Amador ledger. (Jackson, Amador County, Calif.) 1875-19??, 1906-12-14
PR0L0NGING THE LIFE
OF MINE PROPS.

One of the biggest expenses con-
nected with coal mining is found in
the mine tlmbers used to support the
various gangways. Their destruction
by decay and breaking costs many
hundreds of thousands of dollars
annually, and IN some cases the loss
of human life. Mine operators are
fully familiar with these losses. They
know also that the seasoning and the
preservative treatment of timber add
to its life in service in the mine.
But it has only recently been estab-
llshed by experiment that effective
seasoning and treating with creosote,
carbolinium and zinc chloride as wood
personalities can be secured at a cost
so slight in proportion to the greatly
increased life of the props as to effect
a material saving. The experiment
carried on during the past few months
by the Philadelphia and Reading Coal
and Iron Company, at its collierIes
near Pottsville, Pa, under the direc-
ton of member of the Forest
Service, has resulted in an economy
which demonstrates that the preserva-
ton of mine props can be put on a
firm commercial basis.
In the loss of mine timbers at lest
60 per cent are destroyed by decay
and the remainder by crush. The
percentage charged. to decay should
be even higher, because many of the
timbera which break have already
been weakened by decay. Decay is
probably the cause of 70 per cent of
all failures in mine timbers.
Decay in pl ops is principally caused
by wood destroying fungi. Warm,
moist air, together with certain gases
always found in mines, greatly favors
the development of these fungi.
Ventilation is an enormous factor.
Timber in the vicinity of shafts and
slopes where there is abundance of
fresh air lasts longer than that deeper
in the mines. The variation of
moisture and temperature within
mines is so wide that timbers may
decay in eight months or may last
several years. Timbers that are con-
stantly dry last longer than those
to an alienation of these
Insects play very considerable
part in the destruction of mine tim
bers. Many forms are found, in
bark boreres, ants and timber
worms. Their presence may be due
to allowing logs to lie unpeeled for a
considerable time after telling.
Insect infested timber is frequently
overlooked by the inspectors and
to go inside the mines. Ants
and cerambycid borers may attack
props after they go IN the mine.
There decay spreads rapidly, and the
destructive work of the insects
the lack of light or by presence of
gases. Creosote and carbolinium are
effective Insecticides and stop the
work of the wood borers.
A mine prop is composed of three
parts, which together form ''set"--
two uprights, called legs, across the
top of which is a crosspiece, called a
collar. After a prop is decayed
sufficiently to necessitate its removal,
it is replaced. At times, when only
one leg is decayed, that leg alone is
removed and replaced by new one.
however, the whole set is
and this Involves the de-
struction of all the logs by saving
them in two to remove them.
Various materials and methods for
preservative treatment have been
tried, and up to the present time all
have proved efficient. Only time will
show which are the most satisfactory
from the practical point of view
with a brush, creosote and
carbolinium give an excellent pene-
tration in solid wood, frequently
averaging from one-fourth to one-h half
an inch. The amount of oil that
seasoned loblolly pine takes from a
brush application is surprizing,
in the end grain. Little
difference in penetration has as yet
been noted between creosote and car
tolinium, tho the latter seems better
on absolutely green timber. All
brush treatments were applied hot
and in two coats. The second coat
absorbed practically as much oil as
the first.
Opentank treatment has succeeded
beyond all expectations. This con-
sists of an immersion of the timbers
for several hours in preservative and
then allowing them to cool to atmos-
pheric temperature. While the FEAST
bllity of the open-tank treatment has
been demonstrated, there is much yet
to be learned. The cost may be re-
duced by shortening the immersion
and thus consuming less fluid. A
very heavy treatment is not necess-
any. The best preservatives Eapproxi
mately double the serviceable life of
railway ties and may be counted on
to do the same or better for mine
props. Seasoned and treated props,
which we're put in alongside of the