Roof Screening for Underground Coal Mines: Recent Developments 

Craig S. Compton, Engineering Technician
 

Sean Gallagher, Senior Research Scientist
 

Gregory M. Molinda, Lead Research Scientist
 

Christopher Mark, Principal Research Engineer 

NIOSH-Pittsburgh Research Laboratory 

Pittsburgh, PA, USA 

Gene Wilson, Manager of Product Development 

J.H. Fletcher and Company 

Huntington, WV 

ABSTRACT 

Falls of small pieces of rock from between roof bolts continue 

to cause fatalities and to injure hundreds of coal miners each year. 

Roof screen is the most effective way to prevent these incidents, 

but some mines are reluctant to use it because they believe 

installing screen can be awkward, expensive and time-consuming. 

The most common type of roof bolting machine used in mines 

today is the dual boom, outside-controlled roof bolter. Mines who 

install roof screen using these machines have developed some 

machine modifications and techniques to ease roof screen 

installation. This paper describes some successful techniques and 

machine modifications that are being used in productive mines to 

assist with roof screen installation. Since the material handling 

involved with roof screen installation can expose miners to an 

increased risk of musculoskeletal injuries, the National Institute for 

Occupational Safety and Health (NIOSH) ergonomists, designed 

machine modifications and implemented a series of tests to 

evaluate roof screen handling procedures for outside-controlled, 

dual boom roof bolting machines. Roof screen installation can also 

have a positive economic impact on a mine by reducing the cost of 

injuries, workers’ compensation, required spot or re-bolting, and 

clean-up of long term travel and belt entries. 

INTRODUCTION 

Hundreds of injuries and usually one or two fatalities occur 

each year due to small rocks falling from between permanent roof 

supports. These small falls are not adequately controlled by 

conventional roof supports like roof bolts, large roof plates, steel 

straps, pizza pans, spider plates, or header boards. The 2005 Mine 

Safety and Health Administration (MSHA) accident data base lists 

list a total of 563 fall of ground injuries, including 9 fatalities. An 

analysis of the database suggests that 466 of the injuries were 

caused by roof skin failures (figure 1). 

The key to controlling falls of the immediate roof or roof skin is 

maximizing the area of roof coverage and confining these relatively 

small loose rocks. Roof screen offers the most coverage of the 

immediate roof. Depending on the size of the screen, coverage of 

up to 94% of the roof area can be achieved (Robertson et al., 2003). 

Screen also offers a first line of defense for roof bolter operators by 

confining or deflecting small rocks that can come loose during 

drilling or bolt installation. Figure 2 shows an example of the 

protection screen provides during bolt installation. 

Figure 1. 2005 Ground Fall Injuries by Fall Type. 

Figure. 2. Screen providing protection during bolt installation. 
 

 

 

 

 

 

 

 

 

 

Although the benefits of screen are well known, mining 

companies in some areas of the U.S., mainly Northern Appalachia 

and the Illinois basin, are still reluctant to use screen on cycle. The 

costs associated with installation, material handling and possible 

ergonomic injuries are delaying the acceptance of screen as an oncycle roof support tool. A few mines however, have decided that 

installing roof screen can be cost effective when compared to the 

cost of lost time accidents, training of replacement workers, or 

going back to clean and re-bolt already developed entries. 

Being aware of conditions that warrant the use of roof screen 

could prevent fatalities, injuries and even improve a mine’s bottom 

line. Local experience is of course the best tool for recognizing 

these hazardous conditions, such as: 

•	 Bolter operators are having problems setting the Automated 

Temporary Roof Support (ATRS) due to irregular or high 

potted out roof, 

•	 The mine roof consists of moisture sensitive fireclay or 

claystone that deteriorates over time, or; 

•	 A mine sees production time losses due to cleaning up of 

outby travel ways to clear loose rock and re-bolt areas 

where plates become loose due to skin failures around 

plates and; 

•	 Regular mine roof damage mapping can highlight problem 

areas and help to anticipate future problem areas, (Molinda 

et al., 2003). 

