appendix b: geotechnical report

Appendix B:

Geotechnical Report

Geotechnical Factual Report August 2018Prosser’s Rock, St. John’s, Newfoundland FFC-NL-3129-001

Preface

Fisheries and Oceans Canada (DFO) retained Fracflow Consultants Inc. to undertake a marine

geotechnical site investigation at the Prosser’s Rock site in St. John’s, NL. This investigation

was generally conducted according to the stipulations outlined in the Standing Offer (No.

EA003-182945/001/PWD) between Public Works and Government Services Canada (PWGSC)

and Fracflow Consultants Inc. and under Purchase Order No. F6140-181024 from DFO.

The proposed scope of work for the Prosser’s Rock site project consisted of ten (10) dynamic

cone penetration test (DCPTs) holes from a barge and one (1) borehole from the edge of the

parking lot using an extended drilling platform. The field work for this investigation was

conducted between July 20 and August 1, 2018, and the revised scope of work due to high

winds, large wake impacts from vessel movement through the narrows and poor sea conditions

consisted of five (5) DCPTs and data from fourteen (14) boreholes that were drilled on this site

as part of earlier investigations. The presence of shipping containers on the parking lot area

prevented access to the proposed land based borehole location and a review of the geotechnical

data from three (3) boreholes that were drilled in 2016 close to this proposed borehole location

concluded that these boreholes provided sufficient data in the area in which the land based

borehole was planned. Environmental samples were collected using a grab sampler where

ground conditions permitted. The subsurface soil conditions have been inferred from the DCPT

blow counts that were recorded during the field program. The depths for refusal of the DCPTs

ranged from -12.8 m LNT to -17.6 m LNT. Refusal was not achieved for two (2) DCPTs whose

depth ranged from -19.7 m LNT to -29.2 m LNT. The bedrock description is based on the

bedrock outcrops in the adjacent road cut and the observation of the strike and dip

(approximately 60 to 65 degrees to the southeast) of the bedrock as exposed in hillside exposures

on both sides of the Harbour. The steep dip of the bedrock produces highly variable depths to the

bedrock surface both along strike and perpendicular to strike.

Fracflow Consultants Inc., File 3129 i


TABLE OF CONTENTS

Preface.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i

List of Tables. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii

List of Appendices. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii

1.0 INTRODUCTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

2.0 SITE DESCRIPTION AND GENERAL GEOLOGY. . . . . . . . . . . . . . . . . . . . . . . . . . 2-1

3.0 INVESTIGATIVE PROCEDURES.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1

4.0 SUBSURFACE CONDITIONS AND CHARACTERIZATION. . . . . . . . . . . . . . . . . 4-1

4.1 Soil Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1

4.2 Bedrock Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1

5.0 REFERENCES.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1

Fracflow Consultants Inc., File 3129 ii


List of Tables

Table 1.1 Summary of DCPT Geotechnical Investigations at Prosser’s Rock, St. John’s, NL.

Table 1.2 Summary of Sampling Depths for the Marine Sediment Samples.

List of Appendices

Appendix A Borehole and DCPT Location Map

Appendix B DCPT Logs

Appendix C 2016 Prosser’s Rock Geotechnical Investigation

Fracflow Consultants Inc., File 3129 iii


1.0 INTRODUCTION

Fisheries and Oceans Canada (DFO) retained Fracflow Consultants Inc. to undertake a marine

geotechnical site investigation at the Prosser’s Rock site in St. John’s, NL. This investigation

was generally conducted according to the stipulations outlined in the Standing Offer (No.

EA003-182945/001/PWD) between Public Works and Government Services Canada (PWGSC)

and Fracflow Consultants Inc. and under Purchase Order No. F6140-181024 from DFO.

