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42 www.coalage.com December 2018 operating ideas continued air tank can be recharged by portable tanks, cylinders, or compressed air lines when the on-board supply becomes depleted. The engine control panel contains all necessary gauges, override, and stop switch- es as well as an emergency intake shutdown actuator and a manual fire suppression ac- tuator. The portable fuel tank holds six gal- lons and operates the rescue support vehicle for four hours. When mine rescuers need to refuel the machine, these fuel tanks can be changed out using dry quick connect fittings, making it possible for a rescue team exiting their shift to take the fuel tank out to be re- filled, and for the incoming team to bring a full tank in for use during their shift. The die- sel engine drives a variable displacement hy- draulic pump that powers the machine func- tions. Hydraulic valves control the right and left track motors forward, reverse, and high/ low speed functions, the bucket lift and tilt up and down, and the grapple open and close functions. A hydraulic power takeoff (PTO) is also available to power a winch, drill, saw or a variety of needed hydraulic tool implements. When the operator is in visual range (i.e., has line-of-sight), the machine can be operated by radio remote control, which uses joysticks and switches to command the machine functions. For extended rang- es, the operator can control the machine by way of a remote tablet interface, which includes machine function control and video. The machine is equipped with LED lighting and four video cameras to docu- ment conditions as it moves throughout the mine. The video cameras are housed in a dual enclosure, which includes an emitter used to permit video visibility in low-light conditions. Based on input from mine rescue teams, the trailer design includes these features: • A deck height of 22 inches so that fi- ber-optic cable reels for the mine res- cue communications system can be carried and kept within the desired height envelope of the trailer. • An arm for unspooling the fiber op- tic cable. • Tire balls in the trailer tires to pre- vent flats. • Removable sideboards that convert the trailer to a flatbed, with the side- boards also functioning as stretchers. • A tailgate designed to be laid down, ex- tending the deck length to eight feet. • Hydraulic lines from the front to the rear of the trailer so that PTO acces- sories can be operated without dis- connecting the trailer. • An aluminum body to keep the weight down, but with a load capacity of 1,000 pounds. Machine Status Based on the above final specifications and extensive industry feedback and re- quests, the mine rescue support vehicle is currently being modified by ROHMAC and will include the following upgrades: • Due to concerns raised about the lim- ited on-board air supply and restart ability, a hydraulic start and safety con- trol circuit will replace the air systems, thus allowing the hydraulic pump to recharge the system on board. • Changes to the exhaust treatment system are under way to improve op- erating efficiency, enhance gradabili- ty, and extend operating times before required service. • Components are being relocated to save space and improve serviceability. • Technology is being added to trans- mit video data from the machine in a format that can be sent to a com- mand center. ROHMAC is currently working through the application process for MSHA-permis- sible approval of the machine. With the machine having been designed and built to meet the requirements of other permis- sible machinery used in underground coal mines, NIOSH anticipates that the vehicle will be available for use in the future. Disclaimer The findings and conclusions in this paper are those of the authors and do not necessar- ily represent the official position of the Na- tional Institute for Occupational Safety and Health, Centers for Disease Control and Pre- vention. Mention of any company or product does not constitute endorsement by NIOSH. Larry D. Patts is a research physical sci- entist with NIOSH. Jeremy Rohrbaugh is a sales engineer with ROHMAC. Joseph Schall is a health communications spe- cialist with NIOSH. For more information, contact mining@cdc.gov.