■ ^1 ' I I ■ ■ ■ VVafj ■ I ■ H I ■ ■ H l I itp. WwkMr h : h Hi A>*t, v*cr O. - «, « o - « , *s *o . » * a. .* +jt« civ *>% °„ .*«* W 'Zffr\& %> **- * * A A* * ** ^ • c&zffi J- \;-?^' % o'* \*^^\y %/^Sv* \^ffij?': fe\ '°tfi&> /^&\ **$&>> yV^ak-X <°^>" ^ «*°* *oV* %/ *°A ^ v o^ %**^??*v* V^^* \/??ffid? V* ; /^ \/^^v* J^\ Library of Congress Cataloging in Publication Data: Evans, Robert J. Coal extraction, transport, and logistics technology for underground mining. (Information cirular ; 9181) Bibliography: p. 79-81. Supt. of Docs. no.: I 28.27:9181. 1. Coal mines and mining. I. Mayercheck, William D. II. Title. III. Series: Information circular (United States. Bureau < 3f Mines ) 9181. TN295.U4 [TN802] 622\334 87-600440 CONTENTS Page Abstract 1 Introduction 2 Acknowledgments 3 Coal extraction technology 3 Automated extraction system II 4 Umbrella miner 9 Remote operating system 14 Variable wall miner system 19 Bidirectional auger 22 Coal transport technology 27 Hopper-feeder-bolter 28 Monorail bridge conveyor 34 Multiple-unit continuous haulage system 40 Automated bridge conveyor train 46 Flywheel-powered shuttle car 49 Flip-top canopy 52 Commercially available Bureau-sponsored transport projects 58 Maximum-capacity shuttle car 58 Diesel-powered face haulage vehicle 58 Mobile bridge conveyor operator compartment 58 Flexible conveyor train 60 Coal mine logistics technology 61 Conveyor belt service machine 61 Materials handling devices 64 Scoop-mounted boom hoist 65 Lift-transport mechanism 65 Machine-mounted swivel crane 67 Container-workstation transporter 67 Timber car 67 Diesel-powered f orklif t 70 Track maintenance vehicle 70 Returning coal waste underground 72 Surface-testing prototype mine equipment 73 Future Bureau research efforts 78 Summary 79 References 79 ILLUSTRATIONS 1. U.S. underground coal production by mining method 4 2. Automated extraction system II 5 3. Automated extraction system machine components 8 4. Typical mine plan and cut sequence for break-to-break mining with automated extraction system 9 5. Automated extraction system at Bureau's surface test facilities 10 6. Umbrella miner with augers in tramming mode 10 7. Umbrella miner straight-ahead mining 10 8. Umbrella miner turning a crosscut 11 9. Major components of umbrella miner 11 10. Umbrella miner chain conveyor system 14 11. Umbrella miner in surface test facility 15 11 ILLUSTRATIONS— Continued Page 12. Continuous miner designed for remote operation 17 13. Artist's illustration of remote operator compartment 17 14. Prototype remote operator compartment 18 15. Using remote operation for mining a thin seam in a surface mining highwall 19 16. End and plan views of variable wall miner system 20 17. Surface-testing of variable wall miner system 20 18. End view of variable wall miner auger string 21 19. Variable wall miner face assembly 22 20. Closeup view of variable wall miner auger 24 21. View of partial auger string and connecting shafting 25 22. Bidirectional auger prior to in-mine trials 25 23. Conceptual plan for partial pillar extraction with bidirectional auger.... 27 24. Typical ventilation plan for pillar extraction with bidirectional auger... 28 25. Bidirectional auger underground in an Illinois coal mine 29 26. Hopper-feeder-bolter in surface test facility 30 27. Bolter module of hopper-feeder-bolter 30 28. Major components of hopper-feeder-bolter 31 29. Hopper-feeder-bolter handheld remote control unit 33 30. Operating sequence of hopper-feeder-bolter beside a two-pass continuous miner 33 31. Three types of monorail bridge conveyor units 34 32. Plan view of monorail bridge conveyor unit 35 33. Inby unit of monorail bridge conveyor 35 34. Pendant control for monorail bridge conveyor 37 35. Monorail hardware 37 36. Monorail track 38 37. Monorail bridge conveyor used with hopper-feeder 38 38. Monorail bridge conveyor interface with hopper-feeder 39 39. Monorail bridge conveyor mine plan for room-and-pillar mining 39 40. Monorail bridge conveyor mine plan for longwall panel entry development... 40 41. Monorail bridge conveyor used with shortwall mining system 40 42. Monorail bridge conveyor underground installed over a section belt 41 43. Multiple-unit continuous haulage system 42 44. Vehicle-to-vehicle mechanical linkage steering subsystem for multiple-unit continuous haulage 42 45. Multiple-unit continuous haulage undercarriage showing installation of mechanical linkage steering subsystem 43 46. Lead vehicle of multiple-unit continuous haulage system 43 47. Intermediate vehicles of multiple-unit continuous haulage system 45 48. Protective enclosure for multiple-unit continuous haulage lead vehicle.... 45 49. Automated bridge conveyor train 47 50. Automated bridge conveyor train centering itself about guidance cable 47 51. Typical room-and-pillar mine plan for automated bridge conveyor train 48 52. Inby unit of automated bridge conveyor train undergoing surface tests 49 53. Flywheel-powered coal mine shuttle car 50 54. Seven-rotor flywheel for flywheel-powered coal mine shuttle car 50 55. Mission duty cycle of flywheel-powered coal mine shuttle car 50 56. Energy storage system for seven-rotor flywheel of flywheel-powered coal mine shuttle car 51 57. Energy used in duty cycle of flywheel-powered coal mine shuttle car 53 58. Power system of flywheel-powered coal mine shuttle car 53 ILLUSTRATIONS— -Cont inued iii Page 59. Flip-top canopy, side view 54 60. Flip-top canopy, rear view 55 61. Flip-top canopy, front view 55 62. Flip-top canopy showing head and leg room 57 63. Flip— top canopy actuator control 57 64. Flip-top canopy sling-type seat 58 65. Maximum-capacity shuttle car 59 66. Diesel-powered face haulage vehicle 59 67. Mobile bridge conveyor operator compartment 60 68. Flexible conveyor train 60 69. Conveyor belt service machine 62 70. Conveyor belt service machine with operator in tramming mode 62 71. Conveyor belt service machine with hitch mechanism attached to belt tailpiece 64 72. Scoop-mounted boom hoist 66 7 3. Lift-transport mechanism 66 74. Machine-mounted swivel crane 67 75. Container-workstation transporter 68 76. Timber car 69 77. Diesel-powered f orklif t 70 78. Track maintenance vehicle 71 79. Track maintenance vehicle brush assembly 72 80. Track maintenance vehicle material removal system 72 81. Typical filter barricade for returning coal waste underground 74 82. Returning coal waste underground, backfilling sequence — phase 1 75 83. Returning coal waste underground, backfilling sequence — phase 2 75 84. Returning coal waste underground, backfilling sequence — phase 3 76 85. Flow of refuse material in returning coal waste underground 76 86. Main components of Bureau's mining surface test facility 77 87. View inside surface test facility staging area 77 88. View inside surface test facility maneuverability trial area 78 TABLES 1. U.S. underground coal production for mines producing over 100,000 st 3 2. Automated extraction system II specifications 6 3. Umbrella miner specifications 12 4. Specifications for remote operation of thin-seam continuous miner 16 5. Variable wall miner system specifications 23 6. Bidirectional auger specifications 26 7. Hopper-feeder-bolter specifications 32 8. Monorail bridge conveyor system specifications 36 9. Multiple-unit continuous haulage system specifications 44 10. Automated bridge conveyor train system specifications 48 11. Flywheel-powered shuttle car specifications 52 12. Comparison of various face haulage vehicles 54 13. Specifications for shuttle car and flip-top canopy operator compartment... 56 14. Conveyor belt service machine specifications 63 15. Analysis of in-mine materials handling accidents 65 16. Summary of major health and safety analysis findings 65 UNIT OF MEASURE ABBREVIATIONS USED IN THIS REPORT A ampere kip/in 2 kip per square inch A«h ampere hour kV«A kilovolt ampere deg degree kW kilowatt ft foot kW«h kilowatt hour ft 3 cubic foot lb pound ft- lb foot pound lb/ft pound per foot f t/min foot per minute lbf/ft 2 pound (force) per square foot ft 3 /min cubic foot per minute lbf/in 2 pound (force) per gal gallon square inch gal/min gallon per minute mi/h mile per hour h hour min minute hp horsepower Vim micrometer Hz hertz pet percent in inch r/min revolution per minute in 2 square inch s second in Hg inch of mercury st short ton in H 2 inch of water st/h short ton per hour in*lb inch pound st/min short ton per minute in/rain inch per minute st/yr short ton per year in/r inch per revolution V ac volt, alternating current in/s inch per second V dc volt, direct current kA kiloampere W-h watt hour kHz kilohertz yr year COAL EXTRACTION, TRANSPORT, AND LOGISTICS TECHNOLOGY FOR UNDERGROUND MINING By Robert J. Evans 1 and William D. Mayercheck 2 ABSTRACT The Bureau of Mines is sponsoring a variety of long-term, high-risk research to advance state-of-the-art technology in U.S. underground coal mining. This report reviews the status of many Bureau projects that support fundamental underground coal mining operations; the project areas include cutting coal from the solid (extraction), hauling coal from the face (transport), and activities that sustain daily operations (logistics). Innovative equipment and technology have been developed, with these major objectives: to significantly improve coal mine produc- tivity, to further advance coal recovery and personal safety within the mining industry, and to reduce the time needed to develop longwall pan- els. The majority of the prototype equipment covered in this report either has undergone or will undergo comprehensive evaluation at Bureau surface test facilities so that performance and reliability can be im- proved before the equipment is tested and evaluated in a working section underground. _Civil engineer. Supervisory phy; Pittsburgh Research Center, Bureau of Mines, Pittsburgh, PA. ^Supervisory physical scientist. INTRODUCTION The prime reason for past growth in the coal industry has been the ability to provide a low-cost fuel to consumers. Future growth will also depend upon main- taining and improving the ability to remain competitive with other energy resources. To remain cost competitive, the coal industry requires innovative and efficient equipment that will provide more flexibility in the ever-changing underground conditions caused by the nec- essity of mining coal seams from deeper, thinner, dirtier, and gassier coalbeds. The U.S. mining industry is also en- countering increasingly stiffer competi- tion from foreign coal sources. While the United States is one of the world's largest producers and exporters of coal, this country could import as much as 10 million st annually in the next decade, compared with 1.2 million st in 1984, according to both government and private analysts CO. Foreign coal competition, especially along the southeastern coastal States, is forcing U.S. coal to be more cost competitive with the international market. Foreign supplies of oil and natural gas during a time of national emergency could prove to be costly, insufficient, and unreliable. The dependence of the United States on foreign oil sources resulted in energy problems during the 1970's, as did the uncertainty of the domestic supply of natural gas. U.S. dependence on these uncertain sources of energy continues, even though 85 pet of the fossil fuel reserves of the United States are in the form of coal. The relative popularity of natural gas and oil over coal is largely due to the disadvantages of coal. Historically, coal has been a solid fuel that is diffi- cult to burn without adverse effects to the environment, which translate into relatively high capital costs for _ -'Underlined numbers in parentheses re- fer to items in the list of references at the end of this report. coal-fired powerplant construction and operation. However, new technologies, such as f luidized-bed combustion, that utilize coal without adverse effects to the environment may improve coal's mar- ketability (2). The Bureau of Mines embarked on a long- term, high-risk research and development program in the mid-1970's to introduce new technology into the mining industry to improve productivity and reduce the cost of coal. Innovation in underground coal mining equipment and techniques does not come about swiftly or easily, because of the capital-intensive and high-risk nature of the mining industry. Decades of research are usually required to de- velop mature products for use by the American mining industry. Abstracts of this long-term program have been included in a Bureau publication (3_) that covers the majority of the Bureau's work in es- tablishing new production technology in underground coal mine room-and-pillar and longwall entry development operations. The research results described in this report include only the portion of the Bureau's overall effort that relates to innovative mining equipment to improve mining efficiency through improved ex- traction, haulage, and logistical sys- tems. Improved resource recovery will also be achieved through the production of more efficient retreat mining equip- ment. This technology also addresses im- proved health and safety for the mining population by mechanizing or combining unit operations such as automated roof support systems, cutting extraction cy- cles, remote control, improved ventila- tion, and other advances related to un- derground mining operations. Although the various technologies described herein were designed and intended for use in U.S. deep coal mining operations, there may be