The proposed scope of work for the Prosser’s Rock site project consisted of ten (10) dynamic

cone penetration test (DCPTs) holes from a barge and one (1) borehole from the edge of the

parking lot using an extended drilling platform. The field work for this investigation was

conducted between July 20 and August 1, 2018, and the revised scope of work due to high

winds, large wake impacts from vessel movement through the narrows and poor sea conditions

consisted of five (5) DCPTs and data from fourteen (14) boreholes that were drilled on this site

as part of earlier investigations. The presence of shipping containers on the parking lot area

prevented access to the proposed land based borehole location and a review of the geotechnical

data from three (3) boreholes that were drilled in 2016 close to this proposed borehole location

concluded that these boreholes provided sufficient data in the area in which the land based

borehole was planned. Environmental samples were collected using a grab sampler where

ground conditions permitted. The subsurface soil conditions have been inferred from the DCPT

blow counts that were recorded during the field program. The depths for refusal of the DCPTs

ranged from -12.8 m LNT to -17.6 m LNT. Refusal was not achieved for two (2) DCPTs whose

depth ranged from -19.7 m LNT to -29.2 m LNT. The bedrock description is based on the

bedrock outcrops in the adjacent road cut and the observation of the strike and dip of the bedrock

as exposed in hillside exposures on both sides of the Harbour. The steep dip (approximately 60

to 65 degrees) of the bedrock produces highly variable depths to the bedrock surface both along

strike and perpendicular to strike. A summary of the field work that was conducted is provided

in Table 1.1 and Table 1.2.

Fracflow Consultants Inc., File 3129 1-1


This report contains a factual presentation and full disclosure of all findings of the subsurface

investigation. The following sections provide: (1) a description of the site and the general

geology of the area; (2) a summary of the investigative procedures used; and (3) the inferred

bearing capacity of the soil conditions. Appended to this report is a site plan showing the

borehole locations and the detailed geotechnical logs for each DCPT.

Table 1.1 Summary of Dynamic Cone Penetration Test, Prosser’s Rock, St. John’s, NL.

DCPT #DCPT depth

below seabed (m)Water Depth

below LNT (m)Total depth

below LNT (m)Comments

PC2 -5.56 -7.24 -12.8 Refusal at -12.80 m LNT

PC3 -3.51 -14.16 -17.67 Refusal at -17.67 m LNT

PC6 -13.73 -15.46 -29.19 Refusal not achieved

PC7 -7.17 -12.53 -19.7 Refusal not achieved

PC9 -2.94 -14.21 -17.15 Refusal at - 17.15 m LNT

Table 1.2 Summary of Sampling Depths for the Marine Sediment Samples.

Sample ID Sampling Date Sample TypeSampling Depth

(m below sea bed)

3129-PC3-MS1-0Z August 10, 2018 Soil Harbour bottom

3129-PC9-MS1-0Z August 10, 2018 Soil Harbour bottom



2.0 SITE DESCRIPTION AND GENERAL GEOLOGY

Prosser’s Rock is located on the south side of St. John’s Harbour adjacent to the Fort Amherest

Small Boat Basin. This basin sits at the mouth of St. John’s Harbour. Overburden in the area is

characterised by till veneer and moraine of varying thickness overlying bedrock (Water

Resources Division, 1984). Bedrock in the area consists of sedimentary rocks with steep exposed

rock face and rapid elevation changes. This bedrock is a park of the Signal Hill Group formed by

red, gray, and green sandstone, conglomerate and shale (Water Resources Division, 1984).



3.0 INVESTIGATIVE PROCEDURES

At the Prosser’s Rock site, DCPTs were driven from a barge at five (5) locations, and

environmental samples were collected at two (2) of these locations. The borehole, DCPT and

environmental sample locations are shown on the site plan in Appendix A.

Previously geotechnical investigations at this location were conducted in two different periods.

The first geotechnical investigation (Fracflow 2007) was conducted between November 21, 2006

and March 3, 2007 and included drilling five (5) boreholes from a barge and attempting two (2)

other boreholes at the approximate locations requested by PWGSC with split-spoon sampling

and Standard Penetration Tests (SPTs) using an NW/NQ diamond drill string. In addition, during

this 2007 investigation, a total of five (5) boreholes were drilled to bedrock from land. The

second geotechnical investigation (Fracflow 2016) consisted of three (3) boreholes that were

drilled at three (3) locations in 2016 using a Mobile B-47 drill rig on a barge.

The 2016 report containing detailed information of the completed boreholes can be found in

Appendix C. The 2007 report can be obtained from Fracflow or from Public Works and

Government Services Canada files.

The five (5) Dynamic Cone Penetration Tests (DCPTs) that were completed during this current

investigation consisted of driving the pen cone into the ground using a 63.5 kg weight falling a

distance of 760 mm and the number of blow counts recorded for each 150 mm the cone

advanced. The cone was driven into the soil until practical refusal occurred (50 blows per

150 mm or equivalent) at three (3) locations but had to be terminated at the other two (2)

locations due to high boat wakes and strong wind conditions before reaching refusal.



