2 Ground conditions

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REPORT

CLIENT

Bremangerlandet vindpark AS

SUBJECT

Engineering Geological Report

DATE: / REVISION: September 20, 2019 /00 DOCUMENT CODE: 10211972-01-RIGberg-RAP-001

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This report has been prepared by Multiconsult on behalf of Multiconsult or its client. The client’s rights to the report are regulated in the relevant assignment agreement. If the client provides access to the report to third parties in accordance with the assignment agreement, the third parties do not have other or more extensive rights than the rights derived from the client’s rights. Any use of the report (or any part thereof) for other purposes, in other ways or by other persons or entities than those agreed or approved in writing by Multiconsult is prohibited, and Multiconsult accepts no liability for any such use. Parts of the report are protected by intellectual property rights and/or proprietary rights. Copying,

distributing, amending, processing or other use of the report is not permitted without the prior written consent from Multiconsult or other holder of such rights.

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REPORT

PROJECT

Bremangerlandet vindkraftverk DOCUMENT CODE 10211972-01-RIGberg-RAP- 001

SUBJECT Engineering Geological Report ACCESSIBILITY Open

CLIENT Bremangerlandet vindpark AS PROJECT MANAGER Asle Juul

CONTACT Stig Svalheim PREPARED BY Håvard Barkved

COORDINATES SONE: 32N EAST: 292559 NORTH: 6865636 RESPONSIBLE UNIT Multiconsult Norge AS GNR./BNR./SNR. X / X / X /

SUMMARY

Multiconsult Norge AS have conducted engineering geological mapping of 18 planned turbine locations at Bremangerlandet wind park. The study aims to describe the geology and conduct a preliminary evaluation of the suitability of the locations for rock anchored turbine foundations.

The rock types in the project area are granite, amphibolite and various types of gneisses. The joint pattern varies locally due to different deformation properties.

Groundwater level is unknown in the project area.

Both rock mass properties and global slope stability has been evaluated. It is recommended to move T06 approximately 10 m to avoid proximity to a steep cliff.

Planned locations for T02, T03, T04, T05, T07, T08 and new, recommended location for T06, are considered suitable for rock-anchored foundation.

Planned locations T01, T09, T10, T11, T12, T13, T14, T15, T16, T17 and T18 require more detailed investigations considering rock mass quality. The rock mass at these 11 turbine locations are either weathered at surface or covered by soil/vegetation. It is likely that rock suitable for rock-anchored foundation will be found after the uppermost weathered rock is removed. Core drilling can be performed to evaluate the rock mass quality at T01, T09, T10, T11, T12, T13, T14, T15, T16, T17 and T18. Drilling can be combined with groundwater monitoring.

Alternatively, the rock can be investigated during construction. A flexible design can account for different ground conditions.

The mechanical properties of rock can vary in depth. Rock mass parameters at all 18 locations must be evaluated, and adjusted if necessary, after excavation.

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Engineering geological report TABLE OF CONTENTS

1 Scope of work

1.1 Introduction

Bremangerlandet vindpark AS is planning a wind park at Bremangerlandet in the municipality of Bremanger in Sogn og Fjordane. The planned wind park consists of 18 wind turbines (Figure 1-1).

Figure 1-1 Overview of project area, with planned turbine locations indicated. Based on map data from Kartverket (2019).

1.2 Purpose

Multiconsult Norge AS have conducted a field study of the planned turbine locations in the wind

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Engineering geological report 2 Ground conditions

1.3 Basis for the evaluations

Evaluations presented in this report are based on both fieldwork and map studies. Fieldwork was conducted the 28^th and 29^th of August 2019 by Håvard Barkved from Multiconsult Norge AS. Lars Johan Sivertsen from Vestavind Energi AS participated in parts of the first day of fieldwork. The turbine locations were found using the mobile application ArcGIS Collector. The margin of error from the GPS is plus/minus 6 m or better.

