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D’AGUILAR GOLD LIMITED

EPM 15310

ELGINVALE NORTH

RELINQUISHMENT REPORT TO JANUARY 9 2008

NEIL WILKINS M.Sc.

SUMMARY

EPM 15310 covers 80 sub blocks 30 kilometres southwest of Kilkivan in southern Qld. D’Aguilar Gold has had the tenement for 2 years and now wishes to relinquish 40 sub- blocks, effective 9th January 2008.

There are no historic workings within the EPM, however the Peenam and Elginvale porphyry copper and or gold occurrences are nearby. No previous work has been conducted apart from minor stream sediment sampling on the margins.

The prospect was selected because it lies on the Mt Perry – Mt Rawdon fault system which hosts a number of large porphyry gold and copper occurrences. Additionally silicieous epithermal float was noted on the roadsides just west of Peenam.

In the year 2006, work consisted of basic geochemical sampling –mainly stream sediments and soils, with a few minor rocks. A basic geological interpretation and a synthesis with regional features has been attempted.

This interpretation proposes that there is one or two shallowly buried copper gold porphyry systems within the EPM, extending from the site of previous drilling on the Peenam prospect in EPM 13361. The eastern porphyry is unusual for southeast Queensland in that it has a high gold to copper ratio, no molybdenum, and a magnetite bornite chalcopyrite association. The western porphyry is exposed at a slightly higher level, and its nature is unclear.

During the 2007, D’Aguilar flew a detailed airborne EM and magnetics survey, which showed major structures, some alteration and minor surfical disseminated mineralisation.

Contents

Summary

1.0 Introduction

2.0 Location and Tenure

3.0 Summary of Previous Work

4.0 Work Conducted By D’Aguilar Gold, 20064.1 Stream sediment sampling4.2 Soil and Rock Sampling4.3 Synthesis and Interpretation

5.0 Work Conducted By D’Aguilar Gold, 20075.1 VTEM Survey

6.0 Relinquished Sub-blocks

7.0 Environmental Issues

Figure 1 -Location and InfrastructureFigure 2- Stream Sediment Sampling - Anomalies Figure 3 -Soil Sampling Status Jan 07Figure 4 -Kilkivan Quartz Monzonites Figure 5 -Peenam Porphyry Cu Au OutcropFigure 6 -Peenam Porphyry – Epithermal Transition Vein Figure 7 -Geochemical Zoning Elginvale - PeenamFigure 8 -Proposed VTEM – detailed magnetics survey Figure 9 – Elginvale VTEM (Magnetics)Figure 10 – Elginvale VTEM (EM)Figure 11 - Relinquished sub-blocks (red crosses)Figure 12 - Relinquished sub-blocks (red crosses) with respect to stream sediment sample locations.

Appendix 1 - Stream Sediment Data Appendix 2 - VTEM Survey Full Report

1.0 INTRODUCTION

This report is mainly concerned with relinquishment of 40 sub-blocks within EPM 15310 but provides a summarised background regarding the tenure, location, and the previous work.

2.0 LOCATION AND TENURE

EPM 15310 covers 80 sub blocks and was granted on January 10 2006 exclusive of native title, and is held 100% by D’Aguilar Gold. The company now wishes to relinquish 40 sub-blocks.

D’Aguilar EPMs 13361 14373 and 14375 are adjacent.

The project is located some 30 kilometres south west of Kilkivan in Southern Queensland. Access is via the Goomeri – Elginvale road.

Figure 1 – Location of EPM 15310

3.0 SUMMARY OF PREVIOUS WORK

There are no known areas of old time or recent prospecting activity within the EPM itself.

Old time diggers discovered the Elginvale goldfield 15 km to the south in the 1860s and worked the eluvials and higher grade oxides to a maximum depth of 15 metres until the 1980s. The mineralisation is of a large tonnage low grade porphyry style with two phases – arsenic associated low grade dissemination and a rarer high grade veinlet phase associated with bismuth.

More recently BHP stream sediment sampling identified the Peenam gold anomalous area within a zone of chalcedonic and sugary quartz development. Subsequent D’Aguilar work recognised some outcropping biotite magnetite altered porphyry with copper. This dyke is only present in the topographically lowest sites below the silica veining. When drilled it returned a bulk grade of some 60m @ 0.25 Au and 0.22% Cu. The copper is present as chalcopyrite – bornite – magnetite.

Prior to applying for this EPM I noted epithermal silica floaters along the sides of the public road near the entrance to Peenam. It was felt that the Elginvale or Peenam systems may well pass into this EPM but would be buried under this silica caprock.

4.0 D’AGUILAR GOLD WORK COMPLETED, 2006

As there has been no previous exploration, the work has been very much a first pass program with coverage of multi element geochemistry and the use of geophysical imagery in an attempt to understand the results.

4.1 Stream Sediment Sampling

A total of 96 stream sediment samples have been taken throughout the EPM, with a higher density in the Peenam area.

The samples were 500 grams and where possible were sieved to – 4 mm. In many creeks the sediment was a reconstituted black soil that was impossible to sieve. ALS performed a ZARG ( ST44 ) digest for gold and a MS – ICP finish for a suite of gold pathfinder elements.

Zones of low to moderate copper and gold anomalism were defined, within a much more extensive basemetal – arsenic aureole. A noteworthy small stream at Baalgammon returned 2500 ppb Au from unsieved reconstituted black soil sediment. It is not known if this result is representative.

Figure 2 – Stream Sediment Gold Anomalies

4.2 Soil Sampling

A total of 212 soil samples have been taken over a 15 sq km area that embraces the central copper and gold stream sediment anomalies. The purpose was to cover all the area of interest rather than to define a drill target. As time progressed new geochemistry revealed that much of this sampling lay between two separate geochemical targets.

The samples were taken on 200m centres on traverses that were nominally 400m apart, using a GPS as a locator. The samples were 500 grams in size and were assayed by ALS using a multi element MS 43i digestion and analysis.

Figure 3

Figure 4 - Kilkivan Quartz Monzonites

4.3 Geological Synthesis

Using data from adjacent EPMs held by Daguilar, and geophysical imagery, it has been possible to interpret the results in a large scale geological context.

The mineralised porphyry dyke at Peenam is exposed at that location because it is the most incised drainage locally. Most of the surrounding prospect is exposed at a slightly higher level characterised by saccharoidal quartz and chalcedony – interpreted to be the silica rich cap to the sulphide system. There is also a flat lying conglomeratic sequence in the Neara volcanics – this also obscures the mineralisation here and at several other locations.

The quartz monzonite porphyry is the most evolved rock type in this mainly basic to shoshonitic district, and is spatially related to various forms of mineralisation as well as rhyolitic areas within the volcanics. The porphyry distribution is controlled by regional structures (Figure 4).

