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IC 
 
 8997 
 
 Bureau of Mines Information Circular/1985 
 
 Automated Temporary Roof Support 
 (ATRS) Systems for Roof 
 Bolting Machines 
 
 Proceedings: Bureau of Mines Technology Transfer 
 Symposium, Charleston, WV, June 23, 1983 
 
 Compiled by William W. Aljoe 
 
 UNITED STATES DEPARTMENT OF THE INTERIOR g» 
 
 c 
 
 75 
 
 Af/NES 75TH A^ 
 
Information Circular 8997 ( . 
 
 Automated Temporary Roof Support 
 (ATRS) Systems for Roof 
 Bolting Machines 
 
 Proceedings: Bureau of Mines Technology Transfer 
 Symposium, Charleston, WV, June 23, 1983 
 
 Compiled by William W. Aljoe 
 
 UNITED STATES DEPARTMENT OF THE INTERIOR 
 William P. Clark, Secretary 
 
 BUREAU OF MINES 
 Robert C. Horton, Director 
 
«D 
 
 W 
 
 O 
 
 Q' 
 
 Library of Congress Cataloging in Publication Data: 
 
 Bureau of Mines Technology Transfer Symposium (1983: 
 Charleston, WV) 
 
 Automated temporary roof support (ATRS) systems for roof boltinj 
 machines. 
 
 (Information circular ; 8997) 
 
 Includes bibliographical references. 
 
 Supt. of Docs, no.: I 28.27:8997. 
 
 1. Mine roof bolting— Automation. 2. Mining machinery —Automa- 
 tion. I. Aljoe, William W. II. Title. III. Series: Information circu- 
 lar (United States. Bureau of Mines) ; 8997. 
 
 m29&,«4 [TN289.3] 622s [622'.2] 84-600208 
 
CONTENTS 
 
 Page 
 
 Abstract 1 
 
 Improved roof control safety with ATRS systems, by M. Terry Hoch and William J. 
 
 Debevec. 2 
 
 Development of waiver guidelines for the use of ATRS systems in West Virginia 
 
 coal mines, by Govindappa Puttaiah and Ashok K. Agrawal 9 
 
 Field test of an ATRS system on a low-coal, single fixed-head roof bolting 
 
 machine (squirmer), by Edward A. Barrett and Thomas E. Marshall 18 
 
 Development of an ATRS system for Fairchild Inc. roof drills, by George Cobb... 27 
 
 Retrofit ATRS systems for roof bolters, by Gary 0. Bledsoe 32 
 
 The Schroeder Frontrunner roof bolter with ATRS system, by Gus Schroeder 39 
 
 Remotely actuated temporary support (RATS) for FMC underground mining 
 
 equipment , by Martin D. Wotring 48 
 
 Roof support systems for Fletcher roof drills, by Douglas R. Hardman . ... 55 
 
 ATRS systems for Lee-Norse roof bolters , by Guido Bucelluni 69 
 
 Long-Airdox ATRS systems for roof bolters, by C. L. Bandy, Jr., and David L. 
 
 Phillips 74 
 

 UNIT OF 
 
 MEASURE 
 
 ABBREVIATIONS USED 
 
 IN 
 
 THIS REPORT 
 
 ft 
 
 foot 
 
 
 lb/ft 2 
 
 
 pound per square foot 
 
 f t/min 
 
 foot per 
 
 minute 
 
 pet 
 
 
 percent 
 
 gal 
 
 gallon 
 
 
 psi 
 
 
 pound per square inch 
 
 in 
 
 inch 
 
 
 s 
 
 
 second 
 
 lb 
 
 pound 
 
 
 yr 
 
 
 year 
 
AUTOMATED TEMPORARY ROOF SUPPORT (ATRS) SYSTEMS 
 FOR ROOF BOLTING MACHINES 
 
 Proceedings: Bureau of Mines Technology Transfer Symposium, 
 Charleston, WV, June 23, 1983 
 
 Compiled by William W. Aljoe 1 
 
 ABSTRACT 
 
 This publication contains 10 papers presented at a symposium on ATRS 
 systems in Charleston, WV, on June 23, 1983. Included are papers by 
 MSHA Technical Support (Roof Control) , West Virginia Institute of Tech- 
 nology, the Bureau of Mines, and seven roof bolter manufacturers and/or 
 designers of ATRS systems. These papers summarize the most recent de- 
 velopments in ATRS technology and can serve as a guide to potential de- 
 signers, developers, and users of ATRS systems. 
 
 1 Mining engineer, Pittsburgh Research Center, Bureau of Mines, Pittsburgh, PA, 
 
IMPROVED ROOF CONTROL SAFETY WITH ATRS SYSTEMS 
 By M. Terry Hoch 1 and William J. Debevec 2 
 
 The collapse of mine roof has always 
 been a major safety problem confronting 
 the mining industry. Historically, roof 
 falls have caused the death of more coal 
 miners than the combined total of all 
 other types of accidents. From 1906 
 through 1980, 85,026 lives were claimed 
 in coal mine underground workings. Roof 
 falls were responsible for 44,628 of 
 these deaths, or 52 pet of the fatalities 
 on record. However, as can be seen in 
 figure 1, roof fall fatalities have ex- 
 hibited a downward trend. This graph was 
 formulated by taking 10-yr increments 
 
 1 
 
 Supervisory mining engineer. 
 
 ^Mine safety specialist. 
 Bruceton Safety Technology Center, 
 Mine Safety and Health Administration, 
 Bruceton, PA. 
 
 from 1910-19 through 1970-79, averaging 
 the roof fall fatalities occurring in 
 those years, and plotting them chronolog- 
 ically. Although the number of miners 
 working in underground bituminous mines, 
 and therefore the number of hours worked, 
 has decreased in these years , the per- 
 centage reduction in workers and worker- 
 hours is far less than the percentage re- 
 duction in roof fall fatalities. 
 
 Accident statistics are often deceiv- 
 ing unless normalized with exposure 
 times. The following material is in- 
 tended to place accident information into 
 perspective. Figure 2 compares the tons 
 mined, the worker-hours involved, and the 
 roof fall fatalities for 1970 through 
 1982. All of these statistics were re- 
 ceived from the Mine Safety and Health 
 
 1,350 
 
 ,200 - 
 
 (/> 
 
 1,05 
 
 UJ 
 
 
 K 
 
 
 IJ 
 
 900 
 
 < 
 
 
 r- 
 
 
 < 
 u_ 
 
 750 
 
 -J 600 1- 
 < 
 
 o 450 
 o 
 
 300 
 150 [ 
 
 
 1910-19 1920-29 1930-39 1940-49 1950-59 1960-69. 1970-79 
 FIGURE 1. - Roof fall fatalities - 10-yr average. 
 
100 
 
 240 
 
 H 220 £ 
 
 3 
 o 
 
 ■ 200 « 
 
 o 
 180 ^ 
 
 Ld 
 
 1970 1972 1974 1976 1978 1980 1982 
 
 FIGURE 2. - Frequency curves. 
 
 350 
 
 325 g 
 
 300 
 
 CD 
 O 
 
 275 o 
 
 Q 
 O 
 
 rr 
 250 cl 
 
 225 
 
 Administration (MSHA) Health and Safety 
 Analysis Center (HSAC) in Denver, CO, and 
 pertain only to underground bituminous 
 coal mines. A high of 84 fatalities was 
 registered in 1970 and a low of 31 in 
 1980. The 1970 high of 337.9 million 
 tons has not been surpassed, although the 
 1982 total of 320.9 million tons repre- 
 sents the second highest mark in this 13- 
 yr study. The drastic decrease in ton- 
 nage for 1977 and 1978 was due to work 
 stoppages. (Note that the baseline of 
 the graph represents 225 million tons.) 
 Worker-hours have followed a definite up- 
 ward trend with a leveling off in the 
 past few years. Since 1970, an increase 
 of approximately 40 pet in total worker- 
 hours can be seen. With the increase in 
 
 hours worked and the general decrease in 
 roof fall fatalities over the past 13 yr, 
 a correlation exists suggesting that sig- 
 nificant safety advances have been made 
 that protect miners from the No. 1 under- 
 ground hazard - roof falls. 
 
 This paper discusses one of these ad- 
 vances that MSHA believes to be a major 
 contributor to this reduction in roof 
 fall fatalities and that has a tremendous 
 potential for further decreasing fatali- 
 ties and injuries in the years to come. 
 This advance is the use of automated tem- 
 porary roof support (ATRS) systems, which 
 provide protection from roof falls and 
 are remotely set from beneath permanently 
 supported roof. 
 
 1979-81 ROOF FALL FATALITIES: GENERAL OBSERVATIONS 
 
 As a means of justifying our be- 
 liefs, let us first take a close look 
 at the roof fall fatality records for 
 1979, 1980, and 1981. The reason for 
 focusing on these years is because a suf- 
 ficient description of the statistics is 
 available and the use of ATRS systems 
 was beginning to accelerate during these 
 years. It is estimated that machines 
 equipped with ATRS systems increased from 
 
 approximately 1,500 in 1979 to approxi- 
 mately 2,500 by June 1, 1983. 
 
 Table 1 summarizes the roof fall fatal- 
 ities that occurred in 1979, 1980, and 
 1981. The total number of fatalities for 
 all types of accidents in underground bi- 
 tuminous mines respectively was 105, 94, 
 and 112, and the total number of roof 
 fall fatalities in these years was 65, 
 
TABLE 1. - Summary of roof fall 
 fatalities 1 
 
 Fatalities 
 
 Underground bituminous 
 
 (total) , 
 
 Roof fall , 
 
 Roof fall (inby 
 
 supports) , 
 
 Percent of roof fall 
 
 fatalities (inby 
 
 supports) 
 
 'HSAC statistics. 
 
 1979 
 
 105 
 65 
 
 52 
 
 80 
 
 1980 
 
 94 
 32 
 
 22 
 
 69 
 
 1981 
 
 112 
 41 
 
 24 
 
 59 
 
 fall fatalities that are directly asso- 
 ciated with manual setting of temporary 
 supports. This activity is listed as 
 "setting, removing, or preparing posts" 
 by HSAC. With an ATRS system, this ac- 
 tivity would virtually be eliminated and 
 would reduce the amount of exposure time 
 in which miners would be inby supports. 
 As the figures show in table 2, the per- 
 centage of fatals related to manually set 
 temporary supports compared with total 
 roof fall fatals in any year has been 
 decreasing. 
 
 32, and 41. A breakdown of these roof 
 fall fatalities was made by HSAC, and it 
 revealed that a large percentage has oc- 
 curred inby permanent supports. Table 1 
 illustrates that in 1979, 1980, and 1981 
 there were respectively 52, 22, and 24 
 roof fall fatalities inby supports. Al- 
 though this number is unacceptably high, 
 the percentage of roof fall fatalities 
 that have occurred inby supports with re- 
 spect to total roof fatals has progres- 
 sively decreased in this 3-yr period. 
 These figures imply that ATRS systems are 
 reducing the percentage of roof fall fa- 
 talities occurring inby supports. Also, 
 significant reductions in the total num- 
 ber of fatalities can be assumed as more 
 and more mines convert to ATRS systems 
 from manually set temporary supports. 
 
 Additional statistics that justify this 
 belief are expressed in table 2. This 
 figure illustrates the number of roof 
 
 TABLE 2. - Fatality data on manually 
 set temporary supports 
 
 Fatalities 
 
 1979 
 
 1980 
 
 1981 
 
 Setting, removing, or 
 
 
 
 
 
 20 
 
 7 
 
 8 
 
 
 65 
 
 32 
 
 41 
 
 
 31 
 
 22 
 
 20 
 
 The point to be brought out by these 
 statistics is that no matter what year 
 is viewed, the results are the same; the 
 occupations that require men to work 
 in close proximity to the unsupported 
 face are the high-fatality-frequency 
 jobs. Assuming that the miners were well 
 trained in roof control techniques, it 
 can be implied that a reduction in acci- 
 dents can be achieved by technological 
 advances and by reducing or eliminating 
 the amount of exposure time spent in un- 
 supported areas through the use of auto- 
 mated temporary roof support. 
 
 ATRS IN LIEU OF CANOPIES 
 
 The ATRS systems presently in use are 
 an integral part of the roof bolting ma- 
 chines or continuous miners equipped with 
 integral bolters. They are designed so 
 they can be set in the unsupported area 
 from a remote position under permanent 
 support. As the name implies, they are 
 automated and therefore provide a posi- 
 tive support to the mine roof and elimi- 
 nate the human error involved in setting 
 conventional temporary support. 
 
 MSHA, through the Roof Control Division 
 of the Bruceton Safety Technology Cen- 
 ter in cooperation with our enforcement 
 
 personnel, has pioneered the development 
 of ATRS systems for the past 10 yr. 
 Working with mining companies, machine 
 manufacturers, union representatives, 
 State agencies, and independent jobbers 
 has produced safe, functional designs. 
 In fact, the design of ATRS systems has 
 been perfected so that in many mines they 
 are accepted in lieu of canopies over the 
 drilling controls of roof bolters and 
 continuous miners with integral bolters. 
 To be approved for use in lieu of cano- 
 pies, the system must provide equal or 
 greater protection from roof falls to the 
 operator as required in CFR 75. 1710-l(f ) . 
 
The first "in-lieu-of" approval was 
 granted in 1976, and since then 191 ap- 
 provals have been issued. They involve 
 301 mines and approximately 2,000 ma- 
 chines. An additional 500 machines in 
 the field have an ATRS with a canopy, 
 which precludes the necessity for an 
 "in-lieu-of" approval. Experience with 
 machines currently equipped with ATRS 
 systems shows that mine operators are 
 realizing a substantial reduction in ac- 
 cidents caused by falls of mine roof dur- 
 ing the roof bolting cycle. In addition, 
 the use of these systems has resulted in 
 the reduction of both face bolting time 
 and the manual workload for roof bolter 
 operators and helpers. 
 
 Currently, there is some confusion be- 
 tween approval of an ATRS system to re- 
 place manual setting of temporary sup- 
 ports and approval for use in lieu of 
 canopies. Figure 3 illustrates the dif- 
 ference. For a mining company to gain 
 approval to use an ATRS system to re- 
 place manual setting of temporary sup- 
 ports, the company must submit an appli- 
 cation through the local MSHA district 
 manager. Acceptance is conditional, de- 
 pending on a variety of mining circum- 
 stances. On the other hand, if the ma- 
 chine does not provide a substantial 
 canopy, the ATRS system may be accepted 
 for use in lieu of a canopy over the 
 drilling controls, but approval must be 
 granted by the Chief of MSHA's Bruceton 
 Safety Technology Center, through the 
 Director of Technical Support. 
 
 Based on past performance and in-mine 
 investigations, the following general 
 criteria have been established to deter- 
 mine the acceptability of ATRS systems 
 for either approval: 
 
 Approvals 
 
 ATRS 
 
 To replace manually 
 
 setting temporary 
 
 supports 
 
 ATRS 
 
 Acceptance for use 
 in lieu of 
 a canopy 
 
 MSHA 
 district manager 
 
 ' MSHA v 
 
 technical support 
 chief of safety center 
 
 FIGURE 3. - Approvals. 
 
 1. The necessary ATRS system controls 
 should be located so that they can be op- 
 erated from under permanent supports. 
 
 2. The ATRS system should be firmly 
 placed against the roof before advancing 
 inby permanent supports. 
 
 3. All ATRS system hydraulic jacks 
 should have check valves. 
 
 4. The ATRS system should be certified 
 by a registered, professional engineer to 
 withstand a prescribed load. This load 
 is dependent on the intended work area. 
 
 5. The distance between the ATRS sys- 
 tem and the coal face, rib, or perma- 
 nent or temporary supports should be not 
 greater than 5 ft. 
 
 6. Inch tram speed should be limited 
 to a maximum of 80 ft/min. 
 
 GENERAL DESCRIPTION OF ATRS TYPES 
 
 Current ATRS systems consist of either 
 a bar-type or safety-arm-type support for 
 roof bolting machines and hydraulic jacks 
 equipped with roof contact pads for con- 
 tinuous miners with integral bolters. 
 Each has advantages and disadvantages de- 
 pending on the specific application, but 
 
 in general, they all perform the basic 
 function of providing temporary support 
 while the roof is being bolted. 
 
