Compiled by: Susan Bothma

Jurgens Schoeman

February 2016

Geological and Geotechnical Investigation at Hartebeesthoek Radio Astronomy Observatory

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Contents

Introduction .................................................................................................................................................. 1

Location ......................................................................................................................................................... 2

Geology and Core Analysis ............................................................................................................................ 3

Shear box tests .............................................................................................................................................. 7

Resistivity tests ........................................................................................................................................... 10

Conclusion and recommendations ............................................................................................................. 12

Appendix A - Core Logs ............................................................................................................................... 13

Appendix B - Resistivity tests Data .............................................................................................................. 25

List of Figures

Figure 1: Location of the Drill sites at HartRAO. ........................................................................................... 2

Figure 2: Geological map of the area, HartRAO can be identified by the orange dot. Adapted from the

1:250000 Rustenburg map, Council of geo Sciences. .................................................................... 3

Figure 3: Geological legend for HartRAO Geology map. Council of Geo Sciences. ...................................... 4

Figure 4: Fissures in Andesite........................................................................................................................ 5

Figure 5: a) Mould where sample is placed, b) section view of soil sample in mould and c) setup in

laboratory ...................................................................................................................................... 7

Figure 6: Normal Stress vs Shear Stress for different samples and methods ............................................... 9

Figure 7: Resistivity instrument on site. ..................................................................................................... 10

Figure 8: Reference for the Resistivity of rocks, soils and minerals used in the classification. .................. 11

List of Tables

Table 1: Locations of the drill sites. .............................................................................................................. 2

Table 2: Water depth. ................................................................................................................................... 5

Table 3: Summary of depth Andesite and other softer rock types where found. ........................................ 6

Table 4: Moisture content at compaction .................................................................................................... 8

Table 5: Shear parameters ............................................................................................................................ 8

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Introduction

The Hartebeesthoek Radio Astronomy Observatory (HartRAO) is an astronomical research facility

located west of Johannesburg in Gauteng, South Africa.

This report was compiled on request from HartRAO. A new area of the facility is being developed and

cleared for expansion of infrastructure. A geological and geotechnical investigation was needed to

understand the properties of the soil and rock in the area where the new foundations will be placed. The

new VGOS Antenna and Russian SLR are very sensitive instruments and need stable foundations.

The drillcores where labelled as HRAP for the SLR, and HVGS for VGOS. The labels HRAP and HVGS will

be used throughout the report for easy reference to the cores.

This report should serve as a guide only to the structural engineer when the final foundations are being

designed.

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Location

Two locations in close proximity where investigated and is located in the northwestern corner of the

HartRAO site. Cores were drilled at both locations and logged to summarise the composition and

properties of the soil and rock. Figure 1 and Table 1 indicate the locations of the investigations.

Figure 1: Location of the Drill sites at HartRAO.

Table 1: Locations of the drill sites.

Drill hole Coordinates Altitude (m)

HRAP 1 25° 53’21.1895’’ S 27° 41’10.0864’’ E 1408.595

HVGS 1 25° 53’15.7620’’ S 27° 41’09.8397’’ E 1405.013

HVGS 2 25° 53’15.8707’’ S 27° 41’09.7326’’ E 1404.794

HVGS 3 25° 53’15.7241’’ S 27° 41’10.0891’’ E 1403.493

HVGS 4 25° 53’15.5440’’ S 27° 41’09.9344’’ E 1404.371

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Geology and Core Analysis

Figure 2 shows the Geological map of the area. HartRAO can be found at 25° 53' 27.1" S 027° 41' 12.7" E.

Figure 3 is the original legend for the map, adapted from 1:250000 Rustenburg, Council of Geoscience.

Figure 2: Geological map of the area, HartRAO can be identified by the orange dot. Adapted from the 1:250000 Rustenburg map, Council of geo Sciences.

4 | P a g e

Figure 3: Geological legend for HartRAO Geology map. Council of Geoscience.

A total of five boreholes were drilled at HartRAO and core samples extracted from them were described.

