The Ocala banner. (Ocala, Marion County, Fla.) 1883-194?, 1909-02-05
IMPORTANT PART TIMBER PLAYS
IN PRODUCTION OF MINERAL
WEALTH

portant INDUSTRY said a government
expert in preservation of mine tim
Der, who has just returned to Wash
ingtOn from the west. The average
man has only a vague understanding
of the importance of the part that
timber plays in the mining industry,
and seldom thinks of the enormous
quantities required each year to pre-
vent the caving of the Over-hanging
ground and u keep clear the main
working passages of mines.
There are two general classes Of
such timbers," he continued. The
first is used in bracing the SLOPES as
they are called, when 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 in on
top, and so on. The service of the
timbers ends when the ore is eX-
hausted and the active mining trans
ferred to another vein or ore-body.
After a time these timbers decay,
f0o a point where the pressure of the
rock walls brushes them, and cave
in occurs. This causes no damage if,
as I have said, the mining work has
been finished; but il sometimes hap
pens that decay has weakened the
timbers to such an extent that the
'cavein' occurs prematurely, and then
lives are sacrificed. In such cases the
remaining ore is also loss, for when
the ground has once commenced to
move, or work, as the miners call il,
it is almost impossible to clean it 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 maintain
ed 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 to re-
sist decay.
In nine cases out of ten. when
timbers are crushed. the indirect
cause is decay, produced by low forms
of plant life. The dwindling Of our
timber supply has driven consumers
of wood all over the country TO study
decay and its prevention. and il is
safe to say that in the very near fu-
ture we shall see many more mines
putting in small plants for the treat
ment of their timbers. after the pat
tern OF the plants that have been de-
signed and installed for this purpose /
by the Unietd States forest service. !
BY treating the permanent timbers
with some one of the various presery- /
atives. they may be able to resist de
cay almost indefinitely. The addition
al cost is slight.
Not only this, but since timber.
when il is once treated. retains its or
iginal strength. many Of the sO-called
inferior timbers which have hitherto
be considered almost valueless be-
cause they decay rapidly, will find
wide use in many localities. Such
species are loblolly pine. and, to a
certain extent. shOrtleaf pine, Engle-
mann spruce, fire-killed lOdgepOle
pine. white FIR, and many other more
local timbers.
"The first of the treating plants for
mine timbers was put up by an east
ern coal company, after extensive ex-
periments in cooperation with the
forest service, which demonstrated
the practical value OF the treatments.
Since then other plants have been in
stalled in different parts of the coun-
try, two of the latest being in the
Occur d'Alene lead district of north
ern Idaho, where. while there is an.
ample timber supply for some time.
TO come, the treatment is warranted
by the high labor cost of replacing
timber sets. The added cost of treat
ing timbers is from 10 60 % per cent.
OF the original cost
An interesting point in the problem
of wood preservation is the spread of
decay in old workings, caused by in
lection from nearby timbers. A
fresh green post, placed between two
sticks that are already sick will be-
come infected and decay much more
rapidly than if it were isolated. The
cOntagion is similar to that of the ills
that man is heir to. although il usual
ly works more slowly. In one large
mine a twO-mile tunnel was completed
eight years ago. and during the first
four years the timber stood up in fine
shape. Then signs Of decay began TO
creep in here and there. and since
then the disease has extended
throughout the entire length OF the
tunnel. neceSSitating an annual py-