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BUREAU OF MINES ^5^ 
 INFORMATION CIRCULAR/1988 
 
 Integrated Compartment-Machine 
 Design for Low-Coal Shuttle Cars 
 
 By John R. Battels, August J. Kwitowski, 
 and William D. Mayercheck 
 
 UNITED STATES DEPARTMENT OF THE INTERIOR 
 
Information Circular 9200 
 
 Integrated Compartment-Machine 
 Design for Low-Coal Shuttle Cars 
 
 By John R. Bartels, August J. Kwitowski, 
 and William D. Mayercheck 
 
 UNITED STATES DEPARTMENT OF THE INTERIOR 
 Donald Paul Hodel, Secretary 
 
 BUREAU OF MINES 
 T S Ary, Director 
 

 Library of Congress Cataloging in Publication Data: 
 
 Bartels, John R. 
 
 Integrated compartment-machine design for low-coal shuttle cars. 
 
 (Information circular; 9200) 
 
 Bibliography: p. 18 
 
 Supt. of Docs, no.: 128.27:9200. 
 
 1. Mine railroads -Cars -Safety measures. 
 
 I. Kwitowski, August J. II. Mayercheck, William D. III. Title. IV. Series: 
 Information circular (United States. Bureau of Mines); 9200. 
 
 TN295.U4 [TN342] 
 
 622 s 
 
 [622'. 334] 88-600147 
 
CONTENTS 
 
 Page 
 
 Abstract 1 
 
 Introduction 2 
 
 Project execution 2 
 
 Evaluation criteria 2 
 
 Cab-shuttle car concepts 3 
 
 Determination of remote vision limitations 4 
 
 Discussion of concepts 4 
 
 Design considerations 10 
 
 Design procedure 13 
 
 Mockup and evaluation 16 
 
 Changes resulting from mockup 17 
 
 Conclusions 18 
 
 References 19 
 
 ILLUSTRATIONS 
 
 1. Parallel end-driven shuttle car 5 
 
 2. Parallel center-driven shuttle car 6 
 
 3. Transverse end-driven shuttle car 7 
 
 4. Bottom dump shuttle car 8 
 
 5. Transversely mounted end-cab 9 
 
 6. Vision-assist test 11 
 
 7. Coal miner anthropometrics 12 
 
 8. Compartment design 13 
 
 9. Control layouts 14 
 
 10. Selected control layout 15 
 
 11. Computer-generated field of vision 15 
 
 12. Shuttle car operator seat 16 
 
 13. Joystick steering 17 
 
 14. Final mockup 18 
 
 TABLE 
 
 1. Recommended control motions 12 
 
UNIT OF MEASURE ABBREVIATIONS USED IN THIS REPORT 
 
 ft 
 
 foot 
 
 pet 
 
 percent 
 
 h 
 
 hour 
 
 y 
 
 year 
 
 in 
 
 inch 
 
 
 
INTEGRATED COMPARTMENT-MACHINE DESIGN FOR LOW-COAL 
 
 SHUTTLE CARS 
 
 By John R. Bartels, 1 August J. Kwitowski, 1 and William D. Mayercheck 2 
 
 ABSTRACT 
 
 This Bureau of Mines report describes the development of a preliminary design for a novel, protected, 
 cab-shuttle car for use in working seam heights down to 40 in. Because of the severe restrictions 
 imposed by low-coal operation, Mine Safety and Health Administration (MSHA) regulations only require 
 canopy protection on shuttle cars operating in seam heights of 42 in or greater. MSHA routinely grants 
 variances for canopy use in seams 48 in high or less. The design was generated by giving the operator 
 needs equal priority as related to machine performance parameters. Cab-shuttle car concepts that led 
 to the recommended design are described, along with criteria and testing used to evaluate their potential 
 effectiveness. 
 
 Civil engineer. 
 
 Supervisory physical scientist. 
 
 Pittsburgh Research Center, Bureau of Mines, Pittsburgh, PA. 
 
INTRODUCTION 
 
 Cabs and canopies installed on underground coal 
 mining face equipment in use on high-coal equipment have 
 established an impressive record of preventing fatal and 
 nonfatal operator injuries. MSHA estimates that from 
 January 1974 through December 1985, the protective 
 structures kept 233 lives from being lost as a result of roof 
 falls (2). 3 Unfortunately, the successful application of cabs 
 and canopies has occurred almost exclusively in relatively 
 high coal seams. A 1982 survey showed that for working 
 heights below 48 in, only 27 pet of all face equipment had 
 protective operator structures. For working heights below 
 42 in, the percentage of equipment with cabs and canopies 
 dropped to 2 pet (3). 
 
 While the availability of protection in working heights 
 below 48 in is low, the need for protection is high. For the 
 2 yr period 1980 through 1981, there were a total of 2,212 
 fatal and nonfatal equipment accidents in working heights 
 below 48 in. It was estimated that 71 pet of these 
 accidents could have been prevented had protective 
 structures been employed (3). 
 
 A problem with trying to provide workable cabs and 
 canopies for face equipment used in seam heights below 
 48 in relates to simple geometry. Insufficient space exists 
 to (1) have the machine perform its intended functions, 
 (2) station an operator and the controls, (3) insure 
 adequate operator vision to key points on the machine and 
 in the mine, (4) provide sufficient operator comfort for 
 
 protracted work periods, and (5) provide structures that 
 both protect the operator and do not significantly interfere 
 with other requirements. The issue of protecting shuttle 
 car operators from hazards becomes increasingly difficult 
 with decreasing working height. 
 
 Underground face equipment, such as continuous 
 miners, roof bolters, face drills, etc., is usually much easier 
 to equip with protective operator cabs than shuttle cars. 
 These types of face equipment perform their functions 
 primarily at one location; e.g., a continuous miner extracts 
 coal at the face, while, because of its function, a shuttle car 
 frequently travels through the working section. The tram 
 rates of shuttle cars are also significantly higher than those 
 of other face equipment. Current shuttle car designs tend 
 to maximize tram clearances for tight spots in mine 
 workings. 
 
 The requirement for tram clearance is opposed by a 
 primary goal in the shuttle car design - maximize the 
 amount of cut coal transported from the face. An 
 unfortunate effect is that space that should be used for 
 operator, the controls, and a protective structure is 
 sacrificed for increased coal capacity and tram clearance. 
 Classic shuttle car design philosophy has provided for 
 operator needs as a secondary consideration, which 
 partially explains the limited success achieved over decades 
 in developing adequate protective cabs for thin-seam 
 shuttle cars. 
 
 PROJECT EXECUTION 
 
 The failure of past design methods to produce adequate 
 thin-seam shuttle car cabs required that a fresh approach 
 be taken. Thus, the objective of this project was to 
 develop an acceptable cab-shuttle car design by giving the 
 operator's needs equal priority as related to classic design 
 criteria. Although the resulting design could have 
 diminished performance specifications compared with 
 present designs, a suitable compromise was achieved 
 among operator safety, coal-carrying capacity, and 
 maneuverability. 
 
 A wide variety of ideas and influences were considered 
 to generate cab-shuttle car concepts and guide the 
 
 progression of the project. Therefore, a project advisory 
 committee was formed of Bureau and MSHA personnel. 
 MSHA participation ensured contributions to the project 
 and updated the agency on developments of interest. 
 
