Report of the Bureau of Mines of the Department of Internal Affairs of ...

xxxviii INTRODUCTORY TO Off. Doc.
Best Sized Material.
1. Tlie smaller the material the better. The pillars in the mines
are full of cracks and crevices—sometimes these run half way and
often through the pillars. This depends on the nature of the coal
and the size of the pillars. If these pillars are to be made solid, the
water must carry very small particles of culm, so that they can pass
to the farthest end of these crevices and fill the pillar.
2. The smaller the material the less water will be required to carry
it through. The reason for this is obvious. The larger the material
the more space between the particles and the quicker the water will
travel—it will travel faster than its load. But when its load is
ground from rice size to dust, it is easier for the water to take it along
than to penetrate through and leave it behind.
3. Also, when small material comes in contact with the pipe, it
creates little friction and the pipe will wear better, which is just the
reverse in carrying the larger sizes.
Blocking the Pipe.
A great many think that our culm pipe is a great siphon, witJi
one end in the breaker and the other in the old workings, depositing
its contents in peace. This is a great mistake. It is quite a problem
to run it from one place to another without interrupting the streaui
of culm and prevent it blocking from the face of the mines to the
breaker. When this happens the culm must be taken care of in the
usual manner by taking it out to the bank until the pipe is cleaned
out. This will sometimes take half a day—a day, and sometimes
two days, when a great many lengths of pipe need changing. This
blocking seldom happens with the pipe that carries the small material
from the buckwheat screen, but it will happen to the culm bank
plant pipe about three times a month; and not so often in the pipe
that carries the breaker culm and bank culnl together. This also
proves the importance of having enough good crushers to grind the
culm to the proper size.
Water.
Among the numerous questions in regard to the culm filling, the
most important are those pertaining to the water.
1. Kind of water.—By all means it should be fresh. Dodson gers
its water from the Susquehanna, and the Black Diamond from Toby's
creek. Mining water was tried at both places, but proved injurious
to both pipes and pumps. Whatever may be the original percentage
of sulphur in this mine water, it is increased two fold when it returns
after washing (he culm down the mines.
2. Amount of Water.—This depends on:
a. Distance.—The Dodson culm pipe is 2,.500 feet long, with its
mouth near the bottom of the Ross slope. One and one-half pounds