Figure 5 – Mineralised Quartz Monzonite Porphyry

Figure 6 - Transitional Veins Epithermal to Porphyry

Along the broad NNW trending Perry – Mt Rawdon fault system, a broad zonation is recognisable. The As Bi Au association at Elginvale appears continuous with the aureole to the Peenam Cu Au and this aureole appears almost continuous with the As Bi Au association at King Creek to the North. This large scale zonation is typical of very large porphyry copper systems – even when there are several porphyry centres.

In a slightly lower scale, there appears to be two separate porphyry centres, on the eastern and western sides of the main fault. Erosion has begun exposing the top of the high temperature phases to the east of the main fault at Peenam, but the larger western system is mainly quartz flooded lithocap. At the time of writing there has only been limited geological work, and therefore no further detail.

The geophysical imagery also shows magnetic anomalies that might represent shallowly buried magnetite bornite ores, but the line spacing and direction would mean that the apparent orientation and distribution of these anomalies are imprecise. Additionally, many of these magnetic anomalies near the base of the Neara volcanics are related to ultrabasic intrusives and olivine rich pyroclastics, representing the first phase of Triassic magmatism.

Figure 7- Geochemical Zoning Elginvale - Peenam

5.0 D’AGUILAR GOLD WORK COMPLETED, 2007

5.1 VTEM Survey

An airborne VTEM and magnetic survey was carried out during 2007. It was hoped the survey would locate magnetite chalcopyrite bornite targets beneath the caprocks.

Results showed major structures, some alteration and some minor surficial dissemination of sulphide. Overall the results were less exciting than expected.

The survey was flown in April 2007. The full written report can be found in Appendix 2.

Figure 8 - Proposed VTEM

Figure 9 – Elginvale VTEM (Magnetics)

Figure 10 – Elginvale VTEM (EM)

6.0 RELINQUISHED SUB-BLOCKS

Forty sub-blocks from the original 80 are nominated for relinquishment effective 8/1/08.

BRIS 1969 E, K, P, U, ZBRIS 1970 A, B, C, D, F, G, H, J, L, M, N, O, Q, R, S, T, U, V, W, X,

YBRIS 1971 Q, R, S, XBRIS 2115 G, H, L, M, N, Q, R, S, W, X

Figure 11 - Relinquished sub-blocks (red crosses)

The only field work associated with the relinquished areas of the EPM were stream sediment samples. (Fig 12, Appendix 1)

Figure 12 - Relinquished sub-blocks (red crosses) with respect to stream sediment sample locations.

7.0 ENVIRONMENTAL ISSUES

No environmental issues are outstanding on the relinquished portion of the EPM. No drilling, costeans or earthworks were carried out.

APPENDIX 1

STREAM SEDIMENT SAMPLE RESULTS

SampleMGAEast

MGANorth

Au ppm 1

Au method 1

Ag ppm

As ppm

Bi ppm

Co ppm

Cu ppm

Hg ppm

Mo ppm

Ni ppm

Pb ppm S %

Sb ppm

Zn ppm

SS0293 416033 7089390 0.0011 Au-ST44 0.2 2 19 37 -1 -1 14 13 -0 3 63SS0294 415724 7090433 0.0008 Au-ST44 -0.2 -2 33 34 -1 -1 59 14 -0 2 48SS0295 414940 7090170 0.0009 Au-ST44 0.2 2 26 36 -1 -1 89 16 -0 3 62SS0296 414112 7090651 0.0003 Au-ST44 0.2 -2 17 25 -1 -1 39 10 -0 -2 55SS0297 413686 7089407 0.0003 Au-ST44 0.3 -2 47 28 -1 -1 16 18 -0 -2 63SS0298 420227 7087537 0.0004 Au-ST44 0.2 3 24 34 -1 -1 99 18 -0 2 71SS0299 420428 7087424 0.0006 Au-ST44 -0.2 -2 16 17 -1 -1 67 11 -0 2 46SS0300 412624 7091265 0.0003 Au-ST44 -0.2 2 18 15 -1 -1 26 10 -0 3 38SS0567 422110 7081625 0.0139 Au-ST44 0.3 2 17 33 -1 1 12 15 0.01 2 64SS0574 413794 7092400 0.0004 Au-ST44 0.4 2 30 25 -1 1 13 14 -0 2 55SS0716 419277 7075198 0.0006 Au-ST44 0.01 30 0.08 29 41.7 0.07 0.61 14.2 11.2 0.04 0.75 67SS0717 419181 7075285 0.0001 Au-ST44 0.01 27 0.08 31.4 68.1 0.01 0.6 11.9 18 0.01 0.63 75SS0718 419519 7077104 0.0002 Au-ST44 0.05 18.2 0.07 19.6 96.5 0.03 0.44 11 13.8 0.01 0.38 76SS0719 419650 7077072 0.0005 Au-ST44 0.02 29.9 0.06 24.2 64 0.01 0.77 12.2 17.1 -0 0.69 86SS0720 419336 7077908 0.0003 Au-ST44 0.04 30.4 0.06 30.2 135 0.01 0.8 12 17.2 -0 0.99 84SS0721 418467 7079222 0.0002 Au-ST44 0.04 27.2 0.08 34.6 62.2 0.03 0.79 13.1 13.7 -0 0.44 83SS0722 418437 7079264 0.0003 Au-ST44 0.02 83.9 0.09 37.1 61.5 0.02 0.98 14.3 17.3 0.03 0.42 75SS0723 418037 7080344 0.0002 Au-ST44 0.02 24.1 0.1 41.6 61.6 0.01 0.89 24.6 23.1 0.01 0.75 73SS0724 418720 7081797 0.0001 Au-ST44 0.02 44 0.11 46.1 46 0.04 0.91 19 24.7 0.06 0.6 54SS0725 417711 7083485 0.0004 Au-ST44 0.01 22.7 0.11 35.9 94.4 0.02 0.76 17.1 33.2 -0 0.61 71SS0726 416629 7084070 0.0004 Au-ST44 0.02 44.7 0.11 49.6 71.3 0.01 1.06 15.2 33.6 -0 1.05 69SS0727 416465 7084309 0.0001 Au-ST44 0.01 26.5 0.17 51.6 66.8 0.01 0.86 18.7 29.4 -0 0.85 66SS0728 414641 7084279 0.0002 Au-ST44 -0.01 9.6 0.11 38 26.5 0.01 0.58 18.6 20.5 -0 0.41 58SS0729 416479 7083200 0.001 Au-ST44 0.02 21.4 0.11 23.2 61.4 0.02 0.33 13.7 13.8 0.06 0.36 63SS0730 415664 7082397 0.0003 Au-ST44 -0.01 13.1 0.1 43.3 28.9 0.01 0.28 22.8 16.9 -0 0.37 54SS0731 415572 7082252 0.0003 Au-ST44 0.01 14.8 0.13 31.3 24.5 -0.01 0.35 18.5 18 -0 0.52 47SS0732 415813 7081956 0.0003 Au-ST44 0.05 9.4 0.09 29.2 28.8 0.02 0.25 16.2 14 -0 0.27 62SS0733 415910 7081681 0.0007 Au-ST44 0.01 22.7 0.14 40.1 28.4 0.01 0.4 19.7 22.3 -0 0.64 50SS0734 416128 7081572 0.0005 Au-ST44 -0.01 5.7 0.1 29 28.7 0.02 0.33 15.2 14.1 -0 0.34 78SS0735 416084 7081434 0.0004 Au-ST44 0.02 7.8 0.1 20.6 27.1 0.02 0.34 12.7 12.8 0.03 0.36 73SS0736 416913 7081624 0.0004 Au-ST44 0.02 44.5 0.14 30.5 85.1 0.04 0.63 15.1 19.4 -0 0.58 79SS0737 416840 7081565 0.0003 Au-ST44 0.01 10.6 0.1 28.3 36.1 -0.01 0.57 15.1 15 -0 0.52 68SS0738 416900 7082032 0.0003 Au-ST44 0.02 29.8 0.13 22.7 82.3 0.03 0.48 12.8 16.6 0.01 0.46 84SS0739 416837 7082232 0.0004 Au-ST44 -0.01 53.9 0.09 37.2 93.3 0.01 1.22 16.4 24 -0 0.61 78SS0740 416825 7082558 0.0004 Au-ST44 0.01 27.5 0.1 32.3 97 0.01 0.62 12.1 19.4 0.01 0.49 80SS0741 416698 7088108 0.0013 Au-ST44 0.01 14.3 0.42 24.7 47.6 0.01 0.8 14.8 16.7 -0 0.64 75SS0742 417155 7087732 0.0003 Au-ST44 0.01 6 0.12 32.6 30.4 0.01 0.3 15.6 13 -0 0.29 66SS0743 417418 7087446 0.0006 Au-ST44 0.01 14.8 0.16 22.9 59.9 0.01 0.6 17.5 12.1 -0 0.43 80