The location of these holes can be seen in Figure 1.

The rock types encountered was mostly that of a clay/mudstone mixture. The top layer at all five sites

where heavily eroded and weathered including roots and uneven rock fragments of different sizes. All of

the five locations are disturbed locations, and where filled up or levelled in the past and during site

preparations.

Deeper andesite rock can be found. This is a volcanic rock, meaning it crystalized above ground from

flowing lava. The colour, amount of calcite and grain size makes it possible to identify it as andesite.

The andesite is very fined grained, meaning that it cooled down quickly. Calcite was identified by the use

of hydrochloric acid (HCl) since the HCl reacts with the Calcium (Ca), or carbonates in the rock.

The area lies within the Hekpoort Formation. It is part of the greater Pretoria Group, within the

Transvaal Supergroup. The Hekpoort Formation settled in the Vaalian, 2500 - 2050 Ma ago, making it

some of the oldest rocks on Earth.

The Hekpoort Formation is characterised by volcanics, carbonates and clay/sandstone metamorphosed

materials.

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The cores exhibit closely spaced fissures which were stained/filled which is indicative of preferential

draining of water. The spacing of the fissures also renders the rock brittle which in turn made it

impossible to obtain a standard testable sample needed for unconfined compressive strength (UCS)

tests. See attached log sheets in Appendix A for locations of these fissures.

Water in the holes was also measured. This data is not very accurate as the drilling of these holes uses

water and the water found could be from the drilling. The depth of water can be seen in Table 2 below.

Table 2: Water depth in holes.

Hole Name

Hole Number

Drilled Depth [m]

Water in Hole

Depth of water [m]

Total depth of Water [m]

HRAP 1 30 No water - 0

HVGS 1 19.5 Water 17.95 1.55

HVGS 2 25.3 Water 21.95 3.35

HVGS 3 19 Water 15.75 3.25

HVGS 4 12.65 No water - 0

Full core log sheets can be found in Appendix A, and a summary of the cores is showed in Table 3. The

summary is classified as either Andesite or Other material. The other material can either be clay, sand-

or mudstone, metamorphosed or normally consolidated over time.

The ideal bedrock to place foundations or piles would be the Andesite, but metamorphosed sandstone

or shale can also be a very strong bedrock layer that can resist weathering. The detailed log sheets

indicate the locations of different metamorphosed layers.

The Andesite, as mentioned earlier, has several locations at various depths where fissures are found.

These are extremely brittle layers and should be noted by the structural engineer. The area of fissures,

however, have the tendency to stay relatively strong while being compacted and surrounded by other

volcanic or metamorphosed rocks.

Figure 4: Fissures in Andesite.

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Table 3: Summary of depth Andesite and other softer rock types where found.

Depth (m) HRAP1 HVGS1 HVGS2 HVGS3 HVGS4

0.00 O O O O O

0.50 O O O O O O OTHER

1.00 O O O O O A ANDESITE

1.50 O O A O O

2.00 O A A O O

2.50 O A A O O

3.00 O A A A O

3.50 O A O O O

4.00 O A O O O

4.50 O A A A O

5.00 O O O A O

5.50 O A A O A

6.00 O A A O A

6.50 O A A O A

7.00 O A A O A

7.50 O A A O A

8.00 O A A A A

8.50 O A A A A

9.00 O A A A A

9.50 O A A A A

10.00 O A A A A

10.50 O A A A A

11.00 O A A A A

11.50 O O A A A

12.00 O O A A A

12.50 O A A A A

13.00 O A A A A

13.50 O A A A

14.00 O A A A

14.50 O A A A

15.00 O A A A

15.50 O A A A

16.00 O A A A

16.50 O A A A

17.00 O A A A

17.50 O A A A

18.00 O A A A

18.50 O A A A

19.00 O A A A

19.50 O A A A

20.00 O A A A

20.50 O A A

21.00 O A

21.50 O A

22.00 O A

22.50 O A

23.00 O A

23.50 O A

24.00 O A

24.50 O A

25.00 O A

25.50 O A

26.00 O A

26.50 O

27.00 O

27.50 A

28.00 A

28.50 A

29.00 A

29.50 A

30.00 A

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Shear box tests

The strength of a soil depends on its resistance to shearing stresses. It is made up of two parameters

(also known as shear strength parameters) namely;

Friction, ∅ , (friction between individual particles),

Cohesion, 𝑐, (adhesion between the soil particles).