 Shown in figure 4 is a side view of the 
 safety-arm type. It was developed to 
 provide temporary roof support in the 
 
immediate area of the roof bolt being in- 
 stalled. This type consists of a pair of 
 steel arms mounted on each drill boom 
 with a support structure attached to the 
 
 FIGURE 4. - Safety-arm-type ATRS system. 
 
 top end. The support structures, which 
 are of various sizes and configurations, 
 are pressurized against the mine roof 
 from a remote position by means of hy- 
 draulic elevating cylinders that rest 
 directly on the mine floor. With the 
 safety-arm type, the ATRS system must be 
 repositioned remotely for each bolt to be 
 installed. 
 
 Figure 5 displays a single-bar system. 
 The bar-type ATRS usually consists of ei- 
 ther one or two bars equipped with roof 
 contact pads mounted atop a hydraulic 
 jack that can be pressurized against the 
 mine roof from under permanently sup- 
 ported roof. This system is generally 
 attached to a dual-boom roof bolter. 
 
 Dual-boom roof bolting machines are 
 generally easier to equip with an ATRS 
 system than single-boom, fixed-head 
 "squirmer-type" machines. The lack of an 
 operator's compartment and the location 
 of the drilling controls at the front 
 
 KEY 
 ■ Roof bolt 
 x Proposed bolt hole 
 
 O Operator's position 
 X X 
 
 i i 
 i i 
 
 V 
 
 I 
 
 r'-S 
 
 I I 
 1 I 
 
 7 
 
 Inch tram -ATRS 
 
 Tram station 
 
 FIGURE 5. - Single-bar ATRS system. 
 
of the single-head machines account for 
 the difficulty. Although some operators 
 have been successful in placing canopies 
 over a newly attached operator's compart- 
 ment, in many cases this hinders the 
 roof bolting operations because the can- 
 opy restricts roof bolting close to the 
 rib. Therefore, several mine operators 
 equipped their roof bolters with ATRS 
 systems for use in lieu of canopies over 
 the drilling controls. Figure 6 is a 
 plan view drawing of a fixed-head machine 
 with an ATRS. The systems are generally 
 modified versions of types adapted to the 
 dual-boom roof bolting machines, and some 
 have been approved in lieu of canopies 
 and as sole or partial means of temporary 
 support during the roof bolting cycle. 
 
 Although ATRS systems on single-boom 
 bolters for use in lieu of canopies have 
 been accepted by MSHA on a mine-to-mine 
 basis, their use as the sole means of 
 temporary support has been limited. The 
 inherent design of the machine requires 
 it to be repositioned after each bolt 
 
 ,Dnlling controls 
 
 ATRS 
 tram controls 
 
 I Hi 
 
 -inch / 
 
 KEY 
 ■ Roof bolt 
 x Proposed bolt hole 
 OOperator's position 
 
 FIGURE 6. - Fixed-head machine with ATRS. 
 
 installation. However, improved technol- 
 ogy, actual underground work experience, 
 design modifications, and changing of 
 work procedures have resulted in an 
 increase in the use of these ATRS systems 
 as temporary support. 
 
 Approvals of ATRS systems on continuous 
 miners has been increasing in the past 
 few years. By law, canopies are required 
 over the drilling controls on continuous 
 miners equipped with integral drills. 
 However, in many cases these canopies ex- 
 tend beyond the machine frame and require 
 greater mining widths to accommodate 
 them. These wider entries were detrimen- 
 tal to good roof control; therefore, in 
 some mines operators have equipped their 
 machines with ATRS systems which can be 
 accepted in lieu of canopies over the 
 drilling controls. Figure 7 shows a plan 
 view of a continuous miner with ATRS 
 jacks. The sequence of operation is as 
 follows: 
 
 1. The roof bolt operators remain un- 
 der permanent support until mining has 
 progressed far enough to install the next 
 row of bolts. 
 
 2. The miner operator then positions 
 the ATRS supports firmly against the 
 roof. 
 
 3. The bolter operators then advance 
 to their drilling controls and install 
 the roof bolts. 
 
 4. When the bolting is completed, the 
 roof bolter operators retreat to a perma- 
 nently supported area and the mining cy- 
 cle continues. 
 
 It is easy to see that safety and pro- 
 duction can be enhanced with the use of 
 ATRS systems on continuous miners by roof 
 bolting close to the face and reducing 
 the number of moves required. 
 
Front ATRS pads Front ATRS controls 
 .(set by miner operator)/ 
 
 ^Miner controls 
 
 Operator's 
 canopy 
 
 Rear ATRS pads 
 (set by bolter) 
 
 Drilling-rear 
 ATRS controls 
 
 Roof bolts' 
 
 FIGURE 7. - Continuous miner with ATRS jacks. 
 
 CONCLUSION 
 
 A review of fatality statistics shows 
 a general downward trend, particularly 
 in the roof control area. MSHA believes 
 that a major contributor to this re- 
 duction has been the use of ATRS sys- 
 tems on roof bolters and continuous 
 miners equipped with integral bolters. 
 The Roof Control Division of MSHA and our 
 
 enforcement personnel have assisted and 
 will continue to assist manufacturers and 
 mining companies in the development of 
 workable ATRS systems. The outlook is 
 very bright for even further reduction 
 in accidents and fatalities through the 
 use of automated temporary roof support 
 systems. 
 
DEVELOPMENT OF WAIVER GUIDELINES FOR THE USE OF ATRS SYSTEMS 
 IN WEST VIRGINIA COAL MINES 
 
 By Govindappa Puttaiah 1 and Ashok K. Agrawal 
 
 INTRODUCTION 
 
 More than 35,000 miners have been 
 killed by roof falls in underground coal 
 mines in the past 70 yr. As shown in 
 figure 1, the yearly toll has been dra- 
 matically reduced during the last few 
 decades due to improved mining methods. 
 However, the fatality figures are still 
 unacceptably high, and further reduction 
 could be achieved with better roof sup- 
 port techniques. 
 
 Table 1 shows that roof falls have his- 
 torically accounted for approximately 50 
 pet of all underground coal mine fatali- 
 ties each year (^). 2 Studies have also 
 shown that 60 pet of the roof fall fatal- 
 ities occur within 25 ft of the face. Of 
 
 the 211 roof fall fatalities between 1974 
 and 1978, 109 occurred inby permanent 
 supports and 46 involved miners who were 
 manually setting or removing temporary 
 posts or jacks. 
 
 Current mining practice requires that 
 prior to installing permanent roof sup- 
 ports, miners must enter unsupported roof 
 areas to manually set temporary supports. 
 Such temporary supports provide protec- 
 tion during the bolt installation cycle. 
 To minimize worker exposure to the unsup- 
 ported roof , various Federal agencies , 
 mining machinery manufacturers, and min- 
 ing companies initiated the development 
 of automated roof support (ATRS) systems. 
 
 1 Division of Mining Engineering Tech- 
 nology, West Virginia Institute of Tech- 
 nology, Montgomery, WV. 
 
 ^underlined numbers in parentheses re- 
 fer to items in the list of references at 
 the end of this report. 
 
 m 
 
 of" 
 
 < 
 
 Ll) 
 
 >- 
 
 (T 
 UJ 
 Q. 
 
 (/) 
 
 UJ 
 
 2 
 < 
 
 u. 
 
 1,000 
 
 800 - 
 
 600 - 
 
 400 - 
 
 200 - 
 
 V- O) 
 
 C\/ <V f*) "O V \f (O <0 (O (O \ \ 
 
 o m o <o o <o o <o O ,<o p ,<o o {o 
 
 0)0)0) 0)0)0)0) O) O) O) O) O) O) O) 
 
 FIGURE 1. - Coal mine fatalities per year 
 (1910-79). 
 
 TABLE 1. - Total fatality-roof fall 
 fatality record of West Virginia 
 coal mines (1960-79) 
 
 Year 
 
 Total 
 
 Roof fall 
 
 pet 1 
 
 
 fatalities 
 
 fatalities 
 
 
 
 115 
 
 66 
 
 57.4 
 
 
 84 
 
 41 
 
 48.8 
 
 
 77 
 
 39 
 
 50.6 
 
 
 126 
 
 55 
 
 43.6 
 
 
 85 
 
 48 
 
 56.4 
 
 
 93 
 
 53 
 
 57.0 
 
 
 81 
 
 40 
 
 49.4 
 
 
 60 
 
 28 
 
 46.6 
 
 
 152 
 
 30 
 
 19.7 
 
 
 69 
 
 27 
 
 39.1 
 
 
 63 
 
 29 
 
 46.0 
 
 
 41 
 
 16 
 
 39.0 
 
 
 48 
 
 13 
 
 27.1 
 
 
 41 
 
 19 
 
 46.3 
 
 
 36 
 
 16 
 
 44.4 
 
 
 34 
 
 12 
 
 35.3 
 
 
 32 
 
 7 
 
 21.9 
 
 1977 
 
 28 
 
 13 
 
 46.4 
 
 1978 
 
 29 
 
 11 
 
 38.0 
 
 
 35 
 
 16 
 
 45.7 
 
 1 Roof fall fatalities 
 tal fatalities. 
 
 as percent of to- 
 
10 
 
 These systems can provide protection dur- 
 ing the bolting cycle by remotely setting 
 the temporary support. Over the past 
 decade or so, considerable progress has 
 been made in the development of various 
 types of ATRS systems. Use of ATRS sys- 
 tems in underground coal mines started to 
 accelerate during the late 1970' s. Cur- 
 rently, many mines are using ATRS systems 
 on dual-boom roof bolters with great suc- 
 cess; however, use of ATRS systems on 
 single-boom bolters is rather limited. 
 Studies of roof fall fatalities for 1979 
 and 1980 have shown that there were 18 
 fewer deaths inby permanent roof support 
 in 1980 than in 1979. This may have been 
 due in part to the increase in ATRS use 
 during 1980. 
 
 create a condition which will cause 
 a greater hazard, to people working 
 inby the area where permanent sup- 
 ports have been installed, than the 
 method presently being employed or 
 proposed by the operator for tem- 
 porarily supporting the roof; or 
 where the technology of an auto- 
 mated temporary roof support system 
 does not exist to allow compliance 
 with the requirements set forth in 
 Section 5.03 of these rules and 
 regulations. In granting a waiver 
 as to the use of the automated tem- 
 porary roof support system, the Di- 
 rector may approve the use of tem- 
 porary jacks and posts to be used 
 in lieu thereof. 
 
 Convinced of the potential danger due 
 to exposure to unsupported roof and the 
 advantages of using ATRS systems , the 
 six-member Coal Mine Health and Safety 
 Board of the West Virginia Department of 
 Mines unanimously approved rules and reg- 
 ulations governing the use of ATRS in 
 West Virginia coal mines. The rules and 
 regulations (chapter 22, article 2-A, 
 section A, series 21 (1981) of the West 
 Virginia Code) became effective on March 
 1, 1981. The regulations state in part — 
 
 5.01 (a) Twelve (12) months after the 
 effective date of these rules and 
 regulations all new and rebuilt, 
 roof bolting machines and continu- 
 ous mining machines with integral 
 roof drills used in a working place 
 in a coal mine shall be provided 
 with an approved automated tempo- 
 rary roof support system: Pro- 
 vided, that other methods of tempo- 
 rarily supporting the roof may be 
 approved by the Director in the 
 adopted approved roof control plan. 
 
 5.02 (b) A waiver may be granted, as to 
 the use of an automated temporary 
 roof support system, by the Direc- 
 tor where it has been demonstrated 
 by the operator and determined dur- 
 ing an investigation by an author- 
 ized representative of the Director 
 that the use of an automated tem- 
 porary roof support system would 
 
 Note that section 5.02 (b) of these 
 rules and regulations states that a 
 waiver may be granted from the use of the 
 ATRS system (1) if it has been demon- 
 strated that its use will cause a greater 
 hazard, or (2) where the technology of an 
 ATRS system does not exist. The above 
 rule also charges the Director of the 
 West Virginia Department of Mines with 
 the responsibility of granting such 
 waivers. In order to grant waivers on an 
 unbiased and technically sound basis, the 
 West Virginia Department of Mines con- 
 tracted the Division of Mining Engineer- 
 ing Technology at West Virginia Institute 
 of Technology to develop and recommend a 
 set of waiver guidelines. Keeping in 
 mind the waiver criteria set forth in the 
 law, the investigators initiated a com- 
 prehensive study of existing ATRS systems 
 and the problems associated with them. 
 The following tasks were performed under 
 the study: 
 
 1. Review of literature on ATRS 
 technology. 
 
 2. Review of MSHA census on roof bolt- 
 ers and ATRS systems in West Virginia. 
 
 3. Visits to ATRS manufacturers and 
 rebuild shops. 
 
 4. Visits to underground coal mines 
 using the ATRS system. 
 
11 
 
 5. Discussions with Federal agen- 
 cies, coal industry groups, and labor 
 associations. 
 
 6. Review of statistical information 
 on roof falls. 
 
 7. Review of geological and engineer- 
 ing literature on the region's coal mine 
 roof strata. 
 
 No attempt is made here to establish 
 rigid guidelines; this would tend to 
 
 oversimplify extremely complex relation- 
 ships that exist among various ATRS- 
 related mining variables. It became evi- 
 dent during the study that the procedures 
 and criteria to be considered in the 
 evaluation of such guidelines must be 
 clarified. Thus, the results of this re- 
 port include a thorough review of the 
 technical status of ATRS systems and the 
 identification of various factors that 
 need to be evaluated in the consideration 
 of an ATRS waiver. 
 
 ROOF BOLTER SURVEY 
 
 Section 5.01 (b) of the ATRS regulation 
 requires that, starting March 1, 1984, 
 all the existing roof bolting machines 
 and continuous mining machines with inte- 
 gral roof drills used in a working place 
 must be retrofitted with an approved ATRS 
 system. Hence, it became necessary that 
 a survey of existing roof bolters be con- 
 ducted to get an idea of the magnitude of 
 retrofitting work involved. 
 
 Table 2 shows the data obtained from a 
 roof bolter survey conducted in District 
 4 of the Mine Safety and Health Admini- 
 stration, which covers mines in southern 
 West Virginia. Data were compiled ac- 
 cording to roof bolter types (dual boom 
 or single boom) , ATRS existence on the 
 roof bolter, and manufacturer. The data 
 show that 275 of the 290 dual-boom roof 
 bolters now in use (95 pet) have some 
 type of ATRS system as an integral part 
 of the machine. However, 605 of the 698 
 single-boom roof bolters (almost 87 pet) 
 
 do not have ATRS systems with the machine 
 and may have to be retrofitted. Almost 
 all the continuous miners with integral 
 roof drills have some type of ATRS sys- 
 tem. As shown in table 2, 400 of the 
 605 single-boom roof bolters without ATRS 
 systems (almost 66 pet) are FMC (Galis) 
 models. Fletcher, Long-Airdox, and Lee- 
 Norse account for the majority (23 pet) 
 of the other single-boom roof bolters 
 without ATRS systems. 
 
 No such data were available from MSHA 
 District 3, which covers mines in north- 
 ern West Virginia. However, interviews 
 with MSHA and the West Virginia Depart- 
 ment of Mines personnel revealed that 
 the use of single-boom bolters in Dis- 
 trict 3 is minimal. Therefore, the ex- 
 tent of retrofitting work required in 
 northern West Virginia should not be as 
 great as that required in southern West 
 Virginia. 
 
 TABLE 2. - Summary of roof bolters in southern West Virginia 
 
 Manufacturer 
 
 Dual boom 
 
 Single boom 
 
 
 With ATRS 
 
 Without ATRS 
 
 With ATRS 
 
 Without ATRS 
 
 ACME 
 
 4 
 
 157 
 
 46 
 
 64 
 
 4 
 
 
 
 
 
 
 3 
 6 
 
 5 
 1 
 
 
 
 
 
 
 6 
 73 
 7 
 4 
 2 
 
 1 
 
 
 17 
 
 
 54 
 
 
 400 
 36 
 
 
 20 
 
 Black Diamond (Wildcat).... 
 
 56 
 
 16 
 
 4 
 
 2 
 
 
 275 
 
 15 
 
 93 
 
 605 
 
12 
 
 ATRS SYSTEMS 
 
 MSHA has defined a temporary roof sup- 
 port system (TRS) as a device that sup- 
 ports a minimum weight of 450 lb/ft 2 
 times the area to be supported. Most 
 ATRS systems are incorporated into roof 
 bolting machines or continuous miners 
 equipped with integral roof bolters. The 
 positioning controls for the ATRS are 
 located so the operator can set the sys- 
 tem while remaining under supported roof. 
 Thus, an ATRS system must be extended and 
 pressurized against the newly exposed 
 roof remotely and is intended to replace 
 manually installed posts and/or jacks as 
 temporary support while the roof is being 
 bolted. 
 
