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MINOTAUR EXPLORATION LTD 247 Greenhill Road, Dulwich 5065, South Australia Tel: +61 8 8366 6000 Fax: +61 8 8366 6001 Website www.minotaurexploration.com.au Email admin@minotaurexploration.com.au A.C.N. 108 483 601 Subject: Coolibah Bore – Ground magnetic survey: Interpretation Report Author: Louise McAllister Tenement: Coolibah Date: 22nd November 2011

Introduction The Coolibah tenement is located 250kms northeast of Alice Springs in the Northern Territory, and covers part of the Eastern Arunta province where Palaeoproterozic metasediments and metaigneous rocks outcrop from shallow Cainozoic cover (figure 1).

Figure 1 Coolibah tenement showing outcropping geology.

The region is known to host Cu, Pb-Zn and Sn, with the Jervois Copper deposit located to the northeast of the tenement. Sub-cropping vanadium rich magnetite bodies have recently been discovered that correlate with magnetic highs along a NW-SE trending structure. The southern continuation of this structure passes through the Coolibah tenement (figure 2). Several EM anomalies have also been identified along this structure within the tenement.

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Figure 2 RTP HSI magnetic image for the Coolibah tenement, fault traces have been outlined in black, along with mineral occurrences and EM anomalies.

A further area of interest in this tenement is close to Coolibah Bore, here a coincident gravity/magnetic fold hinge anomaly is observed (figure 3).

Figure 3 Regional aeromagnetic RTPHSI image with 1VD gravity contours showing the coincident gravity and magnetic anomalies. The ground magnetic survey area is outlined in orange.

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Between the 24th June and 6th July, 142.8 km of ground magnetic data was collected at Coolibah Bore in order to more clearly define the magnetic features in this area (figure 4). Figure 4 Regional aeromagnetic RTPHSI image with ground mag lines over the area of interest at Coolibah Bore.

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Survey Logistics The ground magnetic work was conducted in house by Minotaur Exploration using a G859 magnetometer. Survey lines were spaced at 200m intervals and data collected every second as the operator walked the line. The survey details are summarised in the following tables:

Target Line_Northing StartE FinishE Length (m) Ori (°)

Coolibah Bore 7460600 641700 645900 4200 90

Coolibah Bore 7460800 641700 645900 4200 90

Coolibah Bore 7461000 641700 645900 4200 90

Coolibah Bore 7461200 641700 645900 4200 90

Coolibah Bore 7461400 641700 645900 4200 90

Coolibah Bore 7461600 641700 645900 4200 90

Coolibah Bore 7461800 641700 645900 4200 90

Coolibah Bore 7462000 641700 645900 4200 90

Coolibah Bore 7462200 641700 645900 4200 90

Coolibah Bore 7462400 641700 645900 4200 90

Coolibah Bore 7462600 641700 645900 4200 90

Coolibah Bore 7462800 641700 645900 4200 90

Coolibah Bore 7463000 641700 645900 4200 90

Coolibah Bore 7463200 641700 645900 4200 90

Coolibah Bore 7463400 641700 645900 4200 90

Coolibah Bore 7463600 641700 645900 4200 90

Coolibah Bore 7463800 641700 645900 4200 90

Coolibah Bore 7464000 641700 645900 4200 90

Coolibah Bore 7464200 641700 645900 4200 90

Coolibah Bore 7464400 641700 645900 4200 90

Coolibah Bore 7464600 641700 645900 4200 90

Coolibah Bore 7464800 641700 645900 4200 90

Coolibah Bore 7465000 641700 645900 4200 90

Coolibah Bore 7465200 641700 645900 4200 90

Coolibah Bore 7465400 641700 645900 4200 90

Coolibah Bore 7465600 641700 645900 4200 90

Coolibah Bore 7465800 641700 645900 4200 90

Coolibah Bore 7466000 641700 645900 4200 90

Coolibah Bore 7466200 641700 645900 4200 90

Coolibah Bore 7466400 641700 645900 4200 90

Coolibah Bore 7466600 641700 645900 4200 90

Coolibah Bore 7466800 641700 645900 4200 90

Coolibah Bore 7467000 641700 645900 4200 90

Coolibah Bore 7467200 641700 645900 4200 90

Total line km 142.8km

Table 1 Summary of survey lines.