other applications of these tech- nologies for noncoal deep mines, such as tunneling, and surface coal mining operations. Many coal companies, equipment manufac- turers, and other cooperators throughout the United States either have assisted or are assisting the Bureau in this program effort by testing prototype equipment in their underground coal mines. ACKNOWLEDGMENTS The authors want to extend their sin- cere appreciation to the following em- ployees of the Transport and Extraction Group of the Bureau's Pittsburgh Research Center for their technical input, which included background information, pro- totype machine specifications, and ver- sions of miscellaneous illustrations: Richard Farrar, mechanical engineer, for work on the automated extraction system, umbrella miner, variable wall miner sys- tem, and bidirectional auger; August Kwitowski, civil engineer, for work on the remote operating system, automated bridge conveyor train, and mobile bridge conveyor operator compartment; Jasinder Jaspal, raining engineer, for work on the multiple-unit continuous haulage system and conveyor belt service machine; John Bartels, civil engineer, for work on the flywheel-powered shuttle car and flip-top canopy; Richard Unger, civil engineer, for work on the materials handling de- vices and track maintenance vehicle; and Anthony Miscoe, mechanical engineer, for work on returning coal waste underground. COAL EXTRACTION TECHNOLOGY Extraction is one of the basic unit operations of the mining cycle (extrac- tion, loading, and haulage). In U.S. mines that produce more than 100,000 st/yr, approximately two-thirds of the underground coal is extracted by continu- ous miner (CM), as shown in figure 1 and table 1. The remaining third is split between longwall and conventional mining, at roughly 17 pet each i^~]_) • In spite of its name, a CM does not cut and load coal continuously over a production shift. Because the law does not permit mining personnel to produce coal under unsupported roof, intermittent work stop- pages result from place changes between the roof bolter and the CM, in addition to waiting for shuttle cars to transport extracted coal. Most mining companies estimate the CM is available for produc- tion only about 70 pet of the time, with a failure occurring on the average once every 6 h of operation (8). The CM was first introduced after World War II, and during the interim, especial- ly during the past 10 yr, it has been steadily growing in power and size. The chief motivation for this evolution has been the desire by mine operators to in- crease productivity and to improve the capability to cut rock in seam inclusions along with the roof and floor. However, as the CM horsepower increases, the size of the equipment also increases , thereby reducing its mobility and flexibility. Any further increases in extraction productivity are not expected to come about through larger and more powerful machines. As a result, the Bureau has focused its extraction research in other areas. Novel extraction techniques, such as the unique cutting drum employed on TABLE 1. - U.S. underground coal production for mines producing over 100,000 st Year Longwall Conventional Continuous Total, 10 3 st pet of total 10 3 st pet of total 10 3 st pet of total 10 3 st 1981 39,099 13 59,885 20 200,614 67 299,425 43,610 13 62,435 19 223,454 68 328,610 48,122 16 55,747 19 189,892 65 292,142 1984 54,034 16 60,789 18 222,893 66 337,717 57,816 17 57,8Q0 17 224,400 66 340,000 KEY ESS) Continuous Rn^I Conventional -EZ3 Longwall 1 400 350 300 <° o 250 O H200 a o £ 150 100 50 1981 1982 1983 1984 1985 YEAR FIGURE 1.-U.S. underground coal production by mining method. the umbrella miner has been surface tested and evaluated; and machines with combined unit operations for simultaneous coal extraction and roof support have been designed, fabricated, and surface tested. In addition, remote-control op- erating systems are being designed for mining machines that permit operation 500 ft or more from the face (9). The following are Bureau contributions to advance the state of the art of coal extraction technology, aimed at introduc- ing more efficient and safer machines to improve productivity, resource recovery, and safety. Another novel coal extraction tech- nique being developed by the Bureau, not AUTOMATED EXTRACTION SYSTEM II Objectiv e To improve productivity and safety by combining extraction, roof bolting, and face ventilation into one machine. Justificatio n The automated extraction system (AES) II was conceived and developed to combat the intermittent and inefficient nature of the continuous mining cycle, resulting from delays due to place changing of the CM and the bolter and waiting for a shut- tle car. The AES II has the potential to significantly increase productivity by combining unit operations into one machine, which reduces place changing with the roof bolter, provides greater personal safety at the face because miners are always working under a sup- ported roof, and operates at a relatively lower cost because of increased effi- ciency. In addition, this system permits use of a continuous face haulage system rather than shuttle cars. The AES II is envisioned as the first step toward an automated mining system. Des cription The AES II (fig. 2) is a second-gener- ation 15-ft drum-type CM designed and fabricated by the National Mine Service Co. (NMSC) under U.S. Department of En- ergy (DOE) and Bureau contracts (1 1-14) . It has the capacity to mine coal under manual control or with an automated cut- ting cycle via an on-board programmable controller for seam heights ranging from 6 ft 8 in to 10 ft in. In the auto- mated mode, the cutting head automatical- ly rises to the programmed height , sumps the designated distance, shears to the predetermined floor level, and cuts the cusp. It repositions itself after an covered in this report, assisted cutting (10). is water-jet- 10'max 6l"min height 30 3 extended FIGURE 2.-Automated extraction system II. advance of 4 ft and repeats the cycle. During coal extraction, an operator under temporary roof support (TRS) uses manual control to install four roof bolts span- ning 15 ft. In addition, this machine features a self-advancing system for face ventilation and dust suppression. The machine specifications are listed in ta- ble 2, and the major machine components are shown in figure 3. A typical mine plan and cut sequence for break-to-break mining is shown in figure 4. Based on surface cutting trials, it is estimated the machine has production capabilities of 8 to 10 st/min with potential to mine 2,400 st per shift. Three operators are required on the machine, one in each of the two bolter stations and the machine operator. Status Surface tests and evaluation work are under way at Bureau facilities, as shown in figure 5. A cooperator will be sought to test and evaluate the machine under- ground in a production mode after comple- tion of surface testing which is tenta- tively scheduled for early 1988. Several mechanical and electrical com- ponents developed under this program have already been incorporated into the design of commercial CM's sold by the NMSC. 5 These components include (1) a 60° swing tail universal chain, (2) a cable remote- control pendant, (3) pilot-operated sole- noid valves (first used on the AES), and (4) an anticontamination water spray sys- tem, all available on the model 2460 low coal miner, and (5) gathering head clean- up wings available on all NMSC miners, such as models 2460, 3080, 3612, and 5012. ^Reference to specific products does not imply endorsement by the Bureau of Mines. TABLE 2. - Automated extraction system (AES) II specifications MACHINE ENVELOPE DIMENSIONS Overall machine length 35 ft 11 in. Cutting head width: Extended for mining 15 ft. Retracted 13 ft 4 in. Weight 145,000 lb. Minimum tram height 5 ft 1 in. Ground clearance 6 in. Mining range (with 12-in tram top clearance) 6 ft 8 in to 10 ft. TRACTOR FRAME Ground clearance 6 in. Track type Piano hinge. Track width 21 in. Track length 9 ft 4 in. Track ground pressure: In tram mode 31 lbf/in . In mining mode 21 lbf/in . TRAM DRIVE Maximum belt pull 50,000 lb per side. Speeds 13.3 and 40 ft/min. Motors, water-cooled (2) 20 hp , 865 r/min; 50 hp, 1,715 r/min. CUTTER DRUM 1 Drum (outside diameter) 3 ft. Reach: Above grade 10 ft. Below grade 5 in. CUTTER DRUM DRIVE Motors, water-cooled (2) .- 200 hp , 1,200 r/min. Drum speed 57 r/min. Bit speed 535 ft/min. GATHERING HEAD (DISK TYPE) Width: Mining mode 15 ft. Disk size: Large 4 ft 5 in. Small 2 ft 6 in. Disk speed: Large 70 r/min. Small 177 r/min. Drive motors, water-cooled (2) 25 hp, 1,750 r/min. COAL HAULAGE CHAIN CONVEYOR Width 2 ft 6 in. Depth 5 in. Speed 350 ft/min. Loading rate at 5-in coal depth 10 st/min. Swing angle left or right of centerline 60°. Drive type Rear hydraulic. May be increased. TABLE 2. - Automated extraction system (AES) II specifications — Continued ROOF SUPPORT-OPERATOR PROTECTION SYSTEM 2 Support cylinders, 2-stage (4): Bore 7.7 and 5.5 in. Rated pressure 3,000 lbf /in 2 . Roof load capacity at rated pressure 142 st total at 3,000 lbf/in 2 . Contour-conforming roof support 2 (1 per side). Mine roof contact areas 18 (9 on each side). Av mine roof contact load pressure at cylinder capacity.... 260 and 140 lbf/in 2 . HYDRAULIC PUMP DRIVE 1,200-r/min water-cooled motors (3) 2, 60 hp; 1, 1,200 hp. PUMPS Roof drills (4) 30 gal/min per gear. Scrubbers (1) Do. Cylinders (1) to 37.6 gal/min per piston. Chain conveyor (1) 30 gal/min per gear. Hydraulic oil reservoir capacities (3) 2, 90 gal; 1, 120 gal. ROOF DRILLS (4) Feed rate (maximum) 26 f t/min. Torque (maximum) 300 ft'lb. Thrust (maximum) 8,000 lb. ROOF DRILL DRY DUST COLLECTION 4 blowers 70 ft 5 /min at 12 in Hg. Blower type Positive displacement , 2-rotor lobe type. Motors (2) 7.5 hp. Dust collectors 4 (1 per drill). Dust collectors type 3-stage: 2 centrifugal, 1 media-type filter. Manufacturer Donaldson (modified) . VENTILATION FAN (1) Type Electrically driven, axial flow, 2-speed. Capacity: High-speed 7,000 ft 3 /min, at 12 in H 2 0. Low-speed 3.7 hp at 3,600 r/min. Electric motor drive: High speeds 15 hp at 3,600 r/min. Low speeds 3.7 hp at 3,600 r/min. AIR SCRUBBERS (2) Type Centrifugal, wet impingement. Manufacturer T. J. Gundlach. Capacity 2,000 f t/min each. Water requirement 3 gal/min each. Roof contour conforming. Dust collector blower housing ^Ventilation air intakes Sumping cylinder 60° ypical )// 15' extended I3'4"retracted 14' tramming 10'extended 5' retracted Contour- conforming roof support Vent duct outlet Sumping cylinder Ventilation air intakes 80" max 30" min i 10 max height "-36" 6, " min nei 9 nt Roof drill dust collectors FIGURE 3.- Automated extraction system machine components. UMBRELLA MINER Objective FIGURE 4.-Typical mine plan and cut sequence for break-to-break mining with automated extraction system. To improve productivity and safety by developing a full-face raining machine that simultaneously extracts coal and bolts the roof within 8 ft of the face. Justification A major impediment in improving produc- tivity in room-and-pillar mining is the place changes between the miner and bolt- er, which occur about every 20 ft of ad- vance. These moves are costly in terms of lost production, machine wear and tear, and increased personnel hazards due to moving machinery. To satisfy the need for increased productivity and safety, Fairchild Research and Development, Inc., patented and developed the umbrella miner concept in 1976. When development funds became exhausted, government funding was secured in July 1981 to complete fabrica- tion. In August 1984, this machine was shipped to the Bureau for surface test- ing and evaluation prior to underground trials. Description This machine is designated the "umbrel- la miner" because the 20-ft-wide cutting head folds back around the side of the machine into two 10-ft sections, as shown in figure 6, reducing the miner width to 16 ft 10 in for easier tramming after each 100- to 200-ft advance. This ma- chine, with specifications as shown in table 3, is designed to operate in a 54- to 72-in coal seam. It is designed to 10 FIGURE 5. --Automated extraction system at Bureau's surface test facilities. Front pivot locked Bolter modules in tram position Pivot slide extended I7'2" Miner conveyor Possible bolter module positions FIGURE 6.-Umbrella miner with augers in tramming mode. FIGURE 7. -Umbrella miner straight-ahead mining. 11 *U>m>W.jilh>tfjii.uHliiflU|uA/WUWiaA 10- ft auger head — left and right GO SI m a SI 13 m 01 B IS 20 ® pi B El a a Bolter modules and temporary roof support crawler mounted (2 roof drills each) Front crawlers Front conveyor Miner cab s — Rear conveyor -Rear crawlers FIGURE 8.--Umbrella miner turning a crosscut. advance at least 100 ft with the con- figuration shown in figure 7, turn a 90° crosscut as shown in figure 8, and ad- vance at least another 100 ft before it moves to a new location. This machine consists of modules, as shown in figure 9, comprising augers, conveyors, and bolters. Roof bolting is accomplished with two manual roof drills mounted sepa- rately in each of two mobile crawler- mounted steel structures that include temporary roof support. Figure 10 shows that these bolter modules are independent of the miner and are connected only by an umbilical cord of hydraulic hoses, giving them flexibility to move sideways, for- ward, and backward in order to mount bolts on 4-ft centers. The minimum work- ing crew consists of one machine opera- tor, two roof bolters, and two utility persons behind each bolter to handle sup- plies and ventilation. Panic bars will be installed on the CM and bolters to protect the bolter operators from any potential hazards. Right cutter auger module Right bolter module Operator station Oil reservoir jj!