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1 000 lb. This involved the consumption of about 3 tons of coal per
hour, during the time the two compressors were rimning (and it is
assumed that they ran most of the time). Only one-twentieth of this
fuel would have been required if electric power had been vised for
traction, power pumps, and blowers.

The shovel plates mentioned reminded one of the tendency, on a
great many jobs, where everything is being sacrificed for speed, to
forget to put them down, or perhaps eliminate them altogether. On
one of the aqueduct jobs, where shovel plates were tried, the same gang
mucked up the same quantity of rock in 30% less time with these
plates than without them.

The cost of making records in driving in relatively small
tunnels is worth studying. In the Catskill Aqueduct tunnel — equiva-



DISCUSSION OX TUNNEL CONSTKUCTION METHODS 489

lent to a single-track railway tunnel — records were sometimes rather Mr.
expensive, as the progress in such a tunnel is limited to a great
extent by the speed of mucking. If the speed is increased the muck
is increased, more muckers are required in a smaller space, and the
men are in one another's way. As an example of this, in one of
the headings of the Walkill Pressure Tunnel, where the progress had
been about 80 ft. per week, each man was handling about 2 cu. yd.
of solid rock in 8 hours. The progress was increased to about 90 ft.,
but in order to do that, the number of muckers was increased, and
each laborer handled about li cu. yd. of solid rock in 8 hours. The
progress was then increased to somewhat more than 100 ft., and each
laborer handled a little more than 1 cu. yd. of solid rock in 8 hours.
In view of these facts, another firm of contractors, carrying relatively
small overhead cost, separated, as far as possible, the drilling and
mucking operations. The firm lost sight of records to a large extent,
and went in for economical tunnel driving. Three gangs of drillers
and three gangs of muckers were used. While the muckers were at
one heading, the drillers were at the other, and when they finished
drilling and shooting one heading, they exchanged headings with the
muckers. The mucking was very efficient. The speaker does not know
how much rock each man handled, but, it was generally considered
as a very economical job.

J. G. Sullivan,* M. Am. See. C. E. (by letter). — The object of Mr.
this discussion is to correct some erroneous accounts and misstate- ^""'^"^°-
ments which have developed in previous discussions. The most flagrant
of the latter was the statement, by Mr. S. A. Knowles, that the credit
for the quick work done at Rogers Pass Tunnel was due to Mr. Mcllwee,
who was the original contractor and was responsible for the methods
and organization. This is very far from the truth. The facts of
the case are as follows:

During January, February, and March, 1913, while the engineers
were working on plans for the building of this tunnel, the writer had
two or three conferences with Mr. Dennis, whose office at that time
was in Winnipeg, and, on March 13th, 1913, he reported his ideas on
the subject to the management of the Company in the following terms :

"Referring to the progress that we hope to make in driving of
Rogers Pass Tunnel. I advised you in my report of October 22d
regarding the relative speeds of driving tunnels on the American con-
tinent compared with those that have been driven through the Alps.
1 have given the matter considerable study since, and have come to
the conclusion that the European method of driving a small lower head-
ing and stoping out the remainder of the tunnel would be too expensive
on this side, on account of the difference in the cost of labor.

* Winnipeg, Man., Canada.



490 DISCUSSION ox TUNNEL CONSTKUCTION METHODS

Mr. "I have been thinking out and studying methods that would tend

Sullivan. ^^ expedite this work. I first thought of driving a heading in the
center of the tunnel, about 9 ft. by 12 ft., and keeping this heading
close to the bench, carrying the air pipes over the muck in front of the
steam shovel and into the heading. I still believe that this method
in rock that will stand, is better than an upper heading. Mr. A. C.
Dennis, however, suggested driving a pioneer tunnel and taking out
an upper heading through shafts into this tmmel, taking out the rest
of the bench with steam shovels. I pointed out to him that this was
impracticable for the reason that from an upper heading you cannot
drill to the bottom of the tunnel, and therefore would have to clean
up all the muck in the bench before you could put in a round of breast
holes to break more rock. I have now made plans showing a combination
of my ideas and Mr. Dennis', which I think is well worth studying.
The plan is to drive a small working pioneer tunnel, 8 ft. by 8 ft.
underneath the main tunnel. I am sending you this for your informa-
tion and, further, if this method should be adopted, that Mr. A. C.
Dennis may have the proper credit for first suggesting a pioneer
tunnel."

