Los Angeles herald., 1909-02-15
TUNNEL WORK
FORCES AHEAD
ELIZABETH LAKE SECTION
SETS THE GAUGE
AMERICAN RECORD FOR ROCK
DRIVING ESTABLISHED
Most Improved Machinery Employed
and Every Effort Made to Fin-
ish Within Schedule
Time

that the time required to construct the
Elizabeth tunnel, the length of which
| is 26,S60 feet, under the crest of the
Coast Range near the Elizabeth lake,
would be the factor which would de-
termine the length Of time required ia
complete the Los Angeles aqueduct. 1t
Is by far the longest tunnel on the en-
tire route, the next longest tunnel be-
ing about 5000 feet long.
In order to finish this tunnel within
the five years a progress of eight feet
per day from each end of the tunnel is
J required to be made continuously.
i Work was begun at the south end of
this tunnel in October, 1907 and on the
north end in November, 1907. The en-
glneers did not wait until all the me-
| chanical equipment for driving the
| tunnel could be obtained and installed,
but began the work by hand, the
! equipment being gradually installed
! and the plants built up to a final state
Of completion in April and May, 1908.
| The judgment of the engineers as to
| this tunnel being the controlling fac
tor in the completion of the work has
| been demonstrated as construction has
proceeded. 1t will be possible to OPEN
| UP the remaining portions Of the work
| in so many places that it can be fin
lshed at practically any speed required,
| dependent somewhat upon the capacity
|
cement to line the aqueduct at the
rate of excavation, and also somewhat
dependent upon the time when the
railroad is completed along the north
ern portion Of the ditch so as to fur
nish economical transportation faciI-
! tiles.
The accompanying diagram in hori-
Zontal scale represents time, and in
| the vertical scale it represents the dis
lance run during any interval Of time
! i'll question. In order to be on the
schedule of eight feet per day, the ir-
regular line showing progress should
coincide with the straight inclined line
! showing required progress.
Bad Ground Encountered
On the north end of the tunnel, from
April to October, 1908, bad ground was
encountered at various points, which
! materially reduced the rate of speed.
| ON account of large amount of water
| being encountered in the tunnel in the
month of August, work was stopped
| there during portion of August and
September while this water was
| drained out. This difficult ground has
now been passed, and it will be OBJ
served on the diagram that since then
! the rate of progress has materially in
creased, and that the progress is now
approaching the schedule required. In
order to overcome the disadvantages
] a
was sunk 5000 feet south of the north
portal, and excavation is now being
| carried on in both directions from this
| shaft, as well as from the portal head
| ing itself. This shaft really puts the
engineers on schedule time as far as
the north portal is concerned, and
| during the past two weeks a progress
has been made south from the Shaft
| under the direction of G.. H. Richards
of thirteen feet a day.
AT the south end of the tunnel the
diagram clearly shows the effect of
putting in machinery and running a
| tunnel lin that manner, instead of by
hand. The change in rate Of progress
occurs about the first Of May as in
dictated on the diagram. The American
record for fast driving in rock tunnels
was made at this south end of the
tunnel in October, 1908, when 466 feet
were made in thirty-One days, or at
the rate of about fifteen feet per day.
| The heading from the south portal is
now within about 325 feet of being on
schedule time, with the probability that
by the first Of April the schedule will
be reached. At the south portal the
rock has been very uniform and salts
factory to work in, although quite hard
1t is known as gneissoid granite.
Duplicate Machinery
The tunnel is equipped at both ends
| with duplicate machinery, so that, in
case of breakdowns, other machines
can Immediately be put into commits
| sion. The muck, or broken stone, is
hauled from the tunnel in trains with
| electric locomotives. The tunnel is ven
tilated, after shooting, with eighteen
inch ventilating pipe, operated by what
are known as positive rotary blowers.
| The tunnel can be cleared of powder
smoke in about twenty minutes after
the shooting. Very advanced methods
are being used in this tunnel excava-
tfon. For instance, mucking machine
is now. being tried out, the purpose of
which is to load the broken rock, after
the firing, into the cars mechanically.
1t has been found that this muck can
be cleaned up with a mechanical muck
er in about so per cent of the time re-
! quired to clean it up with shovels. It
is hoped that this machine will permit
/ of increasing the rate of progress ma
terially, because the greatest delay
| which occurs in driving the tunnel
comes from the cleaning up of this
muck
i At present the city Of Los Angeles
! holds the American record for fast tun-
mel driving, but the Swiss engineers
held the worlds record in the driving
of the famous Simplon tunnel under
| the Alps. The engineers of the aque-
duct are in hopes that by means of this
mechanical mucker they may be able to
attain the Swiss record before the COM
! pletion of the work.
/ One of the interesting features in
connection with the driving Of this
tunnel is that the men are paid a
bonus. They are told that the esti-
mated rate of progress is eight feet d.
day and that for each foot that this
eight feet per day can be exceeded each
man engaged in driving the tunnel will
receive a bonus of 40 cents. The min
ers themselves enter into the spirit of
the game with the same zest that d
team of football players shows in an
| intercollegiate game. 1t is an interest
\ ing fact that during the month Of Oc-
I tober when these men were breaking
the record, the various shifts would
not take time to come out Of the tun-
mel for their lunches. The shifts work
eight hours each, and there are three
of them so that the work is carried on
| continuously.
A Painful Interruption
ssCt11n1Tn prfOrd went IInOn his roof +ho