 ATRS FOR ROOF BOLTERS 
 
 Various machine manufacturers and ret- 
 rofitted, coal mining companies, the 
 Bureau of Mines, and MSHA's Roof Control 
 Division of the Bruceton Safety Technol- 
 ogy Center have been working for over 10 
 yr to design and produce safe and func- 
 tional ATRS systems for different types 
 of roof bolters. These intensive efforts 
 have resulted in the development of sev- 
 eral workable ATRS systems. 
 
 All currently available ATRS systems 
 can be broadly categorized as either in- 
 tegral types or satellite types. 
 
 An integral type of ATRS system is one 
 in which the system is rigidly attached 
 to the roof bolting machine. Integral- 
 type ATRS systems are available for most 
 existing dual-boom and some single-boom 
 roof bolting machines. The three most 
 common support mechanisms currently 
 available are the ring type, T-bar type, 
 and H-bar type. 
 
 Figure 2 shows the ring type (also 
 called the safety-arm type) ATRS devel- 
 oped to provide temporary roof support 
 in the immediate area of the roof while 
 the bolt is being installed. This type 
 consists of a roof support structure 
 (ring) mounted above each drill boom. A 
 steel arm, a pair of arms, or hydraulic 
 cylinders usually connect the support 
 
 structure to the machine frame and/or the 
 mine floor. The support structures and 
 steel arms have various sizes and config- 
 urations and are pressurized against the 
 mine roof from a remote position by the 
 hydraulic cylinders. The safety-arm ATRS 
 system must be repositioned remotely be- 
 fore each bolt is installed. 
 
 Figure 3 shows a T-bar system, which 
 usually consists of either one or two 
 
 Drilling 
 control? 
 
 7 
 
 ATRS- inch 
 control 
 
 Tram 
 station 
 
 KEY 
 
 ■ Roof bolt 
 x Proposed bolt hole 
 =0 Operator's position 
 
 FIGURE 2. - Ring-type ATRS system. 
 
 W 
 
 <}- 
 
 1 1 
 
 Front view 
 of rocker pad 
 
 KEY 
 x Proposed bolt hole 
 ■ Roof bolt 
 O Operators position 
 
 Inch tram and J 
 ATRS controls S 
 
 FIGURE 3. - T-bar-type ATRS system. 
 
13 
 
 bars equipped with roof contact pads 
 mounted atop a hydraulic jack that can be 
 pressurized against the mine roof from 
 under the permanently supported roof. 
 This system is generally attached to a 
 dual-boom roof bolter. 
 
 Figure 4 shows an H-bar type of system 
 used predominantly as a retrofit kit for 
 single-boom bolters. The basic support 
 and operating mechanisms are similar to 
 those of the ring or safety-arm types. 
 
 The satellite type of ATRS system is 
 being designed mainly for single-boom 
 roof bolters. The Bureau of Mines and 
 several industry organizations are inde- 
 pendently involved in the development and 
 field testing of satellite-type systems 
 (fig. 5). The system basically consists 
 of a steel beam or steel pads supported 
 by double-acting, telescoping hydraulic 
 
 /Operat^j-n 
 
 f Mo u n t i n g plate 
 
 Set left to right 
 
 ATRS protective envelope 
 
 I /"""111 Drill controls Jr=T- 
 \ Operator ^^ — -~~~ 
 
 Tram canopy 
 
 cylinders. The ATRS is carried from 
 place to place and row to row on the 
 drill head but is not an integral part of 
 the machine. During bolting, the support 
 structure is connected to the machine 
 only by hydraulic lines. A detailed de- 
 scription of this system is available 
 through the Bureau of Mines (2). 
 
 ATRS SYSTEMS FOR CONTINUOUS MINERS 
 
 The ATRS law was written to include 
 both roof bolters and continuous miners 
 with integral roof bolters. Although 
 many roof bolter designs are available, 
 only two companies are currently manufac- 
 turing continuous miners with on-board 
 roof bolters. These machines have hy- 
 draulic roof support jacks mounted adja- 
 cent to the drilling and bolting modules 
 just inby the miner operator's com- 
 partment. The jacks can be operated from 
 a safe distance under permanently sup- 
 ported roof. Since both of these miner- 
 bolters already have ATRS systems, no 
 further discussion of these machines is 
 warranted. 
 
 4th row 
 
 3d row 
 
 Head connects 
 
 to satellite 
 
 TRS for 
 
 positioning 
 
 Tram station 
 
 TRS positioning 
 
 controls 
 
 2d row 
 
 I st row 
 
 Roof bolts 
 
 g \ Operator 
 r position 
 
 FIGURE 4. - H.bar=type ATRS system. 
 
 FIGURE 5. - Satellite-type ATRS system. 
 
14 
 
 NEED FOR ATRS WAIVERS 
 
 As noted earlier, section 5.02 (b) of 
 the Rules and Regulations Governing the 
 Use of ATRS systems provides that the 
 key issues to be considered in seeking 
 and granting a waiver are (1) the deter- 
 mination that an ATRS system would cre- 
 ate a greater hazard than the method 
 presently being employed or proposed by 
 the operator, and (2) lack of technology 
 to allow compliance with the ATRS law. 
 Mine geology obviously influences these 
 considerations . 
 
 HAZARD POSSIBILITIES DUE TO ATRS 
 
 A greater hazard to miners (i.e., 
 roof bolter operator and helpers) may be 
 caused by employing an ATRS for the fol- 
 lowing reasons: 
 
 Reduced Visibility . — The use of ATRS 
 may cause reduced visibility of the roof 
 surfaces and the surrounding space in 
 general, particularly in thin-seam coal 
 mines. The roof bolter operator may have 
 difficulty in locating the bolt holes 
 within the tolerances permitted by the 
 roof control plan. This may result in 
 improperly supported roof with the possi- 
 bility of roof falls and/or citations. 
 
 Roof or Floor Conditions . — Severe un- 
 even roof or floor conditions, especially 
 if they are recurring features in the 
 mine, may result in insufficient or non- 
 uniform contact between ATRS support pads 
 and the roof. Under these conditions the 
 use of conventional post-type temporary 
 supports may provide better contact with 
 the roof and greater safety than an ATRS. 
 
 Induced Pressure . — The upward pressure 
 created on an unsupported roof while the 
 ATRS is being set up may destabilize the 
 roof , especially if the immediate roof 
 rock has low shear strength or is in- 
 tensely fractured. However, since the 
 upward force exerted by an ATRS can be 
 controlled by the bolter manufacturer and 
 the drill operator, this should not be 
 considered a criterion for granting a 
 waiver. 
 
 Mobility Considerations . — Movement of 
 an ATRS, particularly the bar type, in a 
 confined space near the face may cause 
 hazardous conditions such as knocking 
 down temporary posts, initiating rib and 
 roof failures by unintentional contact, 
 physical damage to face ventilation sys- 
 tems , etc. 
 
 LACK OF ATRS TECHNOLOGY 
 
 Roof bolter size and coal seam thick- 
 ness are the two main factors that need 
 to be considered during the evaluation of 
 any ATRS technology. Interviews with the 
 manufacturers and retrofitters have re- 
 vealed that the size of the roof bolter, 
 and not the type, was the major problem 
 in the development of a workable ATRS 
 system. Because a direct relationship 
 exists between the bolter size and coal 
 seam thickness , the presence or lack of 
 ATRS technology depends on coal seam 
 thickness. In this report, a thin seam 
 is defined as one that is less than 36 
 in; medium, between 36 and 60 in; thick, 
 between 60 and 100 in; and very thick, 
 over 100 in. 
 
 In general, there are few ATRS systems 
 available for thin coal seams. However, 
 discussions with manufacturers of roof 
 bolters indicate that efforts are being 
 made to develop ATRS systems for low 
 coal, primarily for new roof bolters. 
 However, as shown in table 2, a large 
 number of existing single-boom roof bolt- 
 ers must be retrofitted with ATRS by 
 March 1, 1984. Since most of the re- 
 quests for ATRS waivers will be for thin- 
 seam roof bolters, careful examination 
 must be made of the available retrofit 
 technology. 
 
 Some large manufacturers are developing 
 retrofit ATRS systems for their existing 
 thin-seam roof bolters. Several designs 
 are beyond the prototype stage, and oth- 
 ers are on the drawing board. These de- 
 signs are expected to be available before 
 1984 and should be able to meet the needs 
 of most existing thin-seam roof bolters. 
 
15 
 
 A wide variety of ATRS systems are now 
 available for roof bolters used in medium 
 seams. Therefore, no waivers should be 
 granted to medium-seam roof bolters based 
 on seam thickness alone. 
 
 Sufficient ATRS technology also exists 
 for thick-seam roof bolters; therefore, 
 no waivers should be granted. Although 
 ATRS technology for very thick coal seams 
 (above 100 in) is not as well devel- 
 oped as it is for medium and thick seams , 
 very thick seam mines are not common in 
 West Virginia. Therefore, requests for 
 
 waivers in very thick seams can easily be 
 treated on an individual basis. 
 
 MINE GEOLOGY 
 
 The frequency of roof falls is closely 
 related to immediate roof conditions (ta- 
 bles 3 and 4, figure 6) (3). As shown in 
 table 3, shale was the immediate roof 
 rock in over 80 pet of roof falls where 
 fatalities occurred. Table 4 shows that 
 thickness of the shale roof has a signif- 
 icant impact on roof stability; as shale 
 
 TABLE 3. - Roof conditions where fatalities occurred 
 
 Rock type 
 
 Good to 
 firm 
 
 Fair 
 
 Poor 
 
 Bad 
 
 Total 
 cases 
 
 pet 
 
 Shale 
 
 8 
 5 
 
 
 
 46 
 2 
 
 6 
 
 140 
 
 10 
 
 
 
 23 
 
 22 
 2 
 1 
 4 
 
 216 
 
 19 
 
 1 
 
 33 
 
 80.29 
 
 Head or top coal 
 
 7.06 
 
 .38 
 
 12.27 
 
 
 13 
 
 54 
 
 173 
 
 29 
 
 269 
 
 100.00 
 
 TABLE 4. - Comparison of roof fall data by period 
 
 
 July 1973-June 1978 
 
 July 1978-June 1980 
 
 
 Mine 
 acres 
 
 Roof 
 falls 
 
 Falls per 
 acre 
 
 Mine 
 acres 
 
 Roof 
 falls 
 
 Falls per 
 acre 
 
 Reduction 
 in F/A, ' pet 
 
 Shale roof thick- 
 ness, ft: 
 
 to 5 
 
 118.2 
 111.8 
 76.2 
 53.9 
 30.1 
 13.5 
 
 30 
 56 
 49 
 71 
 50 
 37 
 
 0.16 
 .50 
 .64 
 1.32 
 1.66 
 2.74 
 
 246.0 
 71.5 
 31.8 
 56.0 
 18.6 
 29.8 
 
 10 
 17 
 
 9 
 11 
 
 
 11 
 
 0.04 
 .24 
 .28 
 .20 
 .0 
 .37 
 
 75 
 
 >5 to 10 
 
 52 
 
 >10 to 20 
 
 56 
 
 >20 to 30 
 
 85 
 
 >30 to 40 
 
 100 
 
 
 86 
 
 Total or average 
 Extraction ratio (e): 
 
 473.7 
 
 91.2 
 
 382.5 
 
 77.3 
 
 32.7 
 
 363.7 
 
 293 
 
 84 
 
 209 
 
 9 
 
 5 
 
 279 
 
 .62 
 .92 
 .55 
 
 .12 
 .15 
 .77 
 
 453.7 
 
 19.5 
 
 434.2 
 
 242.7 
 
 174.2 
 
 36.8 
 
 58 
 
 8 
 
 50 
 
 12 
 34 
 12 
 
 .13 
 .41 
 .12 
 
 .05 
 .19 
 .33 
 
 80 
 55 
 79 
 
 58 
 
 227 
 
 57 
 
 ' Falls per acre of mine development. 
 
 2 This apparent increase in falls per acre i 
 being too low (5 falls was an incomplete sampl 
 been 0.45, or midway between 0.12 and 0.77. 
 represent an equivalent 57 pet reduction over 
 
 s probably a result of the 0.15 figure 
 e) . A more realistic figure would have 
 Then the 0.19 figure for 1978-80 would 
 the first period. 
 
16 
 
 roof thickness increased from 5 to 20 ft, 
 roof falls per acre increased from 0.16 
 to 0.64. 
 
 Local defects such as slickensides , 
 pots, slips, loose shale, fractures, and 
 faults are associated with a majority of 
 roof falls and fatalities (fig. 6). Fur- 
 thermore, roof rock properties, especial- 
 ly those of shale, are affected by chang- 
 ing moisture conditions in the mine. 
 Therefore, a thorough evaluation of imme- 
 diate roof geology and the mine moisture 
 conditions should be made as part of any 
 waiver consideration. 
 
 Slickensides, pots, slips 
 Loose shale or slate 
 Fractures 
 Moisture 
 
 Faults 
 
 Disturbance, bumps 
 Separations in roof 
 
 20 40 60 
 FATAL ACCIDENTS, pet 
 
 FIGURE 6. - Geological conditions contributing 
 to fatal roof falls. 
 
 RECOMMENDATIONS 
 
 1. The West Virginia Department of 
 Mines should define more precisely what a 
 waiver is likely to encompass. Opinions 
 of manufacturers, operators, safety and 
 training directors, and miners show no 
 consensus whatsoever on the extent of an 
 ATRS waiver. Some believe that a mine- 
 wide waiver may be necessary, while oth- 
 ers think that it may be needed for only 
 a part of the mine. Still others feel 
 that a waiver may be necessary only for a 
 particular machine. This confusion as to 
 the intent and applicability of the ATRS 
 waiver should be resolved before consid- 
 ering any waiver request. 
 
 2. The Department of Mines should de- 
 fine the term "Waiver" more precisely in 
 order to make the distinction between a 
 "waiver" and a modification to the exist- 
 ing mine roof control plan. Many mines 
 will have to change their present roof 
 control plans to allow incorporation of 
 ATRS systems. 
 
 3. A comprehensive study of all fac- 
 tors discussd in this report should 
 be conducted upon receipt of a waiver 
 application. 
 
 4. All factors should be weighed on 
 their merits and considered together and 
 no single factor should be the deciding 
 criterion, with the possible exception of 
 available ATRS technology. 
 
 5. All roof bolter operators and help- 
 ers not already using ATRS systems should 
 be provided with formal hands-on training 
 in the use of the ATRS system. 
 
 6. The Department of Mines should con- 
 duct a series of seminars on current ATRS 
 technology and waiver granting proce- 
 dures. These seminars should be struc- 
 tured to review the current status of 
 ATRS technology and, most importantly, 
 inform the mining industry of the re- 
 quirements and interpretation of the ATRS 
 law. 
 
 7. The Department of Mines should 
 send a letter of reminder to all under- 
 ground coal mine operators regarding the 
 March 1984 effective date of the ATRS 
 regulations. 
 
 Although nearly all manufacturers have 
 either developed or are actively work- 
 ing on developing ATRS for their roof 
 bolters, and a few are gearing up to 
 meet the expected retrofit demand, this 
 was not the case with the majority 
 of the manufacturers. They seem to be 
 waiting for orders from operators before 
 manufacturing and stocking retrofit 
 kits. We believe that this lack of pre- 
 paredness for the anticipated surge in 
 demand for ATRS kits could create back- 
 log problems as the deadline approaches. 
 However, some larger companies that 
 
own and operate their own rebuild shops 
 are already retrofitting all their roof 
 bolters with ATRS, and some smaller 
 welding shops are also involved in or 
 
 17 
 
 preparing to go into this business. This 
 should ease the situation to some 
 extent. 
 
