus, the move from the present system to REMS

will increase the number of employees from 400 to 618 while increasing productivity from

11.3 to 19.6 clean tons per person-shift.

In terms of safety, the authors present detailed tables showing the frequency of accidents

due to a variety of causes (cave-ins, face or rib falls, haulage, bumps or bursts, etc.) for the

present system and for each of the four stages of automation. In brief, the overall accident

frequency per million person-hours for the present system is 42.8, while for Stage IV

automation (REMS) it is 24.0; thus reducing the

possibility of accidents by almost 1/2.

In a paper dealing with mine mechanization and

automation, Uday Kumar asserts that advanced 3

technology is needed to save jobs. According to

Kumar, a company or industry that fails to

modernize cannot remain competitive with other

companies or industries that adopt this technology.

And although mechanization and automation alter

the nature of human involvement at various levels

of operations in mines, humans are still and always will be needed to monitor, supervise,

and execute mining operations.
Page 16 Reduced Exposure Mining System

Ayres and Miller claimed that the impact of automation and robotics on employment in 4

mining, construction, transportation, communications, and agriculture will not be drastic.

These fields will continue to use human workers in essentially the same types of jobs that

they presently perform.
Reduced Exposure Mining System Page 17

The U. S. Bureau of Mines—Developing

Technology for Health, Safety,

and Industry Support

The USBM has been involved in electrical systems and instrumentation research for over

half a century. During the last 12 years, it has enhanced its research staff to include

specialists in computer software programming, and specialized mechanical systems. The

Bureau's Pittsburgh (PA) Research Center, where a Mining Robotics Development

Laboratory was recently dedicated, is the lead center for REMS research. The facility

features offices adjacent to an enclosed high bay area where mining equipment and systems

can be tested. Additionally, the Bureau's Spokane (WA) Research Center is performing

research specifically on the complex problem of the autonomous roof bolting machine, a

critical component of the REMS.

In the late 1980's, a progressive mining company sought out the USBM automation research

group at the Pittsburgh Research Center and proposed that working together would be

beneficial. They offered a test area in a mine, while utilizing the research skills of the

USBM. They came to the conclusion that they would ultimately benefit from the Bureau's

research on REMS. Under a Memorandum of Agreement (MOA) the USBM used the test

site for two years, in which great progress was made toward computer-assisted machine

guidance and control. At that point, the mine changed ownership and the machine was

returned to the Pittsburgh Research Center for technology updates and additional surface

testing.

Recently, several other mining companies and machine manufacturers have made inquiries

to the USBM about possible joint ventures on REMS research. 

Joy Technologies, Inc. and the USBM have a Cooperative Research and Development

Agreement (CRADA) to investigate and develop technology for advanced computerized

mining systems. The initial area of the cooperation has been for the development of a

proximity warning system for human safety around mobile mining equipment. This system

has been made commercially available by Joy.

Joy has also requested assistance to investigate the development of automatic cutting for

a highwall mining machine. It wishes to incorporate coal-overburden boundary detection,

rib thickness sensors, and automatic cutting cycle into a control system for its Addington

highwall mining system. The USBM will apply their expertise to help solve these

problems. This effort was initiated in 1993.

The incorporation of REMS technology into the mining industry will be gradual and

evolutionary. Cooperative research agreements are being established that apply machine

guidance technology (both heading and in-seam) and visualization systems to increase

productivity of highwall operations. At least three highwall mining operations or suppliers

of equipment are actively requesting information on REMS.

Reduced Exposure Mining System Page 19

Impacts of Advanced Technology

in Parallel Industries

Smelting

Because of hazards associated with smelting, steel mills have introduced filtered control

rooms for workers in these areas. This is done in order to remove workers from the

smelting area itself, which contains hazardous fumes. The control rooms have clean air

pumped in, enabling the workers to perform tasks while increasing health and safety on the

job. 

Tunneling 

Tunneling is an underground operation similar to underground coal mining in that a

material is cut and transported and, if the roof is not substantial, it must be supported. Thus,

while there has been some use of automation in tunnel-boring machines in large tunneling

operations, there is potential application of REMS to tunneling. The U.S. Bureau of Labor

Statistics found that the accident rate per 200,000 person-hours for underground workers

in tunneling was twice the accident rate of workers in manufacturing and almost twice the

accident rate of aboveground construction workers. 

