THE DESERADO MINE MONITORING AND CONTROL SYSTEM 

Jul i e Mi tchell 

U.S. Department of Interior 

Bureau of Mines 

Pittsburgh Research Center 

Pittsburgh, PA. 15236 

Len Eros 

Western Fuels-Utah Inc. 

Deserado Mine 

Rangely, CO 81648 

Robert King 

Colorado School of Mines 

Mining Engineering Department 

Golden, CO 80401 

ABSTRACT 

The Bureau of Mines has studied the Deserado 

Mine computerized monitoring and control 

system, located in Rangely, Colorado, to 

acquire knowledge about the overall costs and 

benefits of mine monitoring systems. 

The Deserado system is a complex system 

monitoring envi ronmental parameters, 

electrical power, and operation of all mine 

equipment, and controlling the entire conveyor 

haul age system. 

This paper discusses the evaluation of the 

Deserado monitoring system from initial design 

through system installation and operation. It 

also examines the costs, benefits, and 

performance of the monitoring system. 

INTRODUCTION 

The Bureau of Mines (Bureau) has a mandate to 

support the Federal Coal Mine Health and Safety 

Act of 1969 (PL 91-173), and the subsequent 

Federal Mine Safety and Health Amendments Act of 

1977 (PL 95-164). These Federal laws require that 

the air quality in underground coal mines be 

maintained and control 1 ed at specific 1 eve1 s . 

In pursuit of this mandate, the Bureau has 

sponsored projects investigating computerized mine 

monitoring. The objective of these projects is to 

provide the miners with a more efficient, reliable 

means to comply with the regulations and to 

increase mine safety. 

The Bureau received a request from the Western 

Fuel s Association (WFA) for information on remote 

monitoring and control systems for underground 

coal mines. An initial meeting between WFA and 

the Bureau was held on March 12, 1982, at the 

Pittsburgh Research Center (PRC). WFA was in the 

process of developing the Deserado Mine, a large 

and compl icated underground coal mine, and was 

interested in incorporating a computerized 

monitoring and control system into the mine plan. 

WFA saw this as essential to operating with the 

highest level of safety while producing coal in 

the most cost efficient manner. 

In June 1982, the Bureau and WFA establ ished a 

memorandum of agreement for the Bureau to lend 

expert assistance to WFA in planning the design 

and speci f i cat ions for a computerized mine 

monitoring and control system. In return, the 

Bureau could document and evaluate the operational 

experience and benefits of the system. 

The Bureau's objective was to validate much of its 

mine monitoring research in a large-scale mine 

complex. The documentation and evaluation of cost 

versus benefits and technical performance would 

provide assistance to other mines interested in 

this type of project. Important information would 

become available on all phases involved in the 

design, installation, and operation of a 

computerized mine monitoring and control system. 

The Bureau contracted the Colorado School of Mines 

to perform the evaluation by collecting 

information through regular mine visits. 

DESERADO MINE DESCRIPTION 

WFA's Deserado Mine is located near the western 

border of Colorado, approximately 8 mi 1 es 

northeast of Rangely. It supplies coal to the 

Bonanza Power Plant located near Bonanza, Utah. 

The power plant is operated by Deseret Generation 

and Transmission and uses a 400-MW power 

generator. The plant has been designed for the 

addition of a second 400-MW unit in the future. 
Ground was broken at the Deserado mine site on 

August 28, 1981. The Deserado Mine extracts coal 

from a seam called the D seam, which averages 

7 ft. Access to the seam is by a 400-ft-long, 

two-compartment slope entry whose depth at the 

bottom is 100 ft. The deepest point of the mine 

lies 1,300 ft beneath the surface. 