>. .-&. .-<>■ .-Q-.. Lrj_rxj7r:i_LLi_i 0= J Left bolter module Left cutter auger module m CD J Electrical enclosure i 1^ r 34"min when mining 42 max when tramming 51' I /_ when mining ,L. 55' 3/" while tramming with augers in mining position lb 50'4 / " While tramming with augers in folded position FIGURE 9.--Major components of umbrella miner. 12 TABLE 3. - Umbrella miner specifications MACHINE ENVELOPE DIMENSIONS Overall machine length: Mining mode 51 ft 1-9/16 in. Extended pivot hitch 55 ft 3-1/16 in. Cutters folded, extended hitch 50 ft 4-3/16 in. Face to first pivot 17 ft 2 in. Mining width 20 ft. Tram width (cutters folded back) 16 ft 10 in. Weight 120,000 lb. Height (bolter module temporary roof support retracted).... 4 ft 4 in. Ground clearance to 6 in. Mining range 54 to 72 in. Mining capacity (6-ft seam) 1,152 st per unit shift, Roof bolt to face distance 8 ft. Roof bolters (2), crawler-mounted modules 2 bolters per module, bolts installed 4 ft to center. Machine horsepower (total) 560 hp. 140-hp electric motors (4 — 2 for cutterheads and 2 for 1,775 r/mirt, 950 V ac, hydraulic power supply). 3-phase. Coal cutting heads, 2, each 10 ft long: Bit tip-to-tip diameter 2 ft 8 in. Speed. 48 r/min. Shear height 6 ft. Sump depth (3- to 16-in increments) 4 ft. Below grade cut 2 in. 140-hp Louis Allis drive motors, 1 per head 1,775 r/min, 950 V ac, 3-phase. SUMP CYLINDER (2 — 1 PER CUTTERHEAD) Diameter 5-in bore, 3— in rod. Sump force at 1,500 lbf/in 2 29,452 lb. Stroke 4 ft 1 in. Sump rate 40 in/min. SHEAR CYLINDER (4 — 2 PER CUTTERHEAD) Diameter 7— in bore , 3— in rod. Force at 1,500 lbf/in 2 : Up 115,454 lb per head. Down 94,248 lb per head. Stroke 11 in. COAL HAULAGE CHAIN CONVEYORS (GATHERING, 2—1 PER CUTTERHEAD) Capacity 6 st/min. Speed 250 f t/min. Drive, hydraulic motors (2) 5 hp, 224 r/min. 13 TABLE 3. - Umbrella miner specifications — Continued FRONT-INBY UNIT Width 2 ft. Depth 7 in. Speed 438 f t/min. Capacity 11 st/min. Drive, hydraulic motors (2) 8 hp, 327 r/min. REAR-OUTBY UNIT Width 2 ft. Depth 7 in. Speed 440 f t/min. Capacity 11 st/min. Drive, hydraulic motor 15 hp, 327 r/min. CRAWLERS (4 PAIR) Front unit pair: Speed to 55 f t/min. Drive hydraulic motors (2) 40 hp. Ground pressure 28 lbf /in . Rear unit pair: Speed to 55 f t/min. Drive hydraulic motors (2) 40 hp. Ground pressure 13 lbf /in . Articulation 360° swivel. CRAWLER-MOUNTED ROOF BOLTER MODULES (2) Speed to 35 f t/min. Drive hydraulic motors (2) 15 hp. Ground pressure 11 lbf /ft . Roof drills per module 2. TEMPORARY ROOF SUPPORTS (TRS) JACKS (3 PER MODULE) Bore diameter 6-1/2 in. Rod diameter 5 in. Force at 850 lbf /in 2 each cylinder 28,205 lb. TRS roof contact pads , 7 per module 10-in diara. Hydraulic power supply 6 hydraulic circuits. PUMPS (4) Dynex single flow (2) to 60 gal/min. Dynex split flow (2) to 30 gal/min. DRIVE Electric motors (2) 140 hp each. 14 FIGURE 10. -Umbrella miner chain conveyor system. Status REMOTE OPERATING SYSTEM Surface testing of the first prototype unit of the umbrella miner concept (fig. 11) revealed that the concept has consid- erable potential for accomplishing the goal of continuous break-to-break mining; that is, mining and bolting the roof simultaneously. However, testing also revealed that this machine is not ready to be taken underground for testing and evaluation, a situation not unexpected for a first prototype device (15-16). Negotiations are under way with Fairchild to return the machine to its shops for additional modifications under a memoran- dum of agreement. Objective To provide greater operator protection by remotely operating a thin-seam mining machine 500 ft or more from the face. Justification The safety of underground workers can be dramatically increased by removing them from the coal extraction face. This is particularly true when a conventional, remotely controlled, thin-seam contin- uous miner (TSCM) is used, which normally requires an operator within 25 ft of the 15 FIGURE 11. -Umbrella miner in surface test facility. extraction face. Removal of TSCM opera- tors and their helpers from the hazard areas would also increase their comfort and reduce the incidence of associated health and congestion problems. It is extremely difficult to provide an operator's compartment with a canopy com- plete with safety provisions and human engineering on a CM designed for coal seams less than 42 in. One alternative that would provide maximum protection in thin seams would be to control the mining machine with a tethered cable or radio remote control so that the operator is out of sight of the miner and coal face. This approach allows available space to be fully utilized for protection and com- fort of the operator while providing full operational controls and displays. Re- moving mining personnel from the coal ex- traction face constitutes the first step in development of a worker-free mining system. The remote operating system (ROS) rep- resents the Bureau's initial effort in an area that holds great promise for signif- icantly increasing operator safety, al- lowing extended flexibility in selecting mining strategies, and expanding the re- covery of coal reserves. 16 Description system to supervise communications be- tween the operator station and the TSCM. An ROS will be retrofitted to a modi- A continuous face haulage system, also fied Jeffrey model 102HP TSCM (Jeffrey remotely controlled, will complete the Mining Machine Division of Dressor Indus- mining system. No roof bolting will be tries, Inc.). The mining system will be conducetd with this system. An ROS pro- composed of the remotely controlled miner totype is shown in figure 14, and the (fig. 12), a human-engineered operator machine specifications are given in table station (fig. 13), and an electronics 4. TABLE 4. - Specifications for remote operation of thin-seam continuous miner (TSCM) GENERAL Height (including cameras) (estimated) 3 ft 2 in. Length 23 ft 5 in. Width 9 ft 6 in. Ground clearance 5-3/4 in. Weight 44, 500 lb. Tram speed 60 f t/min. CHAIN CONVEYOR Width 2 ft 6 in. Depth 6 in. Speed 26 f t/min. COAL CUTTING Extraction width (single pass) 10 ft 1 in. Seam height 34 to 45 in. Auger diameter 2 ft 2 in. Auger speed 104 r/min. Sump advance 18 in. Sump speed to 6 f t/min. CONTROL SYSTEM Type Out-of -sight remote. Communications Computer-controlled via hard wire between operator compartment and continuous miner. Visual Two closed-circuit tele- vision cameras on miner transmit to monitors located within the remote operator compartment. Aural Sound and voice synthesizer. Other displays in operator compartment Temperatures, pressures, voltages, depth of sump, height of cutting head, etc. NOTE. — The remote operating system is designed to interface with a Jeffrey MMD mod- el 101 or 102 continuous miner. Therefore, many of the system specifications relate to the physical size of these two models. System specifications listed above apply to underground room-and-pillar deep mining and surface highwall mining as well. 17 FIGURE 12.-Continuous miner designed for remote operation. FIGURE 13-Artist's illustration of remote operator compartment. 18 b m* FIGURE 14.-Prototype remote operator compartment. Retrofitting to the TSCM includes the addition of two color television cameras, an explosion-proof housing containing the electronics package, and pressure, tem- perature, current, and linear displace- ment sensors. The electronics system will employ two microprocessor systems, the master system in the operator station and the other on the TSCM. Operator com- mands, video signals, and sensory data will be transmitted between the station and the TSCM over several small-diameter cables run alongside the standard power and water lines. Displays and controls will be located in front of the operator via an ergonomically designed operator workstation. Two color television moni- tors will provide visual input. An as- sortment of digital and analog displays will provide information pertaining to the operation and nonoperation of the miner, originating from sensors mounted on the TSCM. The operator will also be provided with two forms of aural com- munication: a microphone on the TSCM to transmit face sounds and a voice synthe- sizer to provide selected operational in- formation during periods of peak visual input. The operator will control the TSCM from a panel situated below the two monitors, which will allow the actuation of the same functions as those normally used to operate the TSCM via a tethered control box (17). The continuous face haulage system to be utilized in this system will be the Buereau-developed multiple unit contin- uous haulage system, which is covered in detail in a later section of this report. The underground cooperator has the re- sponsibility to make the haulage system compatible with the ROS of the TSCM. 19 Status Simulated coal cutting tests commenced at Bureau facilities in 1987. Negotia- tions are being conducted with a coopera- tor for coal extraction in a surface min- ing highwall operation with a general configuration as shown in figure 15. VARIABLE WALL MINER SYSTEM Objective To eliminate cyclic production delays of the CM system by combining cutting, conveying, and roof support into a single rotary machine with a face width up to 500 ft and production capacity approach- ing 5,000 st per shift. Justification The variable wall miner system (VWMS) is a relatively low-cost alternative for longwall mining. Other applications for the machine Include pillaring in room- and-pillar retreat mining and thin-seam applications. The VWMS, though novel, is perceived to be free of high development risk, because coal will be extracted by auger scrolling, which is considered ex- isting technology. Description The VWMS, as shown in the artist's drawing (fig. 16), is comprised of a string of side-cutting augers connected end to end and distributed across a coal face of arbitrary length of up to 500 ft, which are used to cut and transport coal along the face to a centralized output conveyor. Self-advancing roof supports (chocks or shields) are used to follow the advancing auger, as in longwall mining. The auger is articulated so that one or more segments may be engaged in cutting at any time as the coal is transported along the face by the screw action of the auger scroll (fig. 17). FIGURE 15.-Using remote operation for mining a thin seam in a surface mining highwall. 20 (-Refracting shield Sumping FIGURE 16. -End and plan views of variable wall miner system. FIGURE 17.-Surface-testing of variable wall miner system. 21 Figure 18 shows the auger isolated from the roof supports and labor crew by a shroud composed of metal and rubber to reduce dust exposure to the workers. The auger string articulation (figs. 19-20) is accomplished by use of heavy-duty uni- versal joints connecting auger sections together and sump cylinders that can be sequentially sumped to produce a "wave" motion of the auger string. The VWMS was patented by Letcher T. White under U.S. patent 3,524,680 on August 18, 1970. The original concept had an auger with a diameter of 56 in, a 500-ft-long string length made up of 40 auger sections, and shields used for roof support for operation in a coal seam of 56 to 78 in height. Horsepower require- ments were estimated to be 1,850 hp. A Bureau contract was awarded to Southwest Research Institute in 1976 to perform preliminary and detailed design, and to fabricate and surface-test a reduced- scale VWMS prototype unit (18-19). This work resulted in a successful surface test of the VWMS in a sulfur-compo- sition simulated coal block in 1981. The reduced-scale version (figs. 17, 21), had an auger diameter of 28 in, a string length of 40 ft, and a 10-in shear stroke for use in coal seams from 30 to 38 in. A complete listing of the specifications is shown in table 5. Status The results and conclusions of the surface-test cutting trials at Southwest Research Institute for the scaled-down version of the VWMS indicate that the machine has significant potential to im- prove productivity and safety. With a 28-in cutting orbit and 40-ft length, the VWMS was viewed by coal mining industry personnel during surface testing as a machine with many applications, espe- cially room-and-pillar retreat mining. Surface testing and evaluation have been proposed to improve reliability and es- tablish machine parameters. FIGURE 18.-End view of variable wall miner auger string. 