of unseating the jugglers is much less than when the breast is opened by two shutes.

To prevent the coal from running out through the shute, the opening into the breast is closed by a "battery" constructed by laying three, four, or five heavy logs across the opening as shown by Fig. 1 Atlas Sheet No. XXIII, or built on props as in Fig. 3, Atlas Sheet No. XXI; a hole is left in the center or at one side of the battery through which the coal may be drawn. The battery closes all of the opening into the breast except the space occupied by the juggler manway, and is made as nearly air-tight as possible by a covering of plank.

Double shute breasts.

When the Mammoth bed is very thick it is frequently worked on steep pitches by opening the breasts by two main coal shutes, each of which is provided with a battery through which the coal is drawn; a manway shute is driven up through the center of the pillar for a few yards and is then branched out in both directions until the branches,-called "Slant shutes,"-intersect the foot of each breast near the battery as shown by Fig. 3, Atlas Sheet No. XXI. The juggler manways are started at this point and continued up on each side of the breast. The main return airway is driven in the solid, through the stumps above the gangway.

In this illustration the gangway is shown driven against the roof,-a plan not generally adopted. When, however, the pitch is very steep the coal in the loading shute is more readily controlled, if the pitch of the shute is lessened by driving the gangway along the top. When this is not done, a gate placed in the shute below the check battery enables the loader to properly handle the coal. Coal in excess of the amount necessary to keep the miner up to the face may either be drawn from the main batteries, or sent down the manways and slant shutes to the manway shute, from which it is loaded through an air-tight check battery.

To give the loader sufficient working room the main shutes are usually eight or nine feet wide, but sometimes only for the first six or eight feet; above this they are driven about

six feet wide by five or six feet high. The manway and slant shutes are driven six feet wide by four to six feet high (measured at right angles to their inclination).

In this plan the miners always have free access to the breast, the traveling-way being entirely independent of the main loading shutes; and the loader is not troubled by the manway coal, as this goes down into the slant shutes, so that he can work at the battery when coal is coming down the manway.

When it is desirable to run the stock coal from the breast as quickly as possible to empty the breast and avoid rooffalls or slides from the floor, the coal can be drawn from both shutes at once. This is an advantage possessed in common by all double shute breasts over those opened by a single shute.

In this and other illustrations reproduced from the Report A2, A is the stump, and P the pillar left between the breasts.

As the number of openings-three for each breast-greatly weakens the gangway stumps and pillars, this plan is best adapted to workings in strong coal.

When the bed is not thick enough to carry an independent airway over the gangway, the shutes are driven up as in the plan just described, for a distance of about ten yards, or until they intersect the heading (airway). The breast is opened out just above the heading, a battery being built in the heading immediately above each shute. A manway is started from the gangway and driven up through the center of the pillar stump until it intersects the heading, and a trap-door is placed at this point to confine the air, and to prevent accidents from objects falling from the heading into the gangway below. This manway is made sufficiently large to be used as a traveling-way and as a passage for timber and supplies,-generally about four by six feet, or perhaps somewhat smaller.

In this, as also in the preceding plan, it is not necessary to drive the main shutes more than six feet wide, but when this width is adopted the lower portion of the shute may be broadened out to about nine feet to give the loader sufficient working room.

In the plan last described the manway coal comes down into the main shutes, and often occasions great annoyance to the loader. The plan is also open to the same objection with the preceding plan of necessitating three openings for each breast.

A further modification of the same plan is effected by replacing the manway driven through the pillar stump by a manway planked off on one side of one of the main shutes. The shute carrying this manway is driven three feet wider than its mate. The manway is protected from coal coming down the breast manway by an inclined plank covering which directs the manway coal into the main shute.

This is not a good plan for use in gaseous workings as it is almost impossible to prevent a very large amount of leakage through manways so constructed

A plan less complicated than any of the above-described methods is shown by Page Plate No. 18.

In this plan the main shutes are driven up to the heading from which the breast is opened out, a log battery being built at the top of each shute at the points marked a a, a a, in the illustration. The shutes are used not only for drawing the battery coal, but they also receive the manway coal, and are used as travelling-ways and for the conveyance of supplies.

In this, as in all of the preceding methods a check battery is placed in the shute to prevent the air current from taking a short cut from the gangway through the shute to the breast airways, and this check battery is of great assistance to the loader when the shute has a very steep pitch, as he can readily control the flow of coal through the drawhole. The drawhole is sometimes closed by a piece of brattice cloth, hung so as to form a flap, under which the coal freely runs.

All of these methods are open to the objection that in case of any accident to the breast manways by which the flow of air is obstructed, there is no means of isolating the breast in which the accident occurs, and the ventilation of all the breasts beyond it is impaired or entirely stopped.