 The advisory committee functions were to formulate 
 criteria for evaluating the acceptability of cab-shuttle car 
 concepts; conceive cab-shuttle car concepts; evaluate, 
 refine, and eliminate concepts; and make recommendations 
 for future project efforts. 
 
 EVALUATION CRITERIA 
 
 An initial task was the formulation of criteria for 
 gauging the acceptability of cab-shuttle car concepts. Two 
 classes of criteria were developed: those considered 
 mandatory—not meeting them would cause a concept to be 
 rejected outright; and those considered desirable-concepts 
 including them would be ranked higher than those that did 
 not. 
 
 Italic numbers in parentheses refer to items in the list of references 
 at the end of this report. 
 
 Mandatory criteria were 
 
 1. The cab should employ protective operator 
 structures; this includes protection from ground falls and 
 the minimization of pinching and squeezing-type accidents, 
 which are the most common in thin-seam shuttle car 
 haulage (3). 
 
 2. The cab-shuttle car should be maneuverable in 
 workings having typical dimensions for thin-seam room- 
 and-pillar mining. 
 
3. The operator should have adequate field of vision to 
 key points on the machine and in the mine. 
 
 4. The operator should be provided a comfortable 
 working position. 
 
 5. Other section workers should not be endangered by 
 haulage vehicle operation. 
 
 6. Cab ingress and egress should be reasonable. 
 
 7. The cab-shuttle car should be usable in working 
 heights down to 40 in. 
 
 The decision was made to target a 40-in working height 
 for the cab-shuttle car design, based on the following 
 factors: 
 
 A. For the development to be viewed as significant, it 
 should be applicable below the current 42-in limit where 
 Federal regulations mandate cabs and canopies. 
 
 B. Present industry practice considers 36-in working 
 heights as the low cutoff point for batch-type haulage; 
 lower height mines generally use continuous haulage. 
 
 C. Previous studies showed a general dislike for low- 
 height operating positions other than the semireclined, 
 which is usable down to about 40 in for high-speed face 
 equipment (4). 
 
 D. The development effort could be approached with a 
 reasonable degree of confidence for a successful outcome. 
 
 Desirable criteria included 
 
 1. Ideally the operator should not be required to 
 change seat positions depending upon the travel direction. 
 In low working heights, changing seats is currently the only 
 successful method of obtaining vision in both travel 
 
 directions. However, the procedure is cumbersome, 
 awkward, time consuming, and exposes the operator to 
 additional hazards. 
 
 2. Cab concepts should be as compatible as possible 
 with commercially available shuttle cars. 
 
 3. Cab concepts should be adaptable to haulage 
 vehicles other than shuttle cars. 
 
 4. Electronic sensory aids should be employed, but 
 kept as simple as possible. For example, a closed-circuit 
 television system (CCTS) could provide information on 
 blind spots not within the operator's line of sight. 
 
 5. The operator should be provided an indication of 
 obstacles in the vehicle path. 
 
 6. For cab designs where it is necessary for the 
 operator to change seat positions according to the travel 
 direction, the controls should be miniaturized to the point 
 of being a hand-held module. The module should be 
 connected to machine actuators through either a tethered 
 or radio remote control link. This would eliminate the 
 need for two separate control panels. 
 
 7. The resulting design should be cost effective. 
 
 8. The controls and cab layout should give the operator 
 a feeling of confidence, allow easy operation, and provide 
 a natural control sequence. 
 
 9. The complexity of the design should be minimized 
 to reduce maintenance frequency. 
 
 10. Floating cabs should be utilized. Past Bureau 
 projects (2, 3-4) indicated that floating cabs generally 
 provide more operator space than traditional fixed cabs. 
 
 CAB-SHUTTLE CAR CONCEPTS 
 
 Cab-shuttle car concepts were generated at monthly 
 meetings held by the advisory committee, and were quickly 
 critiqued through open discussions. Those concepts that 
 survived the oral discussion stage were translated into 
 sketches and/or scale drawings. Most drawings referenced 
 concepts to the outline of a National Mine Service* model 
 MC28 shuttle car in a typical 40-in working height entry; 
 this was considered typical of the 1,839 shuttle cars 
 currently in use in coal seams under 48 in. At subsequent 
 meetings, the concepts underwent further evaluation, 
 discussion, and refinement. Many concepts were 
 eliminated through this process; other new ideas were 
 conceived and entered the system. 
 
 The generated concepts fell into five general cab-shuttle 
 car configuration: 
 
 Reference to specific products does not imply endorsement by the 
 Bureau of Mines. 
 
 1. Traverse, center-driven cab: The operator cab is 
 situated perpendicular to the longitudinal axis of the 
 haulage vehicle, midway between its ends. An advantage 
 is that the operator would not have to change seat 
 positions when the travel direction changes. Disadvantages 
 include that the cab would decrease the coal-carrying 
 capacity and the operator would not have excellent field of 
 vision in either direction of travel. 
 
 2. Parallel, end-driven cab: The operator cab is situated 
 parallel to the longitudinal axis of the haulage vehicle, 
 close to one end of the machine. Assuming the operator 
 changes seat positions depending on travel direction, this 
 configuration would provide the operator with very good 
 direct vision in one travel direction, but poor direct vision 
 in the opposite direction. Assuming the operator remains 
 in one seat position for both travel directions an 
 
automated steering system or the ability to steer the 
 vehicle from sensory input devices would be required. 
 
 3. Parallel, center-driven cab: The operator cab is 
 situated parallel to the longitudinal axis of the haulage 
 vehicle, midway between its ends. Assuming that the 
 operator changes seat positions with travel direction and 
 the cab width could be approximately 10 in greater than a 
 standard cab, visibility along the side of the machine could 
 be adequate, but somewhat impeded by machinery in the 
 field of view. When considering a design where the 
 operator sits in only one position, direct visibility in one 
 travel direction would be nonexistent, requiring the 
 addition of remote sensory and/or automated steering 
 systems. 
 
 4. Transverse, end-driven cab: The operator cab is 
 positioned at an end of the vehicle, perpendicular to the 
 
 longitudinal axis of the machine. An advantage is that the 
 operator would have extremely good field of vision when 
 tramming to the dump site and restricted, but adequate, 
 field of vision in the opposite tram direction. Perceived 
 problems included a significant loss of coal-carrying 
 capacity, potential roofing-out problems, and the cab and 
 chain conveyor mechanism competing for the same space. 
 
 5. Cross-car, end-mounted cab: The operator is 
 positioned across the end of the vehicle, perpendicular to 
 the longitudinal axis of the chain conveyor. This 
 arrangement would give the operator unobstructed vision 
 when tramming to the dump site and very good vision 
 down the empty conveyor when tramming to the face. The 
 main disadvantage appeared to be increased complexity of 
 operation when unloading coal. 
 
 DETERMINATION OF REMOTE VISION LIMITATIONS 
 
 The committee initially considered cab-shuttle car 
 concepts using conventional parallel, center-driven and 
 parallel, end-driven cab placements. Exploration of these 
 concepts readily revealed a primary objection to the use of 
 protective cabs in low coal - the problem of direct operator 
 vision to key reference points. 
 