22 Support bearing 15- in ID 25*4- in swing diam SIDE ELEVATION 14"—, 36-in OD auger welded to shaft 42-in cutting circlediam Shear cylinder Sump cylinder Floor plate (removed in plan view) Hydraulic and electrical passageway (not shown in plan view) Space for control valves /Auxiliary roof support jacks (hold plow onfloor during down cutting shear cycle) (2 per plow section at"A") Shear cylinder Sump cylinder retracted FIGURE 19. -Variable wall miner face assembly. BIDIRECTIONAL AUGER Objective To develop a more efficient and safer method for retreat mining by developing a machine for augering pillars, with a pro- duction capacity of 250 st per shift to maximize resource recovery. Justification The roora-and-pillar mining practice used in underground mining of coal recov- ers only approximately 50 pet of the coal available; the other 50 pet is left in place as pillars to support the mine roof for immediate mine stability and safety for mining personnel and, in the longer term, for prevention of subsidence on the surface where land use is such that sub- sidence cannot be tolerated. Where sub- sidence is permitted, some attempts are made to mine portions of or almost all of the pillars during a retreat mining mode. This is a dangerous operation because the mine roof is continually collapsing be- hind the miners and always poses a threat to them as the pillars are being rained out. Description The bidirectional auger (fig. 22) is a single-chassis unit supported by four steerable driving wheels. Two augers, each 4 ft in diameter and 10 ft long, are mounted across the machine frame, with one auger facing out the left side of the machine and the other the right side (bidirectionally). Each auger can be sumped 10 ft, and each is sumped and ro- tated individually into the nearest coal rib. The machine is 25 ft long, 13 ft 4 in wide, and 5 ft 5 in high and weighs 44,000 lb. Complete specifications are given in table 6. Figure 23 illustrates operation of the bidirectional auger in a mine. Figure 24 shows a typical mine ventilation plan for pillar extraction. 23 TABLE 5. - Variable wall miner system (VWMS) specifications Machine item or function Prototype, 28-in diara Original concept, 56-in diam Cutting orbit Section length Auger pitch Sump stroke Shear stroke Maximum sump joint angle... Maximum shear joint angle.. Sump production Shear production Shaft diameter Shaft thickness Universal joint, Koelling.. Rotary speed Sump-shear advance rate.... Do Sump-shear cycle time...... Sump-shear wave velocity... Sump cutting rate Shear cutting rate For a 500-ft face: Production time Clearance time Cycle time Production rate (270 min) Conveying power Cutting power Total power required in. , in. in. , in. , in. deg. • deg. ,st/section. st/section. , in. i in. i in. r/min. i in/r. in/s. s. f t/min. st/min. st/min. mm. , min. min. st/unit shift. .hp. .hp. .hp. 56 94 56 22 22 12.9 12.9 2.23 1.25 24 0.5 9.5 40 2 1.3 16.9 55.4 15.8 8.9 9.0 2.7 11.7 5,130 1,250 600 1,850 Each auger is cradled in a trough, which channels cut coal to the chain conveyor. The chain conveyor lies in the trough along the bottom of the auger miner for its full length. Each trough can also be sumped up to the rib so that a tubular gasket fastened to the end of the trough seats against the rib to minimize spil- lage. Coal, cut by sumping the cutting head into the rib, is carried to the cen- ter of the machine by the auger flight- ing, where it is discharged onto the chain conveyor. At the outby end (dis- charge end), the conveyor is elevated, enabling coal to be discharged into a shuttle car. To minimize float dust, water sprays located overhead on the end of each auger trough spray water downward at the borehole opening. Water sprays are also located on the outby end of the conveyor. Methane is ventilated from the borehole by fresh air blown into the borehole through the hollow stem of each auger. A pair of angled floor jacks for each auger stabilizes the machine by transmitting cutting head thrust loads into the mine floor. Four roof and floor jacks provide roof support during drilling. The auger miner is supported on four steerable wheels with foam-filled rubber tires. Each wheel is driven by a hydrau- lic motor through a planetary gear reduc- er. Two modes of steering are provided: four-wheel steer and crab steer. Four- wheel steer provides good mobility for turning corners from entry to crosscut. Crab steer allows the bidirectional auger to move from rib to rib, from borehole to borehole, while remaining parallel to 24 FIGURE 20,-Closeup view of variable wall miner auger. the rib. All functions of the auger miner are performed hydraulically. Pumps mounted to each end of a 150-hp electric motor provide hydraulic power. The auger miner is controlled remotely by a tethered cable (fig. 25) connected to the auger miner electrical system at any one of three connectors located at three corners of the machine. Steering, tramming, and tram speed are accomplished at the remote-control unit by movement of a joystick, lever. Status The bidirectional auger was tested underground at the Peabody Coal Co. 's Marissa Mine in Illinois from August 24, 1981, to June 11, 1982. During this tri- al period many breakdowns occurred and considerable redesign and rebuild were necessary. The machine drilled 304 holes and mined 1,520 st of coal with shift production ranging from 5 to 120 st per shift. Some success was obtained in 25 FIGURE 21.--View of partial auger string and connecting shafting. FIGURE 22.-Bidirectional auger prior to in-mine trials. 26 TABLE 6. - Bidirectional auger specifications GENERAL Overall dimensions: Length 25 ft. Width 13 ft 4 in. Height 5 ft 5 in. For shipping or installation, reducible to: Length 19 ft 7 in. Width 9 ft. Height 3 ft 3 in. Total weight 44,000 lb. Main frame 28,000 lb. Carriages 16,000 lb. Floor jacks: Bearing area per pad 63 in . Total bearing area 252 in 2 . Stroke 9 in. Load capacity per jack 14 st. Total load capacity 56 st. Locking mechanism Mechanical roof and floor jack. Roof jacks: Bearing area per pad 63 in . Total bearing area 252 in . Stroke 19-1/2 in. Load capacity per jack 13 st. Total load capacity 52 st. Locking mechanism Mechanical roof and floor jack. Roof and floor jack (concurrent) operations: Extend (full stroke) 13 s. Retract (full stroke) 8 s. Ground pressure 115 lbf/in . Ground clearance 10 in. Steering Selectable 4-wheel (optional 2-wheel front or rear). Required entry width for single-maneuver 90° turn... 16 ft. Brakes Spring applied-pressure release. Grade holding ability 36— pet slope (21°). Gradability 27-pct slope (15°). ANCILLARY EQUIPMENT Hydraulic system capacity 120 gal, water cooled. Dust suppression system Water spray at each auger troat and on conveyor discharge. Water requirements 5 gal/min at 60 lbf/in . Fire suppression system Dry-chemical discharge. Methane detection system Bacharach dual-channel monitor. Lighting 3 fluorescent area lights , 2 incandescent floodlights. Borehole ventilation (through hollow auger stems)... Roots blower 175 ft /min. POWER AND PERFORMANCE Pump motor, Louis Allis electrical, 150 hp contin- 440 V ac, 60 Hz, 200 kV'A, uous, 196 hp intermittent. 1,750 r/min. Auger pump, Sunstrand hydraulic, series 26, variable 100 gal/min at 3,000 lbf/in . displacement. 27 FIGURE 23. -Conceptual plan for partial pillar extraction with bidirectional auger. increasing coal recovery from pillars; the increase amounted to 2 pet. The ma- chine appeared to have potential for min- ing 250 st per shift or greater but was limited by sump rates. Lack of machine power, thrust capability, machine stabil- ity, and optimum cutter bit lacing were the major stumbling blocks. Despite some early setbacks, the bi- directional auger is still perceived by the Bureau to have significant potential to warrant additional modifications and surface testing to achieve the goal of improved productivity and reliability in retreat mining. COAL TRANSPORT TECHNOLOGY Haulage is one of the basic unit oper- ations of the coal mining cycle (cut- ting, loading, and haulage). There are three major types of haulage underground: (1) primary, which transports coal to the surface, (2) secondary, which transports coal from the section to the primary system, and (3) face haulage, which transports coal from the face to the sec- ondary system. Haulage from the coal face generally involves the shortest haul distance but has the greatest effect upon production. Shuttle cars are the major form of face haulage, and eliminating delays from the intermittent operation of shuttle cars offers the greatest pos- sibility for improving production. Face haulage accidents have been a major source of concern, second only to roof and rib falls in producing serious injur- ies and fatalities. Mine haulage systems must be designed to be safe, dependable, and flexible to cope with changing physical conditions in the mine; above all, they must be cost effective. Attempts to establish 28 FIGURE 24. -Typical ventilation plan for pillar extraction with bidirectional auger. continuous face haulage systems acceler- ated with the introduction of the CM (20- 27 ) . Chain and belt conveyors have been adapted to continuous haulage from the CM, beginning with the simple bridge systems, followed by extensible belts, bridge conveyor systems, and modular in- terconnected conveyors. The following is a summary of the projects the Bureau has undertaken to advance the state of the art of face haulage. HOPPER-FEEDER-BOLTER Objective To improve productivity by developing a multifunctional machine to minimize two- pass CM place changes by combining in one machine roof bolting, lump breaking, and a surge car to interface between a miner and a face haulage system. 29 FIGURE 25.~Bidirectional auger underground in an Illinois coal mine. Justification This machine was conceived to solve a variety of problems that limit productiv- ity of room-and-pillar mining systems: 1. The maximum instantaneous output of a CM is typically greater than the in- stantaneous haulage rate of the outby continuous haulage systems; the hopper- feeder-bolter (HFB) provides compatible surge capacity for the CM output and lev- els out the coal and rock input for the continuous haulage system. 2. Production delays occur when large pieces of coal or rock must be broken manually before being transported through a continuous haulage system; the HFB pro- vides an on-board lump breaker. 3. Production time is lost when a CM and roof bolter place-change; because the HFB can bolt beside a two-pass CM, the number of entry-to-entry place changes is decreased; entry-to-entry place changes are replaced with side-topside equipment changes in place. A two-pass continuous mining system using the HFB has many of the poten- tial productivity bolter. Description advantages of a miner- The HFB is a prototype multifunction mining machine that was conceived by the Bureau and designed and fabricated by the Engineered Systems and Development Corp. under Bureau contract J0333940. The HFB (fig. 26) consists of two crawler-mounted chassis: a hopper-feeder and a bolter (fig. 27), which are connected by a tele- scoping boom. The hopper-feeder chassis has the capacity to level out CM coal and 30 FIGURE 26.-Hopper-feeder-bolter in surface test facility. FIGURE 27.-Bolter module of hopper-feeder-bolter. 31 rock surges from 12 to 7 st/min, and a lump breaker near the tail end crushes against a universal chain conveyor. The conveyor on the outby end has a 45° in- clined heavy-duty swing tail boom that transports coal to the next stage of haulage. The bolter chassis contains two manual mast-type bolter assemblies. Specifications for the HFB are presented in table 7. Figure 28 shows components of the HFB. The hopper-feeder chassis can be oper- ated from two locations: (1) The main control panel, consisting of a single row of toggle switches, is located on the right side of the hopper-feeder and is used to operate all functions, and (2) a remote-control handheld unit (fig. 29) is available for the machine, which can be used to operate all major functions except bolting. The sequence of operator-and-machine movement for the HFB and a CM are presented in figure 30. This sequence could be used with either intermittent or continuous face haulage methods. The sequence was designed to achieve the following objectives: (1) keep personnel from entering under unsupported roof, (2) keep personnel from passing between moving equipment and the mine rib, (3) keep the bolter module at least 10 ft from the miner cutterhead, and (4) keep the HFB hopper as close as possible to the miner discharge boom (28-30) . Al- though the raining system is designed to keep the bolter module at least 10 ft from the miner cutterhead, panic bars will be installed on the two-pass CM adjacent to where the bolter operator would be working. These panic bars, which are activated by touch, will shut the mining machine down and protect the bolter operator from any unexpected haz- ardous situation. Optional bolter module assembly Boom traverse drive motor Pump motor Main control panel Hydraulic reservoir Secondary dust collector _ box and vacuum pump/~ Lonve y° r motor 9'7" 2-drill-head roof bolter Conveyor swing cylinder Tram motor Conveyor elevation cylinders PLAN Temporary roof support cylinders -nS- Breaker motor Breaker speed reducer maximum extension ELEVATION FIGURE 28.-Major components of hopper-feeder-bolter. Not to scale 32 TABLE 7. - Hopper-feeder-bolter (HFB) specifications (Overall machine length: 48 ft 8 in with boom fully extended) CHASSIS Power 460 V ac. Height 4 ft. Width 9 ft 7 in. Length 26 ft 9 in. Weight 49,500 lb. Crawler tracks (2) 16 by 84 in. Tram motors (2) 21 hp each, 220 V dc. Tram speed (SCR controlled) to 90 ft/min. Breaker motor 100 hp , 460 V ac. Pump motor Do. Hopper capacity 191 ft . Chain conveyor 30 in wide, variable-speed and 2-direction, center strand, heavy-duty rock chain. Tail boom Variable swing and elevation. BOLTER MODULE Power Hydraulic and intrinsically safe. Height: TRS fully extended 8 ft. TRS retracted 4 ft. Boom extension capability 5 ft 5 in. Weight 7,000 lb. Crawler track 11 by 36 in. TRS loads 12,000 lb at 500 lbf/in 2 . Drill heads (2) spacing 4 ft. Drill torque (adjustable) To 275 fflb at 2,000 lbf/in 2 . Drill speed (adjustable) To 325 r/min. Drill thrust (adjustable) To 7,000 lb. Vacuum dust collection 3-stage. SAFETY Emergency stop switches (ribbon type)... 