 OTHER OBSERVATIONS AND SUGGESTIONS 
 
 COSTS ASSOCIATED WITH ATRS 
 
 All retrofitted ATRS systems require 
 that the roof bolter be removed from the 
 face for this purpose. Therefore, two 
 types of costs are involved with retro- 
 fitting of an ATRS: (1) costs occur- 
 ring from the loss of production and 
 (2) expenses attributable to the purchase 
 and installation of the ATRS system. The 
 costs resulting from loss of production 
 depend on a number of variables; most of 
 these are subjective in nature and cannot 
 be quantified easily. Although the 
 second cost category should be avail- 
 able from manufacturers or retrofit 
 shops, many medium- to large-sized opera- 
 tors typically schedule roof bolter over- 
 hauling with retrofitting of ATRS. This 
 makes it difficult to accurately estimate 
 the cost of retrofitting alone. The cost 
 of many ATRS systems for dual-boom bolt- 
 ers can be considered irrelevant since 
 most of them already have ATRS. The 
 costs associated with retrofitting thin- 
 to medium-seam roof bolters range from 
 about $6,000 to $15,000. 
 
 SOME CONCERNS ON THE ATRS LAW 
 AND RELATED MATTERS 
 
 Coal mine operators and safety direc- 
 tors expressed the following concerns 
 about the effects of the ATRS law: 
 
 1. Does the ATRS law prohibit the use 
 of any kind of posts at all in under- 
 ground mines at the working place? 
 
 2. Does the ATRS law prohibit the use 
 of posts (timber or mechanical) as addi- 
 tional temporary support with an ATRS if 
 roof conditions so demand? 
 
 3. Does the ATRS law prohibit the 
 presence of men beneath unsupported roof 
 under all circumstances? 
 
 The answers to these three questions 
 are all "no," so the fears of many mine 
 operators regarding the ATRS regulations 
 are unfounded. 
 
 In general, the overall reception to 
 the law has been positive. This under- 
 scores the safety features of the law, 
 which are recognized as desirable by all 
 concerned. Interviews with manufactur- 
 ers, mine operators, users, fabricators, 
 R&D engineers, etc., showed that most of 
 them are fully aware of the West Virginia 
 ATRS law. Although some reservations to 
 the law were observed as noted above, 
 these were primarily due to lack of over- 
 all understanding of its intent and ap- 
 plicability. Therefore, we reiterate the 
 need for a clarification of these con- 
 cerns by the West Virginia Department of 
 Mines. 
 
 REFERENCES 
 
 1. State of West Virginia. Department 
 of Mines Annual Report and Directory of 
 Mines, Years 1969 through 1979. 
 
 2. Chislaghi, C. T. , and T. E. Mar- 
 shall. Field Test of An Automated Tempo- 
 rary Roof Support (ATRS) on a Low-Coal, 
 
 Single Fixed-Head Roof -Bolting Machine 
 (Squirmer). BuMines TPR 119, 1982, 
 11 pp. 
 
 3. Peng, S. S. Coal Mine Ground Con- 
 trol. Wiley, 1978, pp. 31-32. 
 
18 
 
 FIELD TEST OF AN ATRS SYSTEM ON A LOW-COAL, SINGLE FIXED-HEAD 
 ROOF BOLTING MACHINE (SQUIRMER) 
 
 By Edward A. Barrett 1 and Thomas E. Marshall 2 
 
 ABSTRACT 
 
 An economical, remotely operated (auto- 
 mated) , temporary roof support (ATRS) has 
 been developed by the Bureau of Mines for 
 use on a single fixed-head roof bolting 
 machine (squirmer) that operates in low 
 coal seams (less than 42 in thick) . The 
 ATRS eliminates the need for squirmer 
 operators and helpers to go under unsup- 
 ported roof to set or remove temporary 
 support prior to or during the roof 
 bolting cycle — a task that annually ac- 
 counts for approximately 20 pet of all 
 
 roof fall fatalities. The ATRS can be 
 adapted to any squirmer used in the U.S. 
 low coal fields. A prototype ATRS was 
 field-tested at Imperial Colliery Co.'s 
 Mine No. 20 in Eskdale, WV. The Mine No. 
 20 amended roof -control plan, which re- 
 quires the use of the Bureau's ATRS as 
 temporary support during face bolting, 
 has been approved by the Mine Safety and 
 Health Administration (MSHA) , U.S. De- 
 partment of Labor. 
 
 INTRODUCTION 
 
 The Bureau developed an ATRS for 
 three reasons: (1) Squirmer operators 
 and helpers are exposed to unsupported 
 roof on a daily basis, (2) West Virginia 
 mine law 3 requires ATRS on squirmers, and 
 (3) original equipment manufacturers and 
 coal mine operators have not developed 
 adequate ATRS for squirmers. 
 
 A statutory provision of the Federal 
 Coal Mine Health and Safety Act of 1969 
 states that "No person shall proceed be- 
 yond the last permanent support unless 
 adequate temporary support is provided" 
 (30 CFR 75.200). However, since the law 
 was written, there have been no practical 
 means available that would allow squirmer 
 operators and helpers to set temporary 
 supports from under permanently supported 
 roof. Therefore, this provision was in- 
 terpreted to mean "In areas where per- 
 manent artificial support is required, 
 temporary support should be used until 
 
 1 Mining engineer. 
 
 2 Engineering technician. 
 Pittsburgh Research Center, Bureau of 
 Mines, Pittsburgh, PA. 
 
 3 West Virginia Administrative Regula- 
 tions, chapter 22-4, series 21, March 
 1981 . 
 
 such permanent support is installed," and 
 "Only those persons engaged in installing 
 temporary support should be allowed to 
 proceed beyond the last permanent sup- 
 port until such temporary supports are 
 installed" [30 CFR 75.200-13 (a) (1-2)]. 
 Annually, approximately 20 pet of all 
 roof fall fatalities involve miners who 
 have gone beyond the last permanent sup- 
 port to set or remove temporary roof sup- 
 port prior to or during the roof bolting 
 cycle. 
 
 Low coal mine operators in West Vir- 
 ginia need ATRS because the State mine 
 law requires that roof bolting machines 
 used in working places be equipped with 
 ATRS, regardless of coal seam height. 
 New machines must be equipped by 1982, 
 and all machines by 1984. 
 
 Over 3,500 squirmers are in use today 
 in southern West Virginia, eastern Ken- 
 tucky, and southwestern Virginia, and ap- 
 proximately 60 pet of these have no ATRS, 
 cab, or canopy. Because of space limita- 
 tions in low coal, not many ATRS have 
 been commercially developed for squirm- 
 ers, although many different ATRS systems 
 have been commercially developed for roof 
 bolting machines used in high coal. Most 
 
ATRS designed for squirmers reduce work- 
 space and operator visibility, creating a 
 situation that reduces or compromises the 
 existing safety level, with a greater 
 safety hazard to squirmer operators and 
 helpers working inby the last row of per- 
 manent support. 
 
 19 
 
 All design work and prototype fabrica- 
 tion of the Bureau ATRS was done by the 
 Roof Support Group at the Pittsburgh Re- 
 search Center. All fieldwork was done in 
 the No. 2 gas seam (36 to 42 in thick) at 
 Mine No. 20 of the Imperial Colliery Co. 
 in Eskdale, WV. 
 
 ACKNOWLEDGMENTS 
 
 The Bureau acknowledges the coopera- 
 tion it received from the Imperial Col- 
 liery Co. , especially the personnel of 
 Mine No. 20, who participated enthusias- 
 tically in the modifications and tests. 
 In addition, the Bureau acknowledges the 
 cooperation of the Mine Safety and Health 
 
 Administration (MSHA) , U.S. Department 
 of Labor; in particular, personnel of 
 the Bruceton Safety Technology Center 
 and the Mount Hope Subdistrict. Without 
 their technical suggestions and assist- 
 ance, this project could not have been 
 completed. 
 
 DESCRIPTION OF ATRS 
 
 The Bureau of Mines' ATRS is a 10-ft- 
 long, steel, wide-flange beam supported 
 by two double-acting, telescoping hydrau- 
 lic cylinders (fig. 1). A steel sleeve, 
 mounted on the bottom center of the beam, 
 is designed to fit over the top of the 
 squirmer drill head (fig. 2). The ATRS 
 is carried from place to place and from 
 row to row on the squirmer drill head 
 (fig. 3). During bolting it is connected 
 to the squirmer only by two hydraulic 
 lines (fig. 4). Because the ATRS weighs 
 only about 400 lb, the squirmer drill 
 head and boom do not have to be rebuilt 
 to carry it. Total cost of the beam and 
 cylinders is approximately $1,800. In- 
 house fabrication of the ATRS took 8 
 worker-hours. The Bureau piped the ATRS 
 hydraulic circuit at a cost of $150 and 
 32 worker-hours. 
 
 The Bureau's ATRS design meets MSHA's 
 general design requirements and West Vir- 
 ginia's design and operating requirements 
 for such support. Both hydraulic cyl- 
 inders supporting the ATRS have check 
 valves to prevent sudden collapse of the 
 ATRS in the event of a ruptured hydraulic 
 line or broken hydraulic fitting. In ad- 
 dition, the ATRS hydraulic circuit con- 
 tains an accumulator, charged by squirmer 
 line hydraulic pressure, which keeps the 
 ATRS firmly set against the mine roof 
 even if the roof rock is pulled up during 
 the bolting cycle. The ATRS can elasti- 
 cally support the minimum required dead- 
 weight load of 33,750 lb. 4 Figures 5 
 through 8 include all design drawings and 
 the hydraulic schematic. 
 
 SQUIRMER STREAMLINING 
 
 West Virginia State mine law requires 
 the streamlining of any roof bolting 
 machine before it can be retrofitted 
 with ATRS. Imperial Colliery personnel 
 streamlined a 15-yr-old squirmer for the 
 field test. The ATRS controls were lo- 
 cated 5 ft back from the drill head so 
 that they can be operated only from be- 
 neath permanently supported roof (fig. 
 9). Full tram controls are located with 
 the ATRS controls, and the full tram 
 
 speed was left at 150 ft/min. Inch-tram 
 controls were located at the drill sta- 
 tion, and inch tram speed was reduced to 
 65 ft/min. No ATRS controls were located 
 at the drill station. Other streamlin- 
 ing work included removal of the bolt 
 tray and tram deck, installation of low 
 volume-high torque tram motors, and 
 
 ^Capacity certified by a professional 
 engineer. 
 
20 
 
 FIGURE 1. - Bureau of Mines ATRS. 
 
 "IGURE 2. - ATRS mounted on drill head for transport from place to place. 
 
21 
 
 FIGURE 3. - ATRS carried from place to place. 
 
 FIGURE 4. - ATRS location during bolting. 
 
22 
 
 6- by 6- by 0.3-in web or 
 heavier steel, IO-ft long 
 
 .0, 
 
 Steel sleeve 
 
 Stiffeners, 7each side 
 
 Inside cylinder stops 
 
 I- by I- in bar steel 
 
 4 in long welded to 
 
 connection plate 
 
 FIGURE 5. - General assembly of ATRS. 
 
 moving the squirmer front wheels 8 in 
 forward to provide space for the ATRS and 
 full tram controls. Total cost of this 
 
 work was $5,500 and it 
 worker-hours to complete. 
 
 required 96 
 
 FIELD TEST AND RESULTS 
 
 With MSHA and West Virginia approval, 
 Imperial Colliery placed the ATRS in the 
 production cycle at Mine No. 20 for 5 
 months. Bolting was on 4-ft centers in 
 20-ft-wide entries and crosscuts. For 
 the Bureau's ATRS, the bolting cycle was 
 the following: 
 
 Step 1 . - The squirmer operator, at the 
 full tram controls (fig. 9), trams into 
 
 the center of an entry and stops when the 
 ATRS is under the last row of permanent 
 support. 
 
 Step 2 . - The operator lowers the drill 
 head and ATRS to the mine floor, using 
 the boom control located beside the full 
 tram and ATRS controls; moves from the 
 full tram position to the beam (ATRS) ; 
 and unhooks the hydraulic cylinder leg on 
 
23 
 
 L't 
 
 Hydraulic jack 
 
 FIGURE 6. = Detail of ATRS connection with- 
 out cylinder stop. 
 
 the operator side that is chained to the 
 beam, while the helper does the same to 
 the leg on the right side (fig. 10). 
 
 Step 3 . - The operator raises the drill 
 head and ATRS, using the boom control at 
 the drill station, just high enough to 
 let the legs hang down perpendicular to 
 the mine floor; locks the legs perpendic- 
 ular to the mine floor; moves back to the 
 full tram and ATRS controls; and trams 
 the squirmer inby. 
 
 Step 4 . - The operator stops when under 
 the last row of permanent support. The 
 ATRS is now 5 ft inby the last row of 
 permanent support and 5 ft from each rib. 
 
 Step 5 . - The operator places the ATRS 
 against the roof, using the boom control 
 located beside the full tram and ATRS 
 controls, and then extends the legs to 
 the mine floor, using the ATRS control, 
 until the beam is firmly set against the 
 roof and the legs are firmly set against 
 the mine floor. 
 
 6- by 6- by 0.3-in web or 
 heavier steel, 10 ft long 
 
 -Stiffener (7) 
 
 i-inweld, bottom flange 
 and web 
 
 — V i 
 
 ^4- in weld, all around 
 
 FIGURE 7. - End view of ATRS and connection 
 without cylinder stop. 
 
 Step 6 . - The operator lowers the drill 
 head away from the beam, using the boom 
 control located beside the full tram and 
 ATRS controls. 
 
 Step 7 . - At this point, the operator 
 moves to the drill station, pushes in the 
 diversion valve, which diverts all hy- 
 draulic fluid from the full tram and ATRS 
 circuits to the inch tram and drill cir- 
 cuits, and "inches" the squirmer to the 
 left rib to begin bolting. During bolt- 
 ing the squirmer is connected to the ATRS 
 only by two hydraulic lines (fig. 4). 
 
 Step 8 . - After a row of permanent sup- 
 port is installed, the operator raises 
 the drill head into the beam, using the 
 boom control at the drill station; pulls 
 out the diversion valve, which diverts 
 all the hydraulic fluid back to the full 
 tram and ATRS circuits from the inch tram 
 and drill circuits; moves to the full 
 tram and ATRS controls; and retracts the 
 legs, using the ATRS control. 
 
24 
 
 Boom 
 jack 
 
 Drill motor 
 V 
 
 Drill circuit 
 
 •Mvj~f| Relief valve 
 
 FIGURE 8. - Hydraulic schematic of ATRS for streamlining. 
 
 Step 9 . - The operator lowers the drill 
 head and ATRS, using the boom control lo- 
 cated beside the full tram and ATRS con- 
 trols, just enough to tram the squirmer 
 4 ft inby. 
 
 Step 10 . - When under the row of perma- 
 nent roof supoort that has just been in- 
 stalled, the operator stops and repeats 
 steps 5 through 9. This cycle is re- 
 peated until the last bolt is in place. 
 
 Step 11 . - Then the operator raises the 
 drill head into the beam, using the boom 
 control at the drill station; unlocks 
 the legs; pulls out the diversion valve; 
 moves to the ATRS controls; retracts the 
 legs; moves back to the drill station; 
 
 lowers the drill head and ATRS to the 
 mine floor, using the boom control at 
 the drill station; chains the leg on 
 the operator side to the beam, while the 
 helper does the same to the leg on the 
 right side; moves back to the full 
 tram and ATRS controls; and trams to the 
 next place, where steps 1 through 11 are 
 repeated. 
 
 No operating or maintenance problems 
 were encountered during the 5 months of 
 testing. With the addition of the ATRS, 
 the squirmer could still turn 180° within 
 the 20-ft-wide entries and crosscuts, and 
 could tram through check curtains and 
 line brattice without pulling them down. 
 Comparative time studies of the same 
 
25 
 
 FIGURE 9. - Control bank locations. 
 
 bolting crew showed that it took an aver- 
 age of 5 min less to bolt a place with 
 the ATRS than with mechanical jacks. The 
 bolting crew preferred the ATRS. After 
 testing, an amended roof control plan 
 requiring the use of the Bureau's ATRS 
 
 during face bolting at Mine No. 20 was 
 submitted by the Imperial Colliery Co. 
 and approved by MSHA (District 4, Mount 
 Hope Subdistrict, Montgomery Field 
 Office). 
 
 CONCLUSIONS 
 
 The Bureau 1 s ATRS eliminates the need 
 for squirmer operators and helpers to go 
 under unsupported roof to set or remove 
 temporary support prior to or during the 
 roof bolting cycle. The squirmer opera- 
 tor will always be under permanently sup- 
 ported roof while setting or removing the 
 ATRS and will not be able to bolt inby 
 the ATRS because of its size and position 
 in the entry. In addition, this inexpen- 
 sive and lightweight ATRS does not reduce 
 the squirmer operator's workspace. 
 