It has also been suggested that the Coal Mine Roof Rating (CMRR) 

could be used as a guide when considering the use of roof screen. 

If the CMRR of the roof is below 35, installing roof screen could 

help control roof skin failures, and maintain long term stability in 

travel and belt entries (Gadde et al., 2005). 

The paper describes recent developments in roof screen 

installation for underground coal mines, and: 

•	 Evaluates procedures mines have developed to ease the 

installation of roof screen; 

•	 Discusses machine modifications made to ease the 

transportation and installation of roof screen; 

•	 Evaluates devices and techniques developed to assist with 

getting screen over the bolter and into installation position; 

•	 Describes developments being made in machine 

manufacturing to assist with the ergonomics of screen 

installation, and; 

•	 Gives a description of the economic impacts of roof screen 

installation. 

PROCEDURES DEVELOPED AT WORKING MINES 

TO ASSIST ROOF SCREEN INSTALLATION 

The majority of room and pillar coal mines in the U.S. utilize an 

outside-controlled dual boom roof bolting machine, especially in 

seam heights of less than 6 ft. This type of roof bolting machine 

was not designed to store, transport or assist with screen installation. 

Each coal mining company that uses these machines to install 

screen on a routine basis has developed its own procedures and 

machine adaptations to ease the installation of screen panels. 

NIOSH has observed that the best and most efficient technique 

for handling and installing roof screen is simple good house 

keeping and organization. In the most efficient operations the roof 

bolting machines are very clean and well organized; all supplies 

have a designated area on the bolter that can be accessed quickly 

and safely. This is the case whether screen is stored on the bolter 

or along the rib. The supply areas on the section are also very clean 

and organized. Usually the screen will be delivered to the section 

and stored in a cross-cut with good scoop access to allow 

unobstructed loading of screen and to keep the screen flat and ready 

to install. 

Before roof screen can be installed, it must be supplied to the 

bolting machine. The most common method observed in our study 

was to hook a chain to the panels and drag them to the last open 

cross-cut, then lift them up, one or two at a time, and lean them 

against the rib or leave them lying on the mine floor. The operators 

then walk back to the cross-cut and get them as needed. 

Unfortunately dragging the screen panels can damage screen and 

tends to bury them in mud. Broken, bent and muddy screen is 

much more difficult to handle, and is more likely to get caught on 

everything from the rear of the bolter to the ATRS, making it 

harder for the operators to get screen into installation position. 

The most efficient supply method observed was the use of racks 

or rails (figure 3) installed on the bolting machine that are capable 

of holding enough screen to complete the bolting of roof exposed 

from a full cut of coal. Curtain boards, approximately 3 in x 2 in x 

15 ft, are laid between the racks to keep screen from sagging onto 

supplies. 

Figure 3. Rack used to hold and transport screen. 

The storage racks, some originally designed to hold steel straps, 

are built between 18-22 in above the bolter deck. They must be 

high enough to allow access to bolting supplies stored underneath, 

but low enough to keep them from dragging on the roof of the mine. 

These racks are angled upward, or have a post protruding on the 

ends, to keep screen in place while tramming between places. 

When storage racks are used, screen panels can be supplied to 

the bolter in several different ways. At one mine the scoop operator, 

sometimes assisted by the person installing ventilation curtains, 

loads panels onto the top of the scoop to keep them from being 

damaged and out of the mud. The screens are then transported to 

the last open cross-cut and leaned against the rib. While tramming 

from one face to another, the bolting machine is stopped. Both 

bolter operators then load the screen, one or two panels at a time, 

onto the storage racks. This takes only a couple of minutes to 

accomplish. Leaning the panels against the rib means the roof 

bolters do not have to bend over as far to lift the panels, therefore 
decreasing the amount of exertion needed to lift the panels onto the 

machine. 