Recently, a mini-miner used in underground mining was modified and is being used in

tunneling projects. The technology developed for REMS should have some application to

tunneling equipment like the mini-miner and possibly to haulage of waste and roof support.

Removing workers from the hazardous face area is as important in tunneling as it is in

underground coal mining. Glover claimed that tunneling has a higher proportion of 5

accidents than any other branch of civil engineering. The equipment developed under the

REMS project will contribute to safety in this environment. 

Reduced Exposure Mining System Page 21

Spin-off Technologies Both for Mining

and Other Industries

Since the inception of the research program on REMS, USBM researchers recognized the

potential benefits of spin-off technologies that evolve from this work. As technologies are

developed and refined to achieve computer-controlled mining, industry can begin to apply

them to existing underground mining methods and equipment. Thus, short-term gains from

a long-term research program can be realized. 

Listed below are several of the more important and most beneficial spin-off technologies

that will be available within three years:

Coal Interface Detection Sensors

In recent years, the Coal Interface Detection (CID) research program has developed a

number of methods for determining the thickness of coal left on the roof, the coal roof-rock

or coal floor-rock boundaries, and the thickness of coal pillars. 

In situations where all of the coal is taken—but it is undesirable to cut and remove the roof

or floor rock—a different technique for detecting the coal-roof interface and controlling the

cutting of coal is needed. The USBM has developed an infrared technique to detect this

coal-rock boundary under these conditions. An infrared viewing camera and imageprocessing intrusion alarm have been successfully used to indicate the point where the host

rock is just barely being touched by the mining machine bits. This infrared system is ready

for application now and several mining companies have shown an interest in adopting it.

An alternative would be to use electronically detected vibration picked up by a roof bolt.

Highwall mining requires accurate control of the pillar wall of coal between adjacent

entries. The deeper one can penetrate into the coal seam, the more efficient the operation

becomes, enabling more coal to be removed. Coal is wasted if the separations are too wide,

and mines can collapse on the machine if the walls are too thin. 

The USBM has successfully modified a commercial pulse radar system to perform

measurements of the coal wall thickness. The output can be used as feedback for the

operator so that the direction of the machine can be altered to maintain a parallel entry at

the correct minimum thickness. Highwall mining companies are actively engaged in

working with us to get this product on their machines. 

In the near term, the mining industry will have a device to aid it in making consistent and

repeatable roof and floor cuts, as well as a device to measure rib thickness between cuts.

Advantages of equipping a machine with seam-tracking capability include higher coal-bed

extraction, reduced dilution by minimizing roof/floor material taken, increased coal-cutting

rates, reduced machine maintenance (due to reduced rock-induced vibration), and reduced

respirable quartz-dust concentrations (due to the reduced cutting of roof and floor rock). 
Page 22 Reduced Exposure Mining System

The USBM research program is also developing a novel radar technique that can identify

differing strata layers or objects for distances of up to 9 m (30 ft) into the ground. With this

system one will be able to look ahead of mining operations to detect voids, gas well pipes,

etc. It can be used to investigate strata layers to determine proper roof bolt lengths. 

It also has the ability to examine concrete roads, bridges, walls for structural changes, and

can provide a general-purpose, through-the-earth imaging instrument for detecting

unexploded ordnance and nuclear waste as well as for imaging the condition of our nation's

highways, locks, dams and bridge structures. 

The USBM has conducted an extensive study of coal and host rock properties, especially

for their gamma emission rates. Armed with this information, researchers are able to offer

mine companies guidance in determining whether the now-commercially available natural

gamma coal thickness sensor will work for them and how the systems can be implemented

in their mine.

Machine Diagnostics

The USBM has been actively pursuing the development and application of expert system

technology to diagnose and predict maintenance for mining equipment. Equipment

maintenance accounts for a significant portion of lost production in underground mining

operations. Discussions and feedback from industry experts rank this as a top priority for

increasing equipment efficiency and utilization. 