SS0744 417604 7087255 0.0008 Au-ST44 0.01 14.6 0.09 31.5 64 0.05 0.51 20.2 14 -0 0.36 65SS0745 417881 7086588 0.0005 Au-ST44 0.01 9.6 0.15 34.4 32.5 0.04 0.41 19.5 18.3 -0 0.35 63SS0746 418114 7086017 0.0013 Au-ST44 0.01 14.5 0.2 25.8 47.9 0.08 0.68 14.6 14.9 -0 0.49 71SS0747 418230 7085947 0.0005 Au-ST44 0.01 12.6 0.08 33.4 65.9 0.03 0.31 23.7 9.3 0.05 0.33 75SS0748 418687 7084828 0.0003 Au-ST44 -0.01 28.6 0.29 16.1 35.7 0.02 0.42 11 9.8 0.15 0.39 66SS0749 418773 7084490 0.0001 Au-ST44 0.03 4.5 0.1 16.8 25.5 0.11 0.4 14 9.8 0.09 0.58 79SS0750 419215 7084040 0.0001 Au-ST44 0.02 23.6 0.07 18.7 37.3 0.04 0.4 10.9 9.3 0.11 0.35 74SS0751 414376 7086544 0.0001 Au-ST44 0.02 7.7 0.13 31.4 32.9 -0.01 0.26 12.5 17.9 -0 0.35 55SS0752 417892 7075121 0.0003 Au-ST44 -0.01 17.8 0.09 29.1 49.1 0.06 0.56 15.5 14.2 0.06 1.37 67SS0753 412550 7081380 0.0002 Au-ST44 0.07 15.8 0.07 33.3 33.9 0.02 0.47 14.2 10.2 0.03 0.61 58SS0754 414979 7080995 0.0006 Au-ST44 0.07 18.7 0.1 25.8 32.7 0.02 0.45 22.4 12.1 0.01 0.68 62SS0755 414961 7080980 0.0002 Au-ST44 0.04 19.2 0.08 38.5 38.2 0.02 0.53 15.9 16.3 0.02 0.63 66SS0756 414816 7080983 0.0003 Au-ST44 0.11 8.1 0.08 20 28.6 0.02 0.36 8.6 12 0.06 0.74 61SS0757 414735 7081121 0.0003 Au-ST44 0.14 10.3 0.09 22.9 29.7 0.02 0.16 12.7 10.5 0.02 0.36 66SS0758 416923 7077964 0.0004 Au-ST44 0.11 45.4 0.11 26.5 64.6 0.03 0.52 12.1 17.7 0.01 0.86 64SS0759 416928 7077930 0.0003 Au-ST44 0.07 19.9 0.12 22.5 44.4 0.03 0.36 10.1 13.8 0.05 0.62 48SS0760 417740 7078152 0.0005 Au-ST44 0.07 13.2 0.07 19.3 76.5 0.01 0.36 8.2 14.7 0.03 0.74 62SS0761 417738 7077151 0.0005 Au-ST44 0.07 16.5 0.07 30.2 94.2 0.01 0.66 10.1 22.3 0.03 0.62 67SS0762 418403 7076324 0.0002 Au-ST44 0.05 20.7 0.06 26.5 82.5 0.02 0.85 10.7 18.9 0.02 0.83 77SS0763 420702 7075863 0.0001 Au-ST44 0.08 5.4 0.06 15.6 41.5 0.02 0.3 6.9 10.6 0.04 0.69 61SS0764 421061 7076060 0.0002 Au-ST44 0.08 4.4 0.08 17.9 15.9 0.03 0.28 4.7 11 0.05 0.76 77SS0765 412769 7088301 0.0049 Au-ST44 0.2 2 41 26 -1 -1 15 19 0.02 3 60SS0766 413624 7086894 0.001 Au-ST44 0.2 2 28 23 -1 -1 11 16 0.02 -2 54SS0767 417280 7089113 0.0027 Au-ST44 -0.2 -2 6 6 -1 -1 16 5 0.02 -2 16SS0768 417910 7088636 0.0005 Au-ST44 -0.2 -2 17 35 -1 -1 65 14 0.07 -2 70SS0769 418562 7088748 0.0027 Au-ST44 0.2 2 19 30 -1 -1 83 11 0.07 3 77SS0770 418945 7089422 0.001 Au-ST44 0.3 2 31 11 -1 -1 4 21 0.08 2 38SS0771 419693 7089592 0.0004 Au-ST44 0.3 2 29 19 -1 -1 6 22 0.03 -2 52SS0772 419704 7089655 0.0002 Au-ST44 0.2 -2 30 10 -1 1 4 27 0.04 2 38SS0773 418968 7090289 0.0002 Au-ST44 -0.2 -2 9 10 -1 -1 3 13 0.04 2 40SS0774 418111 7090325 0.0013 Au-ST44 0.6 3 61 34 1 1 25 29 0.02 3 51SS0775 417531 7089917 0.0002 Au-ST44 0.3 2 27 48 -1 1 10 14 0.13 -2 252SS0776 417264 7089633 0.0004 Au-ST44 -0.2 3 25 29 -1 -1 14 12 0.02 3 67SS0777 422145 7079170 0.25 Au-OG44 0.3 2 24 42 -1 -1 12 16 0.08 4 93SS0778 422072 7079160 0.0053 Au-ST44 0.3 -2 16 32 1 -1 10 11 0.07 3 72SS0779 422835 7078683 0.0006 Au-ST44 -0.2 -2 24 11 -1 -1 5 18 0.03 5 57SS0780 421818 7078266 0.0001 Au-ST44 -0.2 -2 19 45 -1 -1 12 7 0.16 -2 101SS0781 421771 7078161 0.0002 Au-ST44 0.2 2 28 47 1 -1 14 8 0.08 -2 61SS0782 421213 7078821 0.0005 Au-ST44 -0.2 2 32 54 -1 -1 20 8 0.04 -2 61SS0783 421318 7078739 0.0002 Au-ST44 0.2 -2 26 21 -1 -1 8 19 0.03 2 58