4.0 SUBSURFACE CONDITIONS AND CHARACTERIZATION

Subsurface characterization is based on the field data collected from the five (5) Dynamic Cone

Penetration Tests. Detailed logs of the geological conditions at each location are provided in

Appendix B.

4.1 Soil Description

Overburden in the area is characterized by till veneer and moraine of varying thickness overlying

bedrock (Water Resources Division, 1984). The overburden on the harbour bottom, based on the

DCPT blow counts, is a very soft sediment that did not support the weight of the DCPT rods

until the DCPT was within a few metres of the bedrock surface. The overburden layer below the

very soft upper sediment layer is inferred to be fine to medium sand, based on the recorded blow

counts.

4.2 Bedrock Description

Bedrock in the area consists of sandstones, siltstones, mudstones, and conglomerates of the

Signal Hill Formation (King, 1990). The bedrock at this location consists primarily of quartz rich

sandstone with a compressive strength that exceeds 200 MPa.



5.0 REFERENCES

Canadian Geotechnical Society (CGS), 1992. Canadian Foundation Engineering Manual, 3rd

Edition, Technical Committee on Foundations, 512 p.

Fracflow, 2016. Geotechnical Factual Report, Prosser’s Rock Small Boat Basin, St. John’s

Harbour, NL, Department of Fisheries and Oceans, March 2016.

Fracflow, 2007. Geotechnical Factual Report, Prossor’s Rock, St. John’s Newfoundland and

Labrador, Public Works and Government Services Canada, March 2007.

King, A.F., 1990. Geology of the St. John’s area, parts of NTS sheets 1N/7E, 1N/7F, 1N/7G,

1N/10B, A, 1N/10C, 1N/10D, 1N/10F, and 1N/10G, Map 90-120, Report 90-02,

Newfoundland and Labrador Department of Mines and Energy, Geological Survey

Branch.

Water Resources Division, 1984. Hydrogeology of the Avalon Peninsula Area, Water Resources

Report 2-6, Water Resources Division, Newfoundland Department of Environment.


APPENDIX A

Borehole and DCPT Location Map

APPENDIX B

DCPT Logs

PC2Marine Geotechnical Investigation

Fisheries and Oceans Canada

St. John's, NL

3129

August 1 , 2018

0 m LNT

Harbour bottom (-7.24 m LNT)

Pencone sank 1.37 m into soft sediments underown weight

0

-7.24

-8.6142411

2.50.524

0.5

20 40 60 80

Dynamic Cone Penetration Test

Formation Drilling Ltd.

Geodetic

Log of DCPT:Project:

Client:

Location:

Project No:

Date:

Fracflow Consultants Inc.

154 Major's Path

St. John's, NL A1A 5A1

Phone: (709) 739-7270

Fax: (709) 753-5101

Drilling Method:

Driller:

Datum:

Sheet: 1 of 2

De

pth

0 0ft m

1

1

2

2

3

3

4

4

5

5

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32

33

Geologic Description

Ele

va

tio

n (

m)

Blo

ws p

er

15

0 m

m

Standard Penetration Test"N" Value per 300 mm



St. John's, NL

3129

August 1 , 2018

DCPT:4 / 2 / 4 / 1

/ 1 / 2.5 / 0.5 / 2 / 4 / 0.5 / 0.5 / 4

/ 5 / 2 / 5 / 6 / 4 / 6 / 4 / 4 / 5 / 5 / 5 / 7

/ 4 / 5 / 13 / 51 for 0.0 m (Refusal)

End of Borehole

-12.8

0.50.5

4525646445557451351

20 40 60 80



Geodetic


Client:

Location:

Project No:

Date:


154 Major's Path


Phone: (709) 739-7270

Fax: (709) 753-5101

Drilling Method:

Driller:

Datum:

Sheet: 2 of 2

De

pth

33

11

34

12

35

13

36

14

37

15

38

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Ele

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tio

n (

m)

Blo

ws p

er

15

0 m

m




St. John's, NL

3129

August 1, 2018

0 m LNT 0

20 40 60 80



Geodetic


Client:

Location:

Project No:

Date:


154 Major's Path


Phone: (709) 739-7270

Fax: (709) 753-5101

Drilling Method:

Driller:

Datum:

Sheet: 1 of 2

De

pth

0 0ft m

1

1

2

2

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3

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Ele

va

tio

n (

m)

Blo

ws p

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15

0 m

m


St. John's Harbour



St. John's, NL

3129

August 1, 2018



DCPT:5 / 9 / 20 / 20

/ 51 for 0.06 m (Refusal)

End of Borehole

-14.2

-16.9

-17.6

59202051

20 40 60 80



Geodetic


Client:

Location:

Project No:

Date:


154 Major's Path


Phone: (709) 739-7270

Fax: (709) 753-5101

Drilling Method:

Driller:

Datum:

Sheet: 2 of 2

De

pth

33

11

34

12

35

13

36

14

37

15

38

16

39

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18

41

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Ele

va

tio

n (

m)

Blo

ws p

er

15

0 m

m




St. John's, NL

3129

July 21, 2018

0 m LNT 0

20 40 60 80



Geodetic


Client:

Location:

Project No:

Date:


154 Major's Path


Phone: (709) 739-7270

Fax: (709) 753-5101

Drilling Method:

Driller:

Datum:

Sheet: 1 of 3

De

pth

0 0ft m

1

1

2

2

3

3

4

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Ele

va

tio

n (

m)

Blo

ws p

er

15

0 m

m


St. John's Harbour



St. John's, NL

3129

July 21, 2018



-15.5

-19.51

20 40 60 80



Geodetic


Client:

Location:

Project No:

Date:


154 Major's Path


Phone: (709) 739-7270

Fax: (709) 753-5101

Drilling Method:

Driller:

Datum:

Sheet: 2 of 3

De

pth

33

11

34

12

35

13

36

14

37

15

38

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Ele

va

tio

n (

m)

Blo

ws p

er

15

0 m

m




St. John's, NL

3129

July 21, 2018

DCPT:1 for 0.15 m / 1 for 0.72 m

/ Sank 8.80 m under own weight

End of Borehole

-29.2

1

0

0

0

0

0

0

20 40 60 80



Geodetic


Client:

Location:

Project No:

Date:


154 Major's Path


Phone: (709) 739-7270

Fax: (709) 753-5101

Drilling Method:

Driller:

Datum:

Sheet: 3 of 3

De

pth

66

21

67

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Ele

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n (

m)

Blo

ws p

er

15

0 m

m




St. John's, NL

3129

July 21, 2018

0 m LNT 0

20 40 60 80



Geodetic


Client:

Location:

Project No:

Date:


154 Major's Path


Phone: (709) 739-7270

Fax: (709) 753-5101

Drilling Method:

Driller:

Datum:

Sheet: 1 of 2

De

pth

0 0ft m

1

1

2

2

3

3

4

4

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Ele

va

tio

n (

m)

Blo

ws p

er

15

0 m

m


St. John's Harbour



St. John's, NL

3129

July 21, 2018



DCPT:1 for 0.31 m / 1 / 1 for 0.23 m

/ 1 for 0.13 m / 1 / 1 / 1 / 1 / 1 / 2 / 1 for 0.31 m

/ 1 / 1 for 0.46 m / 1 for 0.46 m

/ Sank 1.33 m under own weight

End of Borehole

-12.5

-15.1

-19.7

1

111111112

1

1

1

1

0

20 40 60 80



Geodetic


Client:

Location:

Project No:

Date:


154 Major's Path


Phone: (709) 739-7270

Fax: (709) 753-5101

Drilling Method:

Driller:

Datum:

Sheet: 2 of 2

De

pth

33

11

34

12

35

13

36

14

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Ele

va

tio

n (

m)

Blo

ws p

er

15

0 m

m




St. John's, NL

3129

August 1 , 2018

0 m LNT 0

20 40 60 80



Geodetic


Client:

Location:

Project No:

Date:


154 Major's Path


Phone: (709) 739-7270

Fax: (709) 753-5101

Drilling Method:

Driller:

Datum:

Sheet: 1 of 2

De

pth

0 0ft m

1

1

2

2

3

3

4

4

5

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Ele

va

tio

n (

m)

Blo

ws p

er

15

0 m

m


St. John's Harbour



St. John's, NL

3129

August 1 , 2018



DCPT:11 / 5 / 5 / 11

/ 12 / 51 for 0.0 m (Refusal)