The objective of the shear box test is to determine the shear strength parameters of the soil. The test

can be carried out on either undisturbed samples or remoulded samples. A normal load is applied to the

specimen and the specimen is sheared across a pre-determined horizontal plane between the two

halves of the shear box. Measurements of shear load, shear displacement and normal displacement are

recorded. Figure 5 a) shows the mould where the soil sample is placed and Figure 5 b) shows a section

view of a soil sample placed in the mould. Figure 5 c) shows the setup in the laboratory where the tests

were conducted.

Figure 5: a) Mould where sample is placed, b) section view of soil sample in mould and c) setup in laboratory.

(a) (b)

(c)

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Soil samples were obtained by using an auger drill from holes up to 2 m deep. Only one sample was

taken per site as it is assumed that the soil is fairly homogenous on each site. To facilitate the

remoulding purpose, a soil sample was compacted at optimum moisture content in a compaction mould

using the Proctor compaction method. The Proctor compaction test consists of compacting soil samples

at a given water content in a standard mould with standard compaction energy. The soil is then placed

and compacted in the Proctor compaction mould in three different layers where each layer received 33

blows of the standard hammer. Before placing each new layer, the surface of the previous layers is

scratched in order to ensure a uniform distribution of the compaction effects. Moisture content for the

specimens at compaction is shown in Table 4.

Table 4: Moisture content at compaction

Sample Moisture content

(𝝎) SLR 23.1 %

VGOS 19.7 %

The specimen was obtained using a 60 x 60 mm cutter. The sample was placed into the mould after

cutting, and saturated for 24 hours under the normal load to ensure that it was fully saturated and

consolidated. The rate at which the horizontal displacement occurs was set at 0.00833 mm/min. The

test run until the shear load stabilizes and has reached a maximum value. The test was repeated three

times with identical specimens under different normal loads, namely 50 kPa, 100 kPa and 200 kPa. From

the results, the shear strength parameters can be determined

The shear parameters were calculated with two different methods. Method 1 assumes the area where

shear takes place changes and Method 2 assumes that the area stays constant. Method 2 is in

accordance with the British Standards (BS1377).

When the normal stress is plotted against the maximum shear stress, as in Figure 6, the shear

parameters can be calculated. Table 5 shows the results of the tests calculated by both methods.

Table 5: Shear parameters

Sample Friction Angle, ∅

Method 1 Friction Angle, ∅

Method 2 Cohesion, 𝒄 Method 1

Cohesion, 𝒄 Method 2

SLR 34.2⁰ 30.9⁰ 16 kPa 10 kPa

VGOS 37.2⁰ 32.6⁰ 6 kPa 5 kPa

From the results above appropriate calculations can be done by the foundation engineer to ensure

stability of the planned structures. It is strongly advised to use the cohesion as 0 kPa, because it tends to

vary between samples and can be seen as a conservative approach. The different values obtained for

the friction angles are in the expected range for the soil tested.

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Figure 6: Normal Stress vs Shear Stress for different samples and methods

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Resistivity tests

The resistivity test was done at the HRAP location, and data obtained was used to correlate with the

core logging. The primary goal in this test was to identify mineral and rock types.

The electrical resistivity test is done by using electrodes placed at set intervals over a distance spread

over an area to be investigated. The length or distance of the contacts is related to the depth needed to

be characterised. Various parameters such as mineral density, ability to conduct current, water content

and pore pressure are being measured. The information obtained can be used to identify certain mineral

and earth properties such as specific rock types and soil density.

Figure 7: 2-D Field Surveyor instrument on site.