 If the desirable feature of maintaining the operator in 
 one seat position is assumed, both versions of parallel cabs 
 considered do not allow the operator direct vision in one 
 travel direction. A simple CCTS was proposed to provide 
 the operator with visual input from the blind travel 
 direction. 
 
 A quick experiment was conducted to estimate an 
 operator's ability to steer a vehicle using only CCTS vision. 
 The experiment utilized available closed-circuit video 
 equipment and a battery-powered vehicle; it took place on 
 vacant roadways at the Bureau's Pittsburgh {PA) Research 
 Center. A camera transmitted a forward view, in the 
 travel direction, to a video monitor placed in front of the 
 driver. A shroud prevented direct forward vision. Five 
 different drivers attempted to negotiate straight and curved 
 road sections using only visual information from the 
 monitor. The results of the experiment were not 
 favorable. The consensus was that satisfactory movement 
 
 in a desired path required great concentration and could 
 be achieved only if an object was present to sight along, 
 such as a curb. Poor performance using the video system 
 was attributed to the lack of depth perception and 
 differences in field and angle of view between a person's 
 eyes and the camera lens. 
 
 This experiment was conducted with the drivers trying 
 to maneuver the vehicle while facing the travel direction. 
 For the concept to be usable with the cabs, the operator 
 would need to maneuver the vehicle while facing in the 
 direction opposite of travel, further decreasing the 
 likelihood of success. 
 
 The negative experiment results led to the following 
 conclusions on design options related to parallel-oriented 
 cabs: 
 
 1. The operator must switch seat positions, depending 
 upon travel direction, which is undesirable. 
 
 2. If the same seat position is maintained, steering the 
 vehicle in one travel direction requires additional sensory 
 input to supplement televised views, such as obstacle 
 detectors, and distance-alignment sensors, and/or that an 
 automatic or semiautomatic steering system be employed. 
 
 DISCUSSION OF CONCEPTS 
 
 Although the cross-car, end-mounted cab configuration 
 initially appeared to present inherent, insurmountable 
 problems, a variation of it was ultimately selected for the 
 recommended cab-shuttle car design. The following 
 discussion details specific ideas considered for the five 
 general cab-shuttle car configurations, reasons for 
 dismissing or not selecting the concepts, and the 
 preliminary design of the selected configuration. 
 
 1. Transverse, center-driven cab: This configuration 
 was successful on a shuttle car used in high seams (5) and 
 initially appeared promising for thin-seam application. 
 
 However, drawing the concept to scale revealed there was 
 insufficient vertical space for it to be used in a 40-in 
 working height. The basic problem was that the operator's 
 feet must extend under the conveyor, using 18 in of vertical 
 space, and the remaining space was insufficient for the 
 conveyor and machine-to-roof clearances. The concept 
 was eliminated on these grounds. 
 
 2. Parallel, end-driven cab: Two concepts were 
 proposed and evaluated for this cab-shuttle car 
 configuration: A, the operator changing seat positions 
 
■ 307 " 
 
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 108 
 
 Control case 
 
 89"- 
 
 Tram motor 
 
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 22" 
 
 i*-2i"--H * 
 
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 36" 
 
 42"- 
 
 Pump motor 
 
 Tram motor 
 
 L I2" 
 
 _*, £_ 
 
 Xf 
 
 W 
 
 v- 
 
 V 
 
 _*L 
 
 92" 
 
 J£ 
 
 FIGURE 1. -Parallel end-driven shuttle car. 
 
 depending on travel direction (fig. 1), and B, the operator 
 maintaining one seat position. 
 
 A. The first concept would provide the operator 
 with very good direct vision in the travel direction away 
 from the machine. Travel in the opposite direction would 
 require major changes to the classical layout of shuttle car 
 subsystems for increased direct vision and probably 
 necessitate that CCTS's be employed to provide views to 
 blind spots. 
 
 B. Because of the results of the remote vision 
 experiment, the second concept would require additional 
 sensory input supplement televised views and/or an 
 automatic or semiautomatic steering system. As neither 
 concept appeared particularly attractive, they were not 
 taken beyond the discussion stage. 
 
 3. Parallel, center-driven cab: The center-driven 
 concepts (fig. 2) did not impose length restrictions on the 
 cab, thus providing the potential for maximum operator 
 comfort. Two concepts on opposite ends of the 
 technological spectrum were considered for this cab-shuttle 
 car configuration. 
 
 A. The low-technology concept required that (1) the 
 operator switch seat positions depending on the travel 
 direction, (2) the cab width be approximately 10 in greater 
 than current practice, (3) the normal layout of vehicle 
 subsystems undergo significant changes to increase 
 operator visibility, and (4) CCTS's be employed to improve 
 visibility of otherwise blind areas. It was decided not to 
 proceed with the development of this cab as it met few of 
 
 the desired design criteria and did not appear applicable 
 to a large cross section of the haulage vehicle population. 
 
 B. The high- technology cab concept included the 
 following design features: 
 
 1. The operator would sit in one position only, 
 regardless of travel direction, and be provided a positive 
 indication of the current tram direction. 
 
 2. It would be a generic box, adaptable to a 
 wide range of currently manufactured haulage vehicles. 
 
 3. An updated version of the automatic steering 
 technology developed by the Bureau would be employed 
 (6). This subsystem would output to a display of the 
 vehicle's position relative to idealized paths for both 
 straightaway tramming and the turning of crosscuts. The 
 steering system could be placed in either manual or 
 automatic mode. 
 
 4. Wide-angle-view CCTS's would be used, 
 providing the operator with views of obstacles in the 
 vehicle path. 
 
 5. Electronic rangefinder units would be placed 
 on both ends of the vehicle and would output to a cab 
 display the distances between the vehicle and objects in the 
 vehicle path. 
 
 6. If possible, machine controls would be 
 designed to be detachable from the body of the haulage 
 vehicle. During emergency situations, this would allow 
 remote, within-sight control. 
 
no 
 
 -307 
 
 ■ 50" »T« 60"- 
 
 Cable reel 
 
 108- 
 
 Conveyor motor 
 
 Control case 
 
 89- 
 
 Tram motor 
 
 Pump motor 
 
 32" 
 
 -67"- 
 
 Tram motor 
 
 * * * »y ■#. a 
 
 92 
 
 43" 
 
 
 FIGURE 2.-Parallel center-driven shuttle car. 
 
 The concept met many of the desired criteria including 
 the capability of being placed on many currently 
 manufactured haulage vehicles or completely new designs. 
 
 Concept disadvantages included that it would be 
 electronically complex, requiring an updated version of the 
 automatic-steering technology, wide-angle-view CCTS's to 
 provide the operator views of obstacles in the vehicle path, 
 and electronic rangefinder units to indicate distances to 
 objects. However, the main concern was the unproven 
 ability of an operator to maneuver the machine, with no 
 direct vision, when traveling in the direction opposite from 
 the faced position. 
 
 It was concluded that although the high-technology 
 concept did offer merit, it would be best pursued as a 
 separate, future project. 
 