In addition to the field mapping, the following resources have been used as basis for this report:

• NGU (Geological Survey of Norway) Bedrock Map N250 (www.ngu.no)

• NGU Quaternary Map (www.ngu.no)

• Topographic maps from Kartverket (www.kartverket.no)

• Ortofoto and terrain models from Kartverket (www.kartverket.no)

• Slope map from NGI (Norwegian Geotechnical Institute) (www.ngi.no)

• NVE (The Norwegian Water Resources and Energy Directorate) Faresonekart (www.nve.no)

• Turbine coordinates from Vestavind Energi AS

2 Ground conditions

2.1 Topography and soil

The topography of the project area varies between approximately 250 and 650 meters above sea level. In the western part the mountain Steinfjellet (637 masl.) dominates. East of Steinfjellet there is a plateau between 530 and 400 masl., where the terrain slopes gently towards northeast (Figure 2-1). In the northeastern part of the project area the terrain rises up to a mountain ridge, with mountains of elevation around 500 masl. North of this ridge the terrain slopes steeply into the fjord (Fåfjorden). The southeastern part of the project area is separated from the plateau by a NE-SW trending valley, Klungresetdalen. Southeast of Klungresetdalen (approx. 250 masl) the terrain rises to around 350 masl.

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Figure 2-1 Aerial photo of the project area. Scale bar is 0.6 km.

Several different soil types can be found in the project area. According to the Geological Survey of Norway (NGU) there are moraine (of variable thickness), peat and marsh, deposits of weathered material and exposed bedrock in the project area (Figure 2-2). The western part of the project area is mostly dominated by moraine and peat and marsh. South of Steinfjellet there is some exposed bedrock. Exposed bedrock dominates the northeastern part of the project area, which also is the situation in the eastern and southeastern part.

The distribution between exposed bedrock and soil cover shown in Figure 2-2 was mostly verified by field mapping. Soil cover conditions at each turbine location will be described further in section 4.1.

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Figure 2-2 Soil map of the project area, based on map data from NGU (2019).

2.2 Hydrogeology

There is a small lake (Steinfjellvatnet) located 530 masl., east of Steinfjellet. The river of Trettelva runs from Steinfjellvatnet towards northeast. Some small lakes/ponds are found in the eastern part of the project area.

Water flow in the rock mass are normally limited to joints in the rock mass, as the rock material itself often is considered impervious (Nilsen, 2016). Some water bearing joints must be expected.

There are no known measurements of the ground water level in the area.

2.3 Geology

2.3.1 Rock type

The bedrock of Bremangerlandet is of Precambric to Devonian age. The majority of the bedrock in the project area consists of metasupracrustals of Precambric age. This is metamorphosed rocks, originally deposited near surface. According to Figure 2-3, these rocks are found as dioritic to granitic gneisses and migmatite in the project area. South of the mountain massif there are both

amphibolite/mica schist and quartzite, rocks of Cambro-Silur age (NGU, 2019).

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Figure 2-3 Bedrock map of the project area, made with N250 map data from NGU (2019).

With exception of some amphibolite and quartzite in the southeastern part (around T01), gneisses and granites were found throughout the project area during the field study. At the plateau in the western part of the project area there is found a mica-rich, schistose gneiss. A blocky granite was locally found in the northeastern part. Also east of Klungresetdalen a mica-rich, schistose gneiss was found.

2.3.2 Jointing

Different kind of processes have caused jointing of the rock mass. Differences in deformation properties cause different jointing character. The joint pattern shows local variations. The spread of jointing in the mapped gneisses is illustrated in Figure 2-4.

Following joint sets were registered for the gneisses in the project area, with dominating dip direction/dip indicated:

• Foliation: N160E-N180E/35-55°

• Joint set 1: N080E-N090E/65-90°

• Joint set 2: N100E-N120E/70-90°

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Engineering geological report 3 Previous experience

Figure 2-4 Joint rosette, showing the strike of 24 mapped joints in gneisses in the project area.

Foliation joints are observed in gneiss outcrops throughout the project area, while one or both of the two other joint sets also are observed at each gneiss outcrop.

Granite has also been found in the project area. The mapped granite outcrops show different joint pattern than the gneisses. Three joint sets are observed in the mapped granite outcrops.

3 Previous experience

There is a wind measuring mast at Bremangerlandet, with location shown in Figure 3-1. According to Vestavind Energi AS, the rock mass was considered not suitable for rock-anchored foundation of the mast. As the rock mass was relatively weathered, gravity foundation was used instead. It is not known how deep into the ground the rock mass quality was evaluated.

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Engineering geological report 4 Engineering Geological Description

Figure 3-1 Placement of wind measuring mast at Bremangerlandet. Planned turbine locations indicated.

4 Engineering Geological Description

4.1 Description of turbine locations

4.1.1 T01

Located on a flat plateau (Figure 4-1). Groundwater level is unknown.