Figure 7 is the 2-D Field Surveyor instrument at the HRAP (SLR) site. Figure 7 a) shows the electrodes

being placed out over the distance and the area to be investigated. Figure 7 b) shows one of these

contacts placed into the ground and Figure 7 c) the 2-D Field Surveyor instrument.

(a)

(b)

(c)

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Resistivity tests were done at the location of the HRAP site, and data obtained where matched to

Figure 8.

Most of the data did match with that of Andesite, but because of the large overlapping in reference data

there’s a big factor of uncertainty.

The data obtained is attached at the end of this document in Appendix B.

Figure 8: Reference for the Resistivity of rocks, soils and minerals used in the classification.

The large percentage of overlapping in data makes the data obtained in this procedure a confirmation of

what was found in the physical core analysis, rather than an exact classification of a certain mineral or

rock type.

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Conclusion and recommendations

The geology of the area is stable and consists of metamorphosed and volcanic rocks. All of these are

stable bedrock layers. The Andesite is strong, but brittle in places and very deep. The metamorphosed

shale exhibit sufficient strength to be utilised as a foundation layer whilst the andesite will result in a

more costly foundation solution due to its depth. It is recommended that either wide pad foundations or

deep piles be used.

When considering direct shear tests, it is advised to use the cohesion as 0 kPa as it tends to vary

between samples and can be seen as a conservative approach. It is not certain if the cohesion measured

is true cohesion or apparent cohesion (a results from the tendency of soil to expand when sheared). The

different values obtained for the friction angles are in the expected range for the soil tested.

The resistivity tests should serve as a confirmation of the different layers found in the area. Data is

unreliable as it overlaps considerably with other rock types. The advantage of this method is that the

test could possibly indicate other rock types not found near or on the location drilled.

The structural engineer has to finally decide on which geological layer to place the final foundation and

should use this report only as a guide to his final calculations and recommendations.

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Appendix A - Core Logs

Borehole Date Logged

Depth

(m)

Length

(m)

Box

number

Mater.

Recov

(m)

Loss/GainMaterial

Recovered

R.Q.D

(0,10m)

Grain Size

Fine/Med/

Coarse

Fabric

TypeFractures Weathering Remarks Rock Name

Picture

taken/

Number

1,27 1,27 0,40 -0,87 31,50% 0,00%Very fine to

fine- -

Extremely

Weathered

Red iron oxidation. Quarts

conglomarates 10 mm - 20 mm.

Shaley mudstone

clay9971

3 1,73 0,40 -1,33 23,12% 40,00% Very fine - -Extremely

Weathered Red iron oxidation. Plant roots. Mudstone clay

4,96 1,96 1,62 -0,28 82,65% 15,43%Very fine to

fine2 Irregular

Extremely

Weathered

Red iron oxidation. Plant roots.

Quarts conglomarates < 10 mmClay mudstone

7,30 2,34 2,34 0 100,00% 6,84%Very fine to

fine- -

Extremely

Weathered

Red iron oxidation. Plant roots.

Quarts conglomarates < 10 mm.

Fluvial structures.

Clay mudstone 9974

8,22 0,92 0,67 -0,25 72,83% 0,00%Very fine to

fine- -

Extremely

Weathered

Red iron oxidation. Plant roots.

Quarts conglomarates < 10 mmClay mudstone

9,03 0,81 0,81 0 100,00% 0,00%Very fine to

fine- -

Extremely

Weathered

Red iron oxidation. Plant roots.

Quarts conglomarates < 10 mm. Clay mudstone

10,30 1,27 1,30 + 0,03 102,36% 0,00%Very fine to

fine- -

Extremely

Weathered

Red iron oxidation. Plant roots.

Quarts conglomarates < 10 mm. Clay mudstone

12,10 1,8 1,80 0 100,00% 5,56%Very fine to

fine2 Irregular

Extremely

Weathered

Red iron oxidation. Plant roots.

Quarts conglomarates < 10 mm. Clay mudstone

13,30 1,2 1,25 +0,05 104,17% 24,80%Very fine to

fine- - Weathered

Mineral oxidation. Plant roots.