 The ATRS has the potential to be imme- 
 diately used in U.S. coal mines. Al- 
 though the Bureau's ATRS was field-tested 
 with only one squirmer, it can be adapted 
 to the drill head of any squirmer operat- 
 ing in low coal and it can be fabricated 
 in any mine shop. The ATRS can be retro- 
 fitted to the squirmer during mainte- 
 nance shifts if a streamlined squirmer is 
 available. 
 
26 
 
 FIGURE 10. - ATRS hydraulic cylinder legs unhooked. 
 
 Bolting does not stop if problems oc- 
 cur with the Bureau's ATRS, since it can 
 be removed from the area and bolting can 
 continue with mechanical jacks serving 
 as temporary supports. (If problems 
 arise or maintenance must be performed 
 on any other ATRS, the squirmer must be 
 taken out of production.) In addition, 
 this ATRS does not have to be reset for 
 each bolt hole as do the ring-type and 
 
 ironing-board-type ATRS. It is reset on- 
 ly after a complete row of bolts is in- 
 stalled. The Bureau's ATRS provides a 
 support envelope for the squirmer opera- 
 tor and does not obstruct the installa- 
 tion of bolts 2 ft from either rib. It 
 has the potential to drastically reduce 
 roof fall fatalities and injuries and 
 lead to increased productivity, if used 
 as outlined in this document. 
 
27 
 
 DEVELOPMENT OF AN ATRS SYSTEM FOR FAIRCHILD INC. ROOF DRILLS 
 
 By George Cobb 1 
 
 FAIRCHILD BOLTING MACHINES 
 
 Fairchild Inc.'s J-4 and J-6 roof bolt- 
 ers (fig. 1) have been in existence for 
 over 20 yr. When introduced to the in- 
 dustry they were immediately accepted 
 as the standard for bolting machines 
 with continuous mining in low seams. The 
 bolters were among the first to have a 
 fully enclosed gear-driven tram system, 
 which greatly decreased the interference 
 
 of mud or other foreign materials while 
 tramming. The Research and Development 
 Division of Fairchild, located in Beck- 
 ley, WV, has upgraded the bolter through 
 the years, such as increasing the hydrau- 
 lic capacity and installing a dual lift 
 on the bolter head. Now the Research and 
 Development Division is introducing an 
 ATRS system for the bolters. 
 
 ATRS WITH AN EXTENDED HEAD BOLTER 
 
 At first the Research and Development 
 engineers designed an ATRS system com- 
 patible with Fairchild' s original bolter 
 
 'Director of marketing, Fairchild Inc., 
 Beckley, WV. 
 
 designs. A prototype was developed, 
 tested underground, and brought back into 
 the laboratory for refinement. Mine op- 
 erators, the West Virginia Department of 
 Mines, West Virginia Tech University, and 
 MSHA provided valuable assistance during 
 
 FIGURE 1. o Standard Fairchild roof bolter without ATRS. 
 
28 
 
 this process. The ATRS system is now be- 
 ing fitted to the newest version of the 
 
 Fairchild bolter, whose extended head is 
 capable of reaching 46 in in height. 
 
 OPERATION OF THE ATRS 
 
 The ATRS is mounted on a stand and car- 
 ried by a lift arm weldment on the drill 
 head of the bolter. First, the operator 
 positions the ATRS stand just inby the 
 area to be bolted, lowers it to the bot- 
 tom by lowering the drill head, and 
 raises the ATRS jacks against the roof 
 (fig. 2). Each jack is capable of sup- 
 porting the roof load required by the 
 West Virginia Department of Mines (11,250 
 lb) without adversely affecting the frag- 
 ile roof strata. The ATRS must pressur- 
 ize against the roof before the drilling 
 and bolting controls become operational. 
 
 The operator then moves to the drilling 
 and bolting controls, backs the machine 
 away from the ATRS (figs. 3-4), and folds 
 
 back the lift arm weldment, thus giving 
 free access to the drill head. If the 
 ATRS has been efficiently positioned in 
 the entry, two bolts can be installed (5- 
 ft maximum spacing) without repositioning 
 the stand. To move the stand, the opera- 
 tor folds out the lift arm weldment, po- 
 sitions it under the stand, and lowers 
 the ATRS jacks to the desired tramming 
 height. He then raises the drill head to 
 pick up the stand and maneuvers the bolt- 
 er until the ATRS is repositioned (fig. 
 5) . He repeats this sequence until the 
 entire place is bolted according to the 
 approved mine bolting plan. A cab and 
 canopy at the rear of the bolter protect 
 the operator as he trams from place to 
 place (fig. 6). 
 
 FIGURE 2. - ATRS jacks extended. 
 
29 
 
 FIGURE 3. - Rear view of bolter backing away from ATRS stand. 
 
 FIGURE 4. » Front view of bolter backing away from ATRS stand. Note lift arm weldment. 
 
30 
 
 FIGURE 5. - Lift arm weldment repositioned beneath ATRS stand. 
 
 FIGURE 6. = Boom raised to carry ATRS. Note tram compartment at rear. 
 
STATUS OF THE PROGRAM 
 
 31 
 
 A second underground trial is scheduled 
 during May 1983. This should allow us to 
 finish the research and begin full devel- 
 opment of the new ATRS system. Although 
 West Virginia is the first State to re- 
 quire ATRS systems, we believe other 
 States will eventually require them. 
 
 Therefore, the Fairchild ATRS system is 
 being designed to achieve compliance with 
 regulations while providing the maximum 
 amount of safety, flexibility, and pro- 
 duction. We believe we will be able to 
 offer an ATRS retrofit kit to all West 
 Virginia customers by March 1984. 
 
32 
 
 RETROFIT ATRS SYSTEMS FOR ROOF BOLTERS 
 By Gary 0. Bledsoe 1 
 
 INTRODUCTION 
 
 G. 0. Bledsoe, Inc., is a small engi- 
 neering firm providing services to indus- 
 try, commercial development, contractors, 
 mining, and the general public. We pro- 
 vide professional engineering services on 
 canopies and ATRS systems to various man- 
 ufacturers and are most heavily involved 
 with A&M Welding and Manufacturing Co. , 
 Inc., Mullens, WV, in research and devel- 
 opment of retrofit packages for ATRS 
 systems. 
 
 G. 0. Bledsoe, Inc. , is in a rather 
 unique position because we do not repre- 
 sent a manufacturer and are primarily 
 
 concerned with the retrofit industry in- 
 stead of new equipment. For this reason 
 we can look at a variety of designs with- 
 out having to sell a particular product 
 line. In the development of ATRS sys- 
 tems, we have tried to standardize as 
 much as possible; however, we found this 
 to be very difficult because almost every 
 retrofit is a custom design package for 
 each manufacturer's equipment and each 
 variation of each model. This paper dis- 
 cusses the advantages and disadvantages 
 of all four types of retrofit ATRS sys- 
 tems available today. 
 
 CHARACTERISTICS OF RETROFIT ATRS SYSTEMS 
 
 A good retrofit ATRS system should 
 be (1) rugged enough to withstand roof 
 loads and lateral impacts, (2) as light 
 as possible to improve maneuverabil- 
 ity, (3) versatile enough to meet a vari- 
 ety of roof conditions, and (4) easy 
 to operate and maintain. Also, to sa- 
 tisfy ATRS regulations, the retrofit sys- 
 tem must be designed such that the 
 machine operator is always under perma- 
 nently supported roof while installing 
 the ATRS, and the hydraulic ATRS sup- 
 port jack(s) must contain a pilot check 
 valve(s) to prevent accidental collapse. 
 Unfortunately, many existing roof bolt- 
 ers were not designed to accommodate 
 ATRS structures. Furthermore, some ma- 
 chines with ATRS systems were not de- 
 signed to meet the requirements of the 
 ATRS regulations now in place. There- 
 fore, many existing machines will have 
 
 to be modified in some 
 compliance. 
 
 manner to achieve 
 
 Installing a retrofit ATRS system is 
 not a simple matter of attaching a roof 
 support structure to the bolter; the ma- 
 chine itself must be modified substan- 
 tially to obtain a good, "legal" ATRS 
 system. Possible machine modifications 
 include (1) adding inch-tram and/or ATRS 
 positioning controls, (2) relocating ex- 
 isting controls, (3) adding or modifying 
 the tramming deck and canopy, (4) revis- 
 ing structural framework to support the 
 ATRS structure, (5) adding newer, more 
 powerful tram motors, and (6) general 
 overhaul of the machine to obtain opti- 
 mum performance. The cost of performing 
 these modifications is often equal to or 
 greater than the cost of the ATRS system 
 itself. 
 
 TYPES OF RETROFIT ATRS SYSTEMS 
 
 RING-TYPE 
 
 Figures 1-3 show a typical ring-type 
 ATRS system on a single-head roof bolter. 
 
 1 President, G. O. Bledsoe, Inc., Beck- 
 ley, WV. 
 
 Figure 1 shows the system deployed in a 
 mine entry, and figures 2 and 3 show the 
 system when it was first installed on 
 the bolter in a rebuild shop. The ring 
 in these figures is 36 in in diameter 
 (smaller or larger rings can be used) and 
 is centered around the point where the 
 
33 
 
 FIGURE 1. - Ring-type retrofit ATRS deployed in mine entry. 
 
 FIGURE 2. » Ring-type ATRS being installed in rebuild shop - front view. 
 
34 
 
 FIGURE 3. = Ring-type ATRS in rebuild shop = rear view. 
 
35 
 
 drill steel enters the mine roof. The 
 ring is mounted on a pair of steel arms 
 and is raised to the roof by a hydraulic 
 jack(s). It must be retracted and reset 
 prior to each roof bolt installation be- 
 cause the ring only supports the mine 
 roof in the immediate vicinity of each 
 roof bolt hole. 
 
 Since the ring-type ATRS system is rel- 
 atively small and maneuverable compared 
 to other ATRS systems, many mine opera- 
 tors feel it is the best system avail- 
 able. However, one disadvantage of the 
 ring design is that it usually contacts 
 the roof at only two points; thus, high 
 twisting stresses can occur in the sup- 
 port arms when the ring tries to con- 
 form to the irregular contour of the mine 
 roof. The designs of some ring and sup- 
 port arm structures result in roof con- 
 tact at only one point, further increas- 
 ing the twisting stresses. 
 
 Installation of a retrofit ring-type 
 ATRS system on a high-coal machine is 
 rather simple — the support arms, pivots, 
 and jacks can be welded directly on top 
 of the machine frame. In low coal, how- 
 ever, the ring must often be dropped 
 below the machine frame height, so the 
 support arms and pivots must also be 
 recessed below the frame. In most cases, 
 this modification is quite difficult 
 and expensive because the machine must 
 be stripped down to its main frame to 
 provide the necessary clearances. Ring- 
 type retrofit ATRS systems appear to be 
 applicable to bolters in seams as low as 
 32 in. 
 
 H-FRAME 
 
 Figures 4 and 5 show the H-frame retro- 
 fit ATRS system designed by G. 0. Bled- 
 soe, Inc. , and fabricated by A&M Welding 
 and Manufacturing Co. for single-head 
 roof bolters. Although the H-frame, like 
 the ring-type ATRS, was designed to sup- 
 port only the roof area in the vicinity 
 of one bolt, we prefer it to the ring 
 type because (1) the H-frame will usual- 
 ly contact the mine roof at three or four 
 
 points, versus one or two for the ring 
 type and (2) the cantilevered design of 
 the H-frame allows it to support more 
 roof area than the ring type (an 8- by 
 8-ft versus a 5- by 5-ft area). Figure 
 6 shows an alternative version of the 
 H-frame design; in this case, the middle 
 portion of the "H" in figures 4 and 5 is 
 eliminated, and two separate hydraulic 
 jacks are used to raise the remaining two 
 portions of the roof support structure. 
 This design provides more flexibility in 
 uneven roof conditions than either the 
 H-frame or the ring-type ATRS. 
 
 The H-frame and modified H-frame retro- 
 fit ATRS systems share two of the disad- 
 vantages of ring-type retrofit systems. 
 First, the retrofit process is usually 
 rather difficult and expensive, involving 
 changes to the tramming station, bolter 
 frame, and machine hydraulic system. 
 Second, the H-frame has limited applica- 
 tion to very low coal. Note that the 
 H-frame structures in figures 4, 5, and 6 
 are made of 4-in-deep structural tubing 
 that would increase the tramming height 
 of the bolters unless special modifica- 
 tions were made. For this reason, G. 0. 
 Bledsoe and A&M Welding have developed a 
 low-profile H-frame made of 1-in-thick 
 steel plate, reinforced with stiffeners. 
 The lowest tramming height attainable 
 with the low-profile H-frame is approxi- 
 mately 32 in. 
 
 BAR-TYPE 
 
 Bar-type ATRS systems are different 
 from ring-type or H-frame designs because 
 the bar is usually designed to support 
 the roof area normally supported by one 
 complete row of roof bolts (sometimes two 
 rows) rather than just one bolt. Because 
 of this , many operators believe the bar- 
 type system is inherently safer than any 
 single-bolt system. In addition, the 
 bar-type system can improve productivity 
 because a complete row of bolts can be 
 installed with each ATRS setup. Almost 
 all newly manufactured dual-head roof 
 bolters contain some form of bar-type 
 ATRS system. 
 
36 
 
 FIGURE 4. - H=frame retrofit ATRS on single=head bolter. Note streamlined control station. 
 
 FIGURE 5. - H-frame retrofit ATRS deployed in mine entry. 
 
37 
 
 FIGURE 6. - Alternative H-frame ATRS - center portion removed. 
 
 In terms of retrofit, however, the bar- 
 type ATRS system has some distinct dis- 
 advantages compared to ring-type and 
 H-frame systems, especially with the 
 small single-head bolters that are most 
 likely to require retrofitting. Because 
 the bar is usually heavier, bulkier, and 
 cantilevered farther forward than ei- 
 ther the ring or the H-frame, a bolter 
 equipped with a bar-type retrofit system 
 may be difficult to tram and maneuver 
 around corners. The bar may also be dif- 
 ficult to set up in working places where 
 the face and ribs do not form rectangular 
 corners; this often occurs in conven- 
 tional sections where the coal is blasted 
 rather than cut from the face. The extra 
 time required for these maneuvering tasks 
 may totally negate the productivity ad- 
 vantages gained by the ability to install 
 
 more than one bolt per ATRS set up. That 
 is, if a ring or H-frame ATRS system is 
 simple and responds rapidly, it could re- 
 sult in a faster overall bolting cycle 
 time than a bar-type system. Further- 
 more, the heavier, bulkier bar often re- 
 quires a far more difficult (and some- 
 times impossible) retrofit task than the 
 other two methods. Thus far, only one 
 retrofit bar-type system, designed by the 
 Bureau of Mines, is now available to coal 
 mine operators. 
 
 JACK-TYPE 
 
 The jack-type ATRS system is as simple 
 as implied by its name — a single hydrau- 
 lic jack (or a set of jacks) is thrust 
 directly against the roof to provide sup- 
 port in the immediate vicinity of the 
 
38 
 
 jack itself. Although its coverage is 
 very limited compared to that of the 
 other three types of ATRS systems de- 
 scribed above, it is much simpler and can 
 be retrofitted more easily to the bolting 
 machines . 
 
 The primary application of the jack- 
 type ATRS system thus far has been as a 
 supplementary support, used in conjunc- 
 tion with a bar-type system. However, 
 the jack-type system is probably the most 
 appropriate system for very low coal 
 seams because it lacks the ring, H-frame, 
 
 or bar-type structures that require 
 greater vertical clearance. The lack of 
 a large load-bearing support structure 
 on top of the jacks also makes the jack- 
 type system less susceptible to machine- 
 induced ATRS failure. That is, the up- 
 ward thrust of the jacks on the ring, 
 H-frame, or bar can sometimes induce 
 stresses that exceed the rock load for 
 which the structures were designed. Spe- 
 cial care must be taken when designing 
 these three systems to avoid excess up- 
 ward thrust loads. 
 
 NEED FOR RETROFIT ATRS SYSTEMS 
 
 Considering that most of the single- 
 head roof bolters now being used in 
 southern West Virginia do not contain 
 ATRS systems, a great deal of retrofit- 
 ting work will need to be done in order 
 to comply with the March 1984 deadline 
 specified in the West Virginia ATRS regu- 
 lation. G. 0. Bledsoe, Inc, , and A&M 
 Welding and Manufacturing Co. are in a 
 position to help meet these needs because 
 we have developed and installed retro- 
 fit ATRS designs for Fletcher, Lee- 
 Norse, Acme, and FMC (Galis) roof bolt- 
 ers. About 30 pet of all retrofit ATRS 
 systems now being used in the Appalachian 
 coalfields have been designed and in- 
 stalled by our companies. 
 