SS0784 419776 7078262 0.0001 Au-ST44 0.3 2 24 35 -1 1 7 11 0.05 2 62SS0785 419976 7078977 0.0001 Au-ST44 0.2 -2 22 15 -1 1 5 13 0.05 2 62SS0786 419651 7079113 0.0004 Au-ST44 0.3 2 36 57 -1 -1 16 13 0.03 4 64SS0787 419571 7079048 0.0002 Au-ST44 0.3 -2 26 124 -1 1 10 19 0.02 -2 68SS0788 420000 7079451 0.0001 Au-ST44 0.2 2 25 23 -1 -1 10 10 0.04 -2 59SS0789 420168 7079385 -0.0001 Au-ST44 0.2 -2 32 27 -1 -1 11 12 0.04 -2 58SS0790 419251 7079824 0.0002 Au-ST44 -0.2 -2 21 30 -1 -1 14 12 -0 -2 61SS0791 419355 7079820 0.0001 Au-ST44 0.3 -2 26 57 -1 -1 13 13 0.02 -2 60SS0792 419523 7080244 0.0007 Au-ST44 -0.2 -2 21 36 -1 -1 15 13 -0 2 54SS0793 419490 7080255 0.0004 Au-ST44 -0.2 -2 15 50 -1 -1 11 9 -0 2 65SS0794 418314 7081721 0.0002 Au-ST44 0.3 3 30 31 1 -1 12 17 -0 -2 66SS0795 418247 7080516 0.0007 Au-ST44 0.3 -2 22 52 -1 1 10 26 -0 4 51SS0798 420069 7082142 0.0004 Au-ST44 0.2 -2 14 35 -1 -1 12 10 -0 -2 65SS0799 420206 7082594 0.0004 Au-ST44 0.3 -2 15 23 -1 1 9 8 0.17 -2 56SS0800 416100 7089338 0.0028 Au-ST44 0.2 3 23 48 -1 -1 10 15 -0 2 68SS1799 424920 7078665 -0.001 PGM-MS23 0.03 18.8 0.08 44 0.06 0.5 26 10 0.01 1.3 35SS1800 424929 7078740 0.002 PGM-MS23 0.06 16.7 0.2 61 0.08 0.4 12 12 0.03 0.6 54

APPENDIX 2

VTEM Survey Full Report

- Logistics Report on Airborne Geophysical Survey for Error! Reference source not found., Error!Reference source not found.. 24

ProjectQueensland, Error! Reference source not found.

forError! Reference source not found.

Level 560 Edward Street

Brisbane, 4001, AustraliaContact: Nick Mather

Tel: +61 (0) 7 3303 0682Fax: NA

Email: [email protected]

By

Geotech Airborne Limited Suit 7, Manor Lodge No. 3

Lodge Hill, St. Michael, Barbados Tel: 1-246-421-8129Fax: 1-246-417-2999

www.geotechairborne.com

Email: [email protected]

Survey flown in April, 2007


TABLE OF CONTENTS

Executive Summary.................................................................................................................................271. INTRODUCTION................................................................................................................................ 28

1.1 General Considerations...............................................................................................................281.2. Survey and System Specifications...............................................................................................281.3. Data Processing and Final Products............................................................................................28

2. DATA ACQUISITION......................................................................................................................... 292.1. Survey Area................................................................................................................................. 292.2. Survey Operations.......................................................................................................................292.3. Flight Specifications.....................................................................................................................312.4. Aircraft and Equipment................................................................................................................32

2.4.1. Survey Aircraft......................................................................................................................................322.4.2. Electromagnetic System........................................................................................................................322.4.3. Airborne Magnetometer........................................................................................................................342.4.4. Ancillary Systems.................................................................................................................................342.4.5. Base Station..........................................................................................................................................35

3. PERSONNEL...................................................................................................................................... 364. DATA PROCESSING AND PRESENTATION...................................................................................37

4.1. Flight Path.................................................................................................................................... 374.2. Electromagnetic Data..................................................................................................................374.3. Magnetic Data..............................................................................................................................38

5. DELIVERABLES................................................................................................................................ 395.1. Survey Report.............................................................................................................................. 395.2. Gridded Data...............................................................................................................................395.3. Digital Data.................................................................................................................................. 39

6. CONCLUSIONS.................................................................................................................................42

APPENDICES

A. Survey area LocationProject A154

Map.......................................................................................................18B. Survey blocks

coordinates......................................................................................................19C. General modeling results of the VTEM system

………………………………….…..….……. 21D. VTEM Wave Form


July, 2007

- Logistics Report on Airborne Geophysical Survey for Error! Reference source not found., Error!Reference source not 2

………………………………………………..…………………..…….……….. 27


REPORT ON A HELICOPTER-BORNE TIME DOMAIN ELECTROMAGNETIC SURVEY

Mt. Cobalt, Widgee, Elginvale & BanBan Project, Error! Reference source not found.