Quarts conglomarates < 5 mm.

Brown / black

mudstone9975

14,50 1,2 1,20 0 100,00% 0,00%Very fine to

fine- - Weathered

Mineral oxidation. Plant roots.

Quarts conglomarates < 5 mm.

Brown / black

mudstone

15,36 0,86 0,86 0 100,00% 32,56%Very fine to

fine- - Weathered

Mineral oxidation. Plant roots.

Quarts conglomarates < 5 mm.

Brown / black

mudstone

16,30 0,94 0,94 0 100,00% 0,00%Very fine to

fine- - Weathered

Mineral oxidation. Plant roots.

Quarts conglomarates < 5 mm.

Brown / black

mudstone

18,15 1,85 1,30 -0,55 70,27% 0,00%Very fine to

fine- - Weathered

Mineral oxidation. Plant roots.

Quarts conglomarates < 5 mm.

Brown / black

mudstone

19,30 1,15 1,20 +0,05 104,35% 63,33%Very fine to

fine1 Irregular -

Mineral oxidation. Plant roots.

Quarts conglomarates < 5 mm.

Brown / black

mudstone9976

22,30 3 3,10 +0,10 103,33% 22,26%Very fine to

fine1 Irregular -

Mineral oxidation. Plant roots.

Quarts conglomarates < 5 mm.

Brown / black

mudstone

2/3

3/3

HRAP 1 Logged By Jurgens Schoeman and Susan Bothma

Fabric type and/ or observed: Massive (1) Bedded (2) Foliated (3) Cleavage (4) Schistose (5) Gneissose (6) Laminated (7) Alligned Minerals (8) Slickenside (9) Fissures (10)

01 December 2015

1/3

25,30 3 2,10 -0,90 70,00% 0,00%Very fine to

fine1 Irregular -

Arenaceous. Mineral oxidation.

Plant roots. Quarts conglomarates <

5 mm.

Brown / black

mudstone

27,72 2,42 1,24 -1,18 51,24% 8,87%Very fine to

fine1 Irregular -

Andesite contains lenticular quarts

with no definite orientation.

Massive fine

grained

mudrock/signs of

metamorphism.

Contact with

Andesitic Basalt.

9982

28,30 0,58 0,89 +0,31 153,45% 83,15% Fine 1 Irregular -

Andesite contains lenticular quarts

with no definite orientation.

Greenish minerals. Possibly chlorite.

Small quarts veins.

Andesite 9983

29,89 1,59 1,59 0 100,00% 46,54% Fine 1 Irregular -

Andesite contains lenticular quarts

with no definite orientation.

Greenish minerals. Possibly chlorite.

Small quarts veins < 1 mm thick.

Andesite

3/3

Borehole Date Logged

Depth

(m)

Length

(m)

Box

number

Mater.

Recov

(m)

Loss/

Gain

Material

Recovered

R.Q.D

(0,10m)

Grain Size

Fine/Med/Coarse

Fabric

TypeFractures Weathering Remarks Rock Name

Picture

taken/

Number

0,98 0,98 0,90 -0,08 91,84% 13,33% Very fine to fine 2 Slightly Irregular Weathered

Plant roots. White caly. Red

oxidation. Loose rock

fragments < 20 mm

Clay mudstone 9984

1,96 0,98 0,70 -0,28 71,43% 0,00% Very fine to fine 1 Irregular -

Slightly carbonate, reacts

with HCl. Contact with

Andesite. Glasy aphanitic

crystals. Irregularly spaced.

Gass bubbles in form of

fissures. Amygdaloidal

quarts/calcite crystals < 10

mm. Strongly reacts with

HCl.

Calsitic Andesite 9985

3 1,04 0,41 -0,63 39,42% 46,34% Very fine to fine 2 Irregular Slightly

Aphanitic to phaneritic

crystals of quarts and mica

minerals. Irregular crystal

orientation.

Andesite

5,02 2,02 Fine to medium 1 - -

Aphanitic to phaneritic

crystals. Quarts, calcite,

feldspar and mica minerals.