This was about a year before the writer ever saw or ever heard of
Mr. Mcllwee. So much for the methods adopted in the construction
of this tunnel.

As to the statement that Mr. Mcllwee was the original contractor:
Mr. Mcllwee never had any contract with the Canadian Pacific Rail-
way Company in connection with this work. In the fall of 1913, the
general contractors sub-let a portion of the work of driving the pioneer
headings and the center heading to Mr. Mcllwee. There immediately
appeared, in some Denver papers, a notice to the effect that Mr. Mcllwee
had a contract for a 5-mile tunnel in Canada. The following is a
quotation from the writer's reiwrt to the Management as to what was
meant by these notices :

"The understanding was that he would bring men from Colorado
and drive the outside pioneer tunnel at so much per foot at a certain
rate of speed. The contractors were to pay him a bonus on any excess
over this specified rate of speed. Contractors to furnish the cars, air,
steel, and all other plant, as I wired you before, the result being that
these men were working at piece work. If they do not make the speed
guaranteed, they can be put off the work and nobody will suffer, as the
entire plant is owned and controlled by the contractor. A man with-
out one cent but brains, can enter into an agreement of this kind, while
it takes capital to enter into a contract to build a five-mile tunnel."

In other words, Mr. Mcllwee, on this particular work, might be
ranked with the grade of contractors kno-\^ai as stationmen on railway
construction work.

In reference to the discussion by Mr. E. Lauchli : Mr. Lauchli, in
attacking this method of doing work, quotes the writer as authority for
prices bid, without giving the full quotation, and leaving an incorrect



DISCUSSIOX OX TUNNEL CONSTRUCTION METHODS 491

impression. In the article, from which the writer thinks the quotation Mr.
was taken,* the full paragraph reads as follows : Suiiivan.

''I may add further that, in reply to my invitation of April 8, 1913,
the contractors who are doing the work, having in mind the method
which was later adopted and which was suggested by myself and one of
their Engineers, bid $6.10 per eu. yd., with a time limit of 42 months
from date of signing contract. Other responsible and supposedly
expert tunnel contractors bid from $8 to $11.25 per cu. yd., with time
limits varying from 42 to 48 months. I do not know what method
these latter contractors proposed to employ, but I always presumed it
would be some modification of the European method."

All contractors had the same information, and the majority of those
who bid sent men on the ground where they could see the character of
the rock, from unbroken rock exposure, for practically the entire dis-
tance of the tunnel, from inspection along the railway, and also over
the bare rock cliffs. These cliffs extended for a height of practically
6 000 ft. above the tunnel, which explains how absurd it would be to
attempt to make borings in order to get any further information than
was apparent from the surface; therefore, the meaning of the phrase
previously quoted is entirely different from that placed on it by Mr.
Lauchli. It simply indicates that the parties having in mind this
method of boring the tunnel had confidence enough iii it to know that
they could build the tunnel 30 or 40% cheaper than by methods pre-
viously used.

Mr. Lauchli further states that his figures of "the cost of driving
this bore, with a bottom heading, would be $5 per cu. yd., exclusive of
contractor's profit." If this was a fact, all the writer can say is, that
Mr. Lauchli's clients must do very well if they can make the proverbial
German 1% profit, that is, of course, providing they get any work.

Mr. Keays is under a misapprehension when he states that "no
heading was driven in the main tunnel, using the pioneer heading to
work from." All the heading in the main tunnel was driven from drifts
cut into that tunnel from the pioneer, and all the material from this
main heading was carried through the pioneer tunnel, either directly
to the outside, or around the shovels to standard-gauge cars back of
where the shovels were working in the main tunnel.

Regarding Mr. Thomson's discussion : This is very interesting,
and the writer is heartily in accord with his idea of paying homage
and doing honor to the remarkable engineers of the past age, and
especially to Major Rogers, whom the writer had the pleasure of seeing
at a meeting of the Society, in Milivaukee, Wis., some 29 years ago.
In this particular detail of the location of the Canadian Pacific Rail-
way, however, Mr. Thomson has a wrong idea. The distance aroimd
by the Columbia River, from Beavermouth to Revelstoke, is 163 miles,

* Engineering News, February 24th, 1916.



