The Journal of Explosives Engineering - January/February 2022 - 24

100 years ago
S. Shepperd, Vice-president and General
Manager, with M. R. Keefe, General
Superintendent, R. H. Keays, Assistant
General Superintendent, and G. H.
Hines, Chief Engineer.
Lack of space prevents detailed description
of the method employed in
driving this tunnel. It must suffice to
say that all headings are driven by top
heading and bench method, mucked
by hand except Shaft No. 6 and north
end of Shaft No. 7, which are full-face
headings; these are machine mucked on
account of the treacherous and unstable
nature of the rock. Of the twelve headings,
nine are now being timbered.
It has been my observation that comparisons
with regard to speed on public
work are deceiving and odious. On no
two undertakings of similar character
are conditions alike. There are so many
variable factors, such as supply and spirit
of labor, proximity of work to points of
material supply, condition of roads over
which material is hauled, and so on, that
while the Ulen Contracting Corporation
would not suffer by any comparisons, it
will not be necessary to dwell at length
on this. Suffice it to say that the Board
of Water Supply monthly figures indicate
that the maximum monthly excavation
in twelve headings was 6,593 lineal
feet; the maximum weekly excavation in
twelve headings was 1,362 lineal feet;
the maximum monthly excavation in any
one heading was 608 lineal feet; and
the maximum weekly excavation in any
one heading was 148 lineal feet, all on a
two-shift basis. The average advance in
heading per shot is now slightly in excess
of nine lineal feet, and the maximum has
run frequently as -high as fourteen feet
and over.
From January 1,1921, to January 1,
1922, 47,370 lineal feet of completed
trimmed tunnel was excavated, which,
so far as is known, is the world's record.
The headings are now being operated
on a two-shift basis in Shafts 1, 3, 4 and
5, a swing shift in Shaft 6, two shifts
south of Shaft 7, and one shift north
of Shaft 7. It is expected that they will
" hole through " between Shafts 5 and 6;
4 and 5, and in the south end of 7 in
April of this year when the lining will be
started.
Work of this character does not lend
itself to employees' welfare work so well
as in large industrial plants where labor
is more or less permanent, of a different
class, and where there is not a large
turnover. The very nature of the living
conditions-with housing facilities of a
temporary character-precludes welfare
work of the kind you expect to find in
large industrial centers. All the camps,
however, are built along the most modern
lines. The sanitary regulations, and
the policing of these camps are supervised
by the Board of Water Supply, and
the living conditions of employees are so
favorable that the rate of mortality and
sickness so far is less than in New York
City itself.
The method employed in drilling and
blasting is the same as that ordinarily
found in tunnel excavation of this character.
In general, ten-line holes are drilled
and eight relief holes, all eight feet deep,
and six cut holes, all nine feet deep. Du
Pont low-freezing 40 per cent and 60
per cent Gelatin, 11/4 x 8 are used with
Du Pont No. 8 Electric Blasting Caps and
other accessories manufactured by or for
E. I. du Pont de Nemours & Company,
Inc. The holes are fired at 7 o'clock in
the morning and at 5 or 6 o'clock in the
24
The Journal of Explosives Engineering
January/February 2022
The Journal of Explosives Engineering - January/February 2022

Table of Contents for the Digital Edition of The Journal of Explosives Engineering - January/February 2022