An even more effective method used at this mine is for the 

scoop operator, with the help of the ventilation person, to pull up 

immediately behind the roof bolter and load the panels directly 

onto the racks on the bolting machine while the bolter operators are 

installing bolt. This lets the bolters move directly to the next place 

without delaying, to load screen. Both of these supply procedures 

worked very well and the one used was determined by how busy 

the scoop operator was during a particular shift. 

INSTALLATION TECHNIQUE WITH ROOF 

SCREEN STORED ON THE BOLTING MACHINE 

The installation technique observed where racks were used to 

store screen panels on the machine worked seamlessly with an 

experienced crew. The operators would also use the stored screen 

panels as a platform to help rotate and slide the roof screen into the 

installation position. Keeping the screen stored off of the floor 

significantly reduced the amount of bending and lifting usually 

associated with screen installation. Compared to other techniques 

observed, this system appeared to be the easiest and quickest. 

When initiating a new cut it is important to position the 

machine with the ATRS outby the last row of bolts before 

positioning the screen panel. After the screen is secured to the 

ATRS, the machine can be trammed into position to install the first 

row of bolts (figure 4a). After installation of the first row of bolts 

is complete, the following step by step procedure is used to install 

each screen panel: 

Figure 4a. Roof bolter location when ATRS is set and bolts are 

ready to be installed. 

ROOF BOLTER 

Coal 

Roof Bolts 

Unsupported 

Roof 

First row of bolts to be installed. 

ATRS 

Coal 

1. Lower the ATRS and personal canopies enough to allow 

screen panel to be carried over and positioned on top of the 

ATRS with minimal effort. 

2.	 Back the roof bolter up until the ATRS is outby the last 

row of bolts by at least 12 to 18 inches. Total maximum 

distance needed to back up the machine is approximately 

3-1/2 to 4 ft (figure 4b). Backing up is necessary to ensure 

that the operators do not reach inby the last row of 

permanent support. 

3.	 The forward end of the top screen stored on the rack is 

then pushed toward the operator deck-side of the bolting 

machine, minimizing the distance the other operator has to 

reach to get a hold of the screen. The off-side operator 

then walks to the back of the screen, and together both the 

operators lift and carry or slide the screen panel over the 

personal canopies and onto the ATRS. Pre-measured 

marks are put on the ATRS to allow positioning the screen 

correctly and quickly. The marks on the ATRS can be 

adjusted so rib bolts are placed at the desired distance from 

rib. 

4.	 Once in position, the screen is secured by bending over a 

piece of 12-gauge wire that is secured to the ATRS 

(figure 5). This technique holds the screen in position 

until the bolter is moved forward into position and the 

ATRS is set against the roof. 

5.	 When the row of bolts is installed, the ATRS is lowered 

and the 12-gauge wire will pull away from the screen 

panel. The steps are then repeated for each successive 

installation of rows of roof bolts. 

ATRS 

ROOF BOLTER 

Coal 

Unsupported 

Roof 

Roof Bolts Last row of bolts 

Coal 

Figure 4b. Position of roof bolter after backing up so the next 

screen panel can be positioned on the ATRS. 

Figure 5. Roof screen held in position on ATRS with twisted 

12-gauge wire. 

LOW COAL SCREEN INSTALLATION TECHNIQUE 

The following technique has been developed in a mine with a 

seam height too low to use a rack/rail on top of the bolting machine. 

This procedure is slightly slower than previous one, due to having 

to retrieve screen from the cross-cut one at a time. However, 

installation was very smooth with an experienced crew. In a new 

cut, roof screen is attached to the ATRS before moving the roof 

bolter into position for the installation of the first row of bolts 
(figure 6a). After the first row of bolts is installed, the following 

steps are completed: 

1.	 Lower the ATRS and personal canopies enough so the 

operators can reach over them easily. 

2.	 Back up the bolter until the ATRS is approximately 6-8 ft 

outby last row of permanent support (figure 6b). 

3.	 One of the operators retrieves a screen panel from last 

open cross-cut. The operator retrieving the screen will be 

the one closest to where screen is stored depending on the 

entry to be bolted. 

