Geo Technical Investigation Volume 1

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Coffey Geotechnics Inc.351 Steelcase Road West, Unit 10, Markham, ON L3R 4H9 Canada

REPORT ON

GEOTECHNICAL INVESTIGATIONDUFFIN CREEK WPCP OUTFALL

VOLUME 1

FACTUAL DATA

The Regional Municipality of DurhamWorks Department605 Rossland Road East, Level 5PO Box 623Whitby, ON L1N 6A3

GEOTMARK00171AAJune, 2012

Distribution:

4 copies CH2M HILL, Daniel Olsen, P.Eng.

1 copy Coffey Geotechnics


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CONTENTS

Coffey GeotechnicsGEOTMARK00171AAJune, 2012

i

FACTUAL REPORT ON GEOTECHNICAL INVESTIGATION 11 INTRODUCTION 11.1 Project Background, Overview 21.2 Description of Site and Regional Geology 21.3 Scope and Method of Investigation 31.3.1 Exploratory Drilling 31.3.2 Laboratory Testing 51.3.3 Geophysical Survey 51.4 Summarized Stratigraphy 51.5 Detailed Description of the Deposits 61.5.1 Overburden 61.5.1.1 Sandy Silt 61.5.1.2 Organic Silt 61.5.1.3 Silt 61.5.1.4 Clayey Silt 71.5.1.5 Silty Clay 71.5.1.6

Sand 7

1.5.1.7 Sand and Silt Till 71.5.1.8 Sand and Gravel 71.5.2 Bedrock (General) 71.5.2.1 Whitby Formation 81.5.2.2 Lindsay Formation 111.6 Environmental and Chemical Soil and Bedrock Quality Testing 151.6.1 Environmental Testing 151.6.2 Chemical Testing 191.7 Statement of Limi tations 19

List of References


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CONTENTS


ii

Appendices

Appendix A: Drawings (1-12)

Appendix B: Borehole Logs

Appendix C: Laboratory Test Results (Soils)

Appendix D: Tables

Appendix E: Photographs of Rock Cores

Appendix F: Environmental Test Results

Appendix G: Geophysical Report


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Report on Geotechnical Investigation Duffin Creek Water Pollution Control Plant Outfall - Volume 1


1

FACTUAL REPORT ON GEOTECHNICAL INVESTIGATION

DUFFIN CREEK WATER POLLUTION CONTROL PLANT OUTFALLTHE REGIONAL MUNICIPALITY OF DURHAM

Volume1

1 INTRODUCTION

Coffey Geotechnics Inc. (Coffey) was retained by the Regional Municipalities of Durham and York (the

Regions) to carry out a geotechnical investigation and to prepare a geotechnical report for a new potential

Duffin Creek Water Pollution Control Plant (WPCP) Outfall. The work was carried out in general agreementwith the Terms of Reference dated February 22, 2010, prepared by the Regions and Coffeys Proposal

P-10.030 dated March 11, 2010. Authorization for the investigation was contained in the Agreement for

Professional Consulting Services dated July 9, 2010 (Agreement Number CA-2010-10).

The purpose of the geotechnical investigation is to characterize the lake bottom soil and bedrock conditions

at eleven (11) off-shore borehole locations, and to provide geotechnical input for the environmental

assessment (EA) of the potential outfall. Investigation of the land portion of the project (e.g. a potential

shaft) is not included in this report. During the detail design stage it is proposed that a borehole or

boreholes be drilled on land and at the shaft location.

The results of the off-shore investigation are presented in a report consisting of two volumes. In this

volume, Volume 1, the factual information generated by the investigation is presented. In particular,Volume 1 briefly describes the nature of the project, the site and the geology, the scope and method of the

investigation. It then describes the lake bottom conditions and the bedrock formations encountered in the

boreholes. Appended to Volume 1 are the borehole log sheets, and the results of the field and laboratory

tests.

In Volume 2, the factual data is interpreted as relevant to the geotechnical design and construction of the

project.

It is noted that the reported soil and rock conditions are known only at the relatively widely spaced (250 m

to 500 m) borehole locations and that variations in the properties of the deposits can be expected between

the boreholes.


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VOLUME 1

FACTUAL DATA

1.1 Project Background, Overview

The Duffin Creek WPCP is located at 901 McKay Road in the City of Pickering. The WPCP is jointly owned

by the Regions of Durham and York and is operated by Durham. To meet the growing demand, the

Regions plan to increase the present 420 MLD process capacity of the plant to 630 MLD. Since this

expansion of the process capacity exceeds the 560 MLD hydraulic capacity of the existing outfall, the

construction of a new outfall pipe may become necessary. The Schedule C Class Environmental

Assessment (EA), currently being undertaken by CH2M Hill Canada Limited (CH2M), tentatively concluded

that the new outfall should be a 3600 mm I.D. pipe reaching into the lake a maximum distance of 3000 m.

The investigation described in this report is in support of the Class EA.

The potential Duffin Creek WPCP Outfall would be located on the shoreline of Lake Ontario from where the

outfall pipe would extend perpendicularly for a maximum distance of approximately 3000 m into Lake

Ontario. The new outfall alignment would be roughly parallel to the existing outfall and would be about

200 m to 300 m to the east of it.

The purpose of the present investigation is to characterize the geotechnical conditions for the offshore

portion of the outfall between the shoreline and the diffuser to be located a maximum of 3000 m offshore,

where the water depth exceeds 20 m. Presently, two options for construction are being considered: a deep

concrete lined rock tunnel or a concrete pipe placed in a dredged trench at lake bottom.

1.2 Descr ipt ion of Site and Regional GeologyThe project site is located in Lake Ontario on the shore of which the Duffin Creek WPCP is located.

Immediately to the west is the Pickering Nuclear Generating Station, while to the east is the estuary of the

Duffin Creek. Further along the shoreline, both to the west and to the east are park lands beyond which are

residential subdivisions.