Andesite

5,17 0,15 Very fine to fine - Irregular Weathered

Very loose unstable

fragments of andesite rock

and mudstone.

Andesite / mudstone

rock9986

5,42 0,25 Fine to medium 1 - -

Aphanitic to phaneritic

crystals. Quarts, calcite,

feldspar and mica minerals.

Andesite

6,15 0,73 Fine to medium 1 - -

Aphanitic to phaneritic

crystals. Quarts, calcite,

feldspar and mica minerals.

Andesite

HVGS 1 Logged By

-0,141,86 89,42% 84,41%

Jurgens Schoeman and Susan Bothma 02 December 2015

Fabric type and/ or observed: Massive (1) Bedded (2) Foliated (3) Cleavage (4) Schistose (5) Gneissose (6) Laminated (7) Alligned Minerals (8) Slickenside (9) Fissures (10)

-0,12,32 79,74%95,87%1/3

6,30 0,15 Fine to medium 10 Reggular Slightly

Heavily fissured. Phaneritic

to aphanitic crystals of

quarts, chlorite and calcite.

Andesite / Scoria

(heavily fissured)9987

7,50 1,2 Fine to medium 1 - -

Aphanitic to phaneritic

crystals. Quarts, calcite,

feldspar and mica minerals.

Andesite

8,84 1,34 1,31 -0,03 97,76% 22,90% Fine to medium 1, 10 Reggular SlightlyVertical fractures. Phaneritic

aphanitic crystals < 10 mm.Andesite 9988

10,30 1,46 1,56 +0,1 106,85% 0,00% Fine to medium 1 Reggular SlightlyCrystals < 10 mm. Quarts.

Iron oxidation.Andesite

11,05 0,75 Fine to medium 1 Reggular Slightly

Phaneritic aphanitic

crystals. Glasy, quarts,

calcite, mica. < 10 mm

Andesite

11,25 0,2 Very fine to fine - ReggularVery

weathered

Very loose fractured

unstable sand/mudstone.

Fragments < 20 mm

sand/mudstone/Ande

site9989

12,32 1,07 Fine to medium 1 Reggular Slightly

Phaneritic aphanitic

crystals. Glasy, quarts,

calcite, mica. < 10 mm.

Loose fragments < 20 mm

Andesite

13,37 1,05 1,11 +0,05 105,71% 35,14% Fine to medium 1 Irregular -

Large quarts crystals < 60

mm. Interlayed calcite,

feldspars and chlorite.

Andesite

14,52 1,15 1,08 -0,08 93,91% 9,26% Fine 1 Irregular Weathered

Mineral oxidation. Vertical

fractures. Some fissures.

Loose fragments < 10 mm.

Large crystals < 15 mm.

Andesite

16,50 1,98 2,03 +0,03 102,53% 5,91% Fine to medium 1 Reggular Slightly

Quarts crystals < 20 mm.

Aphanitic phaneritic texture.

Amygdaloidal inplaced by

calcite and quarts.

Andesite

2/3

-0,141,86 89,42% 84,41%

+0,022,04 19,12%100,99%

1/3

18,67 2,17 2,30 +0,13 105,99% 19,57% Fine to medium 1 Reggular Slightly

Vertical fractures. Calsite,

quarts, feldspar and

chlorite. Loose fragments <

30 mm. Mineral oxidation.

Andesite

19,50 0,83 0,83 0 100,00% 12,05% Fine to medium 1 Reggular Slightly

Quarts crystals < 15 mm.

Vertical fractures. Calsite,

quarts, feldspar and

chlorite. Loose fragments <

30 mm. Mineral oxidation.

Andesite

3/3

Borehole Date Logged

Depth

(m)

Length

(m)

Box

number

Mater.

Recov

(m)

Loss/

Gain

Material

Recovered

R.Q.D

(0,10m)

Grain Size

Fine/Med/Coarse

Fabric

TypeFractures Weathering Remarks Rock Name

Picture

taken/

Number

0,75 0,75 0,61 -0,14 81,33% 0,00% Very fine to fine 2 IrregularExtremely

weathered

Red mineral oxidation. Clay

mudstone. Large loose

fragments < 30 mm. Quarts

fragments < 20 mm.