Executive Summary

As part of the agreement between Geotech Airborne Ltd. and Error! Reference source not found., a helicopter borne geophysical survey has been completed over the Mt. Cobalt, Widgee, Elginvale & BanBan project areas of Error! Reference source not found.. The survey was carried out during the period from April 10th to April 26th, 2007.

Principal geophysical sensors included Geotech’s versatile time domain electromagnetic system (VTEM) and a cesium magnetometer. Ancillary equipment included a GPS navigation system and a radar altimeter. A total of 1113.51 line-km were flown in an area of approximately 152.62 km2.In-field data processing involved quality control and compilation of data collected during the acquisition stage, using the in-field processing centre established at Gympie, Error! Reference source not found.. Final data processing, including generation of final digital data products were done at the office of Geotech Airborne Limited in Pretoria, South Africa.

The processed survey results are presented as total magnetic field and stacked time domain electromagnetic profiles.

Digital data include all electromagnetic and magnetic products, as well as positional, altitude and raw data.


1. INTRODUCTION

1.1 General Considerations

These services are the result of the agreement signed between Geotech Airborne Ltd. and Error! Reference source not found.. to perform a helicopter-borne geophysical survey over the Mt. Cobalt, Widgee, Elginvale & BanBan project areas of Error! Reference source not found..

Nick Mather acted on behalf of Error! Reference source not found.. during data acquisition phases of this project. The survey blocks are as shown in Appendix A. The crew was based in Gympie for the acquisition phase of survey, as shown in Section 2 of this report.

The helicopter was based at Gympie for the duration of the survey. Survey flying was completed by April 26th, 2007. Preliminary data processing was carried out daily during the acquisition phase of the project. Final data presentation and data archiving was completed in the Pretoria office of Geotech Airborne Ltd. by July, 2007.

1.2. Survey and System Specifications

The survey was flown at nominal traverse line spacing of 200 m (Mt Cobalt, Widgee and Elginvale) and 100 m (Ban Ban). in directions N 90° E (Mt. Cobalt), N 150° E (Widgee) and N 0° E (Elginvale and Ban Ban). Tie lines were flown perpendicular to traverse lines at nominal tie line spacing of 2000 m (Mt Cobalt), 1900 m (Widgee) and 1000 m (Elginvale and Ban Ban). The helicopter maintained a mean terrain clearance of 80 metres which translated into an average height of 28 metres above ground for the bird-mounted VTEM system and 68 metres above ground for the magnetic sensor.

The survey was completed using an AS350-B3 helicopter, registration VH-OUF, operated by Heli-Aust. Details of the survey specifications are found in Section 2 of this report.

1.3. Data Processing and Final Products

Data compilation and processing were carried out by the application of Geosoft OASIS Montaj and programs proprietary to Geotech Airborne Ltd. Digital databases, grids and maps of final products were presented to Error! Reference source not found.. The survey report describes the procedures for data acquisition, processing, final image presentation and the specifications for the digital data set.


2. DATA ACQUISITION

2.1. Survey Area

The survey block (see location map, Appendix A) and general flight specifications are as follows:

Blocks

Line spacing

(m)Area (Km2)

Line Distance

(km)Flight

direction Line number

Mt Cobalt 200 11.47 65.20 N 90°E L1010 - 1190T1910 - 1920

Widgee 200 41.28 229.62N150°E

L2010 – 2260T2910 - 2950

Elginvale 200 57.49 341.35 N 0°E L3010 – 3440T9010 - 9100

Ban Ban 100 42.38 477.34 N 0°E L4010 – 4710T4910 - 4970

Table 1 – Survey block

Survey block boundary co-ordinates are provided in Appendix B.

2.2. Survey Operations

Survey operations were based at Gympie for the acquisition phase of the survey.

The following table shows the timing of the survey.Date Crew

LocationFlight # Km

flownComments

10-Apr-07 Gympie 1 65.16One flight, stopped due to windy conditions

11-Apr-07 Gympie 2 73.17One flight, stopped due to windy conditions

12-Apr-07 Gympie 0 ferry to Block #3


13-Apr-07 Gympie 0 ferry to Block #3

14-Apr-07 Gympie 3,4 203.0 Production

15-Apr-07 Gympie 5 101.1 Troubleshooting

16-Apr-07 Gympie Troubleshooting

17-Apr-07 Gympie 6 test Troubleshooting

18-Apr-07 Gympie 7 test Troubleshooting

19-Apr-07 Gympie8 test,9,10,11 138.6 Production

20-Apr-07 Gympie 12 55.0 Production

21-Apr-07 Gympie 13 test Repairs

22-Apr-07 Gympie Repairs

23-Apr-07 Gympie Repairs

24-Apr-07 Relocating 14 12.1 Relocation and Production

25-Apr-07 Kilkivan 15,16 211.05 Production

26-Apr-07 Kilkivan 17,18,19 254.23 Production

Table 2 – Survey schedule


2.3. Flight Specifications

The nominal EM sensor terrain clearance was 28 m (EM bird height above ground, i.e. helicopter is maintained 80 m above ground). Nominal survey speed was 80 km/hour. The data recording rates of the data acquisition was 0.1 second for electromagnetic and magnetometer, 0.2 second for altimeter and GPS. This translates to a geophysical reading about every 2 metres along flight track. Navigation was assisted by a GPS receiver and data acquisition system, which reports GPS co-ordinates as latitude/longitude and directs the pilot over a pre-programmed survey grid.

The operator was responsible for monitoring of the system integrity. He also maintained a detailed flight log during the survey, tracking the times of the flight as well as any unusual geophysical or topographic feature.

On return of the aircrew to the base camp the survey data was transferred from a compact flash card (PCMCIA) to the data processing computer.


2.4. Aircraft and Equipment

2.4.1. Survey Aircraft

An AS350-B3 helicopter, registration VH-OUF- owned and operated by Heli-Aust was used. Installation of the geophysical and ancillary equipment was carried out by Geotech Airborne Ltd.

2.4.2. Electromagnetic System

The electromagnetic system was Geotech’s Versatile Time Domain EM (VTEM) system. The layout is as indicated in Figure 1 below.

Figure 1 – VTEM configuration

Receiver and transmitter coils are concentric and Z-direction oriented.

The receiver decay recording scheme is shown diagrammatically in Figure 2.


Figure 2 – Sample times

Twenty-seven measurement gates were used in the range from 130 s to 8900 s, as shown in the following table.

VTEM Decay Sampling scheme (Microseconds)

Time gate Start End Width130 120 140 20150 140 160 20170 160 180 20190 180 205 25220 205 240 35260 240 280 40300 280 325 45350 325 380 55410 380 445 65480 445 525 80570 525 625 100680 625 745 120810 745 885 140960 885 1045 1601130 1045 1235 1901340 1235 1470 2351600 1470 1750 2801900 1750 2070 3202240 2070 2450 3802660 2450 2920 4703180 2920 3480 5603780 3480 4120 6404460 4120 4880 760


5300 4880 5820 9406340 5820 6860 10407540 6860 8220 13608900 8220 9740 1820Table 3 – VTEM decay sampling scheme.