 4. Transverse, end-driven cab: This concept (fig. 3) 
 worked well on higher seam vehicles because the operator 
 was able to tram in both directions without changing seat 
 positions. However, this configuration posed several 
 serious problems for low-seam applications: 
 
 1. The coal-carrying capacity of the shuttle car 
 would be decreased because the operator's legs require 
 18 in of space under the conveyor; and, compared to 
 conventional design, the cab would extend an additional 
 10 in beyond the machine frame, requiring narrower cars 
 for adequate maneuverability. 
 
 2. Field would be poor when tramming to the 
 face, requiring the application of complex remote sensory 
 input devices and CCTS's. 
 
 3. There would be the possibility of roofing and 
 ribbing problems due to the cab position on the vehicle. 
 
 5. Cross-car, end-mounted cab: Three cab-shuttle car 
 concepts were conceived and discussed for this 
 configuration. The third concept was ultimately selected 
 as the recommended concept. All the ideas positioned 
 the cab across the end of the vehicle, with the longitudinal 
 axis of the conveyor intersecting the operator's body and 
 the operator's head positioned for adequate vision down 
 the chain conveyor trough. 
 
 A. The first concept positioned the cab at the 
 vehicle dump end, outboard of the conveyor drive 
 structure. The coal would be discharged using a side- 
 dump arrangement. 
 
 Advantages of the side discharge configuration included 
 
 1. The operator would have excellent, direct 
 vision when traveling to the dump point. Because no coal 
 would be on board, direct vision should be adequate when 
 traveling to the face. 
 
 2. The addition of electronic subsystems, 
 including CCTS's, could prove desirable, but would not be 
 an absolute necessity. 
 
 3. Because of the cab location, vehicles with 
 cabs wider than what would normally fit within the entry 
 dimensions could be accommodated. Thus, the loss of 
 coal-carrying capacity resulting from the installation of the 
 side-dump mechanism could be minimized or eliminated. 
 

 « 307 
 
 »■ 
 
 
 
 
 
 
 
 
 
 II 
 
 10" 
 
 II 
 
 / Cable reel 
 
 
 
 
 
 
 
 
 
 1 
 
 
 / 
 
 
 \ 
 
 
 
 1 
 
 
 
 Control case 
 
 
 Tram motor 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 43" 9 
 
 V 
 
 2 
 
 .... 
 
 I 
 
 
 ] 
 
 
 Conveyor motor/ 
 
 
 1 
 
 i 
 
 
 Pump motor 
 
 
 Tram motor 
 
 \ 
 
 
 
 
 49" 
 
 
 
 
 / , 
 
 
 
 »> 
 
 1 
 
 3 
 
 6 
 
 1 
 
 
 
 
 r 
 
 
 
 i„ 
 12" 
 
 
 
 
 
 
 <m 
 
 - 46" - 
 
 « 43" »■ 
 
 
 
 
 .* X * >kK>ZKK>*X-* * * * X <k t, X X x X tf 
 
 FIGURE 3 -Transverse end-driven shuttle car. 
 
 4. Completely new vehicles probably would not 
 be required to accommodate the cabs; modification to 
 existing vehicles might suffice. 
 
 Disadvantages identified specific to the side-discharge 
 configuration included 
 
 1. The cab would have to be attached to the 
 vehicle main frame by a cantilevered I-beam approximately 
 11 ft long and 10 in deep. 
 
 2. Because the cab would be attached to the 
 vehicle, the ability of the cab to tolerate side loadings 
 would be decreased. 
 
 3. A floating cab could not be utilized, resulting 
 in a small interior space (fitting a 95th percentile male 
 would be very difficult). 
 
 4. The side discharge would require a complex 
 boom mechanism involving moving slides and other 
 apparatus. 
 
 5. The overall vehicle length would increase 
 approximately 40 in and the concept could be used only on 
 vehicles having chain conveyors at least 56 in wide. 
 
 6. The operator could be exposed to significant 
 amounts of dust and noise during the coal discharge 
 process. 
 
 The disadvantages were of such magnitude that this 
 concept was eliminated from further consideration. 
 
 B. The second concept would also position the cab 
 across the normal boom end of the machine, but would 
 eliminate the boom and shorten the conveyor to permit a 
 bottom-dump arrangement. This would greatly simplify 
 the cab mounting (fig. 4). 
 
 Specific advantages defined for the bottom discharge 
 configuration were that 
 
 1. A semifloating cab attachment design could 
 be employed which would provide ample interior space for 
 a wide range of operator sizes. 
 
 2. A coal discharge boom would not be 
 necessary, which would decrease design complexity and 
 minimize decreased coal-carrying capacity. 
 
 3. The operator would have excellent direct 
 vision when traveling to the dump point. Because no coal 
 would be on board, direct vision should be adequate when 
 traveling to the face. 
 
 4. The addition of electronic subsystems, 
 including CCTS's, could prove desirable, but would not be 
 an absolute necessity. 
 
 5. Because of the cab location, vehicles with 
 cabs wider than what would normally fit within the entry 
 dimensions could be accommodate. Thus, the loss of coal- 
 carrying capacity, created by shortening the conveyor to 
 accommodate the bottom discharge, could be minimized 
 or eliminated. 
 
Shuttle car 
 
 4 
 
 36" 
 
 Cab 
 
 28" 
 
 Motor 
 
 Feeder -breaker 
 
 FIGURE 4.-Bottom dump shuttle car. 
 
 6. Completely new vehicles probably would not 
 be required to accommodate the cabs; modification to 
 existing vehicles might suffice. 
 
 Disadvantages identified specific to the bottom 
 discharge configuration included 
 
 1. The section dump point would have to be 
 significantly modified, either by placing the belt or feeder- 
 breaker below ground level or requiring the vehicle to go 
 up a ramp (taking an additional 12 in of top would be 
 necessary). 
 
 2. The chain conveyor drive motor would have 
 to be relocated. 
 
 3. If a ramp was not used, an additional, 
 specialized loading machine could be required. 
 
 Disadvantages common to both the side- and bottom- 
 discharge configurations, 5A and 5B, included 
 
 1. The overall vehicle length would increase 
 approximately 40 in. 
 
 2. Operators could be vulnerable to injury from 
 obstacle collisions because of the end-mounted cabs. 
 However, the excellent direct vision provided should 
 enable operators to avoid obstacles. 
 
 3. The concepts would be limited for use on 
 vehicles having chain conveyors at least 56 in wide. 
 
 4. The operator could be exposed to significant 
 amounts of dust and noise during the coal discharge 
 process. 
 
 5. A potential problem existed in the operator 
 being able to see the coal discharged from the miner. 
 Assistance from the miner helper or augmented vision 
 could be required. 
 
 At this point, the bottom discharge configuration, 5B, 
 appeared the most attractive of all the concepts 
 considered. It seemed capable of meeting all of the 
 mandatory design criteria and most of the desirable 
 criteria, including that the operator not switch seat 
 positions depending on travel direction. The concept's 
 primary disadvantage was that the dump point site would 
 require extensive modifications. 
 