The City of Pickering is located in the physiographical region of the Iroquois Plain along the north shore of

Lake Ontario and is bordered in the north by the south slope of the Oak Ridges Moraine. The abandoned

old shoreline of post-glacial Lake Iroquois, formed as the last glaciers withdrew from the region about

10,000 years ago, lies about 10 km inland from the present Lake Ontario shoreline. The wave-washed

Iroquois Plain is characterized by gently rolling, bevelled till plains with flat sand and clay plain areas that

formed as lake bed deposits in Lake Iroquois. Deeply eroded stream valleys of the Rouge River and Duffin

Creek provide the largest relief in the region.

Upper Ordovician sedimentary rocks of the Whitby and Lindsay Formations underlie the region. The Whitby

formation is grey and black shale and the older Lindsay Formation is a grey limestone with thin shale

interbeds.


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Shales of the Whitby Formation are generally medium strong, moderately fissile, and are of medium

durability. They are thinly bedded with two sets of nearly vertical joints[9]

. The rock comprises three

members of which the lowest (oldest) often contains organic gases.

The limestone of the Lindsay Formation is fine grained, fossiliferous, and massively bedded with thin shaley

interbeds throughout. It too contains pockets of gas.

1.3 Scope and Method of Investigation

1.3.1 Exploratory Drilling

The field work was undertaken between July 7 and August 25, 2010, and between July 27 and August 23,

2011 and consisted of extending eleven (11) boreholes to depths ranging between 49 m and 29 m below

lakebed. The drilling was carried out from a drilling platform consisting of a 25 m x 12 m jack-up barge with

hydraulically operated spuds that made it possible to work in waters up to 22 m deep while elevating the

platform out of the water to provide the required static conditions for rock coring. The barge was owned

and operated by McKeil Marine Limited, working under contract to Canadian Soil Drilling Inc. The drilling

work was subcontracted to Canadian Soil Drilling Inc. (CSD). CSD provided a truck mounted, hydraulically

operated drill rig (CME 75) equipped for soil sampling and rock coring. The positioning of the barge and

drill rig over the pre-determined borehole locations was done using a Global Positioning System (GPS) with

an accuracy of 5 m. The approximate borehole locations with their UTM (NAD 83) coordinates are shown

on Drawing 1 in Appendix A, and on the individual borehole logs in Appendix B.

Sampling of the unconsolidated lakebed deposits overlying the bedrock was effected by the standard

penetration test method (ASTM D1586-84) at 0.75 m intervals to 6 m below lake bottom and then at 1.5 m

intervals at greater depths. Through the overburden, the boreholes were advanced by rotary mud drilling

using tri-cone roller drilling bits with tungsten carbide inserts. PWT (127 mm I.D) casing was used to

stabilize the borehole walls within the overburden.

Sampling of the bedrock was by diamond core drilling, using a 1.5 m long HQ3 triple tube wireline core

barrel providing 61 mm diameter rock core samples. HWT (102 mm I.D.) casing was lowered inside the

larger PWT casing and sealed into the bedrock prior to rock coring. The recovered rock cores were visually

examined and described in the field. In addition, the following index properties were noted and recorded:

Total Core Recovery (TCR);

Solid Core Recovery (SCR);

Rock Quality Designation (RQD);

Fractured Index (FI);

Percent of Hard Layers (HL);

The locations and thicknesses of the hard layers were also recorded.

The meaning of these terms is given in the Explanation of Terms Used in the Bedrock Core Log Sheets,

which is enclosed in Appendix B.


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The freshly recovered rock cores were logged, photographed and subjected to Point Load Index Strength

testing. Rock core photographs are presented in Appendix E.

On every 1.5 m length of core, a number of point load index tests were performed to provide an indirectapproximation of the uniaxial compressive strength of the rock material.

Within a 9 m thick zone of the rock, within which the tunnel would most likely be located, packer tests were

carried out to estimate the bulk or secondary hydraulic conductivity (permeability) of the rock mass

surrounding the borehole. The tests were performed at 3 m intervals by the packer test method, using

double pneumatic seals. A double straddle pneumatic packer arrangement was used at the completion of

the coring of the individual boreholes. The tests were performed at three pressure increments which were in

excess of the external water pressure. In the test, the amount of water injected is measured with a flow

meter during regular time intervals. From these, the hydraulic conductivity (i.e. secondary permeability) of

the rock mass surrounding the test zone was calculated, using the following relationship:

k=[Q/2HL] [ln(L/r)]

where

k - is permeability;

Q - is the rate of water injection;

H - is the pressure head of water in the test section;

L - is the length of the test section;

r - is the radius of the test section.

Details and results of the tests are given in Table D5, Appendix D, which shows the depths below lake

bottom where the packers were set (i.e. test zone), the gauge pressures, and the calculated hydraulic

conductivity values. Hydraulic conductivity values are also shown on the borehole logs and are presented

graphically on the Profile Drawings Nos 6, 9 and 12.

Due to high gas pressures in the rock, packer tests were not performed in Borehole 207, and were

completed only partially in Borehole 301 before abandoning and grouting these boreholes.

After completing the coring and the in-situ tests, each borehole was fully grouted, under the supervision ofan MNR certified Examiner, to the surface of the bedrock using a cement grout. The quantity of the grout

premixed was about 15% more than the theoretical volume of the borehole. The depth to the top of the

grout from the level of the drilling platform was measured to confirm that it is approximately at rock surface.


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The reference datum for establishing water depths and sampling elevations was Lake Ontario Level. Lake

Ontario level was, during the duration of the investigation program, at Elevations 75.0+m, as determined

by the hourly records provided by Canadian Hydrographic Service, who monitor the lake level relative to the

International Great Lakes Datum (IGLD).

1.3.2 Laboratory Testing

The soil and bedrock samples were forwarded to Coffeys Markham laboratory, where samples of the

overburden soils and bedrock were selected for testing. The laboratory testing of the soil samples

consisted of measurement of natural water contents, grain size analyses (sieve and hydrometer analyses)

and Atterberg consistency limit tests. Test results are plotted on the borehole log sheets in Appendix B.

The grain size distribution curves and plasticity charts are presented on Figures C1 to C7 in Appendix C.

