SINGLE DISTRIBUTION

The single distribution system was developed at the Creighton coal works of the Pittsburgh Plate Glass Co. at Creighton, Allegheny County, Pa., and was seen in use there by the writers.

FIGURE 9.-Miner wearing a self-rescuer taken from the cache, Penelec No. 5 mine. (Note the discarded metal case)

The mine is large, about 250 men working underground. The company provides a self-rescuer for every man and gives it to him inclosed in a small, close-fitting, wooden case made of one-half-inch stock and having a glass cover. The extra case serves as additional protection for the self-rescuer. A small brass plate with stamped numbers is soldered to the self-rescuer brass case on the side seen through

the glass. These numbers correspond to each miner's check and also to the number of his lamp. The miner takes care of his self-rescuer, moves it when his work is changed to another place, digs the hole in the rib (7 by 14 by 7 inches deep), and is held responsible for keep

FIGURE 12.-Situation of miners' self-rescuers in necks of rooms being worked in a section of Creighton coal works

ing it in good condition and having it convenient to his work. How the miners' self-rescuers are placed with reference to working places and the adjacent parts of the mine is shown in Figure 12. The rooms have a maximum length of 250 feet, so the miner can not be more than that distance from his self-rescuer while he is at work. Figure 13 shows a miner taking the self-rescuer from its hole.

At the Creighton coal works the machine runners, locomotive drivers, track men, shot firers, and others whose work is not at one place carry their self-rescuers with them. Figure 14 shows the operators of an undercutting machine and their self-rescuers, in individual cases, the same as those for the miners, carried in the tool box of the

FIGURE 13.-Miner taking self-rescuer in its wood and glass case from hole in pillar at room neck, Creighton coal works. (Explosives box above man)

machine. Locomotive drivers carry their self-rescuers in wood and glass cases on top of the locomotive, as pictured in Figure 15. Track workers carry self-rescuers, without wooden cases, on their belts; Figure 16 shows two men with self-rescuers. Shot firers at this mine also carry their self-rescuers on their belts, as shown by Figure 17.