In an apparatus for applying rock dust with foam to a mine wall to suppress mine fires and prevent explosions, foam and air-entrained rock dust are separately conveyed to a combination nozzle and mixing device. The air-entrained rock dust moves axially through a passage into an enlarged chamber while foam moves through an array of openings surrounding the passage that direct the foam in a helical path. The helical movement of the foam, and the reduction of the velocity of the air-entrained rock dust resulting from its movement into the enlarged chamber, enhance mixing. The mixture passes from the enlarged chamber through a restricted nozzle to increase the velocity of the mixture for effective spraying. The restricted nozzle has an array of internal flow-interrupting baffles that further promote mixing by generating turbulence, condense the stream, and shape the spray pattern.

A mine safety system is provided for preventing coal dust explosions in an underground coal mine. The system comprises a reservoir, for storing an inerting agent; a compressor, for providing compressed air; and a mixer, coupled to the reservoir and the compressor, for mixing the inerting agent and compressed air and providing the mixture to the underground coal mine. The reservoir is located outside of the coal mine.

A mine safety system is provided for preventing coal dust explosions in an underground coal mine. The system comprises a reservoir, for storing an inerting agent; a compressor, for providing compressed air; and a mixer, coupled to the reservoir and the compressor, for mixing the inerting agent and compressed air and providing the mixture to the underground coal mine. The reservoir is located outside of the coal mine.

An apparatus for dispersing liquid flame retardant mixtures mounts in the bucket of mine scoop. The apparatus has a housing which is generally sized to fit within a mine scoop bucket while leaving space in the bucket for moving mine material. The housing has a reservoir within it for holding a fire prevention mixture. The mixture is a liquid mixture and the apparatus has a motor, pump, tubes, and nozzles for dispersing the fire prevention mixture. The apparatus accommodates a hydraulic cylinder for moving the mixture dispersing apparatus back and forth within the scoop bucket. The hydraulic cylinder is operated to position the nozzles for dispersing the liquid. Some embodiments of the apparatus have a front face with scraper blade elements that operate as a scraper blade similar to scraper blades in scoop buckets that do not have the apparatus in place.

An apparatus for dispersing liquid flame retardant mixtures mounts in the bucket of mine scoop. The apparatus has a housing which is generally sized to fit within a mine scoop bucket while leaving space in the bucket for moving mine material. The housing has a reservoir within it for holding a fire prevention mixture. The mixture is a liquid mixture and the apparatus has a motor, pump, tubes, and nozzles for dispersing the fire prevention mixture. The apparatus accommodates a hydraulic cylinder for moving the mixture dispersing apparatus back and forth within the scoop bucket. The hydraulic cylinder is operated to position the nozzles for dispersing the liquid. Some embodiments of the apparatus have a front face with scraper blade elements that operate as a scraper blade similar to scraper blades in scoop buckets that do not have the apparatus in place.

An apparatus for dispersing liquid flame retardant mixtures mounts in the bucket of mine scoop. The apparatus has a housing which is generally sized to fit within a mine scoop bucket while leaving space in the bucket for moving mine material. The housing has a reservoir within it for holding a fire prevention mixture. The mixture is a liquid mixture and the apparatus has a motor, pump, tubes, and nozzles for dispersing the fire prevention mixture. The apparatus accommodates a hydraulic cylinder for moving the mixture dispersing apparatus back and forth within the scoop bucket. Some embodiments of the apparatus have a front face with scraper blade elements that operate as a scraper blade similar to scraper blades in scoop buckets that do not have the apparatus in place.

An apparatus for dispersing liquid flame retardant mixtures mounts in the bucket of mine scoop. The apparatus has a housing which is generally sized to fit within a mine scoop bucket while leaving space in the bucket for moving mine material. The housing has a reservoir within it for holding a fire prevention mixture. The mixture is a liquid mixture and the apparatus has a motor, pump, tubes, and nozzles for dispersing the fire prevention mixture. The apparatus accommodates a hydraulic cylinder for moving the mixture dispersing apparatus back and forth within the scoop bucket. Some embodiments of the apparatus have a front face with scraper blade elements that operate as a scraper blade similar to scraper blades in scoop buckets that do not have the apparatus in place.

A mine safety system is provided for preventing coal dust explosions in an underground coal mine. The system comprises a reservoir, for storing an inerting agent; a compressor, for providing compressed air; and a mixer, coupled to the reservoir and the compressor, for mixing the inerting agent and compressed air and providing the mixture to the underground coal mine. The reservoir is located outside of the coal mine.

A mine safety system is provided for preventing coal dust explosions in an underground coal mine. The system comprises a reservoir, for storing an inerting agent; a compressor, for providing compressed air; and a mixer, coupled to the reservoir and the compressor, for mixing the inerting agent and compressed air and providing the mixture to the underground coal mine. The reservoir is located outside of the coal mine.

Rock dust is applied to a mine wall for mine fire suppression in combination with a chemical foam, by generating the foam from air and a foamable liquid in a mixing chamber, and delivering the foam through one flexible conduit and air-entrained rock dust through another flexible conduit to a portable assembly composed of a Y-joint and a delivery nozzle for combining the foam and rock dust and applying the combination directly to a mine wall.