WATER POLLUTION CONTROL RESEARCH SERIES
Deep Tunnels in Hard Rock
U.S. ENVIRONMENTAL PROTECTION AGENCY
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WATER POLLUTION CONTROL RESEARCH SERIES
The Water Pollution Control Research Series describes
the results and progress in the control and abatement
of pollution in our Nation's waters. They provide a
central source of information on the research, develop-
ment, and demonstration activities in the Environmental
Protection Agency, through inhouse research and grants
and contracts with Federal, State, and local agencies,
research institutions, and industrial organizations.
Inquiries pertaining to Water Pollution Control Research
Reports should be directed to the Chief, Publications
Branch, Research Information Division, Research and
Monitoring, Environmental Protection Agency, Washington,
D. C. 20460.
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Proceedings
from
DEEP TUNNELS IN HAED ROCK
A Solution to Combined Sewer Overflow and
Flooding Problems
An Engineering Institute
Presented By
College of Applied Science and Engineering
The University of Wisconsin-Milwaukee
and
University Extension
The University of Wisconsin
Civic Center Campus
November 9-10, 1970
Milwaukee, Wisconsin
For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402 - Price $1.75
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EPA Review Notice
This report has "been reviewed by the Environmental Protection
Agency and approved for publication. Approval does not
signify that the contents necessarily reflect the views and
policies of the Environmental Protection Agency nor does
mention of trade nanes or commercial products constitute
endorsement or recommendation for use.
11
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ABSTRACT
The Proceedings which follow contain the information presented at an
institute held at the Civic Center Campus of the University of Wisconsin
Milwaukee (UWM), on November 9-10? 1970. The program was conducted by
the University Extension under the technical guidance of the College of
Applied Science and Engineering at UWM. Arrangements for the program
and compilation of these Proceedings were completed under the supervision
of Professors Vinton W. Bacon and Paul A. Seaburg.
These proceedings are published by the Office of Research and Monitoring,
Environmental Protection Agency.
111
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CONTENTS
SESSION 1
SECTION 1
SECTION 2
SESSION 2
SECTION 3
SECTION 4
SECTION 5
SESSION 3
SECTION 6
SECTION 7
SECTION 8
PROBLEM DEFINITION AND CURRENT SOLUTIONS
THE FLOODING AND COMBINED SEWER OVERFLOW
PROBLEM IN URBAN METRO AREAS
Vinton W. Bacon
METROPOLITAN SANITARY DISTRICT OF GREATER
CHICAGO EXPERIENCES AND FUTURE PLANS FOR
HARD ROCK TUNNELS
Forrest Neil
MULTIPLE PURPOSE BENEFITS OF DEEP STORAGE
AND TUNNELING
THE ROLE OF STORAGE IN ECONOMICS OF SEWAGE
TREATMENT PLANT DESIGN
William J. Bauer
THE IMPACT OF THE DEEP TUNNEL PLAN ON WATER
RESOURCES IN THE CHICAGO AREA
Victor Koelzer
THE POTENTIAL OF PUMPED STORAGE FOR HYDRO-
ELECTRIC GENERATION IN MULTI-LEVEL DEEP
TUNNEL SYSTEMS
Kenneth E. Sorenson
EXPERIENCES WITH HARD ROCK TUNNELING AND
MECHANICAL MOLES
EUROPEAN DEVELOPMENT AND EXPERIENCE WITH
MECHANICAL MOLES IN HARD ROCK TUNNELING
Pieter Barendsen
EUROPEAN DEVELOPMENT AND EXPERIENCE WITH
MECHANICAL MOLES IN HARD ROCK TUNNELING
Ernst Weber
EXPERIENCE IN EDMONTON CANADA WITH EMPHASIS
ON PNEUMATIC CONVEYANCE OF MUCK
C. G. Chrysanthou
PAGE
33
79
93
113
131
v
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SESSION 4
SECTION 9
SECTION 10
SECTION 11
CONTENTS
GEOLOGY AND STATE-OF-THE-ART PAGE
GEOLOGIC EXPLORATION FOR CHICAGOLAND AND
OTHER DEEP ROCK TUNNELS TO BE CONSTRUCTED
BY MECHANICAL MOLES
George E. Heim, R. W. Mossman, Homer Lawrence l^i
THE CONTRACTORS VIEWPOINT OF THE HARD ROCK
MECHANICAL MOLE - WHAT'S CAUSING DOWNTIME?
WHAT DO THEY WANT?
Victor L. Stevens 175
RAPID EXCAVATION IN HARD ROCK: A STATE-OF-
THE-ART REPORT
William E. Bruce, Roger Worrell 187
VI
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Session 1
PROBLEM DEFINITION AND CURRENT SOLUTIONS
Moderator - W. A. Rosenkranz
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Section 1
THE FLOODING AND COMBINED SEWER OVERFLOW PROBLEM
IN URBAN METRO AREAS
by
Vinton W. Bacon
Professor of Civil Engineering
University of Wisconsin
Milwaukee, Wisconsin 53211
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THE FLOODING AND COMBINED SEWER OVERFLOW
PROBLEM IN URBAN METRO AREAS
What is the magnitude of the combined-sewer problem in the United
States? The most authoritative estimate in the U. S. was made
in 1967 by the American Public Works Association under the sponsor-
ship of the Federal Water Quality Administration of which our
moderator, Mr. William Rosenkranz, is representative.
It is estimated that in the U. S, there are 1,329 jurisdictions,
served in whole or in part by combined sewers, having a total
population of 54 million. Of this projected population, it is
estimated that 36 million are actually served by combined sewers.
Typical are the heavily built-up, central cores in cities such
as Milwaukee, Chicago, Cleveland, Minneapolis-St. Paul,
Washington, D.C., New York, Boston, San Francisco, St. Louis,
and many, many others.
Although the gallonage of sewage overflow is only about 5% of
the total, it is estimated that about 30% of the total pollution
material is overflowed to the waterway. This occurs because
large storm sewers are laid on flat grades, causing low velocity
and settling of much of the sewage solids within the pipes. The
high velocities of storm flows scour up the material, carrying
it to the waterway with the overflow. Thus in magnitude,
tremendous quantities of pollutants are flushed from combined
sewers.
The combined sewer overflow problem can be solved in one of three
ways, or a combination of the three.
First, sewers can be separated, that is, a second sewer can be
constructed in the street. In built-up cities, this would take
years to complete and construction would occur in all of the
combined sewer areas. Politically, it is doubtful if administrations
attempting this solution would survive more than one term. Further,
it is extremely costly. APWA estimates that if all jurisdictions
were to solve the problem through separation that the total ex-
penditure would approximate $30 billion and to make the necessary
changes in and on private property to effect total separation would
increase this total cost to approximately $48 billion. Responses
from many of the municipalities surveyed, especially those with
high population densities, disclose that the possibility of
changing all combined sewers to separate is remote.
Chicago alone estimates that the cost of separation together with
the property connections would cost in excess $4 billion to eliminate
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the effects of the 400 overflow points. Chicago has concluded
not to try separation in the combined area.
Secondly, treatment can be provided at the point of overflow simply
by interception before discharge. Treatment could be by primary
settling, screening, aeration, disinfection, and other means. A
number of worthy demonstration projects for this system are under-
way throughout the U. S., including Milwaukee. Because the overflow
points are usually in built-up areas, one of the difficulties is
the availability of land. This is likely to limit this application.
Having seen sewer separation as politically impractical and too
costly, and having seen limitations of overflow interception and
treatment, both Boston and Chicago, studying independently, developed
an innovative solution. Both cities looked to the underground for
space for the solution, and both separately came to the same con-
clusion: build conveyance tunnels (sewers) and storage caverns in
the underground rock. By building tunnels under the present rivers
in Chicago the overflow at 400 points can be intercepted by vertical
drop shafts, thus allowing only "clean" surface runoff to the
river system. The polluted combined sewer overflow would be stored
during the storm, pumped back to the surface after the storm, and
treated in existing or new plants. Nothing really new, except the
configuration of the component parts. Underground pumping stations,
room-and-pillar mining, circular tunnels mined in hard rock with
mechanical mining machines, and other features have all been used
and proved elsewhere.
This Institute on "Deep Tunnels in Hard Rock - A Solution to Combined
Sewer Overflow and Flooding Problems" is based on 5 major convictions:
1. The combined-sewer overflow problem, with the attendant
flooding problem, in metropolitan urban areas must be
solved if the new and stringent State and Federal water
quality standards are to be met. Secondary, tertiary, and
advanced waste-water treatment of dry-weather flows will
' be a waste of money if the overwhelming raw-waste pollution
of combined-sewer overflows, is not likewise controlled.
2. Of the three apparent solutions (sewer separation, retention
and treatment at the overflow points, and underground
conveyance and storage), the latter provides the cheapest
and most complete solution where rock strata conditions
are favorable.
Retention and treatment at overflow points, such as being
developed and demonstrated here in. Milwaukee, either
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separately or in combination with tunnel and storage
facilities, has great merit, too.
Sewer separation in older, highly developed, and congested
urban areas appears to have little to recommend it.
3. Key to the underground conveyance and storage solution is
rapid and less costly excavation of tunnels in hard rock.
4. Key to such rapid excavation is the mechanical mining
machine for circular or other tunnel configurations.
5. And lastly, the mechanical mining machine has demonstrated,
possibly in a fledgling manner, that it can provide more
rapid excavation and at less cost then other methods
heretofore standard in tunnel construction.
With such convictions, what are the hoped-for goals of this Institute?
First, we want to hear of the successful recent experiences in
Chicago, Western United States, Canada, Europe, and elsewhere.
Through the mere recitation of such experience sharing, we hope
to give impetus to further development and application and
cost reduction.
Secondly, we hope to develop some of the multiple-use aspects
of the deep-tunnel solutions, such as, pumped storage for
hydroelectric storage, storage as a substitute for waste treat-
ment plant capacity, the impact of storage on the water resources
of an area, and the impact of the system on recreation, navigation,
and other beneficial uses.
Third, we hope to assess the future of rapid excavation in hard
rock by mechanical mining through the opinions of machine manu-
facturers, construction contractors, directors of public work,
consultants, educators, and government.
Lastly, we hope to encourage those facing combined sewer and
flooding problems to assess the potential use of tunnels in
their areas, believing that this system is in its infancy and
needful of the creative thinking of many. Boston, as Chicago,
has concluded, after extensive engineering studies that rock
tunnels provide the solution for that metropolitan area.
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Section 2
METROPOLITAN SANITARY DISTRICT OF GREATER CHICAGO
EXPERIENCES AND FUTURE PLANS FOR HARD ROCK TUMELS
by
Forrest Neil
Acting Chief Engineer
Metropolitan Sanitary District of Greater Chicago
Chicago, Illinois 6o6ll
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GENERAL INFORMATION
The Metropolitan Sanitary District of Greater Chicago is a municipal
corporation serving 5,500,000 persons living within a 860-square mile
area in Cook County, Illinois. There are approximately 118
municipalities, including the City of Chicago, and 30 sanitary
districts under its jurisdiction.
Early sewer systems, developed prior to the turn of the century to
serve the City of Chicago and the peripheral suburbs, were combined.
They discharged untreated flows directly into the waterways, which,
in turn, flowed into Lake Michigan - polluting the source of water
supply for Chicago and many of the suburbs.
To protect the water supply, the Metropolitan Sanitary District was
organized in 1889. Drainage in the Chicago River Basin and the
Calumet River Basin was diverted from Lake Michigan (St. Lawrence
River Watershed) into the Des Plaines River (Mississippi Watershed).
This was accomplished by construction of the Sanitary and Ship Canal
in 1911, which served the northern suburbs of Chicago; and the Cal
Sag Channel in 1923, which reversed the Calumet River System. Three
control structures prevent the river and canal system from flowing
into the lake and permit the entrance of lake water to the system.
The canal system, in addition to providing pollution and flood control,
is a major shipping artery for bulk commodities. (Fig. 1)
At one time up to 9,000 cfs were diverted from Lake Michigan into the
canal system to dilute the sewage. In 1925 several states instituted
a suit against the State of Illinois and the Metropolitan Sanitary
District to limit diversion. It was heard by Special Master Hughes
for the Supreme Court of the United States. The court issued a
decree in 1930. The decree forces the Metropolitan Sanitary District
to increase its program of construction of plants and intercepting
sewers 'so that it would be able to reduce diversion to 1,500 cfs by
1940 for all purposes except water supply.
On June 30, 1967, the State of Illinois adopted water quality
standards. These were subsequently approved by the Federal Government.
These standards require that canals presently used for industrial
cooling water supply, sMpping and waste assimilation be upgraded to
where they car, be used for water supply and recreation.
The B.O.D., suspended solids, and other parameters in municipal
treatment plant effluent, industrial waste discharges and combined
sewer overflows exceed the assimilation capacity of the canal and
river system. None of the major waterways meet the standards.
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The adoption of the standards and limitation of diversion waters by
decree have forced the Metropolitan Sanitary District to include
tertiary treatment at its plants and an equivalent of separation of
sewers in combined sewer areas in the future program. The diversion
will be further reduced, increasing the severity of the problem, as
other communities and sanitary districts request an additional share
of the 3,200 cfs for water supply and diversion of sewage effluent
from the lake.
The Metropolitan Sanitary District has proposed a $2 billion-dollar
ten-year program to meet the water quality standards and permit higher
uses of the waterways.
COMBINED SEWER PROBLEM
In the City of Chicago and older suburbs, there are over 300 square
miles (Fig. 2) served by combined sewers. These areas are almost fully
developed - having only about 12% vacant property. Many industries
using large quantities of water are located in these areas.
Most of the Suburban combined sewer systems discharge their storm
overflow to the local streams. These streams flow through Forest
Preserves or other recreational areas. Swimming or wading cannot be
permitted due to the polluted condition. Fishing is limited to a
very few areas.
The greatest number of the 400 overflow points (Fig. 3) from combined
sewers discharge directly to the canal system. Use of canal water is
generally restricted to cooling water due to the poor water quality.
The cost of separation of sewers would be over $4 billion-dollars.
Disruption of the community and loss of business during the construction
would add considerable expense to this figure.
Based on present knowledge of storm runoff from urban areas it is
doubtful if separation would sufficiently improve the quality of the
waterways to meet standards.
FLOOD CONTROL PROBLEM
The Metropolitan Sanitary District has the responsibility of providing
outlet capacity for drainage from the Greater Chicago area. The
canal system, whicii discharges through a control structure and power
house into the Des Plaines River at Lockport, and the upper portion
of the Des Plaines River and its tributaries are the main stormwater
outlets.
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Rapid urbanization of tha area is increasing runoff and peak flows in
the waterways. This, is Illustrated by the fact that the Metropolitan
Sanitary District has had to permit the canal system to flow to the
lake on eight occasions during severe storms in the last ten years to
prevent flooding.
No major improvements to increase the outlet capacity have been made
to the Sanitary and Ship Canal or the Des Plaines River since their
original construction. Additional capacity in the canal and river
system must be provided by deepening and widening, or stormwaters must
be detained and gradually released after the peak of the storm.
Failure to do this will cause storm flows to be released into Lake
Michigan with increasing frequency - a violation of the standards and
our ordinances.
Retention of storm flows in surface reservoirs has been a standard
flood control practice for many years. The Metropolitan Sanitary
District has constructed, has participated in the construction of and
has future plans for approximately 15 surface reservoirs on the
smaller streams. These are primarily in the separate sewered areas.
In the combined sewer area, the flat topography, development of the
area, and cost of land limit the number of reservoir sites, therefore,
investigation of the potential of subsurface storage becomes desirable.
This would include rock tunnels and storage areas.
EQUIVALENT OF SEWER SEPARATION - DEEP TUNNEL PLAN (Fig. 4)
It must be emphasized to meet water quality standards we must
collect and treat overflows from the combined sewer area. Conveyance
tunnels and storage reservoirs will be required.
Basically, the plan provides for intercepting the combined sewer over-
flow ahead of the outfall, diverting it into conveyance tunnels and
storing the flow in underground and surface reservoirs. It would then
be treated at existing and new plants before discharge to the waterway.
Several plans for equivalent of sewer separation have been reviewed.
The two basic plans - which are being merged at the present time -
are the Deep Tunnel Plan proposed by the Metropolitan Sanitary
District, and a composite plan proposed by the City of Chicago (Fig. 5).
It has been agreed among engineers in these agencies that underground
rock tunnels, combined with storage underground and on the surface, is
the most feasible method. Both plans have these features. The City
of Chicago has been engaged by the Metropolitan Sanitary District to
develop a plan for 11 miles along the North Branch of the Chicago River
and the North Shore Channel and prepare plans and specifications for
the initial contract. The work in this area can be designed to be
compatible with variable plans which may be decided upon downstream.
The first tunnels will be constructed within the Niagaran rock formation,
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Tunnels paralleling the waterways are proposed which will intercept
the overflows. The tunnels will provide storage as well as transport.
In addition, large storage reservoirs on the surface and in the rock
are proposed in the vicinity of our major sewage treatment works.
These storage reservoirs will permit combined sewage to be treated
after the storm using peaking capabilities of the plants.
The three rock tunnels presently under construction can be incorporated
into the projects. Their point of discharge would be to a conveyance
tunnel below them which would greatly increase the discharge capacity
due to the additional head available. The construction of these projects
is proving the feasibility of using rock moles for tunneling in lime-
stone.
RELIEF INTERCEPTING SEWERS (Fig. 6)
Due to the rapid expansion of the Metropolitan Sanitary District in
area, population, residential, commerical and industrial development
in the last 15 years, relief sewers are required to convey the waste
to our treatment plants. The District doubled in size in 1956. To
provide immediate service, future capacity in the then existing
intercepting sewers was committed to serving the newly annexed areas.
Relief sewers, at a projected cost of $100,000,000 are planned through-
out the Metropolitan Sanitary District to provide service when the
area is fully developed.
The Metropolitan Sanitary District is presently proposing using the
same deep or underflow tunnels, which will convey the combined sewage,
as relief sewers to take quantities in excess of the dry weather flow
capacity of the existing interceptors. This will eliminate the need
of a parallel relief sewer at a higher level to convey the flows to
the sewage treatment plants. The tunnels and storage areas will also
enable the Metropolitan Sanitary District to reduce or practically
eliminate the hourly fluctuation in sewage flows at the plants. By
having an even flow through the plant, a better effluent can be
maintained, as one of the variables of plant operations is controlled.
Mining storage reservoirs, using multiple headings, is believed to be
economical. The underground quarrying of limestone has been done else-
where in the nation. Cost estimates which we are presently reviewing
indicate less than the $5/yard we have in our initial studies. The
industry already has developed the equipment required.
TREATMENT FACILITIES
As we will be mining tunnels and storage areas in the rock under our
plants, the advantages and disadvantages of constructing treatment
facilities underground are being investigated. If the areas for
treatment facilities are mined at the same time as the tunnels, the
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cost would be reduced due to the large cost of setting up a mining
operation.
There are advantages, in the subsurface which include:
1, Having limited space at the existing plant sites, additional
land will be needed to meet the requirement of tertiary treatment
and treating combined sewer overflow. Underground construction
should minimize the additional land required. Land in the vicinity
of the existing plants is very expensive and largely developed.
2. Tests indicate oxygen transfer is speeded up under pressure. By
using the available head in a siphon arrangement, it may be possible
to cut aeration time thereby reducing the size of facility required
and cost of mining below ground.
As we presently believe the only practical method of removing ammonia
is to nitrify, we are considering additional batteries of aeration and
final tanks to provide two-stage aeration at our major plants. This
requires large sites.
We have constructed a small pressurized activated sludge plant.
Experiments with this unit, as well as lab experiments, will determine
the feasibility of this concept.
PRESENT TUNNELING EXPERIENCES
Tunneling construction methods for water conduits, subways and sewers
have been developed in the Chicago area over a period of many years.
Mining machines are now extensively used in the clays and granular
materials. Rock moles are presently being used on three major contracts
in the Chicago area.- These contracts are as follows:
...Lawrence Avenue Tunnel, a 13'8" diameter bore, for the City of
Chicago, being constructed by S. A. Healy at a cost of $10,792,.094.
(Fig. 7)
...Calumet Intercepting Sewer 18E, Extension A, a 16'10" diameter bore,
being constructed by S&M Constructors for the Metropolitan Sanitary
District, at a cost of $6,954,675. The cost per cubic yard
excavation, unlined, is $33.50. (Fig. 8)
...Southwest Intercepting Sewer 13A, a 13'10" diameter bore, being
constructed fay S. A. Healy and Kenny Construction Companies for the
Metropolitan Sanitary District, at a cost of $6,210,736. The cost
per cubic yard excavation, unlined, is $50.09. (Fig. 9)
These projects are in the Niagaran limestone formation and are
located approximately 200 ft. below the surface. They are proving the
effectiveness of the rock moles in the Chicago region. The rock is
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structurally sound, which eliminates the need for a conventional con-
crete lining for structural support. The contractor is required to
grout and stop any leaks which occur. After completion of the mining,
the tunnels will be inspected to determine what surface treatment, if
any, will be required.
A Jarva machine was used on the Calumet 18E Ext. A sewer. The mining
is nearly complete. The average progress per hour was 4.9 ft, A
Robbins mining machine was used on the Southwest ISA Contract. The
mining is presently completed. (Fig. #10}
Infiltration enters the project from the shafts, line holes, some of the
horizontal bedding planes and vertical faults. No grouting was per-
formed during construction on the Calumet 18E Ext. A job. Portions of
the Southwest ISA project were grouted before and during the mining
operation. After the mining of these tunnels, additional grouting is
required.
These tunnels are designed as siphons which will discharge to the water-
way during all but the smaller storms. They will be de-watered by a
pumping station after the storm into an intercepting sewer, which will
convey the flow to a major sewage treatment plant. The storage in the
system is used in this manner to reduce the pollutants discharged to the
stream.
In our area experience with rock moles is limited to about 3 years. Im-
provements are continually being made. It is expected that the next
generation of machines will greatly,improve operations and procedures.
GEOLOGY OF REGION
The upper strata consist mostly of tills, lacustrine clays with some
stratified deposits and sand dunes (Fig. #11). The Niagaran and Galena
Platteville limestone formations underlie the urban area - separated by
a shale formation - the Niagaran being approximately 0 to 300 ft, below
the surface. To date, except for quarrying from the surface in the
Niagaran and construction of water tunnels and a small number of wells,
little use has been made of the limestone formations.
In the last few years, over $1,925,000 have been expended on investiga-
tions which included seismic, drill holes and rock cores, and logging
existing and new wells. Additional information will be obtained as new
tunnel alignments are decided upon. The data have provided substantial
information on the rock strata.
SUMMARY
Space is at a premium in metropolitan areas. Surface reservior sites
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for flood and pollution control are limited in number and costly. Where
subsurface projects can be constructed at prices competitive vdth more
conventional surface solutions and having additional benefits, they
should be carefully evaluated.
Underground construction provides; advantages that should be considered
in urban areas.
1. It greatly reduces the disruption of an urban community. Utilities
are generally not affected as they are with open-cut work. The
costs of moving utilities are generally assumed by the utility com-
pany. This is a cost which is not reflected when open-cut and tun-
neling estimates are compared. There is little inconvenience to
residents compared with open-cut work. The construction does not
interfere with the operation of existing commercial and industrial
establishments.
2. As a part of a system, the deep tunnel can provide an equivalent of
sewer separation. This will improve water quality and enable the
area to meet established water quality criteria. The cost should be
less than 25% of the cost of sewer separation. Due to the pollution
in storm runoff from urban areas, sewer separation would not suffi-
ciently improve the quality in the waterways to meet the established
standards. The system could be enlarged to handle polluted runoff
from separate sewer areas.
3. Providing an outlet far below the existing local sewer systems will
improve their performance and permit much more flexibility and
economy in the design of relief systems in the local communities.
4. Collecting, storing and treating combined sewage before releasing
to the canal will reduce the amount of diversion water required to
meet the standards. This is of great importance as the demand for
lake water in Northeastern Illinois increases.
5. The large volumes of underground storage provide a means of reducing
peak flows in the channel system - eliminating the need for dis-
charge of contaminated water to Lake Michigan in severe storms as
has been required in the past. It should reduce or eliminate the
need for major widening and deepening of the waterways.
6. The mined rock from many of these projects can be stored in existing
quarries for future commercial sale, used to create additional park
land or in the lake airport which is under consideration, used to
create a recreational mountain in this flat region, etc. Many of
these uses provide a benefit that can be measured in dollars - re-
ducing the cost of the projects.
7. Surface and underground reserviors can permit regulation of flows
to the treatment plants - greatly Improving their operational effi-
ciencies.
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8. Underground construction can permit greater expansion of plant
facilities at existing sites.
9 Improvements in design in tunneling equipment are going to further
reduce the price of excavation.
QUESTION: How will solids be handled in the tunnels or room and pillar
type storage?
NEIL: We felt that as a part of the design of the deep tunnel sys-
tem we would need some settling tanks for the removal of
solids. We do not have the complete answer as yet, but we
feel it would be easier to collect solids prior to entering
the tunnel. The requirements for aeration and the length
of holding time in the underground storage areas are being
studied.
QUESTION: What are the differences between the underflow storage plan,
the deep tunnel plan and the Chicago drainage plan?
NEIL: The basic differences between the deep tunnel and underflow
plans is the amount of storage. The deep tunnel plan has
about 60,000 acre feet to collect all overflow, the under-
flow plan has about 20,000 acre feet. The drainage plan
involves treatment at 400 overflow points and increasing
the capacity of the canal system.
QUESTION: How many miles of tunnels do you envision in the final sys-
tem and how many are now under design for the next phase?
NEIL: Currently eleven miles are planned. The total tunnel system
for Chicago only would be from 40 to 50 miles. Including
the suburbs the system would be in the hundreds of miles.
QUESTION: What techniques will be used for constructing the shafts?
NEIL: A conventional mining technique has been used. Future con-
tracts may work, either from the top down or the bottom up;
this will be left as an option.
ROSENKRANZ: The hydraulics of the down shafts are critical and are being
studied. The FWQA has initiated some work at the University
of Minnesota.
QUESTION: What are the legal implications of tunneling under private
property?
NEIL:
We try to stay under public streets, otherwise we obtain
an easement with the owner.
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CHANNEL
'SYSTEM
Fig. 1
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<
] V~M. S. D. BOUNDARY
I—1
AREA OF COMBINED SEWERS
Fig. 2
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Sanitary District Sounoary
••v 5
^•>-|L^3 CHICAGO
RIVER
JM
Th» Metropolitan Sanitary District of Creator Chicago
§anE2 OVERFLOWS
20
oniuow TO ium ci
ig. 3
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TUES3GSSEL
FOR
FLAW
M.S.D. INTERCEPTOR
Discharge
Conduit
700
PUMP & GENERATOR
NATION
Drop
Shaft
UNO E R F L O VV TUNNEL
N i a g a r a n
ROCIC STrJAYUi'v
TUNNEL
ROOM & PILLAR STOP,AGE
Oolcnc) - Plcitfovlllo
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WILUIETTE
LAKE
MICHIGAN
CHICAGO
RIVfl
CONVEYANCE
TUNNEL:
COMBINED
SEWER
AREA
CHICAGO
WESTERN |
SPRINGS .-•
STORAGE
CONVEYANCE
TUNNEL
HARVEY ! -A
D- 1 rj 7 r i A r
^i L« ij t. \~s » w L \j Li ui - *j ^ - - - - - ^-^ - ^
^3* ^ j^\ /t^^ *"^s ^\ ^" r~^\ ^^ ^^^ ^ 9 '
.• _j £.. _ _j IP y L L .
. -
22
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THE METROPOLITAN SANITARY\ D5STR:c\ OF\JREATER CHICAGO
6HUNOY CO
LEGEND
HTREATMENT PLANTS
O PUMPING STATIONS
"^INTERCEPTING SEWERS
Fig. 6
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ROCK TOENEL SUI-aSVRIBS
LAWRENCE A VS. SEEER SYSTEM
CONTRACT NO. 1
Length of Tunnel:
In Lawrence Avenue.
In Lawrence Avenue
In Harding Avenue
* 9,126 feet of IS'S^s" x 19'5"
12,670 feet of 12 foot dia.
3,968 feet of 12 foot dia.
25,764 feet
*6,760 feet mined by machine to
13'8" and enlarged by drill and
blast method and 2,366 feet full
face drill and blast with finishec
section of 8" liner to dimensions
of 15'6*s" x 19'5"
Depth below Ground
245 feet max, 220 feet rain
Slope of Sewer
2.5 per 1000
O.S. Diameter specified:(Mined by Machine):
In Lawrence Ave.(1st 9,126) 18'4" dia.
In Lawrence Avo.(last 12,670') 13*4? dia.
In Harding Avo.(3,968*) 13*4" dia.
O.S. Diameter Actual:
In Lawrence Ave.(1st 9,126')
In Lawrence Ave.(2nd 12,670')
In Harding Ave.
16'10*j" x 20'9" D&B or enlarged
from machine bore of 13*8"
13'9" dia.
13'9" dia.
I.S. Diamater:
In Lawrence Ave. (1st 9,126')
In Lawrence Ave. (2nd 12,670')
In Harding Ave. (3,968')
Tail Tunnel
Shaft
Contract Costs (Bid) t
1. Shaft
2. 12 foot dia. Tunnel
17 foot dia. Tunnel
3. 12 foot dia. Lining
17 foot dia. Lining
4. Rock Bolts
5. Wire Mesh ^^ 2
15'6>5" x 19'5M (lined)
12 '0" dia. (if lined)
12 '0" dia. (if lined)
61 feet
27 feet dia. and 256 feet deep
600,000
4,658,640
3,732,534
993,280
730,080
67,500
i 5,000
$10,792,094
Fig. 7
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ROCK TUNNEL SUMMARIES
LAWRENCE AVENUE SEWER SYSTEM
CONTRACT NUMBER 1
Increased Storage (without cone. 31% increase in Volume
lining in the 12' dia. sections)
In Lawrence Ave. (west of Sta. 91+50) 16,610 cubic yards
In Harding Ave. 5.202 cubic yards
TOTAL 21,812 cubic yards
Award Date
November 1, 1967
Term of Contract
1,095 days
Specified date of completion
November 5, 1970
Normal Shifts
2k Hours Monday through Saturday
Total Progress to date:
Lawrence Avenue:
Machined mined (13'-8")
Drill and Blast Enlargement
In Harding Avenue (13'9")
13,094 feet
9,126 feet 9/30/70
9,126 feet 9/30/70
3,968 feet 9/30/70
Progress Max. Week
'Progress Max. Day
Maximum Penetration ft./hr.
Comp. Strength Rock p.s.J.
347 feet 2
92 feet (2
Shifts
Shifts)
8.7 maximum
11,400 to
29,600
Mining Machine:
Manufactured by
. Thrust of Machine
Drive of Machine
Operation Voltage
; Make of Bits
Number of Cutters
Diameter of Cutterhead:
; Machine Number 1
Machine Number 2
Lawrence Mfg. Company
1,300,000 Ib. (Max.). 850,000 Ib. oper.
5-125 hp. motors
480 Volts
Lawrence Mfg. Company
29 Disc-Type with carbide inserts
J3'-8" dia. in Lawrence Avenue
131.911 dia. in Harding and Lawrence
Length of Machine:
-------
ROCK TUNNEL SUMMARIES
LAW3ENCE AVENUE SEWER SYSTEM
CONTRACT NUMBER 1
Assembly
Drawbar
Powar Train
Auxiliary Power.Train
TOTAL
Tunnel Power Lino
4,160 Volts
Conveyor System Manufacturer
Lawrence Mfg. Co. with a Goodyear
Belt 2k" wide by 8V long
•Muck Cars
Length of Train
Track Gauge
Locomotives
6 Cubic Yards
9 Cars
36"
10 Ton, Plymouth
Diesel, 86 hp.
Venti1at ion
28" Vent Line
2-^*0 hp Vent fans made' by the
Joy-Axivane Co.
14,000 CFM each.
One 15 hp. fan at street level
to prevent any line back pressures.
Contractor
J. McHugh Construction Co.
S. A. Healy Co., and Kenny Con-
struction Co. (a joint venture)
'esident Engineer
John Redmore
-------
93KD
—
957H
CALUflET IDS. EJJY.A
€0::T^G 6S-211-2S
10,500 Ft. !6'-10" Dia.
$5,764,200.
$6
1
n:::j PAP.::
M
>
<
997H
si
i - >
-
:
f'~
%\
\ £
i ~' I
i -M.
i
CT?' |-
ri
^ '
ST.
if
i
ST.
ST.
.-f-_i-ffl!tmJ ^—-
57.
PtJESGNT POPULATION 44,000
•2 II il
i •>] AP.2A SZKVED 4,500 ACRES
" !! *l
I i D^IGr-J POPULATION 04,000 | ST>
i
i ^--. ~_-j
tS
EXISTi.XG r.i.S.D. SEWERS
TO CALU.V.2T S.T.W.
TOTAL COST $9,206,200.8
SHAFTS
pur.:pir^G STATION
$3,540,000. 69-215-2S
7 jj ST, THE METROPOLITAN SANSTARY DIST
=;' I OF GXEATE2 CHICAGO
RiCT
DIPART.V.SNT
OCT., 1970
Fig. 8
-------
SOUTHWEST SIDE 13-A
3.4 Hiles of 13'-10" Dia.
$5,350,723.
EXISTING VILLAGE SEWER
DES PLAIWEG
SHAFTS £
PUHPIHG STATIC:]
$3,540,000. 68-136-2S
BROOKFIELD
niYONSm
LAGRANGEB
'••"///y//////////'
AREA SERVED
31,900 ACnES
SOUTHWEST S3s)2 13A
SAHITARY SEWER
15 Inch Diauctcr
24 Inch Diomefcr
$1,189,560. 68-13'
i20,000 Existing Populotion ^
34,100 Projected Population
AiC COOK
55'th
FOTAL COST $10,000,203
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ROCK TUNNEL SUMMARIES
Lenqth of tunnel
Depth below qround
Slope of Sewer
O.S. Diameter spec If Fed
O.S. Diameter Actual
1 . S. Diameter (if 1 ined)
Tai 1 Tunnel
Shaft
Contract Costs
1. Shaft
2. Tunnel
3. Lining
4. Bulkhead
TOTAL
Increased Storage
(without Cone, lininq)
Award Date
Term of Contract
Specified date of completi
Normal Shifts
Proqress to date
Progress Max. Week
oqress Max. Day
Lawndale Avenue 5-47 St.
SWIS 13A
17.553 feet
235 Max. 201 Min.
2.1 per 1000
13' - 4"
13' - 10"
12' - 0"
250 feet
30' and 28'x206' deep
Bid Revised
850,000 850,000
4,567,206 4,503,723.60*
793,530 0
included above
6,210,736 5,350,723.60*
*includes credit for rock
material and refund on
Elec. Agreement
($3.60/1 in. ft. credit
on rock) .