9. Fire suppression Water sprays. Dust suppression Do. SCR Silicon control rectifier. TRS Temporary roof support. Status After successfully completing surface test trials, the hopper-feeder portion of the HFB, which includes the surge car and lump breaker, was combined with the mono- rail bridge conveyor (a Bureau-developed face haulage system, described later in this report) to form a continuous face haulage system. The system was tested underground and proved the concept that coal can be transported from the CM on a monorail system attached to the mine roof with the hopper-feeder serving as a surge car and lump breaker. 33 Subsequently, the hopper-feeder was used by the Consol Pennsylvania Coal Com- pany to design a similar type vehicle to interface between the company's continu- ous face haulage system and miner-bolter. Testing and evaluation will commence in the summer of 1988. There are no plans to take the optional manually operator bolter module under- ground. Long-range plans include operat- ing the bolters remotely in conjunction with the hopper-feeder. -20' 2- pass CM — \ Exhaust X, Tubing or ', brattice- tSI HFB 1_T Bolter module -CM trailing cable -HFB trailing cable HFB HFB U3 H KEY CM HFB E3 Unbolted roof ■ Miner operator ♦ HFB chassis operator • Inside bolter operator * Outside bolter operator FIGURE 29. -Hopper-feeder-bolter handheld remote control unit. FIGURE 30.~Operating sequence of hopper-feeder-bolter (HFB) beside a two-pass continuous miner (CM). 34 MONORAIL BRIDGE CONVEYOR Objective To develop a cost-efficient continuous face haulage system suspended from the mine roof to improve productivity and health and safety. Justification The primary bottleneck preventing in- cresed production in room-and-pillar min- ing sections is the inability of inter- mittent shutte car haulage to keep pace with the CM, especially in mines with bad bottom conditions. The monorail bridge conveyor (MBC) system has the potential to improve productivity by eliminating shuttle car changeout times; the MBC pro- vides a captive guidance system that requires only one operator, regardless of length, and allows haulage in poor bottom conditions where conventional rubber-tired shuttle cars do not operate efficiently. In regard to safety, the MBC is an improvement over conventional systems because it eliminates the poten- tial for accidents involving shuttle car trailing cables and moving vehicles. Description The MBC consists of a series of cascad- ing belt conveyors supported by an in- verted T-section monorail bolted to the mine roof. The basic concept was con- ceived and patented by the Bureau in 1979 (U.S. patent 4,157,757). It was designed and fabricated by the Goodman Conveyor Co., Inc., under a cost-sharing arrange- ment with the Bureau (contract J0333917). The three types of MBC units (the inby, typical intermediate, and outby) are shown in figure 31. Each conveyor unit consists of a belt conveyor mounted on a rigid frame, monorail suspension hard- ware, a monorail-mounted tram unit, and electric power and control components. Some of these components are shown in wmmmmmmmmmmmmmmmmmmm ^mm ^^^^^^"'Hr^ ^lg^t Inby unit l .il.-: ;%>*. J wm/// m/mmm/m///mi//mfmjmMm //mm//mm///,} a^^ Intermediate unit wm/m/M mmmmmmf/mm^gm^^ ^^^ (^EE gto^i^^llp^^^f= i ^n^ r = i3J _i JL Outby unit FIGURE 31. -Three types of monorail bridge conveyor units. 35 figure 32. All MBC units are totally monorail suspended except for the inby and outby units. The inby end of the inby unit (fig. 33) is mounted on rubber tires that can be steered remotely. The outby end of the outby unit can be supported either by a dolly mounted on a rigid belt structure or by monorail that is directly over the section belt. A complete listing of the specifications is given in table 8. Tail roller Return idler \ Belt sequence switch Belt si ip switch Motor control case J [ Head roller Belt takeup mechanism Troughing idler 10 -hp electric motor V Coupler Gear-speed reducer •*- Inby Note: Belting not shown Outby FIGURE 32.-Plan view of monorail bridge conveyor unit. FIGURE 33.-lnby unit of monorail bridge conveyor. 36 TABLE 8. - Monorail bridge conveyor (MBC) system specifications SYSTEM SPECIFICATIONS Nominal haulage rate 600 st/h. Length (13 conveyor units) 1 312 ft. Constant tram speed on monorail 60 ft/min. Power 460 V ac. Control circuit 120 V ac. Total conveying power (13 units) 130 hp. Total tramming power (13 units) 20 hp. Control of all units Single operator. 24-ft-radius monorail track Designed for 60° crosscuts. Compound curve Designed for 90° crosscuts. Minimum recommended entry width 14 ft. Monorail suspension On 4-ft centers. Typical maximum load on suspension point 2,000 lb. Monorail weight 7 lb/ft. Monorail lengths available 7 and 10 ft. Minimum working height 4 ft. Working height over low belt structure in belt 4 ft 6 in. entry. Maximum recommended gradability 6.5 pet. Inby unit support Remotely steered rubber tires. INDIVIDUAL BRIDGE SPECIFICATIONS Overall length 27.6 ft. Active length 24 ft. Overall width 7 ft. Carrier idlers on 25° angle 4-in diam. Conveyor belting: Width 3 ft. Speed (constant) 400 ft/min. Head and tail rollers 7-in diara. Tram drive motor on each unit 1.5 hp. Conveyor motor on each unit 10 hp. Weight of each unit (empty) 4,200 lb. SAFETY FEATURES Belt Slip and sequence switches. Disk brakes Automatically engage on each tram unit drive when tram power is shut off. Emergency stop On each unit. Pendant control From any unit. End-of-monorail stop On inby bridge unit. Warning horn Before belt conveyor(s) startup. Electrical interlock System with panel belt conveyor. Expandable to greater length. Controls for steering, tramming, and conveying are located on an umbilical pendant control. The pendant control (fig. 34) may be connected to any unit in the system for convenience and allows operator positioning to avoid blind or unsafe MBC operation locations. Both ends of each conveyor unit are supported by eight-wheel carrier as- semblies (fig. 35) that distribute the 37 FIGURE 34.--Pendant control for monorail bridge conveyor. Carrier Track with splice p FIGURE 35.--Monorail hardware. weight of each conveyor on the light- weight monorail track (fig. 36). The carriers are designed to follow both vertical and horizontal curves in mono- rail track without affecting conveyor suspension. 38 H 14' Right switch Leftswitch Monorail track section 10' ! -, J) 7' L 9' 5 '|6 ^'/z" MK-I, MK-2, MK-6, MK-3, ^K-5, straight straight straight left right curved curved MK-4, curved Note: All curves on 24-ft radius FIGURE 36.-Monorail track. Miner operator H Foperator — / — ■^—^Mine-HF cable handler « < ~1 » Operator fe 1 2 -pass continuous miner HF / ,nbyunit Monorail track —80' FIGURE 37, --Monorail bridge conveyor used with hopper-feeder (HF). Even though the inby MBC unit can be loaded directly by a CM, it would be desirable, in most cases, to include surge and breaker capabilities between the miner and the MBC. This function can be best performed by the hopper- feeder, which is a portion of the hopper-feeder-bolter (HFB) (described in this report), as shown in figures 37 and 38, interfacing between the inby unit of the MBC and the miner. The MBC has a variety of applications: It can be used for room-and-pillar raining (fig. 39), longwall panel development te BfMWtWlltr i l * llB^I»Wii.anvtYirtlnfnir.,».^Kd;,\ ;/, ,y,..v ,„.>,, .w/^/tw.v >-, .1,, HF tail boom 62" min Hopper of inby unit FIGURE 38. --Monorail bridge conveyor interface with hopper-feeder (HF). 39 Continuous miner Hopper-feeder surge car 1 2- unit system Monorail track FIGURE 39.-Monorail bridge conveyor mine plan for room-arid-pillar mining. (fig. 40), or shortwall mining (fig. 41). Surface testing has confirmed that the MBC can negotiate a 90° crosscut ( 18 , 31- 34). Status After successfully completing surface test trials, the MBC was combined with the hopper-feeder to form a continuous face haulage system that was tested underground in a midwestern coal mine. Test results proved the concept that coal can be moved from the face in a roof- supported monorail system. Figure 42 shows the MBC outby unit installed over a section belt underground. 40 Panel belt Belt Intake Return Monorail bridge \m nMr „ii tr „^ conveyor Monorail track 60° (typical) Not to scale FIGURE 40. --Monorail bridge conveyor mine plan for longwall panel entry development. mm mm Panel belt conveyor Monorail bridge conveyor Continuous miner mm l_j 1 ■' ■ •* n i - ' ■ „ Chock FIGURE 41. -Monorail bridge conveyor used with shortwall mining system. ,.-■ '.• MULTIPLE-UNIT CONTINUOUS HAULAGE SYSTEM Objective To improve productivity and safety in room-and-pillar mining by developing a continuous, self-tracking, rubber-tired face haulage system to reduce the in- efficiencies of conventional shuttle car haulage systems. Justification Continuous face haulage can be an at- tractive alternative to shuttle car haul- age in underground room-and-pillar coal mining and particularly in thin coal seam deposits. Continuous haulage allows the mining machine to mine more coal by avoiding the wait for shuttle cars to move into a loading position behind the miner. Continuous haulage systems are 41 FIGURE 42.-Monorail bridge conveyor underground installed over a section belt. also inherently safer because accidents involving fast-moving shuttle cars are eliminated. An important aspect of any continuous haulage system is the ability of each segment of the train to follow in the same path as the preceding segment. The system length, which generally ex- ceeds 250 ft, requires a retracking sys- tem that is accurate and reliable to re- duce interference and guarantee safety. Description The MUCH system (fig. 43) was designed and manufactured by Jeffrey MMD under Bu- reau contract J0333941 (35). Each MUCH vehicle has a chain conveyor mounted on a transporting vehicle that has four-wheel steering and two-wheel drive. The vehi- cles are connected by a unique mechani- cal self-tracking steering system (U.S. Patent 4,382,607), as shown in figures 44 and 45, which connects adjacent vehicles into a train with automatic mechanical tracking and retracking. Coal cascades from conveyor to conveyor down the vehi- cle train from the face at a maximum rate of 12 st/min. The train of vehicles is steered by the operator in the lead vehi- cle (fig. 46), which follows the contin- uous mining machine; limited steering capability is also provided on the 42 Section belt or chain structure Lead vehicle operator Continuous miner Discharge vehicle operator FIGURE 43. --Multiple-unit continuous haulage system. Steering bar -1 Hopper Drawbar Tie rods 8.25 by 15 tires Vehicle B Vehicle A FIGURE 44.-Vehicle-to-vehicie mechanical linkage steering subsystem for multiple- unit continuous haulage. A3 FIGURE 45.--Multiple-unit continuous haulage undercarriage showing installation of mechanical linkage steering subsystem. FIGURE 46.~Lead vehicle of multiple-unit continuous haulage system. discharge vehicle to keep the vehicles parallel to the panel belt. The mechani- cal steering linkages on each vehicle en- able all the vehicles to sequentially track the path of the preceding vehicle through a mine at 80 ft/min. A complete listing of system specifications is given in table 9. The MUCH system includes three types of vehicles: Each train (system) consists of 1 lead vehicle, intermediate vehicles (10 currently available), and 1 discharge vehicle with a bridge conveyor. Inter- mediate vehicles can be added or removed from the train to suit the section mining requirements. The length of the 12-unit 44 TABLE 9. - Multiple-unit continuous haulage (MUCH) system specifications (System: 460-V-ac power, 120-V-ac control; 18-ft-wide entries and crosscuts; 60° or 90° crosscut angles; 24-ft minimum turning radius; 60-in minimum working height; 115,250-lb estimated total 12-unit system weight) Lead vehicle Intermediate vehicle Discharge vehicle Frame length Bridge conveyor: Active length. . . . Height Width Canopy adjustment.. Conveyor chain: Speed Width Trough height Motor Capacity Tram: Speed Motor Wheel size Tread width Brakes Drive. . . ■ Steering. Communication. Hydraulics : Pump Motor Headlights : Number Voltage 23 ft 3 in. 19 ft 9 in. . 3 ft 5 in... 6 ft 6 in. . . 42 to 56 in. 280 ft/min. 30 in 9 in 15 hp 12 st/min. . 80 ft/min , 7.5 hp , 8.25 by 15 , 5 ft Disk, hydraulic. Front wheel , Forward — manual ; rearward — automatic. Page phone , 1 unit 1 hp. 11 V ac. 21 ft 9 in. 19 ft 9 in, 3 ft 5 in.. 6 ft 6 in. . NAp 280 ft/min. 30 in 9 in 15 hp 12 st/min.. 80 ft/min 5 hp 8.25 by 15 5 ft Spring activated, power released. Front wheel Automatic Optional on 1 unit.. NAp, NAp, NAp, NAp, 21 ft 9 in. 19 ft 9 in. 3 ft 5 in. 6 ft 6 in. NAp. 280 ft/min. 30 in. 9 in. 15 hp. 12 st/min. 80 ft/min. 7.5 hp. 8.25 by 15. 5 ft. Disk, hydraulic. Rear wheel. Forward — automatic Page phone. 