492 DISCUSSION" ON TUNNEL CONSTRUCTION METHODS

Mr. 96 miles longer than the line located by Major Rogers, and for the traffic
carried in 1912 and 1913, when the question of double-tracking and
revising the line was being studied, it was seriously proposed to
abandon the Rogers Pass route and build by way of the Columbia
River, as almost enough could be saved in the cost of operation on this
longer line to pay the interest on the construction of the new line, and
a great deal more than the difference in the cost of the two lines, had
the Company been fortunate enough to build around there in the first
place. Nevertheless, the Company is now thankful to Major Rogers,
for, had it originally built the line around by way of the Columbia
River, the writer is sure that it would never have been abandoned for
the present line, which, with the tunnel and heavy business, is more
economical, especially in 'time, than operating the longer distance by
way of the Columbia River. The Company should be especially thank-
ful to Mr. Sammy Sykes, the Locating Engineer, who was responsible
for the "Loops" on the west slope of the Selkirk Mountains, inasmuch
as the original location ran straight down the north bank of the
lllicillewaet, where, to this day, signs of some abandoned construction
work can be seen, but, in order to save money at the expense of dis-
tance, Mr. Sykes put in the "Loops." The result of introducing these
'"Loops" brought the constructed line into the valley of the lllicillewaet,
very close to the West Portal of the Tunnel.

These, the writer thinks, are two instances which illustrate the fact
that it is never very safe to be too sure in a criticism. Here are two
cases which coidd be looked on as blunders, as the increased cost of
operation, in the one case on account of the heavy grades and the large
rise to be overcome and in the other case operating over the longer
distance of line without improvement in grades, with a reasonable
volume of traffic, would be greater than the interest on the money
that was saved in construction, but which really turned out to be a
benefit rather than otherwise.

Mr. Davies asks for information regarding the economics of using
the pioneer tunnel. To quote further from the writer's report of March
13th, 1913, to the Management :

"This method, of course, is only applicable where the rock will
stand without artificial support, at least during the time of construc-
tion. Where the material must be artificially supported, then the top
heading is the surest, and I think, the best way. The progress of the
work by this method, as I said before, depends only on the speed that
the pioneer tunnel can be driven.' If rock is self-supporting, I see no
reason why from 20 to 25 ft. per day could not be made. Placing the
cost of driving the small tunnel at $30 per ft., that is the only part of
the work that would be rushed under high pressure, and the heading
proper can be taken out at least $5 per ft. cheaper than if the work



DISCUSSIOX ON TUNNEL CONSTRUCTION METHODS 493

must be done under pressure, then the bench containing 18 cu. yd. per Mr.
It. (neat section) can, on account of there being no interruptions to Sullivan,
wait for drilling or cleaning up to put in breast holes or knocking
down material in order to get pipes into the heading, at a low estimate,
be taken out 75 cents per cu. yd. cheaper, or $13.50 per ft., which would
make a saving in excavation of tunnel proper of $18.50 per ft., leaving
$11.50 to be taken care of in interest saved account making greater
speed. In my report to you of October 22d, 1912, I estimated an annual
saving of about $226 000, but all my figures were very conservative,
and I took into account only one or two of the larger factors of the
extra expense. Mr. Bogue's more accurate figures show a saving of
over $370 000. However, his estimate for fuel per h.p. hour was 40%
higher than the figure I used, and the price of coal was 17% higher
than the price I assumed. His price is more accurate than the one I
used, but assuming, for the sake of being conservative, that the average
between the two estimates would be approximately correct, that would
mean, say $300 000 per year saving, to say nothing of the interest on
the $3 000 000 or $4 000 0000 that will be invested in construction, from
which we will not be receiving any benefit until the work is completed.
Therefore, if this tunnel can be completed one year sooner by using
this method, the saving thus made will a great deal more than save the
$11.50 additional cost of the pioneer tunnel."

That these estimates were conservative has been proved by the
results, which were better than the estimates. The pioneer tunnel,
from the most careful studies of the information at hand, cost about
$28 per ft. instead of $30, as estimated. There was a great deal larger
difference than 75 cents per cu. yd. between the actual cost of enlarg-
ing the tunnel by this method and the estimated cost of enlarging
without the use of the pioneer tunnel; and another item, not taken
into account in this estimate, was the fact that the pioneer tunnel only
had to be driven less than four-fifths of the total distance. This was an
indeterminate factor at the time these estimates were made, and the
writer purposely omitted referring to it, as it was desired to have the
estimates of this untried method conservative in any reports made to
the Management.