36% increase in volume
24.000 Cubic Yards
June 6. 1968
930 davs
ion January 5. 1971
24 hrs. Mon. through
Friday
17.553 (9/24/70)
591 feet
1 44 feet
127th & Crawford Ave.
Calumet IBE-Ext. A
18,320 feet
223 Max. 216 Min.
1 .5 per 1000
16' - 4"
16' - 10"
15' - 0"
260 feet
29' and 27'x223c deep
Bid Revised
1,000,000 1,000,000
4,763,200 4,763,200
1,190,476 0
1,000 1,000
6,954,675 5,764,200
26% increase in volume
31 .000 Cubic Yards
May 17. 1968
933 davs
December 16, 1970
24 hors Mon. through -
Saturday
16.018 (9/29/70)
607 feet
129 feet
29
Fig. 10.
-------
Lawndale Avenue & 47th St.
SWIS 13A
127th & Crawford Ave."
Calumet l8E-Ext. A
Maximum Penetration ft./hr. 5.5 avq. 8.2 maximum
7.6 maximum
Comp. Strength Rock psi.
15,000 to 24,900
23.500 to 39.000
'Mining Machine
Manufactured by
Thrust of Machine
Drive of Machine
Operation Voltage
Make of Bits
Number of Cutters
Length of Machine
Pi a. of Cutterhead
James S. Robbins &
Assoc. Inc.
890,000 Ib. (max.)
6-100 hp motors
460 Volts
James S. Robbins &
Assoc.
27 Disc-Type plus
Tri-Cone
37 feet
13 feet 10 inches
Jarva Inc.
2,200,000 Ib. (max.)
8-125 hp motors
480 Volts
Reed Dri11 ing Tools
54 Reed Type Q.K.C.
35 feet
16 feet 10 inches
Conveyor System
manufactured by
Moran Engineering
Co. 96' bridge con-
veyor (20" widebelt)
to 132' (18" wide
belt) car loader
Card Corporation
260 feet conveyor
supporting a 30" belt
Muck Cars
Length of Train
Track Gauge
Locomot i ves
4.4 Cubic Yards
10 cars
24"
10 Ton, Plymouth
Diesel. 70 hp
10 cubic Yards
10 cars
36"
15 Ton, Pl-ymouth
Diesel. 160 hp
Ventilation
30" Vent line
2-100 hp Vent fans
@12.000 CFM each
36" Vent line
Joy-Axivane fans
31.000 CFM max
Contractor
S. A. Healy Company
and Kenny Construction
Co. ( a Joint venture)
S.&M Contractors
Inc.
Resident Engineer
George A. Taylor
Thomas P. Vitulli
30
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Session 2
MULTIPLE PURPOSE BENEFITS OF DEEP STORAGE AND TUNNELING
Moderator - G. Rohlich
31
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Section 3
THE ROLE OF STORAGE IN ECONOMICS OF
SEWAGE TREATMENT PLANT DESIGN
by
William J. Bauer
President
Bauer Engineering, Inc.
20 North Wacker Drive
Chicago, Illinois 60606
33
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THE ROLE OF STORAGE IN THE ECONOMICS Op
SEWAGE TREATMENT PLANT DESIGN
I should like to speak about a very- simple concept, discuss some of the
ramifications of the concept, and then attempt to answer any questions
you may have. The basic concept is to secure a higher load factor or
higher per cent utilization of treatment plant facilities. It has its
parallel in the pumped storage idea applied to an electric utility.
The variation in electric power demand is quite marked, so of course is
the demand for treatment plant capacity. Now the significance of this
variation is becoming greater with time, because the cost of treatment—
that is, the number of dollars it takes to buy a million gallons per day
capacity—is going up. We require more and more of these treatment
plants, and we require less and less pollution to be discharged from
them. So, if there's any way of making this expensive plant work harder,
it seems that we should take a look at it. Obviously, the way to do
this is with storage, and the economic choice involves the relative
costs of water storage and treatment capacity. I shall proceed first
with some of the graphics that I have, then I shall present some of the
results of a study we made on this matter.
FIG. 1
These two curves illustrate the point that I was making about the rela-
tive costs of storage and treatment capacity. Here you see one curve
labelled "higher flow rate" and the other "lower flow rate," which would
be associated with a higher load factor. This is merely a schematic
representation of the fact that with primary treatment only the differ-
ence in cost was small so that it was not as important to regulate flow
through the plant. As we begin to spend more money in reducing the
permissible pollution the spread between these curves becomes greater.
There is getting to be a much larger cost differential as we are re-
quiring more and more advanced forms of treatment.
FIG. 2
The scale on the left is the BOD discharged in the effluent from the
Southwest Sewage Treatment Plant of the Metropolitan Sanitary District
of Greater Chicago. This diagram pertains to a one-year study made by
the Federal Water Pollution Control Administration. The scale at the
bottom is per cent of time. Three curves are shown: The lower one
is for typical average flows. Each one of these curves was plotted with
the aid of daily laboratory data taken from the analysis of the effluent
of the treatment plant. If you read the chart at a certain "per cent
of time" on a vertical line, you will find that a higher flow going
through the plant has, in general, a higher BOD in the effluent. So, at
any vertical line we wish to examine, we find that superior treatment is
-------
achieved with the lower flow rate, as one would expect.
FIG, 3
Here is an actual plot of data taken from a treatment plant in the sub-
urban Chicago area; you can see quite a variation with pronounced peaks
and valleys, A very sharp peak corresponds to some rain. I have drawn
two lines: one line represents the dry weather flow, and the other
represents- 1.33 times the dry weather flow. We were examining in this
study, on the basis of the actual historical variation in these flows,
what volume of storage was required in order to limit the flow rate
through the treatment plant to this flow of 1.33 times the dry weather
flow. Some sewers have many direct connections which allow storm
water to get into them, producing a very wide ranging fluctuation.
FIG. 4
This plot is taken from still another example in the Chicago suburban
area. It is based on historical variation of flows in a two-year period
at Bloom Township Sanitary District. Plotted vertically is the treat-
ment capacity in millions of gallons per day, and across the bottom
the storage that would be required to not exceed that flow capacity.
This is of course the end result of the type of statistical study I
described when discussing the preceding diagram. We analyzed two dif-
ferent yea r^: One curve represents the relationship for the '67 flows,
and the upper one represents the '68 flows. The trend line shows that
we could achieve the same end result with the capacity of 15 million
gallons per day if we could store 7 million gallons as we could with
a 20 mgd plant with no storage at all. The slope of this curve is
obviously very important and it is something that depends on the statis-
tical variation in the particular flow system. Now, if this curve is
steep it is obvious that a great deal is gained by storage; conversely,
if it is flat, one does not have very much incentive to store.
FIG. 5
These curves were developed for the Deep Tunnel Plan study for the
Metropolitan Sanitary District of Greater Chicago. Again, you see on
this side a measure of the amount of pollution (in this case it is the
volume of spill). Running across the bottom again is storage. As we
increase the storage of the system, we are able to reduce the frequency
of spill so that the total quantity of the spill is also reduced. We
have a family of curves here, each for a particular sustained rate of
flow through the treatment plant. The distance between two curves at
any particular level is the incremental storage required to achieve
the equivalent treatment in terms of the same volume of water spilled
-------
Into the waterway. The variation here shows, for instance, that storage
would permit us to reduce the treatment capacity from 1500 to 375 mgd.
That means that the treatment capacity ould be reduced to 1/4 of what
otherwise would be required in order to handle a given situation. I
should like to contrast this diagram with the preceding one because the
previous one was presumed to be a separate sewer system—one not sup-
posed to have any storm water connections to it—and this one is a corn-_
bined system. You notice a great deal more benefit from using storage
in connection with the combined system. The effect of storage on treat-
ment plant capacity depends: a great deal on whether the system is sep-
arate or combined.
FIG. 6
Now there is also a question of the effect of storage on the cost of
transporting the water. If the collection system is rather long, one
achieves a relatively greater economic advantage from a high per cent
utilization of that transportation system. This diagram is a schematic
showing (in dotted lines) a flow-regulating storage system at the head
of a collector system, then at the treatment plant itself an additional
storage to perform the function of even further regulating the flows
through the treatment plant. The lower diagram illustrates the typical
variation during a day for domestic flows giving one way of evaluating,
on a daily basis, the effect of storage on regulating flow through the
plant.
I should like to cite some figures on the relative costs of these two
systems: First of all, with regard to the cost of storage—this can
vary widely, depending upon the facilities that are provided. In the
Deep Tunnel Plan studies of the Metropolitan Sanitary District of Greater
Chicago the bulk storage which was proposed in the mined portions of the
plant carried a price tag of about $5 per cubic yard. That did not in-
clude the cost of handling solids, and the cost of aerating the flows
that would be stored there temporarily. If you divided the $5 (call" it
$5.40) by 27 cubic feet in a cubic yard, the result is about $.20 per
cubic foot of space. By the time one adds facilities for handling solids,
the cost will increase to perhaps $1, or conceivably, $1.50 per cubic
foot of storage. On the other hand, the cost of concrete boxes with lids
at ground levels, scraper mechanisms for handling solids, plus some
aeration facilities would probably be in the vicinity of $5 a cubic foot.
The range we would expect to talk about is in the neighborhood of $1.50
to $5.00 per cubic foot, or about $40 to $135 per cubic yard, or $64,000
per acre foot, or more. Most of the cost in the case of the underground
system is tied up in the facilities for handling solids and aerating.
I should like to give you some analyses here of relative costs of a 30
million gallon per day plant, with and without storage. I have used one
unit cost for the treatment facilities themselves and that was $400,000
per mgd capacity. We also assume that with no storage at all, we could
provide two times dry weather flow for the basic treatment plant capacity,
-------
meaning that it would have a capacity of 60 million gallons per day.
Now the 60 million gpd multiplied by the $400,000 per million gallons
gives $24 million for the treatment plant capacity without storage.
I recognize that quite commonly activated sludge plants are designed
for little more than 1.0 times dry weather flow as far as the system
of aeration, the aeration chambers, and the biological process are
concerned, but, that they are designed for a hydraulic capacity of
2 or 2-1/2 times the dry weather flow. This procedure is based on an
acceptance of a reduced level of treatment during the time in which
the plant is overloaded. Now, one of trie basic assumptions I am making
in these analyses is that this kind of operation is not going to be
permissible for very much longer, because it is in the same category
as dumping or bypassing when the plant is down. So, in assigning the
unit costs, I have said that a plant averaging 30 million gpd could be
designed to perform well at a peak rate of 60. That is the background
for the $24 million figure.
Then I examined a unit cost of $45,000 per acre foot of storage capacity
and added varying amounts of storage capacity and calculated the cor-
responding reduction in treatment capacity. With 13 million gallons
of storage capacity, the plant cost was reduced by $4 million. The
cost of that storage was $1.8 million, so that there was a net saving
of $2.2 million. Going still further, reducing the treatment plant
capacity to the level corresponding to 26 million gallons of storage,
the treatment plant was estimated to be $16 million, and the storage
about $3.6 million, or a total of $19.6 million compared to the $24
million for the plant without any storage. These figures, of course,
depend entirely on the statistical relationship between the volume of
storage and the corresponding possible reduction in treatment plant
capacity. Obviously, it also depends upon the unit cost of storage.
If the storage is underground (as would be a convenient location in a
crowded urban area like Chicago) one would have an added cost of pump-
ing water back up. An analyses of the amount of that storm water that
would be passed to a lower storage zone, then pumped back up to the
surface during a typical year in Chicago, resulted in about 14% ratio
of storm water volume to total water volume.
There are some advantages to providing this storage other than possibly
an economic one. If the rate of flow through the plant is capable of
being controlled, the processes can be adjusted to a better degree so
that the performance is improved. The flow into the receiving stream
is better regulated, so that there is a higher sustained flow and fewer
high peaks. In the event there is a mechanical breakdown in the plant,
the storage it provides is an optional one to dump the water which
otherwise might be directly bypassed into the stream. We did not make
a statistical study to obtain a correlation between the occurrence of
these natural breakdowns and the occurrence of the storms; but, I think
it is evident that one would not expect these events to happen at the
same time, therefore, the storage could be used at least in part to
catch the mistakes. The problem of the overflows from combined sewers,
'37
-------
of course, is one which is attacked directly by this method of pro-
viding storage at the treatment plant.
The matter of duration of storage is important, because long periods
of storage would require facilities for keeping the water aerobic. We
found that the duration of storage is typically a matter of several
days, which would require aeration. Because of the large fluctuation in
the depth of water in the storage zone (particularly if it is going to
be underground storage) we felt that there should be new methods for
aerating these deep flows. One of the ideas proposed is a floating
aerator which goes up and down with the water surface which has a
telescoping draft tube on it so that the entire depth of the flow is
(or depth of the water stored) affected by the currents produced by the
floating aerator. The soltds that would be deposited in these locations
would require handling. We envisage separate solids handling facilities
and separate pumps to receive the material from a bottom scraping mech-
anism.
This concept is basically a very simple one. It has not been applied
to sewage treatment plants in the past, I believe, largely because
there was no economic incentive to do so. The economic and performance
factors are changing; we are spending a great deal more per million
gallons per day capacity now as we get into more and more advanced forms
of treatment. The rules of the game have also changed, and now we're
talking not about what our average percent removal is, but we're talk-
ing about the impacts on the receiving stream—whether those impacts
are of short duration or of long duration.
I believe that we are going to be seeing more and more of the applica-
tion of this storage function to the treatment system and I think it
will be found in two locations—in the treatment plant, and (in the
case of long transportation systems) out at the end of the line in
order to give higher percent utilization of the sewer itself. This
type of design can very well be incorporated in new plants and old
sewers in order to gain higher utilization of those existing facilities.
QUESTION: Would you reduce the size of the lateral sewers because you
reduce the size of the treatment capacity?
BAUER; I would talk about two flow rates: one would be the flow rate
at which you would move water away from the places where it
.originated to the treatment plant, and the other would be the
flow rate through the treatment plant itself. You could have
a high flow rate to the storage, and a lower flow rate from
the storage to the treatment. Now, if I understand your ques-
tion—your saying: wny don't you store it out in the neighbor-
hoods? Yes~*and, if you did put the storage out there you
would gain a twofold benefit: you would not only reduce your
treatment plant capacity, but you would reduce your transpor-
tation cost. The only limitation that I can see to that is
38
-------
the practical limitation of size, because, if you are going
to have a good storage facility it has to be large enough to
have the solids handling and the aeration facilities with it,
and warrant some kind of attention by personnel so that you
do not want them all over the place, but at some strategic
location. I believe it would be very practical to do this
in a large system.
QUESTION: What is the storage volume of the sewers themselves?
BAUER: That is a very important factor. I know that in the City of
Detroit this has been one of their considerations for a long
time in sizing a sewer; to evaluate its effect on the treat-
ment capacity. The Racine Avenue Pumping Station (in Chicago)
has very large sewers coming to it and, as I recall, they
amount to something like a quarter of an inch or so, a fairly
substantial amount of storage, maybe a quarter of an inch
spread over the watershed. The minimum that we are thinking
about for the Deep Tunnel plan I believe is 1 in.; so, you
see that existing storage in some of these large interceptors
can be a very substantial fraction of that. In the design
of the system that certainly has to be taken into account.
I am talking storage, in addition to the storage that you
would have anyway, because of the volume of the system.
QUESTION: What are the costs of pumping the water to the surface?
BAUER: Those costs were included in the cost of storage; we cap-
italized those costs. I think we took the annual cost and
multiplied by 15 in order to get the equivalent capital cost.
As I say, the $1.50 included an allowance for the pumping
from the lower elevation.
QUESTION: What about the $5?
BAUER: That $5 figure corresponds to a concrete box constructed
near the surface and includes a small allowance for pumping.
QUESTION: What about the effect upon the activated sludge process be-
cause of bringing in the stored sewage?
BAUER: We are talking about 1.25 ratio of total flow to average
flow so that the capacity of the treatment would be 1.25
times dry weather flow, assuming we had all the storage re-
quired. We would be adding sewage that had already been
partially treated as it would be aerated down below. There
would be a drop-off in the BOD. This would mean that some
of the food for bacteria would have already been used up and
would not be available for the bacteria that were operating
in the activated sludge plant. However, it may be that the
39
-------
amount of variation In food suoply with storage would be less
than without storage. We have no way of proving that and I
think it is something that could be studied, it would be very
interesting. Such a study would actually stimulate the aging
of the sewage and add it to fresh sewage to see what effect it
had on treatment. Implicit in my studies to date is the as-
sumption that there would be no fundamental change because of
the addition of the aged stored sewage.
QUESTION: Would there be a different strain of bacteria developed in
the Deep Tunnel and could these be consistently introduced
into the treatment plant? What would be the effect on the
treatment process?
BAUER: This has not been evaluated so I do not have any way of an-
swering your question.
QUESTION: Have you related the savings in treatment plant costs for the
combined sewer area that the Sanitary District serves to this
figure (figure $600 million to one billion for various ram-
ifications of the Deep Tunnel and Underflow Plan)?
BAUER: Yes, we did make an analyses of that. If you did not have
any storage and you were to design for two times dry weather
flow, as I recall, the total combined treatment plant capacity
(for the Chicago Sanitary District) would be 3600 mgd. If
we were to--by regulating flows through these plants—reduce
that required capacity to 1.25 times dry weather flow, then
the saving would be something like 1350 mgd. Now the cost
of this incremental plant capacity that would not have to be
constructed, assuming advanced forms of treatment would be
required, would be say $400,000 times 1350 = $540 million.
If that is the ballpark figure that we are in, and there is
a savings of something on the order of $500 million in treat-
. ment plant capacity, because of the regulation afforded by
storage, that becomes a very significant cost factor. It
was not really emphasized in the work that has been done so
far; I think partly for the reason that there was no pilot
plants to demonstrate this effective reduction. On the basis
of the analyses made here, I am assuming that we do not have
the kind of effect that Mr. Leary mentioned; but, I think
that kind of effect has to be evaluated before you could say
for sure that you could save that much in treatment plant
capacity. At any rate, it is a large number.
BACON: I think there is something else that should be added here;
it is not just a matter of cost. In the Chicago area where
they have gone quite far in a rapid sand filtration of u
rather crude type and with micro-strainers, it has been
demonstrated that we can no longer tolerate these wild
-------
fluctuations in the secondary effluent ranging from 15 ppm
BOD and 25 ppm of suspended solids to twice those figures
and still come off with a consistent tertiary effluent.
BAUER: I think we found that if we did get into micro-strainers which
could be an extremely economical type of tertiary treatment,
they just will not take an inconsistent or double loading
from a secondary treatment. So, in a sense the high standards
of 4 ppm of BOD and 5 ppm of suspended solids cannot be
achieved without storage. You are going to have to go into
tertiary facilities with something more uniform and,
therefore, it is not only a matter of cost figures, but a
matter of consistency of the load application to the tertiary
facility. I do not see that there is any doubt in the world
in the Chicago situation that this fact has been demonstrated.
Consequently, whether you are going to use storage to get a
more uniform result in flow to the tertiary or whether you
are going to go back to the primary and secondary and use
such things as chemical treatment to try to come out of the
secondary with a more consistent effluent remains to be seen,
but, it is more than just a matter of cost.
I neglected to mention that in the Chicago tunnel plan there
are also some surface storage facilities which are large
dyked areas for the storage storm water. These have a much
lower unit cost than I have calculated here and I think if
it is possible in any area to use an uncovered open earthen
vessel for the temporary storage that it is so economical as
to make the storage extremely attractive. I assumed in the
cost analyses in this report that it would not be possible;
it would require either a concrete box with a lid on it or
underground storage. But is is true that the regulation of
the flows has a great deal of benefit.
-------
POLLUT/OM
-f-
(V)
fc
K
1
K
I
Co
\
-------
?0
60
BOD AT VARIOUS FLO1// RANGES
ACTIVATED SLUDGE PLANT EFFLUENT
SOUTHWEST SEWAGE TREATMENT WORKS
1966 and 196?
1.0
10 20 30 1.0 60 80 90 93' 98 99 09.5
PERCENT OCCURRENCE EQUAL TO OR I.KSS THAN
Fig. 2
-------
% SPILLED (SHAD
OR STORED IF
Y WUULU
BE LIMITED TO
1.33 " D.W. F
PARK AVE. -1
VILLAGE OF
BENSENVILL
INFILTRATIC
1 ?
-------
JULY . AUGUST SEPTEMBER
j
i
r
n
n i ' -
1
i
0 n
OCTOBER
NOVEMBER
DECEMBER j
II : rvjiJ
IFT STATION
FT STATION
ENSENVILLE
, ILLINOIS
J STUDY
[He. V.Ei 1-vOPOLiTAX
SANITARY D;STR;CT OF
GREATER Ch iC-AGO
RC'-H Cr SiCRAGi ,N
SEV.'AGE TR£-\T'/E\T P;_AM
V.AXiMUM DAY
-------
246
STORAGE VOLUME - M.6.
NOTE: BASED ON ANALYSIS
OF SANITARY DISTRICT
OF BLOOM TOWNSHIP
OPERATING RECORDS.
Fig. 4
-------
QJ
~
:-
550
250
200
• 150
•
c
CS>
^J-
To Lai runoff from AiN
ston-s = 2,977,659 AF
100 -
CJ
-
50
Excess treatment
capacity
375 mgd
,
TOGO
1500
Figures in () show the number
of events in which spillage
occurred.
— 7
r<>
0
-
-
-
.
•
:
Storage Capacity - inches
Total Spillage MS Storage Capacity
i-1 q.
-------
TERTIARY
a ADVANCED
TREATMENT
SECONDARY
TREATMENT
WATERWAY
PUMPING
STATION
RETURN LINE
FROM STORAGE
.
OVERFLOW DEVICE
FOR SURPLUS FLOW
PRIMARY
TREATMENT
INFLOW
POSSIBLE STORAGE
OF STORMWATER
FLOWS NEAR SOURCE
UNDERGROUND
AERATED
STORAGE
LL-'_
SIMPLIFIED SYSTEM FLOW DIAGRAM
\
MEAN
DAILY FLOW
DOJMESTIC WASTJE.
AVERAGE MAXIMUM DAY = 1.50,
MAXIMUM DAY, DOMESTIC
WASTE PORTION,
05 10 15 20
TIME - HOURS
DOMESTIC WASTE WATER VOLUME STORED
DURING MAXIMUM DAY
Fig. 6
-------
Section 4
THE IMPACT OF THE DEEP TUNNEL PLAN Or<
WATER RESOURCES IN THE CHICAGO AREA
Victor Koelzer
Chief, Engineering & Environmental Science
National Water Commission
Arlington, Virginia 22203
-------
THE WATER CONSERVATION ASPECTS OF THE DEEP TUNNEL PLAN
FOR THE CHICAGO AREA
SUMMARY
The Harza-Bauer proposal of a Deep Tunnel Project for the Metropolitan
Sanitary District of Greater Chicago is designed to provide temporary
storage for storm water and its accompanying pollution load. Tunnels
and storage areas would be excavated in solid rock at elevations varying
from 250 to 800 ft. below ground level. They would hold storm runoff
which now floods basements and viaducts and pollutes streams in the area.
On cessation of the storm, the stored water would be pumped to the
surface and then to the District's treatment plant. After treatment,
it would be returned to the rivers and streams of the area.
The attached paper describes the impact of the Deep Tunnel Project on
two aspects of the water resources of Northeast Illinois - surface
water and ground water. It shows that the benefits to conservation of
water could be as significant as those originally expected for flood
and pollution control.
For surface water, it is estimated that the Deep Tunnel Project would,
in effect, ultimately make available an additional 515 cfs (332 mgd)
for use in the Northeast Illinois, because of better regulation and
complete treatment of storm water overflows. This compares with about
1,700 cfs of present pumpage from Lake Michigan for domestic and in-
dustrial use. The value of this water, when fully used, is estimated
to range from $3.6 million to $6.0 million annually for each 100 cfs
(65 mgd), depending on alternatives. This would justify a capital
investment, if staged to meet uses, of $18 million to $86 million,
depending also on interest rates to be used, for each 100 cfs.
For ground water, the paper describes elaborate measures planned to-
protect the aquifers, presently sources of about 130 mgd of the
metropolitan area supply, from pollution by the Project. It demon-
strates how the Project could serve as a management vehicle to reverse
the trend of ground water "mining" in the metropolitan area.
My paper is on the subject of the water conserving aspects of the
Deep Tunnel Project for Chicago, made possible by the complete
treatment and controlled releases of storm water overflows. The
National Water commission, of course, has a very great interest in
conservation of water—in fact, one of our principal studies is on
methods of conserving water.
However, while I, as a member of the Commission's staff, have great
interest in the Deep Tunnel Project from that viewpoint, I must make it
clear that this paper stems, not from any studies I have been associated
51
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with while with the Commission—rather it derives from studies made
under my supervision while I was with the Harza Engineering Company.
Most of the information was contained in a 1969 Harza-Bauer report'.
The views expressed hereafter are my own, and not those of the Commis-
sion.
THE DEEP TUNNEL PROJECT
The details of alternative proposals for deep tunnels in the Chicago
area have been described by other participants in this Institute. The
concepts of water conservation that are presented in this paper are
those which apply to the Harza-Bauer "Deep Tunnel Plan," as proposed
to the Sanitary District . Some of the concepts also might apply to
other plans for deep tunnels--these will be touched on briefly later
in this paper.
Although the details of the problem and of the Harza-Bauer plan are
presented in other papers, a brief discussion is presented here for
completeness.
THE PROBLEM
Nature has treated the Chicago area very poorly in providing for handling
of storm water and the accompanying pollution load. The flat topo-
graphy and the low gradients on most of the small streams have always
caused difficulties in drainage. In its natural state, much of the
Chicago area was a swamp.
The early sewer systems in the Chicago area were combined sewers,
intended to handle both storm water and raw sewage. This practice
has continued, for the most part, until the present. The present
combined sewer system serves 300 square miles of heavily populated
area.
In time of storm, the capacity of the sewer and treatment system is-
too small to handle both sewage and storm water. Therefore, during
such periods relief is obtained by discharge of the mixture of storm
water and raw domestic and industrial sewage to the Illinois Waterway
system. The overflows from the combined sewer system enter the Waterway
at some 400 locations, as shown on Figure 1.
"The Impact of the Deep Tunnel Plan on the Water Resources of
Northeast Illinois," A Report by the Harza Engineering Company
and Bauer Engineering, Inc., prepared for the Metropolitan
Sanitary District of Greater Chicago, February 1969.
2 Ibid.
52
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When the overflows are too large for the Waterway system to accomodate,
it is necessary, on rare occasions, to discharge this mixture of storm
water and sewage to Lake Michigan. Such a discharge occurred on
August 16, 1968, causing Chicago's beaches to be closed on one of the
hottest weeks of the year. While such occasions have been rare (only
four times in the last 25 years), they are detrimental to recreational
activities of the area. Associated with this, on many occasions, has
been flood damage along the waterway.
Locally, the increased runoff which has accompanied urbanization has
overloaded the small sewer capacity before it can be relieved at their
overflow points on the Waterway. In suburban areas, capacities of
local streams which serve as outlets also are limited. Because of
these limitations, relief occurs locally, both in the city and the
suburbs, by temporary storage on streets, underpasses, and basements.
Since this water is frequently polluted, it is a health hazard as
well as a property damage hazard.
DESCRIPTION OF THE DEEP TUNNEL PROJECT
The general concept of the Deep Tunnel Project is relatively simple,
as shown on Figure 2. It combines certain features of what has become
known as the "City of Chicago underflow" concept with underground
storage, treatment, and hydroelectric power generation. Basically, the
Deep Tunnel Project involves:
a. Providing lower outlets for existing and proposed new main
sewers and interceptors, which will increase sewer capacities
by increasing their hydraulic gradients.
b. Intercepting, conveying, and storing combined sewer overflows
that might otherwise overflow to the waterways.
c. Releasing the stored waters at a reduced rate, first to an
advanced waste treatment plant and then to the waterway.
This will virtually eliminate both pollution and flooding in
the waterways due to storm water overflows.
Ultimately, the Deep Tunnel System is proposed to service the entire
area of 300-square miles of combined sewers that are shown on Figure 1.
The First Construction Zone, as originally proposed, would serve 62
square miles in the Lake Calumet area. Since the original scheduling,
a second zone which would serve an area on the North Branch of the
Chicago River has been planned for concurrent construction with the
first zone. The proposed system for the entire service area, including
the Calumet and North Side areas, is shown on Figure 3. The service
area of the First Zone and a general layout of the project features are
shown on Figure 4.
The Deep Tunnel System will start with the capture of storm water
overflows from combined sewers at a point just upstream of the outfall
to the waterway. These polluted overflows, instead of entering the
53
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waterway, will be dropped through vertical shafts into a network of
smooth tunnels under the waterways, located at two principal levels,
in the Niagaran and the Galena-Platteville dolomites. The tunnels,
designed for flow under pressure (to utilize the large head available),
will conduct the overflow water to a central, mined storage reservoir,
some 830 feet below the land surface. The mined storage reservoir,
made up of large, unlined chambers in the Galena dolomite, will consist
of two sections, a settling chamber and the main storage reservior.
Water will first flow into a settling chamber, which will be large
enough to contain runoff from small and medium storms, and retain much
of the solids loads of large storm runoffs. The partially treated
water will then flow into the main storage reservior, from where it will
be pumped through reversible pump-turbines to a diked reservoir on
the surface, using off-peak power. Storm water stored in the surface
reservoir will further improve in quality due to sedimentation and
oxidation, and will then be fully treated and released gradually to
the waterways. In this process, the Deep Tunnel System will eliminate
99.5 percent of the pollution load presently reaching the waterways
through storm overflows from the sewers.
Both the surface and lower reservoirs will serve the dual function of
storm water retention and storage for hydroelectric power generation.
These uses are compatible. Analyses based on 96 years of rainfall
records indicate that hydroelectric generation would be curtailed less
than 0.1 percent of its operating time due to storm water retention.
TYPES OF IMPACTS ON WATER RESOURCES
Although the Deep Tunnel Project was conceived initially as a flood
control and pollution control project (with incidental power generation
facilities), it has an impact on the water resources of the area of
considerable importance. In the future, as the Chicago area becomes
increasingly in need of more water, this impact could emerge as being
fully as significant as the "primary" purposes of flood and pollution
control.
There are two ways in which the Deep Tunnel Project would have an
impact on the water resources of Northeast Illinois. The first is in
conservation of surface water resources, the second is in management of
ground water resources. Each will be dealt with separately in the
following sections.
IMPACT ON THE SURFACE WATER SUPPLY
THE PRESENT SUPPLY
The surface water presently available to the Northeast Illinois area
consists primarily of the supply from Lake Michigan. Prior to 1967,
there was no limitation on the amount of domestic anc industrial
pumpage from Lake Michigan by the City cf Chicago and a privileged
few of its suburbs. However, the 1967 decree of the U.S. Supreme
-------
Court has made the surface water supply much more critical, by intro-
ducing new limitations. While the amount of water that could be pumped
from the Lake would be unlimited if it were possible to return the used
water to the Lake, such return is considered unacceptable under present
conditions because of potential pollution of the Lake. Under present
conditions, the only acceptable procedure is to direct the water, after
it is used, down the Illinois Waterway.
The amount of diversion from the Lake to the Waterway is now limited by
the 1967 decree to a total of 3200 cfs (2,060 mgd). The decree defines
three components that must be counted in such diversion. These
components are as follows:
a. Domestic pumpage (including water supplied to commercial
and industrial establishments but excluding well pumpage),
the sewage effluent derived from which is not returned to
Lake Michigan. This component has been estimated to
average 1,734 cfs (1,110 mgd) during the 1950-1964 period.
b. Storm runoff which, without the interception by the canal
system of the Metropolitan Sanitary District, would have
entered Lake Michigan from the natural drainage of the Lake
Michigan watershed. This component has been estimated to
average 550 cfs (355 mgd) during the 1950-1959 period.
This was prior to construction of the O'Brien Lock, when the
area intercepted in this manner was about 450 square miles.
The Sanitary District feels that the Special Masters'
estimates are high—that the correct figure is more in the order
of 400 cfs. The District feels that the 550 cfs is more
applicable to current conditions, with O'Brien Lock, where
the area of normal Lake Michigan drainage that is intercept-
ed is about 740 square miles.
c. Direct diversion from the Lake into the canal system of
the Sanitary District, estimated to average about 945 cfs
for the 1950-1964 period. (Since the total of the three
components has historically been 3,229 cfs, it can be
presumed that this component would have to be reduced by
29 cfs, to 916 cfs, to comply with the decree.)
The total amount of water to be diverted from Lake Michigan (3,200 cfs)
presently serves the purposes of (1) municipal and industrial water
supply, (2) maintaining sanitary conditions in the Illinois Waterway,
and (3) navigation. The 1967 decree of the Supreme Court specifies that
the State of Illinois may apportion the 3,200 cfs among these uses as
it sees fit, subject only to any regulations imposed by Congress in
the interest of navigation or pollution control. Thus, the 1,734 cfs of
J Report of Albert B. Maris, Special Master, to Supreme Court of the
United States, Wisconsin et al, vs Illinois et al, Dec. 8, 1966, p. 87,
4 Ibid., p. 87.
5 Ibid., p. 87.
55
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"domestic pumpage" can be increased if the needs of navigation and
pollution control are adequately cared for with their reduced supply.
In addition to surface water diverted from Lake Michigan, there is an
undeveloped source of water in streams naturally draining away from
Lake Michigan. This supply is quite erratic in its occurrence, and
would require substantial storage facilities for regulation. Major
streams which might be utilized in this manner include the Des Plaines,
the Fox, and the Kankakee. Reliable cost estimates are not available
for the storage and transmission systems that would be required, but
they undoubtedly would be very expensive.
Another method of utilizing the above rivers, proposed by the Lake
States which opposed Illinois in the suit before the U.S. Supreme
Court, would be to divert water into Lake Michigan from the rivers to
compensate for water diverted from Lake Michigan. The cost estimates
by the Lake States are believed by Illinois to be quite low and the
feasibility of making compensating diversions from the three basins,
of the magnitude suggested, are open to serious questions.
THE NEED FOR WATER MANAGEMENT
•
The 1967 decree of the Supreme Court provides that application for
modification of its terms can be made only if the State of Illinois
demonstrates (a) that the ground and surface water resources of the
region are not adequate to meet the needs, and (b) that all feasible
means that are reasonably available have been employed to conserve
and manage the water resources of the area.