Testing of the rock cores, in addition to the point load index tests, consisted of hardness tests, uniaxial

compression (UCS) tests and the determination of Youngs elastic modulus and Poissons ratio. These

tests were performed by the Department of Mining Engineering of Queens University. The laboratory testdata on the rock cores is provided in Appendix C.

1.3.3 Geophysical Survey

Prior to Coffeys engagement on the project, CH2M commissioned ASI Group Limited of St. Catharines,

Ontario, to carry out a marine geophysical survey consisting of bathymetric, side scan sonar and

sub-bottom profiling survey. The results of these surveys were reported to CH2M in November 2009.

Because of the known presence of buried valleys in the bedrock, Coffey retained the ASI Group to perform

seismic profiling of the lake bottom in order to locate the extent and depths of any of these buried rock

valleys. The field work for this seismic survey was undertaken between June 4 and 10, 2010 covering two

proposed outfall alignments, each approximately 3 km in length. The results of this survey were reported toCoffey on July 14, 2010 and were used, in consultation with the members of the team (Durham and York

Regions, CH2M), to modify the original drilling program. A copy of the Geophysical Survey is attached as

Appendix G.

1.4 Summarized Stratigraphy

Both, the geotechnical and the geophysical survey established that throughout almost the entire length of

the proposed outfall alignment the surface of the bedrock is overlain by overburden soil deposits. The

thickness of these, at the borehole locations, range between 0 (BH301 and BH402) and 8.4 m, except at

the locations of the buried rock valleys, where overburden thicknesses of 14 m to 16 m were recorded. The

composition of the overburden soils is highly variable and ranges from very loose or soft organic silts or

clays to very dense glacial tills.

The surface of the bedrock was encountered between Elevations 58.6 m and 40.1 m and its quality was

explored by core drilling to between Elevations 21 m and 16 m, i.e. to a depth of 21 m to 39 m below rock

surface. To this depth, two rock formations were identified: The upper Whitby Shale and the lower and

older Lindsay Limestone Formation. The Upper Ordovician Whitby Formation has been subdivided into

Upper, Middle and Lower (Collingwood) members. The upper and middle members are greenish to

brownish grey fissile shale, while the lower Collingwood member is a dark brownish grey; often highly


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fossiliferous marl with black shale interbeds and is the most organic rich of the three members. While

pockets of gas can be found in all three members, they are more common in the Collingwood member. The

Lindsay Formation consists of grey; fine grained, fossiliferous limestone with thin shale interbeds It too

contains pockets of gas.

For details of the sub-lake bottom conditions encountered at the borehole locations, reference should be

made to the individual borehole log sheets and bedrock core log sheets presented in Appendix B.

1.5 Detailed Descr ipt ion of the Deposits

1.5.1 Overburden

The thickness of the soils (lake bottom sediments) that overlie the bedrock at the borehole locations ranged

from 0 to as much as 16.4 m. The thickest deposits (14.3 m to 16.4 m) were encountered in the areas of

the two buried valleys outside of which overburden thicknesses were typically varying from 4 m to 8 m. The

composition of these varied widely from fine grained clayey and organic soils to coarse grained sands andgravels and glacial tills. Similar wide variations were found in the consistency and compactness conditions

of the various deposits. Consistencies of very soft to hard and compactness conditions of very loose to

very dense were recorded. Not unexpectedly, the weakest and/or organic soils are found in the buried rock

valleys, where they extend to considerable depths below the lake bottom.

Details of the sub-lake bottom profiles are given on the borehole logs in Appendix B and the laboratory data

on these are presented in Appendix C on Figures C1 to C7. In the following paragraphs, the main

characteristics of the various soil types encountered in the boreholes will be briefly summarized.

1.5.1.1 Sandy Silt

Sandy silt, in very loose (N=0) condition was encountered in Boreholes 202 and 206. Grain size distribution

curves are given on Figure C1 in Appendix C showing 22-30% sand; 61-68% silt; and 8-15% clay size

particles.

1.5.1.2 Organic Silt

A 3.8 m to 4.4 m thick organic silt deposit was found in Boreholes 202 and 206. They are either very soft or

very loose as indicated by SPT N values of 0. A sample tested for particle sizes gave 14% sand; 72% silt

and 14% clay (see Figure C2). Atterberg consistency limit tests performed on the soil fines gave Liquid

Limit of 58% to 67%; Plastic Limit of 57% to 66% and Plasticity Indices of 1%.

1.5.1.3 Silt

Silt of low plasticity in very loose to dense condition was found in Boreholes 202 and 204 respectively. The

following consistency limits were obtained from two Atterberg tests: LL=14-21%; PL=11-18% and PI=3.


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1.5.1.4 Clayey Silt

The predominant soil type in Boreholes 203, 204 and 403 is a very stiff to hard clayey silt (CL-ML) deposit.

SPT N values ranged from 17 to greater than 50 blows for 76 mm penetration. Its consistency limits weremeasured to be LL=16-20%; PL=11-13% and PI=5-7%.

1.5.1.5 Silty Clay

A low plasticity (CL) silty clay deposit was found in Boreholes 202 and 206 in very soft (N=0) or very stiff

(N=29) consistency respectively. Its consistency limit properties were measured to be LL=29%; PL=19%

and PI=10%.

1.5.1.6 Sand

Relatively thin (0.8 to 2.4 m) sand layers were found in Boreholes 202, 203 and 206. The sand was in

compact (N=19) to very dense (N= 51) condition in Boreholes 202 and 203, but very loose (N=3-4) inBoreholes 206. Grain size analyses indicate 1-31% gravel; 49-83% sand; 10-16% silt; and 0-4% clay size

particles in the deposit (Figure C3).

1.5.1.7 Sand and Silt Till

Compact to very dense (N=17-94) glacial till was encountered in Boreholes 203, 204 and 205. The texture

of the till is sandy and silty as confirmed by grain size analyses, which gave 11-15% gravel, 38-52% sand;

26-34% silt and 7-14% clay. Where the percentage of clay is higher, the till has occasionally clayey silt

texture. Grading curves are shown on Figure C4.