End of Borehole

-14.2

-16.3

-17.1

1155111251

20 40 60 80



Geodetic


Client:

Location:

Project No:

Date:


154 Major's Path


Phone: (709) 739-7270

Fax: (709) 753-5101

Drilling Method:

Driller:

Datum:

Sheet: 2 of 2

De

pth

33

11

34

12

35

13

36

14

37

15

38

16

39

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18

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Ele

va

tio

n (

m)

Blo

ws p

er

15

0 m

m


APPENDIX C

2016 Prosser’s Rock Geotechnical Investigation

Geotechnical Factual Report March 2016

Prosser’s Rock, St. John’s Harbour, NL

Fracflow Consultants Inc., File 3078 i

Preface

AFN Engineering retained Fracflow Consultants Inc. on behalf of Fisheries and Oceans Canada

under Contract F6140-150057 dated January 29, 2016 to undertake a marine geotechnical site

investigation at the Prosser’s Rock Small Boat Basin, St. John’s Harbour, NL.

The proposed scope of work for the Prosser’s Rock project consisted of drilling and sampling

three (3) barge based geotechnical boreholes (Figure 1, Appendix A). The field work was

conducted on February 22, 24, 25, and 29, 2016. Due to high winds and wave action in the

Harbour, work could not be conducted on the barge on February 23, 26, 27, or 28, 2016. The

field work for these investigations utilized a Foremost Mobile B-47 geotechnical drill rig at the

approximate locations specified by AFN Engineering. Split-spoon sampling and Standard

Penetration Tests (SPTs) were conducted using a NW/NQ diamond drill string in each borehole

at the standard 1.5 m interval.

A visual inspection of the subsurface soil conditions encountered, based on the split-spoon

samples and overburden core that was recovered during the field program, was used to describe

the soil conditions at the site. The end of hole depths of the three (3) boreholes ranged from -

8.71 m LNT in BH3 to -10.42 m LNT in BH1. A 30 cm long void within the bedrock was

encountered in BH2 which is common in the near surface bedrock in this area. In this location,

the sedimentary bedrock strikes sub-parallel to the shoreline and dips approximately 65 degrees

into the hillside or shoreline.

The overburden, based on the three (3) boreholes that were completed as part of this geotechnical

investigation, can be summarized as a layer of fill consisting of gravel, cobbles ranging from

10 cm to 15 cm cored length, and boulders ranging from 24 cm to 47 cm cored length from ocean

bottom to the original ocean bottom sediments. The original harbour sediments consists of a layer

of black, organic rich, fine sand that was encountered in boreholes BH1 and BH3, at



Fracflow Consultants Inc., File 3078 ii

-4.68 m LNT and -5.51 m LNT respectively. In BH2, only a few centimetres of the black organic

sediments were recovered in the split spoon at -5.75 m LNT. Overburden thicknesses ranged

from 2.24 m in BH3 to 7.72 m in BH1. Bedrock was encountered in all three boreholes, at

elevations ranging from -5.30 m LNT in BH3 to -8.87 m LNT in BH1. The variable nature or

rapid changes in bedrock elevation at this site is noted.



Fracflow Consultants Inc., File 3078 iii

TABLE OF CONTENTS

Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i

List of Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv

List of Appendices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv

1.0 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

2.0 SITE DESCRIPTION AND GENERAL GEOLOGY . . . . . . . . . . . . . . . . . . . . . . . . . 2-1

3.0 INVESTIGATIVE PROCEDURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1

4.0 SUBSURFACE CONDITIONS AND CHARACTERIZATION . . . . . . . . . . . . . . . . 4-1

4.1 Soil Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1

4.2 Bedrock Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2

5.0 REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1



Fracflow Consultants Inc., File 3078 iv

List of Tables

Table 1.1 Summary of geotechnical investigations at Prosser’s Rock, St. John’s Harbour,

NL.

Table 1.2 Summary of marine sediment sampling at Prosser’s Rock, St. John’s Harbour,

NL.

List of Appendices

Appendix A Figures

Appendix B Borehole Logs




1.0 INTRODUCTION

AFN Engineering retained Fracflow Consultants Inc. on behalf of Fisheries and Oceans Canada

to undertake a marine geotechnical site investigation at the Prosser’s Rock Small Boat Basin,

St. John’s Harbour, NL.