It has been stated by some that this method is not applicable
where there are soft spots in the rock. If the soft rock encountered
does not exceed 50% of the total, the writer is confident that this
method would still prove more economiical than any other which has
yet been tried, for the reason that when the soft places are encountered,
there is plenty of time to stope out the upper part of the arch and
timber it, so that when the steam shovel arrives at those places, there
will be no delay whatever, and. instead of having to stope out the entire
section by hand, as is necessary in the under-heading method, only
about half, or less, of the material in the section requires to be removed
in this manner.



494 DISCUSSION" ON TUNNEL CONSTRUCTION" METHODS

Mr. One word more as to actual costs: To quote further from the

Sullivan, j.^^^^^^ ^^ ^^^^j^ ^3^j^^ -^g-^3 .

"I figure that by this method the pioneer tunnel can be driven for
about $30, the main heading for about $40, and that the bench can be
taken out for about $54, making a total of $124. There will be inci-
dentals; contractors' profit should not amount to over $20 per ft. Of
course, this method of driving the tunnel, working so many drills at
one time, will require a larger plant than if only one heading was
driven, and that at a slower speed than we contemplate."

The expectations of the Eailway Company have been more than
realized, as is proved by the speed and the cost of the work. The cost
of driving this tunnel through rock, including in this price the cost
of driving 19 610 lin. ft. of pioneer tunnel, twelve cross-cuts, each about
40 ft. long, erecting the plant (including freight), the proportionate
cost of building about 5 miles of temporary railway tracks, and other
overhead charges, plus 10% on all expenditures, will amount to a
little less than $5 per cu. yd. for excavation in the tunnel proper.

In conclusion, the writer wishes to say that, in Europe, where it is
understood that drill runners get from 90 cents to $1.25 and laborers
about 75 cents, the method followed in driving the Loetschberg Tunnel
may be both economical and rapid, but all the evidence at hand goes to
show that where one pays from $5 to $6 per day for drill runners and
from $2.50 to $3.50 per day for laborers, the method adopted is by far
the most economical.

Mr. A. C. Dennis,* M. Am. Soc. G. E. (by letter). — The writer is very

grateful to those who have been interested enough to discuss his paper,
and wishes to thank them.

In reply to Hr. Lauchli, in his criticism of the Railway Company
for its lack of geological data for use of bidders, it would appear that,
except for the vicinity of the portals, the Eailway Company could not,
by boring, or other methods, supply information beyond what was
available to the contractors for their inspection of the almost unbroken
rock exposure from Rogers Pass to Bear Creek. The kind of rock and
its pitch are obvious from inspection along the railway, and from the
bare rock cliffs above.

The writer is unable to agree that the bottom heading method of
tunneling is "the only method known to-day, which insures absolute
success, both under favorable and unfavorable conditions." In good
ground, it is obviously an economic question, depending to a large
extent on the cost of labor. For heavy ground, such as that near the
portals of this tunnel, it is believed that the bottom heading system is
unsuitable.

* Vancouver, B. C, Canada.



DISCUSSION ON TUNNEL CONSTRUCTION METHODS 495

There was heavy ground near the center of the mountain, in this Mr.
tunnel, which required timbering. The main heading, from wall-plate ^°°'*-
level up, was excavated to full section by hand, and timbered by seg-
ments from the wall-plate set on rock. When the enlargement and
shovel operations reached this point, no delay or damage to the timber-
ing or bench on which the wall-plate was set was caused by blasting
or mucking the bench. The work on this section was similar to that
of timbering a heading and taking out a bench afterward, except that
the muck going out and the timber, pipe lines, etc., in this case, did
not interfere with other operations, as would have been the case with-
out a "pioneer" heading.

Mr. Lauchli's figures for bids on this work, and his costs for other
tunnels, do not appear to supiJort the bottom heading system as being
the cheaper method, even where cheap labor is available.