1.5.1.8 Sand and Gravel

Present as a 1.0 m to 1.5 m thick layer, sand and gravel was found in Boreholes 205 and 206. Analysis of

a sample showed 34% gravel; 36% sand; 20% silt and 10% clay. Based on the in-situ penetration tests

which gave SPT N values of 10 blows/0.3 m to 79 blows/0.3 m, the deposit is in a compact to very dense

state of compaction.

1.5.2 Bedrock (General)

Bedrock formations of Upper and Middle Ordovician age underlie the Site, and are referred to as the Whitby

and Lindsay Formations. Bedrock surface elevations at the borehole locations range between 58.6 m and

40.1 m. These represent the surface of the Whitby Shale Formation which, at the borehole locations, is

about 7 to greater than 34 m thick. The surface of the underlying Lindsay Limestone Formation was

contacted between Elevations 43.9 m and 25.3 m, with the exception of Boreholes 402 and 403 which wereterminated in the Whitby formation, at Elevations 19.5 m and 19.3 m, respectively. It should be noted that

available geological maps indicate the presence of buried valleys in the bedrock marking probably the

locations of ancient glacial river channels. Two of these were detected and confirmed on the proposed

alignments by the geophysical seismic survey and are shown on Figures 6 and 7 of the Geophysical Report

in Appendix G. The locations of these valleys on land are shown on Drawing 2 in Appendix A.


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Rocks belonging to the Whitby Formation are typically weak to medium strong, brownish grey to black, fine

to very fine grained, brittle and moderately fissile and are thinly bedded. They consist of approximately

70% to 90% shale interbedded with limestone and are frequently bituminous and contain organic gases.[7]

The grey limestone of the Lindsay Formation is typically fine grained, fossiliferous and massively bedded

with thin shale interbeds. Two major joint sets located perpendicularly to each other are known to exist in

this formation. Joint spacing in one of them is close, less than 1 m and is wider, 1 m to 5 m, in the other[9]

.

The Lindsey Formation also contains pockets of gas.

The descriptive terms used on the record of rock cores and throughout the report are explained on the

Explanation of Terms Used in the Bedrock Core Log sheet in Appendix B preceding the log sheets. In

general, the conventions of the International Society of Rock Mechanics (ISRM) are adopted herein. The

measured index properties of the two formations are summarized in the sections that follow.

1.5.2.1 Whitby Formation

Total Core Recovery (TCR)

The total core recovery indicates the total length of rock core recovered expressed as a percentage of the

actual length of the core run (usually 1.5 m). The total core recovery was generally good, with values

ranging from 44% to 100%. In the individual boreholes the average TCR values ranged from 93% to 100%.

Solid Core Recovery (SCR)

Solid core recovery is the total length of solid, full diameter, rock core that was recovered and expressed as

a percentage of the length of the core run. Solid core recovery ranged from 0% to 100%, with average

values between 21% and 94%. The low values were recorded near the rock surface due to some

weathering in the surface zone, but almost throughout the full depth of the Formation in Borehole 302.

Rock Quality Designation (RQD)

The RQD value is obtained by measuring the total length of recovered rock core pieces which are longer

than 100 mm and expressing the sum total as a percentage of the length of the run. On the basis of the

recorded RQD values, which range between 0% and 100%, the rock quality is estimated to be very poor to

excellent. Average values of 8% to 78% recorded in the individual boreholes indicate a rock of very poor to

good quality. Again the lowest values were recorded in Borehole 302. Graphical presentations of the RQD

values are given in Appendix A on Drawings 4, 7 and 10.

The RQD values are a general indicator of the rock mass quality, however, in horizontally laminated, fissile

sedimentary rock formations (such as the Whitby), the reader is cautioned that RQD values are likely

conservatively low since the development of this index was primarily for igneous and metamorphic rocks.

RQD has strong directional bias. In our experience, the RQD index tends to underestimate the rock

quality in shale formations.


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A relationship between rock quality and RQD indices was suggested by Deere (1969) and is given below:

RQD (%) Designation of Rock Quality

0 - 25 Very Poor25 - 50 Poor50 -75 Fair75 - 90 Good90 -100 Excellent

Fracture Index (FI)

Frequency of fractures, or fracture index, is a measure of the frequency of fracturing and bedding plane

separations. It is expressed as the number of fractures per 0.3 m length of rock core run. Breaks which

were obviously induced by the drilling are excluded. A continuous vertical fracture, regardless of its length,

is counted as one fracture.

The recorded values ranged between 0 and over 25. Average values within the boreholes ranged from 1.5

to 5.6 and was 16.3 in Borehole 302. Planes of weaknesses along which the cores tended to break were

planes of bedding, the contact surfaces between shale and hard layers. Occurrence of sub-vertical

fractures was irregular and typically within hard layers. Their surface is usually planar, rough and dipping at

an angle close to 90 to the axis of the core.

Hard Layers

When recovering the core samples, the thickness of the interbedded hard limestone layers were

measured and their aggregate expressed as a percentage of the length of the core run. Hard layers are

defined herein as distinct stronger rock layers or lenses which have unconfined compressive strengthswhich exceed that of the bulk of the rock mass. This, however, is a subjective index based on visual

examination and relatively crude index strength tests. The measured thicknesses of individual hard layers

ranged from less than 25 mm to approximately 125 mm. Percentage of hard layers ranged from 0% to

100%, averaging at 0% to 21%. The observed percentage values are shown on the individual borehole log

sheets in Appendix B.

Weathering

In general, weathering of the Whitby Formation was estimated as slight to fresh, but generally fresh with

occasional weathering on discontinuity surfaces. A few layers of moderately weathered rock core were

recovered near the rock surface; thicknesses and occurrence of these zones were limited.