Implementation of REMS will introduce a new level of machine complexity that will

require special skills for maintenance and support. By using well-designed, on-board

diagnostics systems, less training will be required to maintain REMS. The time to identify

the cause of malfunctions and repair the systems will be greatly reduced. Most importantly,

diagnostic systems will permit scheduled and preventive maintenance in safe areas of the

mine.

Two prototype expert systems have been completed. A hydraulic diagnostic maintenance

expert system analyzes data from machine-based sensors to diagnose system component

problems and failures. An electrical diagnostic expert system was developed as a userinteractive troubleshooting guide for mine electricians. Both systems provide a powerful

means for improving equipment maintenance by allowing maintenance personnel to quickly

diagnose malfunctions and recommend appropriate repairs. 

The concept and benefits of this research are applicable to all machines, regardless of how

they are operated. Because REMS provides an onboard data communications network,

acquisition and analysis of sensor data will be even easier, but the network is not a

prerequisite to implementation of diagnostic systems.

Another diagnostic system, able to predict the failure of the large electric motors used in

mining equipment, is being perfected. Current and voltage sensors are placed on the power

wires leading to the motor, allowing signals to be analyzed and the condition of the motor

to be assessed. Motor failure is a leading cause of machine downtime, and early detection
Reduced Exposure Mining System Page 23

of impending failure will allow preventive maintenance to be scheduled, increasing

machine availability. 

Worker Safety Devices

USBM experiments with REMS during the research and testing phases require a person to

handle the mining machine cable while the machine is under computer control. The USBM

concern for that person's safety and the need for him or her to be able to stop the machine

or indicate readiness of the coal haulage system, led to the development of a remote control

system. This uses an MSHA-approved, two-way voice radio equipped with a touch-tone

controller. The handheld device provides override control of several critical continuous

mining machine functions, including the ability to pause or terminate machine operation

instantly. In addition, it allows the operator to talk to the researchers located in the section

control center, thus providing an added layer of safety. The device can be retrofitted to

most underground mining machines and used as a safety mechanism to prevent accident and

injury to face personnel.

Also, because of the increased use of radio remote-controlled mining machines, and

because of the safety issues of persons being around computer-controlled equipment, the

USBM research team developed a proximity warning and machine shut-down system. This

system detects when a person is too close to the mining machine and prohibits the machine

control until he or she gets safely away from the machine.

Navigation and Mine Mapping Technology—Cyclone Sensor

Developed with the intention of detecting local obstacles and navigating/mapping mine

geometries for guidance, it is receiving interest as a post-mining survey and mapping tool.

Software development to support representation of cyclone sensor data is ongoing.

Eventual use would be for semi-automated generation of accurate maps of mine workings.

This will make for better recovery of valuable mineral resources and prediction of mine

boundaries, faults, wells, and other anticipated seam obstructions.

Multipurpose Underground Teleoperated Tracked (MUTT) Scout and Survey Vehicle

A small remote-controlled vehicle was built to take video equipment and other types of

instrumentation into areas where it is unsafe for humans to travel. It is receiving interest

by highwall miners who want to inspect entries for voids, coal seams, environmental

conditions, and the like. It is also seen as a vehicle to assist mine rescue teams in mine

inspection and recovery efforts. 

Roof Bolter Technologies—Bolter Module

Roof cave-in in production sections of a mine is the largest contributor to worker deaths and

injuries. Today's bolter operators must be located at the point of operation of the roof

bolting machine, a location particularly vulnerable to this hazardous condition. The bolter

operator is also exposed to injury while manipulating the drill rod, resin cases, and bolts.
Page 24 Reduced Exposure Mining System

One critical component of the REMS is the computer-assisted roof bolter. An interim

development will be the radio or tethered remotely controlled bolter. Remote control

eliminates the necessity of workers near an unsupported roof and eliminates the need to

handle bolts, drill steel, etc., all of which carry risk of injury. The operator will have to be

within line-of-sight of the roof bolting machine in order to control its operation. The

advantage is that the bolter operator can perform his or her job function at a safe distance

from the unsupported roof. The computer-assisted bolter can operate as a stand-alone piece

of hardware. The most difficult research, the automated bolter module, is currently under

intensive development.