The slope was completed and the first continuous 

miner was taken underground in October 1982. At 

completion of initial development Deserado wi 11 

produce coal using one longwall and two continuous 

miners at a production rate of 1.35 mill ion tons 

per year (TPY). Presently, the mine is using four 

continuous miners, including two for longwall 

panel development, at a production rate of 

approximately 0.96 mil 1 ion TPY. They currently 

work two production shifts and one maintenance 

shift per day, 5 days a week. Longwall operation 

is scheduled to begin by December 31, 1986. 

A belt conveyor haulage system is used to 

transport coal from the working section out of the 

mine. Electric-powered, rubber-tired shuttle cars 

are used for face haulage. Rubber-tired diesel 

vehicles are used to transport miners and 

supplies. There are no tracks in the mine, except 

along the slope for the hoist. The upper 

compartment of the two-compartment slope entry 

contains the conveyor belts. The lower 

compartment is used to transport men and material 

in and out of the mine and also serves as a 

ventilation intake. 

Coal moves from the mine portal to one of two 

10,000-ton raw coal silos and then to a 750-tonper-hour (TPH) preparation plant. Clean coal is 

transported via a 3- 1/2-mi le overl and conveyor to 

a 25,000-ton slot storage facility and rail 

loadout. The final 35 miles to the power plant is 

by an electrically powered train. 

DESIGN CONSIDERATIONS 

Design considerations and requirements specified 

during the planning stages helped dictate the 

fol 1 owing architecture for the Deserado Mine 

monitoring and control system. 

1. Com~atibilitv - The mine monitoring system had 

to be compatible with an existing preparation 

plant system. This system monitored and 

control 1 ed the preparation plant activities, an 

overl and conveyor, the main mine vent i 1 at i on fan, 

the mine hoist, and the raw coal system from the 

slope to the top of the silos. The prep plant 

system consists of two A1 1 en-Bradley* PLC-3 

programmable controllers, one of which acts as a 

hot backup, and a Process Control Industries 

D-1200 interface. The D-1200 supports a line 

printer and hard disks for data storage. This 

monitoring system uses three "intelligent" color 

video display terminals (VDTs) and one alarm 

printer for operator interface. Since WFA wanted 

*Reference to specific brands, equipment, or trade 

names is this report is made to facilitate 

understanding and does not imply endorsement by 

the Bureau of Mines. 

monitoring of the raw coal system, the main fan, 

and the mine hoist to be integrated into the mine 

monitoring system, it had to interface to these 

existing sensor points with a minimum of 

reengineering. 

2. Reliability - WFA wanted a reliable system that 

would operate continuously, so dual processors 

were recommended with automatic switchover upon 

fai 1 ure of the primary. An uninterrupt i b1 e power 

supply (UPS) was specified to protect the main 

processor from power fluctuations or power 

failure. It was recommended that the trunk cable 

be looped through two separate, para1 lel entries 

to prevent communication failure in the event of a 

break in the line. 

3. Information Manaqement - A supervisory computer 

was recommended to provide data storage, analysis, 

and reporting, and to tie together the complete 

mine complex by accepting data from both the mine 

monitoring system and the prep plant system. 

4. State-of-the Art - The mine monitoring system 

was to be a proven, state-of-the-art system and 

was to provide good, interactive color graphics. 

5. Flexibilitv - The mine monitoring system was to 

be flexible enough to monitor a wide variety of 

sensor inputs from the mine, involving many 

controllable points. It also had to be user 

friendly to allow mine personnel to update the 

system. The monitoring system had to be designed 

so that the be1 t conveyors and other critical 

production equipment could still be operated in a 

manual mode. 

On April 27, 1984, WFA awarded Conspec Controls 

the contract as the successful bidder. Initial 

installation was scheduled to begin August 1, 

1984, and the monitoring and control system was to 

be completely installed, tested, and handed over 

to WFA by October 1, 1984. The initial system 

would include the mine monitoring control 1 er, hot 

backup, supervisory computer, software, telemetry 

system, and sensors to monitor the mine at its 

current state of development . Additional sensors 

and hardware would be purchased and installed as 

the mine developed. The vendor was responsible 

for instal 1 ation, cal i bration, and startup 

procedures for the new system. The monitoring 

system was sold as an inclusive package with a 

total price of $387,420. 