Transmitter coil diameter was Error! Reference source not found. metres; the number of turns was Error! Reference source not found..

Transmitter pulse repetition rate was 25 Hz. Peak current was 155 Amp.Duty cycle was 46.4%.Peak dipole moment was Error! Reference source not found. NIA.

Receiver coil diameter was 1.2 metre; the number of turns was 100. Receiver effective area was 113.1 m2

Wave form – trapezoid.Recording sampling rate was 10 samples per second.

The EM bird was towed 52 m below the helicopter.

2.4.3. Airborne Magnetometer

The magnetic sensor utilized for the survey was a Geometrics optically pumped cesium vapor magnetic field sensor, mounted on a separate bird towed 12 m below the helicopter, as shown on figure 1. The sensitivity of the magnetic sensor is 0.02 nanoTesla (nT) at a sampling interval of 0.1 seconds. The magnetometer sends the measured magnetic field strength as nanoTeslas to the data acquisition system via the RS-232 port.

2.4.4. Ancillary Systems

2.4.4.1. Radar Altimeter

A Terra TRA 3000/TRI 30 radar altimeter was used to record terrain clearance. The antenna was mounted beneath the bubble of the helicopter cockpit.

2.4.4.2. GPS Navigation System


The navigation system used was a Geotech PC based navigation system utilizing a NovAtel’s WAAS enable OEM4-G2-3151W GPS receiver, Geotech navigation software, a full screen display with controls in front of the pilot to direct the flight and an NovAtel GPS antenna mounted on the helicopter tail.

The co-ordinates of the blocks were set-up prior to the survey and the information was fed into the airborne navigation system.

2.4.4.3. Digital Acquisition System

A Geotech data acquisition system recorded the digital survey data on an internal compact flash card. Data is displayed on an LCD screen as traces to allow the operator to monitor the integrity of the system. Contents and update rates were as follows:

DATA TYPE SAMPLING

TDEM 0.1 sec

Magnetometer 0.1 sec

GPS Position 0.2 sec

Radar Altimeter 0.2 sec

Table 4 - Sampling Rates

2.4.5. Base Station

A combined magnetometer/GPS base station was utilized on this project. A Geometrics cesium vapour magnetometer was used as a magnetic sensor with a sensitivity of 0.001 nT. The base station was recording the magnetic field together with the GPS time at 1 Hz on a base station computer. The base station magnetometer sensor was installed where the crew was based, away from electric transmission lines and moving ferrous objects such as motor vehicles. The magnetometer base station’s data was backed-up to the data processing computer at the end of each survey day.


3. PERSONNEL

The following Geotech personnel were involved in the project

Field Crew Members:

Geophysicist: Anton Rada/ Rafael Coyoli

Operator: Kim Bignell

Geophysicist: Rafael Coyoli

The survey pilot was employed directly by the helicopter operator – Heli-Aust.

Pilot: Tony Feller

Office:Preliminary Data Processing: Rafael Coyoli

Final Data Processing / Reporting: Magdel Combrinck

Final data processing at the office of Geotech Airborne Ltd. in Pretoria, South Africa was carried out under the supervision of Magdel Combrinck.

Overall management of the survey was carried out from the Johannesburg office of Geotech Airborne Ltd. by Keith Fisk, Managing Partner and Director.


4. DATA PROCESSING AND PRESENTATION

4.1. Flight Path

The flight path, recorded by the acquisition program as WGS 84 latitude/longitude, was converted into the WGS 84, UTM zone 56S in Oasis Montaj.

The flight path was drawn using linear interpolation between x,y positions from the navigation system. Positions are updated every second and expressed as UTM eastings (x) and UTM northings (y).

4.2. Electromagnetic Data

A three stage digital filtering process was used to reject major sferic events and to reduce system noise. Local sferic activity can produce sharp, large amplitude events that cannot be removed by conventional filtering procedures. Smoothing or stacking will reduce their amplitude but leave a broader residual response that can be confused with geological phenomena. To avoid this possibility, a computer algorithm searches out and rejects the major sferic events. The filter used was a 16 point non-linear filter.

The signal to noise ratio was further improved by the application of a low pass linear digital filter. This filter has zero phase shift which prevents any lag or peak displacement from occurring, and it suppresses only variations with a wavelength less than about 1 second or 20 metres. This filter is a symmetrical 1 sec linear filter.

The results are presented as stacked profiles of EM voltages for the early as well as late gate times, in linear scale on the preliminary maps and on linear/log scale on the final maps.

Generalized modelling results of the VTEM system, written by Geophysicist Roger Barlow, are shown in Appendix C.

The VTEM output voltage of the receiver coil is shown in Appendix D.


4.3. Magnetic Data

The processing of the magnetic data involved the correction for diurnal variations by using the digitally recorded ground base station magnetic values. The base station magnetometer data was edited and merged into the Geosoft GDB database on a daily basis. The aero magnetic data was corrected for diurnal variations by subtracting the observed magnetic base station deviations.

Tie line levelling was carried out by adjusting intersection points along the traverse lines. A microleveling procedure was then applied. This technique is designed to remove persistent low-amplitude components of flight-line noise remaining after tie line levelling.

The corrected magnetic data from the survey was interpolated between survey lines using a random point gridding method to yield x-y grid values for a standard grid cell size of approximately 0.2 cm at the mapping scale. The Minimum Curvature algorithm was used to interpolate values onto a rectangular regular spaced grid.


5. DELIVERABLES

5.1. Survey Report

The survey report describes the data acquisition, processing, and final presentation of the survey results.

The survey report is provided in PDF format.

5.2. Gridded Data

Total magnetic field grid is provided to Error! Reference source not found. in Geosoft GRD format.

Grid cell size of 50 and 25 metres was used.

5.3. Digital Data

Two copies of CDs were prepared.

There are two (2) main directories for each block,

Data: contains databases, grids and maps, as described below.

Report: contains a copy of the report and appendixes in PDF format.