Smart Drill 

Manual control over the drilling of roof bolt holes has been shown to be less than optimal

by all but the most experienced roof bolter operators. Also, with the drive to remove the

worker from the vicinity of the bolter, a means must exist to provide the drill with the

proper thrust and speed control as differing layers of strata are encountered. 

The Smart Drill monitors drilling thrust, torque, and rotational speed. This information is

processed and the thrust and speed are controlled to maximize drill bit life and drilling

efficiency. The measured parameters are also being used to identify boundaries and types

of immediate strata. Strata knowledge will be used to improve bolting patterns and length

selection. 

Although essential for computer-assisted bolting, the Smart Drill can aid manual bolting as

well, since it provides better drill control than humans and measures strata properties hidden

from the human operator.

The drilling control elements for a Smart Drill will be available within 2 years; the strata

identification feature will be available in 3 years. 

Miner-Following Haulage

The REMS will couple the continuous haulage movements with the mining machine. A

spin-off will be a system that will connect the haulage to a standard remote-controlled

continuous mining machine. This will reduce the need for handling heavy power cables and

water lines. Cable handling is a leading cause of back injuries in underground mining. In

addition, it will increase equipment mining efficiency and production since time will not

be lost waiting for haulage vehicles.

Ventilation Systems for Deep-Cut Mining

Ventilation systems with the ability to bring fresh air to the working face when the mining

machine and continuous haulage systems are performing deep cuts, is a stand-alone

technology. It is applicable when the mine chooses to perform deep cuts or break-to-break

cuts, an increasingly popular mining practice. Its development has been accelerated owing

to its use in the REMS. 
Reduced Exposure Mining System Page 25

Environmental Monitoring

Deep-cut mining methods are compelling the USBM to develop airflow and methane

monitoring systems to ensure adequate dilution of methane at the face and adequate airflow.

The dust scrubbing systems found on continuous mining machines are effective in moving

air across the face and diluting methane. As they become plugged with dust, the airflow

decreases. 

The USBM has developed technology alerting operating personnel when the dust scrubber

becomes clogged. Also being developed are dual-head methane monitoring systems, which

provide a better measure of face methane concentration and a more effective ventilation

system to dilute methane encountered while mining. With the probability of reduced

exposure systems on the horizon, such monitoring technology becomes essential, and its

development has been accelerated for this reason.

Reduced Exposure Mining System Page 27

Summary

The advent of advanced computerized technology is inevitable. The REMS is in a unique

position compared to other industrial automation; its major emphasis is to save lives and

minimize permanent human suffering. Its effect on the number of mine jobs will be

minimal; the major effect will be redefining the job of a face worker. USBM research

efforts serve to bring this technology to the mining industry more promptly than if left to

the industry itself, with minimal resources for research. USBM research also brings this

technology openly and equally to all manufacturers of mining equipment. Through

cooperation with manufacturers, the USBM ensures that the technology is sound and meets

the needs of its customers.

Reduced Exposure Mining System Page 29

Acknowledgment

The authors wish to acknowledge Frank Catanzano of Mangus-Catanzano, a consultant who

proved critical to the success of this document. He provided us with the perfect audience

representing the general public to whom we wished to address the document. His

comments on content, and format and editing suggestions were invaluable.

Reduced Exposure Mining System Page 31

1. Wooten, Ronald, Safety Vice President for Consolidation Coal Co. - Testifying on

behalf of the NCA, Senate (House Oversight Hearings, May or June, 1990) as reported in

Coal Outlook, July 30, 1990, p. 6

2. Frantz, R. L. and R. H. King. Study of the Human Factors Aspects of an Automated

Continuous Mining Section (Grant SO144115, Pennsylvania State University). Final

Report, 1977, 387 pp.

3. Kumar, U. Human Reliability and Its Impact on Mechanized and Automated Mining

Operations. Proc. Inter. Symposium On Mine Mechanization and Automation: Volume

II. L. Ozdemir, R. King, and K. Hanna (eds.), Denver, CO, June 10-13, 1991, pp. 16-1 -

16-8.

