Columbia gazette. [volume] (Columbia, Tuolumne County, Calif.) 1852-1855, 1854-07-01
TUNNELLING.

ed by the extremely favorable accounts
which have reached us through the
press, in regard to Ahe succeas Of tun-
nelling operations in 0dr Northern
Mines Especially about Forest City
and Iowa Hill. From these accounts it
would appear that as great an amount
as an~average of 20 lbs of gold per day
has been attained by one company, and
divided among its fortunate sharehold-
ers; this amount having been procur-
cd by the labor Of only 5 or 6 hands,
But while accounts of rich results have
reached US, no one up to this time,
through the press or otherwise, has Civ
en- US any definite account of the nature
and formation of these "diggings," and
for one, should be most pleased to re-
eeive some description of the mode Of
operating, the nature of the "diggings, y
the formation of the earth, the length,
size, and cost Of their tunnels, the length
Of time required to construct them, &c.
SO.
Stimulated by the interest I already
feel in the sub ject of tunnelling, and
knowing that the permanency,a least,of
our richer deposits, depend ina inca g.
ure upon developing the riches con-
tanned in the bosom of our mountains,
in com pany with friend, I, few days
since paid a visit to the works Of the
Table Mountain Tunnel Co., located a
bout miles distant from Columbia
and within sight Of jamestown. I was
Indeed greatly surprised to see what an
immense amount of labor hadl been &C
complished, and what an amount of pro-
gress made under circumstances 50 un-
favorable.
This Company commenced operating
about two years since, by tunnelling
through an intervening ledge Of slate
rock, to reach "sink" or deposit of
gravel, on one of the hills of Table
Mountain. This gravel deposit they
were prevented from working by means
Of shafts, in consequence Of its being
contained in basin shaped formation of
the "bed rock :" on the westerly side
| it being hemned in by high hills and on
the easterly by the slope Of the rock
spoken Of, which rises and closes it
around like the rim of basin thus
giving no egress to the water, which,
from being thus confined, would not al
low Of the deposit being worked by
shafts in the usual way. Consequently
they endeavored, from polo below,
to bore through the rock and thus gain
access to this grand deposit, at depth
of about so feet from the surface, the
tunnel meanwhile operating to drain the
gravel bed.
The work commenced two years since,
first penetrating about 200 feet of earth
when the rock was reached, and through
this it was continual blasting, solely,
for about 100 feet more, before the
gravel deposit was reached; when ii
was found they had not struck low G.
Aough to effect perfect drainage
Another tunnel was then commenced,
% feet lower than the first, which, when
completed, will drain the deposit to a
depth Of over 100 feet. This last tun-
mel was commenced in the rock about
one year since, and by prosecuting the
work with great vigor, night and day,
has now reached distance Of 800 feet
leaving about two hundred feet yet to
be pierced through the solid rock, which
is composed mostly Of slate, intermixed
with flint and quartz. The flint is found
in regular perpendicular strata, and is
ofthat degree Of hardness, that work.
ing night and day but FIVE feet of it can
be pierced in weeks labor. The strata
Of slate is nearly perpendicular, -mak-
ing any thing like timbering for the &C.
curity Of the work, entirely unnecessary.
The tunnels are six feet high, and four
feet wide, and are finished in manner
workman-like and secure,-very credi-
table to the Company About one year
has been occupied in constructing each
tunnel,-both being well ventilated with
shafts and pipes, and discharging a
stream Of water sufficient for working
purposes.
This enterprising and pioneer Com
pany Of tunnelling miners is composed
Of l6 individuals, whose faith is so great
in their ultimate success, that they have