• -ay ^ * c i o » o,^ *^ •'* a" ^ ^•^ » :^'. -^ '"' v^^ .0^ K^*^"^ o • • , — - • • - - '>>^ . ♦ • . •'v . \^ , . ^ 'ir .«•■"'- ^ i?v^ ♦ fCCVSK A" ^n ey ♦ ' " '^, .iV • -^.^^^ .«' '"' % -&^ oil-- . ^-^ '°-** <0^ ^^ '•"•♦ ^^-n*.. ^K" ^^^\.^j^,.\^ /'&"•'% ^^^^'X ^-^^ -•^*"' "^ V . » • "-0 V^' ^^-n.. ^^ • • » o jy v\ 'J -e^" ... ^-^ "•* av" "C* ^^" J> % 'o^T* .^ ^^ ■ ^^ . i> ■<^ ^^ ■cr. ♦'TC * A. ^ IC 8954 Bureau of Mines Information Circular/1983 Automatic Fire Protection for Mobile Underground Mining Equipment By Guy A. Johnson UNITED STATES DEPARTMENT OF THE INTERIOR Information Circular 8954 n Automatic Fire Protection for Mobile Underground Mining Equipment By Guy A. Johnson UNITED STATES DEPARTMENT OF THE INTERIOR James G. Watt, Secretary BUREAU OF MINES Robert C. Norton, Director Library of Congress Cataloging in Publication Data: Johnson, Guy A Automatic fire protection for mobile uiulcTgroimd mining equipment. (Bureau of Mines information circular ; 8'>S4) Ini. ludcs bibliograpliical references. Supt. of Docs, no.: I 28.27!89'S4. 1. Mining machinery — !■ ires and tire pre\ention. I. litle. II. Se- ries: Information circular (United States. Bureau of Mines) . 8954. -T^^N^gS.III I-TNSISI 622s[H22\8| 83 600271 CONTENTS Page Abstract 1 Introduction 1 Design concept 2 In-mine fire test 6 Alternative system designs. 6 Availability 12 Conclusions 12 ILLUSTRATIONS 1 . Typical components of an automatic system 2 2 . System schematic 3 3. First-generation design concept 4 4 . Laboratory testing a thermal fire sensor 5 5 . Fire testing on load-haul-dump engine mockup 5 6. Installing first-generation system on underground load-haul-dump at Lake- s hor e Mine 6 7. System control box on underground vehicle 6 8. Fire pan above the engine area on test vehicle 7 9. Filling fire pans prior to on-vehicle fire test 7 10. Lighting the underground test fire with a propane torch 8 11. Flame from the test fire in the engine area 8 12. Automatically extinguishing the test fire 9 13. After the test fire is extinguished 9 14. Alternative system for small load-haul-dump 10 15. Alternative system for large load-haul-dump 10 16. Alternative system for underground haulage truck 10 17. Alternative system for underground lubrication truck 10 TABLE 1. In-mine, proof -of -concept testing of automatic fire protection systems for underground vehicles 11 AUTOMATIC FIRE PROTECTION FOR MOBILE UNDERGROUND MINING EQUIPMENT By Guy A. Johnson ABSTRACT To improve productivity and cut costs, modern underground mining oper- ations have become more mechanized. This mechanization has increased the usage of fuels, hydraulics, and electrical equipment associated with diesel-powered vehicles, thereby also increasing the hazards of under- ground mine fires. The Bureau of Mines evaluated the fire hazard prob- lem and assembled prototype components for a system that would auto- matically sense and extinguish fires on mobile underground equipment. The prototype system and alternative designs were in-mine-tested and proved effective. This report summarizes this technology, which can cost effectively help solve the problem of fire hazards on underground vehicles. INTRODUCTION As part of its fire and explosion program, to help ensure safer work- ing conditions for miners, the Bureau of Mines has spent several years studying improved fire protection for mobile equipment used in surface mining. With the basic R&D completed, the Bureau is now working with the Mine Safety and Health Administration (MSliA) , the National Fire Pro- tection Association (NFPA) , and fire equipment manufacturers to refine this technology. Building upon this effort, the Bureau has also com- pleted a project to improve fire protection for mobile equipment used in underground mining. This work was undertaken because the danger of underground fires has recently increased as a result of increased usage of fuels, hydraulics, and electrical equipment associated with diesel- powered vehicles. Specific initiative came in 1976 when the mining in- dustry had two fatalities because of a fire on a load-haul-dump (L-H-D) at Hecla's Lakeshore copper mine near Casa Grande, AZ. The Bureau had already investigated the basic technology for rugged fire protection for large surface mining machines like haulage trucks, front-end loaders, draglines, shovels, etc.; this technology, though, needed to be modified so it could be applied to the diesel-powered underground mobile raining equipment. a 'Supervisory mining engineer. Twin Cities Research Center, Bureau of Mines, Minne- apolis, MN. DESIGN CONCEPT Manually activated fire protection sys- tems that use fixed piping and dry chemi- cals have been used on underground vehi- cles for a number of years and have had some success. The manual systems are reliable but require someone to activate them. Some vehicle operators may panic during a fire emergency and fail to actu- ate the