Mr. Shailer is quite right that 750 boiler h.p. would appear to be
inadequate. These boilers, of 750 nominal h.p., however, readily pro-
duced 1 000 h.p., by reason of the induced draft. The fuel used was
slightly less than the quantity estimated. The fuel estimate in figuring
the bid was based on 22 lb. of coal per 1 000 cu. ft. of air compressed
to 100 lb. by the gauge.

The compression of air beyond the pressure at which it is to be
used, in order to provide for pipe-line losses, is an economic question
which was given due consideration. It was calculated that the 8-in.
main used was the economic size, and that a larger pipe would not save
by reducing frictional losses to compensate for additional first cost,
less salvage value, plus labor of putting down and removing. The
higher air-pressure requirements noted are the maximum, and only
apply for a short period. For a permanent plant, larger pipe would
have been justified.

It is doubtful whether modern drills will result in much increase
in tunneling speed by the "top heading and bench" system, as sug-
gested by Mr. Keays. The heading drilling may be faster, but the
bench drilling and mucking is usually the limiting feature in progress,
and hammer drills are inefficient in long down-hole drilling. The
writer must disagree with Mr. Keays' statement that the "ventilation
between the working face and portal is unimportant", and also that
the pressure system is preferable to the exhaust. The exhaust method
only requires the mechanical removal of the air from 100 ft. or so of
the heading, but the pressure system requires such removal for
the entire tunnel length, in order to obtain a clear tunnel. The
pressure system tends to mix the fresh air with the smoke and gas,
rather than to drive the smoke out bodily. Wooden pipe, in the ]N"orth-
west at least, solves the ventilating pipe problem, both from an economic
and mechanical standpoint.



496 DISCUSSION ON TUNNEL CONSTRUCTION METHODS

Mr. Mr. Lavis' words of appreciation are very welcome. The writer

regrets that detailed cost figures, which are the real test of any work,
have to be withheld to conform with the contractors' iK)licy in this
respect, but will go so far as to say that, under like conditions, even
if time carried no bonus, he would adopt the pioneer method, unless
there was sufficient time to drive the heading, centrally located, en-
tirely through first, and muck the enlargement from one end only,
and that never again would he use a top heading in hard rock.

The writer regrets that the report referred to by Mr. Thomson, by
the late Virgil G. Bogue, M. Am. Soc. C. E., is not his property, and
he is unable to give the Society the pleasure and instruction which was
his privilege in studying this masterpiece by his old friend and Chief.
Mr. Thomson, as well as many others of the construction days of the
Canadian Pacific Railway, will regret that Major Rogers' name, like
others who helped in the great work, will soon be forgotten on that
railroad. The Rogers Pass Station has been abandoned, and the name
of the Rogers Pass Tunnel has been officially changed to Connaught
Tunnel.

To Mr. Davis, the writer would say that the idea of a pioneer head-
ing originated in the desire to get away from the congestion, smoke,
general confusion, and interference of one operation with another, ob-
served in tunnel driving, and to provide muck in large quantities for
handling by shovel. His work in coal mines, with the air course run
with the main entry, suggested the pioneer as a means to this desired
end. The Connersville blowers were used exclusively for exhausting
from the working faces, and would produce 7 lb. below free air pres-
sure. This provided satisfactory ventilation through 12-in. pipe for
li miles, at which point a second blower was put in, working as a
booster on the same pipe line.

The general wages paid were 40 cents per hour to drill rmmers, and
35 cents per hour to others. The bonus probably averaged 25% in
addition to these rates.

To Mr. Knowles, the writer has to say that the contractor he men-
tions is the one referred to in the paper as having a sub-contract for
labor and explosives in certain headings for a short time, but whose
sub-contract was cancelled on account of unsatisfactory work. Mr.
White also seems to have been misinformed in crediting this former
sub-contractor with the speed made. He and all his organization left
the work a year before Mr. White's visit, at which time only a short
length of heading had been driven in the rock.

In regard to Mr. Dougherty's ix)int, as to whether this tunnel could
not have been built for less cost by other methods, it is difficult to say.
The writer does not think so, but would be much interested in a com-



Dennis.



DISCUSSION ON TUNNEL CONSTRUCTION METHODS 497

parison of costs of other tunnels with those quoted from Mr. Sullivan's Mr
article, due allowance being made for extra cost for long tunnels, and



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