The rock type at turbine location is mafic, probably amphibolite. The rock mass is highly weathered and rust staining is found near surface. Quartzite is found approx. 50 meters south of T01, while gneiss is found north of the location.

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Figure 4-1 Approximate location of T01. Photo taken looking towards NE.

4.1.2 T02

Located in a relatively flat area (Figure 4-2). Groundwater level is unknown, but there is a pond located 25 m from T02. The pond is located 4 m below foundation elevation.

The rock type is a grey and white schistose gneiss, rich of mica. Locally red feldspar grains occur.

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4.1.3 T03

There is no exposed rock at T03. Located in a flat area (Figure 4-3). Groundwater level is unknown.

The area is vegetated of grass and heather, with some rock outcrops in the area.

There are rock type variations from one outcrop to another, going from south to north across the foliation (which trends N065E). The rock type is a gneiss, varying from relatively massive to more schistose. The rock mass shows some surface weathering.

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Figure 4-3 Approximate location of T03. Photo taken looking towards E.

4.1.4 T04

Located in a relatively flat area (Figure 4-4). Groundwater level is unknown.

The rock type is a grey and white, schistose gneiss with high mica content. Quartz layers stand out due to higher erosional resistance.

Figure 4-4 Approximate location of T04. Photo taken looking towards west.

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4.1.5 T05

Located in a gently sloping terrain (Figure 4-5). Groundwater level is unknown.

The rock type is a red and grey granite, with red feldspar grains. The rock mass shows a blocky nature.

4.1.6 T06

Located close to a ridge, in a terrain sloping towards south (Figure 4-6). Approx. 10 m north of T06 the terrain dips steeply towards north. A slope map is shown in Figure 4-7, but due to map resolution all slope details are not shown.

Groundwater level is unknown.

The rock type is a red and grey foliated granite/augen gneiss, with red feldspar grains. Less blocky rock mass than at T05.

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Figure 4-7 Slope map for the terrain at T06. Approx. location of T06 is indicated. Based on map from NGI (2019).

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4.1.7 T07

Located in a flat area (Figure 4-8). Groundwater level is unknown.

The rock type is mostly a red and grey granite/granitic gneiss, but with local variations. The rock mass some places show higher degree of metamorphosis, and fold structures indicate that the rock has undergone high temperatures and melting.

4.1.8 T08

Located in a flat area (Figure 4-9). Groundwater level is unknown.

The rock type is mostly a grey/white, schistose gneiss. Some rust staining along foliation planes, near surface. Relatively jointed near surface, but better rock mass quality is expected deeper into the ground. Locally a more blocky augen gneiss, with red feldspar grains, is found.

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4.1.9 T09

There was not found exposed bedrock at location. The area is covered by vegetation. Located in a gently sloping area (Figure 4-10). Groundwater level is unknown.

An outcrop is found approx. 100 m from T09. Rock type at investigated outcrop is a pink and grey, schistose gneiss. Some layers of high mica content occur.

Figure 4-10 Approximate location of T09. Photo taken looking towards W.

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4.1.10 T10

There was not found exposed bedrock at location. The location area is covered by vegetation.

An outcrop is found approx. 100 m from T10, where the rock type is a red and grey, schistose gneiss.

4.1.11 T11

There was not found exposed bedrock at location, covered by vegetation/peat/marsh. Located in a relatively flat area (Figure 4-12). Groundwater level is unknown.

An outcrop is found approx. 100 m from T11. The rock type at investigated outcrop is a red and grey, schistose gneiss.

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4.1.12 T12

There was not found exposed bedrock at T12. The area is covered by peat/marsh. Located in a relatively flat area (Figure 4-13). Groundwater level is unknown, but several small streams are found nearby. The river Trettelva is located 170 m towards north.

No rock outcrop was found nearby, only moraine deposits/rock boulders.

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4.1.13 T13

There was not found exposed bedrock at location. The area is covered by a combination of vegetation, peat/marsh and moraine deposits. The turbine location lies in a flat area. The location lies 70 m southwest of the lake Steinfjellvatnet. As the turbine location lies 3 m above the lake, groundwater can be expected close to surface at T13. Surface water is also observed 20 m towards east, approx. 1 m below foundation level (Figure 4-14).

No rock outcrop was found nearby T13.

4.1.14 T14

There was not found exposed bedrock at location. The area is covered by vegetation and some rock boulders/moraine deposits. T14 is located in a flat area (Figure 4-15). Groundwater level is unknown.