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All co-ordinates are given in GDA 94, MGA Zone 53S. The survey was conducted between 24th June and 6th July, a summary of daily operations is given in table 2 below: Date Activities Notes 24-06-11 Mobilise to site 25-06-11 Set up Base station and survey L7467200 and L7467000 Base station ok 26-06-11 Survey L7466800, L7466600, L7466400 and L7466200 Base Station ok 27-06-11 Survey L7466000, L7465800, L7465600 and L7465400 Base station ok, gap in L7465600 to be repeated 28-06-11 Survey L7465200 and L7465000 Base station ok 29-06-11 Survey L7464800, L7464600 and part of L7464400 Base station not working, roving mag used 30-06-11 No acquisition, only gap in L7465600 repeated Base station not working, roving mag used 01-07-11 Survey L7464400 and L7464200 Base station ok, but roving mag used to take base readings

too. Roving unit GPS not working, marks taken every 100m 02-07-11 Tom Martyn returns to Adelaide and is replaced by Julian

Bates

03-07-11 Survey L7464000, L7463800, L7463600, L7463400, L7463200 and L7463000

Base station ok

04-07-11 Survey L7462800, L7462600, L7462400, L7462200, L7462000 and L7461800

Base station ok

05-07-11 Survey L7461600, L7461400, L7461200, L7461000, L7460800 and L7460600

Base station ok

06-07-11 Demobilise to Alice Table 2 Summary of daily operations.

The following table summarises the survey details: Survey Equipment Magnetometer Geometrics G-859 magnetometer Base Magnetometer Geometrics G-856 magnetometer Survey Specifications Line Direction East-West Line Spacing 200 metres Survey Speed Walking pace Sample Interval 1 per Second Table 3 Survey details.

Diurnal corrections were calculated using data from the base station data where readings were taken at 30 second intervals throughout the day. The base station was located at the following co-ordinates:

Coolibah Bore 640495E 7464734N GDA94 Zone 53

The magnetic field for Coolibah Bore was as follows:

Field Intensity 52476nT Inclination -54.37° Declination 5.66°

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Data Quality The data quality throughout the survey was good. As noted in table 3 above, base station data was not recorded on 29th and 30th of June, instead data was collected by the roving unit by returning frequently to the base station location. On the 1st the Roving unit GPS unit failed, the track was marked every 100m and the missing GPS co-ordinates were interpolated in Geosoft. Individual noisy data points as shown in figure 5 were removed in Geosoft.

Figure 5 Example of individual noise point on line L746700 which has been removed from the final dataset.

Topographic information is not presented in this report as the integrated GPS unit is not adequately accurate in the Z direction.

Data Processing

The roving magnetic data was corrected for diurnal magnetic variation, using the base station data. A 5m upward continuation was applied to the line data and saved as an additional column in the data file. The data was gridded at 50m cells then reduced to pole and a first vertical derivative filter applied. The following FFT filters were also applied; Analytical Signal, Tilt and Tilt Gradient, these filters enhance regional structures and the edges of magnetic anomalies. 2D Modeling 2D modeling was conducted along profiles extracted from the TMI grid with a 1m sample interval. Profiles were orientated perpendicular to the dominant geological strike direction.

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The regional magnetic field was calculated using a first polynomial fit. 2D models were calculated using the residual magnetc data. Simple model responses were created using tabular bodies. In the following sections the modeled bodies are coloured according to their magnetic susceptibility as described below:

Magnetic Susceptibility SI Value Range Colour Low <0.1 Moderate ≥0.1 to <0.2 High ≥0.2

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Results The ground magnetic data for Coolibah Bore has resolved the regional magnetic highs (figure 6), into a series of sinuous lineations trending approximately north-south through the centre of the survey area. The RTPTMI image is dominated by a large magnetic high of 3000nT in the southern section of the grid (figure 7). This magnetic anomaly covers an area of almost 1.5 sq km and is elongated along a north-west to south-east trend. The southern margin of the magnetic high is well defined, terminating on an east-west trending structure. Likewise the eastern extent of the magnetic anomaly is also marked by a northwest-southeast striking structure. The outline of this structure is marked on its western side by isolated magnetic highs of 1000 – 2000nT, which show elongation along a northwest-southeast axis. On the other hand the eastern side of this structure is characterised by areas that are magnetically quiet. This structure can be traced throughout the length of the survey grid. A lower amplitude magnetic high is also observed to the west of the main anomaly, up to 750nT and covering an area of 0.2 sq km. Many of the thin sinuous features seen in the RTPTMI can also be seen in the RTP1VD image (figure 7), however the main magnetic anomaly described above is shown to consist of a number of small discontinuous highs in the 1VD. The main structures are also evident by comparision of the magnetic textures on each side of these features. In the ½VD image (figure 8a) the southern magnetic features in particular appear more continuous while the greyscale RTP1VD image (figure 8b) enhances the lateral continuity of the shallow magnetic features, some of which are more difficult to identify in the coloured RTP1VD image.

Figure 6 Regional aeromagnetic RTPHSI data for Coolibah Bore with the area of the ground magnetic survey shown in orange.

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Figure 7a) RTPTMI b) RTP1VD c) Traverse over peak of magnetic anomaly, traverse shown in figure 7a.

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Figure 8 Greyscale RTP1VD magnetic image, gridded at 100m cell size, helps to enhance the lateral continuity of the shallow magnetic features.