4.	 The screen is then carried by one person along the side of 

the roof bolter and lift it up onto the ATRS. 

5.	 The operator, staying on the outby side of the ATRS, will 

swing the screen panel around the inby side of the ATRS 

and hand it to the operator on the opposing side of the 

machine. Careful attention is necessary at this point. The 

opposing-side operator must avoid going on the inby side 

of ATRS to reach the screen panel. 

6.	 The screen panel is then positioned on top of the ATRS 

and held in place by twisting a piece of 12-gauge wire 

around the screen. 

7.	 The machine is trammed into position and a row of bolts 

installed. The procedure is repeated for installation of 

each successive row of bolts. 

A technique was observed that did not require backing the roof 

bolter up for each panel installation. The procedure is very similar 

to the two previous methods, except that the machine is not backed 

up to allow the screen panel to be fastened to ATRS. Instead a tool 

was made from an old fiberglass roof bolt with a hook fashioned on 

one end. The screen panel is brought up to the front of the bolter 

and laid on top of the personal canopy and the ATRS. The screen 

panel is held in position with this tool while machine is trammed 

into position for installation of the next row of bolts. 

The operators then, using the tool, position the screen on the 

ATRS and raise the ATRS up against the roof where it holds the 

screen panel in position. This works well most of the time, but the 

screen can fall inby if the tool slips off of screen panel. When this 

happens, the operators are tempted to reach inby last row of 

permanent support to retrieve screen. This delays the setting of the 

ATRS and would expose the operator to unsupported roof. In the 

author’s opinion, the time lost by backing the machine up to secure 

the screen panels is minimal, and under no circumstances is it 

recommended that the workers be exposed to unsupported roof 

ATRS 

Figure 6a. Roof bolter location when ATRS is set and bolts are 

ready to be installed. 

ATRS
 

Coal 

Figure 6b. Position of roof bolter after backing up so the next 

screen panel can be positioned on the ATRS. 

ROOF BOLTER 

Coal 

Unsupported 

Roof 

Last row of bolts Roof Bolts 

ROOF BOLTER 

Coal 

Roof Bolts 

Unsupported 

Roof 

First row of bolts to be installed. 

Coal 

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The 

ERGONOMIC STUDIES OF SCREEN HANDLING 

TECHNIQUES 

Using what was learned from observing various roof screen 

installation techniques in the field, NIOSH developed several 

combinations of rails or bars that could be easily retrofitted to 

existing bolting machines. The initial design was tested on a Roof 

Ranger II dual boom roof bolter loaned to NIOSH by J. H. Fletcher 

mpany and later on a full-scale wood mock-up of a outsideed bolting machine built by NIOSH at the Pittsburgh 

h Lab. NIOSH ergonomists designed tests that would 

 different techniques of lifting and carrying roof screen 

n the relative risk of back injury. Each test subject was 

ith EMG (Electromyogram) monitors to measure major 

activity in the arms and torso areas. The subjects also wore 

ar Motion Monitor (LMM) which looks and acts like a 

olumn and is worn as if it were a back pack attached at the 

rs and waist (figure 7). These instruments are capable of 

ng trunk position, velocity, and acceleration in the sagittal, 

nd twist planes of the body (Kotowski et al., 2006). 

initial design consisted of a pair of rails that ran from the 

the roof bolter and ended just before the canopy (figure 8). 

t set of tests was conducted using eight subjects. Test 

 picked up the screen from the back of the bolter and either 

 screen on the rails (RAIL-condition) or lifted the screen 

y (CARRY-condition) up to the ATRS. 