1 unit. I hp. 2. II V ac. NAp Not applicable. NOTE. — Although the MUCH system was designed for use in underground roora-and-pillar coal mines, it may also have application to surface highwall mining. system with the bridge conveyor is 250 ft. A typical mining plan, shown in fig- ure 43, depicts the system turning a 90° crosscut. The intermediate vehicle (fig. 47) con- sists of a vehicle frame, a chain convey- or, conveyor and tram electric motors, a permissible electric control enclosure, and steering and tracking linkages. The lead vehicle (fig. 48), in addition to having the same equipment as the in- termediate vehicle, contains an ad- justable protective enclosure for the operator on one side of the vehicle with- in the wheelbase, which contains hydrau- lics for steering and hopper movement. The receiving hopper of the lead vehicle is extended by 18 in to reduce the fre- quency at which the train must be jogged to follow the CM discharge conveyor boom during the mining cycle. The discharge vehicle, shown in figure 43, is similar in design to the inter- mediate vehicle. The important differ- ence is that the discharge vehicle car- ries two chain conveyors: One chain FIGURE 47. -Intermediate vehicles of multiple-unit continuous haulage system. FIGURE 48.--Protective enclosure for multiple-unit continuous haulage lead vehicle. 46 conveyor mounts on the vehicle frame, as on the intermediate vehicle, and a second chain conveyor hangs on top of the rear of the discharge vehicle and bridges it to a dolly riding on the panel haulage belt. A second operator steers the rear wheels of the discharge vehicle to pre- vent it from drifting into or away from the main haulage belt ( 18 , 35) . Status After completing surface testing and evaluation, the MUCH system will be used in a highwall mining operation. It will be operated remotely, with cables up to 250 ft from the operator station, in com- bination with the remote-control miner (discussed in this report) to extract coal in a highwall mining operation. AUTOMATED BRIDGE CONVEYOR TRAIN Objective To develop an advanced continuous haul- age system with automatic guidance, capable of operating in typical room-and- pillar mine configurations using a mini- mum of personnel. Justification Continuous haulage would be used more extensively except that systems currently available place even more constraints on the mining operation than do shuttle cars. Place-changing with currently available continuous face haulage systems is time consuming because the movements of all components must be carefully co- ordinated; simultaneous tramming of all units is more difficult using manual con- trols. Sections with continuous haulage are generally limited to three entries because the addition of more haulage units (to give longer reach) may increase personnel requirements. Additional units also increase the complexity of equipment tramming during mining. One alternative to remedy the difficul- ties described above would be to employ an automatic guidance system. This is one of the first steps required for development of a totally automated mining system. Description The automated bridge conveyor train (ABCT) is a series of mobile bridge car- riers and bridge conveyors equipped with an automatic guidance system, as shown in figure 49. It was designed and partially fabricated by Foster-Miller Associates, Inc. , under Bureau contract J0333913 (36) . With only one operator, an ABCT up to 500 ft long can track precisely along a guidance cable. This cable is laid down by the inby carrier employing a microprocessor-controlled guidance system that allows system operation with a mini- mum of operators. As the train travels, each successive carrier centers itself about the cable, as shown in figure 50, through the use of cable sensors and an on-board computer. The cable can be laid down and retrieved automatically by the lead vehicle as it follows behind the CM. A complete listing of the specifications is given in table 10. The system is ca- pable of operating with only one operator located at the outby vehicle. Other advantages include the following: 90° crosscuts can be negotiated (fig. 51), proven hardware is employed for the bridge and conveyor mechanisms , and no special minesite preparations are re- quired for the guidance system. Status The current objective of the in-house program is to complete fabrication of the system, perform system evaluation and re- liability testing through surface trials and make modifications as needed, and locate a cooperator for long-term testing and evaluation. To date, the inby unit (fig. 52) is 90 pet complete, and limited surface trials indicate that the system, when completed, will have significant potential to increase productivity and safety. 47 "•-Coal face Receiving hopper Section belt-*- Guidance cable Mobile bridge carrier Guidance cable Extensible piggyback bride conveyor Guidance cable End of continuous miner tail boom Cable signal sensor (not shown) FIGURE 49.~Automated bridge conveyor train. FIGURE 50.-Automated bridge conveyor train centering itself about guidance cable. 48 Extensible piggyback bridge conveyor Mobile bridge carrier FIGURE 51. -Typical room-and-pillar mine plan for automated bridge conveyor train. TABLE 10. - Automated bridge conveyor train (ABCT) system specifications [System: 276 ft (5 units fully extended plus bridge conveyor); 960-V-ac, 3-phase, 60-Hz power; 7-ft 8-in maximum vehicle width; 175,000-lb estimated total system weight. Mine plan: 16-ft-wide crosscuts (minimum), 60° or 90° crosscut angles on 60-ft centers, 44-in minimum working height] Conveyors: Width 2 ft 6-1/2 in. Depth 5 in. Speed 276 f t/min. Capacity 8 to 12 st/min. Motor 30 hp, 960 V ac. Tram: Type 4 drive wheels per ABCT carrier unit. Speed 24 to 50 f t/min selectable. Motor 75 hp each, 960 V ac, electrohydraulic stepper type. Steering: Inby vehicle Controlled by operator via pendant. Other vehicles Automatic tracking of signal cable paid out by inby vehicle. Guidance cable No. 8 AWG single conductor, 0.47-in OD, 5 or 10 kHz, 0.5-A current capacity. 49 FIGURE 52.~lnby unit of automated bridge conveyor train undergoing surface tests. FLYWHEEL-POWERED SHUTTLE CAR Objective To increase productivity and improve safety in underground coal mines by de- termining if flywheel-powered technology, applied to shuttle cars, could provide a reasonable alternative to the conven- tional shuttle car powered by an electric trailing cable. Justification Conventionally powered shuttle cars use ac or dc supplied in a trailing cable to an electric drive motor. The use of trailing cables in underground coal mines limits the number of shuttle cars that can be used in a working section. More- over, the trailing cable restricts the route that a shuttle can travel to and from the face, thereby making its use extremely cumbersome and intermittent, which limits the productivity of a CM. The use of trailing cables also poses a number of safety hazards such as electri- cal shock from deteriorated cables and the danger of tripping. The more conventional means of provid- ing power, such as the internal combus- tion engine, are not permissible in some States because of the closed environment. Flywheel power is especially suited for use in hazardous areas because it elimi- nates the need for an electrical trailing cable. (It has also been used in some military applications.) A flywheel-powered shuttle car poten- tially permits the use of a number of such cars in a section to improve produc- tivity and increase safety while freeing them from restraints inherent with use of the trailing cable. 50 FIGURE 53. --Flywheel-powered coal mine shuttle car. FIGURE 54.-Seven-rotor flywheel for flywheel-powered coal mine shuttle car. Description The flywheel-powered shuttle car (FPSC) (fig. 53) was designed and fabricated by the Engineered Systems and Develop- ment (ESD) Corp. under Bureau contract J0333911 (37-39). Several subcontracts were let by ESD to obtain essential spe- cialized technology, one to Rockwell In- ternational, Inc. , to construct the first rv 60 - 1 1 1 Haul, - 50 — Tram, l,890W-h ™" "" I 40 300 W-h — / -~ „ Tram r (Z 480 UJ W-h O 30 — — Q_ Load, 130 W-h 20 — Wait -L 10 - Parasitics 990 W-h 1 1 1 100 200 TIME.s 300 400 FIGURE 55. -Mission duty cycle of flywheel-powered coal mine shuttle car. seven-rotor flywheel (fig. 54), and one to Lear Seigler, Inc., to construct a constant-voltage generator (270 V dc) that could function at the flywheel high 51 speed (16,700 r/min). A combination of field data and computer simulations indi- cated that typical energy requirements for the mission duty cycle would be 3.8 kW-h (fig. 55). This unique flywheel drive system con- sists of seven rotors, each 23 in. in diameter, chat. rotate up to a maximum of 16,700 r/min and are encased in a near- vacuum (1-Torr) chamber measuring 28 by 34 by 76 in. The flywheel assembly is coupled to a voltage generator, which produces 270 V dc to power the shuttle car. Enough energy can be generated from the flywheel system to power the shuttle car through one typical duty cycle each time the flywheel system is charged up (spun up) to its full capacity from an off-board charging station. The flywheel module chosen to meet this energy requirement and still fit within the limited space available on a standard shuttle car was a compact seven-rotor module (fig. 56). This module is capable of storing a total of 6 kW*h of energy at 16,700 r/min, with A. 5 kW*h of usable energy, which permits the car to complete the duty cycle with 0.9 kW*h of energy in reserve (fig. 57). Specifications for the flywheel power system, shown in fig- ure 58, are detailed in table 11. Table 12 is a comparison of the FPSC with other haulage equipment in its class. Status The FPSC has been designed and fabri- cated and is undergoing comprehensive shakedown surface testing at the Bureau, which has resulted in modifications to correct deficiencies. Test results indi- cate that the flywheel package produces enough energy to power the shuttle car through a typical duty cycle. Flywheel acceleration transmission Oil heat exchanger Vacuum pump Oil pump Oil reservoir Brake ring Air circulation fan Rotor assembly Output generator FIGURE 56.-Energy storage system for seven-rotor flywheel of flywheel-powered coal mine shuttle car. 52 TABLE 11. - Flywheel-powered shuttle car (FPSC) specifications FMC MODEL 6L SHUTTLE CAR Total weight of car with flywheel drive package 30,000 lb. (empty). Overall length 24 ft. Height: Frame 2 ft 10-1/2 in. Top of canopy 4 ft 2 in. Minimum working height for cab with canopy 4 ft 8 in. Width 9 ft 4-1/2 in. Conveyor width 4 ft 8 in. Conveyor speed 64 f t/min. Capacity: Level 186 ft 3 . With 6-in side boards 272 ft . Tram speed Up to 4.2 mi/h with SCR control. Tire size 10:00 by 15; load rated at 16,000 lb each. Ground clearance 7.5 in. Wheel base 8 ft 2 in. Boom extension 3 ft 5 in. Clearance up 2 ft 11-1/4 in. Clearance down 10-1/4 in. Turning radius: Inside 9 ft 1 in. Outside 21 ft 5 in. Motors (250 V dc) : Traction (2) 15 hp. Chain conveyor 15 hp. Hydraulic pump 15 hp. 6-kW-h FLYWHEEL DRIVE Maximum gross energy storage at 16,700 r/min 6 kW*h. Net usable energy (16,700 to 6,500 r/min) 4.5 kW'h. Weight of flywheel drive to exclude onboard charge 3,250 lb. system. Onboard charge motor 300 hp , 480 V ac. Lubrication-cooling system 34.6 gal/rain at 230 lbf/in . Vacuum pump pressure in flywheel housing: Minimum 0.2 lbf/in 2 . Maximum 0. 02 lbf/in . Power generator from flywheel rotor 270 V dc. Flywheel rotor size 7 rotors by 23 in diara. Flywheel housing size 27.5 in diam by 45 in long. Flywheel drive space envelope 28 by 34 by 76 in. SCR Silicon control rectifier. FLIP-TOP CANOPY leanout-related accidents while providing a clear line of vision. Objective Justification To develop a new canopy for protecting shuttle car operators in low coal from In seam heights less than 48 in, pre- roof falls, pinching and squeezing, and vious attempts to apply current canopy 53 FIGURE 57.-Energy used in duty cycle of flywheel-powered coal mine shuttle car. technologies proved inadequate. Typical problem areas include visibility and operator fatigue caused by unusual and cramped operator positions. To overcome these objections, the Bureau devised a new and unique concept for high-speed face equipment in the 30- to 48-in seam height range by providing partial protec- tion and clear vision for shuttle car operators in the direction of tram. The canopy then swings over 90° to provide partial protection and clear vision when tramming in the opposite direction. Description A flip-top canopy (figs. 59-61), which provides increased safety and good visi- bility, was designed, fabricated, and retrofitted by the Bureau to an FMC 6L-48 end-driven shuttle car. The flip-top canopy is a quarter-circular design with a 25-in radius, constructed of 2. 5-in-OD high-strength steel tubing with 0.75-in 0.250diam 0.375diam 0.5gal/min O.Ogal/min 4.6gal/min 200lbf/in 2 _ Alternator Flywheel Hydraulic motor £3- 5.9gal/m 1601b f/i Pressure regulator, 17. 3gal/min < — i f^t^J Vacuum pump is 2 0.75diam 5.5gal/min High- speed gear box 230-lbf /in2 setting I I I I __L25Q.dJ.qm_ 1 Cooler 1 8lbf/in' Level gauge C ^50i a ff'^_ Hydraulic pump 34.6gal/min 3.IOO r/min 230lbf/in 2 /K. I.250diam Filler vent j j Dipstick i i Reservoir o Accessory gear box I.500 diam Fan Filter 8lbf/in 2 6.8gal/min I00lbf/in 2 (ga) Low- speed gear box 300-hp charge motor Hydraulic motor -Q- 6.8gal/min 0.750diam FIGURE 58.