system. Therefore, for greater reliability, automation is needed. Using the manually activated systems as a starting point, the Bureau added sensors and automatic controls so that a fire would be sensed by on-board thermal sensors and suppressed automatically (i.e., when it was still small and controllable) . The automatic fire protection systems utilize a multipurpose, dry chemical fire-suppressing agent. This fire extin- guishant is effective on fires involving combustibles on a vehicle and is commonly used underground; thus, mine personnel are comfortable with it. Typical compon- ents of an automatic system are shown on figure 1. The system shown would auto- matically shut down the engine and set the brakes in the event of a fire. Since no one system could solve every type of fire hazard, the design concept (figs. 2-3) was developed to be very ver- satile, so that mines would have the flexibility to fabricate a system commen- surate with their needs. During the com- ponent selection phase of this R&D, tests were run in the laboratory to investigate the timing required by various thermal sensors to sense a typical vehicle fire (fig. 4). A mockup of the engine com- partment of a typical L-H-D was then built and tests were run to determine the amount of dry chemical agent needed to extinguish a typical fire (fig, 5). The prototype hardware performed well; thus, the next step was actual on-vehicle test- ing underground. -Dashboard manual actuator Electrical actuator Control panel Remote manual actuator Spot-type thermal sensor Linear thermal sensor Nozzle Agent tanks- FIGURE 1. - Typical components of an automatic system. r o — E U- o c o o o> c c i|! O t/> W) or I *=• .2 o tn ^ — o c I— o /x — o ^_ CO T3 O I -r\. r £ I'D 0) O i- O V. ^ o o a; «/) c c — ; a C UJ o ^ 1/1 LU ID O QJ O > E o ■- •- n is *~ >« J _L _i Q. (U U c o u c CT U) (U -a c o (O c 0) C3> LL LU Qi Z) O o O CD FIGURE 4. - Laboratory testing a thermal fire sensor. FIGURE 5. " Fire testing on load-haul-dump engine mockup. IN-MINE FIRE TEST In 1911 y the Bureau installed the first-generation prototype system on an L-H-D (fig. 6) at the Lakeshore Mine, then operated by Hecla Mining Co. near Casa Grande, AZ. control unit (SCU) warn the driver of matically set off driver abandoned the This system had a (fig. 7) that would a fire (and auto- the system if the vehicle) , thermal sensors in the vehicle's engine, articu- lation, and transmission areas, and pip- ing to distribute the dry chemical fire suppressant. After 1 year of successful on-vehicle testing (i.e., no accidental actuations), pans were installed on the vehicle and filled with heated hydraulic oil prior to an actual in-mine, on-vehicle fire test (figs. 8-9). Figure 10 shows the light- ing of the fire in the vehicle's engine area. The system sensed the test fire (fig. 11), sounded the alarm, and auto- matically extinguished the fire (figs. 12-13). This in-mine fire testing was conducted in close cooperation with both mine and MSHA personnel. ALTERNATIVE SYSTEM DESIGNS In 1979, 1980, and 1981, numerous design alternatives were studied and in- mine-tested to demonstrate to the in- dustry the flexibility and reliability of this technology. These systems were evaluated on different sizes of L-H-D' s, an underground truck, and a lubrication truck (figs. 14-17.) FIGURE6. - Instal ling first-generation system on underground load-haul-dump at Lakeshore Mine. Typical components of the system are shown in figure 1 . FIGURE 7. - System control box on underground vehicle. Location of control panel is shown in figure 1. FIGURE 8. - Fire pan above the engine area on test vehicle. FIGURE 9. - Filling fire pans prior to on-vehicle fire test. FIGURE 10. - Lighting the underground test fire with a propane torch (outlined), FIGURE 11. - Flame from the test fire (outlined) in the engine area. (Approximately 1 min after lighting.) ^HP"-- 'W^ FIGURE 12. - Automatically extinguishing the test fire. (Approximately 2 min after lighting,) FIGURE 13. - After the test fire is extinguished. (Approximately 4 min after lighting.) 10 Check valves (2) Detection cable Control console Dashboard actuator Check valves (2) 30-lb dry chemical tank Electric actuation device ' Nozzles Air cylinder (fuel shutoff ) FIGURE 14. - Alternative system for small load=haul-ciump. 30-lb dry chemical tank - Dashboard actuator Control consote Detection cable (ttiermal) Nozzles (2) Electric actuatkxi device Air cy(nder (fuel shutoff) FIGURE 15. - Alternative system for large load-haul-dump. - Air cylinder (fuel shutoff) - Control valve (set brakes) • Nozzles ■ Detection cable (ttiennal) Control console 1 2 vdc ■ Dashboard actuator Check valves 30-lb dry chemical tank Electric actuation tank FIGURE 16. - Alternative system for underground haulage truck. Horn-lamp SCU LT-LP-101-20 ctwmical tank Squib actuator Detector kx)p -Nozzles Hand-portable fire extinguist)er FIGURE 17. - Alternative system for underground lubrication truck. 