Databases in Geosoft .GDB format containing the following channels, for each survey block:

X: X positional data (metres – WGS 84, UTM zone 56S) Y: Y positional data (metres – WGS 84, UTM zone 56S) Long: Longitude (WGS 84)Lat: Latitude (WGS 84)Z: GPS antenna elevation (metres - ASL) Gtime1: GPS time (seconds of the day)Radar: Helicopter terrain clearance from radar altimeter (metres) Radarb: EM sensor height terrain clearance (metres)DEM: Digital elevation model data (metres)


Mag1: Raw Total Magnetic field data (nT) Basemag: Magnetic diurnal variation data (nT)Mag2: Total Magnetic field diurnal variation corrected data (nT) Mag3: Levelled Total Magnetic field data (nT)C130f: Raw 130 microsecond time channel (pV/A/m4) C150f: Raw 150 microsecond time channel (pV/A/m4) C170f: Raw 170 microsecond time channel (pV/A/m4) C190f: Raw 190 microsecond time channel (pV/A/m4) C220f: Raw 220 microsecond time channel (pV/A/m4) C260f: Raw 260 microsecond time channel (pV/A/m4) C300f: Raw 300 microsecond time channel (pV/A/m4) C350f: Raw 350 microsecond time channel (pV/A/m4) C410f: Raw 410 microsecond time channel (pV/A/m4) C480f: Raw 480 microsecond time channel (pV/A/m4) C570f: Raw 570 microsecond time channel (pV/A/m4) C680f: Raw 680 microsecond time channel (pV/A/m4) C810f: Raw 810 microsecond time channel (pV/A/m4) C960f: Raw 960 microsecond time channel (pV/A/m4) C1130f: Raw 1130 microsecond time channel (pV/A/m4) C1340f: Raw 1340 microsecond time channel (pV/A/m4) C1600f: Raw 1600 microsecond time channel (pV/A/m4) C1900f: Raw 1900 microsecond time channel (pV/A/m4) C2240f: Raw 2240 microsecond time channel (pV/A/m4) C2660f: Raw 2660 microsecond time channel (pV/A/m4) C3180f: Raw 3180 microsecond time channel (pV/A/m4) C3780f: Raw 3780 microsecond time channel (pV/A/m4) C4460f: Raw 4460 microsecond time channel (pV/A/m4) C5300f: Raw 5300 microsecond time channel (pV/A/m4) C6340f: Raw 6340 microsecond time channel (pV/A/m4) C7540f: Raw 7540 microsecond time channel (pV/A/m4) C8900f: Raw 8900 microsecond time channel (pV/A/m4) PLinef: Power line monitor

Grids in Geosoft .GRD format, as follow,

Mag3_bb: Total magnetic intensity (nT)

A Geosoft .GRD file has a .GI metadata file associated with it, containing grid projection information.

Maps in Geosoft .MAP format, as follow,

A154_Mag_bb: Total magnetic intensity contours and colour image A154_EM_Log_bb: VTEM dB/dt profiles, Time Gates 0.22 - 6.34 ms in linear –


logarithmic scale

where bb = BLOCK Name.

ASCII file VTEM_WaveForm.xyz in Geosoft format contains the following channel:

Volt: output voltage of the receiver coil (volts, sampling rate 20 microseconds)

This file is found in the REPORT directory of the CD.

A readme.txt file describing the content of digital data, as described above.


6. CONCLUSIONS

A versatile time domain electromagnetic helicopter-borne geophysical survey has been completed over the Mt. Cobalt, Widgee, Elginvale & BanBan project areas of Error! Reference source not found..

The total area coverage is approximately 152.62 km2. Total survey line coverage is 1113.51 line kilometres. The principal sensors included a Geotech Versatile Time-Domain EM system and a magnetometer. Results have been presented as colour contour total magnetic field maps and stacked EM profiles at a scale of 1:20,000 and 1:10,000.

A number of EM anomaly groupings can be identified. Ground follow-up of those anomalies should be carried out if favourably supported by other geoscientific data.

Respectfully submitted,

Magdel Combrinck, Geotech Airborne Limited


APPENDIX A

SURVEY AREA LOCATION MAP


APPENDIX B

Mt. Cobalt, Widgee, Elginvale & BanBan PROJECT AREA COORDINATES (WGS 84, UTM ZONE 56S)

UTM_X Z56S UTM_Y Z56S

Mt Cobalt

426650 7100940 426650 7104680429670 7104680 429670 7100940426650 7100940 426650 7100940426650 7100940 426650 7104680429670 7104680 429670 7100940426650 7100940 426650 7100940

Widgee

438700 7103600 442400 7096900437900 7094300 434100 7101200438700 7103600 442400 7096900437900 7094300 434100 7101200

Elginvale

415500 7085100 419100 7085800419800 7082600 423100 7083100424400 7077400 417600 7075900415500 7085100 419100 7085800419800 7082600 423100 7083100424400 7077400 417600 7075900

Ban Ban

394000 7153000 400000 7153000400000 7146000 394000 7146000394000 7153000 400000 7153000400000 7146000 394000 7146000


APPENDIX C

GENERALIZED MODELING RESULTS OF THE VTEM SYSTEM

Introduction

The VTEM system is based on a concentric or central loop design, whereby, the receiver is positioned at the centre of a 26.1 meters diameter transmitter loop that produces a dipole moment up to 625,000 NIA at peak current. The wave form is a bi-polar, modified square wave with a turn-on and turn-off at each end. With a base frequency of 25 Hz, the duration of each pulse is approximately7.5 milliseconds followed by an off time where no primary field is present.

During turn-on and turn-off, a time varying field is produced (dB/dt) and an electro-motive force (emf) is created as a finite impulse response. A current ring around the transmitter loop moves outward and downward as time progresses. When conductive rocks and mineralization are encountered, a secondary field is created by mutual induction and measured by the receiver at the centre of the transmitter loop.

Measurements are made during the off-time, when only the secondary field (representing the conductive targets encountered in the ground) is present.

Efficient modeling of the results can be carried out on regularly shaped geometries, thus yielding close approximations to the parameters of the measured targets. The following is a description of a series of common models made for the purpose of promoting a general understanding of the measured results.

Variation of Plate Depth

Geometries represented by plates of different strike length, depth extent, dip, plunge and depth below surface can be varied with characteristic parameters like conductance of the target, conductance of the host and conductivity/thickness and thickness of the overburden layer.

Diagrammatic models for a vertical plate are shown in figures A and G at two different depths, all other parameters remaining constant. With this transmitter-receiver geometry, the classic M shaped response is generated. Figure A shows a plate where the top is near surface. Here, amplitudes of the duel peaks are higher and symmetrical with the zero centre positioned directly above the plate. Most important is the separation distance of the peaks. This distance is small when the plate is near surface and widens with a linear relationship as the plate (depth to top) increases. Figure G shows a much deeper plate where the separation distance of the peaks is much wider and the amplitudes of the channels have decreased.


Variation of Plate Dip

As the plate dips and departs from the vertical position, the peaks become asymmetrical. Figure B shows a near surface plate dipping 80º. Note that the direction of dip is toward the high shoulder of the response and the top of the plate remains under the centre minimum.