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4.1.15 T15

There was not found exposed bedrock at location, as the area is covered by vegetation. Location in a gently sloping terrain (Figure 4-16). Groundwater level is unknown, but some streams observed nearby.

4.1.16 T16

There was not found exposed bedrock at location. The area is covered by vegetation. Some rock boulders and moraine deposits are found. T16 is located in a gently sloping terrain (Figure 4-17).

Groundwater level is unknown, but a stream is located 20 m towards south.

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Figure 4-17 Approximate location of T16. Photo taken towards SW (Steinfjellet).

4.1.17 T17

Located in a relatively flat terrain (Figure 4-18). Groundwater level is unknown.

The rock type is a schistose, white/grey gneiss. The rock is highly weathered along foliation planes.

Figure 4-18 Approximate location of T17. Photo taken towards NW.

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4.1.18 T18

The rock type is a white and grey, schistose gneiss. The rock is highly weathered along foliation planes, similar to the rock type at T17.

4.2 Rock Mass Rating (RMR)

The RMR system, developed by Bieniawski (1989), is an empirical classification system for rock mass quality. Different rock mass characteristics are given scores based on observations, and the sum of the scores gives an RMR-value for the rock mass at a given location. Based on the RMR value, the rock mass is classified either as “very good”, “good”, “fair”, “poor” or “very poor”.

One of the evaluated characteristics is “Rock Quality Designation” (RQD), defined as the sum of core pieces longer than 10 cm in percentage of the total length of the core. Six characteristics are related to the discontinuities in the rock mass – spacing, persistence, separation, roughness, infilling and weathering. In addition to this, the groundwater conditions and the strength of intact rock mass are taken into consideration. The RMR system also includes a rating adjustment for discontinuity orientations.

4.2.1 Assumptions of RMR estimations

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Empirical values from similar rock types have been used as input for UCS values of intact rock material (Table 4-1). The lower limits in the table are used when the strength of intact rock material are assumed for the different rock types.

Table 4-1 Typical UCS values, presented by SINTEF (n.d.). The rating of “Strength of intact rock material” (in the RMR system) used for the different rock types are indicated in the third column.

Rock type Typical UCS values [MPa] Rating in RMR classification

Granite 100-230 12

Augen gneiss 100-230 12

Mica gneiss 60-100 7

Amphibolite 80-170 7

Discontinuity separation have been assumed to be narrow or closed deeper into the rock mass, even if the discontinuities locally show some separation at surface.

In cases where no infilling has been observed at surface, no infilling has been assumed also deeper into the rock mass. There is a possibility that infilling have been washed out at surface and not deeper into the rock mass.

For the purpose of estimating an representative RMR for the rock mass, groundwater conditions have been assumed “completely dry”, even if presence of groundwater can be expected.

The calculated RMR values have not been adjusted for discontinuity orientations.

4.2.2 Estimated RMR characteristics

Table 4-2 shows rock mass characteristics from the different locations, based on field investigations and assumptions mentioned in section 4.2.1. Based on the characteristics presented in the table, a rock mass rating (RMR) of the rock mass have been estimated.

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Engineering geological report 5 Engineering Geological Evaluations

Table 4-2 Rock mass characteristics from field investigations. RMR score for each characteristic is indicated in parentheses.

Location Rock type RQD [%]

Spacing [m]

Length [m]

Separation

[mm] Roughness Infilling Weathering Groundwater RMR

T01 Amphibolite Not evaluated

T02* Schistose

gneiss 85 (17) 0.15-1 (8) 10 (1) Assumed none (6)

Slightly

rough (3) None (6) Moderately (3) Completely dry (15) 66

T03 Schistose

gneiss 80 (17) 0.1-0.4

(8) >5 (2) Assumed none (6)

Slightly

T04 Schistose

gneiss 85 (17) 0.3-1 (10) 10 (1) Assumed none (6)

Slightly

T05 Granite 95 (20) 0.3-1 (10) >15 (1) Assumed none (6)

Slightly

T06 Augen

gneiss 85 (17) 0.1-0.4 (8)

> 10 (1)

Assumed none (6)

Slightly

T07 Granitic

gneiss 85 (17) 0.15-0.8

(8) >10 (1) Assumed none (6)

Slightly

T08** Schistose

gneiss 75 (13) 0.1-0.5

(8) >7 (1) Assumed none (6)

Slightly

T09 Not evaluated

T10 Not evaluated

T11 Not evaluated

T12 Not evaluated

T13 Not evaluated

T14 Not evaluated

T15 Not evaluated

T16 Not evaluated

T17 Schistose

gneiss Not evaluated

T18 Schistose

gneiss 75 (13) 0.05-0.5

(8) >10 (1) Assumed none (6)

Slightly

rough (3) None (6) Highly weathered

(1) Completely dry (15) 60

* No outcrop at location. Mapped on nearby rock mass.

