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

xlii INTRODUCTORY TO Off. Doc.
weight and makes stiffer and better pillars than either the Ross or
the Red Ash. The best pillar is the one that will stay as it was cu t
out until it is disturbed by a squeeze. The Ross pillars at Dodson
and the Red Ash at Black Diamond will not do this. It is their
FRO M
QliLM BANK TO QmyiVii^S
A
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LOADER
CoMvcroKS
No. 5.
Suggestion for Feeding a Conveyor Line.
nature to break down and fill up the empty chambers. Although th(!
Red Ash pillar in Plymouth is nearly three times as high as that of
the Ross, the nature of the coal makes it a tougher and a better pillar.-
Atmospheric changes do not affect this vein the same as they do the
Ross. The Red Ash, above Kingston, is worse for a pillar than even
the Ross at Plymouth. There is from 8 inches to 2 feet of loose stuff
between the vein and the roof at Black Diamond, which runs off th«
])illar until it becomes bare, like a prop without a cap piece, for so
many feet each side. This loose stuff decreases our average very
much and increases the dirt, besides making a pillar valueless. The
owner of ten acres of Red Ash from Plymouth to Nanticoke is better*
off than the owner of twenty acres of Red Ash from Plymouth Junction
to Pittston. The percentage of coal saved by flushing depends
very much on the size of the property also, for when two veins are
less than seventy feet apart, it is necessary sometimes to stop the
party in the upper or lower vein until one is worked or flushed through.
Even in the same vein it is necessary to remove miners when thcii"
chambers are not half done until the surrounding chambers are
flushed. But this cannot be done unless the property is large enough
to allow the required number of chambers for such changes. In some
cases a whole gangway should ])e stopped in order to flush in it a
number of chambers to stand in place of so many blocks of coal and