4. Ayres, R. U. and M. Miller. Robotics and Flexible Manufacturing Technologies: 

Assessment, Impacts, and Forecast. Noyes Publications, 1985, 443 pp.

5. Glover, E. F. Safety in Tunnels. World Tunnelling, Volume 3, Number 5, 1990, pp.

352 and 355.

References

Reduced Exposure Mining System Page 33

ADDENDUM

The Pittsburgh Research Center: History and Scope

Mining Robotics Development Laboratory

Reduced Exposure Mining System Page 35 

 

The Pittsburgh Research Center: History and Scope

n 1910, THE NEWLY CREATED U.S. BUREAU OF Mines I(Act of Congress 36, Stat. 369, March 16, 1910) acquired

a 38-acre tract of land at Bruceton, PA, about 13 miles

south of Pittsburgh. This property included a small coal mine,

later to be known as the Experimental Mine. The objective was

to use this mine for the large-scale underground research

needed to support one of the Bureau's main initial

functions—to provide the mining industry with safer coal mine

explosives. In 1917, when the Center's headquarters moved

from the Government Arsenal in the Lawrenceville section of

Pittsburgh to the Central Experiment Station at 4800 Forbes

Avenue, Pittsburgh, PA, the explosives research and testing

activities were transferred to Bruceton. Subsequent land acquisitions increased the area of the Bruceton Explosives Testing Station to nearly 250 acres. However, for many years the

Center's activities remained headquartered at Forbes Avenue.

Passage of the Federal Coal Mine Health and Safety Act of

1969 marked a major broadening of the Center's mission. To

the longstanding programs on fires, explosions, and explosives, research was added or expanded to control respirable

dusts and other atmospheric pollutants encountered in underground mines, reduce noise exposure of miners, decrease

methane emissions, protect against roof and rockfalls, improve

mine ventilation, eliminate a wide range of industrial safety

hazards, and develop new technology for postdisaster survival

and rescue. Conservation and reclamation of mined lands

became another major activity, aimed at such environmental

problems as acid mine drainage, fires in abandoned mines and

waste dumps, and ground subsidence. New mining technologies were investigated to meet the needs of an industry producing under increasingly difficult conditions while remaining

compatible with health, safety, and environmental concerns.

This expansion in program goals was reflected in a series of

administrative mergers that began in 1969 and ultimately led

to the formation in August 1979 of the present Pittsburgh

Research Center.

With these rapid programmatic changes came the centralization of all activities at Bruceton, where space was available

for new installations. Today, the Pittsburgh Research Center

is headquartered at Bruceton, PA. The Experimental Mine has

been expanded considerably and the Safety Research Coal

Mine has been added, where new mining equipment and

procedures are evaluated before transferring them to industry.

Lake Lynn Laboratory, located about 60 miles southeast of

Pittsburgh, became operational in early 1982. Lake Lynn is a

highly sophisticated laboratory that provides an isolated setting

for large-scale explosion trials and mine fire research.

Effective September 1982, the U S. Department of Energy's

coal mining technology program was reassigned to the

Bureau, including the Mining Equipment Test Facility (METF),

a 9-acre installation unique in the United States. A major

feature of the METF is the mine roof simulator, capable of 3

million pounds of force for load tests of various roof supports.

The Wire Rope Research Laboratory became operational in

FY84. Here, research is conducted to improve safety and

economy in the hoisting of personnel and materials in

underground mines. FY92 was marked by the completion of

the Mining Robotics Development Laboratory, with state-of-theart equipment and instrumentation for microcomputer,

mechanical, radar, navigation, and strata sensor development.

It also contains a large, open high-bay area for full-scale

evaluations of computer-assisted mining systems.

It has been a long path from the Center's first tentative

approach to coal mine fires and explosions, but is has been a

steady and consistent one. It promises to remain so, well into

the 21st century. 

Reduced Exposure Mining System Page 37

Computer-assisted mining

will reduce injuries and

increase mining 

efficiency.