Point Load Index Strength

Indirect approximations of the compressive strength of the Whitby Formation were obtained by performing

point load tests on selected core samples. Tests were performed both in axial and diametric directions and

included tests on the weaker shale and the stronger calcareous siltstone and limestone layers. It was

observed that testing of shale samples in diametric direction typically resulted in irregular breaks along sub

horizontal planes due to the fissile nature of shale as would be expected. For more representative UCS

values, reference should be made to the laboratory uniaxial compressive tests, Table D4, Appendix D.


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Inferred unconfined compressive strength values were calculated as UCS=Is50 x 24 where Is50 represents

Point Load Index. Point load index strength tests performed on the weaker shale layers in the axial

direction gave inferred unconfined compressive strength values between 5 MPa and 88 MPa, with an

average at around 28 MPa. In the diametric direction, the inferred UCS values ranged between 1 MPa and

50 MPa, and an average value of 13 MPa was obtained for the shale samples. Testing of the stronger

limestone and calcareous siltstone layers produced higher UCS values. Inferred UCS values in axial

direction ranged from 70 MPa to 126 MPa, with average at around 106 MPa. Inferred UCS values in the

diametric direction ranged between 38 MPa and 94 MPa, averaging at around 63 MPa.

Test results are presented in the individual borehole log sheets and on Table 2, Appendix C.

Uniaxial Compressive Strength

Test results of the unconfined compressive strength of rock cores measured in the laboratory of Queens

University on thirteen (13) samples are presented in Table D4, Appendix D, and are also shown on the rock

core log sheets in Appendix B.

UCS test results of the thirteen (13) samples ranged from 7.4 MPa to 56.0 MPa with average at 28.3 MPa.

Based on these results, the shale is classified as a weak to strong, but generally medium strong rock

according to ISRM convention.

Density

The density of intact rock was measured on thirteen (13) samples and ranged from 2,490 kg/m3

to

2,710 kg/m3

with an average value of 2,600 kg/m3. (See Table D4, Appendix D)

Youngs Modulus (E)

The elastic or Youngs Modulus of the intact rock material was measured when performing the uniaxial

compression tests. Measured modulus values ranged between 0.6 GPa and 12.5 GPa, with an average

value of 5.4 GPa. Test results are presented in Table D4, Appendix D.

Poissons Ratio ()

The ratio of lateral to longitudinal strain in the elastic range of the intact rock was determined during the

uniaxial compression tests. Poissons ratio values ranged from 0.12 to 0.35, as shown in Table D4,

Appendix D.

Hardness

The hardness of the rock was determined using the Mohs Hardness Test method. Samples of both the

shale and hard limestone layers were tested by the Department of Mining and Geology, Queens

University, to obtain relative hardness parameters based on the Mohs Hardness Scale which is as follows:

Diamond 10Corundum 9Topaz 8Quartz 7

Apatite 5Fluorite 4


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Calcite 3Gypsum 2Talc 1

The scale is not of equal value as the difference in hardness between 9 and 10 is much greater than

between 1 and 2. According to the test results, hardness ranged from 1.5 to 5. Test results are presented

in Table D4, Appendix D.

Hydraulic Conductivity

Packer pressure tests, to estimate the hydraulic conductivity of the rock mass, were performed in the

Whitby Formation in Boreholes 205, 206, 206A, 302, 402 and 403. Tests in the Whitby Formation could not

be performed in Boreholes 207 and 301 due to the presence of gas under high pressure and duration. Test

results, given on the individual borehole logs, are summarized in Table D5 in Appendix D and are also

presented graphically on Drawings 6, 9 and 12 in Appendix A.

The highest hydraulic conductivity value inferred from the tests was 4 x 10-3

cm/s recorded about 3 m

above the tunnelling zone in Borehole 206. Elsewhere, measured values ranged from 10-4

cm/s to 10-6

cm/s or were less than 10-6

cm/s as indicated by no water takes during the pressure packer tests.

In-situ Stresses

In-situ stress measurements were not performed as part of this investigation. In-situ stress measurements,

however, were made in the Whitby Formation in connection with the design and construction of the

Darlington Power Generating Station located about 22 km to the east[9]

. The values there obtained are

believed to be applicable to this site as well. These measurements gave major principal stress values of

9 MPa to 11 MPa and minor principal stress values of 4 MPa to 6 MPa.

GasThe Whitby Formation is known to contain pockets of combustible gas.

[7]

During the present investigation the presence of gas was observed on a number of occasions. The

locations where gas was observed, along with the associated gas monitor readings, are given in Table D7

in Appendix D.

1.5.2.2 Lindsay Formation

Total Core Recovery (TCR)

The total core recovery indicates the total length of rock core recovered expressed as a percentage of the

actual length of the core run (usually 1.5 m). The total core recovery in the Lindsay Formation wasgenerally excellent, with values ranging from 94% to 100%. In the individual boreholes, the average values

were 99% to 100%.


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Solid Core Recovery (SCR)

Solid core recovery is the total length of solid, full diameter rock core that was recovered and expressed as

a percentage of the length of the core run. Solid core recovery ranged from 88% to 100%, with averagevalues between 96% and 100%. Exception to this was only Borehole 302, where lower values of 27% to

83% and average 64% were recorded.

Rock Quality Designation (RQD)

The RQD value is obtained by measuring the total length of recovered rock core pieces which are longer

than 100 mm and expressing the sum total as a percentage of the length of the run. On the basis of the

recorded RQD values, which range between 58% and 100%, the rock quality is estimated to be fair to

excellent. Average values of 84% to 100% recorded in the individual boreholes indicate a rock of good to

excellent quality. Lower (7% to 47%) values were recorded in Borehole 302, where an average RQD value

of 25% indicate very poor to poor quality rock. RQD values are given on the individual borehole logs and

also graphically on the Profile Drawings Nos 4, 7 and 10 in Appendix A.

A relationship between rock quality and RQD indices was suggested by Deere (1969) and is given below:

RQD (%) Designation of Rock Quality

0 25 Very Poor25 50 Poor50 -75 Fair75 90 Good90 -100 Excellent

Fracture Index (FI)Frequency of fractures, or fracture index, is a measure of the frequency of fracturing and bedding plane

separations. It is expressed as the number of fractures per 0.3 m length of rock core run. Breaks which

were obviously induced by the drilling are excluded. A continuous vertical fracture, regardless of its length,

is counted as one fracture.