 As a result of a wooden mockup fabrication of the cab 
 and preparation-evaluation of scale drawings of modified 
 dump sites, a third concept based on the cross-car, end- 
 mounted configuration was developed. This concept, 5C, 
 positioned the cab across what would be the load end of 
 a conventional shuttle car, opposite the discharge boom 
 (fig. 5). As for the previous concepts, the operator's head 
 was positioned to maintain good direct vision through the 
 conveyor trough when traveling empty. The idea was to 
 employ the same vehicle end for both coal loading and 
 
Boom 
 end 
 
 — 307"- 
 
 110"- 
 
 Tram motor 
 
 Cable reel 
 
 Conveyor motor 
 
 Pump motor 
 
 Power box 
 
 Tram motor 
 
 36" 
 
 iio- 
 
 84" 
 
 — 32 — 
 -36— 
 
 FIGURE 5 -Transversely mounted end-cab. 
 
 unloading. This concept required no major modifications 
 to either the shuttle car or the dump site. 
 
 Previous Bureau programs had proved mockup 
 fabrications to be valuable tools in evaluating and refining 
 cab and canopy designs prior to full-scale fabrication. 
 Once the cross-cab, end-mounted cab concept was 
 determined to be feasible, detailed drawings were prepared 
 that allowed the construction of a wooden mockup cab 
 fabrication to be used with the bottom-discharge 
 configuration, 5B. Because an FMC model 6L shuttle car 
 was available and had a conveyor of sufficient 
 width to accommodate the cab, it was used for the 
 evaluation. 
 
 The 6L shuttle car is intended for use in working 
 heights higher than the 40-in target height set for the cab 
 development. Therefore, the mockup cab fabrication was 
 sized to fit the shuttle car. However, this did not decrease 
 the utility of the mockup in determining that the concept 
 was feasible; it showed there was ample operator space in 
 the cab and indicated that direct vision was even better 
 than had been assumed. 
 
 The concept maintained all of the advantages of its 
 predecessors and provided additional advantages. 
 
 1. A semifloating cab attachment design was 
 employed, which provided ample interior space for a wide 
 range of operator sizes. 
 
 2. The operator would have excellent direct 
 vision when traveling to the dump point. Because no coal 
 would be on board, direct vision down the empty conveyor 
 should be adequate when traveling to the face. 
 
 3. The addition of electronic subsystems, 
 including video monitors, proved desirable, but would not 
 be an absolute necessity. 
 
 4. Completely new vehicles probably would not 
 be required to accommodate the cabs; modification to 
 existing vehicles might suffice. 
 
 5. The concept could be readily adapted to 
 many existing shuttle cars with only limited modifications. 
 Examples would be the National Mine Service (EIMCO) 
 MC 28 and the FMC 5L shuttle cars. 
 
 6. Exposure to dust and noise problems during 
 coal discharge would be eliminated. 
 
 7. No modifications to the off-loading site would 
 be required. 
 
 8. The shuttle car could have increased coal- 
 carrying capacity, compared with current designs, since 
 eliminating the cab on the side of the car would permit the 
 use of wider cars in the same size entry. 
 
 Only two potential disadvantages were identified for the 
 concept 
 
 1. The operator would have limited direct vision 
 for determining the size of the coal pile as the mining 
 machine loads the car. However, tests using a mockup of 
 the cab were conducted and showed that the direct vision 
 could be easily augmented through the use of CCTS's. 
 
 2. The operator must turn the vehicle and then 
 travel to the dump site with limited direct vision. This also 
 
10 
 
 should not be a big problem, since the required travel 
 distance would be very short (e.g., 15 ft). 
 
 In order to determine if these two problems could be 
 overcome through the use of remote vision assist, a quick 
 experiment was performed to determine the suitability of 
 this technique. The wooden cab mockup was placed 
 adjacent to the FMC 6L shuttle car. A video camera 
 aimed at the front of the car was linked to a video monitor 
 
 mounted inside the cab. An operator was placed inside 
 the cab and watched the monitor as coal was loaded into 
 the shuttle car with a conveyor (fig. 6). The operator had 
 no trouble determining when the coal pile was high 
 enough to be moved. From this experiment, it was 
 determined that the concept with the auxiliary CCTS 
 would be a workable design. 
 
 DESIGN CONSIDERATIONS 
 
 During the predesign stage of the compartment- 
 machine development, the basic operational requirements 
 were defined. Tasks that the machine must be able to 
 perform were analyzed in relationship to their importance 
 in completing a duty cycle mission. The design was 
 considered to be a total systems program to be pursued 
 systematically. Components were not designed in terms of 
 their individual function but rather in terms of their impact 
 on the entire system, which include the needs of the 
 machine, the needs of the operator compartment, and the 
 needs of the operator. System requirements were defined 
 in terms of operational requirements, functions required to 
 complete each duty cycle, performance requirements for 
 each function, and the relationship between the equipment 
 and operator needs. 
 
 The design requirements were broken into separate 
 categories. The mandate of the project, to give at least 
 equal consideration to the needs of the operator and the 
 machine requirements, was maintained at all times 
 throughout the design process. 
 
 The following factors were determined important for 
 the operator to safely complete a duty cycle: 
 
 1. The primary consideration was that the operator 
 always be protected from accidents and possible injury. 
 The operator compartment canopy should be substantial 
 and located to protect the operator from falls of roof and 
 rib. Additionally, the compartment itself should be 
 designed to prevent the operator from leaning out and 
 being pinched or pinned between the machine frame and 
 the roof or rib. 
 
 2. The operator should have adequate direct vision to 
 essential elements. The major complaint about low-coal 
 canopies is the severe restrictions they impose on operator 
 field of view. Therefore, a serviceable design must insure 
 optimum field of view in an environment that inherently 
 restricts it. Operator visual requirements were broken 
 down on a task-by-task basis. For example, during 
 tramming, the operator must be able to ascertain the 
 relative position of the shuttle car in the roadway, the 
 machine velocity, and the relative location of the machine 
 in the mine. During loading, the operator must determine 
 the rate that coal flows from the tail boom of the miner, 
 the relative positions of the shuttle car and the mining 
 machine, the height of the tail boom, and the position and 
 height of the coal load on the shuttle car. During 
 dumping, the operator must determine the status of the 
 dump site, the position of the machine relative to the 
 
 dump site, the position of the coal load on the vehicle, and 
 the height of the tail boom. Finally, the operator must 
 always be able to determine the location of obstacles, 
 hazards, and other mine personnel. 
 
 3. The control design layout must be logical and meet 
 behavioral expectations of the operator. Control systems 
 that are radically different from what people are used to 
 or expect tend to induce operator error and confusion. 
 Controls should meet the requirements outlined in Society 
 of Automotive Engineers (SAE) XJ1314 "Human Factors 
 Design Guidelines For Underground Mining Equipment" 
 (table 1). These same considerations should be given to 
 auxiliary visual displays, auditory displays, and other 
 sensory input devices. 
 
 4. Operator comfort must be a primary consideration 
 in order to prevent fatigue and the resulting lack of 
 attention to the job and its inherent dangers. The 
 operator must have adequate room so as not to be 
 cramped and confined. This requires a wide enough 
 compartment so the operator does not feel restrained. 
 Additionally, as the canopy height becomes lower, the 
 compartment must become increasingly longer to 
 accommodate the operator. 
 
