EPM 29362 - BIG BEND

Exploration Permit for Minerals (EPM) 26633, known as the Big Bend tenement, is located approximately 60–70 kilometres northwest of Chillagoe township in North Queensland, and to the northwest of the Mungana and Red Dome copper–gold mines on Wrotham Park Station.  The tenement forms part of the Diversified Mining and Resources Pty Ltd (DMR) Palmerville Project, for which applications were lodged in December 2025.

The tenement was previously held by Prophet Resources and was jointly explored with adjacent EPMs held by Native Mineral Resources Ltd (ASX: NMR). Diversified Mining and Resources and its partners have since consolidated the project area through the aggregation of three contiguous EPMs, completing the land package.

The Big Bend tenement is so named due to its position over a major flexure, or hinge zone, within the Palmerville Fault. In this area, the regional structural trend of the fault changes from a northwest–southeast orientation in the south to a north–south orientation in the north, representing a significant structural feature with potential implications for mineralisation.

Limited surface exposures of altered rhyolite and andesitic volcanic or intrusive rocks occur within the Big Bend area. These exposures lie sub-parallel to, and east of, the Palmerville Fault, and are locally associated with a northeast-trending cross fault. These rocks have been attributed to the Permian Nychum Volcanics, which post-date significant gold and base metal mineralisation. An alternative interpretation is that these rocks may belong to the Carboniferous Pratt Volcanics, which occur to the south and are known to host gold mineralisation.

The Big Bend area represents a strong conceptual exploration target. It lies along strike from known mineral deposits developed on the Palmerville Fault trend, is interpreted to share similar host geology, occurs at a major flexure within the fault system, and exhibits a magnetic response suggestive of a complex intrusive architecture and subsequent deformation.

PALMERVILLE 2023 Airborne Geophysical Survey

Native Mineral Resources (NMR) completed an extensive airborne magnetic and radiometric survey across the Palmerville Project, targeting the Chillagoe Formation and surrounding geological units including the Big Bend EPM. The survey commenced on 6 April 2023 and concluded in May 2023 as part of a broader Palmerville Project survey undertaken in collaboration with the Queensland Government under the Collaborative Exploration Initiative (CEI).

BIG BEND IMAGES

The reduced-to-pole (RTP) magnetic image for the Big Bend area is presented in Figure 2. The magnetic response is complex and dominated by a large area of intense RTP magnetic lows in the central part of the study area. In addition, several smaller, more discrete RTP lows are present throughout the area.

These RTP lows are classic indicators of reverse remanent magnetisation, which occurs when rocks crystallise during periods in which the Earth’s magnetic field was reversed relative to the present-day field direction.

Recognition of reverse remanent magnetisation is particularly important in North East Queensland, as it commonly indicates a Late Carboniferous to Early Permian age, a period during which the Earth’s magnetic field was dominantly reversed. Many large mineralised systems in North East Queensland are associated with reverse remanent magnetic features, making these responses a valuable indicator of intrusive-related hydrothermal systems with potential for associated mineralisation.

Several magnetic data transformations can be applied to confirm the presence of reverse remanent magnetisation and to correct for the associated RTP lows. Two of the most useful transforms are the Vector Residual Magnetic Intensity (VRMI) and the Analytical Signal.

The Analytical Signal, also known as the total gradient transform, is insensitive to the direction of magnetisation and is therefore a robust tool for analysing data affected by remanent magnetisation. The Analytical Signal produces a positive response over magnetic material regardless of whether the magnetisation is induced or remanent.

The VRMI represents the magnitude of the three orthogonal components (Bx, By, Bz) of the anomalous magnetic field. Where full vector magnetic data are available, VRMI can be calculated directly. When only total magnetic intensity (TMI) data are available, the three components can be derived using Fourier-based methods and subsequently combined to calculate VRMI. Like the Analytical Signal, VRMI is insensitive to magnetisation direction and yields positive responses over all magnetic sources.