Clay 9991

1,05 0,3 Very fine to fine 2 Irregular Weathered

Clay mudstone slightly

metamorphosed with

mineral oxidation and

quarts < 10 mm. Contact

with Andesite.

Clay/ Andesite

1,7 0,65 Fine 1 - -

Calsite. Reacts strongly with

HCl. Calcite crystals < 10

mm. Other minerals: Quarts,

feldspars and chlorite

Andesite

3,00 1,3 0,25 -1,05 19,23% 0,00% Fine 1, 10 IrregularSlightly

weathered

Mineral oxidation. Large

phaneritic crystals of quarts.Andesite 9992

3,30 0,3 Very fine to fine - IrregularExtremely

weathered

Loose fragments.

Metamorphosed mudstone.

Metamorphosed

mudstone/Andesite

4,88 1,58 Very fine to fine 1, 8 Reggular -

Calsite. Reacts strongly with

HCl. Calcite crystals < 10 mm

preffered orientation

horisontal.

Andesite

5,08 0,2 Very fine to fine 2, 10 ReggularSlightly

weathered

Mudrock layer interlayed

with AndesiteMudrock/Andesite

HVGS 2 Logged By Jurgens Schoeman and Susan Bothma 02 December 2015

Fabric type and/ or observed: Massive (1) Bedded (2) Foliated (3) Cleavage (4) Schistose (5) Gneissose (6) Laminated (7) Alligned Minerals (8) Slickenside (9) Fissures (10)

99,24%0,022,61 35,63%

1/3

0,80 0,15 84,21% 37,50%

5,63 0,55 Very fine to fine 1, 10 Reggular -

Fissures. Very small < 1mm

calsite vein horisontally.

Feldspar and Quarts

crystals, no preffered

orientation.

Metamorphosed mudstone

Andesite

7,20 1,57 1,47 -0,10 93,63% 6,80% Very fine to fine 1, 10 Reggular Slightly

Heavely fractured calsite

Amygdaloidal implaced by

quarts and calsite. Aphanitic

to phaneritic crystals < 10

mm

Andesite 0012

7,99 0,79 0,66 -0,13 83,54% 0,00% Very fine to fine 1, 10 Reggular Slightly

Mineral oxidation.

Phaneritic to aphanitic

crystals. Quarts, feldspar

and calsite.

Andesite

10,29 2,3 2,28 -0,02 99,13% 70,18% Very fine to fine 1 Irreggular Slightly

Aphanitic texture with larger

calcite crystals < 10 mm.

Other minerals: Quarts and

feldspar.

Andesite

13,33 3,04 2,71 -0,33 89,14% 83,03% Very fine to fine 1 Irreggular Slightly

Aphanitic texture with larger

calcite crystals < 10 mm.

Other minerals: Quarts and

feldspar.

Andesite

14,85 1,52 1,47 -0,05 96,71% 78,23% Very fine to fine 1, 10 Irreggular Slightly

Gass bubbles in the form of

fissures. Aphanitic texture

with larger calcite crystals <

10 mm. Other minerals:

Quarts and feldspar.

Andesite

15,71 0,86 0,75 -0,11 87,21% 0,00% Very fine to fine 1 Irreggular Slightly

Heavely fractured. Aphanitic

texture with larger calcite

crystals < 10mm. Other

minerals: Quarts and

feldspar.

Andesite

16,33 0,62 0,55 -0,07 88,71% 36,36% Very fine to fine 1 Irreggular Slightly

Banded layer of calcite.

Other calcite crystals <

10mm. Other minerals:

Quarts and feldspar.

Andesite

99,24%0,022,61 35,63%

2/3

1/3

19,33 3 3,04 +0,04 101,33% 37,83% Very fine to fine 1 Irreggular WeatheredHeavely fractured. Calsite

and quarts crystals < 10mm.Andesite 0017

20,73 1,4 1,37 -0,03 97,86% 0,00% Very fine to fine 1, 10 Reggular Slightly

Vertical fractures with

calsite and quarts < 20mm

in no spesific orientation.