** A relatively low RMR because of jointed rock mass near surface. Conditions expected to be better deeper into the ground.

5 Engineering Geological Evaluations

5.1 Evaluations of turbine locations

5.1.1 T01

The terrain is relatively flat and the global stability at the turbine location is considered adequate.

The rock mass quality has not been evaluated. The rock mass is highly weathered. Further investigations are necessary to evaluate whether the rock quality is suitable for rock-anchored foundation.

5.1.2 T02

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The rock mass quality is good. Estimated RMR is 66. The rock quality is considered suitable for rock- anchored foundation.

5.1.3 T03

5.1.4 T04

5.1.5 T05

The terrain is not very steep and the global stability at the turbine location is considered adequate.

5.1.6 T06

The planned turbine location is approx. 10 m from a cliff, described in section 4.1.6. The stability near the cliff is uncertain and it is recommended to move the turbine location approximately 10 m

towards south. (Figure 5-1). The terrain at recommended location dips approx. 20° towards southwest.

The global stability at new, recommended location is considered adequate.

We have not considered the overall stability of the mountainside with regards to big avalanches.

According to NVE (2019), Oldeidsmannen is not identified as an unstable mountain massif.

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Figure 5-1 Planned T06 location and recommended new location of T06.

5.1.7 T07

5.1.8 T08

5.1.9 T09-T16

The terrain at locations T09-T16 is relatively flat and the global stability at the turbine locations is considered adequate.

The rock mass quality has not been evaluated, as no outcrop was found at these locations. Further investigations are necessary to evaluate whether the rock quality is suitable for rock-anchored foundation.

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Engineering geological report 6 Conclusions

At the surface the rock mass is highly weathered, similar to T18. The rock mass quality is expected to be better after removal of the weathered rock. Rock of a sufficient quality for rock anchoring is probable, but further investigations is necessary to confirm.

5.1.11 T18

The terrain is relatively flat and the global stability at the turbine location is considered sufficient.

At the surface the rock mass is highly weathered. Estimated RMR is 60, which is classified as “fair”

rock mass. The rock mass quality is expected to be better after removal of the weathered rock. Rock of a sufficient quality for rock anchoring is probable, but further investigations is necessary to confirm.

5.2 Uncertainties

The rock mass is only mapped at surface conditions. The rock mass properties can vary with depth.

At several turbine locations the rock mass also show local variations, and vegetation/soil cover limits access of information. Assumptions of the RMR calculations are mentioned in 4.2.1. The validity of these assumptions must be assessed during excavation. Estimated rock mass characteristics must then be verified, and adjusted if necessary.

6 Conclusions

The rock mass quality at turbine locations T02, T03, T04, T05, T06, T07 and T08 is considered suitable for rock-anchored foundation.

T06 is recommended moved approximately 10 m to ensure the global stability of the foundation.

Turbine locations T01, T09, T10, T11, T12, T13, T14, T15, T16, T17 and T18 will require more detailed evaluations considering rock mass quality. These 11 locations have either highly weathered rock outcrops at the surface or are covered by soil/vegetation. Based on the rock outcrops nearby and the terrain features in the area, it is likely that suitable rock will be found after the uppermost weathered rock is removed.

At the locations with highly weathered rock outcrops and/or soil cover, core drilling can be

performed to evaluate the suitability of the rock mass for rock-anchored foundation. Probe drilling or geophysical investigations can be performed to evaluate the soil thickness, but will not give sufficient information to evaluate the rock mass quality. If drilling is performed, piezometers should be

installed to monitor groundwater level.

Alternatively, the rock can be mapped during construction and a flexible design can account for different ground conditions. The last alternative is what is normally been done in Norwegian wind park projects.

7 Literature

- Bieniawski, Z. T. (1989) Engineering rock mass classifications. New York: Wiley - Nilsen, B. (2016) Ingeniørgeologi berg grunnkurskompendium. Trondheim: NTNU

- NVE (2019) NVE Faresoner. Available from: https://gis3.nve.no/link/?link=faresoner(accessed: 20