The VRMI image for the Big Bend area is presented in Figure 3, and the Analytical Signal image in Figure 4. In both images, the principal magnetic responses are expressed as positive anomalies, simplifying interpretation. Consequently, subsequent analysis and interpretation of the Big Bend magnetic data were conducted primarily using the VRMI and Analytical Signal images, along with various derivatives and transforms of the VRMI.

A simple radiometric ternary image of the Big Bend area is presented in Figure 5.

MAGNETIC 3D INVERSION MODELLING

To assist in investigation of the magnetic formations and structures at Big Bend, 3D magnetic inversion modelling has been completed. Unconstrained 3D inversion modelling of the VRMI magnetic data was completed using MGinv3D from Scientific Computing and Applications. The model cell size used was 80m x 80m, with cells 40m thick to a depth of 2000m and then with increasing thickness to beyond 5000m.
Topography data derived from the 2023 Palmerville Airborne survey was included in the model process. The 3D model was unconstrained so there was no controls on the magnetic susceptibility that could be allocated by the inversion to each cell.
The inversion results are presented as a depth slice at 300m below the surface through the 3D model in Figure 6. Depth slices from 100m to 1500m depth are also provided as GeoTIFF images with this report. A 3D perspective view of two selected iso-shells derived from the 3D inversion model is presented in Figure 7. A full range of iso-shells are also provided as 3D DXF files for display in any 3D software.

INTERPRETATION

The airborne magnetics at Big Bend clearly define a diamond shaped zone of complex magnetic responses with bounding structures in the NE and NW directions. This is seen clearly in the VRMI (Figure 3) and Analytic Signal images (Figure 4). There are also numerous NE and NW structures cutting across and through the magnetic zone. The interpretation of this signature is fairly straight-forward with the complex likely to be due to magnetic intrusive rocks which have been subsequently deformed by the NE and NW structures. The age of the intrusives is likely to be Late Carboniferous to Early Permian indicated by the presence of reverse remanent magnetisation.
The trace of the Palmerville Fault is well defined particularly in some of the derivative images (not provided here, see images previously provided) and can be mapped across the whole Big Bend study area including where the fault zone changes direction. There are also some discrete circular magnetic zones down the eastern side of the study area to the east of the Palmerville Fault.
A simple geophysical interpretation has been completed using various images of the magnetic data, the 3D inversion model, and the radiometric data. The interpretation has concentrated on mapping primary structures, areas where the intrusives are potentially shallowest, and any other anomalous features in the magnetic and radiometrics. The interpretation is presented in Figure 8 and is supplied as a QGIS Geopackage file which will load directly into QGIS with the symbology as shown in Figure 8 retained. The interpretation is also provided in KML format for Google Earth although the symbology will not be correctly retained.
The interpretation shows that the most magnetic and shallowest parts of the intrusive complex occur around the edges of the system, particularly along the SE, SW, and NE margins. This is also illustrated in the depth slices through the 3D inversion model (Figure 6) and the 3D iso-shells (Figure 7). The inversion model suggests that these marginal magnetic zones are steep-sided and sub-vertical.
There are numerous cross cutting faults through the system which are dominantly either NE or NW trending. The complexity of the magnetic response makes it difficult to determine the relative timing of these two fault directions from the geophysical data. 

Further analysis of the interpretation with regards to exploration targets is presented later in this report, following a discussion of the 2007 VTEM survey.

BIG BEND 2007 VTEM SURVEY

The Big Bend VTEM survey was one of six survey blocks flown on the Kagara Zinc Ltd Chillagoe/Boyd project in 2007 by Geotech Airborne. The Big Bend block was flown using 100m spaced EW lines for a total of 706 line kilometres. Survey coverage is shown in Figure 1.
The relevant Kagara Zinc Annual Report (EPM14602 Annual Report to 6th April 2008; CR53114) states identified 10 targets of interest for drill testing. A full report from SGC was not included, however a table of proposed drill holes to test the ten targets, and the SGC modelling plots were in an Appendix.
Follow up work completed by Kagara included Fixed Loop Electromagnetic (FLEM) surveys over some of the VTEM anomalies, and subsequent drill testing of six targets.