-Power system of flywheel-powered coal mine shuttle car. 54 TABLE 12. - Comparison of various face haulage vehicles Vehicle type Stored energy. kW'h Duty cycle, kW-h Total onboard Pay load (water level) ft st Total weight (empty), lb FMC 6L-56, flywheel powered... FMC 6L-56, electric trailing cable FMC 6L-48 , Joy 18SC-13 , NMSC T-20, Torkar , NMSC MC-36-S12 , Jeffrey 404L, RAMCAR, battery, Kersey 16-S , 6.0 NAp NAp NAp NAp NAp 70 77 3.8 3.8 NAp 3.95 2.07 NAp NAp NAp 60 60 60 55 45 100 50 40 186 186 160 190 154 194 134 110 5.1 5.1 4.4 5.2 4.2 5.3 3.6 3.0 30,000 24,000 22,000 26,000 23,000 28,000 27,000 23,000 NAp Not applicable. Includes onboard 300-hp, 480-V-ac charge motor, gearbox, and shafting, which weigh approximately 2,750 lb. FIGURE 59.-Flip-top canopy, side view. 55 FIGURE 60.~Flip-top canopy, rear view. FIGURE 61. -Flip-top canopy, front view. 56 steel plate. The canopy unit (fig. 62) is supported on and rotated by a 1.5-in, 90-k.ip/in 2 tool steel shaft. A complete set of specifications for the canopy and shuttle car is given in table 13. The top is rotated 90° by means of a 10,000 in»lb, 1,600-lbf /in 2 rotary actuator. The flip-top actuator control (fig. 63), is in a protective box outside of the operator compartment to prevent acciden- tal activation of the canopy with the operator inside the cab; however, it is conveniently located for easy access wher changing tram direction. The operator compartment utilizes a fully adjustable, sling-type seat, which is flipped and moved from one side of the compartment to the other when changing tram direction (figs. 59, 64). This pro- vides increased operator comfort and im- proved access to the control pedals. The seat may be raised or lowered by tighten- ing or loosening the sling. TABLE 13. - Specifications for shuttle car and flip-top canopy operator compartment SHUTTLE CAR Weight (empty) 22,000 lb. Overall length 24 ft. Frame-chassis height 2 ft 11 in. Working height 4 ft. Overall width 8 ft 11 in. Chain conveyor width 4 ft 7 in. Chain conveyor speed 64 f t/min. Haulage capacity (water level) 160 ft . Maximum tramming speed 4.2 mi/h. Tire size 10:00 by 15. Ground clearance 7.5 in. Wheelbase 8 ft 2 in. Boom vertical travel 3 ft 5 in. Turning radius: Inside 9 ft 1 in. Outside 21 ft 5 in. Motors: Traction (2), 250 V dc 15 hp. Chain conveyor 15 hp. Hydraulics 15 hp. FLIP-TOP CANOPY OPERATOR COMPARTMENT Height (ground to top of canopy) 3 ft 8 in. Canopy width 3 ft 3 in. Canopy length 4 ft 11 in. Canopy coverage 25 by 34 in. Seating width 20 in. Flip-top mechanism adjustment time, 90° arc 3.5 s. 57 FIGURE 62.-Flip-top canopy showing head and leg room. FIGURE 63.--Flip-top canopy actuator control. 58 Status The flip-top operator compartment has been constructed and installed on the FMC 6L-48 shuttle car and is currently under- going performance evaluation at the Bu- reau's surface test facility. It is an- ticipated that the technology developed during the course of this project will be used to increase the safety and effi- ciency of mine equipment operators. A Bureau Report of Investigations on the design and construction was published in 1988 (40). FIGURE 64.-Flip-top canopy sling-type seat. COMMERCIALLY AVAILABLE BUREAU- SPONSORED TRANSPORT PROJECTS The following is a selection of com- pleted Bureau projects that are available commercially to the mining industry. Maximum-Capacity Shuttle Car Under a cost-sharing arrangement, a new design for a maximum-capacity shuttle car was developed jointly by the Bureau and National Mine Service Co. (NMSC) (1976- 82). The prototype vehicle was tested underground in a West Virginia coal mine (41). The first commercial version of the car was sold to a potash mine in New Mexico. Figure 65 shows the first pro- totype shuttle car, model MC-36. The de- sign is now commercially available from NMSC. Diesel-Powered Face Haulage Vehicle Under DOE and Bureau contracts, a new design for a full-time, four-wheel -drive, articulated coal haulage vehicle emerged (1975-80) (42-43). Initially, this de- sign was referred to as the 411H diesel RAMCAR; the commercial version is now known as the 4114 diesel RAMCAR haulage vehicle. The first prototype vehicle was tested underground in a western Maryland coal mine on slopes up to 25 pet. Figure 66 shows the vehicle that was used during the underground trials. It is now com- mercially available from Jeffrey MMD. Mobile Bridge Conveyor Operator Compartment Prior to Bureau sponsorship, a commer- cially available continuous face haulage system designed for operation in very thin seams required protection for the mobile bridge carrier operator from roof 59 FIGURE 65.--Maximum-capacity shuttle car. FIGURE 66.--Diesel-powered face haulage vehicle. 60 falls and pinching hazards between the machine and coal rib. Jeffrey MMD and the Bureau filled this need by designing operator protection for this application (1976-85), which has since been commer- cialized by Jeffrey MMD (44). It has been installed on at least 15 vehicles sold to the mining industry, known as the model 5010 face haulage system. Figure 67 shows the protective operator compart- ment located on a mobile bridge carrier. Flexible Conveyor Train Under a cost-sharing arrangement with Joy Manufacturing Co. , the first version of a continuous flexible conveyor train (FCT) face haulage system (fig. 68) was FIGURE 67.-Mobile bridge conveyor operator compartment. FIGURE 68-Flexible conveyor train. 61 built and tested underground in a West Virginia coal mine; the first prototype was referred to as the model 1FCT-3BH (1976-80) (45). This is the only mobile belt conveyor system in the world capable of both vertical and horizontal bending radii. The first commercial version, 2FCT-1BH, was sold to a trona mine in Wyoming, and the systems are now being used worldwide. Recently, Joy has intro- duced another version (3FCT) for under- ground use as a continuous face haulage system. COAL MINE LOGISTICS TECHNOLOGY Although coal is extracted at the solid face within a mine, it is not available for consumption until it leaves the mine portal and is cleaned and blended. With- out coal transport and other mine logis- tical support such as service and main- tenance machines, materials handling devices, and transport of workers and supplies, no coal would leave the mine. The U.S. mines that have set new extrac- tion (production) records of coal mined per shift or day prepared their mines beforehand by having all logistical sup- port services in good working order. The mine logistical cost component has been calculated to be from one-third to one- half of the total capital cost required to open a new mine (46-47) , and these functions are critical to an adequate re- turn on capital investment. Also, many of the nonfatal mining accidents occur in this sector. For these reasons, the Bureau has conducted long-term research to develop improved methodologies that will optimize mine logistical functions and make them safer. The following is a summary of the major projects conducted in this area. CONVEYOR BELT SERVICE MACHINE Objective To significantly improve the efficiency and safety required to advance or retract a section belt to keep pace with the ad- vancing or retreating coal face. Justification It generally takes up to a full section crew (typically eight persons) and up to a full shift (8 h) to either advance or retract a section belt conveyor in order to keep pace with an advancing or re- treating coal face. A 100-ft belt move can require handling up to 4,000 lb of material, which may result in back injur- ies to workers. One way to reduce the time and labor along with improving safe- ty would be to mechanize the operation. This proposed solution has resulted in the design and fabrication of a mobile, battery-powered vehicle called the con- veyor belt service machine (CBSM). Description The CBSM (fig. 69) is a self-contained battery-powered vehicle capable of han- dling, storing, and transporting conveyor belting, wire rope, and associated struc- tures for sectional conveyor belts. It was conceived by the Bureau and designed and fabricated by Tracor MBA (formerly MB Associates) under Bureau contract J0333926 (JJ3-19, 48). The base structure of the CBSM was chosen to be similar to that of a shuttle car, with a length of 22 ft 6-1/2 in, a width of 10 ft 1 in, and a ground clear- ance of 8 in. A drawbar pull of 16,000 lb was selected for the CBSM based on an estimated weight of 32,000 lb for the fully loaded machine, assuming a 50 pet gradeability factor. The machine (fig. 70) can tram in either direction from creep up to 5 mi/h. It is capable of a 120-ft belt move distance and of operat- ing in a minimum seam height of 48 in. Table 14 gives a complete list of machine specifications. The machine belt winder accommodates belts up to 1/2 in thick by 42 in wide and provides adequate belt storage capacity for safe and convenient 62 Batteries Double- lapped belt winder Control box Slat conveyor Wire rope winder Operator compartment Resistor box Auxiliary hydraulic control Air reservoir Section belt tailpiece FIGURE 69.-Conveyor belt service machine. FIGURE 70. -Conveyor belt service machine with operator in tramming mode. transportation. It has been estimated from surface time study trials that the time required to connect a belt to the belt winder reel and to reel the belt onto the reel is 3 min 45 s. Figure 71 shows the CBSM on the left, attached to the belt piece, and the worktable located on the right side. Status In prior short-term underground test- ing, the CBSM was utilized for belt moves in three mines in West Virginia and Ken- tucky. Results indicated that modifica- tions were needed to improve tramming, brakes, and the belt winder lock. These 63 TABLE 14. - Conveyor belt service machine (CBSM) specifications MAIN FEATURES Mobile, battery-powered vehicle... To assist belt-move crew in making belt extensions or retractions. Belt structure storage area On-board CBSM. Storage reels Dual wire rope. Double-lapped belt winder For belting up to 1/2 in thick, by 20 to 42 in wide. Air compressor To power pneumatic tools. Minimum seam working height 4 ft. Machine envelope: Length 22 ft 6-1/2 in. Width 10 ft 1 in. Maximum drawbar pull capability... 16,000 lb. Battery power 128 V dc per 680 A*h. Total vehicle weight (empty) 28,000 lb. (estimated) . OTHER FEATURES AND COMPONENTS Wheelbase 8 ft 8 in. Battery end overhang 6 ft 1 in. Hitch end overhang 7 ft 9-1/2 in. Tire size 10.0 by 15. Inside turning radius 9-1/2 ft. Outside turning radius 22-3/4 ft. Traction drive (2) 30 hp at 1,200 r/min, 128 V dc, series-wound. Traction drive gear box 1-speed, 1.668:1 ratio. Braking Built-in park and service brakes. Wheel drive 4 required. Steering capability ±22.5°. Load carrying capacity 10,000 lb each wheel. Overall gear reduction 28.98:1. Traction drive controller SCR, 1 kA, 2 motors with braking. Ground speed at 2,000 r/min 4.14 mi/h SCR drives. Steering system 4-wheel, full power, hydraulic, closed center, nonload reaction type. Drive motor 20 hp at 1,800 r/min, 128 V dc, compound-wound. Hydraulic pump 20 gal/min at 1,500 lbf/in 2 , pressure-compensated, variable-displacement piston pump. Hydraulic reservoir 17 gal. Filter 10 ym, throwaway. Pneumatic drive Hydraulic motor. Compressor 5 hp , 2-stage, 100 lbf/in 2 , 20 ft 3 /min. Air receiver 7.5 gal, 80 to 100 lbf/in 2 . Wire rope drive Hydraulic motor. Winch maximum tension 6,000 lb. Winch maximum speed 60 r/min. Winch type Planetary gear reduction. Belt winder drive Hydraulic motor. Winder gear reduction Enclosed spur gear. Winder maximum speed.. 50 r/min. Winder maximum tension 1,400 to 2,000 lb at 1,500 lbf/in 2 . Slat conveyor drive Hydraulic motor. Conveyor chain tension 6,000 lb at 1,500 lbf/in 2 . Conveyor maximum speed 20 r/min. Conveyor lift travel 6 in. Conveyor lift capacity 5,000 lb at 1,500 lbf/in 2 . Tail section hitch type Hydraulic cylinder. Hitch lift capacity 2,000 lb per side at 1,500 lbf/in 2 . Control height Individual 10 in. SCR Silicon control rectifier. 64 FIGURE 71. -Conveyor belt service machine with hitch mechanism attached to belt tailpiece. modifications were made and the machine was surface tested and proved mine wor- thy. Negotiations are under way to place the machine underground in West Virginia for long-term testing and evaluation. MATERIALS HANDLING DEVICES Objective To reduce mine and equipment mainte- nance materials handling injuries by eli- minating manual tasks through the use of mechanized materials handling devices. Justification Conventional methods used today for supplying working sections require a con- siderable amount of manual handling by mining personnel. Common supply items that must be handled include oil, grease, cutting bits, posts, crossbars, roof bolts, rock dust, stopping blocks, and rail. Hazards associated with the manual handling of supplies result in numerous accidents. Manual materials handling injuries rep- resent a critical and persistent problem in underground mining operations; annu- ally they are the most frequent cause of nonfatal lost-time injuries. Although materials handling accidents have not historically accounted for many fatali- ties in underground mines, they are re- sponsible for nearly one-third (26 to 32 pet) of all nonfatal accidents in coal, metal, or nonmetal deep mines in the United States (49). In 1983, injuries related to materials handling accounted for approximately 34 pet of all lost-time and 32 pet of non-lost-time injuries in underground coal operations. Table 15 represents an analysis of in-mine materi- als handling accidents. Table 16 lists a summary of analysis findings by the U.S. Mine Safety and Health Administration. In view of these statistics, the Bureau's goal is to reduce injuries from handling mine and equipment maintenance materials by mechanization of manual tasks wherever possible through the use of low-cost, easily fabricated materials handling devices (49-50). TABLE 15. - Analysis of in-mine materials handling accidents 1 65 Handling mode On-section manual handling of equipment, supplies, and materials during production shift Supply movement from surface to point of use Section move: moving equipment to new working section Equipment maintenance Mine maintenance and maintenance material handling.... Total pet of all in- uries 11. 