Reports of the Inspectors of Mines of the anthracite coal regions of ...

202 Reports op the Inspectors op Mines. [No. 10,
The following formula has been employed to ascertain the quantity of
water issuing through each bore hole, in which friction is taken into ac-
count :
G=/\/(3d)^XH, in which G=the discharge in gallons a minute, H=
L head of water in feet, L^length of bore hole in
yards, and d=diameter of hole in inches.
Thus, let it be required to find the discharge of hole No. 5, which is 3
inches in diameter, 13 yards long, under a head of 35 f(^et.
—1,—, -^ —=398.7 gallons.
13 yds. 2
Hole No. 5, G= Ax(9)=X35'=5Xlog 9+log 35—log 13 ' .^^^ ^ ^ ,,
Temperature of water, 54° ; temperature in the gangway, 58° ; tempera-
ture on surface, 58°. The section of the line of bore holes was put through
the pillar to tap the water in the Harleigh mines, which had raised at the
time to 45 feet. Previous to doing so, careful observations of the indications
of the water oozing through the pillar had been made, and as the same
increased daily, I concluded to request the company to put in sufficient
pumping capacity, and take the water produced b^'^ the adjoining colliery
by means of the bore holes through the pillar, as indicated on the section,
as I did not consider the barrier pillar strong enough to resist 320 feet
head of water. This, of course, was alarming news to the company, as
they did not anticipate that the caving in of the Harleigh colliery was of
so damaging a character to tteir mines. At my request, Mr. Van Winckle,
president of the company, invited Messrs. C. Pardee, E. B. Coxe, T. S.
McNair to go in the mines, in company with their superintendent, Mr. T. P.
McFarlane, and himself, and get their opinion as to the strength of the
pillar. Accordingly this was accepted, and the party jDroceeded to the
scene, and, after the necessary inspection, they, too, gave it as their opinion
that it was the only remedy to put in adequate pumping capacity and take
all the water. Since, three large pumps have been put in, an account of
which can be seen in another part of this report. Since the water has been
tapped by the bore holes, the water has lowered 20 feet in the adjoining
mines. Before standing the props, a hole, about 5 feet long, was drilled
into the pillar, and a gas tube or pipe, 6 feet long, with a flange on the outer
end, inserted into the hole, after which the prop was stood, and the flange
of the pipe spiked against the inside of the prop. Then the drilling with
the long drill was commenced, and continued at the rate of about 15
feet per hour, by three men, a distance of 45 feet, at which point they
struck water, proving the pillar to be exactly the same as represented by
the maps of these collieries. This is complimentary to Mr. Thomas S.
McNair, C. and M. E., for the accuracy of his surveys.
A slot l^"x5^" was morticed through the side of the props to shut off
the water with a key, in case an^'thing should happen to the pumps.