11 Table 1 summarizes this follow-on work, which tested system designs on seven types of vehicles in four underground mines. The individual tests lasted from 10 to 34 months and total 158 months of debugging, redesign, and final proof -of - concept testing of prototype hardware. TABLE 1. - In-mine, proof -of -concept testing of automatic fire protection systems for underground vehicles Mine Vehicle-'- Dates Comments Hecla Mining Co., Lake- shore (copper) Mine, Casa Grande, AZ. Do, Bunker Hill Mining Co., Bunker Hill (lead-zinc) Mine, Wallace, ID. Do. Do. Morton Salt Co. , Grand Saline (salt) Mine, Grand Saline, TX. Union Carbide Corp. , Pine Creek (tungsten) Mine, Bishop, CA, Wagner ST-2B L-H-D. iQO» •••••••• Eimco L-H-D. In-house modi- fied TO- 2 hauler. Plymouth DMD- 24 diesel locomotive. Caterpillar 450-f ront-end loader. Getman lube truck. May 1976- July 1978 May 1977- July 1978 Mar. 1978- Nov. 1980 Aug. 1979- Nov. 1980 Mar. 1978- Nov. 1980 Apr. 1978- Nov. 1980 Apr. 1980- Feb. 1981 The 26 months of testing showed that the basic system design was good, but an improved ac- tuation device was needed. Tests on a 2d vehicle with pro- totype hardware with an im- proved actuation device proved successful. Testing termin- ated with closure of the mine. The hardware was retrofitted in August 1979 with the Squib electric actuation device, which proved to be the best actuation device tested. This system also had the Squib electronic actuation device retrofitted in August 1979. A preproduction Squib electron- ic actuation device system was successfully tested for 14 months. The Squib electric actuation device was retrofitted to this 2d-generation prototype in September 1979. Another preproduction model of the automatic fire protection system for underground vehi- cles was successfully tested. ^Reference to specific equipment or manufacturers does not imply endorsement by the Bureau of Mines. NOTE. — 6 systems were tested on 7 vehicles in 4 underground mines. The tests ranged from 10 to 34 months in length. A total of 158 months of in-mine work helped to develop and debug prototype hardware. Some problems occurred with false actua- tions (most of which were traced to "horseplay" by miners trying to see how much heat the system could sense before going off), but the final system proved rugged enough for long-term, in-mine use at a reasonable cost. 12 AVAILABILITY As a result of this work, automatic fire protection systems are currently available from several manufacturers. These systems cost between $2,000 and $4,000 installed. 2 The NFPA of Quincy, MA, which has written the Life Safety Code and the National Electric Code, is currently planning to write consensus in- dustry standards to address the problems of fire protection in underground mines, utilizing the Bureau's in-mine-proven research results. More detailed information from two technical reports is available on the Bu- reau's research and testing of this technology .3 CONCLUSIONS In cooperation with many mining compan- ies and fire protection equipment manu- facturers, the Bureau has investigated and in-mine-tested automatic fire protec- tion systems that have proven effective for underground vehicles. The choice of what system to use depends on vehicle use patterns and duty cycles, maintenance requirements, vehicle dimensions, and the locations of the vehicle's fire hazard (usually the engine compartment) and the operator's station. As a result of this Bureau work, vari- ous levels of sophistication in automatic systems are now commercially available. These range from basic detection and dry chemical suppression systems to sys- tems with redundant sensing, visual and •^The Bureau purposely worked with more than one component manufacturer, to keep commercial competition high and pricing low. audible operator alarms , delayed dis- charge, machine power shutdown, circuit fault warning, and self-contained backup power supply, all with manual discharge capability. An analysis of the specific fire protection requirements for a given application will aid in selection from among this list of system options. -^McDonald, L. A. , and G. R. Reid. Au- tomatic Fire Protection System for Mo- bile Underground Metal Mining Equip- ment (contract HO252038, Ansul Co.). Vol. II. Long Term Validation Testing. BuMines OFR 159-82, 1981, 242 pp.; NTIS PB 83-1 14876. Reid, G. R. , D. L. Stockwell, and R. J. Plog. Development of an Automatic Fire Protection System for Mobile Under- ground Metal Mining Equipment, Phase II Report (contract HO252038, Ansul Co.). BuMines OFR 81-76, 1975, 151 pp.; NTIS PB 254 851. INT. BU.OF MINES,PGH.,P A. 27160 9631 •^u..^ ^^rfi .^' >^ CV <^' <. — ••/ \«y* -^^.^y \:«y^^^ '.«£» * i?' ♦S jA o « • ♦ '^ •^^^^^ 4^^ .. fe'.. u .^^ ^^'^%iA^ \/ /^\ \,^^ y^^. \/ :- '-n.o^ 0^, h ^^ '%' • -•« "^o <^^ "^.. V ^''^^.. • ^^ V..^'^ *