MINE MONITORING AND CONTROL SYSTEM DESCRIPTION 

The system performs six monitoring and control 

functions. Two of these were transferred from the 

prep plant system, as discussed before. The four 

new underground functions i ncl ude be1 t f i re 

monitoring, power center monitoring, environmental 

monitoring, and underground belt monitoring. 

Figure 1 shows the system architecture. Each new 

function is discussed next. 

1. Carbon monoxide (CO) sensors were specified for 

placement at 1,500-ft intervals along the beltways 

for fire detection. The status of the fire 

75 suppression system, located at each underground 
Color Supervisory Color 

computer Graphics I 

I 

pii-~l~\ storage 

monitoring 

Belt fire 

monitor 

---------- 1 Overlond I I Power center I conveyor I---! 

I system I I L - - - - - - - - - , 

I Raw coal I I system I '----------A 

--j Color 1, 

I 

rrn j : plant I---I 

:-:y_s~e_m---: j 

I 

r------- Slot 1 I storage I---' I system I L - - - - - - - - 

KEY 

----- Original prep plant system 

New mine monitoring system 

Fig. 1. Monitoring System Architecture. 

belt drive, is also monitored. Eight CO sensors 

were initially installed. In the future WFA plans 

to petition MSHA for a variance so that the 

beltways can be used to provide fresh air to the 

working face. 

2. Power center monitoring is accomplished through 

the use of electrical power (wattage) sensors at 

each underground power center. These wattage 

sensors give an indication of the equipment status 

and can be used to determine equipment run time. 

Equipment monitored includes continuous miners, 

shuttle cars, and roof bolters. The longwall will 

also be equipped with power sensors. Ground fault 

and phase fault sensors at the outside 

substation are monitored, as is circuit breaker 

status at each underground power center. Each 

power center has seven sensors. Two power centers 

were initially monitored and three more will be 

monitored in the future. 

3. Environmental monitoring packages are in place 

at two return air locations and one intake air 

location to check the status of the air quality 

and quantity. Each environmental package consists 

of an air velocity sensor, a CO sensor, and a 

methane (CH4) sensor. Some environmental sensors 

were set up individually throughout the mine 

a1 so. The air velocity sensors measure 50 to 

3,000 feet per minute (FPM) airflow, the methane 

sensors 0 to 5% CH4, and the carbon monoxide 

sensors 0 to 50 parts per million (PPM) of CO. 

4. Among other things, underground conveyor be1 ts 

are monitored for belt speed, motor and bearing 

temperature, coal flow rate over the main belt 

scale, pull cord, plugged chute, belt slip, be1 t 

stoppage, misal ignment, tension, and 1 ocal 

lock-out. The mine monitoring system has the 

ability to remotely control the starting and 

stopping of the conveyors, with the option for 

local, manual control for offshift work or should 

the computer fail. The monitoring system monitors 

300 points at 10 underground belts. Sensor 

locations are shown on the mine map in figure 2. 

The mine monitoring and control system gives the 

current mine status on a color VDT and on a 

printer. Analog points are read in standard 

engineering units. The system allows alarm 

setpoints to be established on the surface. 

Alarms are indicated on the operator's terminal 

and alarm printer. An alarm horn and light 

responding to CO alarms are at each underground 

outstation. The mine monitor processor has 64K 

RAM memory in which the programs are stored and a 

256K floppy disk drive. The system can accept a 

maximum of 800 data inputs. 

