Fig. 15. Locomotives with self-rescuers in individual wood and glass cases on 16. Track workers with self-rescuers on their belts, Creighton coal works_ 19. Rack in check room holding miners' belts with self-rescuers attached 20. Floor plan of check house for self-rescuers and electric cap lamps, Barr mine____ 21. Rack for holding detached self-rescuers and electric cap lamps; design from Clearfield Bituminous Coal Corporation____. 22. Miners wearing self-rescuers at work in Clymer No. 1 mine----- USE OF THE MINERS' SELF-RESCUER By S. H. KATZ and J. J. FORBES WHAT THE SELF-RESCUER IS Self-rescuers are pocket-size respirators that protect the wearer from air contaminated with that poisonous gas, carbon monoxide. The purpose of the self-rescuer is to provide a miner with protection from carbon monoxide for at least half an hour and thus help him to escape from a mine in which a fire is burning or an explosion has occurred. A self-rescuer can be used also by workers aboveground who may through accident become surrounded by atmospheres containing carbon monoxide. 1 Two hazards threaten the miner who escapes serious injury by fire or violence in a large mine fire or explosion-he may be poisoned by carbon monoxide or he may be suffocated by breathing an atmosphere that does not contain enough oxygen to support life. In order to save himself, the miner must either erect a barricade against afterdamp and wait until ventilation is restored, as described in Miners' Circular 251 of the Bureau of Mines, or take a long chance in getting out of a mine through entries free of afterdamp. Although the self-rescuer does not supply oxygen, it does remove the hazard of carbon monoxide for half an hour or more and thus greatly increases a miner's chance of getting out alive. Thus the self-rescuer is a life-saver for the miner, and self-rescuers are as essential in mines as life preservers on ships. This paper tells about the construction and use of self-rescuers; it also describes four underground safety systems for distributing them. These systems are in effect at mines of the following companies: Penelec Coal Corporation of the Penelec Power Co., Indiana County, Pa.; Creighton coal works of the Pittsburgh Plate Glass Co., Creighton, Pa.; and Clearfield Bituminous Coal Corporation, Indiana, Pa. The writers are indebted to these companies for permission to photograph and describe their equipment and methods and for the assistance given by them in the preparation of this paper. 1 Paul, J. W., Pickard, B. O., and von Bernewitz, M. W., Erection of Barricades During Fires or After Explosions: Miners' Circ. 25, Bureau of Mines, 1923, 36 pp. HOW THE SELF-RESCUER IS MADE Until the self-rescuer is used, it is inclosed in a brass case sealed air-tight with soft solder and having a cover that may be ripped off by hand. The case measures 7 by 35% by 118 inches outside; it weighs 21 ounces when it contains the self-rescuer. The weight of the self-rescuer alone is about 13 ounces. A miner may carry a selfrescuer in his coat pocket or by a belt loop on his belt. Figure 1 shows a self-rescuer carried on the belt. Figure 2 shows a miner using a self-rescuer. Figure 3 gives details of design and construction and also descriptions and specifications of the various parts. FIGURE 1.-Self-rescuer in case, carried on miner's belt The self-rescuer is a small canister made of tin plate, to which a mouthpiece is directly attached. The wearer breathes by mouth and through the selfrescuer; breathing through the nose is prevented by a pinch clamp or nose clip on the nostrils. Both the nose clip and the self-rescuer are kept in the case, and a short cord between them keeps the nose clip from being lost. HOW THE SELF-RESCUER OPERATES When the self-rescuer is put in use the air the wearer breathes passes through certain essential parts and materials, described in order with reference to Figure 3. First, inhaled air enters through small holes in the canister at the lower side (as held in the mouth) and then filters through absorbent cotton, held between wire screens, which removes smoke. Next is a layer of granular (14 to 20 mesh size) fused calcium chloride (90) cubic centimeters or 51⁄2 cubic inches in volume), to absorb water vapor, which is always present in air and destroys the efficiency of the "hopcalite," the material in the next layer. Hopcalite is a granular (14 to 20 mesh size) mixture of specially prepared manganese dioxide and copper oxide; 110 cubic centimeters (634 cubic inches) are put into the canister. This layer is separated from the calcium chloride by wire gauze. Hopcalite acts as a catalyzer; that is, it causes any carbon monoxide (CO) and oxygen (O2) in the air that passes through it to unite and produce the relatively harmless carbon dioxide (CO2). The life of the self-rescuer depends upon the length of time moisture is kept out of the hopcalite; for this reason the canister is kept in its air-tight sealed case until it is used. Next to the hopcalite is another filter of cotton between wire screens. The last FIGURE 2.-Miner wearing self-rescuer screen has a cross crimped into it diagonally from corner to corner, so that a space for the passage of air is provided between the filter and the tin-plate back of the canister. The air then passes through a mica-disk check valve to a passageway connecting to the mouthpiece. Exhaled air goes through the same passageway and through an exhale valve (mica-disk check valve) at the end of the selfrescuer opposite the mouthpiece. To prevent any carbon monoxide from leaking through the exhale valve and being breathed by the wearer, the mica disk seats against |