RAIL-condition required an initial lift to get the screen on 

the rails and another smaller lift to get the screen over the canopies 

once the rails ended. Sliding the roof screen on the rails was found 

to significantly reduce the muscular demands of the back and 

forearms compared to carrying the screen. In addition, it was found 

that the test subjects flexed their spines to a greater degree in the 

morning compared to later in the day, which suggests that there 

might be an increased risk of injury when handling screen in the 

morning. However, the rail system used in the first study was 

thought to be in need of improvement due to the fact that the screen 

still had to be lifted over the canopies as the end of the rails was 

reached. It was thought that the rails could be extended so that the 

screen could be slid from the rear of the bolter all the way up to the 

ATRS. The rail system was modified and a second set of tests was 

performed. 
 

 

LMM 

Figure 7. Test subject fitted with Lumbar Motion Monitor 

(LMM). 

SIMULATED 

MINE ROOF 

RAILS TO SLIDE 

SCREEN 

Figure 8. Test subjects sliding screen on rails in first 

experiment. 

Figure 9. Full scale wooden mockup of bolter with rails that 

permit sliding of screen across canopies. 

The second set of tests also involved eight male subjects. These 

subjects had underground experience ranging from actual 

underground bolting experience to men who have only been 

underground a few times. A full-scale wood roof bolter mock-up 

was fitted with a system of rails that facilitated sliding the roof 

screen from the back of the bolter over the canopies and all the way 

to the ATRS (figure 9). 

The tests involved lifting and transporting eight full sheets of 

roof screen up to the ATRS to simulate the requirements for 

screening a typical cut. Three methods of screen 

storage/installation were examined. These included: 1) lifting the 

screen from the ground behind the bolter and manually carrying it 

to ATRS (i.e. rails uninstalled), 2) lifting the screen from the 

ground and sliding it on the rails up to the ATRS, and 3) with 

screens stored leaning against the rib, screens were lifted two at a 

time and stacked on the rails, and from this position the screens 

were slid using the rails to the ATRS. As in the previous tests, 

subjects wore the LMM to assess back motion and risk. The time it 

took to complete the installation of 8 sheets of screen was recorded. 

Results of this study illustrated how slight differences in 

installation techniques can have a significant impact on the risk of 

injury to the lower back. The method of lifting the screen from 

behind the bolter and sliding it on the rails up to the ATRS required 

only 19 seconds to complete. However, this method was found to 

require significant torso flexion (>45 degrees of lumbar flexion) 

during the process of lifting the screen from the ground. The 

manual carrying condition also involved hazardous forward 

bending during the initial lift (again >45 degrees), but also took 

about 3 seconds per screen longer compared to sliding the screen 

on the rails. The two-step process of first stacking the screens on 

the rails and then sliding them one at a time to the ATRS took an 

average of only 8 seconds more per screen than the sliding 

condition. Even with the supply time included, the method avoided 

the risks associated with repeated full flexion of the torso required 

to lift the screen from the ground behind the bolter required by the 

other methods. Maximum forward bending for the latter technique 

averaged less than 25 degrees, which represents a considerable 

reduction in risk for back injury. If the roof screens are supplied 

onto the racks of the machine by supply personnel, then this 

method is not only less risky for the operators, it also becomes 

faster than having screen lying on the ground behind the machine. 

Overall, several conclusions can be taken from these laboratory 

investigations. First, the data show that muscular demands are 

reduced when sliding roof screen on rails rather than manually 

carrying them. This reduced muscle activity indicates lower 

loading of the joints and muscles and a lower risk of repetitive 

trauma injury. Secondly, sliding screens on the rails was faster on 

average than manual carrying. Both of these findings strongly 

support the use of rails and/or racks to assist with screen 

installation. However, lifting screens from the ground when they 

are dragged behind the bolter requires a significant degree of 

forward bending which puts the spine at risk. This risk can be 

reduced if screens are stored against the rib and stacked/stored on 

the rails mounted on top of the machine. 
 

 

 

 

 

 

 

 

 

 

 

RECENT MATERIAL HANDLING INNOVATIONS 

FOR OUTSIDE-CONTROL, DUAL BOOM ROOF 

BOLTERS 

Roof bolter operators are arguably the hardest working persons 

in the mine. They are constantly lifting, bending, pulling and 

carrying materials they need to control the roof of the mine. 

