Cape Geophysics - Breedezicht Estate, Witsand … Securing of casing segments Air jetting of...

Cape Geophysics 9 Disa Street

CK 2007/094489/23 Hermanus (South Africa)

7200

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Cell: +27(0)823250747

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Drilling report (Final) (17/06/2009 – 10/07/2009)

Breedezicht

Witsand

July 2009

Prepared by:

M de Klerk

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Client: Wilcoprop 202 (PTY) Ltd P.O. Box 754 Auckland Park 2006

Drilling contractor: Smith Drilling INC.. P.O. Box 242 Montaqu 6720

VAT Registration no: 487203231 Tel/fax: 023-614 3651 Summary. A total of five boreholes (BZ 001 – BZ 005) were drilled on the Breedezicht estate during the period 17

th June – 10

th July 2009. Total drilling cost including construction = R 225820.00 excl.

VAT. Total airlift yield on boreholes BZ 001, BZ 003 and BZ 004 = 12190 litres/hour. Total meters drilled = 518m.

Drilling diameter of all boreholes = 196mm.

PVC casing diameter = 140mm (class 12).

Gravel size = 6mm.

Screen size = 1.0mm (PVC class 12).

Steel casing diameter = 196mm. The locality map below shows the borehole positions and allocated borehole numbers. Detailed logs of the drilled boreholes are listed below the locality map. Chemical analyses of the groundwater are listed in Appendix A. 1. Results. BZ 001. Drilling was initially halted on this first borehole due to the salinity of the groundwater. It was later deepened to 76 meters and constructed with 76 meters of 140mm, class 12 PVC casing, screens and end cap. Final airlift yield is 7810 litres/hour. Recommended pump depth = 75m. BZ 002. The borehole was initially drilled to a depth of 100m. Groundwater yield at that depth was 790 litres/hour. Deeper drilling to 226 meters, to intersect sandstone layers in the shale formation, was unsuccessful and the yield increased to 2250 litres/hour at a depth of 123 meters. Due to collapsing of the near surface formation, 30 meters of 196mm steel casing had to be installed. Due to the drilling rig capability, drilling was halted at 226 meters. Due to the low depth/yield ratio, this borehole was not cased with PVC. The steel casing was not retrieved and the borehole was sealed for possible future use.

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BZ 003. The borehole was back-filled with 6mm gravel from 88 – 71meters and constructed with 71 meters of 140mm class 12 PVC casing, screens and end cap. Final airlift yield = 2770 litres/hour. Recommended pumping depth = 70 meters. BZ 004. The borehole was back-filled with 6mm gravel from 70 – 60 meters and constructed with 60 meters of 140mm class 12 PVC casing, screens and end cap. Final airlift yield = 1620 litres/hour. Recommended pumping depth = 59 meters. BZ 005. This borehole can be considered dry and the final blow yield of approximately 400 litres/hour does not justify construction. The borehole casing (steel) was removed and the hole, back filled with drilling chips. 2. Borehole construction & development. Each class 12 PVC casing and screen segment were clued and secured with 8 rivets and or stainless steel screws. The rivets or screws do not protrude trough the PVC casing. The PVC casing (lining) of each constructed borehole rest on 6mm gravel. The PVC screens were slotted with 1mm slots and the screens were installed in the bottom section of the boreholes (see Appendix A). An end cap was riveted at the bottom of the PVC screen. The annulus between the 140mm PVC casing/screens and the 196mm borehole were carefully filled with 6mm gravel to the surface. 30 – 60 minutes of air jetting (per borehole) was done with a 2m steel nozzle to ensure a continuous and clean gravel pack around the PVC casing. Concrete slabs were finally casted around the boreholes and closed with PVC caps. PVC Screens (140mm OD, 1.0mm slots)

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Securing of casing segments

Air jetting of constructed boreholes

3. Safe abstraction volume.

The safe abstraction volume from a borehole (normally required by the Dept. Water Affairs) can only be established with scientific evaluation of the groundwater drawdown and recovery rates through pump testing. A 48 hour constant discharge test is recommended on borehole BZ 001 and a 24 hour test on boreholes BZ 003 and BZ 004. Maximum estimated cost for test pumping of the three boreholes = R 31 000.00 excl VAT (Pumpcor Riversdale) excluding data analysis and pump-test supervision (optional). 4. Desalination. Desalination/treatment will produce 65% potable water of the total safe abstraction groundwater volume. Cost of a 12 000l/hour treatment plant will be approximately R785 000.00 (Appendix B). Note that this treatment plant will produce 12 000 litre/hour potable water. Pre treatment water storage would be necessary as the minimum input water volume is 18 000 litres/hour. Awaiting running cost prediction of treatment plant from Grahamtek (Somerset West).