The recorded FI values ranged between 0 and 6 and average values within the boreholes were generally


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13

Point Load Index Strength

Indirect approximations of the compressive strength of the Lindsay Formation were obtained by performing

point load tests on selected core samples. Tests were performed both in axial and diametric directions onthe limestone layers. Inferred unconfined compressive strength values were calculated as UCS=Is50 x 24

where Is50 represents Point Load Index. Inferred unconfined compressive strength values range between 8

MPa and 255 MPa, with an overall average value of 131 MPa. In contrast with the Whitby shale Formation

there was noticeably less difference between the tests results performed in the axial or diametral direction.

Average inferred UCS values measured in the axial direction ranged from 64 MPa to 116 MPa and between

54 MPa and 86 MPa when the test was performed in the diametral direction. Based on these average

values the rock is classified as being strong to very strong, but generally strong. Test results are presented

on the individual borehole log sheets and in Table D3, Appendix D.

For more representative UCS values, reference should be made to results of the uniaxial laboratory tests

which can be found in Table D4, Appendix D.

Uniaxial Compressive StrengthTest results of the unconfined compressive strength of rock cores measured in the laboratory of Queens

University on twenty one (21) samples are presented in Table D4, Appendix D and are also shown on the

rock core log sheets in Appendix B.

UCS values of the core samples ranged from 24.4 MPa to 70.3 MPa with average at 47.4 MPa. Based on

these results the rock formation is classified as a weak to strong, but generally a medium strong rock

according to ISRM convention.

Density

The density of intact rock, measured on twenty one (21) samples, ranged from 2,640 kg/m

3

to 2,690 kg/m

3

with average value of 2,670 kg/m

3.

Youngs Modulus (E)

The elastic or Youngs Modulus of the intact rock material was measured when performing the uniaxial

compression tests. Measured modulus values ranged between 6.0 GPa and 19.4 GPa, with an average

value of 13.6 GPa. Test results are presented in Table D4, Appendix D.

Poissons Ratio ()

The ratio of lateral to longitudinal strain in the elastic range of the intact rock was determined by the uniaxial

compression tests. The Poissons ratio values ranged from 0.10 to 0.31 as shown in Table D4,

Appendix D.


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Hardness

The hardness of the rock was determined using the MOHs Hardness Test procedure. Samples of both the

shale and hard limestone layers were tested by the Department of Mining and Geology, QueensUniversity, to obtain relative hardness parameters based on the MOHs Hardness Scale which is as follows:

Diamond 10

Corundum 9

Topaz 8

Quartz 7

Apatite 5

Fluorite 4

Calcite 3

Gypsum 2

Talc 1

The scale is not of equal value as the difference in hardness between 9 and 10 is much greater than

between 1 and 2. According to the test results, hardness ranged from 2.5 to 5 with an average value of 4.0.

Test results are presented in Table D4, Appendix D.

Hydraulic Conductivity

Since the anticipated zone of tunneling is in the Lindsay Formation hydraulic conductivity tests were

performed in every borehole where this formation was encountered, except in Borehole 207 where down

hole gas pressure prevented testing. Test results, given on the individual borehole logs, are summarized inTable D5 in Appendix D and are also presented in Drawing 6 in Appendix A.

The highest hydraulic conductivity value, inferred from the test results, was 3x10-5

cm/s at the boundary of

the two rock formations. Elsewhere, the values were typically 10-6

cm/s or less as indicated by no water

takes during the pressure packer tests.

In-situ Stresses

In-situ stress measurements were not performed as part of this investigation. In-situ stress measurements

however were made in the Lindsay Formation in connection with the design and construction of the

Darlington Power Generating Station (PGS) located only about 22 km to the east[9]

. The values obtained at

the PGS site are believed to be applicable to this site as well. At the Darlington Station, the measured

major principal stress values ranged from 10 MPa to 14 MPa and minor principal stress values werebetween 6 MPa to 9 MPa. The orientation of the major principal stress is N70

oE.

[9]


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15

Time-Dependent Deformation Characteristics (TDD)

The Lindsay Formation, similarly to the other Paleozoic sedimentary rock formations found in Southern

Ontario, is known to exhibit long term, time dependent deformation characteristics (TDD) also referred to asrock swelling or rock squeezing. An approximate indication of the swelling potential of the rock can be

obtained in the laboratory from free swell tests. Tests performed on the Lindsay Formation in connection

with the Darlington PGS indicated a horizontal swelling potential, defined as the expansion strain per log

cycle of time, varying from negligible to 0.1% but typically 0.05%.[9]

This range was believed to be due to

natural variations in the rock formation. The low values were associated with core samples consisting

predominantly of limestone with no shale, while the higher values were obtained on samples containing

larger amounts of shale interbeds. Field measurements of the horizontal rock convergence during

construction confirmed a maximum value of 0.037% of tunnel diameter per log cycle of time.

GasThe Lindsay Formation is known to contain occasional pockets of combustible gas. During theinvestigation, small pockets of gas were recorded in Boreholes 202, 204, 205, 206A, 207, 301 and 302. On

these occasions the gas dissipated within 20 minutes to 60 minutes except in Boreholes 206A, 207 and

301, where larger gas pockets were recorded and where the gas was burned for about seven (7) hours or

dissipated overnight. In Boreholes 207 and 301 gas was not recorded during drilling, but was encountered

during the in-situ hydraulic conductivity (packer) testing. In both cases, the presence of the gas prevented

successful completion of the packer tests.

The locations where gas was observed, along with the associated gas monitor readings, are given in

Table D7 in Appendix D.