Although the prep plant and mine monitoring 

systems operate independently, a supervisory 

computer communicates with and receives input from 

both systems. The supervisory computer handles 

data archiving, extensive data analysis, color 

graphics generation, and system control . It 

consists of a 16-bit processor with two 20-Mbyte 

hard disks. Reports document run time, production 

and environmental status, alarm summaries, 

historical 1 ogs, trend analyses, and equipment 

availability. The supervisory computer displays 

information on two color VDT's and a report 

printer. Graphic displays from both the mine 

monitoring system and the prep plant system are 

possible on either color VDT. The color graphics 

system permits the cursor on these displays to 

control the underground mine belts, but not the 

prep pl ant equi pment . 

There is also a color VDT in the administration 

building for status monitoring of the two systems. 

An alarm printer, horn and light in the guard 

shack a1 1 ows for the detection and acknowledgment 

of alarms when the mine is idle. 

INSTALLATION 

According to the original time schedule, 

installation was to be complete by October 1, 

1984. This date was not met and has continually 

been delayed by Conspec. The delays and other 

installation experiences are discussed below. 

One cause for the delay in the installation of the 

system was lack of communication and understanding 

between the vendor and the installation 

subcontractor. The subcontractor was not aware of 

the underground work requi rements. Their 

personnel had not had the 40-h MSHA underground 

76 mine training for electrical certification. Mine 
EAST MAINS 

Portal and 

intake air 

Fig. 2. Mine Map with Sensor Locations. 

ua. 

I I w 0. cn 

z_ 

a 

I 

I- In 

hazard training required an additional 8 h, and 

two 4-h sessions were needed to familiarize the 

subcontractor with the mine's layout and 

procedures. Many del ays were experienced because 

of conflicts between normal mine operations and 

the subcontractor's work. Further delays occurred 

when it was necessary to borrow equipment from the 

mine because of inaccessibility to the 

subcontractor's main office in New Mexico. 

= y MA .m SOUTH SUB MAINS 

East portal KEY 

CO sensor 

CO fire sensor 

0 Belt sensor 

A Methane sensor 

Slope A Air velocity sensor 

Power center sensor 

0 

Instal 1 ation of the CO monitors presented some 

problems and occasional other, though 1 ess 

serious, delays. .Fol lowing vendor's drawings the 

CO monitors were placed 2,000 ft apart along the 

be1 tways. The initial specifications called for 

1,500 ft spacings. When the error was discovered, 

2 h were lost in correcting it. Mounting 

instructions did not specify that the sensor cell 

was to be located at the bottom of the sensor 

housing and the transducers were mounted on their 

side. A full shift's work was required in 

fabricating new brackets and remounting. 

Many problems and delays during instal lation might 

have been avoided if a vendor representative had 

been present during the entire installation 

period, instead of only at the very beginning and 

on a call basis. Conspec made several site trips 

during the installation at WFA's request. 

WFA had planned acceptance tests immediately after 

instal 1 at i on, but because the problems and delays 

prevented completion the system started in phases 

rather than all at once. As of June 1, 1986, 

Conspec still had not completed instal lation: The 

supervi sory computer, due for completion November 

30, 1984, remains incomplete. The problem lies in 

the report generation software and the color 

graphics software. The vendor has now supplied 

WFA with a Compaq PC to interface to the 

supervisory computer for report generation. Color 

graphics are available from the mine, but only 

static conditions, not current sensor values, are 

being shown from the prep plant system. WFA 

completed the development of color graphics pages 

and sensor calibration. 

OPERATIONAL EXPERIENCE 

When monitoring system instal 1 ation began, WFA 

hired a mine operations engineer to be responsible 

for its installation, operation, and expansion. 

As the mine and the monitoring system began to 

expand, WFA hired three additional full-time, 

entry-level engineers. The mine operations 

engineer has overall responsibility for the entire 

project. In addition to their primary 

responsibility as system operators, the three 

control room engineers have more speci fi c 

functions. One is responsible for the mine 

monitoring computer, entering new monitoring 

points, developing control programs, calibrating 

sensors, and modifying programs as the mine 

expands. The second is in charge of the 

supervisory computer, developing the graphic 

display and control programs. His goal is to 

place as much of the mine as possible under 

graphic control. The third will develop software 

for the Compaq PC for manipulating data, and 

designing and generating reports for the mine 

manager, mine superintendent, and maintenance 

superintendent. 