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5. Recommendations & Considerations. 5.1. Pilot deeper drilling (+- 300-400m) on borehole BZ 002? Awaiting quotation from RPM Drilling, Worcester. 5.2. Deep geophysics (50-1000m)? GEC consulting Pretoria. Cost estimate = R 25000.00 5.3. Additional shallow boreholes? 5.4. Individual rainwater storage tanks at properties. 5.5. Indigenous gardening with minimum lawn.

Locality map with borehole positions.

*************************************************************************** M de Klerk (Geophysicist)

July 2009.

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APPENDIX A. (Borehole logs and construction)

BOREHOLE LOG: HYDROGEOLOGICAL AND CONSTRUCTION

Borehole No: BZ-001

Area/Town: Witsand

Province: Western Cape

Project / Client: Breedezicht

Logged by: M de Klerk

Date completed: 09/07/2009

Map ref.: 3420 BD

Coordinate (WGS 84): 34,39757 S

20,81953 E

Airlift yield (final): 2.17 l/s (7810 l/h)

Water level: 22.9 (18/06/2009)

Collar height: NA

Altitude: NA

Geophysical peg no: Profile Wit-1/450m

Borehole diameter (mm or inch) Water strikes: 1 2 3 4 5 6 7

Dia: 10” Dia: 8” Dia: ______ Dia: ______ Depth: 29 38 49 63/64 70

From To From To From To From To Cum yield (l/s): 0.1 1.38 1.78 1.98 2.17

0 6m 6m 76 Strike yield (l/s) 0.1 1.37 0.4 0.2 0.2

Plain casing diameter (mm or inch) Perforated PVC casing diameter (mm or inch)

Dia: 8” Dia: 140mm Dia: Dia: Dia: 140mm Dia: Dia: Dia:

From To From To From To From To From To From To From To From To

0 6m 0 36 36 42

42 54 54 72

Sanitary seal: from: NA to: Gravel pack (6mm): from: 0m to: 72m. Back fill from 72 to 76m

Geology: (Lithology: Color; Grain size; Weathering; Secondary features)

From(m) To(m) Description

0 1 Calcrete pebbles & highly weathered shale, soft (yellow brown)

1 5 Shale. Highly weathered, soft, light brown – light grey

5 6 Shale. Weathered, soft, light grey

6 15 Shale. Highly weathered, soft, brown-grey. Occasional quartz

15 17 Shale. Weathered, soft, light brown – grey black

17 20 Shale. Weathered to highly weathered, soft, brown - grey

20 62 Shale. Medium hard to hard, grey black. Pyrite rich from 42-50m

Quartz rich at 29m, +- 0.1 l/s (first water strike) Fractured and slightly weathered at 38 – 39m, water strike 1.37l/s (EC = 1480mS/m) Fractured and slightly weathered at 48 – 49m, water strike 0.40l/s (EC above 2000mS/m)

62 63 Shale. Grey black, Hard. Quartz rich. Water strike = 0.2l/s

63 76 Shale. Medium hard to hard. Grey black. Quartz rich (chunky) at 70m. Water strike = 0.2l/s

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Borehole No: BZ-002

Area/Town: Witsand





Map ref.: 3420 BD


20, 81782 E


Water level: NA

Collar height: NA

Altitude: NA



Dia: 10” Dia: 8” Dia: ______ Dia: ______ Depth: 29 35 55 123

From To From To From To From To Cum yield (l/s):

0.22 0.625

0 30m 6m 100 Strike yield (l/s) 0.01 0.01 0.2 0.40


Dia: 8” Dia: Dia: Dia: Dia: Dia: Dia: Dia:


0 30m

Sanitary seal: from: NA to: Gravel pack: from: NA to:



0 3 Shale. Highly weathered, light brown - brown. Occasional quartz.

3 6 Shale. Highly weathered, soft, brown – grey

6 22 Shale. Weathered shale, medium soft, light brown – dark grey. Quartz rich at 8m.

Highly weathered horizons at 12 – 13m ; 14 – 15m ; 20 – 21m

22 226 Shale. Dark black grey, fresh, medium soft to hard, fine grained.

Quartz rich at 24 – 25m; 52 – 53m; 55 – 56m; 58 – 59m; 70 – 71m; 73 – 74m; 81 – 84m; 94 – 99m; 118-120;122-125. Pyrite rich at 76m; 118-120m; 122-123m. Fractured at 95 – 96m (no oxidation)

First water strike at 29m (+- 0.1 l/s). Second water strike at 35m (+- 0.1l/s) Third water strike at 55m (+- 0.2l/s). Fourth water strike at 123m(0.23l/s) Quality: EC = 1645 mS/m measured at 55m. 0, 22 l/s (black water slurry).

