Evening capital. (Annapolis, Md.) 1884-1910, 1886-12-01
coAl. MINING IN GREAT BRITAIN.
Two Recognized Methods OF working
Out c"al-Dangerous subsidencc.


Two Recognized Methods OF working
Out c"al-Dangerous Subsidencc.
The alarming subsidence which took
place some time ago in Scotland, on the
North British railway, near Prestonpans.
and which was fortunately unattended
by any accident, has doubtless added
fresh source of fear to the nervous rail-
way passenger. That the permanent
way of a railway for distance of about
fifty yards should suddenly sink to the
extent of two feet is almost incompre-
hensible at first; and had this subsistence
occurred while the train was passing, in
stead of Immediately afterward, the
consequences might have been dis
astrous. 1t is the case, however, though
it may not be generally known. that
ubsidences-fortunately only gradual
and comparatively inapprcciable--are
taking place over many of our railway
lines, and that minerals are actually
being extracted from underneath nearly
every line of railway under which there
is any mineral to get.
There are two recognized methods OF
working out coal. The old method is
what is known as the sstoop-and-room"
or pillar and-room' system; and the
method introduced into Scotland about
the beginning of the present century is
known as the "longwalt' or shropshire"
system of working. The first system
explains itself by its name. After the
bed of coal is struck "rooms" are worked
out, leaving "pillars" or .stoops" TO sup
port the superintendent strata. The OBJ
ject to be attained in this system, as
practiced in the olden times, was to
have large room worked out, and as
small stoop or pillar of the coal itself
left. as was consistent with the safety Of
the mine and the support of the surface,
while the mine was open.
But this system entailed the entire
loss of the pillars 50 left. To obviate
this loss, the method now generally
adopted is to drive narrow rooms or
passages, seldom exceeding fourteen
feet, through the seam, leaving large
pillars-about % per cent of the min
eral-until the extremity of the availa-
BILE coal is reached. When, however,
no regard is to be had for the surface,
and the coal has thus worked out as far
as can be done, the miner commences to
work backward, taking out the stppps or
pillars as he goes. The whole roof of
the mine then comes down; and this is
the most dangerous kind of subsistence.
1t does not take effect Immediately above
the place where "stooping" has been GO
ing on, but it also "dfaSvs"1 round
about it.
The "longwall, or Shropshire method
of working, is what is known as the
system of complete excavation; that is.
the miner takes out the whole coal as he
proceeds leaving perhaps only foot of
the roof, should the everything strata be
soft, and props up passage with wooden
supports as he proceeds, to enable him
to keep an open way to the face Of the
coal. The portions worked out are
packed on each side of the "road" with
the waste material taken out with the
coal. This method of working, though
it necessarily implies subsidence, is on
the whole the safest for the surface, and
is generally the one adopted. In fact,
as mineral landlords are paid, in lieu Of
rent, a royalty or lordship on every ton
of coal or other mineral brought to the
surface, and as the tenant can more
quickly extract the mineral by the
wooden prop method, he is generally
bound in his lease to work in this man.
ner, when practicable. Chambers JourA
nal