Adding roof screen installation to this already labor intensive job 

increases the risk of stress and strain injury to the operators. 

Material handling injuries continue to sideline hundreds of 

underground workers each year. Lost time material handling 

accidents constituted 33.3% of all lost time accidents in 

underground mining between 2000 and 2004 according to the 

MSHA data base (www.msha.gov). 

In 2000, J. H. Fletcher and Company introduced the walk 

through CHDDR roof bolter with a complete material handling 

system (MHS). The system consists of removable pods for bolter 

consumables, which are hoisted onto the bolter. The system also 

includes a mesh tray that loads and holds roof screen. The mesh 

tray can be moved in eight different directions so it can be moved 

out of the walkway while bolting and also position the roof screen 

for easier lifting during installation to help reduce fatigue. Remote 

control operation also improves visibility for the operator while 

tramming between cuts making it safer for everyone on the section 

(Robertson, et al., 2003). 

J.H. Fletcher and Company now offers a slightly modified 

version of the MHS for the Roof Ranger II roof bolter. The system 

includes a similar pod system for consumables. The Roof Ranger 

II is designed to be used in seams of eight feet or less, so instead of 

a mesh tray, they have designed a Goal Post type of storage rack 

positioned along the center of the bolting machine to store roof 

screen (figure 10). 

Figure 10. Roof Ranger II with Material Handling System 

(MHS). 

The operator deck has been replaced by remote control 

operation. This allows the operator much greater visibility while 

tramming the machine and provides additional room on the deck 

for the material handling system (MHS). A tapered rear deck 

allows a roll off capability of pods. Pods are low profile to fit 

under a scoop ram. A powered winch loads the pods into position 

on the rear deck, the pods are then held in position with pins. 

The machines are equipped with rounded edges on ATRS pads 

and flat tops on the canopies to ease screen positioning during 

installation. There are spring pins mounted on the ATRS outby 

deflector pads to hold screen in position until ATRS can be set. All 

of these modifications are meant to reduce some of the repetitive 

motions and awkward positions roof bolter operators encounter 

routinely while performing their jobs. Reducing the number of lost 

time injuries and transferring difficult tasks from the worker to the 

machine can also lead to higher job satisfaction and improved 

workforce morale. 

THE ECONOMICS OF ROOF SCREENING 

When the best available practices for screen installation are 

employed, together with simple modifications to the roof bolting 

machine, the impacts of screen installation on the overall mining 

cycle can be minimized. For example, Peabody’s Francisco Mine, 

located near Evansville, IN, has routinely installed screen in about 

50% of its drivage since it was opened in 2004. Francisco is also 

one of the nation’s most productive room and pillar mines, with 67 

underground employees producing nearly 1.2 million tons of clean 

coal per year, with a productivity of 6.6 tons/hour (MSHA, 2007). 

Moreover, there are substantial potential economic benefits to 

the use of screen. The most valuable is the opportunity to reduce 

the cost associated with rock fall injuries. NIOSH studies have 

found that a “struck by rock” injury can easily cost in excess of one 

hundred thousand dollars, and a permanent disability could cost 1 

million dollars. Because injuries are so expensive, workman’s 

compensation costs for underground coal mines typically average 

20% to 40% of payroll in the eastern U.S. Industry wide, rock falls 

account for about 10% of these costs, and at many mines the 

percentage is considerably higher. 

A simple example shows how a program of screen installation 

can actually save a mine money. A key assumption is that roof 

bolting is not the bottleneck in the production process—in other 

words, that screen installation can be added without decreasing the 

footage of advance per shift. This situation is not unusual when 

two, double-boom roof bolters are used on a super section (as at 

Francisco). Some other assumptions: 

•	 The section advances 400 ft/shift in a 5-ft thick coal seam. 

•	 Straps, costing $8 per piece, are currently installed in all 

headings and crosscuts. 

•	 Screen installation requires an additional 10 minutes per 

40 ft of advance. 