1.6 Environmental and Chemical Soil and Bedrock Quality Testing

1.6.1 Environmental Testing

Eleven (11) soil samples, including six (6) samples representative of native soil and five (5) rock samples

were selected from the boreholes for environmental testing to assess on-site management and off-site

disposal options for the excavated soil and rock. The samples were selected for representative coverage of

the site and layers to be excavated. Hydrocarbon odour in Borehole 203 at the depth between 32.1 m and

33.6 m (shale - Whitby formation) and Borehole 205 at the depth between 24.5 m and 26.4 m (shale -

Whitby formation), and occasional partially decayed wood fragments (tree branches) encountered in

Borehole 202 at the depth below 14 m and Borehole 206 at the depth between 22.5 m and 36 m were

observed during the samples collection. The samples were analyzed by AGAT Laboratories in

Mississauga, Ontario, which is a certified laboratory according to the Standards Council of Canada (SCC)

and the Canadian Association for Laboratory Accreditation Inc., (CALA). The laboratory indicated to Coffey

that they followed MOE QA/QC procedures. The soil and rock samples were analyzed for general

chemistry and inorganic parameters including pH, heavy metals, sodium adsorption ratio (SAR), and

electrical conductivity (EC) as set out in the Ministry of Environment (MOE) document Soil, Ground Water

and Sediment Standards for Use Under Part XV.1 of the Environmental Protection Act (O. Reg. 153/04 as

amended), dated April 15, 2011, (known as MOE Standards), and leachate analyses using the toxicity

characteristic leaching procedure (TCLP) required by O.Reg. 347 (amended to O. Reg. 558/00, Leachate


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16

Quality Criteria) for waste classification purposes. The laboratory results were compared with Table 2 Full

Depth Generic Site Condition Standards in a Potable Ground Water Conditions, Residential / Parkland /

Institutional (RPI) and Industrial / Commercial / Community (ICC) Property Use and Schedule 4 Leachate

quality criteria listed in O.Reg. 347.

Although chemical analysis under O.Reg. 153/04 (as amended) is only applicable to soil; it is assumed that

the rock material may be considered as fill once weathered to soil consistency. As such, the purpose of the

analysis of the rock samples was to assess its environmental quality as a soil that would eventually be

produced from the weathering of the rock. The submitted rock samples were pulverized in the laboratory

prior to analysis.

Five (5) soil samples were also tested for their aggressiveness on concrete and five (5) rock samples were

analysed for the aggressiveness of the rock on concrete. These samples were analyzed for sulphate

(SO4).

A summary of the samples tested and the types of tests performed are listed in Table 1.6.1.

Table 1.6.1: Summary of Environmental and Chemical Tests

BH No.Sample No. Depth (m) Soil/Rock Type

O. Reg.

153(511)

Table 2 Metals

and Inorganics

O. Reg.

347(558)

Metals and

Inorganics

SO4

202 SS2,3 17.5-18.75 Clayey silt

202 R16 52.15 Limestone/

siltstone

202 R17 52.2 Limestone/

siltstone

203 SS3 17.2-17.68 Silty clay

203 SS5 18.7-19.2 Gravelly sand

203 R19 48.77 Silty limestone

to siltstone


to siltstone

204 SS2 17.1-17.6 Clayey silt

204 SS4 18.72-19.13

Clayey silt

204 SS5 19.4-19.89 Sandy silt


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BH No.Sample No. Depth (m) Soil/Rock Type

O. Reg.

153(511)

Table 2 Metalsand Inorganics

O. Reg.

347(558)

Metals andInorganics

SO4


to siltstone


to siltstone


to siltstone

205 SS2 18.75-19.2 Sandy clayey

silt

205 SS5 21.03-21.49

Silty sand

205 R6 31.7 Shale

206 SS3 24.54-24.99

Silt

206 SS4 25.3-25.76 Silt

The laboratory results which are presented in Appendix F showed that EC and concentration of free

cyanide in the soil sample Borehole 202 SS2, 3 exceeded the new MOE Table 2 Standards for RPI

property use. Concentration of free cyanide in this sample also exceeded the new MOE Table 2 Standardsfor ICC property use. This sample represents the soil material between 17.5-18.75 m depth in this borehole.

Concentration of hot water extractable boron in the rock sample Borehole 205 R6 exceeded the new MOE

Table 2 Standards for RPI and ICC property use. This sample represents the rock material at 31.7 m depth

in this borehole.

SAR and/or EC in the rock samples Boreholes 202 R17, 203 R19, 204 R13, 204 R20 and 205 R6

exceeded the new MOE Table 2 Standards for RPI property use. EC in the rock sample Borehole 203 R19

exceeded the new MOE Table 2 Standards for ICC property use as well. The laboratory results for the rock

sample Borehole 204 R20 also showed that that the sample had a pH of 9.15. These samples represent

the material between 31.7 m and 52.2 m depth. The rock sample Borehole 203 R19 represents the material

at approximate depth of 48.77 m.

The Leachate concentrations of the metals and inorganics in all samples analysed were below the

Schedule 4 Leachate quality criteria listed in O.Reg. 347 (amended to O.Reg. 558/00). Therefore, the

tested soils can be classified as non-hazardous soil waste for the purpose of off-site disposal at a receiver

licensed to accept such waste.


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18

Based on the analytical laboratory results, the soil samples taken from the location at Boreholes 203 and

205 at the depth between 17.1 m and 19.2m, and at the location of Borehole 206 at the depth between

24.54 m and 24.99 m met the new MOE Table 2 Standard criteria for RPI property use. Therefore, if soil

from these areas and depths is to be excavated and disposed, this material is considered chemically

suitable for re-use at redevelopment sites accepting fill that meets the new MOE Table 2 RPI Standards,

provided that the soil is free of stains, odours, debris, cinders, mixed materials, etc. It should be noted that

acceptance of this material will be at the discretion of the receiving site(s).

The soil sample at the location of Borehole 202 at the depth between 17.5 and 18.75 exceeded the new

MOE Table 2 ICC Standards. Therefore, the soil material from the location between Boreholes 202 and

203 at the depth between 17.5 m and 18.75 m is not considered chemically suitable for re-use at the

redevelopment sites accepting fill that meets MOE Table 2 ICC Standards. If soil from this area is to be

excavated and disposed, additional analyses will be required to determine the limits of the free

cyanide-impacted soil. The extent and depth of the free cyanide-impacted soil were not determined in this

investigation. This material will require off-site disposal as a waste at a receiver licensed to accept suchwaste. It should be noted that acceptance of this material will be at the discretion of the receiving site(s).

