The West End of the Tunnel comprises the brick arch and portal,
well No. 4, the supplementary shaft, and what is known as the West
Shaft. The brick arch has been driven through what is aptly termed,
“demoralized rock,” for immediately after the spring thaw it becomes a
quicksand, and spews into the tunnel from every direction. By driving
small adits on each side, and a central adit some distance ahead of the
main tunnel, Mr. B. H. Farren overcame this dangerous and difficult
work, which at one time threatened his contract, and thus enabled
the arch work to be carried on. Subsequently, the central adit was
carried through to the West Shaft, and thus the costly and difficult
task of lifting 420 gallons of water per minute, to a height of 320
feet, was avoided, and it now escapes by natural flow through the west
portal. Drilling is practised here as described for the East End and
Central Shaft; in the East End the heading is driven on grade, and the
overhanging enlargement is “stoped” out by hand drilling worked from an
arched stage, (see plate opposite page 85) thus avoiding the necessity
of handling twice; mules draw the laden trucks, from the heading
and beyond where this stopeing out of the roof is going on, to the
locomotive, which hauls a train of cars laden with stone to the dump.
At the West End, however, the roof of the heading is driven in line
with the roof of the tunnel, which is hereby left complete as the
heading progresses; this involves trucking by hand, and dumping the
rock from the heading over the bench to the lower level, see plate
opposite page 90, and is not found so economical as the East End
method. These differing methods of working, however, were not started
simply as experiments, but for good engineering reasons; at the East
End, the dump was ample below the grade of the outlet, whereas, at the
West End there was no opportunity to get out at the portal, on the line
of the intended railroad; all the rock here had to be lifted (until the
portal and arched work were completed) up and out of the West Shaft,
and dumped on to the mountain side, and, to avoid being impeded by
water, the heading was driven on a level higher than the grade of the
Tunnel, thus ensuring good drainage for the most important part of the
work, as it was then deemed, viz.: monthly linear advance. For the
Commissioners were servants of the public, and the advance, rather than
the enlargement of the Tunnel, was the measure of their success so far
as public opinion was concerned.
Public-domain text, read in full here on John Shaqi.
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