The terms of the 1967 Supreme Court decree are very positive in stating
what Illinois must do if it ever wishes to obtain more than 3,200 cfs
from Lake Michigan. Mr. W. C. Ackermann has been very active in pointing
this out. He has stated:
It is perfectly clear, however, that the State of Illinois has
the duty so to manage its water resources and regulate the use of
the water now available to it as to conserve this essential commo-
dity to the utmost practicable extent for the use of its people.
This surely means that the State must definitely undertake the
task of managing its water resources, at least in its Northeastern
Metropolitan Region, on a broad regional basis in the most modern
scientific manner and that all feasible methods for developing the
supply and conserving the use of domestic water which are reason-
ably available to it should be employed, before the State receives
authority to divert more than the present 3,200 cfs from Lake
Michigan.
6 "Implications of the Maris Report," W. C. Ackermann, Chief Illinois
State Water Survey, A talk prepared for the Great Lakes Water Resources
Conference in Toronto, Canada, June 25, 1968.
-------
CONSERVATION OF STORM RUNOFF FROM DES PLAINES WATERSHED
In addition to the - rmwa^er overflows in the Lake Michigan natural
watershed, signific overflows that occur in Des Plaines River
watersheds will be turecl by the Deep Tun;^! Project and treated.
These overflows ar. .-om an estimated 60 $•:. ;tre miles of the 300
square mile combine, sewer ... - , T,-. • -ver .ws are estimated to be
the same as from the Lake Michigan Woo-; :! •:, on a cfs-per-square-mile
basis, and thus would be about an average of 50 cfs (32 mgd).
Since the origin of this water is from outside the Lake Michigan
watershed, it is not charged againiv. .'"Mnois1 diversions from that
watershed. In fact, since it would ultimately be discharged into
Lake Michigan, or accomplish the equivalent thereof, it would be an
import into the basin, to serve as a credit against diverted water.
The Sanitary District has recently adopted resolutions which eventually
could lead to providing flood control storage on a number of small
streams, outside the combined serviced area, which enter the Waterway.
These streams, which drain approximately 1,260 square miles, would be
controlled in a manner that would require releases to be made in a
matter of a relatively few hours, or days at most, after a storm.
Thus their releases could not be used directly as a supply of water.
It seems possible, however, that as the Northeast Illinois area
becomes more restricted by the limits of the decree in relation to-
growing water needs, some coordinated operation of the Deep Tunnel
system and such flood control reservoirs could be accomplished.
Flood releases from these reservoirs might be made directly to the
Deep Tunnel system for all except the major storms, in effect creating
additional imports to the Lake Michigan watershed. Such coordination
of operation probably could be made feasible, without any loss of
dependable power capacity, because it could be done at a time in the
future when the power load curve is such that the number of kilowatt-
hours of energy (equivalent to the water storage volume usable for
power) would be significantly less than initially.
CONSERVATION OF PRESENT DIRECT DIVERSIONS TO THE WATERWAY
The water diverted directly to the waterway system (estimated to average
945 cfs, but assumed to be decreased to 916 cfs to comply with the
decree) is used for navigation and maintenance of sanitary conditions.
Although the Corps of Engineers has not stated what it considers to be
the minimum amount necessary for navigation, it has stated that the
total present diversions would be adequate to meet future navigation
requirements, with the improvements it contemplates for the future.
The Deep Tunnel Project will give complete treatment to storm water
overflows, which have contributed heavily to unsanitary conditions in
the waterway. The Sanitary District also has programs aimed at
57
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eliminating the adverse effects of the other two main sources of
waterway pollution (sewage plant effluent and industrial wastes).
The present sewage plant effluents are expected to be given advanced
waste treatment processes. The industrial waste pollution is being
eliminated by measures taken by industry, under the legal requirements
of the recently adopted waterway standards being enforced by the District.
After these steps are taken, there will no longer be a need for
diversions to maintain sanitary conditions. There will remain a need
for direct diversions to serve navigation, since water will be needed
for lockages at the mouth of the Chicago River and at the O'Brien Lock
on the Calumet River. There will also be leakage through these
locks. The combined amounts of water needed for such lockage and
leakage at the mouth of the Chicago River and at the O'Brien Lock has
been estimated as being 130 cfs'. The Sanitary District has estimated
the requirements for lockage and leakage at Wilmette to be 20 cfs.
Thus, the total lockage and leakage requirements would be about 150 cfs
(100 mgd).
It probably would be possible to conserve most of the lockage and leakage.
However, as a minimum, there would be in the order of 765 cfs (the 916
cfs of direct diversions diverted minus 150 cfs) which could be added
to the region's usable water resources if all three sources of pollution
were eliminated. The Deep Tunnel Project cannot claim credit for all
of these savings, since other measures are also necessary. However,
it could, on the basis of percentage of pollution eliminated, claim
credit for conservation of about one-third, or 255 cfs (165 mgd).
EFFECTS ON NAVIGATION DOWNSTREAM
The 210 cfs of storm water runoff in the Lake Michigan watershed, plus
the 50 cfs originating outside the watershed, if converted to a usable
water supply, would eventually return to the Illinois Waterway and would
be uniform in flow, rather than occurring erratically in storm periods,
as at present. This would benefit navigation significantly. The 765
cfs of direct diversions that is saved, if used as municipal and in-
dustrial water supply, also would return to the waterways. Thus the
total average water available at Lockport and downstream locations
would be same as at present, but would be better regulated and vastly
improved in quality.
SUMMARY OF EFFECT ON SURFACE WATER SUPPLY
On the basis of the above estimates, the Deep Tunnel Project would make
available the following additional quantities of water for municipal and
industrial use:
From the storm water originating
within the Lake Michigan watershed 210 cfs 135 mgd
7 Maris Report, p. 86.
58
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From storm water originating out-
side the Lake Michigan watershed 50 cfs 32 mgd
Savings in present direct
diversions 255 cfs 165 mgd
TOTAL 515 cfs 332 mgd
This increase in usable water supply from the existing water resources
of Northeast Illinois is more than one-half the 930 cfs of additional
water needed to serve the growth in population in the Metropolitan
area by the year 2000, as estimated in the report by the Special
Master8.
STAGING OF USE OF ADDITIONAL WATER
The water conserving potential of the Deep Tunnel Project is ideally
suited to staging of use of the water, as the needs of the Chicago
Metropolitan area grow.
The plan outlined herein is based on the Harza-Bauer plan of 1968.
Since that time, it is understood that agreement has been reached to
proceed with an "underflow" concept for an area of the North Shore
channel, from approximately the junction of the North Branch of Chicago
River to the Wilmette inlet; While this will have less storage (about
1.25 inches as compared to the 2.2 inches provided in the Deep Tunnel
Project), it will capture a significant percentage of the overflows.
Since the captured overflows will be given additional treatment, their'
release to the waterway will contribute to the cleanup program.
The first stage of conservation through the Deep Tunnel system might
be the substitution of the storm water releases that are treated in
the North Shore channel phase for an equal amount of direct diversions,
presumably on the basis that equivalent sanitary conditions would
obtain. The writer does not have specific knowledge of the area to be
served by the North Shore channel phase, but it could provide a saving
of 10 to 15 cfs (6 to 1 0 mgd), sufficient for a population of about
70,000 to 100,000 (at a usage rate of 100 gallons per capita per day,
which is higher than the present usage in most Chicago suburban areas).
The next step could be upon the completion of the initial storage for
the Deep Tunnel Project, under the mined storage concept conceived in
the Harza-Bauer Plan. This could either be in the Calumet area or in
the McCook area (see Figure 3), either of which seems to be feasible
extensions of the underflow phase for the North Shore channel area.
At that time the additional water salvaged, approximately 40 cfs (25
mgd) if the First Zone of Figure 4 is developed; could be made
available immediately by releasing it directly to the waterway as a
replacement for an equal amount of direct diversion. Since it would be
8 Man's Report, p. 102.
59
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fully treated, the 40 cfs that would be saved could be used
for municipal and industrial purposes.
Ultimately, when the Deep Tunnel Project is completed, the 260 cfs
(168 mgd) of storm water runoff that would be salvaged could be put to
use in the same way. This amount would be sufficient to support an
additional 1,700,000 persons (at 100 gallons per capita per day).
The next step after use of the 260 cfs would be to utilize all of the
savings in direct diversion that can be used without installing addition-
al transmission facilities. The 260 cfs of captured storm water will
not be released uniformly to the waterway throughout the year—our
studies indicate this would vary from zero to a maximum of 562 cfs.
The direct diversions would be increased or decreased as necessary to
compensate for the changes in rate of release of treated storm flows.
Any direct diversions that may be saved as a result of complete
treatment of all sources of pollution (storm water overflows, waste
treatment plant effluents, and industrial wastes) would be staged
after the preceding stages are utilized.
Additional future steps could involve conveyance of all the captured
storm water back to the lake for regulation to uniform flow throughout
the year, or capture of additional storm water from reservoir releases
in areas outside the combined sewer area. Thus the Deep Tunnel Project
fits in ideally to a staged development of providing additional water
supply, as the population of the area grows.
VALUE OF WATER CONSERVED
The value of the resource that would be conserved is dependent on the
alternative cost of water supply that might be available. This has not
been determined reliably for the Chicago area, but several yardsticks
might be used as the basis for an appraisal. These are:
a. The average cost of water delivered to all communities in the
U.S. (including transmission but not distribution costs),
estimated to be 12 cents per 1,000 gallons.
b. The anticipated cost of the necessary steps in advanced
waste treatment (over the cost of secondary treatment) to
provide water suitable for reuse for municipal and industrial
purposes, which is estimated to be about 25 cents per 1,000
gallons (excluding transmission and distribution).'
c. The cost of providing water to suburban areas (including
treatment), by pumping from ground water, estimated to be
15 to 25 cents per 1,000 gallons.
information in draft of report on this subject by National Water
Commission.
60
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In addition to the above, the Lake States estimated the costs for water
diverted to Lake Michigan from the Fox, Des Plaines, and Kankakee Rivers,
to be 2-1/2 to 6 cents per 1,000 gallons, not including treatment. As
indicated previously, these estimates are believed to be quite low and,
therefore, have not been used in the subsequent analysis.
The justifiable capital expenditures for measures to provide the
additional water (assuming it were immediately useful upon completion
of the facilities) would also depend on the terms of amortization of
the facilities (primarily on the interest rate assumed) and the allo-
cation of operating costs to the water conservation purpose. For
purposes of illustration, the justifiable capital costs are presented
in the following table on the basis of annual charges (debt service
plus operating costs) of 7, 10, and 12 percent.
TABLE #
Value of Conserving each 100 cfs (65 mgd)
Source
Alternative Costs Annual Value Justified Capital Expenditure
(Cents per (millions of for various annual charges
1,000 gal.) dollars) (in millions of dollars)
7%
10%
12%
Average in U.S.
From Advanced
Treatment
Present Cost to
Suburbs
12
25
15-25
2.1
6.0
3.6-6.0
30
86
51-86
21
60
36-60
18
50
20-50
It must be recognized that the above values are attainable only when
there is a definite market use for the water, at the prices indicated.
Such uses will build up only gradually, over a period of years—hence
the values are shown for 100 cfs increments, to avoid the inference that
the complete capital expenditure to provide a total saving of 515 cfs
(332 mgd) is immediately justified. It will be necessary to make a
reliable appraisal of the buildup in uses and the resulting cash flow, to
develop a dependable basis for the justifiable staging of capital expenditures,
IMPACT ON THE GROUND WATER SUPPLY
EXISTING RESOURCES AND USE
The principal aquifers supplying the metropolitan area are, in order of
depth, the sand and gravel deposits of the Glacial Drift, the Silurian
dolomites limestone, the Cambrian-Ordovician sandstones and dolomites,
and the Mt. Simon sandstone. A description of these systems is given
on Figure 5.
In 1967, total ground water pumpage in an eight-county area of Northeast
6l
-------
Illinois was 243.7 . Of these, 29.5 mgd came from sand and gravel
wells, 84.3 mgd from shallow dolomite (Silurian) wells and 129.9 mgd
from deep sandstone wells. It is estimated that of the 129.9 mgd
pumped from deep wells, 74 mgd came from the Cambrian-Ordovician
aquifer and 55.9 mgd from the Silurian and Mt. Simon aquifers, through
wells which are also open to these two aquifers.
Over 175 municipalities obtained their supply from ground water in
1967, using a total of 148.5 mgd. The remainder of ground water usage
was by industries, 61.8 mgd, and by irrigation and domestic users,
33.4 mgd.
The Silurian system has been estimated by the Northeast Illinois Planning
Commission to have a supply considerably in excess of present pumping
requirements. However, this system is quite erratic in the occurrence
of ground water at specific locations, especially within the metro-
politan area, so that there is considerable risk of dry holes when
wells are drilled. For this reason, the Silurian aquifer is only
partially used.
Contrasted with this, the Cambrian-Ordovician aquifer is highly
dependable as a source and also has a lower hardness. A village or
industry can be assured of a good yield when it makes the investment
necessary to drill a well. This aquifer system, therefore, is the most
widely used and pumpage from this system has increased from about 25 mgd
in 1940 to 74 mgd in 1967. Major centers of heavy pumping are at
Des Plaines, Elmhurst and Summit. Because of this heavy usage, the
withdrawals of ground water from the Cambrian-Ordovician system have
exceeded the supply available through natural, recharge, by some 60
percent. As a result, water levels have declined from artesian flow
in 1864 to depths of 650 ft. in 1966. The rate of decline of the
ground water level, averaging about 13 feet per year over the area,
is indicative of the difficulties which the area will encounter if
the "mining" of ground water continues. A water level map for the
area is shown on Figure 6.
PROTECTION OF THE GROUND WATER RESOURCE
The tunnels and mined storage area of the Deep Tunnel System would be
excavated in the two dolomite rock formations underlying the area
(Niagaran and Galena-Platteville), at approximately 250 and 800 foot
depths below the ground surface. The tunnels would be in these two
separated rock units, which are part of two completely separate ground
water systems, while the mined storage area would be only in the lower
aquifer. The proposed Deep Tunnel System includes elements which have
been designed to protect these aquifers from any deleterious effects
of the storm water runoff that would be conveyed in the tunnels and
stored in the mined area.
Personal communication, R.T. Sasman, Illinois State Water Survey,
to Harza Engineering Company.
-------
The principle on which the protection is based is extremely simple--
even though the implementation of that principle is somewhat complicated.
The principle is simply that water will not flow "uphill," that is,
against a positive pressure. The principle is demonstrated in Figure 7.
It will be implemented by assuring that the water pressure in the ground
water surrounding the tunnels and mined area will always be greater
than the pressure inside the tunnels and mined area. If this is the
case, any flow of water that occurs must be inward, toward the tunnels,
not outward. Under such conditions, pollution of the aquifer cannot
occur.
The protective system that has been devised has been based on extensive
ground water investigations, including an electric analog computer and
field drilling, seismic surveys, well logging and pump tests, all of
which were obtained at a cost.of about $2,000,000.
The upper level tunnel system in the Harza-Bauer plan would be below the
water level in the upper aquifer system. The tunnels would not be
allowed to become pressurized above the outside ground water pressure.
The upper aquifer is used only slightly, and, as a result, the supply
of ground water available from infiltration of precipitation on the
land surface, i.e., natural recharge, is much larger than present
pumpage from this aquifer. It is also anticipated that future pumpage
from this aquifer would not exceed the natural recharge. Therefore,
the ground water pressure in the upper aquifer system would remain
greater than the pressure in the tunnels, and pollution of the aquifer
cannot occur, as shown on Figure 7(A).
Protection of the lower, completely separate, aquifer would require
slightly different measures. The ground water in this aquifer is
presently above the elevation of the lower tunnels and the mined
storage area; however, as indicated previously, because of heavy usage,
the ground water level is gradually falling, at an average rate of
about 13 feet per year throughout the area. To adequately protect the
lower aquifer, this trend must be reversed so that the piezometric '
level of the ground water will always be above the level in the tunnels
and the mined storage area. The principle of protection for the lower
aquifer is demonstrated on Figures 7(B) and 7(C).
Two measures are possible to maintain the pressure in the ground water
above that in the tunnel and mined area. These are (1) artificial
recharge of the aquifer, and (2) control of ground water pumping.
A recharge system is entirely feasible, would use relatively small
quantities of surface water for recharge, and would not necessitate the
exchange of a surface water supply for a ground water supply with present
users. Most of the recharge water would move toward existing wells,
thus augmenting the available supply. The validity of the recharge
approach has been demonstrated by studies which included a $487,000
ground water drilling and testing program, construction of an electric
analog computer, and office evaluation of collected data and analog
63
-------
results. Additional subsurface information, obtained through the
geologic investigations of the area, included a $437,000 diamond core
drilling program, and a $1,006,000 seismic exploration and geophysical
well logging program. The results of all these field investigations
were incorporated into the ground water studies.
The second method of protection, which may ultimately prove to be highly
practical, would be to manage ground water pumping in the area in such
a manner that ground water levels will be maintained at a high enough
level to assure that the water level outside the storage area is higher
than inside. This would require substitution of a surface water source
of supply to a portion of the users now pumping ground water. As ex-
plained previously, it is believed that the Deep Tunnel Project would
ultimately make a large amount of additional surface water available,
so that this method would be highly promising and entirely practicable,
from an engineering viewpoint. A number of complex administrative
arrangements would be necessary to implement this approach. In effect,
this would require overall, centralized management of all of the water
resources of the Northeast Illinois area. Such management arrangements
would be complicated, but would produce significant overall benefits.
COORDINATION WITH STATE OFFICIALS
Throughout the course of the studies underlying the Harza-Bauer Plan,
Mr. William C. Ackermann, Chief of the Illinois State Water Survey,
and Mr. Clarence W. Klassen, Chief Sanitary Engineer of the State
Department of Public Health and Technical Secretary of the State
Sanitary Water Board, were kept informed on the planned aquifer pro-
tection method and on the progress of the studies.
Mr. Ackermann commented favorably on the report with respect to both
ground water and surface water aspects and was particularly interested
in the possibilities of the Deep Tunnel Project as a key vehicle for
regional ground water management. He said*1:
"Your proposed design of recharge and observation wells to main-
tain a positive pressure over the tunnels appears reasonable. Of
course, we all recognize that a rigorous program of surveillance
will be required, and if local conditions vary from expectations
it is conceivable that a few additional recharge wells or in-
creased recharge rates may become necessary.
We visualize that two general plans of management could be develop-
ed. One would be a regional one in which a special water district
would assume control over all groundwater pumpage, and could thus
control water levels over a wide area. Such enabling State laws
il Letter of February 12, 1969, from W.C. Ackermann, Illinois
State Water Survey, to V.A. Koelzer, Harza Engineering Company.
-------
exist, and we would consider this a desirable, and perhaps eventual-
ly, an essential system. The other plan of management, which you
outline, is to maintain pressures locally through recharge in the
vicinity of your proposed works.
The Deep Tunnel, if undertaken primarily for flood and pollution
control, will contribute very significantly to the objective of
demonstrating that Illinois is taking all feasible and reasonably
available means of conserving water. The completion of the Deep
Tunnel Project would be the best protection the users of ground-
water could have that their groundwater resource will be preserved,
because the control of groundwater levels in the areas of the Deep
Tunnel facilities which must accompany that Project will fit in
admirably with a management program for conservation of the ground^
water resource."
The contacts with the State Board of Health and State Sanitary Water
Board were primarily in connection with ground water protection. While
specific written comments of individuals in these agencies were not
requested, they raised no questions regarding the adequacy of the pro-
tective system that has been proposed.
QUESTION: Would you need a new distribution system to effect the re-
charge?
KOELZER: For the first construction zone, which was about 1/6 of the
area, the plan was to have 15 recharge wells. The studies
indicated these wells would be adequate to maintain the
levels.
QUESTION: In view of the fact that the first portion of storm water
contains the highest percentage of the solids, was considera-
tion given to capturing only a first portion of the overflow
rather than the total?
KOELZER: This was not done initially for the Deep Tunnel Plan as
presented to the Sanitary District, because it was believed
that the water quality standards could not be met by capturing
only the first flash. This was a criticism that was raised,
but information was not then available as to the cost.
-------
Boundary or Natural
Lake Michigan Watershed
L
CHICAGO DEEP TUNNEL SYSTEM
FIRST CONSTRUCTION ZONE
LAKE
MICHIGAN
•
COMBINED SEWER OVERFLOW POINTS
HAIZA CNGMCEIING COMfAWY DWO
tAUEl iNG.^i(HNC INC
66
Fig. 1
-------
/•Advanced treatment
Treated water -^ f /- -Sewage treatment
\ / /" Reservoir
. »>*'"" x V^^K^i?35?^
^^^=^, \ ffl "'•"'
"^~7ir
Combined sewer ' g \
y
r
; MSD interceptor -/
r
! ?
Possible underflow
1 j Tunnel ^.
" "
*
*M
li
ii
^\ — r • ^-^y= — {/•
\ — =#7ft *
wA^rtV1*
t>, i
"•5 X
/
i1 J!
V. Q,
:! .
|
^, v.
^ &
^ 1
> $
§
* t;>
> t
K ^
£
3
o;
^ Mined Storage
1
/
f »K?.— .
^
f
i
Y
5
^
v
«
^
i
fc
i
$
Flow L« saas^J p*\
\
Reversible pumped- storage j
.Hydroelectric plant. —
CHICAGO DEEP TUNNEL SYSTEM
THE DEEP TUNNEL
CONCEPT
MARZA ENOINEER1NO COMPANY OWO NO.SiTB
BAUER eNoiNeERiNa INC. 67 Fic '•
-------
NORTHWEST SUBURBS
PLAINES RIVER
AREA
DU _PAG§_ _CO»JNTY.
WIU." COUNTY
b»ctport Loctt
BAUER : -3 ~NI
-------
OE AREA
•NTRAL AREA
MICHIGAN
-RACINE AREA
CALUMET AREA
LEGEND
I J
Service area
Scol«
Treatment piont
Pumping station
Storage and treatment
Main conveyance tunnef
Mam Severs (tunnel Of conventional)
334 Miles
*'-*-•' I
GREATER CHICAGO
POLUTION AND FLOOD CONTROL SYSTEM
GENERAL MAP
69
-------
Treatment Facilities —-"
Effluent chlorination conduit
Branch No. 4
BAUER ENGINEERING INC.
HARZA ENGINEERING COMRftNY DWG. Ntt 3B7B 301
-------
.MICHIGAN
- Limits of mined
storage area f
Branch No.Z *i
I ---
— I
— V '
r
L
L~..,
rs
u
~\
LEGEND:
Conveyance tunnels in the Moyoron dolomite
Comf/once tunnels In the Galena and PtottevXIe dotomltt
Drop shaft ana" shaft number
Project drainage area
Recharge fells
Monitor wells
Scole IOOO 0 3OOO Feet
CHICAGOLAND DEEP TUNNEL SYSTEM
FIRST CONSTRUCTION ZONE
GENERAL PLAN
-------
AQUIFER
GLACIAL
DRIFT
z
;f
13
— •
tsi
Z
o
o
o
(r
o
2
cr
CD
S
o
MT SIMON
STRATA
Pleistocene
Niogaran
and
Alexandrian
Maquoketa
Golena-
Platteville
Glenwood-
St. Peter
Prairie Du
Chien,
Eminence
and
Pofosi
Franconia
Ironton-
Galesville
Ecu Claire
Ml. Simon
AVERAGE
THICKNESS
(feet)
65
too
PREDOMINANT
ROCK TYPE
WATER -YIELDING PROPERTIES
i
Till, lenses
of sand 4
grave i
Not tested. Significant deposits of
highly productive sands i gravels were
not encountered.
Very small yields of water from crevices
Dolomitic ' and solution channels. Yields range .
\ i mes t one
from less than 0.! to 1.0 gpm per foot j
of drawaowp. .
170
330
90
340
130
170
Not
penetrated
Not
penetrated
Sha le
Not water yielding, acts as Barrier
P e t w e e n Silurian 4 CamDrian-Ordovician
aquifers.
Do 1 om i te
Sand stone
Least permeable unit of the
CamDrian-Ordovician aquifer.
Yields v e :' y small amounts of
water from crevices, ranging
from less than C.I to I.I gpm
per foot of arawdown.
Yields small amounts of water
j
Do 1 om i te
Sanos t one
Sanastone
Sha ie
Sand s t one
Locally well creviced
central portion of this unit
responsible for high yields.
Yields moderate amounts of
wat e r .
Most dependable and most
productive unit of the
Camorian-Ordovician aquifer.
._•
O
cn
W t- .n
^ 0 0
-C L. SL
^ ?; -s>
- X
*- *+- 03
?i 3
O C
0 E —
— T;
"u CT %
O — ^
Q. s) ,_
~Q U
« & C
O -- r>
Z >- ~~~
~ i
Not water yieioing, acTi ?, s b a r - . e - :
Between Cambria n-Orcovician and :
Mt . S i men aquifers.
Not testec. Reported to yield IT. ooerate
amounts of wa te r .
NOTE: Water-yielding properties and
thickness oased on exploration
program in First Construction
Zone; may be different in other
areas .
CHICAGO DEEP TUNNEL SYSTEM
FIRST CONSTRUCTION ZONE
REGIONAL AQUIFER SYSTEMS
Fig.
-------
AQUIFERS IN DEEP
TUNNEL ZONE
73
-------
R6 E
: HENRY CO.
R8E
RIPE
LAKE CO. •"'•T^-~ -:-v>
R ,2E
.. _ • . . .
KANE . . .. ._.
. . • *
I- . . • ..1 ;•••••?•: -K
'•- '"•• •'.••.''• •
^v^-'^JUl^^^t^^.^V*
"•.••'•.•.'•4-'.'-:'';''|i-; 'vi'/?-'!':'.-'::•':-.:> \OaPlaines .S ^
:i/....://:.,
•:- •-.-•:::."•:?••:.
•• •• •••!/,: . - -. .-\
"• •• .v : V. •• :'.-y
r.' • • . • • •; • V Aur
""
CHICAGO
n
ARTESIAN PRESSURE DECLINE
1961- 1966
NOTES.
I. The piezometric surface represents the water pressi>
Aquifer, i.e. the level to which water will rise in a w\
2. Drawings based on Illinois State Water Survey; Sos
BAUER ENGINEERING INC.
HARZA ENGINEERING COMPANY DWG. NO. 387 B
APRIL 1966
-------
R6E
R8E
RIOE
R13E
T46 N
\2ion
T44N
CHICAGO
T38N
LEGEND:
/ Water level contour, ft
Chicago City Datum T 36 N
Contour inteval, 50 ft.
Approx. boundary of
1—.„„ First Construction
Zone
PIEZOMETRIC SURFACE
1966
Seote 0 5
lOUiles
; level in the confined Cambrian -Ordo vie/an
' penetrating the artesian aqifer.
•an, McDonald and Randall,1967
CHICAGOLANO DEEP TUNNEL SYSTEM
FIRST CONSTRUCTION ZONE
CAMBRIAN-ORDOV1CIAN AQUIFER
WATER LEVEL WARS
-------
-Water level in hypothetical pipes
shows pressure in tunnels-
/Water level
-------
"Water level in hypothetical pipes
shows pressure in tunnels
Water level in well shows artesian
pressure in Galena" Piattevilie
Artesian pressure-in-.GaJena"Fiotiev^ 16.to
main!ainecLaOhl*--!evei by -recharge
, CONVEYANCE..'.TUNNELS-.4N--—,
~ L---GALENA - PLATTEVfCLEr
(B
EXPLANATION-
Arrow indicates direction of water pressure.
CHICAGOLAND DEEP TUNNEL SYSTEM
FIRST CONSTRUCTION ZONE
PRINCIPLE
OF AQUIFER PROTECTION
77
-------
Section 5
THE POTENTIAL OF PUMPED STORAGE FOR HYDROELECTRIC GENERATION
IN MULTI-LEVEL DEEP TUNNEL SYSTEMS
by
Kenneth E. Sorenson
Vice-President
Harza Engineering Company
400 West Madison Street
Chicago, Illinois 60606
-------
MULTIPLE USE OF UNDERGROUND RESERVOIRS
FOR POWER GENERATION
USES OF RESERVOIRS
Large underground chambers excavated for urban flood control would
have relatively infrequent use, and would very rarely be fully used
as single-purpose reservoirs. One possible dual function could be
for hydroelectric pumped-storage. Another multi-purpose function
could be the circulation of condenser water for underground nuclear
generating plants.
This paper describes briefly the possibilities and implications of
such multi-purpose uses.
PROBLEMS OF THE POWER INDUSTRY
From the viewpoint of transmission and reliability, generation is
preferred close to the major urban centers. Obtaining publicly
acceptable routes for high voltage lines from more distrant plants
is becoming increasingly difficult.
In the case of pumped-storage, many large urban areas do not have
favorable topography for conventional hill-top reservoirs. And yet,
the functions of such plants for day time peaking and system reserves
are best served if close to the load centers. Even where suitable
sites are near by, preservationist opposition arises, as with
Storm King Mountain near New York City. Underground installations
could overcome both the topographical and preservationist obstacles.
Nuclear plants also present problems for urban or suburban siting,
in some cases due to unwarranted fear by the public of accidental
radioactive emissions. Warm water discharges from condensers also
have led to opposition. Underground placement of nuclear plants
can give assurances of isolation during accidents and greater pro-
tection against sabotage. Surface reservoirs of a flood control
and pollution abatement scheme might possibly serve also as cooling
ponds.
DESCRIPTION OF POWER INSTALLATIONS
A simplified section through an underground pumped-storage and
nuclear power project is shown on Figure 1. The principal elements
are:
1. An upper reservoir, lake or ocean.
2. An upper intake and discharge structure, and access
building.
-------
3. Vertical shafts for pentrocks, for access and cables,
and for chamber construction and air vent.
4. Lower level equipment chambers for reversible pump-
turbines, electrical equipment, and the possible
nuclear reactors and turbine-generators.
5. A lower reservoir serving the purnped-storage project
and the possible nuclear plant condensers.
If not part of a flood control scheme, the lower reservoir of such
a power project needs to be from 2,000 to 3,000 ft. deep to be
economical. If the excavated reservoir chamber is essential for
other than power use (e.g. flood control), the pumped-storage
and nuclear generating plant would be economical at much lesser
depths. A plan of the lower level chamber for the power develop-
ment alone is shown on Figure 2. This arrangement provides for
cooling water flow into the condensers and pumping of heated water
to the surface reservoir.
Both in section and in plan, the power development can be adapted
to a multi-purpose flood control and pollution abatement scheme.
The large pumping capacity of the reversible pump-turbines would
permit rapid evacuation of the lower reservoir after a flood. In
a single-purpose flood control scheme, equivalent large pumps would
be very expensive for their very infrequent use.
FUNCTION OF PUMPED-STORAGE
The uses of pumped-storage projects are so generally well known
that only brief mention is needed here. The major functions are:
1. Load center reserve.
2. Short-term peaking.
3. Load regulation.
4. Energy economy.
As reserves, such plants can be a source of start-up power for
thermal plants, as was needed in tie 1965 Northeast blackout.
For short term peaking and load regulation, pumped-storage plants
offer a faster response to load changes and greater efficiency under
variable loads. An example of this type of operation is shown on
Figure 3.
As more and larger fossil and nuclear fueled plants are installed,
advantages arise in the use of pumped-storage to conserve low-cost,
off-peak energy for on-peak use, with a resulting energy economy.
An example of this type of operation is shown on Figure 4.
-------
NUCLEAR POWERPLANT COMBINATION
The use of an underground reservoir for condenser water at a nuclear
plant creates complications in the configuration of the lower chamber
and in pumped-storage operation. On the other hand, the access
shafts and other power plant facilities of a pumped-storage project
could serve an economical dual function for the nuclear plant. Greater
public acceptance and the economic advantages of urban siting would
be the principal determining factors for inclusion of nuclear plants
in the multi-purpose scheme.
FLOOD CONTROL AND POWER OPERATIONS
In any multi-purpose reservoir one function takes priority, or a
compromise in functional uses is established. In the case of Lake
Mead behind Hoover Dam, compromises are made in operation, but
generally irrigation and municipal water supply have priority over
power generation. There have been years when so-called "prime
energy" from the Hoover powerplant has been only 60« of the contract
amounts.
All generating plants, whether hydroelectric or thermal-electric
do not offer 100S reliability. For the former, forced outages of
equipment are rare, but extreme low-water conditions can curtail
output. Fossil-fuel plants have more frequent equipment outages
and occasional fuel shortages. Nuclear plants have experienced the
greatest equipment failures, but no lack of fuel.
Multiple use of underground reservoirs for flood control and pumped-
storage would create some conflict in uses, and cause partial or
total reduction in generation. However, the infrequent use of the
full volume for floods would cause much less outage of generation
than is normal for other types of plants. In a study made for the
Chicago Area, reductions in generation over a 96-year historic
period would have occurred less than 0.1% of the operating time.
One example of the combined use of lower and upper reservoirs
for flood control and power generation during a storm is shown on
Figure 5. There is indicated for this rather severe storm some
curtailment in generation and a small amount of overflow of un-
treated sewage to the waterway. Neither the curtailment nor the
overflow are significant.
COSTS
Any flood control and pollution abatement scheme must be accepted
by the community on the basis of its costs versus the economic and
-------
intangible benefits. The addition of pumped-storage generation
can contribute a commercial revenue to the multi-purpose scheme
that exceeds the incremental cost of the power features.
Single purpose pumped-storage projects in the U. S. now have a
construction cost of $100 to $I50/kilowatt. The incremental
constructions cost of the pump-turbine installation in a flood
control scheme is about $75/kilowatt. In the case of the Chicago
Regional Plan, about 20% of the cost of the single-purpose, flood
control works could be carried by the hydroelectric generating
plant.
No estimate has been made of the costs or benefits from under-
ground nuclear installation in this type of multi-purpose
development.
INSTITUTIONAL PROBLEMS
It is relatively easy to determine the technical feasibility and
economic value of the addition of generating facilities in a flood
control and pollution abatement scheme. The institutional and
legal aspects create substantial obstacles.
Agencies in charge of flood control and/or sewage treatment do not
usually have the capability nor the legal powers to enter into the
electric power business. On the other hand, the utility companies
have an obligation to meet the growing power demands of their
service area, and cannot rely on the uncertain actions of other
agencies.
Because of costs, it is not feasible for a utility company to
construct an underground pumped-storage project that could serve
for flood control. Agencies empowered to construct underground
flood control reservoirs are dependent upon federal, state and
local legislatures for the funding and timing of their projects.
This makes it most difficult for a utility company to guarantee,
on an equity or purchase basis, that the supplemental pumped-
storage power can be absorbed by the urban electrical system at
a fixed price.
Despite these problems, there are precedents in the U. S. for
mixed public and private cooperation in multi-purpose development.
The successful examples have had the benefit of properly written
legal charters and strong political support.