Andesite 0021

22,33 1,6 1,68 +0,08 105,00% 29,76% Very fine to fine 1, 10 Reggular Slightly

Vertical fractures with

calsite and quarts < 20mm

in no spesific orientation.

Andesite

24,00 1,67 1,48 -0,19 88,62% 0,00% Very fine to fine 1, 10 Reggular Slightly

Vertical fractures with

calsite and quarts < 20mm

in no spesific orientation.

Andesite

25,33 1,33 1,23 -0,1 92,48% 48,78% Very fine to fine 1, 10 Reggular Slightly

Vertical fractures with

calsite and quarts < 20mm

in no spesific orientation.

Andesite

2/3

3/3

Borehole Date Logged

Depth

(m)

Length

(m)

Box

number

Mater.

Recov

(m)

Loss/

Gain

Material

Recovered

R.Q.D

(0,10m)

Grain Size

Fine/Med/Coarse

Fabric

TypeFractures Weathering Remarks Rock Name

Picture

taken/

Number

0,85 0,85 0,80 -0,05 94,12% 0,00% Very fine to fine - -Extremely

weathered

Verry brittle, fractured

mudstone/clay/sandstone.

Loose rock fragments

5,39 0,55 Very fine to fine - ReggularSlightly

weathered

Aphanitic to phaneritic

texture with quarts, calcite

and feldspar crystals

Borehole Date Logged

Depth

(m)

Length

(m)

Box

number

Mater.

Recov

(m)

Loss/

Gain

Material

Recovered

R.Q.D

(0,10m)

Grain Size

Fine/Med/Coarse

Fabric

TypeFractures Weathering Remarks Rock Name

Picture

taken/

Number

1,23 1,23 0,50 -0,73 40,65% 0,00% Very fine to fine - Reggular WeatheredMetamorphosed mudstone

with Andesite.

Metamorphosed

mudstone/Andesite0038

2,3 1,07 0,50 -0,57 46,73% 0,00% Very fine to fine - Reggular Weathered

Loose fragments < 30mm.

Metamorphosed mudstone

with Andesite.

Metamorphosed

mudstone/Andesite

3 0,7 0,60 -0,10 85,71% 0,00% Very fine to fine - Reggular Weathered

Loose fragments < 30mm.

Metamorphosed mudstone

with Andesite.

Metamorphosed

mudstone/Andesite

5,14 2,14 1,35 -0,79 63,08% 11,11% Very fine to fine 1, 10 Reggular Weathered

Andesite contains calsite,

quarts and feldspar crystals

< 15mm.

Andesite

7,35 2,21 2,20 -0,01 99,55% 6,82% Very fine to fine 10 Reggular Weathered

Vertical fractures with

fissures. Calsite and quarts

crystals < 10mm.

Andesite

10,21 2,86 2,86 0,00 100,00% 27,97% Very fine to fine 1, 10 ReggularSlightly

weathered

Andesite contains calsite,

quarts < 10mm.Andesite

11,94 1,73 1,53 -0,20 88,44% 13,07% Very fine to fine 1, 10 ReggularSlightly

weathered

Andesite contains fissures

and calsite, quarts < 10mm.Andesite 0039

12,65 0,71 0,80 0,09 112,68% 0,00% Very fine to fine 10 Reggular Weathered

Highly fractured with

mineral oxidation and

quarts crystals

Andesite 0040

1/2

2/2

HVGS 4 Logged By Jurgens Schoeman and Susan Bothma 02 December 2015

Fabric type and/ or observed: Massive (1) Bedded (2) Foliated (3) Cleavage (4) Schistose (5) Gneissose (6) Laminated (7) Alligned Minerals (8) Slickenside (9) Fissures (10)

25 | P a g e

Appendix B - Resistivity tests Data

26 | P a g e

Full spacing

27 | P a g e

Half spacing