Initial review of the VTEM data by Mitre suggested that there was many more anomalies in the VTEM data than the ten listed in the Kagara report. It was decided to complete a new full anomaly picking exercise on the VTEM data to ensure that all anomalies were considered in the current review.

The anomaly picking is completed in two main stages :

• The data is analysed in profile and image form and any anomalous or interesting response is marked on the profiles (anomaly “picks”). The output from this process is a SHP file including locations and parameters for all of the anomaly picks (also supplied as a KML file).
• The picks are then turned into Anomaly Groups by drawing a polygon around each set of picks which belong to the same conductor. This is an efficient way to synthesize all of the picks into a more transparent and efficient targeting dataset. The anomaly groups are attributed with a description, likely source, geophysical rank, and generalised recommended follow up and is provided as a polygon SHP file (and a KML file).

The anomaly groups are identified with a name and a ranking. The name is a unique identifier which in this case is either VTxx (xx being a number) or for anomalies that were previously identified by SGC then SGC_Targetx is used. The ranking is a letter from A (highest ranking) to D (lowest ranking) based primarily on initial analysis the EM signature.
The final ranking of the VTEM anomalies includes comparison with other exploration data such as magnetics, geology, geochemistry, drilling etc, using roughly the following rationale (this is the Rank attribute in the Anomaly Group SHP file):

1. Limited strike length moderate to strong conductors are considered higher priority targets, especially if upgraded by interpreted structures or other geophysical responses, such as the magnetics.
2. Limited strike length weak to moderate responses are considered moderate priority.
3. Broad, smoothly varying, high amplitude responses are most often due to conductive overburden or stratigraphic conductors, especially if over a large area. However, there is
   potential that good conductors can be buried beneath the cover, so these anomalies cannot
   always be completely ignored.
4. Targets previously investigated by SGC and Kagara, and adequately explained, are included in this rank.

Twenty-five (25) anomaly groups have been identified by this process. These are illustrated in Figure 9 and listed in Table 1. There are seven VTEM Anomaly Groups which are ranked highest and a further our ranked second highest. The anomalies have been checked against the modelling of the VTEM and FLEM data completed by SGC as well as drilling results to determine whether the anomalies have already been adequately explained. In three cases the anomalies that were initially ranked highly have been fully tested and explained by Kagara drilling, and thus had their final ranking reduced to the lowest level.
Anomaly summary sheets are provided in Appendix 1 for the anomalies with the highest ranking (1 & 2). These plots capture the major features of each target area in detail. The summary sheets show the location of the anomaly picks against the EM response, magnetics, and aerial images, the EM profiles illustrating the anomaly form, and include comments and general recommendations for follow up of each anomaly group.
The highest ranked VTEM targets are discussed further in the following section on the selection of conceptual exploration targets.

EXPLORATION TARGETS

Conceptual exploration targets have been selected for the Big Bend area based on the magnetic, radiometric and VTEM data, and the geophysical structural interpretation presented in Section 3.3.
Criteria for selecting the exploration targets were as follows :

• Clearly anomalous geophysical response from either the magnetic, radiometric or VTEM data.
• Areas of structural intersections or structural complexity, especially in the vicinity of the Palmerville Fault although not limited to that corridor.
• Coincidence of structural or geophysical anomalism obviously increases the tenor of the exploration target.

Twenty-seven (27) conceptual exploration targets have been selected on this basis. The targets are listed in Table 2 and presented in Figure 10 on the VRMI magnetic image and Figure 11 with the geophysical structural interpretation. The targets are also provided as SHP and KML files.

The exploration target areas are identified by a name and a ranking. The name is a unique identifier which in this case is BBxx (xx being a number). The ranking is a letter from A (highest ranking) to C (lowest ranking). Targets with coincident structural and geophysical anomalism are generally ranked highly, while the more conceptual targets with less confidence are ranked lower.
Along with the priority ranking, the targets are also classified by type, based on what dataset their definition was primarily based on (structure, magnetic, radiometric, VTEM, or combinations of these). Any targets with a VTEM response are cross-referenced with the VTEM Anomaly Group name from Section 4.

For further information and analysis of the Big Bend EPM, please contact Diversified Mining and Resources.