There have been no additional costs for equipment 

failure to date because the system remains under 

the original warranty until WFA acceptance. WFA 

engineers have done most of the troubleshooting 

work on the system, thereby reducing outside labor 

costs. Any wiring changes or additions have been 

made by mine electricians. 

Originally, the trunk cable was installed in a 

loop, with each side in a separate entry, to 

provide a safeguard against a possible break in 

the line. The theory was that if one side was 

damaged, the other would still be usable for 

communications. A trunk break detector in the 

loop would alert the operator of the break. A 

problem arose when the break was not clean and the 

line conductors shorted. This interrupted 

communi cat i ons and the para1 1 el 1 i ne became 

77 useless. Therefore, WFA removed the extra line in 

the loop and used it in other parts of the mine. 
Calibration is required for all analog sensors. 

This includes environmental, power consumption 

(wattage), temperature, and amperage sensors. The 

CO and CH4 transducers must be calibrated at least 

once a month. Airflow sensors need be calibrated 

only once every 3 months. The power sensors were 

calibrated prior to installation and again after 

the initial system startup. The temperature and 

amperage sensors in the conveyor belt drives were 

calibrated after installation. 

A problem was encountered when calibrating the 

methane sensors because of their location in 

return airways. The calibration equipment is not 

intrinsically safe; therefore the CHq sensors must 

be disconnected, brought into fresh air, 

reconnected to the trunk line, calibrated, and 

finally returned to their original location. 

SYSTEM BENEFITS 

The main 'benefit of the monitoring and control 

system is in maximizing underground belt 

availability. The be1 ts have been operating on an 

average of 95% of the time. Although historical 

data are not available, workers agree belt 

availability is higher now than before 

installation. If a belt stops, the control room 

engineer knows where and why. Using the mine 

proper ventilation in intake portals and return 

areas near the exhaust fans. Plans include an 

additional five to be placed in the sub mains and 

the longwall panel. Information received from 

these sensors will detect areas not properly 

ventilated and may help find an unknown roof fall 

or badly positioned regulators. 

Methane monitors determine if methane is 

accumulating in an area. There are presently two 

in the returns near the exhaust fan, and two more 

will be installed ne'ar the longwall bleeders and 

at main ventilation intersections. 

MINER AND MANAGEMENT OPINIONS AND ACCEPTANCE 

Management has had high expectations for the 

monitoring and control system. They assumed two 

general benefits would result from the project: 

One was to generate historical data and trend 

analyses to help improve mine efficiency, lower 

electrical costs, and improve maintenance 

troubleshooting. The other benefit would be the 

provision of real time operating data, which would 

help improve efficiency and safety aspects. 

Management had these and other specific goals in 

mind and have been very supportive of the 

78 project. Their attitude filtered to lower 
management levels and eventually to the hourly 

wage empl oyees. Hourly empl oyees 1 earned much 

about the system by asking questions of the 

subcontractors as they were installing the 

hardware underground. Through their questions, 

the miners presented an open-minded view of the 

monitoring system. 

Presently, the hourly mine employees find the 

troubleshooting capabil ities very he1 pful . The 

computer system has been in service for over a 

year and there has been no tampering. Management, 

union officers, and individual employees feel the 

monitoring and control system improves safety. The 

miners look at the computer as just another 

productive mining tool. They value the added 

safety and continue to ask many questions and show 

an interest in the system's capabilities. 

Currently, management continues to support the 

project but has some mixed feelings. Generally, 

they have been pleased with the qua1 ity and 

benefits of the system but concerned over the 

delays. Every phase of the work has been behind 

schedule and improvement seems unl i kely. The 

result has been that WFA has performed much of the 

work contracted to the vendor. 

