NIOSH Mining Safety and Health Research

In the area of fire prevention, the flammability and fire resistance of several materials to reduce their potential fire hazards were evaluated, including noise abatement materials used to line the cabs of large, mobile mining equipment. The results of this study are used by MSHA and the mining community as guidelines for the selection of such materials. A safety awareness toolbox, "Tame the Flame" has been developed to reduce the number of flame cutting and welding fires. The effectiveness of fire suppression systems in preventing and extinguishing fires in cabs of large, mobile mining equipment was investigated. A major fire equipment manufacturer is actively pursuing the development of cab fire prevention and suppression systems based upon this research..

Fire detection is a critical component in the safety of underground mines. NIOSH developed and successfully tested and demonstrated a smart fire sensor system in a coal mine that utilizes several types of fire sensors and a neural network analysis to determine the source of the fire signature and eliminate false alarms. An in-mine field demonstration of the reliability and effectiveness of off the shelf smoke detectors for fire detection in underground metal and nonmetal mines was completed. Laboratory tests of both a prototype detector and a commercially available smoke detector have indicated good sensitivity to the smoke from many different types of fires.

Computational fluid dynamics (CFD) simulations were conducted to investigate the spontaneous heating of coal in longwall gob areas under various ventilation schemes. These simulations confirmed the existence of the critical velocity zone behind the shields in the gob, and showed the existence of other critical velocity zones in both an active panel and a mined out panel. The results are being used to develop optimum ventilation schemes for mines with methane and to characterize gob gas flow to reduce the risk of spontaneous combustion.

Full-scale, remotely installed cementitious and rigid foam mine seals were tested in the Lake Lynn mine. Results show that remote seal construction has potential, but that it is not always successful in cutting off oxygen to a fire. Full-scale, in-mine experiments conducted at the NIOSH Lake Lynn Experimental Mine to determine the flow characteristics, stability and fire-suppression capability of gas-enhanced foam demonstrated that the gas-enhanced foam could be used to aid in the extinguishment or suppression of a mine fire.

A series of large-scale experiments to evaluate water sprinkler, deluge, and dry chemical belt suppression systems under high ventilation airflows (500 and 1400 ft/min) were completed. The results are being used to establish guidelines for installation of suppression systems on belts.