The proposed scope of work for the Prosser’s Rock project consisted of drilling and sampling

three (3) barge based geotechnical boreholes. The borehole locations are shown on the site plan

in Figure 1, Appendix A. A summary of the geotechnical field work conducted is shown in

Table 1.1. One (1) marine sediment environmental sample was taken from BH1. A summary of

the marine sediment sampling is shown in Table 1.2. The sediment sample was delivered to

Maxxam Analytics Inc. in St. John’s on behalf of DFO.

This report contains a factual presentation and full disclosure of all findings of the subsurface

investigation. The following sections provide: (1) a description of the site and the general

geology of the area; (2) a summary of the investigative procedures used; and (3) a detailed

description of the subsurface soil conditions. Appended to this report is a site plan showing the

locations for each borehole, the detailed geotechnical logs for each borehole, and photos of the

drill core recovered.




Table 1.1 Summary of geotechnical investigations at Prosser’s Rock, St. John’s Harbour,

NL.

Borehole ID

Overburden

Drilled

(m)

Bedrock

Drilled

(m)

Total Depth

Drilled

(m)

SPT & Split-

spoon Samples

Attempted

Split-spoon

Samples Tested

BH1 7.72 1.55 9.27 6 0

BH2 5.98 1.88 7.86 3 0

BH3 2.24 3.41 5.65 3 0

Total 15.94 6.84 22.78 12 0

Table 1.2 Summary of marine sediment sampling at Prosser’s Rock, St. John’s Harbour,

NL.

Borehole

No.

Depth to Start of

Split Spoon

Relative to LNT

(m)

Depth to End of

Split Spoon

Relative to LNT

(m)

Split-spoon

Sample

Attempted

Sample ID’s Samples

Analysed

BH1 -4.680 -4.73 1 BH1-SS4 1




2.0 SITE DESCRIPTION AND GENERAL GEOLOGY

The Prosser’s Rock Small Boat Basin is located on the south side of the mouth of the St. John’s

Harbour, adjacent to Fort Amherst Road.

Overburden in the area is characterized by till veneer and moraine of varying thickness overlying

bedrock (Water Resources Division, 1984). Bedrock in the area consists of sandstones, siltstones,

mudstones, and conglomerates of the Signal Hill Formation (King, 1990).




3.0 INVESTIGATIVE PROCEDURES

At the Prosser’s Rock site, the project consisted of drilling and sampling three (3) barge based

boreholes. The field work for these investigations utilized a Foremost Mobile B-47 geotechnical

drill rig mounted on a barge at the locations shown in Figure 1, Appendix A.

Overburden material was drilled using ‘NW’ (OD 88.9 mm, ID 76.2 mm) flush joint casing and

“NQ” (OD 69.9 mm, ID 60.3 mm) diamond drill string. Soil samples were collected using a

51 mm OD, 610 mm long, split-spoon sampler. In conjunction with this split-spoon soil

sampling, SPTs were performed to estimate relative soil densities. The standard procedure is to

drive each split-spoon into the ground using a 63.5 kg weight falling a distance of 760 mm. The

number of blows is recorded for each 150 mm the split-spoon is advanced. After the first

150 mm advance, a N-value is calculated as the sum of the blow counts required to drive the

spoon an additional 300 mm (i.e., the sum of the second and third set of blow counts). The

calculated N-value is a direct reflection of the relative density of the soil strata as defined in the

Canadian Foundation Engineering Manual (Canadian Geotechnical Society, 1992).

One (1) marine sediment environmental sample was collected from BH1 from material recovered

in the split spoon from -4.68 m LNT to -4.73 m LNT. The sample was an organic rich black fine

sand. This sample was stored on ice and submitted to Maxxam Analytics in St. John’s on behalf

of DFO.

Both the soil samples and rock cores were logged and labelled in the field immediately after

collection. Soil samples were stored in moisture proof containers and rock cores were stored in

wooden core boxes in the field. All soil and rock samples were returned to Fracflow’s office.

Sample amounts recovered from the split spoons were insufficient to conduct mechanical grain

size analysis. The soil and rock core samples are stored by Fracflow for a two-year period.




4.0 SUBSURFACE CONDITIONS AND CHARACTERIZATION

Subsurface characterization is based on the field data collected from the three (3) vertical

boreholes that were completed at this site. Data collection included split-spoon sampling while

drilling in conjunction with the SPTs. A description of the overburden is provided below.