-------
CONCLUSION
In today's complex society, the many needs of our urban communities
and the possible beneficial developments must be considered from
a multi-functional viewpoint. The theme of this seminar is the
use of our underground urban potential for combined sewer overflow
and flooding problems. Both hydroelectric and nuclear power plants
can be valuable complementary functions.
QUESTION: Did you make any estimate of the amount of heat that could
be dissipated through this underground system?
SORENSON: There would be no heat dissipated as far as the underground
installation itself is concerned. The only way it could be
dissipated is on the surface through such things as cooling
ponds.
QUESTION: Is pumped storage an essential part of the Deep Tunnel Plan
from an economic standpoint?
SORENSON: It is not essential, but it contributes through commercial
revenue and through the large capacity pumps which could
not be considered in a single purpose reservoir.
QUESTION: What is the overall electrical and mechanical efficiency
of the system?
SORENSON: The hydroelectric equipment is very efficient. Turbines
are generally around 90^ and generators around 97%. The
use of energy, taking off-peak energy and converting to
on-peak energy,requires an input of about 1.4 kw-hrs for
every 1.0 kw-hr received. The relationship is the same
for both the hill top and underground storage.
QUESTION: How much could the required nuclear power capacity be re-
duced if this were adopted?
SORENSON They do not replace nuclear plants. The two are comple-
mentary. There is more total energy required in a com-
bination pumped storage with nuclear or fossil fuel plants.
QUESTION: If pumped storage replaced older lass efficient steam
plants, would the overall heat loss still be the same?
SORENSON: There would be an offsetting effect.
QUESTION: Are there any problems involved with using sewage in the
generators?
SORENSON: No, we do not anticipate problems.
-------
RESERVOIR, LAKE, OR
OCEAN
I!\iTAKE
A\'D
DISCHARGE
Construction
Shaft and
Air Vent
Nuclear Plant
Pump-turbine Plant
UNDERGROUND PUMPED-STORAGE
SECTION
(FIGURE I )
-------
}( K
X X 1C. X X
Re servoir
R ese rvoir
Turbines
I i
i i i i i i i i i .
1$ oooo oo_oo <£
Reactors
Condenscr pumps
X X X K H
turbines
with condensers bslow
PUMPED STORAGE- NUCLEAR F>LANTS
LOWER LEVEL PLAN
(FIGURE 2)
-------
IIOOO--
:ooo-|-
o
5
•o
I 9000
o
D.
8000-J-
7000 —
6000-
DAILY LOAD CURVE
August 1974
Pumping
Pumped- Storage
P.--,; king
8 ' ' 16
Time - hours
24
FIGURE 3
-------
12000-
DAILY LOAD CURVE
August 1974
llOOO-r
Pumped- Storage
Energy Economy
« IOOOO--
o
5
o
01
9000--
«£
o
a
8000'
7000-4-
6000
Pumping
16
Time - hours
FIGURE 4
89
-------
LEGEND
Voijmo contained
in Settling Chambers
Overflow to mined
storage area from
settling chambers f\\
'
Total combined sewer overflow
to Deep Tunnel System.
(Total overflow - 3000 acre feet)
72 acre feet overflow to wctorv,cy
Settling chambers volume
Max voliirne-eOOacre feat
Pump , Gon
Max volume - 676O acre feat
Upper reservoir volume
16
October 4
16
October 5
STORM OF OCTOBER 3,1955
(FIGURE 5)
8 16
Ocfofier 6
24
90
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Session 3
EXPERIENCES WITH HARD ROCK TUNNELING AND MECHANICAL MOLES
Moderator - W. T. Painter
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Section 6
EUROPEAN DEVELOPMENT AND EXPERIENCE WITH MECHANICAL
MOLES IN HARD ROCK TUNNELING
by
Pieter Barendsen
Chief Engineer, Product Development
Atlas Copco MCT AB
Stockholm, Sweden
93
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INTRODUCTION
The subject we are dealing with during the first part of this morning's
session - i.e., "European Development etc." - might be construed to
indicate the existence of a certain rivalry in the development of full
face boring equipment between Europe and the US.
A historical review too may contribute towards such an impression. On
24th March, 1853 A. F. Edwards, the man who had planned and estimated
the cost of the Hoosac Railway Tunnel to the last dollar - $1,948,557
no more and no less - reported: "The first model of Wilson's patented
stone-cutting machine for tunnel excavation in rock is now at the
Hoosac Mountain. The result of its working in the natural rock has
been from 14 to 24 in./hr., on a full circle of 24 ft. diameter."
From this he proceeded to line up a detailed working schedule, sub-
stantiated by calculations showing that with two machines one at each
end, the entire excavation would take exactly 1,005 days.
The Wilson machine seems to have driven a total distance of 10 ft.
before being consigned to the scrap-heap, a fate shared by two further
machines, attempting to cut diameters of 17 and 8 ft. respectively, in
the same tunnel. Subsequent events showed that Edwards had gravely
underestimated the technical difficulties in general of this tunnelling
project: Hoosac, with a total length of 24,416 ft., took just under
20 years to complete and the costs totalled some $10 million. And,
while there exists no doubt that out of the Hoosac mess ascended the
American compressed-air industry which took world - leadership in
developing and providing the mining and construction industry with the
early machines and tools for the mechanization of underground rock
excavation work, it is equally clear that technological developments
at that time just had not advanced far enough to create workable full
face boring machinery.
Knowing what we do today about the problems of tunnelling by mole, the
results reached as early as 1884 with Col. Beaumont's 7 ft. diameter
machines - the first to go on record as being successful in hard rock -
are really quite impressive: one of these drove about 115 ft./week in
sandstone in the first Mersey tunnel in England, while the other bored
a total distance of 8,400 ft. in chalk in a pilot tunnel under the
Channel, maintaining an average speed of 50 ft./day for not less than
53 working days at a stretch. The machines worked with kerfing tools
on a rotating head and were powered by compressed air. (Fig. 1)
In the years between 1884 and 1953 a dozen machines were designed and
tested, most of them in Europe, but none of them really progressed
beyond the prototype stage.
All of the manufacturers presently engaged in the full face boring
business - my own firm being one of them - will readily admit that
the US firm of James S. Robbins and Associates did most of the
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pioneering work on the present generation of moles. Development work
began in 1953 and a first machine, still partly equipped with kerfing
tools, was put to work in 1954, reaching an advance of some 10 ft./hr.
in interbedded sandstone, limestone and shale with compressive
strengths of up to 27,000 psi.
Today still, the majority of moles in use are of US design, even if
some of them have been built under license outside this country.
ROCK HARDNESS
Before we investigate in which way modern full face boring develop-
ment in Europe deviates from US praxis, I would like to pause for a
moment and look at the meaning of the term "Hard Rock" which occurs
in the titles of quite a few of the presentations made during these
two days.
According to international contracting practice, all material
occurring within the earth's crust is regarded as rock, if it is so
hard that drilling and blasting or some similar, high-energy process
must be used to break it up.
It has, unfortunately, become customary to relate the rock's hard-
ness - i.e., its resistance to boring - to its compressive strength,
expressed in psi, while a suitable expression for the cohesive
strength of the rock is what is really relevant.
When we consider the values of compressive strength quoted in
literature for some of the more common types of rock (Fig. 2), it
is evident that different rocks vary considerably in hardness and
that considerable spread exists for rocks of the same type.
This not only depends on the fact that there is a large variation
for rock types with the same petrographical designation in different
parts of the world, but also on the actual testing procedure used.
In publications dealing with full face boring we often find one
single maximum value quoted for the compressive strength of the rock,
while nothing is said about how this value was obtained or what
proportion of the total volume of rock is represented by the sample
quoted. This is very unsatisfactory. To compare the "borability"
of different types of rock in a meaningful way the following factors
should be taken into consideration:
1. The compressive and the shear strengths of samples of fresh,
homogeneous and non-fissured rock. The shape and size of the
sample and, in the case of bedded rock, its orientation as well
as the testing procedure, method of preparation, moisture
content, loading rate and number of measurements, should be
regulated internationally or at least be specified for each
individual test.
96
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2. The Mohs' hardness or some other comparative hardness value for the
minerals in the sample, together with the grain size and the
distribution of mineral constituents.
3. Fissures, cleavage planes and other discontinuities in the ranges
of 0.4 to 2.0 in. and 2 to 20 in.
4. The abrasiveness of the rock, expressed by the volumetric
percentage of quartz and felspars, or by a standardized abrasion
test.
5. The porosity of the rock as well as the matrix material between
individual crystals or mineral grains.
In the case of a tunnel driven at great depth, rock pressure should
also be taken into account, as this may be a factor which could make
the rock easier or harder to bore.
In spite of the imperfections of the compressive strength as the sole
yardstick for measuring the borability of a rock, it is widely used,
mainly because it is a value which can be established rapidly from
small samples such as diamond-drilled cores. It would seem to be of
the greatest importance that the authorities responsible for the
design and construction of tunnels and other underground openings
should improve substantially the quantity and the quality of the
information made available at an early stage to those who will have to
carry out the actual excavation. The argument that such pre-tendering
investigations would raise the cost of the completed tunnel is not
valid. On the contrary, the increase in cost would be more than
offset because the contractors would not feel obliged to load their
bids so as to safeguard themselves against the financial consequences
of unknown and unfavourable rock conditions.
For the purpose of further discussion I think that, no matter what
each of us sees as the most important factor to describe "the hard-
ness of the rock," we can agree upon such a definition of "hard rock
tunnelling" that it automatically excludes the use of shields for
the support of unstable or running ground.
DIAMETER RANGES FOR HARD ROCK TUNNELLING MACHINES
As moles usually are designed for specific tunnel diameters, we might
review what range one is nowadays attempting to cover.
As we know, tunnels are driven for many different purposes and with
widely varying cross-sectional areas. (Fig. 3)
Some of them have such small diameters that they should rather be
considered as underground conduits and these are usually constructed
in soil or very soft rock formations by means of augering or tubepressing.
97
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A diameter of 6 ft. must be considered as the lower limit for excavation
by explosives or by means of a full face boring machine operating in-
side the tunnel and most civil engineering experts tend to regard 20 ft.
as the approximate upper limit for economical boring operations under
normal conditions today. Special circumstances, such as the presence
of easily bored, weak rock which would need elaborate support if
blasted or when tunnelling is done close to existing buildings or under
water, have sometimes established their own scale of economic value and
led to the use of machines of some 30 ft. in diameter.
Examples of such very large machines are the Robbins mole used at the
Mangla Dam, later rebuilt and now in use at the second roadway tunnel
underneath the Mersey; the Robbins machine used on the Paris subway and,
more recently, the Robbins mole for the Heitersberg Railway tunnel in
Switzerland and the Wirth two-stage machine (25 and 35 ft. diameter)
for a roadway tunnel near Lucerne in that same country, reaming from a
12 ft. diameter pilot bore.
Generally speaking, one may conclude that within the field from 6 ft.
to 20 ft. diameter the choice of excavation method applied is dependent
on the quality of the rock and economic conditions rather than on the
diameter.
VARIOUS TYPES OF EUROPEAN MOLES
The rock boring machines available for tunnelling in Europe today,
may be divided into two groups, according to the method of operation:
Machines that work the full face of the tunnel at any moment, while
being advanced continuously along the tunnel axis.
This is the type of machine which, in this country, is usually
described by the term "mole". Presently, three manufacturers in
Europe offer this type of equipment: Wirth and Demag in Germany and
Atlas Copco of Sweden through their subsidiary in Switzerland. (Fig. 4)
All of these machines bore tunnels with a circular cross section,
because the cutter-or boring-head is rotated around an axis that
coincides with that of the tunnel itself. Diameters for which
standard machine designs are available more or less "off the shelf,"
range from just under 9 ft. to just over 14 ft. In this respect Europe
seems to follow normal US trends.
Machines with one or more cutter heads of dimensions substantially
smaller than the tunnel cross section which work the face by a
combined rotating and sweeping movement and are advanced stepwise in
the longitudinal direction of the tunnel.(Fig. 5)
Such machines can, because of their design, cut a tunnel of non-
circular cross-section and are, therefore, of special interest in
mining operations where a flat footwall is required for haulage pur-
poses. The majority of these machines are equipped with "pick-
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type" tools and have not been designed to work rock any harder than
the relatively soft formations encou tered in coal mining. Well
known manufacturers in the field are: Mayor & Coulson, Greenside-
McAlpine, Bretby and Dosco in England, Eickhoff and Demag in Germany
and Alpine in Austria. A number of machines for use in soft materials
like coal, gypsum and salt have also been developed in the USSR, from
where they have spread to other countries behind the Iron Curtain.
Recently Atlas Copco have entered this field with designs suitable
for work in hard rock. These machines use the same type of cutters and
cutter heads as are used on the standard machines for circular cross
sections produced by this firm, but in different configurations and
with a different pattern of movement in space.
CUTTING TOOLS
One of the main problems in tunnelling without the use of explosives
lies in the development of tools which, at an economically acceptable
level, are capable of continuous breakage of the rock, resulting in a
fragmentation suitable for a smooth, uninterrupted transportation of
the muck away from the tunnel face.
Tools employed on tunnelling machines have, so far, always been of the
mechanical kind which break up the rock by a crushing and shearing
action. Other methods of rock breaking are possible but, even if some
of them have reached the laboratory testing stage, nearly all of them
are still too "exotic" to be of any practical use in the immediate
future.
One must admit, however, that some highly interesting results are
beginning to be reported from this country on the use of high pressure
water jets for the destruction of rock by erosion, a field pioneered in
Europe (USSR and Great Britain).
Mechanical breakage of rock is effected by inducing stresses exceeding
its compressive/shear strength by loading it with a wedge or cone-
shaped tool until cracks are formed and chips are loosened. In order
to allow the tools to act upon the rock face continuously, they are
commonly shaped as rotating bodies, "roller bits" or "disc cutters,"
spinning freely and mounted on a revolving boring head of tunnel
diameter. (Fig. 6a, b). The thrust of the tools against the face is
generally exerted in a direction which is parallel to the tunnel axis.
The roller bit, which was inherited from the oil industry, is the older
of the two and has so far predominated for work in hard rock. The disc
cutter, because of its generally somewhat lower cost per foot of
tunnel and smaller production of fines, is fast making inroads, even
for work in hard rock like granite and gneiss.
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The rock may also be worked by fixed cutters such as "picks" or
"tips" which are moved along a linear or curved path to cut a groove in
the tunnel face. (Fig. 6c) These tools are usually arranged so that
the main cutting forces occur in a plane at right angles to the tunnel
axis. An important consequence of this arrangement is that machines in
which such tools are employed do not require such high thrusts against
the face as do tunnelling machines in which rotary cutters are used.
Possibly influenced by early experience with cutting or "ripping" tools
in coal mining, many have considered them less suitable than roller
cutters for work in harder rock. During recent years this opinion has
been proved wrong. (Fig. 7)
At the 1968 Tunnelling and Shaft Sinking Conference held in Minneapolis
by the University of Minnesota, Dr. Nevil Cook of South Africa indicated
what requirements of cutting geometry have to be met for the cutting of
hard rock. The fact that these are not purely theoretical observations
has been proved by recent Rock Cutter field tests carried out by the
Chamber of Mines of South Africa in order to arrive at a non-blasting
stopping method for the deep lying gold mines in that country.
Figures are available from Switzerland too which show that this kind of
tool is suitable for the cutting of hard and abrasive rock - a
quartzitic sandstone with a compressive strength varying from 25,500 to
34,000 psi and with a quartz content of not less than 60 per cent -
while the total tool costs for the tunnelling machine in question,
including the cost for renovation of the tool holders, were slightly
below the costs for drill steel, explosives and blasting caps in that
part of the same tunnel which was driven by the conventional method.
(Julia hydro electric power station, 1967/68)
While on the subject of cutting tools, it may be of interest to note
that each of the three European mole manufacturers in the beginning
selected a different kind of tool.
Wirth, starting off with tools manufactured under license to the Hughes
Tool Company, concentrated on roller bits which, for use in harder
rock, were of the TC button type. Some costly experiences when driving
a down grade tunnel in granite in the Austrian Alps led them to a
different design of the cone shape and of the bearing and sealing
arrangements and they subsequently developed and have now standardized
on tools of their own design. Some two years ago they began experiment-
ing with TC studded disc cutters which proved to be more economical
during a 3,500 ft. long raising job at a 60% incline for pen stock
excavation in some hard Swiss granite and gneiss formations last year.
Today they offer both roller bits and disc cutters as standard tools
with interchangeable bearing and saddle arrangements, so that the most
suitable tool may quickly be installed with changing ground conditions.
100
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Demag have always used disc cutters, usually with two or three discs
combined in one bit body. No doubt, our next speaker will go deeper
into this.
The machines now marketed by Atlas Copco, have always used TC tips.
As they, through their cutting geometry, differ substantially from
all other types of tunnelling machines, I will now highlight some of
their features.
SPECIAL FEATURES OF TUNNELLING MACHINES WORKING ON THE UNDERCUTTING
PRINCIPLE
The inventor of the system for cutting rock in a radial direction by
means of a number of separately driven cutter heads equipped with TC
tipped tools, mounted on a slowly revolving boring head of tunnel
diameter, was the late Joseph Wholmeyer, an Austrian engineer, who
took out the first patent as early as 1951, two years, incidentally,
before Robbins started in the tunnelling machine business. The system
was, at one stage, applied by the German firm of Krupp on an experimen-
tal machine for rather soft rock, formations - mudstones of approximate-
ly 3,000 psi compressive strength - and was in accordance with the
original intentions of the inventor, but after his death in 1964,
developed further to make it suitable for the cutting of hard rock,
first by the Swiss firm of Habegger and, since the close of 1968, by
Atlas Copco which firm now owns all the patent, manufacturing and sell-
ing rights.
The reason why it took some 15 years to reach the stage where efficient
and reliable machines could be built according to this principle, is
that it took a long time before the secret was found of how to achieve
acceptable tool economy - namely, that cutting had to be carried out
at low speeds (20 - 50 ft./min.), with considerable cutting depth
(3/8 in. to 3/4 in./tip) and without tool - chatter, thus requiring a
very rigid machine design - and that it took years of research and
testing to develop tough and yet wear resistant grades of tungsten-
carbide.
By inclining the cutter heads to the machine axis and by advancing the
boring head which carries the cutter heads with a speed related exactly
to its rotation, the cutters are caused to penetrate the rock in
concentric, helical paths, cutting the walls of the tunnel like a
multiple-start internal thread. (Fig. 8)
This layout makes it possible to "undercut" the rock so that only
about one-third of the total volume is worked by the cutter tips, while
the remaining two thirds, in the form of an uncut ridge immediately
behind the cut, is broken away by a slight rearward pressure exerted
by a wedge-shaped protrusion behind each cutter tip and rotating with
it. (Fig. 9} Along the tunnel walls the rough surface, produced when
the ridge is broken off, is trimmed by finishing cutters to protrude
not more than 1/8 in. to 1/4 in. above the bottom of the groove cut by
the main tools.
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The radial cutting action requires little thrust against the face and
the forward reaction on the tools when they undercut the rock reduces
it still more. It has been found that undercutting machines need no
more than about 10 to 30 per cent of the thrust required by machines
working the rock with rotary tools. This is a great advantage not
only because it reduces the load on the main bearing, but also because
it decreases the problem of finding sufficient anchorage for the
propulsion unit in soft or broken ground. In addition it simplifies
maintaining alignment of the machine in rock of varying hardness.
The higher the thrust, the greater is the tendency for a boring
machine to veer towards the softer zones. This throws excessively
high side loads on the main bearing and explains why an American-made
tunnelling machine had to be withdrawn with a collapsed main bearing
after boring somewhat less than 600 ft., while an undercutting machine
drove a further 2,900 ft. in the same tunnel and in the same ground
without any such difficulty and without ever being more than 1 1/2 in.
off line. (Julia hydro electric power station, 1967/68)
It must be self-evident that far better tool economy is obtained if
only a third of the total rock volume is cut than when the entire
rock mass excavated from the tunnel is worked by the cutting tools.
The undercutting principle also reduces the production of fines which,
especially in wet tunnels, lead to considerable wear on the muck
removal system through the formation of, often highly abrasive
slurries. Screen-analyses of the muck produced by undercutting
machines in various types of rock show that the fraction below 3/8 in.
constitutes less than 10 per cent of the total volume.
Tunnelling machines in which rotary cutters are employed work the
rock face frontally so that the tools cannot penetrate sideways.
Steering can, therefore, be carried out only by swinging the rear of
the machine around a point close to the tunnel face. Due to the over-
all length of the machine, the minimum curve-radius is usually not
less than 300 to 400 ft.
Undercutting machines work the rock in a radial direction their tools
can penetrate the tunnel walls and steering may, therefore be executed
around a point at an appreciable distance behind the face, leading to
a shorter curve-radius, especially when the machines are built in
articulated sections.
An interesting example in this respect is the machine which Atlas
Copco started up recently at the White Pine Copper mine in Michigan
(Fig. 10).
It can negotiate curves with a radius of no more than 40 ft. to the
centre line and slopes of 20% up or down. The four rotating cutter-
heads of 4 ft. diameter are mounted in groups of two, undercutting
the rock in a sweeping motion, (Fig. 11) like windscreen wipers and,
like them, overlapping in the centre to produce a mainly rectangular
102
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opening, with an absolutely flat footwall and back and slightly
curved sides, of 16 ft. width and 8 1/2 ft. height. These features
make the machine extremely suitable for mining purposes. (Fig. 12)
The machine has been laid out to bore 1,000 ft./month, double
shifting, in the slightly metamorphic, bedded White Pine ore formations
of shales and interbedded sandstones with a compressive strength
between 18,000 and 28,000 psi. Though it is obviously too early to
say, preliminary reports indicate that this target is likely to be
reached from a cutting performance point of view. Due to a series of
up-throw faults, the machine operated with the two lower cutter heads
working in very much harder than normal sandstone underlying the ore
formations when emerging from the erection chamber. Though this
sandstone obviously caused increased tool wear, the cutting speed did
not suffer appreciably.
Another machine for non-circular openings now being built by Atlas
Copco should be of interest to the construction industry for the
excavation of the outer-most branches of sewage and water reticulation
systems, cable ducts etc. under densely populated areas. Weighing no
more than a total of 25 tons and consisting of two main parts of 18
and 15 ft. length respectively which can easily be lowered to tunnel
level through a shaft from street level, the machine will cut open-
ings of 4'3" width and 7'0" height in the centre, with straight,
vertical sides, a slightly dished invert and a semi-circular roof line.
EXPERIENCE OF UNDERCUTTING MACHINES
So far, a total of four machines for circular openings working on the
undercutting principle have been produced and put to work, apart from
the original Wohlmeyer prototype.
Three of the machines, ranging from 12'0" to 13'3" in diameter and
partly manufactured under license in Japan, were used for exploratory
work - pilot tunnels - for the Seikan project in that country, where
a railway tunnel is to be driven to link the main islands of Honshu
and Hokaido. Two of these are at the moment in service and have
driven some 5,000 and 2,000 ft. respectively.
These figures may not seem impressive, but they have been reached
under partly very severe, adverse conditions. Large inflows of water
and extremely bad ground conditions have, for months at a time,
"limited advance to not more than 50 ft./month. I think you will agree
that it would be rather pointless to quote any figures from such a
non-representative job. Let is suffice to say that excavation by
conventional methods would have been completely out of the question
under such conditions.
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The fourth machine has been in service in Switzerland since 1967 and
is now on its second job, excavating an 11'3" diameter sewage tunnel
with a total length of 3 miles near the town of Rorschach.
The rock there consists mainly of a rather tough sandstone, with
compressive strengths ranging from approximately 1?,000 to just over
28,000 psi and containing some 60% of free quartz with a calcitic
binder. For the 9,000 ft. excavated to date the contractor estimated
that the average compressive strength has been in the vicinity of
22,000 psi. During this period the average advance has been 40 ft./
day of 20 working hours. The best day gave 73 ft., the best 5-day
week 250 ft. and the best month 1,050 ft. so far.
Average boring time of the total available working time has been
just over 60% - with some weeks running as high as 75 to 80% - while
tool changes and machine maintenance each accounted for 10% of the
working time. The remaining 20% was lost due to delays behind the
machine. I think these figures tie in pretty well with the average
US results reached on a well-organized construction job.
Tool costs, including costs for renovation and depreciation of the
tool holders and for labour during tool changes, have so far averaged
$10.50 per running foot of tunnel. This amounts to $2.65/cu. yard
excavated. For this kind of rock this must be considered as a very
low figure and is, of course, due to the fact that the tools are under-
cutting and only work 1/3 of the total rock volume excavated.
From the engineer who runs the job down to the old man who sweeps the
floors and makes the coffee, the total crew on site exists of 16 men,
10 on day shift and 6 on night shift. Total cost of the operation,
including transport of the rock out to the tip and with machine depre-
ciation calculated over a total distance of 4 miles, amount to
$57/1inear foot, though you will find it hard to get the contractor to
admit this.
CONCLUSION
Judging from the fact that tunnelling machines working on the under-
cutting principle
-offer a free choice of the shape of the opening produced,
-can negotiate tight curves,
-operate at low thrust and anchoring forces,
-use one type of tool, independent of rock hardness,
-cut the rock with suitable fragmentation at moderate tool costs,
one is inclined to conclude that the undercutting principle enables
us to design very flexible and economical to operate tunnelling
machines.
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Continuous research to improve tool life in really hard rocks,
carried out in close cooperation with tungsten-carbide experts and
other metallurgists, contributes towards making these machines
capable of meeting the widely varying tunnelling requirements of the
mining as well as of the construction industry.
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Quartzite
Compreuive strength
Variations in compressive strength of some rock*
1000
14,200
2000
28,400
3000 4000 5000 6000 kp/cm2
42,700 56,900 71,100 83,300 psilapprox.)
Fig. 2
Diameter m
Hydro-electric tunnels
Cooling water tur-nels
Cable tunnels
Road tunnels
Railway tunnels
Subways
Irrigation tunnels
Sewerage tunnels
Drainage tunnels
Water tunnels
Mines (equivalent dia.)
Storage tunnels
12 3456 78 9 10 11
\
Lower limit for conventional methods and
fnli-far* '-inrinr, __
I I I I
~~^—
I I I I I
MM^BM
I I I I I
h Present limit for economical full-face
borinq?
Fig. 3
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Fig.
Fig. 5
108
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Fig. 6abc
Fig. 7
109
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Fig. 8
b = cutting width
Undercutting towards a free surface
Fig. 9
110
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Fig. 10
Fig. 11
ill
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Fig. 12
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Section 7
EUROPEAN DEVELOPMENT AND EXPERIENCE WITH MECHANICAL
MOLES IN HARD ROCK TUNNELING
Ernst Weber
Managing Director, Mining Machinery Department
Demag Heavy Machinery Equipment
Wolfgang-Reuter-Platz
41, Duisburg, West Germany
113
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PRACTICAL EXPERIENCE IN THE FULLY-MECHANIZED
DRIVING OF GATES, DRIFTS, ROADS AND TUNNELS
GENERAL
At the beginning of my paper I should like to illustrate the extent of
the distances that have to be driven through rock throughout the world.
On the basis of this data one can recognize the importance of fully-
mechanizing the driving of gates, drifts, roads and tunnels.
At the present time the following distances are driven by the West
German hard coal mining industry for an output of some 100 million
tons per year: Approximately 76 mi. of stone drifts and cross cuts
per year, approximately 340 mi. of gates, drifts and roads per year.
This corresponds to a specific driven length of about 4 mi. per million
tons per year.
An estimate of underground mining of all minerals throughout the world
puts the output at not less than 1.9 thousand million tons per year.
The total length of the distances to be driven throughout the world
underground would hence be approximately 1900 x 4.0 mi. = 7,600 mi. per
annum. The civil engineering industry (canalisation, water tunnels and
similar projects) would increase this by about 5%.
It is interesting to compare these figures with statistics obtained
from the South African Mining Industry. During the last 10 years in
that country alone, an average of 630 mi. per year were driven under-
ground. It is safe to assume that the remainder of the world's under-
ground mining industry needs to drive more than 12 times the distance
required by the South African Mining Industry.
The approximate 7,600 mi. per year are driven at a cost of 500 German
Marks for every 3 ft. 3 in. driven ($44/ft.), equivalent to a total
expenditure of at least 6 thousand million German Marks per annum
($1.7 billion/yr). With an average figure of 1 ft. per man and shift,
probably more than 250,000 men are employed all over the world on
underground driving operations (this takes into consideration absen-
teeism, etc.).
It is obvious that these figures illustrating the development of under-
ground tunneling and mining have repeatedly encouraged the investigation
of the possibility of mechanizing tunneling and drifting. A consider-
ation of social aspects is also important. The number of accidents
occurring during conventional tunneling and drifting is radically re-
duced by the employment of fully-mechanized tunneling equipment. Main-
tenance of the health and the ability to work of several thousand
skilled workers underground is to be welcomed from all points of view.
If it is borne in mind that underground mining is taking place at great-
er and greater depths and higher rock formation temperatures are hence
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encountered, it may be seen that mechanization also makes the miner's
work easier.
DEVELOPMENT
As early as 1856 a tunneling machine was used for the first time for a
preliminary investigation of the Channel Tunnel Project. Today, after
more than 100 years of development works, tunneling machines employ
almost the same principle.
During the last 10 years, mechanical tunneling techniques have become
so sophisticated and improved that the economical employment of modern
machinery is beginning to gain ground as compared with conventional
methods. Drifts and tunnels, many miles long, have already been
mechanically driven today, and for most projects, in addition to con-
ventional driving, tenders are also invited for fully-mechanized driving.
It is to be anticipated, that in the near future, developments will
further shift the economic aspects still more in favor of fully-mechan-
ized driving. This trend may be illustrated by a few examples:
The tunnel in the Swabian Jura in South Germany for supplying
water to the Stuttgart area from Lake Constance had a length
of more than 11.6 mi., diameters of 8 ft. 2 in. and 9 ft. 2 in.
and was completely driven in barely three years. Several tun-
neling machines were employed simultaneously at different
points.
Machines with very large diameters have been employed in the
construction of underground railways in large cities through-
out the world such as New York, Budapest, Vienna, Paris,
Munich, Hamburg, Moscow and Leningrad. Partial mechanization
in the construction of the underground railway in Prague,
Czechoslovakia, has already been employed and is being extended.
In the Harz Mountains in the Federal Republic of Germany a
water tunnel about 5 mi. long is presently being driven and
will be completed shortly. Very difficult conditions, such as
hard rock with faults and very high rates of intrusion of water,
were coped with here.
Inclined shafts for power stations were drilled in granite in
the Swiss Alps.
In Japan it is planned to drive hundreds of kilometers of ex-
press tramway tunnels of very large diameter for linking one
island to another.
Beneath various large German towns, sewage tunnels are reg-
ularly driven by tunneling machines. Examples are in Dortmund
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and Wuppertal.
In Liverpool a large road tunnel with a diameter of more
than 10 meters (32 1/2 ft.) was built in the dock area
by a tunneling machine.
Underground caverns are made by full face headers on face
heading machines in hard and soft rock formations.
There is a very wide range of applications in the hard coal
mining industry in Germany. Large tunneling machines are
ready to start work at very great depths in difficult ven-
tilation conditions with emission of methane.
PRACTICAL EXPERIENCE
Past Performances
Figure 1 illustrates some of the performances that have been attained
to date. We have heard of conventional operation in stone drifts and
cross cuts in Czechoslovakia with world record driving rates of 3170
ft./month without linings and supports. Indeed, for a period of 6
months an average of 1846 ft./month were driven.
With a full face header, more than 6160 ft./month have been attained
in the USA in medium-hard rock under favorable geological conditions.
In the Harz Mountains in the so-called Kahleberg sandstone alone with
a compressive strength of about 33,000 psi and containing about 65%
abrasi-ve constituents, more than 10,200 ft. has been driven to date.
Rates of 890 ft./month have been attained. To our knowledge, this is
the first tunnel in the world which is being driven under such condi-
tions and in such hard rock with a tunneling machine.
In Stockholm, 394 ft./month have been attained in granite and gniess
with a compressive strength of about 42,000 psi. This was in almost
exclusively a single-shift operation. The extremely hard rock encoun-
tered here initiated the development of improved drilling tools.
Tunneling machines have also been developed for loosening and cutting
of soft rock. A face heading machine with a soft rock cutting jib,
which works in a totally-enclosed shield, was developed for driving
a sewerage tunnel in England with a length of about 5 mi.
In the inclined shafts in the Swiss Alps, already mentioned, driving
rates of up to 410 ft./month were attained with angles between 30 and
40 degrees. The working conditions, which on a conventional basis
had been difficult, were coped with much more safely by the fully-
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mechanized driving system.
There is now a large number of manufacturers in the world who have
devoted themselves to fully-mechanized tunneling and driving techniques.
I should like to refer to the courage and the development work which
mechanical engineers, contractors and project engineers have applied to
problems of fully-mechanizing the tunneling and heading process. To
our knowledge, in 1969, 25 mi. were already mechanically driven in hard
rock alone. It is not intended at this juncture to give a detailed list
and mention the whole range of types of machine. The relevant literature
and papers in this specialized area have given sufficient information on
this point. I should merely like to point out that all modern driving
processes are based on the principle of operation with roller cutters,
Kerving tools, spirals or cutter bars.
The drilling process is influenced to a decisive degree by the choice
of a suitable tool. The best roller cutter tools have been developed
as a combination of discs of steels highly resistant to wear. Such
discs are combined with cemented carbide plates.
The roller-type tools should produce drillings which are as coarse as
possible and produce optimum advance. However, since the type of rock
changes frequently in practical operations, a compromise must be aimed
at in the selection of tools. A special method of arranging the roller
cutters on the boring head makes it possible to select different dis-
charge widths for the conditions encountered at any time. It is aimed
at developing tools in which the service lives of the bearings and the
elements splitting rock are equally long. The idle times necessary for
exchange are thus substantially reduced. It must be possible to rapidly
remove the roller cutters towards the front by means of transport equip-
ment. Replacement of a roller cutter proper takes only a few minutes.
Figure 2 gives a review of the service life of roller cutter tools as
can be anticipated, to my knowledge, at the present time.
The rate of advance of a machine equipped with roller cutter tools is
a function of the contact pressure on a tool or a function of the
pressure in the hydraulic system. Every type of rock has its own
characteristic phase. When a minimum contact pressure is exceeded, the
rate of advance increases much more quickly. In one case we were able
to establish that between compressive strengths of 36,000 and 42,000
psi, the rate of advance increased by a marked degree from 1 ft. 9 in.
to 2 ft. 7 in./hr. when the pressure was increased from 220 to 280
atmospheres. At this point it is necessary to refer to the wide variety
of factors which, apart from the compressive strength of the rock, also
effect the rate of advance. Such factors include the shear strength,
the degree of intergrowth, the particle size and the proportion of
abrasive constituents such as quartz, felspar and others.