 5. The operator seat must provide operator 
 comfort and prevent fatigue. Most original equipment 
 manufacturer low-coal shuttle car seating is inadequate, 
 proper seating should be padded and equipped with an 
 adjustable back (with lumbar support) and an adjustable 
 head rest. Specific requirements are that 5th percentile 
 female through 95th percentile male operators see over the 
 top of the machine frame, and, the seat width be adequate 
 for the 95th percentile male (fig. 7). 
 
 6. The compartment design should not impede 
 operator ingress and egress. Openings must be free of 
 obstacles that may snag the operator's belt, cap-lamp 
 battery, and self-rescuer. Two important design features 
 can be employed to aid the operator. One is to use as 
 many handrails and handholds as are feasible to facilitate 
 quick and smooth ingress-egress. Another important 
 design consideration involves alternative exits. There are 
 situations when the operator must exit in a hurry (e.g., 
 roof falls, fire, inundation, etc.). If the main egress route 
 from the machine is blocked, there should be an 
 alternative way out. This alternative escape opening 
 should measure, at a minimum, 18 by 30 in. 
 
11 
 
 FIGURE 6 -Vision-assist test. 
 
12 
 
 TABLE 1. 
 
 - Recommended control motk 
 
 Control device 
 
 Motion and response 
 
 Foot pedals 
 
 Push to - 
 
 
 Activate. 
 
 
 Accelerate (forward). 
 
 
 Apply brakes. 
 
 
 Turn on or off. 
 
 
 Engage a function. 
 
 
 Release to - 
 
 
 Deactivate. 
 
 
 Decelerate. 
 
 
 Release. 
 
 
 Disengage. 
 
 
 Push to- 
 
 
 Move forward. 
 
 
 Increase. 
 
 
 Lower. 
 
 
 Activate. 
 
 
 Pull to- 
 
 
 Stop. 
 
 
 Move backwards. 
 
 
 Brake. 
 
 
 Raise. 
 
 
 Push to engage-disengage. 
 
 Rotary switches . . . 
 
 Turn clockwise to increase. 
 
 Toggle switches . . . 
 
 Push up to - 
 
 
 Select a function. 
 
 
 Activate. 
 
 
 Push down to deactivate. 
 
 Emergency cutoff . . 
 
 Push to deactivate. 
 
 Cranks or wheels . . 
 
 Turn (clockwise) to - 
 
 
 Start. 
 
 
 Increase speed. 
 
 
 Turn right. 
 
 7. Where necessary, auxiliary sensory inputs to the 
 operator should be provided. Because of the extremely 
 confined space in a low-coal operator compartment, it is 
 highly unlikely that an operator can directly perceive all of 
 the information desired to safely control the vehicle 
 operation. For maximum efficiency, the operator should 
 have direct vision to as many important visual attention 
 locations as possible. Auxiliary sensory inputs should 
 provide the operator information on blind spots that 
 cannot be directly viewed or otherwise perceived. 
 
 8. The operator compartment-shuttle car must be 
 designed for the extremes rather than the average 
 operator. Efficient operation requires that each operator 
 be perfectly positioned, allowing performance of the 
 required tasks with a minimum of stress. To 
 accommodate the majority of users, a good design provides 
 adequate space for a comfortable operating position and 
 places controls within easy reach for a 6-ft 3-in male 
 dressed in mining clothes with hardhat, cap lamp, and self- 
 rescuer. 
 
 The requirements for the machine to successfully 
 complete its mission duty cycle require equal 
 consideration. Any design would be useless if the primary 
 
 
 
 Dimensions, In 
 
 5fh-percentile 
 
 95th-percentile 
 
 
 
 female 
 
 male 
 
 / 
 
 Shoulder height 
 
 19.7 
 
 25.7 
 
 2 
 
 Eye-to- helmet top 
 
 6.0 
 
 6.5 
 
 3 
 
 Forearm -hand length 
 
 15.3 
 
 20.2 
 
 4 
 
 Buttock -knee length 
 
 20.5 
 
 259 
 
 5 
 
 Buttock- leg length 
 
 38.0 
 
 46.1 
 
 6 
 
 Back-of-knee height 
 
 14.8 
 
 18.2 
 
 7 
 
 Shoulder breadth 
 
 14.1 
 
 20.1 
 
 8 
 
 Hip breadth 
 
 12.9 
 
 15.4 
 
 9 
 
 Eye height 
 
 26.9 
 
 33.9 
 
 10 
 
 Sitting height 
 
 30.9 
 
 38.4 
 
 II 
 
 Sitting height 
 with helmet 
 
 32.9 
 
 40.4 
 
 FIGURE 7.-Coal miner anthropometrics. 
 
 function of the machine could not be efficiently 
 accomplished. 
 
 1. The first limitation is the design criteria that the 
 cab-machine operate in a 40-in working height coal seam. 
 Although previous studies showed that a significant 
 number of shuttle cars operate in coal seams between 42 
 and 48 in without canopies, due to court-obtained 
 variances, the advisory committee decided the project goal 
 should be set below the cutoff point of 42 in set forth in 30 
 CFR 75.1710. Based on this, a target goal of 40 in was set. 
 It was felt that a successful compartment-shuttle car design 
 for this seam height would be a significant accomplishment 
 and could be approached with a reasonable degree of 
 confidence. 
 
 2. The concept should be adaptable, with minimal 
 modifications, to as many existing shuttle cars as possible. 
 It is realized that to achieve the project goals the final 
 design will have to depart from traditional design concepts 
 and practices; historically, no one has been able to resolve 
 this issue since shuttle cars were introduced into the 
 mining industry in the 1930's. However, use of as much of 
 the currently available base vehicles as possible will reduce 
 costs and increase acceptance in the mining community. 
 
 3. No mining system equipment modifications should 
 be required to accommodate the new equipment. Several 
 designs were considered that would have necessitated 
 
extensive modifications to the dump sites and tail boom of 
 the miner. However, these would have significantly 
 increased the cost of the system and hindered acceptance. 
 
 4. The addition of the cab should cause no decrease in 
 coal-carrying capacity. The primary mission of a shuttle 
 car is to rapidly carry as much coal as possible from the 
 m inin g machine to the dump site. Time studies have 
 shown that haulage is the biggest bottleneck in the 
 
 13 
 
 production cycle; a bigger bottleneck would not help a new 
 system gain acceptance. 
 
 5. Adequate tram clearance must be provided for the 
 shuttle car to efficiently complete its mission. Vehicles 
 must be able to achieve maximum operating velocities 
 without "ribbing" or "roofing" (striking the ribs or roof) to 
 maximize production, maintain a stable workflow, and 
 permit safe and efficient operation. 
 
 DESIGN PROCEDURE 
 
 The design concept chosen was a cross-car, end- 
 mounted configuration that positioned the cab across what 
 would be the load end of a conventional shuttle car, 
 opposite the discharge boom. The operator is positioned 
 across the end of the vehicle, perpendicular to the 
 longitudinal axis of the chain conveyor. This arrangement 
 would give the operator unobstructed vision when 
 tramming to the dump site and very good direct vision 
 down the empty conveyor when tramming to the face. The 
 main disadvantage appeared to be increased complexity of 
 procedures when unloading coal. The idea was to employ 
 the boom end of the vehicle for both coal loading and 
 unloading. This would require the operator to back up a 
 short distance to the dump site with his or her direct 
 vision obstructed by the coal pile. 
 