Photographs of the overburden cobbles and boulders and core recoveries from each borehole are

provided in Figure 2, Appendix A. Detailed logs of the geological conditions at each borehole

location are provided in Appendix B.

4.1 Soil Description

Sample material recovered from the split spoons was insufficient to conduct mechanical grain

size analysis. Overburden was therefore characterized from the gravel, cobbles, and boulders

recovered from drilling.

The overburden, based on the three (3) boreholes that were completed as part of this geotechnical

investigation, can be summarized as a layer of fill consisting of gravel, cobbles ranging from

10 cm to 15 cm cored length, and boulders ranging from 24 cm to 47 cm cored length from ocean

bottom to the original harbour sediments. The original harbour sediments consist of a layer of

black organic rich fine sand that was encountered in boreholes BH1 and BH3, at -4.68 m LNT

and -5.51 m LNT respectively. A few centimetres of this organic rich sediment was encountered

in BH2 at a depth of -5.75 m LNT. Overburden/fill thicknesses ranged from 2.24 m in BH3 to

7.72 m in BH1.




4.2 Bedrock Description

Bedrock in the area consists of sandstones, siltstones, mudstones, and conglomerates of the

Signal Hill Formation (King, 1990).

Bedrock was encountered in all three (3) boreholes. Bedrock elevation ranged from -5.30 m LNT

in BH3 to -8.87 m LNT in BH1. Bedrock was a fine grained red sandstone with Rock Quality

Designation (RQD) values ranging from 0% to 100%. Bedrock recoveries ranged from 91% to

100%.




5.0 REFERENCES

Canadian Geotechnical Society (CGS), 1992, Canadian Foundation Engineering Manual, 3rd

Edition, Technical Committee on Foundations, 512 p.

King, A.F., 1990, Geology of the St. John’s area, parts of NTS sheets 1N/7E, 1N/7F, 1N/7G,

1N/10B, A, 1N/10C, 1N/10D, 1N/10F, and 1N/10G, Map 90-120, Report 90-02,

Newfoundland and Labrador Department of Mines and Energy, Geological Survey

Branch.

Water Resources Division, 1984. Hydrogeology of the Avalon Peninsula Area, Water Resources

Report 2-6, Water Resources Division, Newfoundland Department of Environment.

APPENDIX A

Figures

Hole ID: BH1

Hole ID: BH2

Hole ID: BH3

Figure 2 Photographs of core recovered during drilling from borehole BH1, BH2, and BH3.

APPENDIX B

Borehole Logs

BH1

3078

Marine Geotechnical Investigation

DFO

Prosser's Rock, St. John's Harbour February 29, 2016

0 m LNT

Harbour Bottom (-1.150 m LNT).

SPT: 5 / 6 / 13 / 4.Rocks in split spoon shoe.

Overburden: gravel, cobble (10 cm).

SS2: "N" Value = 52; Recovery = 0%.SPT: 1 for 0.03 m / 52 for 0.0 m, bouncing

(Refusal).No sample recovery.

Overburden: gravel, cobble (12 cm), boulder(47 cm).

SPT: 13 / 6 / 17 / 13.No sample recovery.

Overburden: gravel.


(Refusal).Black organic rich sand. Sample BH1-SS4

collected for laboratory analysis by Maxxam.

Overburden: gravel, boulder (44 cm).

0

-1.15

-1.76

-2.3

-3.26

-3.82

-4.68

SS

OB

SS

OB

SS

OB

SS

1

--

2

--

3

--

4

19

52

23

52

4

32

0

53

0

7

100

59

20 40 60 80

NW casing / NQ coring

Formation Drilling Ltd

LNT

Log of Borehole:

Project No:

Project:

Client:

Location: Date:

Fracflow Consultants Inc.154 Major's PathSt. John's, NL A1A 5A1Phone: (709) 739-7270Fax: (709) 753-5101

Drilling Method:

Driller:

Datum:

Sheet: 1 of 2

SUBSURFACE PROFILE SAMPLE

Depth

belo

wLN

T

0 0ft m

1

1

2

2

3

3

4

4

5

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

Sym

bol


Ele

vatio

n (

m)

Sam

ple

Typ

e

Sam

ple

No.