At the present time, on the basis of experience gained regarding the
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service life and the cost of tools, we are attempting to render possible
predictions regarding the costs of future projects. We are aiming at
being able to make such predictions with the aid of regression analysis
from rock data corrections by EDP programming.
A problem particularly affecting the miner is the placing of linings and
supports at the right time. The circular profile represents the most
favorable statical form of cross section. In the event of falls or
formations exerting pressure, it is important to quickly place temporary
supports in the form of sprayed concrete, rock bolts, steel linings or
liner plates.
Figures 3a, 3b and 3c show an example of a modern tunneling machine
which permits the various types of lining and support to be fitted
directly behind the cutting head or behind the front clamping unit.
When a closed ring lining is employed, different types such as bell
sections, "tub" sections, H-sections, liner plates, steel fabricated
mats, W. Hernold System plates, etc. may be employed.
Problems of a special nature arise during driving through zones of
geological disturbance. When soft or slippery zones occure following
hard rock zones, this may mean that driving operations have to be stopped
(when the zones are of some length) because the clamping units do not
find adequate support. In such circumstances it will be necessary to
carry out manual driving in front of the boring head. A conveyor ar-
ranged beneath the machine can be drawn through the head for removal
of the spoil. After linings and supports have been placed the machine
can then pass through the zone of distrubance under its own power.
We have already also driven into tectonically disturbed zones in which
the roof was falling in front of or above the boring head. In this
case the disturbed zone was filled with a quick-curing concrete in-
jected into the rock (Figure 4). After the concrete had set the machine
could be driven through these zones. In some instances this procedure
had to be repeated several times.
When tunnels and other underground gates are being driven, considerable
intrustion of water must be expected from the rock. At the moment, on
a well-known construction site, 38 - 50 USGPM of water are being en-
countered. A large proportion of this occurs in the area of the tun-
neling machine. It has been shown that the mechanical and electrical
engineering of the machine is so reliable that the purely mechanical
functions are not impaired. However, this considerable flow of water
causes a substantial quantity of sludge to be formed. Difficulties
were encountered in removing this sludge. After intensive investigation,
this was taken care of by supplementing the conveyor in the lower area
of the tunneling machine by a special rubber open-top conveyor which
takes care of transporting the sludge upwards to the level of the trans-
fer point to the mine cars. This enabled the rate of advance under
these unusually difficult conditions to be doubled. It may be pointed
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out that all other tests with cyclones, sludge filters or pump systems
were not successful.
Control of Line and Level and Negotiating of Curves
Control of line and level of the tunneling machine by means of a guide
beam generated by a laser has proved entirely successful. It should be
particularly noted that the laser has to be aligned and monitored with
extreme accuracy. Deviations from the set line and level are usually
caused by negligent handling. The authorities responsible for safety
have recently started publishing comprehensive regulations, and to our
knowledge an operating license has always been granted. The object is
to protect the health of men working in the vicinity of the laser. It
should further be noted that the power (1 mW) of the lasers used today
in mechanical tunneling practically eliminate any health hazard. Medical
evidence is available for this.
Control engineers are at present working on fully-automating the opera-
tion of a tunneling machine. Semi-automatic control has already been
proven in actual operation. This eliminates operator faults and hence
prevents consequential damage. In addition, optimum efficiency of the
tunneling machine is obtained. Though it may appear attractive for the
technician to build or operate a fully-automated and remotely-controlled
tunneling machine, this would be associated with the hazard of excessive
liability to operating faults caused by the specific mining difficulties
resulting from high air humidity, poor heat transfer in confined spaces.
Also accessibility would cause difficulties in monitoring such a control
system.
At the present time, when negotiating time, the laser has to be re-
located at short intervals far too frequently. This causes considerable
loss of working time and hence adversely affects utilization of the
tunneling machine. A curve control system should, therefore, be develop-
ed which automatically sets the desired curve radius.
In our experience, negotiation of tight curves is associated with
correspondingly higher tool costs for the outer diameter cutters. It
is, therefore, best to plan as large radii as possible when planning a
route.
Experienced Gained in Removal of Material
The method of transporting material inside and behind a tunneling machine
influences the rate of advance to a decisive extent. On studying the
cycle of operation, it is found that considerable idle times are caused
by faults within this transport system.
Figures 5a, 5b and 5c show in simple form tunneling operations with
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different means of material handling. One essential task of the site
manager of a mechanized tunneling operation is proper organization. The
causes of down-times are to be established and rectified at once by means
of complete and extensive supervision of operation. Down-times during
operation and sometimes even consequential damage can be prevented by
exchange of wearing parts during maintenance times. The degree of utili-
zation of the tunneling machine is improved and an optimum rate of advance
attained.
Climatic Problems
As a rule fully-mechanized tunneling is carried out in an area with extra
ventilation. Design of the ventilation system should be very carefully
planned. Air requirements depend on the number of men at the face. The
volume of fresh air supplied should not be less than about 60 cu. ft.
per man per minute. There should be an additional 90 cu. ft. per minute
per diesel horsepower. In view of possible gas emissions and in the
interest of good mixing of the air in the vicinity, the air speed should
not fall below about 4 in./second. To satisfy these requirements, the
diameter of the ventilation pipe should be large enough to enable the
necessary volume of fresh air to be blown towards the front of the tun-
neling machine. Today it is quite possible to effectively operate an
extra ventilation system even for small diameters over a length of more
than 3 mi.
The heat generated by a tunneling machine should also be taken into con-
sideration. An example of this is a 16 ft. tunneling machine which will
shortly be employed at a depth of about 3100 ft. Cooling equipment with
a rating of more than 350,000 keals per hour has to be installed.
Another measure that has to be taken is the provision of a dust shield
at the front of the machine. By means of water spraying and exhausting
of the dusty air in conjunction with small cyclones or other wet and dry
dust precipitators, the dust content in the area where the operating
personnel are located is reduced to figures which exlude the possibility
of silicosis and meet the official regulations. In this connection it
may be mentioned that in many cases where tunnels are being driven it
was proven unnecessary to have additional dust precipitating equipment
in an apparatus arranged behind the tunneling machine.
Design Features of the Tunneling Machine
One of the duties of the manufacturer of the tunneling machine is to make
provision for its quick assembly and dismanteling. The very cramped
space conditions demand optimum design and dimensioning of the individual
components so that transportation as well as repairs can be carried out
without extra excavation being necessary in the tunnels and in horizontal
and vertical bottlenecks.
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When starting to drive tunnels directly from the surface, it has already
been possible to commission an almost completely assembled machine with-
in one week on a well-prepared site. Between 2 and 6 weeks would prob-
ably be needed, depending on the size of the machine, for delivering and
erecting a machine. Conscientious examination of these transport and
erection aspects must, therefore, be an essential part of any preliminary
calculations.
Tunneling Machines in Soft Rock
A soft rock can be cut or kerved. The experience we have gained is
limited to machines which are of the face heading type. In other words,
one or more jibs fitted with cutter heads carry out selective winning
at the face.
The most favorable employment conditions arise when the rock formation
remains stable until the lining has been placed behind the machine.
Under such conditions maximum rates of advance can be obtained. This,
of course, is subject to the availability of a well functioning organ-
ization such as I mentioned earlier in the case of the machine for
tunneling in hard rock. Face heading machines mounted on crawler tracks
are employed for such conditions. However, their employment is limited
by the angle of inclination of a section in the longitudinal or trans-
verse directions. I, therefore, wish to talk about machines which can
also cope with this difficulty. A technique is employed in which the
machine is hydraulically clamped all round. With the clamping system
it is possible to carry out a course correction or to negotiate curves.
A great deal of experience has been gathered in this area in recent
times. Course corrections can be carried out by up to 6 degrees in
single steps. In undulating rock formations in particular, very frequent
course corrections are necessary, since the seam has to be accurately
and directly followed.
A so-called template control system has proven very good for permitting
a cross section of any form to be driven accurately. This equipment
permits driving operations to be carried out manually or automatically
from the control stand.
In our experience the alternate clamping of the machine may lead to con-
siderable stressing of the rock formation. A so-called "step-moving"
effect occurs. This can also be observed in long wall coal mining when
progressive props are employed. To counteract this, more recent machines
have other types of prop heads. They enable the pressure to be reduced
to very low figures. It is difficult to measure this exactly. Practi-
cal results have shown that the "step-moving" effect is largely elimi-
nated by this means. One such machine of this type for soft rock has
a flat shield which practically consists of single heads of wide area.
The rates of advance attained to date by such a machine in coal are
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about 33 to 50 ft. in one shift of 8 hours. When coal and soft cuttable
subsidiary rock occur together, rates of advance of 25 - 30 ft. can be
obtained in a shift of 8 hours. The consumption of tools for cutting
loose material in the coal seam is about one pick per 3 ft. 3 in. of
advance, equivelant to about 30 - 40 DM/meter ($8-11.00/m). This is
subject to continuous maintenance and checking of the picks.
In the coal mining industry in West Germany, a method of mining has been
tested in which longwall mining is employed with the aid of progressive
props in a downward gradient of 50 degrees. This method of mining en-
courages coal mining engineers to anticipate economic mining of reserves
of coal which are located in steep seams. This means that driving opera-
tions have to be carried out in seams with downward gradient in which the
clamped face heading machines are employed. The first results are prob-
ably to be expected in 1971/1972. In the meantime, experience has been
gained with operation of face-heading machines of shield like design.
Figure 6 shows the design of a machine which will shortly be delivered.
It consists of shields which are connected together in telescope fashion.
The front shield is used for driving, the rear one for clamping. The
machine is to be employed in a rock formation with a strong tendency to
expand, but which is nevertheless easily cut.
Figures 7a and 7b show a quite different version. A face heading machine
mounted on an excavator is intended to enable very large cross sections
to be driven, for instance, for underground railway stations. A machine
such as this can drive a maximum width of 36 ft and a height of 33 ft.
Simultaneous driving with several face heading jibs mounted on a special
frame is also conceivable. No experience is as yet available of this.
Training of Personnel
Driving with fully-mechanized systems and the forms of organization
associated with this require detailed training of skilled personnel at
an early stage. Personnel should, therefore, be intensively trained
for at least 4 weeks before the machine is used for the first time.
Particular attention should be paid to the relevant electrical and hy-
draulic systems as well as to the problems involving surveying.
QUESTIONS OF ECONOMICS
Only a few aspects of this extensive and important area are touched
upon here:
Capital Investment
Figure 8 is intended to give a comparison of capital investment costs for
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equipment for driving tunnels with a cross section of about 175 sq. ft.
Costs
Driving costs are roughly sub-divided as shown in Figure 9. This shows
that fixed costs always have to be assumed for the site equipment, etc.
The variable costs display a logical trend in their relationship, labor,
tools, power, etc. With high rates of advance, the tool costs rise and
the cost of power, capital and labor fall. Moreover, in any calculation,
the indirect costs or savings derived from methods of support resulting
from the fully-mechanized method of driving should not be disregarded.
For instance, the circular, smooth excavation permits the use of a sub-
stantially lighter steel or thinner concrete lining. On one site in
West Germany, for example, the economics of the operation were very
positively influenced as compared with the older method since, on com-
pletion of driving, the lining with steel pipe and concrete backing was
placed much more quickly than had been predicted.
Some specific data may serve to illustrate certain types of cost:
a) The power consumption is about 15 - 20 kwh/35 cu. ft
excavated.
b) The chisel costs as shown in Figure 2 vary widely de-
pending on the type of rock: between about 5. - 100. -
marks/35 cu. ft. ($1.40-$28.00/35 cu. ft.).
c) Depreciation and interest depend on the life. It may
be theoretically assumed that a tunneling machine has
a longer life than 5 years. In the case of a hard-rock
tunneling machine this should be equivelant to a distance
of about 6 - 12 mi -
d) The cost of spare parts average about 5% of the new cost
of the machine per year.
e) Lubricants and water consumption are very minor param-
eters.
CONCLUSION
I have attempted to give you a slight insight into practical experience
in fully-mechanized tunneling. One could, of course, say a great deal
more about each of the problems involved. However, I hope I have suc-
ceeded in creating the impression that the dynamic development in tun-
neling in recent years has led to great success and is a practical
proposition.
Increasing labor costs and the striving towards a higher standard of
living and shorter working week will shift the cost limit between the con-
ventional and mechanical methods of tunneling more and more in favor of
the latter.
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Examples of Headings
Heading
Monthly Headway
Country
Conventional
3.435' (1.047 m)/month max.
average 1.970' (60O m)/month
CSSR
fully mechanized
6.55O' (2.00O m)/month
rock of medium strength
USA
fully mechanized
l.OOO' ( 300 m)/month
o
in sandstone (32.200 psi= 2.40O kp/cm )
(up till now more than 13.200'= 4.0OOm)
Germany
Harz-mountains
fully mechanized
426' (130 m)/month
granite (fine grain sized)-gneis
48.4OO psi= 3.40O kp/cm2 )
Sveden
fully mechanized
inclined shaft
440' (135 m)/month
ingranite (coarse grain sized)
Switzerland
Fig.
IOOC
It 000
2000
2SOOO
3000
'2000
330'
(000
SSOOO fs
'"'•' '''/' Limestone, sandy Shalt
Marl .Shale
•////Diorite. Sjrtnite - and similar
'"' "',Granite, Gneiss
Sandstone (hard) . ^
Fig. 2
12k
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Fig. 3a
Fig. 3b
Fig. 3c
125
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T¥M-G*»trat lorovl
of FvHy-m+ctiomrrd tvttn*
mut*mg bf conrffer
Fig. 5a
126
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•1 i"
o~_.y s" —D '" u u
TVM
GENERAL LAfOUT
Of FULLY-MECHANIZED TUNNELING
Fig. 5b
TfM GENERAL LAYOUT
OF FULLY-MECHANIZED TUNNELING
MUCKING BY BUNKER TffuCKS
Fig. 5c
127
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Fig. 6
i —
•sea/a® tr™**,
Fig. 7a
Fig. 7b
128
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Comparison of Capital Investment Costs
to fit out Tunnel Headings
Heading
Equipment
Capital Investment Costs
Conventional
mucking and site equipment approx. 1.7 Mio DM ( 49O.OOO US
fully mechanized
Tunneling machine approx. 4.0 Mio DM ( 1.150.OOO US
mucking and site equipment
fully mechanized
soft rock tunneling machine approx. 2.5 Mio DM ( 715.OOO US
with shield
mucking and site equipment
Fig. 8
Tunnel Cost
DM/FI
Total Cost
Power.Overhead
& Capitol Charges
Overall Average Advance Rote
Ft/Day
DEMAG
Fig. 9
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Section 8
EXPERIENCE IN EDMONTON CANADA WITH EMPHASIS
ON PNEUMATIC CONVEYANCE OF MUCK
by
C. G. Chrysanthou
Chief Operations Engineer
City of Edmonton Water and Sanitation
Edmonton, Alberta, Canada
Mr. Chrysanthou died in December, 1970. This paper was
prepared from a recording of his oral presentation with-
out the benefit of his editorial review.
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EXPERIENCE IN EDMONTON, CANADA, WITH EMPHASIS ON
PNEUMATIC CONVEYANCE OF MUCK
The City of Edmonton, the capital of the province of Alberta in Canada,
is situated on both sides of the North Saskatchewan River. Edmonton
proper has a population of 460,000 and a surface area of 86 sq. mi. The
Saskatchewan River in Edmonton varies in width from about 400 ft. to
about 600 ft. during flood conditions. The variation in level between
low and high water is about 15 ft., but on the occasions of one or two
extreme floods it has been 30 ft. The flow at low water is about 1200
cfs and at average high water 50,000 cfs. The greater part of the City
lies on a plateau at an elevation 2200 to 2260 ft. above sea level.
There is from 146 to 206 ft. above the river at low water.
The City of Edmonton is built upon surficial deposits of variable thick-
ness underlain by Upper Cretaceous strata. The surficial deposits of
Late Pleistocene age consist of a well sorted pre-glacial sands and
gravels, glacial till and pro-glacial lake deposits in an ascending order.
The bedrock of Edmonton is composed of upper cretaceous shales interbed-
ded with bentonitic shales, sandstone reefs and coal seams.
During the prewar years the majority of the sewage system discharged
directly into the river. Only two small treatment plants of very limit-
ed capacity were in operation. With the sudden and rapid growth of the
City after the war years, it became evident that the two treatment plants
were too small and could not handle the large increase in sewage flow.
The concentration of raw sewage in the river got so high that the oxygen
content of the river was drastically depleted. The conditions got so
bad that some of the municipalities down stream were unable to use the
rive.r as a source of domestic water supply. A firm of consulting engi-
neers was retained to study the problem, and commissioned to design a
sewage system to conform with the new government regulations.
The fact that the water supply is drawn from the river at a point nearly
opposite the center of the City affected the general design and made it
necessary to collect all sewage below this point. The consulting engi-
neer's recommendation was for a major central sewage treatment plant
with an extensive collection system of interceptor tunnels in lieu of a
series of small plants located at various locations with a series of
small lateral collectors. As a result of this recommendation, tunneling
for interceptor sewers was adopted as a major phase of our sewer con-
struction program.
All the tunneling to date has been constructed by City forces. We present-
ly have six tunneling crews working with seven tunneling machines. We
average 5 1/2 mi. of tunnel construction per year in sizes varying from 4
ft. to 21 ft. in diameter with depths varying from 50 to 180 ft.
Except for small lateral columns, which are all hand dug, all our tunnel-
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ling excavation is done with tunneling machines or moles as they are
commonly known in the industry. Our working shafts, are located such
that a minimum of 3000 ft, of tunnel is excavated from each heading;
two headings are worked from each shaft. It is an accepted fact that
the success of any tunneling operation is a direct function of the ma-
terials handling operation. At the last OECD Conference held in
Washington, D.C., materials handling was placed as a second item in
priority in the field of research and development. In tunnel sizes of
10 ft. and upwards this problem is fairly well controlled. The use of
California switches and other switching devices enables us to excavate
at a fairly constant rate. It is in the small diameters where the prob-
lems become critical. Fifty per cent of the tunnel excavation is in the
7 ft. diameter range. It is impossible to install a California switch
behind the machine for this size of tunnel. The cutting of switching
stations in hanging wall is an expensive proposition if the run is short.
Consequently, the only switching of the train is done at the shaft sta-
tion. These limitations cause a considerable loss of excavating time.
Several time studies of the operation as a whole indicated that the mole
was operational for only 43% of the time on a 10-hour shift, the balance
of the time was spent in waiting for the empty trains and installing the
primary liner. Consequently, a new system of material handling had to
be implemented to increase the excavating time of the mole.
At the last symposium on rapid excavation held at Sacramento, Mr. Graham
Ball ofRadmark Engineering (head offices in Portland, Oregon) presented
a paper on pneumatic conveyor systems presently used by Consolidated
Mining & Smelting in Kimberly, British Columbia. The system is used to
back fill cut and fill slopes. We were impressed with the system and
we felt that this may be the solution we were looking for. Consequently,
Radmark and the City of Edmonton agreed to cooperate to test the Radmark's
stowing system as a method of removing materials discharged from a tun-
neling machine.
The pneumatic system was chosen because it should greatly increase the
percentage of time that the tunneling machine can work. As long as a
pneumatic system is designed to handle the maximum discharge from the
mole at the maximum conveyance distance, then the mole should work at
full capacity at all times. By blowing the material directly into a
truck bin, what I call the back stop on the surface, the regular head-
frame and hoist can be eliminated. Access shafts can be reduced in
size. The discharge pipe can be installed into 36 in. diameter holes
spaced on 800 ft. centers along the route of the tunnel. The access
holes are needed for the supply of electric power to the mole as well
as assist in the ventilation of the tunnel. The working area in con-
gested and residential districts is vastly reduced. The pneumatic system
will also assist in the ventilation of the tunnels.
The pneumatic system was first installed in a 7 ft. diameter tunnel. Due
to some difficulties encountered in the installation and operation of the
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system, which I intend to refer to later on in this paper, the system
was removed and installed in a larger diameter tunnel. The system is
presently operational behind a 12 ft. tunneling machine.
The pneumatic system consists of a large volume, low pressure, air blower
installed in a closed-in trailer positioned at the surface of the shaft
head. The air is piped to the stowerthrough a 12 in. diameter quick
coupled pipe. The Radmark feeder or stower is connected to the mole by
means of a draw bar, A hopper is located directly under the discharge
conveyor from the mole. Two telescopes have been provided behind the
stower, one for the air pipe and one for the materials handling pipe to
permit the blower to travel forward with the mole. When the excavation
has advanced 10 ft., the telescopes are fully extended and the stower is
shut down. The telescopes are then retracted, a 10 ft. length of pipe
is coupled into each line, and the excavation proceeds. The controls
for the surface blower are located on the stower control panel under-
ground and the over load protection will automatically shut down the
pneumatic system in the event of any blockages. The materials handling
ptpe is a 10 in, cast iron pipe with an internal surface hardened to a
hardness of 630 Brinell. An overhead monorail is continually extended
to supply all the necessary construction materials to the face.
At this point Mr. Chrysanthou showed a film of the pneumatic system in
operation. This prompted the following discussion.
QUESTION: What is the maximum size you are striving for there?
CHRYSANTHOU: We pass 3 1/2 in. size particles.
QUESTION:
CHRYSANTHOU:
QUESTION:
CHRYSANTHOU:
QUESTION:
CHRYSANTHOU:
QUESTION:
CHRYSANTHOU:
QUESTION
Have you used it long enough to get any idea on pipe cost
or wear?
No.
Why couldn't you drop it into a hopper and blow directly
out of a hopper?
Yes, we have done that too. This is basically what you
have to do when you go into a residential district, you
can't blow.
What is the total distance of the pipe from your machine
to the top?
About 450 ft.
What is the maximum that you can go?
We propose to go 800 ft. laterally and 150 ft. up.
What is the consumption of the compressed air for 100 cu.
-------
yds?
CHRYSANTHOU: I don't think I can give you that detailed information, but
the blower has a capacity of 5800 cfm at 18 psi. It is
powered by a 500 hp motor.
Our comments on the system so far are that the basic idea of the stower
following the mole is good. The capacity of the pneumatic system is
adequate and will not restrict the boring rate of the mole. The stower
is capable of handling 3 1/2 in. material and larger sizes are broken
down to size by chopping. The equipment can be operated by tunnel labor-
ers. The abrasion factor of the material is low, so pipe and elbow wear
should not be a problem. Because of the dampness of the material, dust
is not a problem.
In the initial installation of the pneumatic system in a 7 ft. diameter
tunnel, the small diameter of the tunnel compounded vnth the fact that
the tunnel was started on a curve caused various inconveniences to creep
up. The lack of working space make it awkward and frustrating for men
to work efficiently. The system provided for carrying the telescopes
behind the stower was designed for straight tunnels. The telescope skid
could not center itself in the tunnel, therefore, it tended to climb up
the ribs and not remain under the telescope. Only one ball joint was
supplied and this was located at the back of the stower. The operators
had a difficult time lining up pipe joints when a section of the pipe
was to be added to the telescope. The materials handling pipe was too
rigid and we had difficulty in forming it to the radius of the tunnel.
The air pipe could not be located over the material pipe. It, there-
fore, lay on a radius different than that of the material handling pipe.
Joints in this pipe would get ahead of the joints in the material handl-
ing pipe and, therefore, pipes spools of different lengths were required
in the air pipe.
The pneumatic system bogged down when large sizes of material were fed
to it. The presence of these large pieces could not be avoided and the
balance of the material bridged in the hopper. This necessitated the
shutting down of the feeder and manual removal of the bridged material.
A second set of choppers was installed to break down the large pieces;
thought it did help some, it was soon discovered that a larger, faster
and more powerful unit was required in order to keep up with the dis-
charge rate of the mole conveyor. A build-up developed in the elbows.
As this build-up increased, the operating pressure increased. The back
pressure was high enough at times to activate the automatic shut-off.
No cleanouts were provided for the elbows and, since the build-up was
very high, a lot of time was consumed in dismounting and cleaning the
elbows.
The pneumatic system handled the shales and the stiff clay but complete-
ly broke down when a pocket of quicksand was encountered. The water in
135
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the formation would mix with the clays and turn the clay into a stickey
mess that would instantly clog the materials handling pipe and the el-
bows. It was at this stage that a decision was made to remove the unit
and return to the conventional materials handling method.
You may at this point feel that I have painted a fairly dark picture of
the pneumatic system. This is not the case. We did not expect any
miracles from any untried system right off the start. We undertook the
use of the pneumatic system as a research project. Since it is to my
knowledge a first of its kind in that particular application, we felt
that the condition should be presented to you exactly as it happened.
The system was reinstalled in a 12 ft, diameter tunnel. Our test holes
indicated that the tunnel would be excavated in a continuous shale for-
mation. Prior to putting the system in operation, the, following modifi-
cations were made:
1. A second ball joint was added to the end of the telescopes.
This enabled the materials handling pipe to better main-
tain its alignment.
2. On a curved portion of the tunnel, a five degree miter-
bend was added at every second joint of the materials
pipe.
We are now considering the use of ball joints at every second joint of
the materials handling pipe. These would be of value even in straight
tunnels.
A second telescope will be added to the air pipe line. This could be
adjusted to keep the flanges of the main telescope side by side. The
pipe installation procedure would be speeded up fay changing both pipes
at the same time. Mark II type elbows were installed. The elbows are
fitted with clean-outs for easy access and inspection. The hopper on
the stower has been enlarged and a more substantial set of choppers in-
stalled. The movie that you saw was after the innovations were put in
it, except for the chopper. The choppers will be capable of handling
the large pieces as fast as they are discharged from the mole con-
veyor, thus, drastically eliminating any chances of bridging in the
hopper. We are also seriously thinking of putting in a vibrating
grizzly at the top of the hopper that would feed into a small jaw crush-
er attached inside the hopper. This would take care of the large pieces
of sandstone and hard material. The throat of the stower was enlarged
to allow larger materials to pass.
The present application of the pneumatic system is working satisfactor-
ily. Last week we had the best day of the pneumatic system in a 12 ft.
tunnel. We reached 55 ft. in 20 hrs. in two 10-hour shifts. There
were quite a few breakdowns and quite a few revisions to be made, but
it was the best day we made so far. Nevertheless, we still consider it
136
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to be a research project with room for improvement. There is no
doubt in our minds, that some further changes will be made before we
are completely satisfied.
In conclusion, may I say that the pneumatic conveyance system has its
limitations, in the art of softwork tunneling. It should not be con-
sidered if there is any chance of encountering wet clays or quicksand
in the course of the excavation. The application of the pneumatic
system is limited by the diameter of the tunnel. Where switching sys-
tems and double tracks can be installed, the conventional method of
materials handling is still more economical. In our opinion, the sys-
tem can best be used in a hard rock formation trailing a hard rock
machine. The pneumatic system is ideally suited for free flowing ma-
terials such as rock cuttings , gravel or sandstone. The nearly uniform
size of the materials excavated by the hard rock machine would eliminate
any feeding problems. Though an abrasing problem may develop, the ma-
terial should be more predictable and easier to adapt to.
QUESTION:
CHRYSANTHOU
QUESTION:
CHRYSANTHOU:
QUESTION:
CHRYSANTHOU:
QUESTION:
CHRYSANTHOU;
QUESTION:
CHRYSANTHOU:
What about the noise on the surface from the blower?
The blower is installed in a semi-trailer, a closed--in
unit, and the walls of the1trailer are insulated with 4
in. fiber-glass bat insulation. Really the noise problem
is in the range of 75 decibels which is still within 15
decibels below our noise law.
What about dust at the chopper?
We have no trouble with dust at the chopper. We have
dust at the top at the bin after the material has been
broken down in the pipe during conveyance.
Is the tunnel pressurized?
No, we never pressurize.
Where is the pressure applied?
Well it's fed at the bottom to the stower and the stower
is, if you can picture it, a paddle wheel rotating at 40
rpm. The material will drop into it and all the paddle
wheel will do is feed it into the line where the air is
coming in from the blower.
What pressure do you use in there?
Our maximum is 18 psi, but we are working with about 8
or 9 psi right now.
137
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QUESTION: Did you investigate other kinds of pipe?
CHRYSANTKOU: We entered into a covenant to purchase that material from
Ragmar Engineering under rental-to-purchase basis. This
meant that they had the right to set the pipe and the
equipment on the job. The pipe is made in West Germany.
It's made by Essen and to date has been an excellent pur-
chase, an excellent choice.
QUESTION: You mention your best day using this method was 55 ft. How
does that compare to your normal progress?
CHRYSANTHOU:
QUESTION:
CHRYSANTHOU;
QUESTION:
CHRYSANTHOU:
QUESTION:
CHRYSANTHOU:
QUESTION:
CHRYSANTHOU:
QUESTION:
CHRYSANTHOU:
It's about 15 ft. less.
Have you experimented with the smaller size pipe than the
10 in.?
No This has been our first application. Of course, as
you know, that the diameter of the pipe is a function of
the size of the material that you're going to carry through
it, the velocity its going to travel through it, and the
air it should take. Ten in. happened to be in our calcu-
lations, the minimum size we could use in this type of ap-
plication.
Is the air completely contained from the time it goes in
till the time it comes back out?
Yes sir.
What are the abrasive characteristics of Edmonton formation
compared, for exampled, to the limestone that we have in
the Chicago area?
I don't think it compares. I think that our abrasive fac-
tor is very very low down there with our shales. We have
never tested it, but we know that the life of our tungsten
carbite bits is quite high; so really we don't have an
abrasion problem there at all.
I'm interested in the comment that you're doing this work
with about six of your own crews headed by a force account.
That's a loaded question.
count?
What do you mean by force ac-
In other words, your not bidding the job.
Well, let's put it this way. We put an estimate in and
everybody is willing to take a crack at it if he wants to
138
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QUESTION:
CHRYSANTHOU:
QUESTION:
CHRYSANTHOU:
QUESTION:
CHRYSANTHOU:
QUESTION;
CHRYSANTHOU:
QUESTION:
CHRYSANTHOU:
I think we have a lot of contractors here. To do them
justice I should explain to them that in 1955, when we
started initiating this program of sewer construction,
we set the first tunnel to tender. Of courses not having
any contractors that were experienced in tunneling in
Edmonton at the time, they went into joint ventures with
some of the American contractors. The price was so ex-
orbitant for an 8 ft. diameter tunnel that we felt that
we could do the job ourselves and write off the capital
investment against one project, which we did. Then we
kept on growing and growing till it's too late to get
out. But, basically as a member of a form of government
I'll tell you that my primary interest is to get the
cheapest price I can get for the City of Edmonton. Now
whether I do the job, or whether a contractor does it is
immaterial and irrelevant. As long as he can prove to
me that he can do it cheaper, more power to him.
There's another part of this question. What kind of help
are you using to run the machines? In other words, are
you using operating engineers, hoisting engineers or la-
borers?
No. Our system in Canada is a little different than
yours is. An employee who works for a municipal govern-
ment in Edmonton joins a union that's called the Canadian
Union of Public Employees. You have your welders, me-
chanics and tunnel diggers, maintenance workers, sewer
maintenance workers and the fellow that cuts the grass
in the park. The are all lumped in one union. It makes
it easier to deal with, a lot easier.
Is there a patent on any of the features of the pneumatic
system?
I think that you would have to get in touch with Ragmar
Engineering in Portland. I couldn't answer that.
Does the air come from the compressor or a blower?
The blower.
What was the removal rate of the material?
About 200 tons an hour.
How many miles of tunnel have you dug since 1955?
I must have about 160 mi. under my belt now.
139
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Section 9
GEOLOGIC EXPLORATION FOR CHICAGOLAND AND OTHER DEEP ROCK
TUNNELS TO BE CONSTRUCTED BY MECHANICAL MOLES
by
George Heim
Project Geologist
Dames & Moore
1550 Northwest Highway
Park Ridge, Illinois 60068
R.W. Mossman
Assistant Vice President
&
Homer W. Lawrence
Geophysical Section Manager,
Well-logging Division
Seismograph Service Corporation
Tulsa, Oklahoma
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GEOLOGICAL EXPLORATION FOR THE CHICAGOLAND
DEEP TUNNEL PROJECT AND OTHER ROCK TUNNELS TO BE
CONSTRUCTED BY MECHANICAL MOLE
PURPOSE AND SCOPE
The Chicagoland Deep Tunnel Project of the Metropolitan Sanitary
District of Greater Chicago was proposed as a method to reduce
flooding and pollution caused by the overflow of the combined
sanitary and storm water sewer system during periods of heavy
rainfall. The details of the Deep Tunnel Project are discussed
in the papers included in these proceedings by Keifer, Koelzer,
and Neil.
In general, as shown in Fig. 1, the Deep Tunnel concept consists
of interception of the combined sanitary and storm water overflow
at the overflow points, conveyance of the overflow water in
tunnels to a mined room and pillar type storage area from which
the overflow water can be pumped at a reduced rate to permit
treatment of all waste water. As an added feature, water can
be stored in a surface reservoir and released to the lower res-
ervoir to provide the capability of peak power generation.
The purpose of this paper is to describe the subsurface geological
exploration program performed in 1967 and 1968 for the Chicago-
land Deep Tunnel Project. This program illustrates the type
and magnitude of exploration performed to demonstrate the technical
feasibility of the project.
The Deep Tunnel Project was divided into the Master Plan area
and the First Construction Zone as shown in Fig. 2. The Master
Plan Area included the total project area and the First Construction
Zone was the first area being considered for actual construction.
The papers by Keifer and Neil present later modification to the
original construction plan.
GEOLOGIC CRITERIA
The geologic criteria required for the Deep Tunnel Project as
set forth in earlier planning studies included the following:
1. Rock strata of adequate thickness for the tunnels or
the mined storage area.
2. Rock capable of providing long term stability with a
minimum of supports.
14-3
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3. Uniform rock characteristics which are desirable for
excavation by mechanical moles.
4. A minimum of water problems from groundwater inflow.
5. Protection of the groundwater resources from contamination
which could be caused by outward seepage of the storm
water from the tunnels or the mined storage reservoir.
GEOLOGIC SETTING
The First Construction Zone is located on the east flank of a broad
structural arch known as the Kankakee Arch. This arch separates
the Illinois and Michigan structural basins. Because of erosion
along the crest of the arch, some of the strata present in
eastern Cook County are absent farther west. The eastward dip
of the strata on the eastern side of the arch in the Chicagoland
area is generally 15 to 25 ft. per mile. Superimposed on the
regional dip are a series of secondary folds whose axes trend
approximately east-west.