 Mine operators must remember that sim- 
 ple retrofit kits for their machines are 
 not sufficient; the systems must be in- 
 stalled by persons with intimate knowl- 
 edge of both the ATRS requirements and 
 
 the design of the roof bolter itself. In 
 each case, the mine operator must decide 
 whether to retrofit the existing bolt- 
 er or replace it with a new machine de- 
 signed specifically to accommodate an 
 ATRS system. 
 
 Although retrofits are not cheap, they 
 are less expensive than buying a new 
 machine; on the other hand, a newly de- 
 signed machine will often contain a neat- 
 er, more advanced, and more maneuverable 
 ATRS package. If capital is available, 
 the new machine option is probably the 
 best one to choose. Most small mine op- 
 erators, however, will not be able to 
 afford new machines; therefore, they 
 should consider the advantages and disad- 
 vantages of each type of retrofit system 
 very closely. It is hoped that this pa- 
 per will help them make their decisions 
 regarding retrofit ATRS systems. 
 
THE SCHROEDER FRONTRUNNER ROOF BOLTER WITH ATRS SYSTEM 
 By Gus Schroeder 1 
 
 39 
 
 The Frontrunner is a twin-head bolter 
 designed to operate in coal seams from 55 
 to 84 in high. To allow the machine op- 
 erators to work in the safest possible 
 conditions, both operators are able to 
 perform all functions associated with 
 roof bolting, including tramming, from a 
 single, well-protected position on the 
 machine. The Frontrunner' s design places 
 the operators in two compartments located 
 at the front of the machine (figs. 1-2). 
 Each compartment is covered by a protec- 
 tive canopy that can be adjusted hydrau- 
 lically to afford the maximum height 
 within the compartment at all times. 
 
 During bolting operations, the primary 
 operator protection is provided by an 
 
 ' Schroeder 
 Rocks, PA. 
 
 Brothers Corp., McKees 
 
 ATRS located directly in front of the op- 
 erators' compartments. Drilling is done 
 with a mast-type assembly which provides 
 for hands-off drilling by incorporating 
 both a deep drill chuck and a practical 
 drill steel centralizer. The drill masts 
 are located at the front of each opera- 
 tor's compartment (fig. 3) and can be 
 shifted hydraulically across the full 
 length of the compartment. The compart- 
 ments themselves can be expanded lateral- 
 ly to a fully extended width of 185 in. 
 Figure 4 shows the compartments in their 
 fully retracted positions, and figure 5 
 shows the left compartment extended to- 
 ward the rib. Because both the compart- 
 ments and the drill masts can be adjusted 
 laterally, a complete row of bolts can be 
 installed without having to reposition 
 the entire machine. 
 
 FIGURE 1. - Overall view of FRONTRUNNER roof bolter - ATRS lowered. 
 
40 
 
 FIGURE 2. - Overall view of FRONTRUNNER roof bolter - ATRS raised. 
 
 FIGURE 3. - Side view of sliding drill mast. 
 
41 
 
 FIGURE 4. - Rear view - compartments retracted. 
 
 FIGURE 5. - Left compartment extended toward rib. Note tool tray. 
 
42 
 
 The following sequence occurs during 
 the normal installation of one set of 
 bolts (four bolts per row). The operator 
 trams the Frontrunner into the center of 
 the working place and spots the drill 
 heads for the first row of bolt holes. 
 He then raises the ATRS to support the 
 roof and lowers both compartments to the 
 floor. The drill masts are then posi- 
 tioned inward for proper hole location, 
 and the center two bolts are installed. 
 The compartments are then repositioned 
 outward toward the mine ribs, the drill 
 masts are repositioned, and the outer two 
 bolts are installed. 
 
 After the first complete row of bolts 
 is installed, the operator slightly col- 
 lapses the ATRS, trams forward to spot 
 the drill heads for the next row, and re- 
 sets the ATRS. During this brief period 
 of repositioning, protection is provided 
 for the operators by the canopies over 
 each compartment. Because the operators 
 
 always face one another within their com- 
 partments (fig. 6), each has full view of 
 the other during both drilling and tram- 
 ming. From their seated positions the 
 operators can easily reach the drill 
 heads in front of them and the tool trays 
 behind them (fig. 5). Each tool tray 
 is connected to the back of the opera- 
 tor's compartment and follows the com- 
 partment as it expands. Access to drill 
 steels, roof bolts, and other necessary 
 supplies remains convenient regardless 
 of where the compartments are posi- 
 tioned. The design of the Frontrunner' s 
 operating compartments, therefore, pro- 
 vides a safe, efficient, and comfortable 
 working environment. 
 
 Safety has also been a key considera- 
 tion in the design of the Frontrunner' s 
 operating controls. Control levers 
 (figs. 7-8) have been grouped together 
 in logical relationship to the sequence 
 of their function in the bolting cycle. 
 
 FIGURE 6. - Bolter operators maintain visual communication during bolting cycle. 
 
43 
 
 FIGURE 7. • Control layout within operator compartment. 
 
 FIGURE 8. - Closeup of ATRS controls. 
 
44 
 
 Maximum speeds of the various functions 
 have been set at levels that allow 
 the operator to maintain control of the 
 machine. The left side operating com- 
 partment contains the primary control 
 system with individual controls for 
 (1) tramming, (2) raising and lowering 
 the ATRS, (3) moving the left compart- 
 ment, (4) raising and lowering the left 
 side canopy, and (5) operating the left 
 side drill head and mast. The right side 
 operating compartment contains controls 
 only for the right side drill head and 
 mast, movement of the right compartment, 
 and height adjustment of the right side 
 canopy. Panic bars that stop all opera- 
 tions are conveniently located in both 
 compartments . 
 
 To ensure that the Front runner can be 
 trammed easily, the steering system is 
 similar to that found in an automobile. 
 Tramming speed is governed by a foot- 
 operated accelerator which controls speed 
 from to 88 ft/min. Steering is accom- 
 plished with a steering wheel rather than 
 the lever arrangement found on most min- 
 ing machines. If the wheel is turned 
 right, the machine turns right. If the 
 wheel is turned left, the machine turns 
 left. The turning radius of the machine 
 becomes tighter as the wheel is turned. 
 This automotive-type steering system al- 
 lows even inexperienced machine operators 
 to tram the machine safely. 
 
 Location of the operator at the front 
 end of the Frontrunner affords maximum 
 visibility while tramming forward. When 
 tramming in reverse, he or she can obtain 
 an undisturbed line of sight down the 
 side of the machine by moving the left 
 side compartment slightly out from the 
 main frame. When the machine is in the 
 tram mode, each operator retains the 
 ability to raise and lower the height of 
 his or her compartment and canopy to com- 
 pensate for variations in seam height. 
 When only one person is on the machine 
 during tramming, controls for the right 
 side canopy and compartment can be 
 switched over to the left side compart- 
 ment. The Frontrunner* s design allows 
 
 both operators to ride inside the protec- 
 tive compartments while the machine is 
 moving from one working place to another. 
 This feature reduces the possibility that 
 the operators can become pinned between 
 the machine and the mine rib. 
 
 Both the tram and ATRS functions on the 
 Frontrunner can also be controlled re- 
 motely (fig. 9). A control box connected 
 to the rear of the machine by an electri- 
 cal cable allows machine positioning and 
 setting of the ATRS to be done without 
 either operator being physically located 
 on the machine. 
 
 As stated earlier, the ATRS provides 
 the primary protection against roof falls 
 while the Frontrunner is in the drilling 
 mode. When fully collapsed (fig. 10) , 
 the scissors-type ATRS is only 38 in 
 high, which is less than the height of 
 the machine frame. When fully expanded 
 (fig. 11), the ATRS reaches a height of 
 slightly over 9 ft. Use of the scissors- 
 type ATRS design allows for about 6 ft of 
 height variation in the ATRS without us- 
 ing telescoping hydraulic cylinders. 
 
 The ATRS is expanded by means of three 
 double-acting hydraulic cylinders. The 
 cross beam is raised and lowered by two 
 cylinders which drive the scissors link- 
 age arms. Hydraulic oil is furnished 
 from a single control valve and then di- 
 vided equally to each cylinder. A third 
 cylinder, located in the main ATRS sup- 
 port housing, vertically lowers 1 ft from 
 the housing to maintain ground contact 
 (fig. 12). All three of these cylinders 
 incorporate the required built-in pilot 
 check valves . 
 
 The main support housing of the ATRS is 
 mounted in a pivoted fashion on the boom, 
 allowing the entire ATRS to be tilted by 
 means of another hydraulic cylinder (fig. 
 13). This allows the ATRS to be adjusted 
 to conform to the contour of each working 
 face so that the last row of bolts can be 
 installed as close to the face as possi- 
 ble. The ATRS boom itself can also be 
 raised and lowered hydraulically. In 
 
45 
 
 FIGURE 9. - Optional remote control tramming from rear of bolter. 
 
 FIGURE 10. - ATRS collapsed - 38=in overall height. 
 
46 
 
 FIGURE 11. - ATRS fully extended to 9-ft height. 
 
 i^pvpp p.. . 
 
 ::M'?P&PPr-. 
 
 FIGURE 12. - ATRS stab foot maintains ground contact. 
 
47 
 
 FIGURE 13. - ATRS beam tilted toward face. 
 
 total, four controls are used to operate 
 the ATRS: boom raise and lower; ATRS 
 tilt; ATRS foot; and ATRS expand and con- 
 tract. The controls are grouped together 
 in the left side operator's compartment. 
 
 Small rocker beams are located at each 
 end of the main cross beam of the ATRS, 
 and the cross beam itself is pivoted at 
 the center. These features allow the 
 ATRS to conform to the coal seam roof 
 line. During periods when the ATRS is 
 not set, the cross beam is maintained in 
 a horizontal position by two large drop 
 coil springs which run from the cross 
 beam to the ATRS scissors arms. To pre- 
 vent any overstressing of the ATRS assem- 
 bly that might occur as a result of acci- 
 dentally bumping the mine rib or roof 
 while tramming, all the pivot points have 
 
 been designed to have some degree of 
 freedom of movement. 
 
 In summary, the major safety feature of 
 the Frontrunner roof bolter is that its 
 design allows both machine operators to 
 perform all roof bolting functions, in- 
 cluding tramming, from a single location 
 on the machine. The use of two canopy- 
 equipped operator compartments and an 
 ATRS system provides protection for both 
 operators at all times. Although our 
 ATRS system was designed for use on the 
 Frontrunner bolter, Schroeder Brothers 
 may explore the possibility of adapting 
 it to other dual-head roof bolters. Our 
 ATRS system meets all applicable ATRS 
 requirements outlined in the West Vir- 
 ginia Mine Regulations. 
 
48 
 
 REMOTELY ACTUATED TEMPORARY SUPPORT (RATS) 
 FOR FMC UNDERGROUND MINING EQUIPMENT 
 
 By Martin D. Wotring 
 
 The 1969 Coal Mine Health and Safety 
 Act required the installation of canopies 
 on face equipment. Considerable opposi- 
 tion to the use of the canopies in low 
 seams caused MSHA to waive the original 
 canopy requirements in seams under 42 in. 
 This left a large percentage of coal 
 miners without any form of roof fall pro- 
 tection. An analysis of fatalities due 
 to roof falls for 1972-75 revealed that 
 roof bolters and their helpers suffer the 
 largest percentage of fatalities (17.5 
 pet) , and that setting temporary posts or 
 jacks is the activity with the largest 
 percentage of fatalities (18.5 pet). Of 
 course, since the roof bolter and helper 
 usually set the temporary support during 
 the normal course of the bolting opera- 
 tion, these percentages indicated the 
 need for some method to prevent a worker 
 from going beyond permanent roof support 
 to set these posts or jacks. 
 
 FMC first installed remotely actuated 
 supports (RATS) on dual-boom roof bolters 
 in 1974. This "ironing board" style RATS 
 was used in place of the canopies over 
 the drilling stations (fig. 1). At the 
 1976 American Mining Congress convention 
 in Detroit, FMC displayed its first roof 
 drill with a ring-type roof support (fig. 
 2) This was a single-boom drill that also 
 incorporated a drill steel guide within 
 the support and a canopy over the opera- 
 tor's deck. At the same time, ring-type 
 and ironing-board-type RATS were being 
 tried on existing single-boom drills as 
 retrofit kits (figs. 3-4). Dual-boom 
 roof bolters with ring-type RATS and 
 drilling canopies (fig. 5) were also 
 developed. 
 
 1 Lead engineer, roof bolters, FMC 
 Corp., Mining Equipment Division, Fair- 
 mont, WV. 
 
 Dual-boom roof bolters with beam-type 
 RATS (fig. 6) became available in 1977. 
 This type of RATS features four roof con- 
 tact pads which are less than 5 ft apart. 
 The pads swivel, as does a rocker arm to 
 which the pads are connected. This per- 
 mits the RATS to conform to uneven tops. 
 The overall width of the beam-type 
 RATS can be 8 to 10 ft. Figure 7 shows 
 a beam-type RATS on a dual-boom drill de- 
 signed for angle bolting. 
 
 FMC introduced a single-boom roof drill 
 with a beam RATS at the 1980 American 
 Mining Congress convention in Chicago 
 (fig. 8). This machine has essentially 
 the same type beam support as a dual-boom 
 bolter, but the drill unit pivots hori- 
 zontally to allow the installation of a 
 complete row of four bolts on 4-ft cen- 
 ters. It has the capability to extend to 
 allow the row of bolts to be installed 
 in a straight line across the entry. 
 
 A single-mast drill was exhibited at 
 the 1982 American Mining Congress conven- 
 tion in Las Vegas. This machine has 
 space in the operator's deck for both the 
 driller and helper, and both are covered 
 by a canopy. The RATS is attached to the 
 deck just ahead of the mast. The deck 
 can be lowered to the floor and the RATS 
 engaged against the roof for support, 
 thus protecting both workers. 
 
 FMC has also been involved with two Bu- 
 reau of Mines roof support research pro- 
 grams. One was to design, build, and 
 test a lightweight, manually installed 
 support jack (fig. 9). This jack is 
 self-contained, is hydraulically actuated 
 with a lanyard release, supports 22 tons, 
 and weighs only 54 lb. 
 
49 
 
 FIGURE 1. - Dual-boom roof bolter with ironing°boarcUtype RATS. 
 
 FIGURE 2. - Single=boom roof bolter with ring-type RATS, operator's deck, and canopy. 
 
50 
 
 FIGURE 3. - Single-boom roof bolter with retrofit ring-type RATS. 
 
 rffflft 
 
 FIGURE 4. - Single=boom roof bolter with ironing=board=type RATS. 
 
51 
 
 FIGURE 5. - Dual-boom roof bolter with ring-type RATS. 
 
 FIGURE 6. - Dual-boom roof bolter with beam-type RATS. 
 
52 
 
 FIGURE 7. - Dual-boom angle bolter with beam-type RATS. 
 
 FIGURE 8. - Single-boom roof bolter with beam-type RATS. 
 
53 
 
 FIGURE 9. - Lightweight temporary roof support jack. 
 
 .*» 
 
 £:i 
 
 FIGURE 10. - Mobile roof support (MRS) prototype machine. 
 
54 
 
 The other project called for the de- 
 sign, construction, and test of a mobile 
 roof support (MRS) , as shown in figure 
 10. This machine was tested underground 
 at Inland Steel's Sesser Mine in Illi- 
 nois. The four hydraulic jacks mounted 
 on the battery-powered chassis are each 
 
 capable of supporting 30 tons. There 
 were a few problems with the prototype, 
 but a second generation MRS has been 
 built in conjunction with the Bureau of 
 Mines and Southern Utah Fuel Co. Tests 
 have not been completed. 
 
55 
 
 ROOF SUPPORT SYSTEMS FOR FLETCHER ROOF DRILLS 
 By Douglas R. Hardman 1 
 
 INTRODUCTION 
 
 The first automated temporary roof sup- 
 port system (ATRS) for a roof bolting ma- 
 chine was developed by J. H. Fletcher & 
 Co. in mid-1971 and was delivered to a 
 mine in November 1971. In 1972, a system 
 was exhibited at the coal show in Cleve- 
 land, and several retrofit kits were de- 
 veloped. Since about mid-1973 most of 
 our dual-head roof bolters have had a 
 roof support system of some type. 
 
