When the scraper must be moved from one room to another it has to be dragged by hand, and much time is lost in rearranging the scraper and the ropes. The crew employed on this work ordinarily consists of a miner and a laborer for shooting the coal, two or three men handling the scraper, one man on the hoist, and a man on the mine cars loading, a total of six or seven men. The investment is increased by the cost of building the extra chutes and by the time lost in transferring the scraper from room to room. The production of coal is approximately three cars (capacity, 95 to 107 cubic feet) or less for each man employed.

Bed mined.—The Hazlebrook Coal Co., at its Raven Run colliery, Raven Run, Pa., has developed a system of scraper-chute mining which obviates some of the bad features noted at other collieries in the region. This colliery uses scrapers to mine the Little Buck Mountain coal bed, which has a roof of hard, white sandstone 10 to 60 feet thick, a floor of soft fire clay, and a 3-foot vein of very hard coal of the composition given in Table 31. Immediately over the Little Buck Mountain bed is the Buck Mountain bed, which had been first mined in this section.

Table 31.—Analysis of coal from Little Buck Mountain bed

Mining methods.—The territory the writer visited was in virgin coal. Gangways and airways are driven as the accompanying map (fig. 28) shows. A set of chambers is started on 120-foot centers. An opening having a chute approximately 10 feet wide is driven in about 20 feet from the gangway, then three breasts are turned off, the center breast going at right angles about 45° to the right and left; next the two side rooms are turned and driven parallel to the center breast. These three rooms are supposed to be driven on 40-foot centers with the rooms 22 feet wide, leaving 18-foot pillars.

A hoisting engine is installed at the mouth of the chute in the space provided at the gangway, as the sketch of the end of the chute shows. This engine operates the scrapers in the room, bringing the coal from the three rooms to the one chute. Light one-man

Only two men are employed in addition to the engineer operating the hoist—one is a miner, the other a laborer. The miner's whole time is spent in drilling holes and shooting and placing props. The laborer does all the handling of the scraper, but when the scraper is changed from one room to another the miner assists the laborer. The scraper is then brought down to the chute. The jack is removed from the face of the room in which the scraper has been operating and placed in the face of the room in which the scraper is to work. The ropes are then put in position, and the scraper is ready.

Operating data.—The engineer on the hoist runs the scraper, places the mine car under the chutes, and shifts the cars as they are loaded. Thus the need of a man on the gangway is obviated. With an outfit of this character the Raven Run colliery is each day obtaining coal amounting to three cars, with a capacity of 120 cubic feet each, per man employed. The cost of building extra chutes and of having a man in the gangway is saved. Use of the small scraper saves handling by an extra man, as the scraper is so light that a laborer can handle it easily at the working face. The miner in charge can therefore devote his time to shooting the coal and putting up props to make the working places safe.

Only one jack is used, and ordinarily it is only moved once in cleaning up the coal in the chamber. No special signal device is employed. When the laborer wishes the scraper moved, he signals the hoisting engineer by pulling the slackened main rope twice. This system of scraper operation is the simplest in the anthracite region and seems to give results better than the average.

STRANGE SELF-LOADING SCRAPER

Many types of scrapers have been designed for use in coal mines. One of the most interesting is the Strange scraper, which is rather widely used in the mines of the Pine Hill Coal Co., near Minersville, Pa. This scraper consists of two steel sides properly cross braced on top. A door is hinged on the bottom of the rear end. As the scraper advances up the chamber the door in the rear end is opened by a system of ropes and chains and acts as a shovel when it enters the pile of loose coal at the face. Quick reversal of the hoisting engine closes the door quickly and throws the coal that it has picked up into the scraper; then the scraper is pulled back again to the coal pile, and the process is continued until the scraper is loaded. When the scraper is loaded, it is started down the chamber; the door closes automatically, keeping the coal in the scraper.

Bed mined.—This scraper was seen while in use in the mines of the Pine Hill Coal Co. Table 32 gives a section of the Seven Foot bed

Only two men are employed in addition to the engineer operating the hoist—one is a miner, the other a laborer. The miner's whole time is spent in drilling holes and shooting and placing props. The laborer does all the handling of the scraper, but when the scraper is changed from one room to another the miner assists the laborer. The scraper is then brought down to the chute. The jack is removed from the face of the room in which the scraper has been operating and placed in the face of the room in which the scraper is to work. The ropes are then put in position, and the scraper is ready.

Operating data.—The engineer on the hoist runs the scraper, places the mine car under the chutes, and shifts the cars as they are loaded. Thus the need of a man on the gangway is obviated. With an outfit of this character the Raven Run colliery is each day obtaining coal amounting to three cars, with a capacity of 120 cubic feet each, per man employed. The cost of building extra chutes and of having a man in the gangway is saved. Use of the small scraper saves handling by an extra man, as the scraper is so light that a laborer can handle it easily at the working face. The miner in charge can therefore devote his time to shooting the coal and putting up props to make the working places safe.

Only one jack is used, and ordinarily it is only moved once in cleaning up the coal in the chamber. No special signal device is employed. When the laborer wishes the scraper moved, he signals the hoisting engineer by pulling the slackened main rope twice. This system of scraper operation is the simplest in the anthracite region and seems to give results better than the average.

STRANGE SELF-LOADING SCRAPER

Many types of scrapers have been designed for use in coal mines. One of the most interesting is the Strange scraper, which is rather widely used in the mines of the Pine Hill Coal Co., near Minersville, Pa. This scraper consists of two steel sides properly cross braced on top. A door is hinged on the bottom of the rear end. As the scraper advances up the chamber the door in the rear end is opened by a system of ropes and chains and acts as a shovel when it enters the pile of loose coal at the face. Quick reversal of the hoisting engine closes the door quickly and throws the coal that it has picked up into the scraper; then the scraper is pulled back again to the coal pile, and the process is continued until the scraper is loaded. When the scraper is loaded, it is started down the chamber; the door closes automatically, keeping the coal in the scraper.

Bed mined.—This scraper was seen while in use in the mines of the Pine Hill Coal Co. Table 32 gives a section of the Seven Foot bed