•	 Screen, costing $16 per piece, will replace the straps in 

50% of the drivage. 

•	 Labor cost (fully loaded) is $40/hr. 

The incremental costs associated with the roof screening program 

can be calculated as follows: 

•	 Cost of screen = $2/ft. 

•	 Cost of labor to install screen = 0.25 minutes/ft two roof 

bolt operators = $0.33/ft. 

•	 Cost of supplying screen to the section is approximately 

$0.10/ft. 

The total cost for installing screen is therefore approximately 

$2.43/ft or $0.58/ton. If screen is installed in 50% of the drivage, 

the cost per ton for the mine drops to $0.29/ton. If this one-section 

mine produces one million tons annually, the yearly cost for the 

screen installation is $240,000. A single rock fall injury could cost 
 

 

 

 

 

 

 

 

more than that amount. Indeed, if the screen program succeeds in 

reducing workman’s compensation premiums by just 25% at this 

mine, the savings could be sufficient to pay for the entire program. 

In fact, the economic benefits of roof screening go well beyond 

a reduction in direct injury costs. An effective screening program 

that brings down the rate of rock fall injuries can also save money 

by: 

•	 Reducing the costs associated with replacing injured 

workers, 

•	 Reducing labor turnover and improving workforce morale, 

•	 Reducing requirements for extra spot bolts to support loose 

roof, and, 

•	 Reducing the costs associated with long-term clean-up and 

re-support. 

CONCLUSIONS 

Roof screen has the potential to prevent hundreds of injuries 

caused by the fall of small rocks between permanent roof supports. 

The ability of screen to cover all of the gaps between permanent 

supports makes it by far the most effective method for stopping the 

fall of these relatively small rocks. Simple modifications and 

installation procedures can substantially increase the efficiency of 

outside controlled dual boom roof bolting machines used to install 

roof screen. Supplying roof screen to racks/rails fitted on bolters or 

at least leaning screen against the rib instead of leaving it on the 

ground can significantly reduce the risk of a back or strain injury to 

roof bolter operators. Material handling systems that are available 

now on J. H. Fletcher & Co. roof bolters can greatly reduce the 

stress and strains associated with roof screen installation as well as 

reduce the time necessary to complete screen installation. Basic 

machine modifications, well planned supply methods, and using 

best practice installation techniques can minimize the economic 

effects of roof screen installation on a mine’s overall mining cycle. 

Reducing the number of rock fall injuries at a mine will also have a 

very positive effect on the economics of a mine and it can improve 

the morale of the entire workforce. 

REFERENCES 

Gadde, M., Rusnack, J. and Honse, J. (2006). Behavior of Welded 

Wire Mesh Used for Skin Control in Underground Coal Mines. 

Proceedings of the 25th International Conference on Ground 

Control in Mining, Morgantown, WV, August 1-3, pp. 142-151. 

Kotowski, S., Gallagher, S. R, Davis, K., Baron, K. and 

Compton, C. (2006). Musculoskeletal Stress on Miners Performing 

Roof Screening Operations. Proceedings of the Human Factors and 

Ergonomics Society 50th Annual Meeting, San Francisco, CA, Oct. 

16-20, pp. 1370-1374. 

Molinda, G., Robertson, S., Mark, C., and Dolinar, D. (2003). 

Covering the Roof Reduces Crippling Injuries Underground. Coal 

Age, November/December, pp. 20-26. 

MSHA (2007). Accident, illness and injury and employment selfextracting files (part 50 data), 2001-2006. Denver, CO: U.S. 

Department of Labor, Mine Safety and Health Administration, 

Office of Injury and Employment Information. 

[http:/www.msha.gov/STATS/PART50/p50y2k/ p50y2k.HTM] 

Feb. 2007. 

Robertson, S., Molinda, G., Dolinar, D., Pappas, D. and 

Hinshaw, G. (2003). Best Practices and Bolting Machine 

Innovations for Roof Screening. SME Preprint No. 03-158; pp.1-8.