The substantiated faulting in the Chicagoland area is believed to
have occurred after the deposition of the Silurian strata. Pre-
viously reported faults include: the Sandwich fault zone, near
Joliet which trends southeast and has a displacement over 1,000 ft.;
a complexly faulted area at Des Plaines, Illinois; and several small
northeast trending faults reported in Chicago Avenue water supply
tunnel constructed in the late 1920's and early 1930's. In the
First Construction Zone several faults have been interpreted on
the maps prepared by Seismograph Service Corporation.
The strata in the First Construction Zone consists of both soil
and rock deposits. The soil deposits are made up of artificial
fill and Pleistocene age deposits of lacustrine clays and sands,
glacial till, and outwash sands and gravels. The rock strata
are made up of a thick sequence of Silurian, Ordovician, and
Cambrian Age sediments consisting of dolomites, shales, and
sandstones. The deposition of the sedimentary strata was inter-
rupted at various times and several erosional unconformities are
present.
SUBSURFACE EXPLORATION PROGRAM
PURPOSE
A four phase subsurface exploration program was performed to
demonstrate the technical feasibility of the Chicagoland Deep
-------
Tunnel Project. The exploration program included seismic surveying,
geophysical borehole logging, test drilling and laboratory testing,
and groundwater drilling and testing. Seismic surveying and geo-
physical borehole logging were performed in the Master Plan Area
and all four phases of exploration were performed in the First
Construction Zone.
SEISMIC SURVEY
PURPOSE
The seismic survey was performed (1) to establish the bedrock
topography, (2) to establish the configuration of the top of the
Galena Group, and (3) to locate potential faults.
SCOPE
The seismic survey was laid out on a basic 4 mile grid spacing
in the Master Plan Area and on a basic 2 mile east-west spacing
and 4 mile north-south spacing in the First Construction Zone. Minor
modification in the basic layout was made to accomodate variations
in the city street system and to obtain more detail in subsurface
information in certain areas. The location of seismic lines is
shown on Fig. 3.
Approximately 420 miles of seismic traverses were made during the
periods of November, 1967 to March, 1968 and May, 1968 to June, 1968.
FIELD METHODS
Seismic exploration methods have been used for many years to de-
termine subsurface rock conditions and attitudes. These techniques
have largely been confined to the search for oil or to measurement
of the earth's crustal structure on a continental basis. The method
rarely has been applied to construction problems on a broad scale.
There are two variations of seismic surveying techniques based
on physical phenomena common to the physics of wave motion: the
refraction and reflection methods. Fig. 4 and 5 provide diagrammatic
illustration of the two diverse techniques. Both utilize a
controlled source of energy and measure the travel time through
the rock layers to suitable receptors on the surface. The travel
times can be converted to depth measurements, and the configuration
of the surface of a stratum can be interpreted by contouring.
-------
In the refraction method, travel times are measured for energy
transmitted through the rock layers for an extended horizontal
distance as compared to the vertical components of its path.
In the reflection method, near vertical travel of the energy
is measured as it is reflected from various subsurface rock layers
back to the surface. Specific reflective interfaces occur where
adjacent rock layers exhibit dissimilar acoustic properties.
In the Chicagoland area, it was desired to map the bedrock surface
and the attitude and continuity of the deeper Galena-Platteville
strata. The shallow depths to bedrock, generally less than 150 ft.,
suggested the refraction technique as the most efficient means of
obtaining the near-surface information. Since the relative acoustic
velocities made it virtually impossible to secure information from
the deeper rock layers by refraction means, the reflection method
was employed for these measurements.
Because of the intense cultural development in the Chicagoland
area, the use of explosives for an energy source was not acceptable.
Therefore, the Vibroseis* method of seismic exploration, which
has features that particularly adapt it to use in an urban en-
vironment, was selected. The Vibroseis system consists of re-
cording energy from a vibratory source and subsequently applying
correlation methods to reduce the data to geologically inter-
pretable results. The truck-mounted vibrators (Fig. 6) introduced
a signal of several seconds duration into the earth. The seismic
signal has frequency characteristics which vary progressively over
a predetermined range. Knowledge of the form of this input signal
enables extraction of the signal from a background of very high
ambient noise when processing the recorded data. In the Chicago-
land area, random noise of considerable magnitude was generated
by vehicular traffic and industrial operation. Nevertheless,
the Vibroseis system permitted operations to be conducted in day-
light hours, with consequent improvement in efficiency. During
peak traffic conditions, where the presence of the equipment and
personnel on the principal thoroughfares would have contributed
to traffic congestion, work was suspended. The Vibroseis signals
had an additional attribute in that they in no way disturbed
persons or structures in the vicinity.
Two Vibroseis field crews were utilized simultaneously to conduct
most of the investigation. Each field crew was comprised of:
three truck-mounted vibrator units which operated in synchrony,
truck-mounted electronic instrumentation for receiving and
recording the seismic signals; and service vehicles to handle the
*Trademark and service mark of the Continental Oil Company
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positioning of individual detectors and their connecting cables,
for the maintenance of equipment, and for the transportation of
personnel. Radio communication was maintained between the various
units involved in the operation.
DATA PROCESSING
A flow diagram illustrating the acquisition and processing of
the seismic data is shown in Fig. 7. The management of the
operation, the initial processing of the data, and the preliminary
interpretation of the results were handled from a centrally located
project headquarters in Elmhurst, Illinois. The individual crew
offices were maintained in the immediate area of operations and
were moved from time to time to minimize non-productive travel
time. Final processing and interpretation of the information
was done utilizing digital computing equipment and facilities
at the contractor's plant in Tulsa, Oklahoma.
Seismic cross sections were prepared in terms of travel time and
were then subjected to interpretational evaluation to establish
identification of the geologic horizons represented by the re-
flections, and to determine lithologic continuity and location of
zones of possible faulting associated therewith.
The final stage of the interpretive process consisted of con-
version of the various time measurements to depth values and
the subsequent display of this information on digitally plotted
depth cross sections and on contoured maps. To perform this con-
version, knowledge of the speed of travel of the energy through
the various rock layers was necessary. Such velocity information
was obtained by comparison of the seismic data with geophysical
borehole information obtained from water wells adjacent to the
lines of seismic traverse and from deep holes drilled speci-
fically for the Deep Tunnel Project. Direct borehole velocity
measurements were made in one test hole to provide positive
confirmation of the identification of the reflecting horizons.
The velocities established for the various rock units are shown
on Fig. 8.
RESULTS
Good correlation was obtained between the seismic data and the
horizon tops reported in most of the wells. However, for each
horizon mapped, the velocity through the overlying material was
found to vary across the area on a geographic basis. Consequently,
iso-velocity maps were prepared for each seismic event mapped,
and each seismic time datum value was converted to a depth re-
lative to sea level according to the appropriate velocity for its
geographic location, before being placed on the graphic displays.
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The results of the seismic survey were presented in the form of con-
tour maps and cross sections. The maps are based on all available
borehole data and on the calculated seismic depths. They include (1)
the top of rock, [2.) the top of the Galena Group, C3) a partial inter-
pretation of the top of the Ancell Group, and (4) an isopach map of
the interval between the top of rock and the top of the Galena Group.
The top of rock and the top of the Galena were of primary importance
in this study and the discussion is limited to these surfaces.
Cross section based on continuous seismic depth calculations were made
for each seismic traverse. The cross sections show (1) the ground
surface, (2) the top of rock, (3) the top of the Galena Group, (4)
the top of the Ancell Group where obtained, and (5) at a few locations,
the top of an unidentified Cambrian Age formation.
Top of Rock. The bedrock in the Chicago area is overlain by a variety
of materials including: man-made fills; glacial deposits of till and
outwash sands and gravels; and lacustrine deposits of sands, silts and
clays.
The bedrock surface is the result of a complex geologic history which
included folding, faulting and erosion. The erosional history had
the dominant affect on the bedrock surface and, therefore, it is not
possible to clearly define folds or faults.
The complexity of the soil deposits which overlie the bedrock, the
complex nature of the bedrock surface, and the shallow depth of the
bedrock were major problems which had to be considered in the seismic
interpretation. The resulting contour maps depicting the bedrock
topography are believed to present an interpreation with the probable
error not greater than+10 ft. where the seismic data are recorded.
Top of Galena. The configuration of the top of the Galena Group is
the result of folding and faulting. The interpretation of this surface
in the First Construction Zone is shown on Fig. 9. The accuracy of
this interpretation is believed to be+_25 ft. where the seismic data
are recorded. The regional dip is to the east, but a series of minor
folds are superimposed on the regional dip making the Galena surface
somewhat more complex.
The seismic data indicates the possibility of nine faults which cut
the top of the Galena in the First Construction Zone (Fig. 9). The
calculated displacement along these faults ranges from less than 10 ft.
to as much as 55 ft.
Seismic exploration is an indirect method of exploration and the faults
shown on Fig. 9 have not been substantiated by direct exploration meth-
ods. It is believed, however, that the seismic surveys will detect
all potential faults having vertical displacements of 20 ft. or more and
in some instances will detect those with displacements as low as 10 ft.
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Therefore, the method is valuable to locate potential faults, but their
actual presence must be substantiated by direct subsurface exploration
techniques.
GEOPHYSICAL BOREHOLE LOGGING
PURPOSE
The broad purposes of the geophysical borehole logging program were
twofold: (1) to establish the geophysical characteristics of the
stratigraphic units and (2) to determine the variations in the rock
characteristics of each of the stratigraphic units. The logging tools
selected for use on this project were chosen for specific purposes
within this broad framework. Logs were required which would (a) supply
correlations from hole to hole, (b) define certain rock properties such
as: porosity, fluid content and movement, and engineering character-
istics such as density and the elastic moduli and, (c) log data which
would supplement and corroborate the seismic data.
SCOPE
A total of 41 boreholes were logged geophysically. Of these, 11 were
existing wells in the area which were logged to provide a wider distri-
bution of stratigraphic data, 19 were rock holes drilled and cored for
the Deep Tunnel Project, 10 were ground water test holes drilled, but
not cored for the Deep Tunnel Project, and 1 soil exploratory hole
drilled in the upper reservoir area.
LOGGING TOOLS AND METHODS
The logging program included the following logs: Gamma Ray, Neutron,
Formation Density, 3-D Velocity, Temperature and Caliper.
Gamma Ray Log. Gamma Ray logs measure the natural radioactivity pres-
ent in rocks in fluid-filled and dry holes, whether open or cased.
Shales normally contain more of the three most commonly occurring
radioactive elements (uranium,potassium and thorium) than do other
sedimentary rocks, so the Gamma Ray log may be considered as a shale
identifying log. Use of the log permits evaluation of the shaliness
of limestones, dolomites, and sandstones. The Gamma Ray log is sen-
sitive to hole enlargement, the presence of casing and of borehole
fluid. The effect of all of these conditions, however, can be corrected,
Neutron Log. The Neutron log measures the amount of hydrogen contained
in rocks. The hydrogen content is directly related to porosity so the
Neutron log becomes a porosity measuring device. The Neutron probe
contains a source which continuously bombards the rock formation'with
-------
a cloud of high energy neutrons. These neutrons collide with nuclei of
matter in the borehole and surrounding formation and are ultimately
captured. If they collide with heavy atoms of elements like silicon,
aluminum, iron, calcium and oxygen, they will be reflected elastically
without much loss of energy. If they collide with light hydrogen atoms,
which have almost the same mass as neutrons, their energy will be
greatly reduced. When the energy is reduced to a certain level by con-
tinued collisions, the neutron is captured and gamma rays of capture
are emitted. These gamma rays of capture are measured by a detector
spaced at a fixed distance from the source. Where hydrogen is confined
to water present in pores, the Neutron log then measures porosity.
Shale also contains an abundance of hydrogen as combined water. The
Gamma Ray log may be used to correct the shale influence on the Neutron
log. Hole enlargement, casing, or a change in fluid content in the
borehole will affect the Neutron log, but again, these are all conditions
for which correction can be made.
Formation Density Log. The Formation Density log measures the bulk
density of rock. The probe in this tool contains a gamma ray source
which continuously emits gamma rays into the borehole wall. The
emitted rays bounce off electrons and the intensity of the reflected
rays as seen by a detector in the probe is dependent upon the electron
density. Electron density is directly proportional to the bulk density
of all rocks of interest here. The density log is another porosity tool,
and density is one of the factors used in combination with velocity data
to compute the elastic moduli.
3-D Velocity Log. The 3-D Velocity Log measures the transmission time
of sonic energy in both the compressional and transverse modes through
the rock surrounding a borehole. The logging probe consists of magne-
tostrictive transmitter which is pulsed approximately 20 times per
second as the probe is moved upward in the hole. The pulse energy moves
outward through the borehole fluid and at the borehole face is refracted
and travels in the rock media. It is detected as it moves past the re-
ceiver. The various modes of signal travel, which propagate at dif-
ferent velocities, are recorded as a variable intensity display. Fig.
10 show a ection of a 3-D Velocity log with the pressure, shear, and
bounda:y w e arrivals indicated.
The 3-D • /locity log supplies the basic data for the computation of the
engineering properties of rocks: bulk, shear, and Young's moduli, and
Poisson's ratio. Since it measures compressional wave velocity, it is
also useful in converting seismic survey time data to depths. The
seismic system is dependent on velocity and/or density changes at which
reflection of the input energy may occur. The velocity and density
logs both show graphically the interfaces which should reflect energy.
The 3-D logger is sensitive to changes in borehole diameter and can
only be used in fluid-filled holes.
150
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Temperature Log. The temperature Log measures the temperature in
fluid-fined and dry holes, and in open or cased holes. The downhole
probe contains a sensitive, quick-reacting thermistor. Under normal
increases with depth in accord with the geothermal gradient existing
in the area. When the temperature curve deviates from the normal
gradient, it indicates a zone in which fluid is entering or leaving
the hole and the approximate volume of flow.
Caliper Log. The Caliper Log is used to supply a record of changes in
borehole diameter primarily for use in interpreting other logs which
are sensitive to such changes. There are several types of calipering
devices, but the most commonly used has 3 pencil-like arms at 120°
lateral separation. These measuring arms are able to detect small,
thin changes such as washed out shale laminations.
All of the foregoing logs are run from a unit as shown in Fig. 11.
Hoisting equipment and cable reels occupy approximately half the cab
space, while the other half houses the signal processing equipment and
recorders.
RESULTS
An example of the geophysical borehole logging results is shown in Fig.
12. The Joliet Formation and the Guttenberg Formation were found to
be two geophysical marker beds in the Chicago area. The Racine Forma-
tion was found to be a variable dolomite, the Joliet Formation a fair-
ly uniform dolomite, the Kankakee Formation has numerous shale partings,
the Brainard Formation is a fairly uniform shale, the Fort Atkinson
Formation is a fairly uniform dolomite, the Scales Formation is a fairly
uniform shale, and the formations in the Galena and Platteville Groups
are fairly uniform dolomites.
Borehole logging results from the cored holes were used (1) to cor-
relate the stratigraphy from cored holes to the previously existing
boreholes which were geophysically logged during this project, and (2)
to establish the stratigraphy in the ground water test holes so packers
could be set to isolate hydrologic units.
TEST DRILLING
PURPOSE
The purpose of the rock core drilling program was (1) to provide cores
from which the rock characteristics of the various strata could be
evaluated so the most favorable elvations could be selected, (2)^to
provide positive stratigraphic control in key areas, (3) to provide
core for correlation with the geophysical borehole logs, and (4) to
151
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provide boreholes in which the water bearing properties of the rock
could be evaluated and monitored.
SCOPE
Twenty-four core holes with a total footage of 34,360 ft. were drilled
during the period from November, 1967 to March, 1968. The deepest hole,
having a total depth of 1,696 ft., was drilled to the upper portion of
the Eau Claire Formation.
FIELD METHODS
All rock, core holes were drilled with wireline equipment and excellent
results were obtained. Water pressure tests were run in all core holes
to evaluate the water bearing characteristics of the rock strata. All
the boreholes were instrumented with piezometers to obtain more accurate
ground water data in the First Construction Zone.
RESULTS
Water pressure tests indicated, in general, that the dolomite strata
under consideration had very low permeabilities and that large water in-
flows into tunnels or into the storage chamber would apparently be
limited to fractured zones that may be present.
Excellent correlation was obtained between stratigraphic logging and
geophysical borehole logging as shown on Fig. 12.
Laboratory analyses were performed on selected rock samples to establish
the general range of properties of the various strata. The following
tests were performed: specific gravity, unconfined compressive strength,
modulus of elasticity (static and dynamic), drillability, natural water
content, absorption, abrasion, porosity, permeability, petrographic
analyses, x-ray analyses, chemical analyses, wetting and drying, and
solubility. A partial summary of field and laboratory data is presented
in Fig. 13.
The evaluation of the various rock strata based on physical examination,
geophysical borehole logs, and laboratory analyses indicated the fol-
lowing formations best fulfilled the geologic criteria: Waukesha
Joltet, Wise Lake, Dunleith, Guttenberg, Nachusa, Grand Detour, and
Mifflin.
152
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GROUND WATER DRILLING AND TESTING
PURPOSE
A detailed ground water testing program was performed [1) to determine
the hydraulic characteristics of the hydrogeologic units shown on Fig.
14, (2) to determine the feasibility of aquifer protection by artificial
recharge methods, and (3) to provide ground water observation wells.
Ten water wells with a total footage of 11,800 ft. were drilled during
the period from November, 1967 to March, 1968. The wells included one
deep aquifer test well, three observation wells, and six specific ca-
pacity wells.
FIELD METHODS
The water wells were drilled by the cable tool method and the air rotary
method. After completion of the drilling, each well was geophysically
logged to establish the stratigraphy so packers could accurately be set
and the selected hydrogeologic units isolated and tested. A total of
20 pumping tests and two recharge tests were conducted in the specific
capacity wells and in the deep aquifer test well.
Specific Capacity Wells. The Silurian aquifer system and the Galena-
Platteville hydrogeologic unit were tested in each of the six specific
capacity wells. Each well was drilled and cased through the overburden
and then drilled through the Silurian to the top of the Maquoketa. The
Silurian aquifer system was then pump-tested. After testing, the well
was drilled to the top of the Galena and cased through the Maquoketa.
Drilling was then continued to the top of the Glenwood. A packer or a
concrete plug was set at the Platteville-Gleriwood contact and the
Galena-Platteville unit was pump tested.
Deep Aquifer Pump Testing. Seven pumping tests were performed in the
deep aquifer test well. These tests were designed to evaluate the
Silurian aquifer system, the Cambrian-Ordovician aquifer system, the
Galena-Platteville hydrogeologic unit, the Glenwood-St. Peter hydro-
geologic unit, the Prairie du Chien-Eminence-Potosi hydrogeologic unit,
the Franconia hydrogeologic unit, and the Ironton-Galesville hydro-
geologic unit.
The deep aquifer test well and the observation wells were drilled and
cased through the overburden and then drilled through the Silurian to
the top of the Maquoketa. The Silurian aquifer system was tested and
the wells were then drilled to the top of the Galena and cased through
the Maquoketa. The wells were then drilled to the top of the Eau Claire
Formation at a depth of approximately 1685 ft. Each hydrogeologic unit
was isolated by inflatable packers and tested individually.
153
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Recharge Tests. After completion of the deep aquifer pumping test,
two recharge" tests were conducted in the deep aquifer well. Drinking
quality water was injected into the various hydrogeologic units and the
build-up of water levels was observed in the observation wells.
The Galena-PI atteville hydrogeologic unit was isolated from the under-
lying hydrogeologic units in the two observation wells by means of a
cement plug. An observation pipe was placed through the cement plug
in each observation well to permit measurement of the water level in the
underlying hydrogeologic units.
The hydrogeologic units to be recharged were isolated in the deep aquifer
test well fay means of inflatable packers.
In recharge test 1, water was injected through the Galena-Platteville,
Glenwood-St. Peter, Prairie du Chien, Eminence, and upper 80 ft. of the
Potosi as shown in Figure 15 A. Recharge test 1 was continued for a
period of about 10 days as shown in Figure 15 B. The rate of recharge
averaged 243 gpm and the build-up in the recharge well was 125 ft. at
the end of the test.
In recharge test 2, water was injected through the Galena-Platteville
and Glenwood-St. Peter hydrogeologic units as shown in Fig. 16 A. Re-
charge test 2 was continued for a period of about four days as shown
in Fig. 16 B. The rate of recharge was 60 gpm initially, but was de-
creased to 15 gpm because of overflowing of the recharge well. Even
at the lower recharge rate the well overflowed in four days and the
test was discontinued. The recharge rate for the four day period av-
eraged 16 gpm.
The water levels in the two observation wells had not completely re-
covered from test 1 when test 2 was started as shown in Fig. 16 B.
Complete recovery of the water levels from test 1 was not achieved
prior to the start of test 2 because of contractual time restrictions.
RESULTS
The results of the specific capacity tests are presented in Table 1
and the results of the deep aquifer pumping tests are presented in Table
2.
Analysis of the recharge test results indicated the following:
1. The hydraulic characteristics of the St. Peter sandstone
are too low to permit economical injection rates into this
unit to develop the necessary ground water mound.
2. Recharge wells will have to be drilled into the Potosi Forma-
tion to obtain the required hydraulic characteristics to
-------
develop the ground water mound necessary to protect the aquifer.
3. Recharge rates during the tests were lower than predicted on
the basis of pumping test results. This is believed to have
been caused by (a) chemical composition differences between
the recharge water and the natural ground water, (b) temperature
differences between the recharge water and the natural ground
water, and (c) aeration of the recharge water.
The aquifer protection system, shown in Fig. 17, consists of maintaining
a positive ground water head on all unlined structures to insure inward
seepage rather than leakage of contaminated waters. The water table in
the Silurian aquifer system is above all tunnels. Fig. 17 shows the
current (1968) position of the Cambrian-Ordovician water level, the
future water level without recharge, and the water level with recharge.
The ground water testing program demonstrated the feasibility of an
artificial recharge system to protect the ground water resourses in the
vicinity of the proposed project.
SUMMARY
To obtain the most favorable geological condition for deep tunnels to be
constructed by mechanical moles, the tunnels should be located in struc-
turally sound and uniform rock strata with a minimum of potential ground
water problems. If the tunnels are designed to be unlined and to carry
sanitary water, it is necessary to carefully evaluate the ground water
conditions to assure this valuable resource from becoming contaminated
by outward seepage from the tunnels.
155
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SELECTED REFERENCES
Birdwell Division, 1968, Borehole logging service for the Chicago!and
Deep Tunnel System for pollution and flood control.
Harza Engineering Company and Bauer Engineering, Inc., 1968, Chicago!and
Deep Tunnel System for pollution and flood control, first construction
zone, definite project report, appendix G and H.
Harza Engineering Company and Bauer Engineering, Inc., 1969, The impact
of the Deep Tunnel Plan on the water resources of northeast Illinois.
Seismograph Service Corporation, 1968, Report on a Vibroseis Survey for
the Metropolitan Sanitary District of Greater Chicago, Chicagoland
Deep Tunnel Plan for pollution and flood control;
Phase I—mobilization and reconnaissance
Phase II—-first construction zone
Phase Ill-total combined sewered areas
-------
CREDIT FOR THE CHICAGOLAND DEEP TUNNEL PROJECT
Client The Metropolitan Sanitary District of
Greater Chicago
Chicago, Illinois
Consulting Engineers . . Harza Engineering Company
Chicago, Illinois
Bauer Engineering Inc.
Chicago, Illinois
Geophysical Exploration. Seismograph Service Corporation
Tulsa, Oklahoma
Borehole Birdwell Division of Seismograph
Service Corporation
Tulsa, Oklahoma
Core Drilling DiKor - Groves
Carmi, Illinois
Ground Water Drilling . Layne-Western Company
and Testing Aurora, Illinois
157
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Advanced treatment
Sewage treatment
Reservoir
Treated water
Combined sewer
MSD intercept or
Possible underflow
I Tunnel
L—
Mined Storage
Conveyance tunnels
Flow
Reversible pumped-storage
.Hydroelectric plant.
THE DEEP TUNNEL CONCEPT
Fig. 1
158
-------
GENERAL MAP
Fig. 2
159
-------
88°00'00"
4?°07'30" -II HIM Illl
•)2°oooo -i 1111111111111111111111 M 1111 n 1111111111111111 M
COOK COUNTY
"WILL ""COUNTY
.,- v/ jr&
4 l°4 5 00 -I 1111 I 111 I I 11 I 111 11 I 11 I I I I I I If I Ml 111 11 I 11 111 I I I I I I 11 I r
«i°30'oo" -i ..... i ....... nun ii ..... i ....... inn ........... ii ii mi mi i in in mi M in IIIIIIIMII 1111 ii ii 1 1 M
'"
3000
88«00'00"
INDEX MAP
•ig. 3
LoO
-------
4^
A
*
.Surface
REFRACTION PROFILE
.Top Niagaran
Limestone
Fig. 4
vvvrv
•Surface
Top Niagaran
Top Maquoketa
Top Galena
.Top St. Peter
REFLECTION PROFILE
Fig. 5
-------
Fig. 6
-------
SEISMIC DATA PROCESSING
FLOW DIAGRAM
DATA AQUISITION
o
Ul
i =
8: °
Ul
en
o
UJ
» z
J <
u1 Q
HI
a;
4 1
MAGNETIC
FIELD TAPE
r
ANALOG
TO
DIGITAL
CONVERTER
IBM
360/40
DIGITAL
DATA PROCESSOR
IBM
360/40
DIGITAL
DATA PROCESSOR
DIGITAL
• TO
ANALOG
CONVERTER
FINAL PRESENTATION
Fig, 7
-------
GENERALIZED STRATIGRAPHIC COLUMN OF THE
CHICAGOLAND AREA
^r^f
i i
i i
i
i i
.i'j ,
.-.-#-
jf-_c*
•y^r
f
/ /
7 /
&^~~*1
"" /
/ /
( /
If
Sfe
i r"\
i /
/ / -
/ /
—-—
~^^~-
f?#?
m
s* ^~
'Ts'
^
Thickness
50'- 150'
150 '-300'
20'- 140'
100'-250'
170'-225'
100'- 150'
0-80'
100'-600'
0-340'
50'-150'
' 90'-220'
50'-200'
80'-130'
10'-100'
370'-575'
1200'-2900'
System
Quaternary
Silurian
Ordovician
Cambrian
Precambrian
Series, Group, or Formation
Glacial and lake deposits
Niagaran Series
Alexandrian Series
Maquoketa Group
Galena Group
Platteville Group
Glenwood Formation
St. Peter Formation
Prairie du Chien Group
Eminence Formation
Potosi Formation
Franconia Formation
Ironton Formation
Galesville Formation
Eau Claire Formation
Mt. Simon Formation
Lithology
Sand and clay
Dolomitic limestone
Dolomitic limestone
Shale and dolomite
Dolomite
Dolomite
Sandstone, shale & dolo.
Sandstone
Dolomite and Sandstone
Dolomite
Dolomite
Sandstone, dolo. and shale
Sandstone
Sandstone
Shale, dolo. & sandstone
Sandstone
Granite
Seismic Velocity
2000-8000 ft/sec
16,500- 19,000 ft/sec
16,500-19,000 ft/sec
13,000- 15,000 ft/sec
18,000- 19,500 ft/sec
18,000-19,500 ft/sec
13,000-1 8,000 ft/sec
15,000-1 7,000 ft/sec
17,000- 18,000 ft/sec
17,000- 18,000 ft/sec
17,000- 18,000 ft/sec
17,000- 18,000 ft/sec
17, 000- 18,000 ft/sec
13,000- 16,000 ft/sec
Seismic mapping level
lt>-
Stratigraphic Column Modified From:
T. C. Buschbach
and
H. B. Willman, Illinois State Geological Survey
Fig. 8
-------
GEOLOGIC STRUCTURE-TOP OF GALENA
49 HOLES + SEISMIC
Fig. 9
165
-------
•••;••;(-• •;"'
lilt il.UI"
o
T g !' '
< 2
.... ^ jj
> m
: s i::;:::. '
0
Z"' '-
. ^ >
"' • r^«i*n»«i*»*
^» »1'""!
t
CO
m
>
30
5
. > ,
' <
i .
v, . .,
DEPTH
I—
-------
Fig. 11
16?
-------
DEPTH
lo-
3-D VELOCITY
MiCBOSKONDS
100O 400
GAMMA RAY-
NEUTRON DENSITY
CALIPER
INCHES
HOCK PROPERTIES
600 —
700 —
eoo
1000 —
s r SK roof roi
.
s SMEAB *Avi TIME
P PBEiSURf *AV€ TIMf
ROCK PROPERTIES
S SHEAS MODIMU5 ' 1*0* *-G*OSiTY
0 BUIK IV.ODU1US DC DEMSIIV
E TOONG S MODUtUS Kit POiSSON S »ATIC
ElEVATiON: 586.!
D€PTH tOGGED: 1044'
FLUID tmi: 120'
CASING SET AT: 190'
BOREHOLE GEOPHYSICAL DATA
Fig. 12
168
-------
GROUP
SERIES OR
FORMAT I ON
GRAPHIC
COLUMN
PREDOMINANT
ROCK TYPE
AQUIFER
Till lenses
GLAC t At
our FT
Pleistocene
of sand and
Niagaran
and
Alexandrian
rrro
Oolomitic
1imestone
S!LURI AN
Maquoketa
Galena-
Platteville
Dolomite
G)enwood-
St.Peter
Sandstone
Prairie Du
Chi en,
Eminence
and
Potosi
Dolomite
Sandstone
Franconia
Ironton-
Galesvi1le
Sandstone
Eau Claire
Sandstone
Mt. Simon
MT.SIH8*
AQUIFER SYSTEMS
Fig.
169
-------
OW-2
OW-I TW-I
Avg. 2U3 gpm
10 days
RECHARGE TEST NO.1
Fig. 15
170
-------
Ow-2
PLE I STOCEIIE
SILURIAN
GALENA-PLATTEVILLE
GLENWOOD-ST. PETER
PRAIRIE OU CHIEN
EM I HEXC£
POTOSI
OW-I TW-
U . •
16
t 2! 2 °° * ~
'M ' •«•* «HI»J»««) "!
-------
-Recharge well
Water table, Silurian
aquifer
0 -
-300
-600-
o,
8
i
-900
GLACIAL*- DRIFT
- PL ATTEVTlLE
PETER
» Ji" « o o a
.51^^s=5^V-^00-^<*^i^kfRAIR}E DU CHEN,^ EMINENCE^*
-i aoo^^ff-*; PS^L^I° • f^L^i r/» S^» -^Tt^:." -p *"- • - *•> r^-- ^-" °«
-^-r- P~Z ~r—7— O^7 "~l tf*-^S*^aJ£f?^ - «—•'' JL^. - "^4^
-1500-
-18004 '-
IRONTON-6ALESVILLE
- EAU CLAIREJ,
AQUIFER PROTECTION
Fig. 17
172
-------
PUMPING TEST INFORMATION - DEEP AQUIFER TEST SIT!
Depth !/;. I
Hydrogeo!vg:c
Unit Tested
Silurian Aquifer
Cambrian -Ordovician
Aquifer
Ga 1 e n a - P 1 a 1 1 e. v i 1 1 e
Glenwood-S:. Peter
Prairie Du Cnicn.
Eminence & Pctosi
Fran con i a
Ir o nt o r, - G a ! e s v i 1 1 e
Top of
Bottom
Packer
•495-0'
168-4 -O1
900.0
1016.9
l?66.7
147S.6
1684. 01
Bottom
of Top
Packer
60. 03
614. 02
614.0s
919.6
1116.1
1373.^
1499.6
Diame •
:er
(in.)
16
12
8
8
i 2
12
12
Pene-
tration
Ifl.J
435.0
1070.0
236.0
97.3
250.6
99.9
184.4
Date
Tested
12/11/67
2/14-16/68
2/23/68
2/19-21/68
2/25-29/68
2/3-5/68
1/28-30/68
Length
of Test
(mm. )
158
1844
31
1773
1825
1S41
1808
Nan-
pumping
Level
(ft. t
24
434
439
435
434
434
434
Pump-
ing
Rate
(gpm)
40
380
40
41
350
300
300
Draw-
doun
ill.)
407.0
26.4
401.0
310.1
26.9
237.0
100.0
Specinc
Capacity
fgpm, /t. >
0.098
14.400
0.100
0.132
13.020
1.266
3.000
3'->ttom of well.
Rouon. ol casing.
NOTE: 1 '.-1 was the pumped well in all but the Gler.wood-St. Peter and Galena-Platteville tests. OW-i was the pumped v.eil
for these :v, o tests.
Table ^1
PUMPING TEST INFORMATION - SPECIFIC CAPACITY TELLS
Depth
Veil \o if;.)
Diameter
:!i.}
Penetration
'it. }
Length Son pump ing
of Test Level
Date Teslei (mm.) ift.)
P urn 3 in g
Rate
Drawdown.
'ft- )
-pecific
Capacity
(gpm. ?!. )
Silurian Tests
Sff-1 453
SW-2 550
S'i-3 426
S'*'-4 549
S«'-5 -489
SK'-6 ?--3
Stt'-l 87 4
SU -2 vSCl
S'X'-3 H3
S'A-4 ?70
S\V-5 PSO
SW-6 °"0
12
12
12
12
12
12
8
S
S
8
S
S
393
475
381
457
431
•560
316
294
319
291
325
312
I2j 6-7/67
12/13/67
1/8/68
1/29-30/68
1/31-2/1/68
1/22-23 ''68
2/15-16 68
Galena-Platteville
1 2/6-7 -'6S
1/8-9/68
1. '19-20 68
3/5/68
1/30-^3 -'63
2/28,68
49
224
677
629'
699*
720
721
Tests
720
719
"21
56
720
-45
35
46
16
42
28
46
453
357
433
395
503
431
10
30
56
60
60
30
40
30
50
30
60
40
121
332
385
347
64
357
145
292
267
411
53
398
0.083
0.090
0.145
0.173
0.938
0.084
0.276
0.103
0.187
0.073
1.132
0.101
Length o: test ce.'ore aciciizi!
2 Length c; test aftor acidizing
Table *
173
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Section 10
THE CONTRACTORS VIEWPOINT OF THE HARD ROCK MECHANICAL MOLE
WHAT'S CAUSING DOWNTIME? WHAT DO THEY WANT?
by
Victor L. Stevens
Mining Consultant
821 Kearns Building
Salt Lake City, Utah 84101
-------
CONTRACTOR'S VIEWPOINT OF THE HARD ROCK MECHANICAL MOLE
WHAT'S CAUSING DOWN TIME?
WHAT DO THEY WANT?
I believe the tunnel contractor's greatest dream is to bid a tunnel with
a mechanical mole, estimating the exact cost and time and when he holes
through. The permanent lining, if it requires lining, is within one day
of completion.