2 49. 5 13. 16. 3 10, 100.0 Data derived from study performed by MB Associates under Bureau contract J0333926. TABLE 16. - Summary of major health and safety analysis findings, percent Reporting category Maintenance Reporting category Maintenance Mine Machine Mine Machine Part of body injured: Back 38.6 21.8 5.7 31.9 25.9 4.6 Source of injury — Con. 5.6 NS NS NS NAp 21.5 10.9 Total 66.1 62.4 9.0 Accident type: 34.1 18.4 10.8 21.6 16.8 12.3 67.6 41.4 Overexertion lifting. . . . Nature of injury: 47.6 14.9 17.6 8.9 40.5 Overexertion n.e.c 10.1 63.3 55.2 10.8 Source of injury: 53.0 9.0 NAp NAp 17.6 Total Timbers, posts, caps.... 89.0 79.0 NAp Not applicable. n.e.c. Not elsewhere classified. NS Not specified. Source: U.S. Mine Safety and Health Administration, Health and Safety Analysis Center. Description and Status The devices that have been designed, fabricated and are ready for in-mine tests are summarized below. Scoop-Mounted Boom Hoist A simple boom devise was developed that could be used to lift components weighing up to 3,000 lb and to lower them safely to the ground. This boom (fig. 72) mounts quickly onto the front end of a small scoop. The design features of this device include — lifting capacity is 3,000 lb, lift can be either manual or powered, and the device is designed to be in- stalled or removed in 5 min. Lift-Transport Mechanism A floor-type maintenance jack was de- signed and fabricated to lift machine components from the bottom, transport them over short distances, and maneuver them into position for installation. The design features of the lift-transport mechanism (fig. 73) include — it has a lift capacity of up to 1,000 lb, it uses standard, automotive-type floor jack, and it is mounted on balloon tires for ease of movement. 66 FIGURE 72. -Scoop-mounted boom hoist. FIGURE 73.-Lift-transport mechanism. 67 Machine-Mounted Swivel Crane A lightweight, removable, storable lift crane was developed that could be mounted on maintenance carts or on mining ma- chines. This crane (fig. 74) swivels for locating the load and lifts it by a man- ual crank. The design features of this device include — its load capacity is 500 lb, the boom height ranges from 24 to 68 in, depending on leg length, its arm ra- dius is 24 to 48 in, and it mounts and stows without tools. miners balances the beam on the swivel part of the jack; the other operates the jack handle to raise the beam to the roof or into final position. When not being utilized to handle timbers or beams, this vehicle serves as an ordinary flatcar for hauling mine supplies. The design will accommodate either rail-mounted or rubber-tired supply cars and different rail coupler designs, and can be fabri- cated in a typical mine shop. This de- vice is being tested underground in an Ohio coal mine. Container-Workstation Transporter A special container was designed in such a manner that many of the mainte- nance tasks performed in a mine section could have the required tools and sup- plies mounted in a transportable con- tainer. The container is moved around a working section by a transporter designed to be positioned around the container. A lift mechanism raises the container off the floor. The overall load is carried by the wheels as the operator controls motion by pulling, steering, and balanc- ing the unit on its axle (fig. 75). The design features of this device include — weight of 150 lb, 500-lb carrying capac- ity, balloon tires for ease of movement over rough bottom conditions, and manual guidance and locomotion. Timber Car The need for lifting and positioning heavy mine timbers is ever present in mining operations. The timber car was built to eliminate much of the manual lifting effort required for this process. The rail-mounted timber car (fig. 76) uses a hydraulic jack, recessed into the carrying platform of the flatcar, to lift and swivel into final position timbers and metal crossbeams to the roof for per- manent installation. These wooden or steel beams, which can weigh up to 300 lb each, are typically lifted and supported manually by two or more mine personnel, one on each end. With the use of the timber handling flatcar, one of the FIGURE 74.-Machine-mounted swivel crane. 68 FIGURE 75.-Container-workstation transporter. 69 FIGURE 76.-Timber car. 70 Diesel-Powered Forklift A diesel-powered forklift (fig. 77) de- signed specifically for underground duty uses palletized loads as much as possible to transport supplies. In-mine trials began in 1986. Some of its main features include — mine duty design with adequate ground clearance (7 to 11 in), Perkins 200 series diesel engine rated at 59 hp with dry-type safety system, forklift mast rated at 1,500 lb load carrying capacity, cable winch attachment with 3,000 lb pull capacity, skid steering, and overall weight of 7,600 lb. This vehicle was tested in an Illinois coal mine in 1986-87; underground testing in- dicated the usefulness of using a diesel- powered forklift to transfer pallet loads of mine supplies. TRACK MAINTENANCE VEHICLE Objective To develop a track maintenance vehicle to clean the track for visual inspection and to measure track gauge and cross - level deviation. Justification Most deep mining track systems require periodic inspection and maintenance. Track inspection is normally based upon visual observations of the track layout and the ride quality of mantrips assessed by operators and supervisors. However, accurate and reliable visual inspection of the track condition can only be accom- plished if the surface of the ties are FIGURE 77.-Diesel-powered forklift. 71 free of debris. Track cleaners presently employed by the mining industry utilize scraper blades that remove the bulk of debris; however, layers of dirt that lie atop the ties, fishplates, spikes, and rails are not removed. Furthermore, cur- rent machines cannot clean in and around track switches and frogs, critical compo- nents of a track system that require more frequent inspection and maintenance. In view of this need, the Bureau has de- signed and fabricated a prototype track maintenance vehicle capable of not only cleaning the track well enough for visual inspection but also checking the track gauge and cross-level. Description The track maintenance vehicle (fig. 78) is rail mounted, is pulled by a locomo- tive, and contains the following subsys- tems: carrier, brush assembly, material- removal system, track inspection system, electrical equipment and controls, and hydraulics. The carrier, which is a specially de- signed flatbed car, is 10 ft long and 5 ft wide. The underframe is mounted on two Huwood-Irwin axle wheel assemblies with a capacity of 3 st per axle. The carrier's basic structure consists of FIGURE 78.-Track maintenance vehicle. 72 four No. 6 longitudinal channels and two transverse end beams. The brush assembly, as shown in figure 79, is driven by two hydraulic motors. The frame and brush are lowered to the track until their own weight is balanced by an adjustable spring assembly. The material removal and dust control assembly (fig. 80) consists of a shroud to contain the materials coming off the brush and a conveyor that transports the material to either side of the track. The track measuring device consists of two main parts: the track inspector assembly and meter box. The track gauge and cross-level deviation measurements are based on a change of voltage; the device uses a potentiometer for cross- level deviation and a linear variable differential transformer for track gauge deviation. Status A brief underground test of the vehicle was conducted in a West Virginia coal mine, with the performance of each sub- system evaluated separately. Detail de- sign and fabrication plans will be made available to the mining industry upon completion of underground testing and evaluation, along with all data collected during testing (48). RETURNING COAL WASTE UNDERGROUND Objective To determine the feasibility, costs, and benefits of disposing of coal mine waste underground. Justification Mine waste or refuse is an unavoidable byproduct of deep-mine coal production. Although the amount of refuse that must be disposed of varies from one mining operation to another, many deep mines must dispose of one-third of the raw product mined. One potential solution for the disposal of mine refuse is to re- turn it underground and fill up some of the mined-out areas. This approach re- duces the amount of refuse stored on the surface in piles or in ponds, provides for some subsidence protection, and al- lows additional coal to be rained in pil- lars that would ordinarily be sterilized by providing additional support. Hydraulic motor Shroud Brush FIGURE 79. -Track maintenance vehicle brush assembly. Rail track 3' Rail gauge Track width / Brush FIGURE 80. -Track maintenance vehicle material removal system. Description The Bureau sponsored an approach that would return mine refuse to the mine via a water slurry pipeline. A hydraulic transportation system was designed with centrifugal slurry pumps that transport at least 45 pet solids by weight, crushed so the largest pieces are between 1 and 2 in (51 ). Slurry transport equipment has been set up near the portal of a room- and-pillar mine in Appalachia. The es- sential portion of the concept is to build filter barriers in the entries of the section to be filled using a construction method shown in figure 81. By filling behind these filters with a coarse particle-size gradient, the fines are trapped, allowing the water to be collected in a sump and pumped away for control and reuse. The proposed 73 backfilling sequence at the mine is depicted by figures 82, 83, and 84. A schematic of the slurry transport equip- ment located near the mine portal is shown in figure 85. Status Because of funding limitations, the testing was limited to the backfilling of three crosscuts in a nearby abandoned portion of the mine with the expectation that a cooperative agreement could be made with the mine to obtain long-term collection of data. The refuse-water mixture was pumped about 2,000 ft to the backfilling area. The crosscuts filled were 3 ft high by 20 ft wide by 50 ft long, each with a capacity of 120 st. Final results will be available after the conclusion of in-mine data gathering. SURFACE-TESTING PROTOTYPE MINE EQUIPMENT As described above, detailed studies complemented with input from industry and academia have resulted in a comprehen- sive, long-term research effort that ad- dresses the equipment technology needs of the mining industry. As part of the overall effort, new prototype machines were designed to fill critical areas in order to improve productivity and health and safety in the underground coal mining environment. Because of the high cost of underground prototype equipment testing, modification, and evaluation, it became apparent that extensive surface testing and evaluation were necessary prior to any in-mine trials. To meet this need, surface test facili- ties were designed and built at Bruceton, PA, to facilitate a thorough evaluation and debugging of prototype mining equip- ment prior to underground deployment in a production mode. This Bureau facility assists in determining the effectiveness and reliability of prototype coal min- ing equipment. Artificial coal blocks — a mixture of coal, fly ash, and cement — can be cast into underground configura- tions for cutting trials. Coal conveying equipment is evaluated using run-of-mine coal, crushed limestone, or other bulk materials. Maneuverability of mobile raining equipment is tested in a simulated room-and-pillar raockup area. All other machine functions are proven or disproven using specialized procedures and instru- mentation tailored to the specific piece of equipment under test. The unique capabilities of this Bureau facility make it a valuable asset to mining research. Without this facility, many of the proto- types described within this report could not have advanced to the underground evaluation stage. Figure 86 shows some of the main compo- nents (test buildings) of the Bureau's surface test facilities. Figures 87 and 88 are views inside the facilities used largely to simulate and test new ideas and designs for mobile mining equipment and associated components. 74 i Floor Wooden posts Roof bolts Inby .Wire mesh and filter fabric - Outby inby 6-in diam wooden post Clay SIDE VIEW * FIGURE 81. -Typical fitter barricade for returning coal waste underground. 75 ■^P Stopping Backfilled refuse FIGURE 82.-Returning coal waste underground, backfilling sequence-phase 1. FIGURE 83.-Returning coal waste underground, backfilling sequence-phase 2. 76 FIGURE 84. -Returning coal waste underground, backfilling sequence-phase 3. X Coarse refuse drain and rinse screen Minusl/4 in plus5mesh 56st/h 4gal/min I Dryer ..MX Minusl/*: plus 28 mesh 36st/h 6gal/min Fine refuse screen Minus 28plus 100 mesh 6st/h 3 gal/min Existing refuse belt To vacuum filter Minus 5 plus lOOmesh 98st/h 13 gal/min Thickener Minus 100 mesh 25st/h I59gal/min Make-up water Proposed conveyor