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

194 REPORT OF THE INSPECTORS OF MINES. Off. Doc.
the other section of the i)iHur aud proceed in this manner until a point
is reached twenty yards above the monkey, or about twenty-eight or
thirty yards above the gangway; at this point, props a little stronger
are put about four feet apart across the two breasts which are covered
with round poles forming a battery.
In due time, if the top does
not squeeze aud fall after the first pillar is taken out in the manner ali-eady
described, the second pillar is taken out. If the top does not
fall, then the third and even the fourth pillar is taken out, if necessary,
leaving a space of 20()x.3()U feet, more or less, according to circumstances.
\Vhen the top in these openings does subside, owing to the
number of props used, it comes down so easily that hardly any concussion
is felt in the gangway below. When the top rock has fallen and
filled the open space, a small buggy road is laid at the back of the
fall to take the balance of the coal which was left to secure the surface.
This coal has to be buggied and dumped into one of the breasts
used for that purpose; all the other coal runs by gravity to the main
gangway below, where it is loaded into the mine car. Where the
pillars between the first and second lifts are taken out as shown on
sketch, the rock taken from the gangways and breasts in the upper
lifts is dumped into these openings, forming a pillar of rock instead
of the coal, which has been taken out. The props and timber for
securing the breasts driven up from the second lift are taken down to
the first lift gangway and from there distributed and taken down as
required below\
The props to secure the breasts for taking out the
pillars in the third lift are taken down to the second lift and for each
additional lift the props would be brought down to the gangway in
the lift above until the basin would be reached. Although this
method of mining and robbing pillars has been in practical use at this
colliery during the last two years, not one fatal or serious accident
has occured in the sections which have been robbed. I am convinced
that thousands of tons of coal have been taken out which would have
surely been lost, if the old system of skipping and robbing pillars had
been adopted. I have examined the inside workings at this colliery
and watched the progress of this work very closely during the last two
years, and I must say that I honestly believe that 90 per cent, of the
coal has been taken out of all the places robbed and finished.
In looking
over former mine Inspectors' reports, I came across the one issued
for 1887, in which Mr. William Stein, mine Inspector, of Shenandoah,
Pa., for the Sixth District, makes a favorable mention of Mr. John L.
Williams' plan for the filling of large openings in
the Kohiuoor Colliery,
at Shenandoah, with culm, in order to save pro])erty and lake
out more coal in the robbing of the Mammoth seam, where it is (hick.
Since then, the jilan has been adopted and works successfully all
through the anthracite region. In my report for the year 1897, ten
years after the time Mr. Stein wrote his report, I have no hesilalion in
saying that Mr. Williams may well feel i)roud of another undertak-