 Although we have some standard mod- 
 els of equipment, we also make custom- 
 designed machines; therefore, we have 
 several different ATRS configurations. 
 While we have built a few ATRS systems 
 that are attached to and move with the 
 drilling unit, our main thrust has been 
 toward systems that are independent of 
 the drilling boom. This allows us to 
 keep the worker under supported roof 
 while maneuvering the drill head from 
 
 the drilling controls. This paper cov- 
 ers roof supports on our different stan- 
 dard machines, custom-designed systems, 
 single-head systems, and retrofits. 
 
 All of the roof support systems dis- 
 cussed in this paper conform to the West 
 Virginia regulations for ATRS systems, 
 but this does not necessarily mean they 
 will comply with every mine roof support 
 plan approved by MSHA. When a machine 
 with a new ATRS is put into service, the 
 mine operator must file a request for 
 change to the roof support plan with 
 MSHA. Over the past 10 to 12 yr we have 
 worked very closely with roof support 
 people at MSHA Technical Support and 
 the local MSHA representatives. In all 
 cases, their help and input have proved 
 invaluable, and we have never had any 
 problems in working out a viable 
 solution. 
 
 TYPES OF FLETCHER ATRS SYSTEMS 
 
 Most of the machines we build are 
 dual head, for which we have three main 
 types of TRS systems: the H-style, the 
 T-style, and the scissors style. The 
 H-style, shown in figure 1, is used on 
 our model DDM machines and is designed to 
 elastically support a maximum load of 
 67,500 lb. The purpose of this type of 
 system is to allow the operator to in- 
 stall two rows of bolts without having to 
 reposition the machine. 
 
 The T-style TRS is shown in figure 2. 
 This type of roof support is used on most 
 of our dual-head machines with various 
 mounting configurations, depending on the 
 model of machine, mine conditions, and 
 working height. Most of these T-style 
 units sump and tilt to allow for a more 
 
 1 Manager, Engineering Services, J. H. 
 Fletcher & Co., Huntington, WV. 
 
 compact package when tramming from place 
 to place. These sump and tilt functions, 
 along with features like front end lift 
 and wagon brakes, are controlled from 
 the inch-tram area as well as the tram 
 deck. 
 
 Contact pads 
 
 ATRS support 
 member assembly 
 
 TRS support frame 
 
 Outer boom 
 
 Inner boom 
 
 FIGURE 1.- H-style ATRS. 
 
56 
 
 The scissors TRS shown in figure 3 is a 
 variation of the T-style and was devel- 
 oped to gain increased versatility in 
 low-seam operations. This system will 
 collapse to a height of 30 in with 6 in 
 of underclearance and extend to a maxi- 
 mum height of 8 ft if the need arises. A 
 version of the scissors has also been 
 built that will collapse to 24 in with a 
 60-in extension for operation in 29- to 
 30-in conditions. This type of system is 
 best suited for mining heights below 4 
 ft. The 8-ft maximum height allows for 
 excellent flexibility when conditions 
 vary, but as the beam goes higher, the 
 mechanics of the linkage cause it to rise 
 at a slower rate. 
 
 ATRS beam assembly 
 
 Safety post assembly 
 
 ATRS tilt cylinder 
 ATRS frame assembly 
 
 ATRS skid foot assembly 
 
 FIGURE 2. - T-style ATRS. 
 
 It also should be noted that the beam 
 rises in an arc, which necessitates sump- 
 ing the ATRS in and out for varying roof 
 conditions. The beam and support struc- 
 ture for the T and scissors roof supports 
 are designed to elastically support a 
 load of 38,250 lb at a maximum width of 
 12 ft. 
 
 Most of our ATRS systems are supplied 
 with adjustable rocker pads which allow 
 the width of the support envelope to be 
 varied in 6-in increments from 8 to 10 ft 
 on one model and from 10 to 12 ft on 
 another. All of these roof supports are 
 actuated by hydraulic cylinders equipped 
 with integral pilot-operated check valves 
 which have a design pressure rating of 
 10,000 psi. The schematic in figure 4 
 shows that the circuit is designed to 
 maintain thrust against the roof. When 
 the control valve section is actuated to 
 extend, the cylinder flow is directed to 
 the V2 port in the relief and check valve 
 package. A built-in relief valve on the 
 up-stroke side of the circuit allows the 
 pressure setting on the system to be al- 
 tered. Downstream from the relief valve 
 there is a pilot-operated check valve in 
 the line which acts to keep the accumula- 
 tor charged. The accumulator usually has 
 a capacity of 1 gal and is in the cir- 
 cuit to provide makeup oil to the system, 
 which helps offset things like settling 
 
 Tension link assembly 
 
 
 ATRS bar assembly 
 
 Lift cylinder 
 
 Compression link 
 
 FIGURE 3. - Scissors support system. 
 
 Foot assembly 
 
57 
 
 Check and relief 
 valve package 
 
 -& 
 
 Roof support 
 cylinder 
 
 c 
 
 s> 
 
 -fc- 
 
 / / 
 
 ) 
 
 ACC ,h L 
 
 Accumulator 
 
 C 
 
 IV, 
 
 Control 
 valve section 
 
 ,JL 
 
 1 
 
 $ 
 
 1 
 
 -~^J,800ps 
 
 FIGURE 4. - Schematic of ATRS hydraulic system. 
 
 of the foot into the floor and minor main hydraulic tank. This lets oil out 
 
 leakage at the cylinder. In the package 
 valve the return side of the cylinder is 
 connected, through an orifice, to the 
 
 of the top of the cylinder when it is 
 trying to readjust due to accumulator 
 pressure. 
 
 DUAL-HEAD ROOF BOLTER MODELS 
 
 One of the standard dual-head machines 
 built by Fletcher is the model DDM (figs. 
 5-6), which uses the H-style ATRS. This 
 system allows the operator to install two 
 rows of bolts with one machine setup. 
 This is made possible by mounting the 
 drill unit on a boom that swings 7 ft 
 from the machine center line and sumps 
 forward 9 ft. It is also possible to in- 
 stall a third row of bolts when the inby 
 cross beam is within 5 ft of the face. 
 
 The ATRS controls for this machine are 
 located in the tram deck along with con- 
 trols for brakes, stab jacks, and boom 
 swing. It should also be noted that each 
 drilling unit is equipped with a safety 
 post that can be considered part of the 
 roof control system in some cases. Fig- 
 ure 6 shows an example of a special DDM 
 with offset drilling units which was 
 designed to provide operator protection 
 in mines where bad rib conditions are a 
 major concern. Machines of this type 
 have been operating very effectively for 
 years. 
 
 Figures 7 and 8 show two versions of a 
 model DDO machine. There are quite a few 
 different variations of this model, rang- 
 ing from machines that will work in seam 
 heights of 30 in to units that will 
 
 operate in 8 ft of coal. All of these 
 machines either use a T (fig. 7) or scis- 
 sors (fig. 8) ATRS, depending on the 
 height and operating conditions. The 
 drill booms swing 9 ft from center and 
 are equipped with 12-, 18-, or 24-in 
 sumps. The positioning and ATRS controls 
 are located over the left front wheel, 
 and the unit must be moved after each row 
 of bolts. In most cases a canopy is pro- 
 vided over the drill controls, but in 
 some instances the canopy support cylin- 
 ders have been approved as safety posts 
 in lieu of canopies. In either case, as 
 the operator moves from hole to hole in- 
 stalling a row of bolts parallel to the 
 face, the main roof support system re- 
 mains in place. 
 
 The DDR (fig. 9) is a relatively new 
 model developed for areas where a mast- 
 feed type of machine was requested. Dif- 
 ferent versions of this machine will op- 
 erate in seam heights ranging from 5 to 
 12 ft. This model uses a T-style ATRS 
 and in most cases incorporates either a 
 canopy or a safety post at the drilling 
 controls. The positioning and ATRS con- 
 trols are located at the left front 
 wheel, and the sequence of operation is 
 the same as for model DDO. 
 
 
58 
 
 FIGURE 5. - Standard model DDM. 
 
 FIGURE 6. - Model DDM with offset drill controls. 
 
59 
 
 IGURE 7. - Model DDO with T-style ATRS. 
 
 m 
 
 £ 
 
 FIGURE 8. - Model DDO with scissors-style ATRS. 
 
60 
 
 FIGURE 9.- Model DDR. 
 
 FIGURE 10. - Model HDDR with inside controls. 
 
61 
 
 The model HDDR shown in figure 10 is an 
 example of a very versatile machine de- 
 signed for mines with high coal and bad 
 rib conditions. This machine can install 
 angle bolts and rib bolts as well as a 
 conventional pattern. The drilling con- 
 trols are in a basket that rises and 
 moves with the drilling unit. The opera- 
 tor is under a canopy and is protected 
 from rib falls by the boom structure. 
 Figure 10 shows that the inch-tram and 
 ATRS controls are located at the front of 
 the machine and are accessible from ei- 
 ther operator basket. In this situation 
 the operator is not always under bolted 
 roof when setting the ATRS but is under a 
 canopy. Because of the bad rib condi- 
 tions MSHA has approved this system, and 
 we have several in operation in the West- 
 ern States. These machines all have 
 T-style ATRS systems which will operate 
 in seam heights from 6 to 16 ft. 
 
 A new version of the DDR has just been 
 developed to try a new approach to the 
 problem of accessing inside controls. In 
 this case there is a walkway through the 
 middle of the machine which allows easy 
 access to the front end and the inch-tram 
 controls located behind the ATRS mounting 
 point on the chassis. 
 
 At present Fletcher builds two models 
 of dual-head machines that are primarily 
 used to drill holes on an angle and in- 
 stall trusses. The DDJ shown in figure 
 11 uses a T-style ATRS in conjunction 
 with canopies or safety posts near the 
 drilling controls. The positioning and 
 ATRS controls are located at the left 
 front wheel along with controls for front 
 and rear lift and wagon brakes. The 
 drilling units and controls on this model 
 move in a straight line parallel to the 
 face, and one complete row of bolts may 
 be installed with each machine setup. 
 The DDJ can be designed for seam heights 
 of 4 to 8 ft. 
 
 The LDDR shown in figure 12 is a rela- 
 tively new design and is more versatile 
 than the DDJ in that the booms sump and 
 there is an extra swing function. This 
 model uses a T- or scissors-style ATRS, 
 
 and the chassis configuration is very 
 similar to that of the DDJ and DDO. This 
 model also utilizes a canopy or a safety 
 post at the drill controls, and the se- 
 quence of operations is the same as for 
 the other models with the T or scissors 
 ATRS. A floating tram cab like the one 
 on the LDDR in figure 12 is optional on 
 all our dual-head bolters to allow for 
 greater operator headroom in lower seams. 
 
 As can be seen from the previous dis- 
 cussion, the configuration of the drill- 
 ing units on our dual-head machines var- 
 ies drastically, but the roof support 
 systems and the operating sequences are 
 very similar on every model except the 
 DDM and HDDR. The machine is trammed in- 
 to the working place from the tram deck, 
 which is located at the rear of the unit 
 and covered by an approved canopy. The 
 operator then actuates a diversion valve 
 which shifts the flow of oil to the posi- 
 tioning or inch-tram controls. This pre- 
 vents accidental actuation of the tram 
 controls when the operator is at the 
 front of the machine. The operator then 
 proceeds to the positioning station and 
 moves the machine into final position for 
 installing the first row of bolts. It 
 should be noted that at this point the 
 operator is still under bolted roof. At 
 this time the operator sets the ATRS, 
 throws another diversion valve which 
 sends the flow of oil to the drilling 
 controls, and moves forward to position 
 the drill head and install the first 
 bolt. 
 
 The drilling unit swings at least 9 ft 
 and sumps at least 12 in, which allows 
 the operator to precisely pinpoint each 
 bolt location in the row without disturb- 
 ing the roof support system. For special 
 bolt patterns the sump and swing may be 
 increased and the width of the roof sup- 
 port system varied accordingly. 
 
 Retrofit of ATRS systems to Fletcher 
 dual-head machines is not a major prob- 
 lem, and at this time most of the models 
 built without roof supports have had sys- 
 tems designed for them. The principle is 
 the same as already discussed for most 
 
 ! I 
 
62 
 
 ;.,..:,:. I-V^T 'V*X'*.,-:.Ti^,: 4 ,.j 
 
 FIGURE 11. - Model DDJ with T-style ATRS. 
 
 FIGURE 12. - Model LDDR with scissors-style ATRS and floating tram cab. 
 
63 
 
 models; in most cases the only problem 
 has been developing mounting brackets for 
 some of the custom-designed units built 
 in the late 1960's. As was stated in the 
 beginning of this paper, almost all dual- 
 head machines built since mid-1973 were 
 shipped with a roof support system of 
 some type. 
 
 Although our main thrust is to iso- 
 late the ATRS from the drilling unit, we 
 have built a few units with other sys- 
 tems. Figure 13 shows a DDM with a 
 crows-foot roof support. On this unit no 
 inch tram is required because the boom 
 will sump 9 ft. A valve was mounted on 
 the boom about 5 ft behind the drillng 
 controls; from this point, the operator 
 controls the roof suport and repositions 
 
 the drilling unit 
 bolted roof. 
 
 while remaining under 
 
 Figure 14 shows a DDO with a ring-style 
 ATRS. Both of these types of roof sup- 
 ports conform to the law, but there are 
 two major problems. First, it is very 
 hard to position the drillhead with any 
 degree of accuracy, and often it takes 
 more than one try, which can be time con- 
 suming in a production cycle. Second, 
 and most important, is the fact that when 
 the boom is being moved there is no sup- 
 port at all in contact with the roof. 
 The beam system is always in contact with 
 the roof when the man is at the drilling 
 controls , and this extra edge has proved 
 to be valuable. 
 
 SINGLE-HEAD ROOF BOLTER MODELS 
 
 For our single-head machines we have 
 two types of ATRS systems — the crows foot 
 and the arm style with rocker pads. Fig- 
 ure 15 shows a crows foot roof support in 
 relation to the drill head on a mast feed 
 style machine, and figure 16 shows a lay- 
 out of a crows foot with a ring. The 
 configuration of this type of system var- 
 ies depending on the machine model, the 
 mine roof conditions, and customer input. 
 The design load rating depends on the 
 support envelope, but in most cases it 
 works out to around 11,250 lb. If this 
 type of support is used in lieu of cano- 
 pies, the arms must project at least 18 
 in in front of the drill head. The crows 
 foot is mounted on either a single or 
 double extending cylinder enclosed in a 
 shroud of telescoping square tubing, and 
 the hydraulic circuit is the same as 
 shown in figure 4. As mentioned before, 
 this system is attached to and moves with 
 the drill unit, which can cause problems. 
 
 The arm-type system of roof support is 
 used on our new model LTDO shown in fig- 
 ure 17. The arms move independently of 
 each other and are tied together only in 
 that the two hydraulic cylinders are op- 
 erated by the same valve section. This 
 feature, along with the rocker pads, al- 
 lows for maximum surface contact in un- 
 even roof. This system will also work 
 
 with a ring, but some degree of flexibil- 
 ity will be sacrificed by tying the arms 
 together. In almost all cases, both the 
 arm-style and the crows-foot roof sup- 
 ports are made of a high-strength alloy 
 steel with a minimum yield of 100,000 
 psi to achieve a reasonable weight-to- 
 strength ratio. The drilling unit of the 
 LTDO is independent of the arms , and it 
 is able to sump 8 in and swing 3 in to 
 each side of center. This feature allows 
 for accurate bolt location without dis- 
 turbing the roof support. The LTDO in 
 figure 18 also has a canopy incorporated 
 into the rocker of the ATRS. 
 
 The model DB machine is different from 
 the LTDO only in that it uses a mast feed 
 for the drill head instead of an arm 
 feed and a crows-foot rather than an arm- 
 type ATRS. Both the LTDO and DB have the 
 inch-tram and ATRS controls between the 
 wheels and a tram deck with canopy at the 
 rear of the machine. In both cases, ei- 
 ther a stab jack or stab foot is included 
 and is considered a part of the support 
 system. A floating tram cab for low 
 seams is also available on model LTDO 
 and DB machines. 
 
 To date, we have not built a single- 
 head machine that can install more than 
 one bolt on a regular pattern with a 
 
64 
 
 FIGURE 13. - Model DDM with crows-foot ATRS. 
 