 The specific design procedures were followed in 
 accordance with the experience the Bureau has developed 
 in cab design in over a decade of work in this area. The 
 transversely mounted, end-cab (TMEC) concept selected 
 for further development was analyzed to insure that it 
 would meet the previously established performance 
 criteria. A technical description of the proposed shuttle 
 car cab concept was sent to major U.S. shuttle car 
 manufacturers to solicit their comments. The responses 
 received were very favorable and encouraging. 
 
 The TMEC concept needed to be refined and finalized 
 to better adapt it to existing low-coal shuttle cars. The 
 first task was to finalize the design of the basic 
 compartment structure (fig. 8). The optimal compartment 
 
 ■72' 
 
 -I8"-»| 
 
 i 
 
 2 Typical 
 
 1 
 
 1 — V 
 
 24" 
 
 40" 
 
 A 
 
 A 36" +. 
 
 6" 
 
 3^ Typical 
 36"- 
 
 -4 
 
 L 6" 
 FIGURE 8-Compartment design. 
 
 28"- 
 
14 
 
 dimensions were determined to be 36 in wide by 72 in long 
 by 36 in high. 
 
 The 36-in width provides an operator with sufficient hip 
 room and freedom of movement. This width should not 
 interfere with the capability of the shuttle car to tram 
 around corners; it is the approximate dimension the 
 unused load end of the vehicle can be shortened without 
 altering the stock chain conveyor or decreasing haulage 
 capacity. The 72-in compartment length provides the 
 operator with extra leg room for comfort in a reclined 
 seating position. The 36-in canopy height should provide 
 ample clearance to prevent roofing in a 40-in coal seam, 
 since the operator compartment is designed to be a 
 full-floating cab. Canopy support posts were placed as far 
 outboard on the operator compartment as possible, so as 
 not to interfere with operator field of vision. Finally, all 
 corners and edges of the operator compartment and 
 canopy were beveled or sloped so the compartment could 
 float over or deflect, rather than jam on any roadway 
 obstacles. 
 
 Several additional modifications necessary to adapt the 
 concept to existing shuttle cars were identified. First, the 
 cable reel will have to be moved from the boom end to the 
 cab end of the vehicle to prevent running over the trailing 
 cable. The boom end of the vehicle will need additional 
 reinforcement, since it is now used for both loading and 
 dumping. Finally, the cab end of the shuttle car will need 
 to be shortened 36 in to facilitate tramming around 
 corners. None of these modifications should affect 
 operation or decrease coal-carrying capacity, since wider 
 shuttle cars can be used in the same width entries with the 
 operator cab relocated from the side of the car. 
 
 Design details of the compartment and related 
 components (seating and controls) were evaluated using 
 several of the Bureau's computer modeling programs. 
 
 The first program used was the crew-station assessment 
 of reach (CAR) program; it insured that all the shuttle car 
 controls are at optimum reach locations. Numerous 
 control layouts (fig. 9) were designed and analyzed. These 
 layouts placed the controls within easy reach of all 5th to 
 95th percentile operators without interfering with required 
 vision. All of the selected controls are small electrical 
 units that activate relay-controlled solenoids. This use 
 results in considerable space savings within the cab as 
 compared with employing conventional, bulky, hydraulic 
 valves and associated hoses. The control layout selected, 
 after the computer analysis, is shown in figure 10. This 
 design provides a control panel that is positioned in front 
 of and within easy reach of the operator. It swings out of 
 the way to provide easy ingress and egress. 
 
 The second program was the "CAP" crew-station 
 analysis program (CAP), which analyzed the 
 anthropometric parameters of the cab and checked 
 operator vision at predetermined-required visual attention 
 locations. This program generates a simulation of the 
 operator field of vision from within the shuttle car to 
 predetermined vision points (fig. 11). These points are 
 then weighted and compared to a list of required visual 
 attention locations established from previous Bureau 
 
 Swing away 
 control box bracket 
 
 Monitor 
 
 /-Multifunction 
 joystick 
 
 Control box 
 
 Power - 
 
 Swing away 
 control box bracket 
 
 Control box 
 
 Multifunction 
 
 joy stick - 
 
 Modular 
 control box 
 
 Monitor 
 
 FIGURE 9.-Control layouts. 
 
15 
 
 programs. The TMEC provided field of vision superior to 
 even the operator compartments without canopies now in 
 use in low-coal seams. 
 
 The next component to be designed was the seat for the 
 shuttle car operator. Because of the limited confines of 
 low coal, the operator must be as comfortable as possible 
 in order to effectively perform for an 8-h or longer shift. 
 After careful consideration, a seat designed under a 
 previous Bureau project was selected. This seat (fig. 12) 
 permits the operator to sit in the required reclined 
 position. Important features include lumbar support and 
 an adjustable back to permit smaller operators to sit in a 
 more upright position. The seat pad is 15 in long, 22 in 
 wide and has an adjustable tilt. It is short enough to 
 
 Swing away 
 control box bracket 
 
 Monitor 
 
 Orbital 
 steering 
 
 Control box 
 
 FIGURE lO.-Selected control layout 
 
 prevent cutting off circulation in the legs and wide enough 
 to provide adequate hip room. Another important feature 
 is an adjustable, preshaped support; it holds the head and 
 neck in a comfortable, upright position, allowing protracted 
 periods of operation. The entire seat is contoured to hold 
 the operator securely, formed of foam padding covered 
 with vinyl fabric. An option under consideration is a seat 
 belt with a Velcro hook-and-loop fastener, a rigid locking 
 belt is not needed but a lightweight, easily fastened belt 
 using a Velcro hook-and-loop fastener would help secure 
 the operator in the seat when tramming over rough 
 bottom. 
 
 Previous testing had determined that auxiliary vision 
 assist would be necessary. The final design employs the 
 most favorable and cost-effective solution -it allows the 
 operator direct vision to as many of the required visual 
 attention locations as possible. Direct vision is 
 supplemented by providing visual input at the blind spots 
 through the use of a simple CCTS. The CCTS provides 
 visual assistance for those reference points where the 
 operator requires additional information. The system 
 provides an overlap of direct and transmitted vision so that 
 (1) the operator is given a point of reference between 
 direct view of an object and the view of the same object on 
 the monitor, and (2) the operator is given a choice, where 
 possible, between the direct and transmitted view of 
 objects. 
 
 The final system consisted of one closed-circuit camera 
 enclosed in a protective, explosion-proof housing mounted 
 on the boom end of the shuttle car, and, one black-and- 
 white monitor located inside the operator compartment. 
 It was determined that only two areas required vision 
 assistance: a view of the coal flowing from the boom of the 
 continuous miner and a view of the dump site when 
 backing to it. Therefore, a two-position rotary actuator 
 was selected to pan the camera 90°; no camera tilt was 
 deemed necessary. 
 
 FIGURE 11. -Computer-generated field of vision. 
 
16 
 
 FIGURE 12.-Shuttle car operator seat. 
 