"N"

Valu

e

Reco

very

(%

)

RQ

D (

%)


BH1

3078


DFO




Overburden: gravel, boulders (26 cm, 33 cm).



Overburden: gravel.

Bedrock: fine grained sandstone.

End of Borehole

-6.31

-8.05

-8.87

-10.4

OB

SS

OB

SS

OB

RC

RC

--

5

--

6

--

--

--

52

52

59

0

31

0

35

92

98

65

0

20 40 60 80



LNT

Log of Borehole:

Project No:

Project:

Client:

Location: Date:


Drilling Method:

Driller:

Datum:

Sheet: 2 of 2


Depth

belo

wLN

T

20

7

21

8

22

9

23

10

24

11

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

Sym

bol


Ele

vatio

n (

m)

Sam

ple

Typ

e

Sam

ple

No.

"N"

Valu

e

Reco

very

(%

)

RQ

D (

%)


BH2

3078


DFO


0 m LNT


SPT: 1 / 1 / 1 / 1.No sample recovery.

SPT: 2 / 6 / 7 / 11.Rock in split spoon shoe.

Overburden: gravel.

SPT: 3 / 3 / 6 / 12.Rock chips in split spoon shoe.

0

-2.35

-2.96

-3.34

-3.94

-5.17

-5.75

SS

OB

SS

OB

SS

1

--

2

--

3

2

13

9

0

0

0

47

0

20 40 60 80



LNT

Log of Borehole:

Project No:

Project:

Client:

Location: Date:


Drilling Method:

Driller:

Datum:

Sheet: 1 of 2


Depth

belo

wLN

T

0 0ft m

1

1

2

2

3

3

4

4

5

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

Sym

bol


Ele

vatio

n (

m)

Sam

ple

Typ

e

Sam

ple

No.

"N"

Valu

e

Reco

very

(%

)

RQ

D (

%)


BH2

3078


DFO


Overburden: gravel, boulders (24 cm, 28 cm).

Overburden: gravel, wood fragments.


End of Borehole

-7.11

-8.32

-10.2

OB

OB

RC

RC

--

--

--

--

38

17

100

91

100

36

20 40 60 80



LNT

Log of Borehole:

Project No:

Project:

Client:

Location: Date:


Drilling Method:

Driller:

Datum:

Sheet: 2 of 2


Depth

belo

wLN

T

20

7

21

8

22

9

23

10

24

11

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

Sym

bol


Ele

vatio

n (

m)

Sam

ple

Typ

e

Sam

ple

No.

"N"

Valu

e

Reco

very

(%

)

RQ

D (

%)


BH3

3078


DFO

St. John's Harbour, NL February 22, 24, 2016

0 m LNT


SPT: 3 / 1 / 8 / 2 for 0.41 m.No sample recovery.

Overburden: gravel, cobble (15 cm).



Overburden: black fine sand, gravel.


SS3: "N" Value = 52; Recovery = 0%.SPT: 52 for 0.0 m, bouncing (Refusal).

No sample recovery.

0

-3.06

-3.92

-4.22

-5.3

-5.51

SS

OB

SS

OB

RCSS

1

--

2

--

--3

9

52

52

0

43

0

30

970

97

51

20 40 60 80



LNT

Log of Borehole:

Project No:

Project:

Client:

Location: Date:


Drilling Method:

Driller:

Datum:

Sheet: 1 of 2


Depth

belo

wLN

T

0 0ft m

1

1

2

2

3

3

4

4

5

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

Sym

bol


Ele

vatio

n (

m)

Sam

ple

Typ

e

Sam

ple

No.

"N"

Valu

e

Reco

very

(%

)

RQ

D (

%)


BH3

3078


DFO

St. John's Harbour, NL February 22, 24, 2016


End of Borehole

-8.71

RC

RC

RC

RC

RC

--

--

--

--

--

97

100

92

100

100

51

100

32

39

100

20 40 60 80



LNT

Log of Borehole:

Project No:

Project:

Client:

Location: Date:


Drilling Method:

Driller:

Datum:

Sheet: 2 of 2


Depth

belo

wLN

T

20

7

21

8

22

9

23

10

24

11

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

Sym

bol


Ele

vatio

n (

m)

Sam

ple

Typ

e

Sam

ple

No.

"N"

Valu

e

Reco

very

(%

)

RQ

D (

%)


appendix b: geotechnical report

Documents