Digressing from the specifics of the subject title, I would like to ap-
proach the problems from the overall concepts of Mechanical Moleing.
The subject of Mechanical Moleing goes far beyond the machine itself.
Let us view the subject on the broad concept and break it down into the
respective components and analyze each part. Mechanical Moleing can be
broken down into four basic categories, namely: (1) determination of
ground conditions ahead of moleing; (2) the Mechanical Mole itself; (3)
muck removal from the tunnel and transportation of men and supplies;
(4) ground support methods (both temporary and permanent).
Up to the present time, I believe that determination of ground conditions
ahead of moleing is the one feature that the tunnel contractor needs the
most help in to save valuable down time and extremely high costs. In
so many cases if the contractor knew the conditions ahead of moleing, he
could take care of the problem prior to the element of surprise. These
conditions could be fault zones, running ground, water, gas, squeezing
or heaving ground, just to name a few of the surprises mother nature
has in store for the underground excavator.
I would like to show a few examples of ground conditions that were not
anticipated in a moled tunnel by prior exploration. The first figures
are of the Oso Tunnel, a part of the San Juan Chama Project in south-
east Colorado.
Fig. 1 shows a tunnel profile with the bad ground conditions shown in
a circle. There were nine holes drilled (down to tunnel grade) along
the tunnel center line prior to bidding. A contractor who bid on the
job drilled an additional hole in the valley at Sta. 660+50 to check
for a possible fault. There was not a fault and the formation conform-
ed in dip and strike of the shale bedding with all the other holes.
The mole was started at the down stream portal and moled into about Sta.
721+50 when water, sand, gravel was encountered and caused the back of
the tunnel to cave in on the head of the mole without any warning. The
tunnel was then enlarged conventionally to allow for steel spiling to
be driven over the mole. The mole was then taken out of the tunnel to
give room for driving conventionally through the bad ground. As soon
as the mole was out of the tunnel, three diamond drill holes were
drilled in the face of the tunnel to try to determine the ground con-
177
-------
ditions. The holes were drilled 150 ft. long, +15°, - 15°, and level
and it was found that silt, sand, gravel, boulders and water were
directly ahead and the conditions bad enough so it was almost impos-
sible to drill any further than the 150 ft. At this point seven holes
were drilled from the surface and it was determined that there was 1000
ft. of glacial till to drive through before reaching the shale as orig-
inally expected.
(Fig. 2) In this case there was a hole at the down stream portal and
one 3000 ft. from the portal showing the same dip and strike of the
shale bedding and yet there was 1000 ft. of extremely bad ground in
between which could not be determined by the drill holes or surface
examination. If a good seismograph program had been performed prior to
bidding, this condition would have been determined and remedial action
could have been taken. The ground could have been grouted or drained
of water and while this was going on the contractor could have been
driving the tunnel from the other portal. The 1000 ft. of bad ground
tunnel could have been driven for $300 to $400/foot of tunnel instead
of the $1000/foot.
Fig. 3 shows the extent of the steel spiling to support the ground prior
to removing the mole. Fig. 4 shows the 6 in. channel spiling as driven
so as to support the tunnel. Fig. 5 shows the face of the tunnel being
breast-boarded to keep the face from running prior to and during spiling.
The second case of surprised ground conditions was at the water-hollow
tunnel job, a part of the Central Utah Project at Strawberry, Utah.
There were very few holes drilled on this project and only short holes
close to the both portals as shown in Fig. 6. There were surface out-
crops of the general formations and from a stratographic standpoint you
could get a good idea of what ground conditions you might expect.
There were two potential fault zones that showed up from surface exam-
inations. In the driving of the tunnel, proper precautions were taken
by putting in steel sets and installing water pumping lines to take
care of the water. The tunnel was driven through these areas with little
or no trouble.
At a point about 3 mi. in from the downstream portal, the tunnel went from
good ground into an extremely bad fault zone carrying gravel, fault-
gauge and water up to 1200 gal./min. at very high pressures. The
length of this fault zone was 350 ft. long and changed rapidly from one
type of disturbed ground into another, gouge to conglomerate, to gravel
to gouge to siltstone, etc. It was necessary to spile more than one-
half the distance solid with 48* rail, back packed with hay and timber
to prevent the ground from running and also for support of the heavy
tunnel arch. The steel channel spiling was driven by means of pneumatic
spaders. The large 48# rail was driven with the gripper pads of the
mole itself, this system was very fast and efficient.
-------
Fig. 7 shows the channel spiling on the tunnel ribs with wooden block-
ing to prevent the ground from running. Fig. 8 shows the 48# rail in
the back, of the tunnel vath the hay between rails. Fig. 9 shows the
mole thrust cylinder covered with sand, gravel, gouge prior to clean-
ing up with vacuum car. An extension pipe of 150 ft. long was put on
the vacuum car and suclced the loose material from around the mole and
up to the tunnel face. Fig. 10 shows the vacuum car.
The third case of unexpected ground conditions at the Azotea tunnel
which is a thirteen-mile tunnel part of the San Juan Chama Project in
northern New Mexico. The problem in this tunnel was in a 8000 ft.
stretch in the center of the tunnel. The problem was not a major fault
itself, but the side effects of a major fault. There were a series of
displacement or drag effects that appeared tight and undisturbed at the
time of mole penetration but started to take weight and movement oc-
cured many months later. If this condition had been known prior to mole-
ing, then the tunnel could have been bored large enough to put in support
steel. A geophysicist in the area had made determinations from oil well
drill logs close to the tunnel area prior to the driving of the tunnel
that showed these conditions would exist but he could not be heard by
the proper people and gave up. His maps made prior to tunnel driving
showed almost exactly the problem area.
I believe all the stated examples could have been determined ahead of
time with adequate geological and geophysical examination and determin-
ation. If the conditions were determined ahead of moleing the contract-
or would have been better prepared to cope with the problems, saving
considerable time and money. He could have had the proper tools and sup-
plies on the job for grouting, ground support, water handling, or any
other proper construction procedures, etc. I believe the oil field
geophysicists with their exotic means of ground determination in con-
junction with our tunnel geologists can aid and assist the excavator
in the area of ground determination ahead of moleing. At the present
time I am informed there are studies going on in California with "sonic"
methods being used in an active tunnel, to determine ground conditions
ahead of excavation and a report is to be published early in the coming
year by the University of California.
I would like to now pass to the third phase of our tunnel breakdown,
namely muck removal and transportation. Muck removal in tunnel moleing
shows the greatest overall delay time. In the case of the Oso tunnel
where the contractor made as high as 412 ft. in 24 hr., the mole avail-
ability was only 68% due to muck removal delays in train switching, etc.
Mucfc removal means, such as slurry, hydraulic or pneumatic systems,show
the greatest promise for continuous, fast, efficient muck transportation
from the tunnel excavation. In conjunction with such systems, means
must be developed for the transportation of men and supplies
into and out of the tunnel heading. The method of transportation for
men and supplies would be directly related to the muck removal system,
but could be by rail, off-track equipment or mono-rail.
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The fourth phase In tunnel moleing, namely, ground support temporary
and permanent, is directly related to the other three phases of tunnel
moleing. Ground conditions tell us what type of supports will be needed
and how and when. The moleing rate tells us how and when, and the muck
removal system tells us how and when. For example, if the ground is
weak and not self-supporting, then support must be put in around the
mole at the immediate tunnel heading. If the ground is self-supporting
then support, if required, can be put in back of the congestion of the
moleing operation. If a muck removal system is used other than by rail
transportation, then the permanent lining can be put in with ease in
conjunction with the moleing progress. The installation of permanent
lining of the tunnel in conjunction with the moleing operations approach-
es the ultimate in tunnel driving, where permanent lining is required.
The system was tried at the Azotea tunnel in conjunction with the slurry
system of muck removal. It was used successfully for 1000 ft. of tunnel
but had to be abandoned because of continual failures of the slurry sys-
tem. The tunnel was then driven with a Robbins Mole, muck cars and
temporary support until the tunnel was holed through and the permanent
lining was installed. (The present methods most generally used for
ground support at the tunnel face are circular steel ribs with metal or
wooden lagging and roof bolts with plates, steel lagging or wire mesh.)
I believe a continuous method of applying gunite or shotcrete at the
molehead should be developed. This could be done on a rotating arm
the proper distance from the tunnel rib and advance controlled with the
advance of the mole.
There is also a patent pending for a continuous rolled steel lining
similar to the method of rolling ventilation pipe, this could be put
in at the molehead on a continuous basis.
Now let's consider the second phase.of Mechanical Moleing, the mole it-
self. Contrary to some people's thinking, I believe of the four phases
of Mechanical Moleing, the moleing phase is presently far ahead of the
other three. However, there are many improvements to be made in present
day moles, and I would like to present what I think should be developed.
There should be two sets of gripper pads, one set in the front and one
set in the rear. This would allow a choice of positions for gripping
in case the ground was bad in front and needed support or could not
properly grip in bad ground. This would also assist in case the mole
was required to go on a plus or minus grade. A vertical raising or lower-
ing on the gripper pad support could be developed to readily give align-
ment for grade control, this would remove a control pad from the invert
of the tunnel to allow greater working room. Two sets of gripper pads
would eliminate intermittent moleing progress because of regripping time.
Differential and controlled gripping pressures on either side of the
tunnel gripper pads could be advantageous in variable ground conditions
and also could aid in guidance control. Differential gripping pressures
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could be advantageous in enlarging the tunnel section to allow for
passing tracks, switches, or transformer stations, etc., etc.
The main support beam of the mole should be as small as possible and
high off the invert as is possible to give greater working room on the
tunnel invert.
Moles should be made to be able to be knocked down into small component
parts so as to be able to be moved into and out of working faces with
ease and speed. The access to the molehead should be such that it is
possible to make rapid changes of cutter bits.
Lubrication systems should be made automatic or semiautomatic so ser-
vicing can go without mole stoppage. Automatic controls should be put
on moles, not necessarily to eliminate manpower, but to make for a smooth-
er operation for alignment control and steady penetration rates.
Rapid changes in line and grade are hard on cutter bits, the molehead,
the thrust bearing and the main frame itself.
It would be very advantageous to have the molehead so it could be easily
expanded from the operator's control cab for tunnel enlargement, this
was used in some moles with fair success but needs further development.
Moles should have a longitudinal center opening so that test drilling
can go on for ground determination independent of the progress of the
moleing operation.
It would be advantageous for moles to have a variable speed head rotation
for maximum efficiency for ground penetration in variable ground condi-
tions. (This lesson can be learned from our oil drilling friends.)
Moles should be equipped with segmented shields for ground support until
temporary support can be put in. Each segment of the shield should be
independently operated, both in and out on radius and back and forth
along the tunnel line. This would allow the installation of support in
extremely bad ground.
Moles should be equipped with vacuum machines to clean the tunnel invert
to allow the pouring of sub-invert or final invert directly behind the
mole.
In conclusion I would like to state the following. I believe there
should be a standardization in tunnel sizes within certain limitations.
It seems to me we are defeating the purpose of rapid excavation to have
to spend such large sums of money for a system to have it outmoded by a
size change. I would suggest, for example, that with very few excep-
tions all tunnels could be standardized into three sizes: 12 ft., 18 ft.
and 28 ft., each one of which would have a plus or minus one-foot
variance. This would allow a contractor a better opportunity to develop
and amortize a rapid excavation system over many more feet of tunnel to
the overall financial benefit to the owner.
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I believe with some of the aspects I have mentioned, downtime can be
cut to a minimum and that these are some of the things a tunnel con-
tractor wants and needs.
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-
•
OSO TUNNEL
CHROWO COLORADO
FROM JULY 1966 TOSEP67
Fig. 1
Water Saturated,
Unconsolidated Sand,
Gravel and Boulders.
•- V: • :• ;__£ -
HORIZ SCALE I"' 1.000'
-STATIOHS-
BAD GROUND DETAIL
183
rbYllS • I OS. DRILLIN0 CO. *^™ (z]
OSO~TUNNEL. ^ Ts SHOWN
CHROMO COLORADO n
FROM JULY I9S6 TO^EP67 «_14_TO _
Fig. 2
-------
Fig. 3
Fig. 4
Fig. 5
18U
-------
5 T A T I O N S
TUNNEL PROFILE
WATER HOLLOW TUNNEL
(STRAWBERRY AQUEDUCT)
FROM NOV 1968 TO MAR. 1970
_ONE i n
AS SHOWN
"4 15 70
Fig. 6
Fig. 7
Fig. 3
185
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Fig. 9
Fig. 10
186
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Section 11
RAPID EXCAVATION IN HARD ROCK:
A STATE-OF-THE-ART REPORT
by
William E, Bruce
Supervisory Mining Engineer
&
Roger J. Morrell
Mining Engineer
Twin Cities Mining Research Center
Bureau of Mines
U.S. Department of the Interior
Minneapolis, Minnesota
187
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RAPID EXCAVATION IN HARD ROCK--
A STATE-OF-THE-ART REPORT
ABSTRACT
In the United States, 12 tunnels have been machine bored since 1955 in
rocks of over 20,000 psi compressive strength. One-half of these opera-
tions were performed in a manner superior, in both the speed of boring
and the quality of the opening, to conventional drill and blast methods.
The other one-half were either partially successful or failures, and
the machine had to be replaced by conventional methods. Boring machines
have been making steady improvement in their ability to bore hard rock,
and some recent tunnels have been successfully bored in rocks of up to
30,000 psi compressive strength with maximum advance rates of up to
1,500 ft./mo.
This paper describes the evolution of present day tunnel boring tech-
niques. Emphasis is directed toward selected cases from the past
decade which are discussed in some detail. The data presented has, in
many cases, been generated by Bureau of Mines personnel during on-site
studies of the particular job. Wherever feasible, samples of the rocks
being bored were returned to the Twin Cities Mining Research Center for
determination of the physical properties.
This paper presents the significant problems and accomplishments for
various actual operations. Wherever possible, it presents physical
characteristics of the rock encountered to aid the audience in evalu-
ating rock hardness.
Trends for the future are forecast relying on objectives as developed
by the OECD* as well as on experience of Bureau of Mines personnel who
for years have followed developments in rapid excavation^ technology.
INTRODUCTION
Tunneling by machine is generally classified as hard rock or soft ground
tunneling. Each classification has unique problems and requires dif-
ferent techniques and equipment. This paper describes the state of the
art of rapid excavation in hard rock.
Organization for Economic Cooperation and Development Advisory Confer-
ence on Tunneling; Washington, D.C., June 22-26, 1970,
2 The term "rapid excavation" is defined in this paper as excavation per-
formed by tunnel boring machines or moles and does not include conven-
tional drill and blast methods.
189
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To begin the discussion of machine tunneling in hard rock we must first
define the term "hard rock." This definition must necessarily be
arbitrary since the ability to fragment rock is a function of both time
and the fragmentation process. For example, what is considered hard
rock for today's machines may be considered soft rock in the future; and
rock which is impossible to break by conventional moles may be readily
broken by hydraulic processes.
Considering only present-day machines, however, we would define hard
rocks as sediments or metasediments (metamorphosed sedimentary rocks)
with a uniaxial compressive strength greater than 20,000 psi. This
would include the common varieties of dolomite, limestone, sandstone,
shale, marble, slate, etc. In the definition of hard rock, we would
include other metamorphics and igneous rocks with uniaxial compressive
strength greater than 10,000 psi^. This classification would include
rocks such as schist, granite and basalt. In addition, we would in-
clude other difficult to mole rocks such as those that are blocky by
nature, badly fractured in situ, or conglomeritic in nature. Soft rock
is alternatively defined as sediments or metasediments with uniaxial
compressive strengths less than 20,000 psi and as other metamorphics
and igneous rocks of less than 10,000 psi compressive strength.
DEEP-TUNNEL PROJECTS
Deep-tunnel projects, such as those being developed in the Metropol-
itan Sanitary District of Greater Chicago (MSDGC), offer many benefits
to our environment. The combined storm and sewer system includes an
interceptor network to alleviate flooding of specific urban areas. The
combined system offers economies because it eliminates construction of
two separate systems. A combined system may cost only one-third as
much as a separated system, and the incorporation of hydroelectric pump-
ed storage may contribute income which can reduce the net cost of the
entire system.
Additional benefits are realized by a combined storm water and raw-
sewage system. The combined sewer system is designed to deliver effluent
of a quality which will meet new stringent standards. The storage capa-
Note that while the definition of rock hardness was based entirely on
rock compressive strength, it is well recognized that this parameter is
not a complete indicator of boreability. There are many researchers,
including those at the Twin Cities Mining Research Center, who are try-
ing to develop an accurate, universally accepted boreability index.
Until one is developed, however, rock compressive strength will remain
as the one common parameter recognized by the entire tunneling community
as being related to boreability.
190
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city is a safety valve to elminate problems of sewage overflow during
periods of high rainfall.
The smoothing out of the power supply-demand curve by the use of pumped
storage offers advantages. Because power can be generated to meet
high demands using release of surface water to underground storage,
customer needs may thus be met without the atmospheric pollution associ-
ated with some coal burning plants.
Finally, if water table recharge by injection wells is incorporated,
ground water levels, which historically have been falling, could be
maintained at desirable levels. All these advantages are in line with
the desperate need of a society intent on improving its environment.
Public officials equating the advantages of environmental and safety
improvements with fiscal and budgetary constraints are necessarily sen-
sitive to cost factors including excavation costs.
Rapid excavation in hard rock holds promise for diminishing project
costs; however, such excavation is sensitive to the laws of supply and
demand. We are all aware of the pace of excavation needed to provide
efficient services demanded by the public. Advances in fragmenting
hard rock are needed now to provide high-speed underground transportation,
efficient underground emplacement of utilities, and economical develop-
ment and production of the Nation's mineral reserves. Our future
needs will be even more demanding.
TUNNEL BORING - PAST AND PRESENT
Although tunnel boring machines have evolved over the last century,
the 1950's saw the first extensive use of mechanical moles.
The early successes were achieved with Robbins boring machines in
the tunnels of the Missouri River Basin in the 1950's. The rocks
encountered, although bored successfully, might well be considered
to be very soft sedimentary rocks, probably in the 5,000-to 10,000-
psi range.
The dawn of present-day tunnel boring probably occured in the 1960's.
During the sixties, noteworthy advances were made, but not without
equally spectacular failures.
Before beginning a discussion of tunnel boring in hard rocks, we will
summarize the results achieved during the sixties in what we have
defined as soft rocks. Although this brief discussion will make no
mention of earth-boring ventures, it should be remembered that many
earth-boring jobs have been undertaken during the past two decades.
In 1961, a Robbins machine operated with limited success in the Kerr-
McGee Corp. Section 33 mine near Grants, New Mexico, in sandstone
191
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ranging from 1,200-to 2,500-pst, Here progress was limited both by
adverse water conditions and by rock too soft to withstand forces re-
quired to anchor the mole. In 1961, a Robbins machine bored 8,000-to
15,000-psi material in the Homer-Wauseca mine in Upper Michigan with
limited success, primarily because of directional control problems and
adverse water conditions. Another project in 1963 involved two Hughes
machines and one Robbins machine boring an Arizona water-diversion
tunnel for the Phelps Dodge Corp. Success on this particular job was
also limited by water problems as well as guidance problems. The ma-
terial involved was sandstone ranging from 2,000-to 15,000-psi. Guidance
problems on many tunnel boring jobs led to introduction of the laser for
improved directional control of boring machines in the mid-sixties. In
1965, in the Navajo No. 1 tunnel in New Mexico, the Hughes Betti I ma-
chine, using a sophisticated laser guidance system, successfully bored
a tunnel in 5,000-to 10,000-psl sandstone and deviated less than 5/8 in.
along the entire tunnel. Starting in 1965, Jarva machines operating in
St. Louis successfully bored sewer tunnel in limestone ranging in com-
pressive strength from about 15,000-to 20,000-psi. At approximately the
same time, 1965 through 1967, Robbins moles successfully bored tunnels
in shales with strengths up to 10,000 psi at the San Juan-Chama project
in northern New Mexico and southern Colorado. The San Juan-Chama pro-
ject, consisting of three tunnels, set a record by boring about 420 ft.
during one 24-hr, period. This spectacular achievement was made in
the Oso tunnel which was also the site of a rather classical case of
changed conditions. Prospect holes spaced at about 1,000-ft. intervals
failed to delineate a zone of about 900 ft. of loosely cemented con-
glomerate which forced a temporary cessation of machine tunneling.
In 1967, a Calweld boring machine successfully bored a storm sewer in
the St. Peter sandstone underlying Minneapolis. The sandstone has a
uniaxial compressive strength less than 500 psi. Although the machine
performed successfully, an inrush of water occured shortly after boring
was completed, with the result that the machine was buried in debris for
several months.
So far, we have mentioned but a few tunnel boring operations carried
out during the past decade. We have reserved discussion of those opera-
tions which took place in what we have defined as "hard rock." These
cases are reserved for the main topic of discussion of this paper.
THE STATE OF THE ART OF HARD ROCK BORING
A typical U.S. manufactured hard rock mole can be described as a self-
advancing rotary drilling machine which cuts the full face of the tun-
nel in a semicontinuous fashion. Most machines consist of an inner and
an outer frame. The inner frame of the mole usually carries the cutter-
head which both rotates and advances forward as drilling proceeds. The
outer frame is kept stationary during the cutting process by means of
large hydraulic jacks which are forced out against the tunnel walls.
192
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From this stable position, the thrust and torque of the cutterhead are
reacted. The cutterhead {s fitted with a number of individual cutters
which cut or spall the rock as the cutterhead is rotated and forced
against the tunnel face. The cuttings are collected by buckets behind
the cutterhead and are discharged onto a conveyor which carries them
to the muck haulage system behind the machine. To illustrate some of
these features a Jarva Mole is shown in Figure 1.
BASIC CYCLE
The basic operating cycle (Figure 2) of a typical boring machine is as
follows: 1) To begin the stroke, the mole is aligned in the desired
direction of advance by the rib jacks which shift the axis of the mole
in the desired direction. These rib jacks also serve to lock the machine
securely in the tunnel when boring. 2) Boring proceeds as the thrust
cylinders force the rotating cutterhead into the tunnel face. The
torque and thrust of the cutterhead are resisted through the mole by
the rib jacks. 3) At the end of the forward stroke of the thrust cylin-
der, the rib jacks are released, the support jacks are lowered, and the
machine is moved ahead by retracting the thrust cylinder. 4) The mole
is again aligned in the tunnel and is ready to bore another stroke.
BASIC OPERATIONS IN HARD ROCK TUNNEL BORING
Rock Disintegration
The rock disintegration system of a tunnel boring machine is composed
of the cutterhead and the individual cutters mounted upon it. All hard
rock machines manufactured in the U.S. use some type of rolling cutters
which are usually hard-faced at selected spots with tungsten carbide or
which have sintered tungsten carbide inserts on the cutting surfaces.
The most popular cutters are either single or multiple disks with
tungsten carbide inserts on the periphery, or roller-shaped button bits
which have tungsten carbide inserts mounted around the entire surface
(Figure 3). The button bit is used in the hardest rocks where the rock
will not break out readily between two adjacent kerfs. The single or
multiple disks are used in hard rock where chipping between adjacent
disks is possible and thus give a larger chip product and usually fas-
ter penetration. Most cutters have replaceable cutter shells and bear-
ings so that, depending on which fails first, either the bearings or
cutter surfaces can be replaced separately.
Depending on the type of machine, the center section of the main cutter-
head can revolve either with the main cutterhead or independently. If
the center of the cutterhead revolves independently, it is usually
equipped with a tricone type cutter and rotated at a speed of 30 to 60
rpm. Usual practice is to use a thrust of 50,000 Ib./ft. of cutter-
head diameter and to use a rotary speed equal to 90 divided by the di-
193
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ameter In feet. The larger the cutterhead diameter, therefore, the
slower it is revolved; the speed of the outside cutters is thus held
at an acceptable level. The majority of the hard rock moles described
in this report had a rotary speed of 8 to 9 rpm, a maximum thrust
capability of between 1 and 1-1/2 million lb., and a maximum torque
capability of between 300,000 and 500,000 ft. lb.
Materials Handling
After the rock is broken from the tunnel face, it falls to the invert
of the tunnel where it is removed by buckets mounted behind the cutter-
head. As the cutterhead rotates, these buckets scoop up the broken
material from the invert and deposit it on the machine conveyor. This
is a belt conveyor, usually 24 in. wide, which carries the muck to the
end of the machine and, in the majority of cases studied, onto a trail-
ing conveyor. The trailing conveyor, which advances along with the mole,
is 20 to 30 in. wide and 200 to 300 ft. long and carries the muck from
the mole to the muck cars. Except for the White Pine machine, which
used conveyor haulage, all the machines studied in this report used
train haulage. The locomotive type and size varied as did the muck cars.
Most operations used a California switch to pass the empty and loaded
trains in the tunnel. The muck trains on the return trip generally
carry supplies, such as cutters or support materials, back into the tun-
nel .
Primary Support
In hard rock boring, where the rock is not excessively fractured, pri-
mary tunnel support requirements are usually minimal. The very nature
of machine boring is such as to create a minimum disturbance to rock
outside the tunnel walls. The result is a stable opening which re-
quires fewer and lighter supports. Of the tunnels studied in this re-
port, over one-half required little or no support. Except for one tun-
nel in blocky ground, the rest required only minor roof bolting or
shotcreting to control the tunnel roof. In two of the MSDGC sewer tun-
nels in Chicago (Jobs 8 and 9) the bored tunnel surfaces were of such
high quality that the final concrete lining was eliminated. Blocky
ground and occasional rock falls or water inflows from fault zones,
solution cavities, etc., still present problems in hard rock tunnels.
Therefore, many hard rock machines have both partial shields around the
top of the machine to protect them from these hazards and roof pinning
drills for the installation of roof bolts and mats for temporary sup-
port. All machines can be equipped with mechanical aids for setting
ring beam supports if greater support is necessary.
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Survey and Control
The maintenance of line and grade has become routine in recent years
with the use of the low power, continuous output laser which can project
a^thin beam of visible light for long distances. In a typical installa-
tion the laser is set up on the tunnel rib some hundreds of feet behind
the tunneler by conventional surveying methods. A reference beam on the
correct line and grade is then projected toward the mole where it strikes
two targets mounted at the front and rear of the machine. To keep the
mole on course, the machine is shifted to keep the beam centered on
these targets. In recent years many of these targets have been built
with photoelectric cells which are activated when hit by the laser beam.
These photoelectric cells provide a continuous readout of the mole's
attitude in the tunnel and can also be used to signal a servocontrol
system to automatically adjust the mole to keep it on proper course.
Most of the newer tunnel boring machines studied in this report used
laser guidance systems.
Environmental Control
Dust generation has been one of the most serious environmental problems
associated with tunnel boring machines. This problem has been most
successfully solved by two methods, used either singly or in combination.
One method is to use water sprays near the cutters to reduce the airborne
dust. Controlling the water to these sprays is critical, however, as
too much water will make a slurry of the cuttings while too little
causes the cuttings to become too sticky to handle. The other method is
to isolate the cutterhead with a flexible shroud and evacuate the dust-
laden air from this area with a vacuum system. This air can then be run
through a wet scrubber or exhausted directly from the tunnel.
CASE HISTORIES
Using our definition of hard rock, the entire U.S. experience in this
field reduces to 12 jobs. Approximately one-fourth of these jobs were
definitely not successful; i.e., the machines could not bore the rock
and had to be removed. Another one-fourth were partially successful;
i.e., they could bore the rock, but very slowly. The other one-half
were considered very successful; i.e., the penetration rate, quality of
the opening, and sometimes the cost, were superior to what could have
been accomplished by conventional methods.
The jobs we will be describing are presented in chronological order,
with the earliest being discussed first. Since most of these had
similar muck handling, guidance, and environmental control systems,
these will not be discussed in detail. A summary of all pertinent tun-
nel data and boring machine data for each job is given in tables 1 and
2 at the end of this report.
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The four companies now manufacturing hard rock tunnel -boring machines
in the U.S. are Jarva, Lawrence, Robbins and Calweld. Each of these
companies has manufactured successful hard rock machines. Other U.S.
firms manufacturing tunnel -boring machines, but whose machines have not
been used in what we have defined as hard rock, are the Hughes Tool
Company the Mining Equipment Manufacturing Company (MEMCO) and Dresser
OME.
The first hard rock tunnel bored in the U.S., by our definition, was in
Chicago, in 1956. The project was a 9-ft.-diam sewer tunnel constructed
in limestone with a compressive strength of 18,000-to 25,000-psi. Al-
though information on this job is scarce, we assume that the rock was
the same kind as that in which the present day Chicago sewers are being
constructed.
The mole used on this job was a Robbins model 103 and the fifth one built
by that company. At 17 tons, this was a light machine by today's stan-
dards. The cutterhead was fitted with both disk and drag cutters. This
machine had a thrust of only 110,000 Ib. but had a torque of 138,000 ft.
Ib. This high torque to thrust ratio was probably made necessary by
the drag cutters which require a large tangential force to move them a-
cross a rock surface.
Although the mole achieved an average penetration rate of from 2 to 4
fph, it was not successful because the drag cutters were unsuited to
the hard limestone. The carbide inserts in these cutters were hard
enough to cut the rock, but the bits suffered from excessive shock load-
ing and the inserts could not be kept in their tools. The replacement
of these inserts was a major source of downtime and expense (9j."
Experience gained on this job led to the successful boring of a similar
sewer tunnel in Toronto, Canada, the next year. This mole, also a
Robbins machine, was modified to increase the structural strength, as
well as the torque and thrust capabilities. Probably most important,
the drag cutters were replaced with rolling disk cutters, ihis machine
achieved advance rates of over 100 fpd.
Job No. 2
The next hard rock tunnel was the Richmond water tunnel begun in 1964.
This 12-ft.-diar,i. 5 5-mi.-long tunnel was designed to bring 3CC ,;,;!! ;,,r,
gallons of water daily from Brooklyn to Staten Island.
^Underlined numbers in parentheses refer to itmes in the list of refer-
ences at the end of this report.
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The rock bored was the Manhattan schist which is composed primarily
of quartz with small amounts of feldspar, garnet and muscovite. With
a compressive strength of 25,000 psi, this was the hardest rock attempted
by a tunnel borer up to that time.
The mole used on this job was the prototype Alkirk Hard Rock Tunneler,
model HRT-12, built by Lawrence Manufacturing Co. (Figure 4). This mole
uses the pilot-pull principle. In operation a 17-1/2-in-diam pilot hole
is bored some 9 ft. ahead of the main cutterhead. A gripper and rubber
packer are then expanded to anchor the pilot drill assembly in the hole,
and the hydraulic unit pulls the cutterhead against the face to provide
a portion of the total thrust generated by the machine. The balance of
the thrust is generated by a conventional rib jack and thrust cylinder
arrangement. This pilot drill, in addition to providing thrust, also
serves to keep the mole on course and provides additional stability
while boring. The main cutterhead was dressed with 53 tungsten carbide
button bits and revolved at 9 rpm. The machine had a thrust of 1
millon Ib. and a torque of 250,000 ft. Ib. The estimated cost of this
machine was $500,000, but it was expected to pay for itself from the
reduction in concrete used in the lining because of reduced overbreak.
Although the mole achieved an average penetration rate of 4 fph when
in operation, it was hampered by machine as well as geological problems
for most of the year and required continual adjustment. Just as the
machine was becoming debugged, the cutters failed to perform satis-
factorily. Finally, after one year of effort had achieved only 200 ft.
of tunnel, the mole was pulled off the job and the tunnel was finished
by conventional drill and blast methods.
Despite these difficulties, this machine showed that rock as hard as
25,000 psi could be bored at satisfactory rates of advance with a
mechanical mole.
Job. No. 3
The first hard rock boring success in the U.S. took place at the Re-
public Steel Corp. Adirondack Mine at Mineville, N.Y., in April 1967.
The project was a lO-ft.-diam. inclined shaft, 765 ft. long and with
a slope of 27 degrees.
The rocks encountered on this bore ranged from magnetite ore with a
compressive strength of 10,000 psi through horneblende, biotite gneiss,
and gray granite gneiss. This last rock has a compressive strength of
35,000 psi.
The mole used was a Jarva Mark 11 equipped with tungsten carbide button
and kerf cutters (Figure 5). The penetration rate ranged from 1 to 4
fph and averaged 1.67 fph.
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Although the penetration rate was low and the length of the bore was
short, this was the first success in hard rock boring in the U. S. The
other noteworthy feature of this job was the ability of the machine to
bore on a 27-degree downgrade
Job NO. 4
Job No. 4, the Lawrence Avenue Sewer tunnel (Figure. 6), is being bored
in Chicago, 111. This job began in March 1968 and as of September 1970,
6,760 ft. of 13-ft 8-in.-diam. tunnel and 3,968 ft. of 13-ft. 4-in.-diam.
tunnel had been bored.
The rock being bored is the Niagaran dolomite, a massive, competent,
and dry rock. Our tests at the TCMRC show this rock to have a compres-
sive strength of from 17,000-to 32,000-psi with an average of 27,000 psi.
The first 7,000 ft. of this tunnel was bored with the prototype Alkirk
Miner, the same as was used in the previously mentioned Richmond Water
Tunnel. At the beninning of this project, a number of difficulties
were experienced with this machine including an electrical fire. During
the last 4 months the machine averaged an impressive 1,000 ft./month.
In December 1969, a new Lawrence machine was installed, and by July 1970
it had completed 4,000 ft. of tunnel known as the Harding Avenue Section.
The machine is now working on the remaining 12,670 ft. of the Lawrence
Avenue job.
This second mole has achieved some excellent boring rates, as have the
other two moles working in the Niagaran dolomite (Jobs 8 and 9). Thus,
where conditions are right, even in rock which is quite hard, the exca-
vation rate of tunnel moles has shown steady improvement and holds even
greater potential for the future, primarily because of its continuous
fragmentation system.
Job No. 5
One of the most successful machine-bored hard rock tunnels began in
September 1968 and was completed 9 months later. This was the 20,000 ft.
long River Mountains tunnel driven by Utah Construction and Mining Co.
with a Jarva mole. This 12-ft.-diam tunnel through the River Mountains
was part of the Southern Nevada Water Project, which is designed to
bring water from Lake Mead to Las Vegas and other southern Nevada cities.
The rocks encountered along this bore were primarily extrusive volcanic
rocks of an extremely complex and variable geology, mainly tuffs and
breccias, rhyolite, and rhyodacite. The rhyolites had compressive
strengths of from 3,000-to 10,000-psi and the rhyodacites from 4,000-to
23,000-psi. Over 40 fault zones were crossed during this bore and,
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except for some blocky ground at these faults, they did not present any
great problems. Furthermore, the tunnel was dry along its entire length.