Mining Robotics Development Laboratory

The U.S. Bureau of Mines has taken the lead in the development

of high technology to enhance the safety and health of mineworkers

and to improve mining efficiency.

HE MINING ROBOTICS DEVELOPMENT Laboratory T(MRDL) was established to provide the advanced

robotics technology needed to maintain a viable mining

industry for our Nation in the future. Located at the U.S.

Bureau of Mines Pittsburgh Research Center, MRDL is the

only facility of its type in the world dedicated to mining robotics

research.

FACILITIES

The MRDL contains state-of-the-art equipment and instrumentation for microcomputer, mechanical, radar, navigation,

and strata sensor system development. A large, open highbay area allows full-scale evaluations of mining systems. A

block of simulated coal is also available for cutting tests.

Computers—including PC's and 3-D graphic workstations—

and software are used to soft-prototype new technology so

that it can be analyzed and refined before development.

Simulation and animation allow researchers to conduct

experiments in software in advance of full-scale tests.

Computers are also used to synthesize complete mining

systems before actual integration. Standardized hardware

and software allow concurrent engineering of technology at

multiple research centers.

RESEARCH GROUP

The MRDL has a multidisciplinary group of researchers providing capabilities in sensor development, artificial intelligence,

computer-aided design,

computer system development, system integration,

and machine modification.

Partnerships with Carnegie

Mellon University's Field

Robotics Center and the

National Institute of Standards and Technology's Robot Systems Division allow

exchange of ideas, technology, and human resources.

TECHNOLOGY DEVELOPMENT

MRDL research is developing essential technologies for computerized mining:
Page 38 l U.S. GOVERNMENT PRINTING OFFICE 1994-609-003/05018 Reduced Exposure Mining System

Computer-assisted mining systems allow the relocation of

workers from the hazardous mineral extraction area to a

safe, protected location.

Computers are used for modeling and simulation of

robotics technology.

Research has led to the first

ever hands-off, computercontrolled, underground coal

extraction system.

 FOR MORE INFORMATION

 For more information on MRDL, 

 please contact:

 Research Supervisor

 Electrical and Electronics Systems

 U.S. Bureau of Mines

 Pittsburgh Research Center

 Cochrans Mill Rd.

 P.O. Box 18070

 Pittsburgh, PA 15236-0070

 Phone: (412) 892-6633

 Fax: (412) 892-6764

Strata Sensing. Strata sensors are required to keep the cutting CAPABILITIES

of a mining machine within the desired boundaries of a mineral

reserve and to accurately assess mine roof conditions for Unique facilities and researchers experienced in the

placement of roof support. Technology under development development of robotics technology for mining bring

involves machine vibration, natural gamma radiation, synthetic capabilities that can be applied to other industries, including

doppler radar, and infrared thermography. infrastructure

Navigation and Guidance. Information on the location of waste cleanup, and extramining equipment within mine passageways is needed to terrestrial mining.

control its movements. A laser-scanner and a laser gyroscope

system are being developed. The laser gyro is a high- We technically represent

technology guidance system successfully applied in the the Federal Aviation

military. Ultra-sonic sensors are used to detect obstacles. Administration on a grant

Machine Health. Computerized maintenance systems utilizing

expert systems and adaptive learning networks are being

developed for the hydraulic, electrical, and electrical motor

systems of mining equipment.

Computer Systems. Computer systems that coordinate the

actions and motions of mobile mining machines are being

developed using standardized techniques used in the U.S.

space program.

Research is also being conducted on other technologies,

including voice recognition, stereoscopic visions systems,

teleoperation, and automated roof bolting modules.

RESEARCH HIGHLIGHTS

Research has led to the first ever hands-off, computercontrolled, underground coal extraction system.

The prestigious R&D 100 Award was received for the

development of a radar strata thickness sensor.

A Cooperative Research and Development Agreement

(CRADA) with Joy Technologies, Inc., allows efficient transfer

of robotics technology to the mining industry

improvement, hazardous

to Mellon Institute to

develop a robot for aircraft skin inspection, and

Westinghouse Hanford Co. on robotics technology for waste

removal and remediation at the U.S. Department of Energy’s

Hanford facility.