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Borehole No: BZ-003

Area/Town: Witsand





Map ref.: 3420 BD


20, 82029 E

Airlift yield (final): 0.77/s (2770 l/h)

Water level: 31.9 m

Collar height: NA

Altitude: +- 37m



Dia: 10” Dia: 8” Dia: ______ Dia: ______ Depth: 46 59 75 82 83/85

From To From To From To From To Cum yield (l/s): 0.01

0.55

0.68 0.74 0.77

0 6m 6m 88m Strike yield (l/s) 0.01 0.54 0.13 0.06 0.03


Dia: 8” Dia: Dia: Dia: Dia:140mm Dia: Dia: Dia:


0 6m 0 53 53 71

Sanitary seal: from: NA to: Gravel pack(6mm): from: 0m to: 71m. Back fill from 71 to 88m



0 1 Soil & ferricrete.

1 2 Shale. Highly weathered, soft, yellow brown, quartz rich

2 19 Shale. Highly weathered, medium soft, light brown – brown.

19 24 Shale. Weathered, light brown-brown and light grey, soft, quartz rich

24 27 Shale. Highly weathered, light brown – brown, soft

27 28 Shale. Weathered, light brown – grey

28 38 Shale. Grey black, soft. Quartz rich at 34m

38 70 Shale. Grey black, medium hard. Quartz rich at 40m, 45 – 46m, 59 – 61m, 67m.

70 88 Shale. Grey black, hard. Quartz rich at 72m, 75 - 76m, 79 – 85m. Quartz chunks at 85m

Water quality: EC above 2000 mS/m measured at 59m.

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Borehole No: BZ-004

Area/Town: Witsand





Map ref.: 3420 BD


20,82058 E


Water level: 32.2 (24/06/2009)

Collar height: NA

Altitude: NA



Dia: 10” Dia: 8” Dia: ______ Dia: ______ Depth: 35 40/44 50/52

From To From To From To From To Cum yield (l/s): 0.1 0.25 0.45

0 6m 6m 70 Strike yield (l/s) 0.1 0.15 0.2


Dia: 8” Dia: 140mm Dia: Dia: Dia: 140mm Dia: Dia: Dia:


0 6m 0 48 48 60

Sanitary seal: from: NA to: Gravel pack (6mm): from: 0m to: 60m. Back fill from 60 to 70m



0 1 Boulders and top soil, quartz rich.

1 16 Shale. Highly weathered, soft, yellow brown. Quartz rich at 9m.

16 35 Shale. Weathered, soft, brown – grey. Occasional quartz from 16-32m.

35 56 Shale. Medium-hard, grey black. Quartz rich at 37 – 38m, 40 – 52m.

56 70 Shale. Hard, grey black. Quartz rich at 61 – 64m.

Water quality: EC above 2000 mS/m measured at 52m.

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Borehole No: BZ-005

Area/Town: Witsand





Map ref.: 3420 BD


20,81486 E

Airlift yield (final): Not measured (+- 0.1l/s, 360l/h)

Water level: Not measured

Collar height: NA

Altitude: NA



Dia: 10” Dia: 8” Dia: ______ Dia: ______ Depth: 35

From To From To From To From To Cum yield (l/s): 0.1

0 6m 6m 58 Strike yield (l/s) 0.1

Plain casing diameter (mm or inch) Perforated casing diameter (mm or inch)

Dia: 8” Dia: Dia: Dia: Dia: Dia: Dia: Dia:


0 6m

Sanitary seal: from: NA to: Gravel pack: from: NA to:



0 2 Shale. Highly weathered, yellow brown, quartz rich.

1 9 Shale. Highly weathered, soft, yellow brown - grey. Quartz rich at 3 - 5m.

9 10 Shale. Weathered, soft, light grey – black, quartz rich.

10 13 Shale. Highly weathered, soft, yellow brown - grey

13 14 Shale. Weathered, soft, light grey – black, quartz rich.

14 18 Shale. Weathered to highly weathered, soft, brown-grey.

18 21 Shale. Grey-black, soft.

21 22 Quartz rich zone slightly oxidized.

22 26 Shale. Black, medium-hard.

26 27 Shale. Weathered, soft, brown.

27 58 Shale. Fresh, dark grey-black, medium – hard. Quartz rich fracture at 42-44m (Dry!)

NOTE: 8’’ x 6m casing removed and borehole backfilled with drill cuttings.

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APPENDIX B. (Chemistry results)

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APPENDIX C. (Desalination)

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