Daily Kennebec journal. [microfilm reel] (Augusta, Me.) 1870-1975, 1907-01-12
MINE PROPS.
Experiments Fer Proloneing Life OF
in Galleries.

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One Of the biggest expenses connected
with coal mining Is found III I'll" milne
tinIherS used to support the various
gangways Their destruction by decay
and breaking costs many hundreds OF
thousands az dollars annually and iii
some cases the loss of human life. Mine
opera .or@ are fully familiar with these
losses. They know also that the season.
timber add to its life III service in the
mine. But it has only recently been cs-
tatlishcd by experiment that effective
seasoning and treating with creosote
carbolinium. ana zinc Chord as WOOD
presclvatives can be secured at cost 50
slight N proportion to the greatly in
creased lifc of the props as to effect
material saving. The experiment car
the Philadelphia and Reading Coal and
Iron Company at its collieres near
Pottsville. Pa. urdcr the direction of
member of the Forest Service. has re-
suited in an economy which demonstrates
that the preservation Of mine props can
be put on a firm commercial basis.
per cent. are destroyed bv decay and the
remainder by crush, The percentage
charged TO decay should be even higher.
because many of the timbers which
cay. Decay is probably the cause of -
per cent. of all failures in mine timbers.
Decay in props is principally caused by
d-destroying fungi. Warm. moist air.
found in mines, greatly favors the devel-
opment 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 nincS. 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 constantly wet or con-
stantly dry last longer than those sub
iected to an alienation of these condi-
tons.
Insects play. very considerable part
in the destruction Of NINE timbers.
Many forms are found. including bark
borers. ants, and timber worms. Their
presence may be due to allowing logs To
lie unpeeled for 4 considerable time after
| telling. 1nsect-infested timber is fire.
quently overlooked by the inspectors and
allowed to go inside the mines. Ants
and ceraE.byc.d borerS may attack props
after they go in tn" mine. There decay
spreads rapidly. and the destructive
work of the insects appears to be in no
way affected by The lack Of light or by
srcsence of gases. Creosote and car
bolinlum are effective insecticides and
stop the work Of the wood-borers
mine prop is composed of three parts,
which together form "set'-two up
rights, called legs. across the top of
which il; q Crosspicce. called n collar.
After 4 prop is decayed sufficiently I"
nccessitate its removal it is replaced. AT
times. when only one leg is dccayed, that
leg alone is removed and replaced by
new one. Frequently however tie
whole set IS replaced, and this involves
the destruction of all the logs BY saving
them in two to remove them.
Various materials and methods for
pr scrva,tvc treatment have been tried.
ard up TO the Present time I'll hay"
which are the most satisfactory from the
practical point Of view. Annlied with
brush. crcoS0te and c;,rbolnium give an
excellent penetration in solid wood. fra
uUcntiN HvpT1prnC from -CpD,th IN
one-half an inch. The amount Of Oil
that seasoned loblolly pine takes from Il
brush application is surprising. especially
In the end grain. Idttil" difference in
penetration has as Vet been noted be-
tween crcosotc and calbolnium. though
the latter seems better on absolutely
green timber. All brush treatments were
apnlied hot and in two coats The sec
ond coat absorbed practically as much
oil as the first.
Opcn-tank treatment has succeeded be-
yond all expectations This consists OF
an immersion of the timbcrs for several
hours in preservative and then allowing
them to cool to atmospheric temperature
While the feasibility, of the open-tank
is much yet to be learned. The cost may
be reduced by shortening the immersion
and thus consuming less fIu.d. A very
heavy treatment is not necessary. The
tn" serviccable if" Of railway ties and
many be counted on to do the same or
better for mine props. Seasoned and
treated props which were put in
alongside OF the od-stylc props. unsca-
soned and unreclcd, are as sound as
ever while Tho others are already
showing signs Of fungous growth and
decay -
Most Of the props in the colicl.es in
vestisated arc loblolly pine: Pcnnsyl-
vania pitch pine furnishes % per cent;
black and red oak. 10 per cent The
lnbloily pine comes from Maryland and
Virginia. the pitch pine from north