 MOCKUP AND EVALUATION 
 
 The mockup and evaluation of a proposed operator 
 compartment, prior to the construction of a full-scale 
 prototype, has proven to be a useful tool in refining design 
 deficiencies and allowing improvements at an early stage 
 of the project development. It was decided that, to 
 accurately evaluate the proposed operator compartment- 
 shuttle car concept, a semifunctional mockup needed to be 
 constructed. The completely unique position of the 
 operator compartment, with respect to the shuttle car, 
 posed a question as to whether or not an operator could 
 effectively control the machine from the cross-car position. 
 
 To construct the working mockup, a steel platform was 
 welded to the end of a functioning MC36 shuttle car. This 
 served as a base on which to construct the compartment 
 mockup. The available shuttle car was not a low-coal 
 shuttle car, having a 36-in frame height. Therefore, the 
 base plate was positioned 16 in above the ground to 
 simulate the spatial and visual conditions the operator 
 would perceive when the compartment was installed on a 
 shuttle car with a 28-in frame height. The previously 
 selected control system layout was installed along with the 
 selected operator seat and the CCTS. Fully functional 
 steering, brake, and tram controls were employed so that 
 
 the actual feel of driving the shuttle car could be 
 evaluated. 
 
 Once the mockup was completed and all systems were 
 functioning, a surface evaluation of the system was 
 conducted. Several experienced operators trammed the 
 shuttle car through a predetermined course; equipment 
 performance and operator comments were noted. The 
 operator compartment was then evaluated based on the 
 previously established project criteria. 
 
 The overall results of the evaluation were encouraging. 
 After a brief practice period to orient themselves to the 
 new system, the operators were able to maneuver the 
 shuttle car through the course with comparative ease. 
 Operator comments primarily centered on a dramatic 
 increase in field of vision and space when comparing the 
 new design to traditional shuttle car operator 
 compartments. Operator ingress-egress was accomplished 
 with relative ease, and the seating was easily adjusted to 
 accommodate all operators. In general, the proposed 
 operator compartment-shuttle car concept appeared to be 
 a feasible and efficient solution to the difficult problem of 
 providing protection for thin-seam shuttle car operators. 
 
17 
 
 CHANGES RESULTING FROM MOCKUP 
 
 Although primarily successful, the evaluation identified 
 several improvements that should be incorporated in the 
 control layout. These improvements were to better 
 accommodate a 95th percentile male operator. The swing- 
 away control panel located in front of the operator 
 enhanced ingress-egress for most operators, but tended to 
 hit the legs of very large operators. Therefore, the 
 decision was made to place the operator controls in a 
 more traditional location on the side of the operator 
 compartment. This arrangement does not provide the 
 same ease of reach to the controls, but is satisfactory and 
 does permit the accommodation of a greater segment of 
 the operator population. 
 
 The second improvement was to modify the standard, 
 orbital steering unit used to maneuver the shuttle car. 
 Previous experience with the anthropometric design of 
 steering units had shown that positive directional steering 
 (where the shuttle car turns right when the wheel is turned 
 clockwise and left when the wheel is turned 
 counterclockwise) is the most desirable design philosophy. 
 However, for some operators, it did not always function as 
 expected for this unique situation. The design does not 
 require the operator to change seating positions according 
 
 to the direction of travel. Based on learned behavior from 
 driving an automobile, an operator's performance 
 expectation could be that the steering direction would be 
 opposite when traveling in the opposing directions. Since 
 this was a problem for some operators, it was assumed 
 that changing the steering to a nonpositive pattern could 
 cause problems for the operators that had adjusted to the 
 original system. The solution was to convert the standard 
 orbital steering, through the use of a gearing mechanism, 
 into a joystick-type steering (fig. 13). This new system 
 steers the car to the right whenever the joystick is pushed 
 to the right and vice versa regardless of tram direction. 
 
 Once these modifications were incorporated into the 
 compartment mockup (fig. 14), the evaluation trials were 
 repeated. Since the new steering system had no 
 conceptional relationship with an automobile, all operators 
 readily adapted to the redesigned steering and were easily 
 able to maneuver the shuttle car in either tram direction. 
 The second set of trials went smoothly with no perceivable 
 major problems remaining. The compartment design now 
 appears ready for full-scale fabrication and test of proof- 
 of-concept. 
 
 FIGURE 13.-Joystick steering. 
 
18 
 
 FIGURE 14.-Final mockup. 
 
 CONCLUSIONS 
 
 From the work completed, it appears that the Bureau 
 of Mines TMEC concept for a operator compartment- 
 shuttle car is a feasible and safer solution to the problem 
 of implementing protective operator structures on low-coal 
 shuttle cars used in 40-in working heights. The developed 
 concept provides good operator protection from the 
 hazards of roof falls and eliminates the possibility of 
 pinching-squeezing accidents (responsible for 90 pet of all 
 shuttle car accidents). The concept overcomes the primary 
 objection to canopies -the lack of direct vision. Its unique 
 location on the shuttle car takes advantage of the empty 
 conveyor to provide the operator with a direct line of sight 
 to the vast majority of required visual attention locations. 
 The design also provides the operator with ample space 
 for comfort. Additionally, this concept meets all of the 
 
 design criteria established by the project advisory 
 committee. 
 
 It is anticipated that the project will continue through 
 the fabrication of a full-scale prototype for proof-of- 
 concept underground evaluation. Future work will include 
 the fabrication of a generic compartment that can be 
 adapted to an existing shuttle car and the detailed 
 specifications for a shuttle car incorporating the concept. 
 
 Specific tasks should include fabrication of a generic 
 compartment and all related hardware. A compartment 
 should be constructed that can be adapted to a modified 
 low-coal shuttle car when one becomes available. All of 
 the control systems and hydraulic modifications should be 
 constructed and tested on a currently available high-coal 
 shuttle car to verify correct function and suitability. 
 
 REFERENCES 
 
 1. Bartels, J. R, A. J. Kwitowski, W. D. Mayercheck. Protective 
 Structures for Low-Coal Shuttle Car Operator. BuMines RI 9143, 1987, 
 22 pp. 
 
 2. Kramer, J. M. (Mine Safety and Health Administration, 
 Pittsburgh, PA). Personal Communication, Aug. 1986; available upon 
 request from A. J. Kwitowski, BuMines, Pittsburgh, PA. 
 
 3. Lindahl, P. D., and K L. Whitehead. Cost Benefit Analysis of 
 Low-Coal Cabs and Canopies, (contract J0199005, Bituminous Coal 
 Res.). BuMines June 1982. OFR 124-85, Nov. 1983, 144 pp.; NTIS PB 
 86-138930. 
 
 4. Kwitowski, A. J., and R J. Gunderman. Development of a 
 Protective Operator Compartment for a Thin-Seam Mobile Bridge 
 Carrier. BuMines IC 9093, 1986, 27 pp. 
 
 5. Mantel, J. Development and Assessment of New and Existing 
 Canopy Technology to Lower Coal Seams, (contract H0387026, ESD 
 Corp.). BuMines OFR 7-86, June 1985, 101 pp. 
 
 6. Troyer, M. Test Program for Automatic Steering Shuttle Car. 
 Final Report (contract J0155048, Bendix Corp.). BuMines OFR 51(1)- 
 77, 1976, 73 pp.; NTIS PB 265 178. 
 
 INT.-BU.OF MINES.PGH..PA 28772 
 
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