2D and 3D Model

2D modeling was conducted along three profiles, two in the northern portion of the survey and one in the south (figure 9). The profiles were selected where the magnetic anomalies are largest. The northern magnetic anomalies are modeled as a series of thin, steeply east and west dipping, tabular bodies. The magnetic features here are generally limited in strike length and are represented on single profiles, either CB_01 or CB_02 (figures 10 and 11). Depth to top of the modeled bodies is approximately 130m, with susceptibilities ranging from 0.05 SI to 0.35 SI. Along the southern profile, nine steeply SE and NW dipping bodies where using to match the TMI and 1VD curves. A reasonable fit is achieved except in the middle of the profile where the magnetic features appear to alter strike direction from NW to NE. The magnetic bodies are model at a depth of approximately 130m, with susceptibilities of between 0.06 SI and 0.26 SI.

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Figure 9 2011 Coolibah Bore RTPTMI image with the modeled profiles highlighted in pink, and the modeled magnetic bodies in black.

Figure 10 Modeled results along profile CB_01.

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Figure 11 Modeled results along profile CB_02.

Figure 12 Modeled results along profile CB_02.

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Modeled characteristics for the main bodies are summarised in table 4.

Body Name Colour Susceptibility

(SI) Depth (m) Width (m) Dip (°)

CB04 0.11 130 185 85 CB05 0.11 139 71 85 CB06 0.35 132 105 80 CB11 0.105 140 288 80 CB12 0.12 127 154 85 CB13 0.21 131 193 85 CB17 0.15 125 107 80 CB18 0.15 130 165 80 CB19 0.19 131 252 80 CB20 0.26 122 167 80 CB21 0.26 130 244 80

Table 4 Modeled parameters.

The 3D model shows the discontinuous and variable nature of the magnetic response at Coolibah Bore (figure 13). The northern magnetic features, although sporadic, do show a clearer strike direction and here the 2D bodies correlate reasonably well with the 3D model in terms of dip and depth to top (figure 14 and 15).

Figure 13 Plan view of 3D magnetic model for Coolibah Bore, with RTPTMI image. b) The main 2D modeled bodies are shown.

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Figure 14 Slice through 3D model along profile CB_01.

Figure 15 Slice through 3D model along profile CB_02.

Along profile CB_03, the 2D modeled bodies and 3D model match well, however the strike direction and lateral continuity here is more difficult to acertain (figure 16).

Figure 16 Slice through 3D model along profile CB_03.

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Discussion

The ground magnetic data has improved the resolution of the regional airborne magnetic dataset to reveal a series of sinuous lineations trending approximately north-south through the centre of the survey area. In the southern section of the survey area a large; 3000nT magnetic anomaly dominates the RTPTMI image (figure 17). This magnetic high is coincident with a gravity anomaly (figure 18). The 1.5 mgal gravity anomaly extends to the north and west, beyond the peak of the magnetic features (figure 18), however the overall magnetic package resolved during this survey correlates well with the peak of the gravity anomaly (figure 19). The gravity anomaly is not sufficiently resolved to model in conjunction with the magnetic bodies.

Figure 17 Ground magnetic RTPTMI image on top of regional aeromagnetic image.

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Figure 18 Regional 1VD gravity image for Coolibah Bore overlain with contours of the magnetic anomaly ≥53000nT. Contours interval is 500nT. The gravity stations are shown as green circles.

Figure 19 Regional 1VD gravity image for Coolibah Bore, the 52000nT contour line traced in white delineates the moderate to high magnetic features resolved by this survey, and shows good correlation with the peak of the gravity anomaly.

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Numberous RAB holes have been drilled over EL 27733, with a few within the magnetic survey area (figure 20). Assuming that the holes were drilled to refusal, shallow cover sequences are suggested as end-of-hole depths were in the order of 10-20 meters. This is at odds with the 2D modeling which suggests a depth to magnetic basement of 130m. The discrepancy between the depth of cover and the magnetic modeling may in part be due to depth of weathering. No indication is given in the RAB logs as to the nature of bedrock.

Figure 20 Part of Jervois tenement with RAB drilling shown. Black number denote the final depth of the hole.

Summary

The ground magnetic survey has successfully defined the airborne magnetic features. In the northern part of the survey the magnetic features here are resolved as a series of thin parallel lineations with a general north-south trend. To the south, a large, 3000nT magnetic anomaly dominates the RTPTMI image and covers an area of approximately 1.5 sq km. The magnetic features are modeled at depths of around 130m, with typical magnetic susceptibilities of 0.1 SI and up to 0.35 SI. The association of the magnetic features with a 1.5mgal gravity anomaly suggests a mafic source. The Jervois Cu mineralisation is hosted in magnetite-bearing schists which are analogous to Broken Hill Type/ Thackaringa Style mineralisation.

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A local gravity grid should be considered in future to better resolve the gravity anomaly at Coolibah Bore and determine its association with the magnetic features identified the 2011 Ground Magnetic Survey.