The combination of fairly soft but competent rock and dry conditions
offered nearly perfect conditions for a tunnel boring machine.
The mole used on this project was a Jarva Mark 11-1200 (Figure 7) with
a thrust of 620,000 Ib. and a torque of 170,000 ft. Ib. The cutterhead
was equipped with 30 cutters and rotated at 9.2 rpm. In the hard
rhyolites and rhyodacites, the four gage positions were equipped with
tungsten carbide kerf cutters. The interior cutters were of steel,
either milled tooth or disk type. The fact that the steel cutters could
be used indicates that the majority of the rock must have been fairly
soft. Cutter cost averaged less than $15/lineal ft. of tunnel ($3.60/
cu. yd.), but on stretches where hard rock was unexpectedly encountered,
the soft cutters lasted for only a few feet and raised the cutter cost
to $40/ft. ($9.50/cu. yd.) (8).
The penetration rates on this job varied widely because of the different
rock types encountered. In the hard rhyodacites the penetration averaged
2 fph, and in the softer tuffs it averaged 23 fph. The average penetra-
tion per shift was 33 ft. and per day 110 ft.
The River Mountains tunnel was completed on schedule and cost $90/lineal
ft. ($21.20/cu. yd.), an estimated savings of $50/ft. over conventional
methods (8). This project demonstrates that in a job of reasonable
diameter and length and in favorable conditions (i.e., in dry, fairly
soft but competent rock, even if very hard in sections) a tunnel boring
machine connot be matched for speed or quality of the opening, by con-
ventional excavation methods.
Job No. 6
Probably one of the most difficult tunnel boring projects in the U.S.
was in the Hecla Mining Co. Star Mine at Wallace, Idaho. This job
began in November 1968 and was discontinued a year later after boring
only 437 ft. of tunnel.
The excavation was carried out in the Revette Quartzite Formation, a
hard, brittle, thickly bedded rock with a high silica content. The
reck is very abrasive and tends to be badly fractured along a series
of fracture plane systems. The compressive strength of this rock ranges
from 10,000-to 51,000-psi with an average of 29,000 psi.
While this kind of hard rock was generally not considered economically
boreable, data accumulated during the operation of raise boring equip-
ment at the mine indicated an acceptable cutter life and penetration
rate for a successful boring operation. The machine manufacturer in-
dicated that a penetration rate of 2 to 3.5 fph might be expected (3_).
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The 9-ft.-diam. Jarva mole used on this job was a small machine with
a weight of 30 tons and a correspondingly low thrust and torque of
560,000 Ib. and 132,000 ft. Ib. respectively. The cutterhead was
equipped entirely with tungsten carbide studded cutters.
This mole achieved an average penetration rate of 3.5 fph with a max-
imum rate of 8 fph. However, due to extensive modification of the mole,
coupled with a long supply route, the mole had a very low availability.
The major difficulty on this job was the coarse character of the rock
cuttings. Much of the muck consisted of 6-to 9-in. pieces produced by
failure of the rock along existing fracture planes. These large pieces
damaged the cutters, muck buckets, and drive train of the mole. To re-
duce the size of this muck, a false face was installed on the cutter-
wheel to keep the large blocks from falling from the face until they
could be broken up by subsequent cutter passes. When this attachment
did not work, the decision was made to modify the machine to handle the
large muck (_3_). These modifications were partially successful but did
not solve another serious and costly problem, the failure of the cutters
and cutter bearings.
The bearing seals on the cutters would first deteriorate, which would
allow the abrasive quartzite dust to enter the cutter bearings, causing
them to fail. The gage cutters which had to pass through the muck at
the invert had the shortest life of all and were replaced three times
more often than the interior cutters. Another possible reason for the
short life of the gage cutters is that the gage section of the hole
(outer edge) requires more energy to cut than do the other sections of
the hole. This is true of any tunnel boring job.
The inability of the mole to bore this ground was due to the combination
of blocky and abrasive rock which represents the worst of conditions for
a tunnel boring machine.
It is interesting to note that the problem of the falling rock occurred
only at the face of the tunnel, and once a section was bored the opening
was stable and did not require any support.
Job No. 7
The largest hard rock mole built in the U.S. in terms of weight, horse-
power, and cutterhead diameter, was the well-publicized White Pine ma-
chine manufactured by James S. Robbins Co. (Figure 8). This 260-ton,
1,700-hp, 19-ft.-diam. mole is currently being used to drive development
openings in the White Pine Mine, White Pine, Mi. The first such open-
ing is a 9,000-ft.-long development drift which will connect the No. 3
shaft to the mining front.
This drift is being bored through the Copper Harbor formation which lies
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beneath the ore horizon. This formation is a moderately wet massive
sandstone, with an average compressive strength of 25,000 psi and a
peak strength of 31,000 psi.
During the shakedown period, a number of modifications were made on this
machine. The double-rotating cutterhead was converted to a single-ro-
tating system turning at 4.5 rpm. The center tricone cutter, which
failed because of the low rotational speed, was redesigned to rotate in-
dependently of the main cutterhead and at a much faster speed. The
original roof pinner drills were replaced with pneumatic drills when
they failed to achieve satisfactory penetration rates. Many changes
have also been made in the arrangement of the individual disk cutters
on the cutterhead.
A conveyor was used for muck haulage on this job. The usual trailing
conveyor behind the mole discharged into an extendable, cable-supported,
36-in-wide haulage conveyor. This conveyor was hung by adjustable
chains from 6-in. channel sets bolted on 4-ft. centers on the top of
the tunnel.
This job began in November 1968, and as of July 1969, 961 ft. of tun-
nel had been bored in 373 hours of actual machine operation. The
average penetration rate was 2.6 fph. Total cost per foot of tunnel ,
including labor, electric power, cutters, other materials, and de-
preciation, averaged $125. Cutter costs averaged $30/ft. excluding
the first 290 ft. of tunnel (2).
The latest progress reports show that as of November 1970 the machine
had completed a total of 2,000 ft. of tunnel at a progress rate of 200
to 300 ft./month.
Job No. 8
The next tunnel is known as the Calumet Intercepter Sewer 18-E and is
part of the MSDGC's deep tunnel plan for Chicago, 111. This plan com-
bines storm and sanitary sewer systems and power generation facilities
into one large network. Essentially the combined sewer system is de-
signed so that in periods of storm runoff the mixture of raw sewage and
storm water is stored in underground chambers instead of being released
untreated into the environment.
The Calumet tunnel is 18,000 ft. long and 16 ft. 10 in. in diameter.
This job began in April 1969 and 16,000 ft. had been completed in
September 1970. The rock being bored is the Niagaran dolomite with a
compressive strength of 17,000-to 28,000-psi.
The Jarva Mark 21 mole being used on this job (Figure 9) has a thrust
of 2,100,000 Ib. (the largest thrust of any hard rock mole to date) and
a torque of 890,000 ft. Ib. The cutterhead was equipped with tungsten
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carbide insert disk cutters.
This mole achieved an average penetration rate of 6 fph and an average
footage per shift of 27 ft. The availability of this machine was 50%.
The cutter cost per foot of tunnel was $50, and the machine cost was
slightly over $1 million.
The bored surface of this tunnel was of such excellent quality that no
final concrete lining will be necessary. This will result in a consider-
able savings in the total cost of the tunnel.
Job No. 9
Another deep tunnel sewer project for MSDGC is the Southwest Intercep-
ter Sewer ISA, 17,553 ft. long and 13 ft. 10 in. in diameter. This
tunnel is being bored in hard limestone with a compressive strength of
15,000-to 24,900-psi. This project began in 1969 and was completed
in September 1970, some 4 months ahead of schedule.
The mole used on this job was a Robbins with a thrust of 890,000 Ib.
The cutterhead was equipped with 27 disk cutters with a center tricone
cutter.
The average penetration rate was 5.5 fph.
The bore of this tunnel, like that of job No. 8, will not need the final
concrete lining.
Job No. 10
Another hard rock tunnel being bored at an underground metal mine is at
the Magma Copper Mine, Superior, Ariz. This 12-l/2-ft.-diam. tunnel
will be used as a haulageway. This operation began in September 1969,
and 6,031 ft. of the total 9,400 ft. had been bored as of October 1970.
The rocks encountered were dacite with a compressive strength of up to
30,000 psi, and quartzite with a compressive strength of 49,000 psi.
Although in most of the bore the rock is competent and stands without
support, occasional loose rock, faults, and cavities have slowed progress.
The Lawrence mole used on this job is similar to the other Lawrence moles
already described with a thrust of 1,500,000 Ib., a torque of 450,000
ft. Ib., and a rotary speed of 9 rpm. The cutterhead was equipped with
disk cutters which have tungsten carbide buttons mounted on the cutting
edge.
Initial operation with this machine brought out some difficulties with
the laser beam guidance systems, but these have since been solved. The
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most serious problems on this job have been geologic hazards such as bad
roof conditions, faults and cavities. These conditions delayed progress
until they could be stabilized with roof bolts, grout and shotcrete.
During this bore, a 200-ft.-long section of very hard quartzite (49,000
psi compressive strength) was encountered. This hard abrasive rock was
difficult to bore, and the penetration rate fell to 1 fph. Cutter life
was also very poor in this section, and a number of cutter changes were
necessary before it was successfully completed.
In spite of these difficulties, however, the average penetration rate has
been (?.2 fph. The best month's advance was 850 ft. and the average
monthly advance was about 650 ft.
Job No. 11
In January 1970, the Climax Molybdenum Mine at Climax, Colo, began
boring a 13-l/2-ft.-diam haulage drift on the 600 level with a Calweld
hard rock mole. This is the first hard rock machine produced by Calweld
(Figure 10).
The rock being bored is a quartz monzonite porphyry with a high fracture
density. Our laboratory tests gave an average compressive strength of
only 5,700 psi. This low strength was caused by numerous fracture sur-
faces which ran at an angle to the long axis of the core and along which
the core was prone to separate. Since other sources give the strength
of this rock at 16,000-to 28,000-psi, it meets our definition of hard
rock.
The mole has a thrust of 1 million Ib. and a torque of 347,000 ft. Ib.
The 24-in.-diam tricone bit in the center of the cutterhead rotates at
25 rpm, and the outer section, equipped with 16 tungsten carbide button
cutters, rotates at 8 rpm.
The rocks being bored are primarily argillites along with some volcanics
and conglomerates. The argillites have a compressive strength of up to
35,000 psi.
The Lawrence mole used on this job has 600 hp available to drive the
cutterhead (Figure 11). The cutterhead rotates at 9 rpm and is equipped
with tungsten carbide studded disk cutters.
The mole has averaged 5 ft./hr. and completed 75 ft. on the best day.
Total footage bored as of October 3, 1970, was 3,500 ft.
Subsequent to the presentation of this paper, this mole was pulled off
the job after completing some 6,000 ft. of tunnel. This action was
reportedly taken because of low penetration rates and excessive main-
tenance requirements. Both of these problems were probably a direct
-------
result of the very hard rock being bored, now estimated to be in the
35,000-to 40,000-psi range.
SUMMARY
PERFORMANCE DATA
Penetration Rates
The instantaneous boring rates of tunneling machines in hard rock show
a remarkable similarity regardless of the tunnel diameter or rock type.
The machines studied in this report have achieved instantaneous boring
rates ranging from 1 to 6 fph with an overall average of from 3 to 4 fph.
In the hard abrasive rocks, such as quartzite or sandstone, the average
penetration rates are lower than for the less abrasive rocks, such as
limestone or dolomites, because of increased maintenance requirements
due to increased cutter and machine wear. Using a figure of 50% as the
average availability of these machines, a rate of about 20 ft./shift is
average. The maximum footage in hard rock is about 1,500 ft./month.
Boreability
The most successful hard rock boring was done in nonabrasive rock such
as limestone, dolomite and dacite, with average compressive strengths
of less than 30,000 psi. Rocks with strengths of up to 50,000 psi have
been bored, but only for short distances. The upper limit of economic
boreability in most rocks is 30,000 psi compressive strength. All hard
rock tunnels to date have been in the 9-to 13-ft. range.
Cost
Cost data were extremely variable because of the large differences in
rock strength, rock abrasiveness, labor, size of job, etc. What little
cost data were available showed direct tunnel excavation costs to be
between SI3 and S38/cu. yd. of material excavated with an overall aver-
age of $27.
While cutter costs were rarely given, they formed a substantial part
of this excavation cost. Cutter costs given by machine manufacturers
ranged from $3 to $9.50/cu. yd. of material excavated with an overall
average of $6.30.
Capital cost was also a major cost factor in tunneling. Since the
machines are essentially custom made, they must be amortized over the
length of a single project. Capital cost can be roughly estimated at
either $1,000/hp or $50,000 times the cutterhead diameter in feet (1_0).
-------
For Jarva Moles the first method gives the best cost estimate.
Energy Efficiency
The efficiency of a fragmentation process is usually determined by a
parameter known as specific energy. Specific energy is the energy re-
quired to break out a unit volume of rock. The units we used were Ib.
in./in.3 or after cancelling terms Ib./in.2 (psi). To calculate this
parameter we used the manufacturer's specification for torque and rotary
speed along with the instantaneous penetration rate. To avoid the neces-
sity of conversion factors in the formula, torque was given in (in. Ib.),
radius in (in.), and the penetration rate in (in./min.). The formula
used was as follows:
Specific Energy = torque x rpm x 2^
TT x radius^ x penetration rate
The specific energy for eight of the 11 tunnels investigated ranged
from 9,400-to 17,250-psi with an overall average of 14,325 psi. The
ratio of specific energy to compressive strength for these same eight
jobs ranged from 0.37 to 0.72 with an overall average of 0.54. Thus
for the majority of tunnels investigated, the average specific energy
was approximately 54% of the compressive strength of the rock being
bored. This value agrees with those ralculated by other researchers.
Quality of the Opening
The quality of the machine-bored openings were in most cases very good:
i.e., they were on proper line and grade, had little overbreak (5% or
less}, and were stable. Undoubtedly the fact that the tunnels were
driven in hard rock largely accounts for the stability of the openings,
but where a comparison could be made with conventional methods, the
bored opening was always the most stable. Of all the tunnels bored in
hard rock, over half required little or no support, while the rest re-
quired only minor roof bolting and shotcreting.
The most outstanding examples of this were the MSDGC sewer tunnels in
Chicago (Job Nos. 8 and 9) where the quality of the opening was so good
that no final concrete lining will be necessary. The smooth rock sur-
face, with a compressive strength of 15,000-to 28,000-psi, is far
stronger than the best concrete lining would be. The elimination of
these linings will result in a significant savings in construction costs
for these tunnels.
INADEQUACIES IN MACHINE BORING
From the case histories already described, it is apparent that while
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the tunnel boring machine has made notable advances in both the speed
of boring and the ability to bore increasingly harder rock, there are
many areas where improvements are needed. To summarize the U.S. ex-
perience with machine boring, we will use some of the findings of the
OECD Advisory Conference on tunneling (£).
From over 600 replies to a questionnaire on tunneling, the most serious
deficiencies of tunnel boring machines (in order of importance) were
(1) higher cutter costs, (2) the lack of flexibility in meeting changing
rock conditions, (3) the low reliability of the machines, (4) the in-
ability to bore hard rock, (5) the lack of an integrated support sub-
system, (6) the inability to bore other than a single-size circular-
shaped tunnel, (7) the large bulky size of the machines, and (8) the
poor maneuverability of the machines.
High cutter cost and frequent bearing failures were listed as the most
serious deficiencies, especially in hard abrasive rock. Cutters, bear-
ings, and seals were criticized for both poor design and poor materials.
Bearing failure was aggravated by lubrication problems and poor seals
which failed to keep out contaminants. We also recognized that several
million dollars a year in research are being spent by the oil well drill-
ing industry to improve cutters and seals and this research will continue
to provide steady improvement in this area. The inability to sense
cutter failure and the difficulty in changing cutters also complicated
the problem. The deficiencies are even more serious in hard abrasive
rock where the cutter cost is the key to the success or failure of a
project. While absolute costs are difficult to give, one can generally
assume that at present TBM's are uneconomical in rock of over 30,000
psi compressive strength.
The lack'of flexibility to operate successfully in a variety of conditions
such as in changing rock hardness, in a mixed face, in the presence of
large amounts of water, and in blocky squeezing ground, was cited as a
serious deficiency. Thus, in bad ground or where rock conditions were
in doubt, the more reliable drill and blast method was preferred.
Tunnel boring machines were also cited as having a low reliability
because of frequent mechanical failures, excessive maintenance require-
ments, and the need for frequent cutter changes. All of these problems
were further compounded by the poor accessibility to the critical parts
of the machine. A survey of hard rock jobs shows that an availability
of 50&o is about average.
High capital cost was another often-mentioned disadvantage of tunnel
boring. As already mentioned, cost can be estimated at $1 ,000/hp or
$50,000 times the cutterhead diameter. Using these estimates, a tunnel
boring machine will cost two or more times as much as conventional tun-
nel driving equipment. Since, in most cases, the cost of the machine
must be written off on one job, tunnels of less than 1 or 2 miles, de-
pending on tunnel diameter, are doubtful projects. With used machines
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becoming available, however, this restriction does not automatically
apply 00).
The inability of tunnel boring machines to bore hard rock without exces-
sive cutter costs was another major criticism of this method. This
factor has been discussed under cutter cost. Tunnel boring machines are
attempting harder and harder rock, and today's hard rock job will be
performed easily in the future. At present the upper limit of bore-
ability is approximately 30,000 psi, although for short distances rocks
of 50,000 psi have been bored. Much also depends on the abrasiveness
of the rock. The more abrasive the rock, and by this we generally mean
the quartz content, the more expensive and harder to bore.
The machines were also found difficult to maneuver and could not be made
to negotiate sharp changes in line or grade. While some machines have
successfully bored on grades of 27 degrees and some are able to bore
curves with a minimum radius of six times the tunnel diameter, most are
limited to boring a minimum radius of 10 to 20 times the diameter of the
machine. The bulkiness of the machines is also criticized, especially
in small-diameter tunnels. Such tunnels do not offer enough room to
perform maintenance or repair work on the machines. This fact prevents
IBM's beiny u^ed in tunnels less than 80 in. in diameter (10).
The last major criticism or deficiency noted was the lack of an integrat-
ed support system to hold the ground as the machine is advanced. Many
machines now have a small shield behind the cutterhead to give imme-
ciate support and some have roof drills behind the cutterhead to install
roof bolts if necessary. Many industry people feel that a machine cap-
able of applying a thin coat of shotcrete to the tunnel roof as the
machine is advanced would provide good temporary support.
RAPID EXCAVATION—THE FUTURE
The recent OECD Advisory Conference on Tunnelling in its Report on
Tunnelling Demand (5) indicates that an estimated total of about 188,000
mi. of hard-rock tunnels with an excavated volume of about 4.4 billion
cu. yd. are expected to be built during this decade in the 18 reporting
OECD nations. This figure represents a 450% increase in length and a
210% increase in volume over hard-rock tunneling in the past decade.
These projections demonstrate the needs facing those engaged in frag-
mentation of hard rock. Significant increases in tunnel construction
will confront those persons directly concerned with utilities, novel
underground structures, rapid transit tunnels, and underground parking.
Only in hydroelectric-power generation are these needs expected to
decrease.
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SATISFYING THE DEMAND
With demands for hard-rock excavation of the magnitude mentioned facing
us during the 1970's, it is apparent that new sophisticated techniques
must be used to supplant or improve on those historically applied.
Conventional tunneling must give way to various forms of continuous
fragmentation—a new generation of tunnel boring machines.
Novel Methods
Although the tunnel borer in its familiar form is expected to dominate
the scene, new hybrid excavators will make their debut. In the eary
seventies we can look for a combination of mechanical and hydraulic
fragmentation using powerful continuous jets or water cannons. Plans
for such a machine are already advanced and cooperation between Exotech
and the Calweld Division of Smith International, among others, may
speed the process of this concept from design, development, and testing
to an actual application.
In addition, entirely new concepts for tunnel boring may be applied
later in the seventies after a suitable gestation period. Continuous
rapid fire ballistic systems may satisfy the energy requirements for
breaking hard rocks at high rates of advance. Thermal or electrical
methods using stresses induced by lasers, plasma jets, microwave heating,
and dielectric or induction heating, alone or in combination with other
methods, may revolutionize the state of the art. Not to be overlooked
is the potential of sonic energy. Chemical reagents may be applied to
assist the mechanical fragmentation process in specific situations. All
this speculation has been directed toward the rock breakage process. No
attention has been paid to the total system concept.
Daring Innovation
These methods of gragmenting rock are not necessarily "far out" or
"blue sky." Most have their roots in antiquity as described by Georguis
Agricola in De Re Metallica (]_). The challenge will be for modern
engineering to tame the awesome forces involved as needed to speed the
job of excavation. Operators, contractors, owners, and manufacturers
will be called on to make increasingly daring attempts with unfamiliar
equipment and to face the attendant problems.
PROBLEMS WHICH MUST BE ANTICIPATED
The diffuculties imposed by the subsurface environment will not be new
to the tunnel experts. The greatest difficulty may be to impress these
constraints on people unfamiliar with the environmental problems of
inner space. But after all, the hostile environment of outer space was
even more formidable, and has not proved insurmountable. The technology
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of outer space must be brought to bear on the problems of Inner space--
the hidden dimension.
Health and Safety
All fragmentation systems have certain common basic requirements. The
opening must be supported or self-supporting to prevent injury or equip-
ment damage from fall-of-ground. If rapid methods of tunneling are
developed, the support subsystem must receive commensurate attention so
that it is compatible in every respect. The system for support erection
must be safe, as well as speedy.
Workmen and equipment must be protected from flooding, which has account-
ed for a myriad of difficulties in the past decade. The dewatering sub-
system must be compatible with the primary system of fragmentation. A
hydraulic fragmentation system would require a compatible dewatering
subsystem which might serve double duty as a materials handling system,
to remove muck in slurry form.
Temperature and air quality in the working area must be maintained at
levels compatible with good health and efficient functioning. Systems
employing thermal stressing may require a novel air-conditions sub-
system or the application of space suit techno!goy.
e
The rapid pace of excavation will, in some cases, require high-speed
underground systems for materials handling. Designers striving for
rapid removal of muck and rapid delivery of supplies must put safety
first.
Good visibility is extremely important for safe, efficient operations.
Novel systems may create dust, mist, or haze which, if not controlled,
will add serious constraints to these systems.
Present-day problems which can guide future systems engineers include
the congestion often encountered on tunneling jobs. Equipment im-
provement should consider more compact, lighter weight equipment. Any
equipment proposed for underground use must overcome the problems of
hostile environment which renders much present-day equipment unsuitable
for use underground.
Experience during the past decade has shown that it is particularly
important to be able to predict potential changes in rock conditions
before they are actually encountered. The rock conditions dictate
the ground-support requirements. Excessive water and major faults
may bring excavation to a sudden halt. Either rapid boring systems
must be designed with adequate flexibility to cope with severe changes
in conditions or sensing equipment must be developed which is capable
of predicting conditions far ahead of the advancing face.
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high noise levels reduce worker efficiency, impede effective communica-
tion, and if intense enough, cause permanent damage to the ears. For
many novel systems, this problem deserved immediate and serious atten-
tion. Health and safety constraints, if not considered at an early
stage of equipment development, could easily spell failure for an other-
wise promising fragmentation system.
Electrical accidents are all too common, and electrical systems should
be examined closely for shock and fire hazards. A small underground
fire often has disastrous consequences, and tunnel boring operations of
today have not been exempted from these types of disasters. Only care-
ful and imaginative engineering will provide a desirable and complete
rapid excavation system.
=10
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Forward Thrust Cylinders
Muck Bucket
Cutter
Support Leg
Torque Arms
Hydraulic Pump Motor
Bearing Housing
Torque Arm
Electric Meter Panel
Hydraulic Controls-
Main Frame
A Jarva Tunnel Boring Machine Showing Important Machine Features,
(Courtesy, Petroleum and Mining Div., G. W. Murphy Industries)
Fig. 1
TT
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Step 1: Start of boring cycle. Machine clamped,
rear support legs retracted.
Step 2: End of boring cycle. Machine clamped,
head extended, rear support legs retracted.
Step 3: Start of reset cycle. Machine undamped,
rear support legs extended.
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^
The Basic Operating Cycle of a Tunnel Boring Machine.
(Courtesy, Petroleum and Mining Div., G. W. Murphy Industries)
Fig. 2
211
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Right View Shows a Reed QC Tungsten Carbide Button Cutter Used
in Very Hard Rock. Left View Shows a Reed QKC Tungsten Carbide
Kerf Cutter Used in Medium Hard Rock. (Courtesy, Petroleum and
Mining Div., G.W. Murphy Industries)
Fig. 3
The 12-Ft.-Diameter Alkirk Hard Rock Tunneler Used on the Rich-
mond Water Tunnel, New York, N.Y. (Courtesy, Lawrence Mfg. Co.)
Fig. 4
212
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The 10-Ft.-Diameter Jarva Mark 11 Mole Used at the Adirondack
Mine, Mineville, N.Y. (Courtesy, Petroleum and Mining Div.,
G. W. Murphy Industries)
Fig. 5
The 13-1/3 Ft.-Diameter Lawrence Ave. Sewer Tunnel, Chicago, 111
(Courtesy, Lawrence Mfg. Co.)
Fig. 6
213
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The 12-Ft.-Diameter Jarva Mark 11 Mole and Trailing Conveyor
Used on the River Mountains Tunnel, Henderson, Nev. (Courtesy,
Bureau of Reclamation)
The 18-Ft.-Diameter Robbins Mole Used at the White Pine Mine, Fig. 8
White Pine, Mich. (Courtesy, James S. Robbins and Assoc., Inc.
-------
The 17-Ft.-Diameter Jarva Mark 21 Mole Used on the Calumet
Intercepter Sewer 18E, Chicago, 111. (Courtesy, Petroleum and
Mining Div., G. W. Murphy Industries
„-
The 1 3-1/2-Ft.-Diameter Calweld Hard Rock Mole Used at the
Climax, Colo. (Courtesy, CALWELD, Div. of Smith Internatnonal ,
Inc.)
Fig. 9
Fig. 10
215
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An 13-1/2-Ft.-Diameter Alkirk Hard Rock Mole Similar to That
Used on the Dorchester Water Tunnel, Boston, Mass., the Lawrence
Ave. Sewer Tunnel, Chicago, 111., and the Magma Mine, Superior
AHz. (Courtesy, Lawrence Mfg. Co.
Fig. 11
..,n»l Data for Hard Rock Tunnel Boring Projects
—
.
i
-
5
6
-
8
9
10
11
12
i on .
Sewer lunnel, ChicaRO,
tt*ly
New Vr: • ->rp.
and Morrison Knudsen Co.
Mir.e, Minevill'e, Sew Yort
Republic ' eel fqrp.
Laurence Avenue Stf.-er No. I,
Ch i cacc .
J. McHugh. Healv and K.enn.
River Mpunta-;is .unnel,
Henderson, Nevada.
Construction and ynning Co.
Development Drif' - S'ar
Nine. Wallace, Idaho
Hecla Mining Co.
Development Drifi - Uh
Cont inuinji
Jan. 19-0
CO
MarcS 1970
to
Diarceter
9 f.
12 f
9 ft
18 f'
10 in
13 fc 10 In
13 fi 6 in
12 ft 6 in
I ensth.
25,000
25,000
20,000
500
9,000
18,320
17,553
9,400
variable
33,000
limestone
y.a--n*?t i - 1- ,
t nde ,
Gneiss
Tuffs,
te ,
Rhvodacite
O^jar-^
Sandstone
Dolooifc
Limestone
Limestone
Limestone,
Ousrtiite
Quartz
Monzo'
Porohvrv
-es ,
Volcanics ,
Ccingloaerates
-.ompressive
25.000
25,000
10,000
to
35,000
18,000
32.000
3,000
to
23,000
29,000
25,000
to
31,000
'
to
29,000
15,000
to
25.000
12,000
to
49.000
U.OOO
to
28.000
35,000
Kate,
fph
2 to 4
3 to 5.S
10
4
2.6
b
5.5
4 to 5
5
Be low
Surface, ft
220
300
-,300
1,900
220
200 to 235
500
600
230
H::ppcr •
None
None
rol s
Some Rock
None
None
Channel on
4 ft centers
None
None
Some Rock
Bolts and
5hot«c«te
Steel Sets
and
Laecine
Waier
Inflow
None
i
100 apm
None
None
Moderate
300 gptn
Table 1
216
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TABLE 2. - Boring Machine Data for Hard Rock Tunnel Boring Projects
Job
No.
1
2
3
4
5
6
7
8
9
10
11
12
Pro ject -' and
Location
Sewer Tunnel,
Chicago, 111.
Richmond Water
Tunnel ,
New York, N. Y.
Inclined Shaft -
Adirondack Mine ,
Mineville, New York
Lawrence Avenue
Sewer No. 1 ..
Chicago, 111.
River Mountains
Tunnels ,
Henderson, Nevada
Development Drift -
Star Mine,
Wallace, Idaho
Development Drift -
White Pine Mine,
White Pine, Mich.
Calumet Intercept
Sewer 18-E,
Chicago, 111.
Southwest Sewer
13-A, Chicago, 111.
Development Drift -
Magma Mine, Superior
Arizona
Development Drifts -
Climax Molybdenum
Mine, Climax, Colo.
Dorchester Water
Tunnel ,
Boston, Mass.
Bori ng
Machine
bobbins
Model 103
jawrence
iRT-12
Jarva
Mark 11
Lawrence
HKT-13
Jarva
Mark 11
Jarva
Mark 8
Robbins
Moddel 181
Jarva
Mark 21
Robbins
Lawrence
HRT-12
Calweld
Lawrence
Power ,
liP
400
720
440
600 on
Cutterhead
340
330
1,700
1,075
600
600 on
Cutterhead
800
600 on
Cutterhead
Wei ght ,
tons
17
71
45
65
30
260
215
92
Torque ,
ft: Ib
138,000
250,000
235,000
1,500,000
170,000
132,000
1,500,000
890,000
450,000
430,000
450,000
Thrust,
Ib
117,000
1,000,000
1,100,000
450,000
1,100,000
560,000
1,500,000
2,100,000
890,000
1,500,000
1,: 28, 000
1,500,000
Rotational
Speed , rpra
8.2
9
9.2
9
9.3
11.5
4.5
9
8
9
Cutter
Type
Robbins
Disk and
Drag
Carbide
Button
Reed
QC and QKC
Lawrence
Carbide
Disk
Reed
QK and QKC
Reed
QC
Robbins
Disk
Reed
QK
Robbins
Disk
Lawrence
Carbide
Disk
Smith
Carbide
Button
Lawrence
Disk
-o
See Table 1 - For Contractor or Mining Co.
Table 2
76
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ILLUSTRATION
Fig. Page
i i. !*••. . i Of* —
1. A Jarva Tunnel Boring Machine showing important machine
features 70
2. The basic operating cycle of a tunnel boring machine 70
3. A tungsten carbide kerf cutter used in a medium hard rock and 71
a tungsten carbide button cutter used in very hard rock . .
4. The 12-foot-diameter A!kirk Hard Rock Mole used on the
Richmond Water Tunnel, New York, N.Y 71
5. The 10-foot-diameter Jarva Mark 11 Mole used at the
Adirondack Mine, Mineville, New York 72
6. The 13-1/3-foot-diameter Lawrence Avenue Sewer Tunnel,
Chicago, Illinois 72
7. The 12-foot-diameter Jarva Mark 11 Mole and trailing con-
veyor used on the River Mountains Tunnel, Henderson, Nev . . 73
8. The 18-foot-diameter Robbins Mole used at the White Pine
Mine, White Pine, Mich 73
9. The 17-foot-diameter Jarva Mark 21 Mole used on the Calumet
Intercepter Sewer 18E, Chicago, 111 74
10. The 13-1/2-foot-diameter Calweld Hard Rock Mole used at the
Climax Molybdenum Mine, Climax, Colo 74
11. An 18-1/2-foot-diameter Alkirk Hard Rock Mole similar to
that used on the Dorchester Water Tunnel, Boston, Mass.,
the Lawrence Avenue Sewer Tunnel, Chicago, 111., and the
Magma Mine, Superior, Ariz 75
TABLES
1. Tunnel data for hard rock tunnel boring projects 75
2. Boring machine data for hard rock tunnel boring projects ... 75
218
-------
REFERENCES
1. Agricola, Georius, De Re Metallica, Translated from the first
Latin Edition of 1556 by H. C. Hoover, and L. H. Hoover, 1950,
Dover Publications, Inc., New York, N.Y.
2. Garfield, L. A. Tunnel and Shaft Boring at White Pine. SME Fall
Meeting, Salt Lake City, Utah, September 1969, Preprint No. 69-AU-
363, 12 pp.
3. Hendricks, R. S. Hecla Mining Company Case Study - Raise Boring,
Shotcreting, Tunnel Boring. Proceedings of the 2nd Symposium on
Rapid Excavation, Sacramento, California, October 16-17, 1969, 11 pp,
4. Worrell, Roger J., William E. Bruce and David A. Larson. Tunnel
Boring Technology-Disk Cutter Experiments in Sedimentary and
Metamorphic Rocks, BuMines Rept. of Inv. 7410, July 1970, 32 pp.
5. Organization for Economic Corporation and Development. Advisory
Conference on Tunnelling Demand--!960-1980, Washington, D. C.,
June 22-26, 1970, 160 pp.
6. Organization for Economic Cooperation and Development. Advisory
Conference on Tunneling, Report on Hard Rock Tunneling, Washington,
D. C., June 22-26, 1970, 32 pp.
7. Peterson, Carl R. Rolling-Cutter Forces. Proc. 4th Conf. Drilling
and Rock Mechanics, Austin, Texas, AIME Paper No. SPE 2393,
January 14-15, 1969, 10 pp.
8. Sperry, P.E. River Mountains Tunnel. Proceedings of the 2nd
Symposium on Rapid Excavation, Sacramento, California, October
16-17, 1969, 12 pp.
9. Tunnel Boring Through Harder Rocks. Engineering and Mining Journal
v. 161, No. 3, March 1960, pp. 86-90.
10. Williamson, T. N. Tunneling Machines of Today and Tomorrow.
Presented to the Highway Research Board, National Academy of
Sciences - National Research Council, Washington, D. C.,
January 14, 1970, 14 pp.
-------
ACKNOWLEDGMENTS
This Institute was undertaken and implemented thrcugh the
joint efforts of The University of Wisconsin, The United
States Department of the Interior and The Environmental
Protection Agency.
Acknowledgment is made to Mrs. Barbara June Price and other
members of the Environmental Agency staff for the completion
of these papers.
221
U.S. GOVERNMENT PRINTING OFFICE: 1972 484-483/78 1
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