FUTURE EXPANSIONS AND GOALS 

Presently, 600 points are being monitored on the 

mine monitoring computer, which has a capacity of 

800 points. With present expansion plans, this 

capacity will be exceeded by the end of 1986. The 

installation of a second mine monitor will cover 

the expansions. Presently the computer pol 1 s a1 1 

accessors in less than 3 seconds and should 

continue at this rate when the remaining points 

are added. The graphics system is monitoring over 

1,000 points from the prep plant and collecting 

21,000 pieces of information per minute on hard 

disk. This amount of data is expected to increase 

to 25,000 pieces/minute by yearend. 

The biggest expansion to the monitoring system 

will come with the addition of the longwall panel, 

scheduled to begin producing by December 31, 

1986. The areas of main monitoring interest will 

be the face conveyor, the head and tail gates, the 

crusher, and the stage loader. Temperatures in 

the motor, gearbox, and drive roller bearings will 

be monitored. The motor phase windings, the power 

center, and the pressure in 14 evenly spaced 

shields will also be monitored. 

Envi ronmental parameters wi 11 be monitored at the 

intake and bleeder points to the longwall. Air 

velocity and CO sensors will be placed to monitor 

intake and return air, and CH4 sensors will be 

necessary to monitor return air at the bleeders. 

The pump station that will serve the first four 

planned longwall panels will be monitored and 

computer-controlled for ease of operation. The 

pump station is located 6,000 ft from a longwall 

panel, making it di ff icul t for 1 ongwal 1 personnel 

to access the pump station. The option to control 

the pumps manually will also be available. Water 

levels, bearing temperatures, power consumption, 

and water pressure will be monitored. 7 9 

The Deserado Mine uses an Mine Safety Appliances 

(MSA) rock dust system. Bulk storage on the 

surface is provided by a 140-ton tank. There are 

also four 10-ton tanks located underground. 

Presently, the sequential transfer of rock dust 

between tanks is accomplished manually. This task 

will be automatically controlled and operated by 

the monitoring system. 

The mine has three major, long-range goals for the 

monitoring and control system. The first is to 

reach complete installation of the system and 

continue proper advancement as the mine expands. 

The second is to have control room engineers give 

the graphics system complete control over all 

equipment monitored by the system. The final goal 

is the completion of the supervisory system. WFA 

is excited about the possibilities for lowering 

production costs through improved equipment 

avai 1 abil i ty and improved maintenance. A1 so, the 

increase in safety will keep mine operations 

running smoothly and give miners a safe working 

envi ronment . 

SUMMARY 

The Bureau of Mines and Western Fuels Association 

entered upon a memorandum of agreement to study 

the design, installation, and operation of WFA's 

Deserado Mine monitoring and control system, which 

is one of the most advanced systems in a 

U.S. mine. WFA is pleased with the quality of the 

mine monitoring system and the benefits that have 

resulted from the use of it. 

The major benefit has been the increased 

availability of the conveyor belts. The 

monitoring abilities have greatly helped in 

troubleshooting problems, and the addition of 

report generation is expected to enhance 

preventive maintenance methods. Computer control 

of the belts has increased miner safety. 

Many delays in del ivery and completion of the 

monitoring and control system have occurred. 

However, WFA has been quite satisfied with the 

performance of the system. Both management and 

mine personnel acknowledge the benefits of the 

system and are willing to work at keeping it 

operating smoothly and continue to expand it as 

the mine develops. 

REFERENCES 

1. L. A. Eros and R. H. King. Deserado Mine 

Computerized Monitoring and Control System 

Evaluation. Bureau of Mines contract 30348003; 

Colorado School of Mines, Mining Engineering 

Department, Golden, CO, 1986. Avai 1 able for 

consul tat i on at the Pittsburgh Research Center, 

Bureau of Mines, Pittsburgh, Pa., Jul ie Mi tchell , Technical Project Officer.