As the dip increases, the aspect ratio (Min/Max) decreases and this aspect ratio can be used as an empirical guide to dip angles from near 90º to about 30º. The method is not sensitive enough where dips are less than about 30º. Figure E shows a plate dipping 45º and, at this angle, the minimum shoulder starts to vanish. In Figure D, a flat lying plate is shown, relatively near surface. Note that the twin peak anomaly has been replaced by a symmetrical shape with large, bell shaped, channel amplitudes which decay relative to the conductance of the plate.

Figure H shows a special case where two plates are positioned to represent a synclinal structure. Note that the main characteristic to remember is the centre amplitudes are higher (approximately double) compared to the high shoulder of a single plate. This model is very representative of tightly folded formations where the conductors where once flat lying.

Variation of Prism Depth

Finally, with prism models, another algorithm is required to represent current on the plate. A plate model is considered to be infinitely thin with respect to thickness and incapable of representing the current in the thickness dimension. A prism model is constructed to deal with this problem, thereby, representing the thickness of the body more accurately.

Figures C, F and I show the same prism at increasing depths. Aside from an expected decrease in amplitude, the side lobes of the anomaly show a widening with deeper prism depths of the bell shaped early time channels.

H IGGG G

E

- Logistics Report on Airborne Geophysical Survey for Error! Reference source not found., Error!Reference source not found..48

A B C

D F


General Modeling Concepts

A set of models has been produced for the Geotech VTEM® system with explanation notes (see models A to I above). The reader is encouraged to review these models, so as to get a general understanding of the responses as they apply to survey results. While these models do not begin to cover all possibilities, they give a general perspective on the simple and most commonly encountered anomalies.

When producing these models, a few key points were observed and are worth noting as follows:

● For near vertical and vertical plate models, the top of the conductor is always located directly under the centre low point between the two shoulders in the classic M shaped response.

● As the plate is positioned at an increasing depth to the top, the shoulders of the M shaped response, have a greater separation distance.

● When faced with choosing between a flat lying plate and a prism model to represent the target (broad response) some ambiguity is present and caution should be exercised.

● With the concentric loop system and Z-component receiver coil, virtually all types of conductors and most geometries are most always well coupled and a response is generated (see model H). Only concentric loop systems can map this type of target.

The modelling program used to generate the responses was prepared by PetRos Eikon Inc. and is one of a very few that can model a wide range of targets in a conductive half space.

General Interpretation Principals

Magnetics


The total magnetic intensity responses reflect major changes in the magnetite and/or other magnetic minerals content in the underlying rocks and unconsolidated overburden. Precambrian rocks have often been subjected to intense heat and pressure during structural and metamorphic events in their history. Original signatures imprinted on these rocks at the time of formation have, it most cases, been modified, resulting in low magnetic susceptibility values.

The amplitude of magnetic anomalies, relative to the regional background, helps to assist in identifying specific magnetic and non-magnetic rock units (and conductors) related to, for example, mafic flows, mafic to ultramafic intrusives, felsic intrusives, felsic volcanics and/or sediments etc. Obviously, several geological sources can produce the same magnetic response. These ambiguities can be reduced considerably if basic geological information on the area is available to the geophysical interpreter.

In addition to simple amplitude variations, the shape of the response expressed in the wave length and the symmetry or asymmetry, is used to estimate the depth, geometric parameters and magnetization of the anomaly. For example, long narrow magnetic linears usually reflect mafic flows or intrusive dyke features. Large areas with complex magnetic patterns may be produced by intrusive bodies with significant magnetization, flat lying magnetic sills or sedimentary iron formation. Local isolated circular magnetic patterns often represent plug-like igneous intrusives such as kimberlites, pegmatites or volcanic vent areas.

Because the total magnetic intensity (TMI) responses may represent two or more closely spaced bodies within a response, the second derivative of the TMI response may be helpful for distinguishing these complexities. The second derivative is most useful in mapping near surface linears and other subtle magnetic structures that are partially masked by nearby higher amplitude magnetic features. The broad zones of higher magnetic amplitude, however, are severely attenuated in the vertical derivative results. These higher amplitude zones reflect rock units having strong magnetic susceptibility signatures. For this reason, both the TMI and the second derivative maps should be evaluated together.

Theoretically, the second derivative, zero contour or colour delineates the contacts or limits of large sources with near vertical dip and shallow depth to the top. The vertical gradient map also aids in determining contact zones between rocks with a susceptibility contrast, however, different, more complicated rules of thumb apply.

Concentric Loop EM Systems

Concentric systems with horizontal transmitter and receiver antennae produce much larger responses for flat lying conductors as contrasted with vertical plate-like conductors. The amount of current developing on the flat upper surface of targets having a substantial area in this dimension, are the direct result of the effective coupling angle, between the primary magnetic field and the flat surface area. One therefore, must not compare the amplitude/conductance of responses generated from flat lying bodies with those derived from near vertical plates; their ratios will be quite different for similar conductances.


Determining dip angle is very accurate for plates with dip angles greater than 30º. For angles less than 30º to 0º, the sensitivity is low and dips can not be distinguished accurately in the presence of normal survey noise levels.

A plate like body that has near vertical position will display a two shoulder, classic M shaped response with a distinctive separation distance between peaks for a given depth to top.

It is sometimes difficult to distinguish between responses associated with the edge effects of flat lying conductors and poorly conductive bedrock conductors. Poorly conductive bedrock conductors having low dip angles will also exhibit responses that may be interpreted as surfacial overburden conductors. In some situations, the conductive response has line to line continuity and some magnetic correlation providing possible evidence that the response is related to an actual bedrock source.

The EM interpretation process used, places considerable emphasis on determining an understanding of the general conductive patterns in the area of interest. Each area has different characteristics and these can effectively guide the detailed process used.

The first stage is to determine which time gates are most descriptive of the overall conductance patterns. Maps of the time gates that represent the range of responses can be very informative.

Next, stacking the relevant channels as profiles on the flight path together with the second vertical derivative of the TMI is very helpful in revealing correlations between the EM and Magnetics.

Next, key lines can be profiled as single lines to emphasize specific characteristics of a conductor or the relationship of one conductor to another on the same line. Resistivity Depth sections can be constructed to show the relationship of conductive overburden or conductive bedrock with the conductive anomaly.

VTEM3 Waveform - April 25, 20075

4

3

2

1

0

Volts

-1

-2

-3

-4

-5

0 10 20 30 40 50 60 70Time (ms)

- Logistics Report on Airborne Geophysical Survey for Error! Reference source not found., Error! Reference source not found..52

APPENDIX DV

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