The laboratory results for rock samples indicated that the samples at the locations of Borehole 202 at the

approximate depth of 52.2 m and Borehole 204 at the depth between 41.28 m and 51.97 m exceeded the

new MOE Table 2 RPI Standards due to the exceedance of EC and/or SAR, but met Table 2 Standards for

ICC property use. If material from this area is to be excavated and disposed, additional analyses will be

required to determine the limits of the EC and/or SAR-impacted material. The extent and depth of EC

and/or SAR-impacted rock were not determined in this investigation. Therefore, if the material from these

areas is to be excavated and disposed, weathered and used as soil, it is considered chemically suitable for

re-use at redevelopment sites accepting fill that meets the new MOE Table 2 ICC Standards. The pH of the

rock in the vicinity of Borehole 204 should be retested prior to the material being sent off-Site as fill for a

redevelopment site. It should be noted that acceptance of this material will be at the discretion of thereceiving site(s).

EC in the rock sample Borehole 203 R19 at approximate depth of 48.77 m and the concentration of hot

water extractable boron in the sample Borehole 205 R6 at approximate depth of 31.7 m exceeded the new

MOE Table 2 Standard for ICC property use. Therefore, the rock material from these locations is not

considered chemically suitable for re-use at the redevelopment sites accepting fill that meets MOE Table 2

ICC Standards. If the material from this area is to be excavated and disposed, additional analyses will be

required to determine the limits of the EC and hot water extractable boron-impacted rock. The extent and

depth of the EC and hot water extractable boron-impacted rock were not determined in this investigation.

This material will require off-site disposal as a waste at a receiver licensed to accept such waste. It should

be noted that acceptance of this material will be at the discretion of the receiving site(s).

The analytical test results are appended to this report in Appendix F.

Coffey makes no warranty, express or implied, as to whether or not excavated soils and shale will be

accepted by receivers. Off-site receivers will likely require additional testing prior to acceptance of any

soils. They may also reject soils based on other criteria, such as presence of organic material, peat,

topsoil, rubble, or elevated moisture content.


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19

The testing has been conducted in order to assess the possible options for off-site soil and shale disposal

only and is not intended to constitute a Phase 2 Environmental Site Assessment and as such does not

comment on the environmental condition of the Site. Soil and shale quality may vary at locations other than

those tested.

During excavation, soils or shale that exhibit stained, hydrocarbon, solvents or other odours, or contain

rubble, debris, cinders or other visual evidence of impact, must not be taken to a clean fill site. These

materials should be segregated on-Site and this office should be contacted immediately.

1.6.2 Chemical Testing

The sulphate (SO4) resistance of concrete in contact with the soils and rock was evaluated by performing

water-soluble sulphate tests on the five (5) soil and five (5) rock samples listed in Table 1.6.1 in Section

1.6.1. Compared with Table 3 specified in the Canadian Standard Association (CSA) specification CSA

A.23.1-09, the test results revealed that the sulphate concentration in the soil samples was between 220

and 1110 g/g or between 0.022% and 0.111%. In the rock samples, the SO4 concentration was between52.2 g/g and 146 g/g or between 0.00522% and 0.0146%.

Based on the results of the limited testing performed on the selected soil and rock samples, it appears that

the concentration of SO4 in the overburden soils has in places the potential of being aggressive on

concrete, and therefore, the use of high sulphate-resistant hydraulic cement (HS) is warranted. In contrast,

the SO4 concentration in the rock core samples tested indicates only a moderate degree of exposure (S-3)

and therefore, general use of hydraulic cement (GU) or high early strength hydraulic cement (HE) can be

used for the manufacturing of concrete in contact with the rock.

The analytical data are attached to this report inAppendix F.

1.7 Statement of Limi tations

The Statement of Limitation, as quoted in Appendix F, is an integral part of this report.

For and on behalf of Coffey Geotechnics Inc.

Ivan P. Lieszkowszky, P.Eng., FEIC Janos Garami, P.Eng., FECSenior Principal Senior Geotechnical Engineer


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LIST OF REFERENCES

[1] Franklin, J. A.: Rock Engineering, McGraw-Hill, 1989, p.41

[2] Morton, J.D., Lo, K.Y. and Belshaw, D.: Rock performance consideration for shallow tunnels inbedded shales with high lateral Stresses, Proceedings, 12

thCanadian Rock Mechanics

Symposium, Kingston, Ontario, 1975.

[3] Lo, K.Y. and Morton, J.D.: Tunnels in bedded rock with high horizontal stresses, CanadianGeotechnical Journal, Vol. 13, 1976.

[4] Lo, K.Y., Palmer, J.H.L. and Quigley, R.M.: Time-dependent deformation of shaley rocks in

southern Ontario, Canadian Geotechnical Journal, Vol. 15, 1978.

[5] Franklin, J.A. and Hungr, O.: Rock Stresses in Canada, their relevance in engineering projects,Rock Mechanics, by Springer-Verlag, 1978.

[6] Lo, K.Y., Cooke, B.H. and Dunbar, D.D.: Design of buried structures in squeezing rock in Toronto,Canada, Canadian Geotechnical Journal, Vol. 24, 1987.

[7] J.A. Franklin: Evaluation of Shales for Construction Purposes, MOT, 1983

[8] Lo, K.Y and Yuen, C.M.K. Design of tunnel lining in rock for long term time effects. Canadian

Geotechnical Journal, Volume 18, 1981

[9] Lo, K.Y. and Lukajic, Boro. Predicted and measured stresses and displacements around theDarlington Intake Tunnel. Canadian Geotechnical Journal, Vol. 21, 1984

[10] Groundwater Resources of the Duffin Creek Rouge River Drainage Basins. Ministry of the

Environment, Ontario, Water Resources Report 8.1977.

Documents

Geo Technical Investigation Volume 1