 FIGURE 14. - Model DDO with ring-style ATRS. 
 
65 
 
 Crows foot ATRS 
 
 Drillhead 
 
 FIGURE 15. - Crows-foot ATRS on drill mast. 
 
 single ATRS setup; however, we have de- 
 signed a few single-head machines that 
 could do this. In most cases a dual-head 
 machine is much more practical from a 
 cost benefit standpoint than a single- 
 head unit, and for this reason, we have 
 not emphasized the single-head, multiple- 
 bolt machine. 
 
 Retrofit kits have been developed for 
 most of our single-head units using ei- 
 ther a crows-foot or an arm-style ATRS. 
 Since most of these old machines do not 
 have swinging or sumping booms , the roof 
 support and the drill head are usually 
 not independent of each other. Another 
 factor that must be taken into considera- 
 tion on older machines is tram canopies. 
 Most of these machines did not have tram 
 decks at the rear when they were origi- 
 nally built, so a tram canopy must be 
 added to comply with MSHA requirements 
 when they are modified. Fletcher has de- 
 veloped a few kits for some of our LTDO's 
 
 Ring assembly 
 
 Snubber 30321 pin 
 
 mffim 
 
 o oi 
 o oi 
 
 i o o 
 
 'o o 
 
 SECTION A-A' 
 
 Z Z Z jfl 
 
 1 mi 
 
 - t -n - iinl 
 
 — -U. JU —it™ 
 
 r- 1 — i inn 
 
 i_ i_ .in 
 
 _q_ _i i 
 i mi 
 
 i 
 
 ELEVATION 
 
 FIGURE 16. - Crows-foot ATRS with ring. 
 
66 
 
 FIGURE 17. - Model LTDO with arm-style ATRS. 
 
 FIGURE 18. - Model LTDO with drilling canopy on ATRS rocker pad, 
 
67 
 
 FIGURE 19. - Model DB with retrofitted crows-foot ATRS. 
 
 FIGURE 20. - Stand-alone or satellite ATRS system on a model DO. 
 
68 
 
 and DB's, but the cost and time involved 
 were excessive and in the end we had a 
 machine that was too cumbersome to be 
 practical in a production cycle. It also 
 should be remembered that most of the 
 frames and drive systems on these old 
 units were not designed to carry the 
 increased weight encountered when adding 
 a roof support and tram deck. A crows- 
 foot ATRS can be added fairly easily to 
 a machine that already has a rear tram 
 deck, but reduced flexibility makes it 
 very hard to use a machine of this type 
 in a production cycle. Figure 19 is an 
 
 example of a retrofit of a crows foot on 
 a model DB drill. 
 
 We tried a stand-alone, or satellite, 
 ATRS system on a single-head model DO 
 roof drill (fig. 20) in 1973 but set the 
 concept aside because we felt that the 
 possibilty of knocking the support posts 
 out with the machine was too great. The 
 ATRS unit contained two cross members; 
 unlike satellite systems developed by 
 others, our ATRS was carried with a pair 
 of extra lifting arms instead of the 
 drill head. 
 
 RETROFIT AND REBUILD PROCEDURES 
 
 After careful consideration and some 
 cost studies of existing retrofit proj- 
 ects, we feel that in many cases the 
 most practical thing to do is salvage the 
 parts and install them on a new chassis, 
 with a rear tram deck and an arm-style 
 ATRS. Many of the components such as 
 wheel hubs , drive motors , drill heads , 
 and valves can be reused, and in most 
 cases all of the cylinders and electrical 
 components will adapt. In all cases a 
 new chassis would be designed to adapt to 
 as many of the old components as pos- 
 sible, and the drill unit would be in- 
 stalled on a boom that swings and sumps. 
 We feel that this can be done for a rela- 
 tively small additional cost, and in the 
 
 end the customer will have a machine that 
 Is much more practical from a production 
 standpoint. Increased productivity could 
 very well offset the increased cost of 
 the new chassis and boom. 
 
 This may not be the best solution, how- 
 ever, if the machine is going to be used 
 only for utility bolting. Since the lo- 
 cation of the bolt will not be critical, 
 a crows-foot kit or a good canopy may be 
 the best solution. Each situation must 
 be studied, and the best solution will 
 depend on how the machine is going to be 
 used, the conditions in which it will be 
 required to operate, and the overall con- 
 dition of the machine in question. 
 
69 
 
 ATRS SYSTEMS FOR LEE-NORSE ROOF BOLTERS 
 By Guido Bucelluni 1 
 
 INTRODUCTION 
 
 Several of the papers presented ear- 
 lier in this meeting discussed the tech- 
 nical aspects of ATRS systems in general 
 and the requirements of existing ATRS 
 
 regulations. Therefore, this paper will 
 discuss only Lee-Norse bolting machines 
 and the ATRS systems designed for them. 
 
 GENERAL FEATURES 
 
 All ring-type or support-arm ATRS sys- 
 tems for Lee-Norse bolters contain all 
 design features needed to meet ATRS and 
 "in lieu of canopy" regulations (pilot 
 check valves, streamlined controls, load- 
 carrying capability, etc.). The config- 
 uration of the roof support ring on Lee- 
 Norse bolters can vary from round to 
 hexagonal to rectangular, but all such 
 structures extend 6 in inby the drill 
 chuck. The support arm hydraulic system 
 is designed to automatically maintain a 
 factory-determined upward thrust of 1,500 
 to 2,000 lb on the roof support struc- 
 ture. Most Lee-Norse bolter models con- 
 tain a sumping drill box (8-in range of 
 travel) to compensate for drill chuck 
 misalignment when the support arm is in 
 place. This feature allows the operator 
 to locate the drill hole precisely with- 
 out moving the entire ATRS system. All 
 
 design features of the support-arm system 
 can be retrofitted to machines in the 
 field. 
 
 Although the support arm ATRS system 
 alone is sufficient to meet all ATRS re- 
 quirements, some customers also desire 
 the additional protection of an out- 
 front, bar-type ATRS structure. For this 
 reason, Lee-Norse offers two types of 
 bar-type structures, the dolly-bar and 
 the T-bar designs, as optional or retro- 
 fit equipment on all dual-head bolters. 
 The dolly bar has a collapsed height of 
 23 in and requires 4 to 7 s to reach its 
 maximum extended height of 93 in. The 
 T-bar has a more limited height range (51 
 in to 10 ft) , but has a sump range of 54 
 in. When the sumping jack is fully re- 
 tracted, the T-bar fits easily between 
 the support arms of the dual-boom bolter. 
 
 SINGLE-HEAD BOLTERS 
 
 Figure 1 shows the TD 1-24/ 2 7 model roof 
 bolter (frame height 24 to 27 in), and 
 figure 2 shows the TD1-29/31 model (frame 
 height 29 to 31 in). Both models contain 
 support-arm ATRS systems with streamlined 
 inch-tram stations. One major difference 
 between the two models is that the 
 
 1 Product manager, roof bolters, 
 Norse Co., Pittsburgh, PA. 
 
 Lee- 
 
 TD1-29/31 has a cantilevered, "elephant 
 ear" canopy over the drilling-bolting 
 station, whereas the TD1-24/27 does not. 
 The other major difference is that the 
 tramming deck and canopy are located on 
 the left rear corner of the TD1-29/31; 
 on the TD1-24/27 these items are located 
 farther forward, adjacent to the left 
 tram wheels. 
 
70 
 
 FIGURE 1. - Low-coal, single-head, TD1-24/27 roof bolter with safety-arm ATRS. 
 
 DUAL-HEAD BOLTERS 
 
 Lee-Norse manufactures three basic 
 models of dual-head roof bolters — the 
 TD2-30/34 (figs. 3-4), the TD2-43 (figs. 
 5-6), and the TD-12 (fig. 7). Figure 3 
 shows the TD2-30/34 with support arms 
 only; figure 4 shows the same machine 
 with a dolly-bar ATRS system in addition 
 to the support arms. Note in figure 3 
 that the tramming deck and canopy are lo- 
 cated between the tires on the right side 
 of the machine. 
 
 The TD2-43 (figs. 5-6) is a slightly 
 larger machine (support arms reach 10 ft 
 high) , but its tram station is basical- 
 ly the same as the one on the TD2-30/ 
 34. The major differences between the 
 machines in figures 5 and 6 are (1) the 
 TD2-43 in figure 5 has round roof support 
 rings and a dolly-bar ATRS beam and 
 
 (2) the TD2-43 in figure 6 has rectangu- 
 lar roof support rings and a T-bar ATRS 
 beam. 
 
 Figure 7 shows the mast-type TD-12 
 bolter, designed for situations where an- 
 gle bolting is required (roof trusses, 
 rib bolts, etc.). When used for vertical 
 drilling, the posts and canopies above 
 the drilling-bolting stations are suffi- 
 cient to meet all applicable regulations; 
 the out-front dolly bar is an optional 
 feature. Since truss and rib bolts are 
 usually installed under supported roof , 
 only canopy laws apply, so the TD-12 ma- 
 chine is sufficient for this purpose. 
 The out-front dolly bar (or T-bar) may be 
 required if angle drilling is conducted 
 in areas of unsupported roof . 
 
71 
 
 FIGURE 2. - Single-head TD1-29/31 roof bolter with safety-arm ATRS and cantilevered drilling 
 canopy. 
 
 .•■"•""•""""""dfc 
 
 FIGURE 3. - Dual-head TD2-30/34 roof bolter with safety-arm ATRS. 
 
72 
 
 FIGURE 4. - TD2-30/34 roof bolter with dolly-bar and safety-arm ATRS. 
 
 FIGURE 5. - Dual-head TD2-43 roof bolter with dolly-bar ATRS. 
 
73 
 
 FIGURE 6. - TD2-43 roof bolter with T=bar ATRS. 
 
 FIGURE 7. - Mast=type TD-12 roof bolter for angle bolting. 
 
74 
 
 LONG-AIRDOX ATRS SYSTEMS FOR ROOF BOLTERS 
 By C. L. Bandy, Jr., 1 and David L. Phillips 2 
 
 INTRODUCTION 
 
 Long-Airdox Co. has been a manufacturer 
 of roof bolting machines for over 20 yr. 
 In view of this , it is easy to understand 
 that Long-Airdox has a vested interest in 
 safety systems for roof bolting machines. 
 Subsequently, a series of ATRS systems 
 have been developed and integrated into 
 their product lines. 
 
 Although presently West Virginia and 
 Virginia are the only States to mandate 
 the use of ATRS systems, Long-Airdox 
 feels that such systems used on bolting 
 machines are effective tools for protect- 
 ing miners during the installation of 
 permanent supports. Together with pro- 
 viding protection for miners, substantial 
 time savings in bolter turnaround time 
 have been realized, thus enhancing their 
 use. 
 
 'Director, field service training, 
 Long-Airdox Co., Oak Hill, WV. 
 
 2 Project engineer, roof bolters, Long- 
 Airdox Co., Oak Hill, WV. 
 
 NEW MACHINE DESIGNS 
 
 Long-Airdox Co. offers a wide range of 
 roof bolting machines to work in low, 
 medium, and high seams. 
 
 LRB-25 For Low Seams 
 
 Figure 1 shows an LRB-25 roof bolter 
 designed for low-seam operation. As 
 shown, the LRB-25 is equipped with a 
 mast-type ATRS with a single-beam load 
 frame. The ATRS load certification is 
 for 22,500 lb. The ATRS has a hydrauli- 
 cally actuated stroke of 12 in with a 
 nominal base specified from 22 to 34 in. 
 Overall height may be adjusted upward (in 
 2-in increments) an additional 6 in. As 
 shown in figure 1, the ATRS remains at- 
 tached to the bolter and can be raised up 
 with 5 in of ground clearance and remain 
 22 in in overall height. Once the ATRS 
 is set, it acts as a stabilizer, thus 
 permitting the bolter to be backed away 
 approximately 14 in, allowing clear 
 
 FIGURE 1. ° LRB-25 for low seam with single=beam mast-type ATRS. 
 
75 
 
 access for installing bent bolts. The 
 LRB-25 measures 24 in high (with 4-in 
 ground clearance) by 44 in wide by 11 ft 
 9 in long and weighs 4,400 lb. 
 
 LRB-15AR For Low to Medium Seams 
 
 Figure 2 shows a model LRB-15AR roof 
 bolter equipped with a safety-arm- type 
 ATRS. The ATRS ranges from 30 in minimum 
 to 76-5/8 in maximum (6-in ground clear- 
 ance) and is load certified at 11,250 lb. 
 Maximum range is 82-5/8 in with 12-in 
 ground clearance. An opening measuring 
 21 in wide by 32 in long is provided in 
 the ATRS for ease of bolting. The LRB- 
 15AR measures 27 in high by 74 in wide by 
 14 ft 10 in long (with 6-in ground clear- 
 ance) and weighs 12,000 lb. 
 
 LRB-16 for Medium to High Seams 
 
 Figure 3 illustrates the LRB-16 roof 
 bolter, which is furnished with a single- 
 safety-arm type ATRS. The ATRS ranges 
 from 50-1/2 in mimimum to 120 in maximum 
 (with 18-in ground clearance) and is load 
 certified at 11,250 lb. Minimum range is 
 
 42-1/2 in with 10-in ground clearance. 
 An opening is provided in the ATRS head 
 measuring 27-1/2 in by 30 in to ease the 
 bolting operation. The LRB-16 overall 
 dimensions are 50 in high (18-in ground 
 clearance) by 80-1/2 in wide by 19 ft 
 
 4 in long, and it weighs 18,200 lb. 
 
 LRB-23 for Medium to High Seams 
 
 Figure 4 pictures a Long-Airdox LRB-23 
 dual-arm roof bolting machine with a 
 mast- type H-beam load frame ATRS cer- 
 tified at 67,500 lb. This model is 
 also available with a mast-type ATRS 
 with single-beam load frame certified at 
 33,750 lb. ATRS range is specified from 
 48 in minimum to 14 ft in maximum. 
 ATRS width is adjustable from 8 ft in 
 to 10 ft in. The ATRS is provided with 
 a 7 ft in nominal sump, thus allowing 
 for two rows of bolts using standard cen- 
 ters. The H-beam ATRS design provides 
 
 5 ft in between load frames. Basic ma- 
 chine dimensions for the LRB-23 are 48 in 
 high (12 in ground clearance) by 9 ft 2 
 in wide by 20 ft 4-3/8 in long. Weight 
 is approximately 46,100 lb. 
 
 FIGURE 2. . LRB-15AR with safety-arm ATRS. 
 
76 
 
 FIGURE 3. - LRB-16 with safety-arm ATRS. 
 
 FIGURE 4. - LRB-23 with mast-type H-beam ATRS. 
 
 RETROFITTING 
 
 Along with designing ATRS systems for 
 new roof bolting machines, Long-Airdox 
 has an ongoing program of design to fit 
 existing units with ATRS systems. Two 
 existing Long-Airdox roof bolters (LRB-15 
 and LRB-15A) have conversion kits avail- 
 able from the factory, as follows: 
 
 LRB-15A conversion to safety-arm-type 
 ARTS 
 
 1. Complete inch-tram system. 
 
 2. Relocation of ATRS controls to a 
 point where they will be under permanent- 
 ly supported roof during setup. 
 
77 
 
 3. Complete ATRS system as per LRB- 
 15AR design (not mandatory if unit was 
 equipped from factory with roof support 
 system) . 
 
 LRB^15 conversion to mast-type 
 H-beam load frame ATRS 
 
 3. Complete inch-tram system. 
 
 4. Unit is fitted with a mast-type 
 ATRS. Some units were originally sup- 
 plied with a canopy from the factory. If 
 so, this canopy is removed and bolter is 
 then fitted with ATRS. 
 
 1. Relocation of tram compartment from 
 front to rear of unit. 
 
 2. General 
 components. 
 
 rearrangement of internal 
 
 5. ATRS controls are located where 
 they will be under permanently supported 
 roof during setup. 
 
 CONCLUSION 
 
 Since the early 1960's, Long-Airdox has 
 been actively engaged in the design of 
 roof bolting machines. Functional ATRS 
 
 systems have evolved and been accepted as 
 viable protective devices for mine per- 
 sonnel during the bolting operation. 
 
 aU.S. CPO: 1984-505-019/5081* 
 
 INT.-BU.OF MINES, PGH., PA. 27752 
 
«. 30? 85 
 
 
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