The daily sentinel., 1909-01-16
TIMBER in
THE MINES

terestcd in mining realize the
| extent to which timber is used in
this very important industry"
said n government expert in pre-
seryation of mine timber who
| has just returned to Washington
| from the West. THE average
| man has only n vague UNDER
| standing of the importance of
thc part that timber plays in
the mining industry, and seldom
| thinks OF the enormous guam
titles required each year to pre-
| vent the caving of the over
hanging ground and to keep
clear the main working pas
sagcs of mines.
There are two general classes of
such timbers," he continued, the
first Is used in bracing the Slopes as
they are called, where the ore is be-
ing taken out. As the ore is mined
the surrounding rock is held in place
by bracing it with heavy timbers.
framed into rectangular sets When
ore directly above the first set is re-
moved. a second set is built i'm on
top, and so on. The service of these
timhers ends when the ore is ex-
hausted and the active mining trans
ferred TO another vein or ore-body.
y.
to a point where the pressure of the
rock walls crushes them, and cave
in occurs, This causes no damage
If, as / have said. the mining work
has been finished but it sometimes
heppens that decay has weakened the
tin bers to such an extent that the
cave-ia occurs prematurely, and tier
lives are sacrificed. In such cases the
remaining ore is also a loss, for
when the ground has once commenc-
ed to move or work as the miners
call it. it is almost impossible to
clean II out and hold back the rock
so that the remaining ore may be
obtained.
But of still greater importance is
the second class of timbers used in
the main working openings, tunnels,
shafts, etc. which are to be main
tanned for as long a time as possible.
Timbers for this service are chosen
not only for their strength and firm
ness, but also for their ability o re-
sist decay.
In nine eases out of ten, when
timbers are crushed. the Indirect
forms of plant life. The dwindling
of our timber supply has driven con-
sumers of wood all over the country
to study decay and its prevention.
and 1t is safe to say that in the very
near future we shall see many more
mines putting in small plants for the
treatment of their timbers after the
pattern of the plants that have been
designed and installed for this pur-
pose by the United States forest SER
vice. BY treating tac por:-a.-e-a,
with some one of the vario- rs
preservatives, they may be made to
resist decay almost indefinitely. The
additional cost is slight
Not only this. but since timber
when it is once treated retains its
strength. many of the So
called inferior timbers' which have
hitherto been considered almost
valueless because they decay rapid
ly, will find use in many localities.
Such species are loblolly pine and.
to certain extent, shortleaf pine.
spruce, fire-killed lodge
pole pine, white fir, and many other
local timbers
for mine timbers was put up by an
eastern coal company, after extensive
in cooperation with the
forest service which demonstrated
the practical value of the treatments.
Since then, other plants have been
installed in different parts of the
country, two of the latest being in
the Couer d 'Alene lead district of
northern Idaho. where, while there
is an ample timber supply for some
time to come. the treatment is war
ranted by the high labor cost of re-
placing timber sets. The added cost
of treating timbers is from 10 to %
per cent of the original cost"