Project Group Summary

The Frewena Group of projects lies 120-260km east of Tennant Creek in the Northern Territory, within the emerging East Tennent region, and includes the Frewena Fable, Frewena East, Frewena Far East, and Frewena Frontier Projects that collectively cover 5,362km². The projects are joint ventured with Inca Minerals Ltd with MRG retaining a 5-10% free-carried interest and 0.75-1.5% NSR.

The East Tennent region lies between the mining centres of Tennent Creek and Mount Isa and is a frontier exploration terrane covered by sedimentary lithologies of the Georgina Basin. Given its location between major mining centres, its underexplored nature, and occurrence of relatively shallow basement along the East Tennent gravity ridge, the region was selected by Geoscience Australia (GA) and the Northern Territory Geological Survey (NTGS) as a multidisciplinary study area to assess for base and precious metal potential.

During 2018-2021, GA and NTGS undertook a series of geophysical surveys including airborne electromagnetics, magnetotellurmetrics, seismic, and ground-based gravity to provide high resolution data to better constrain knowledge of basement rocks, and their metallic prospectivity, across the region. This work culminated in a stratigraphic drill campaign undertaken by MinEx CRC completed in late 2021, with the region experiencing a tenure pegging rush by major miners and junior explorers following lifting of an exploration licence moratorium that was in place while the pre-competitive studies were in progress.

While exploration of the East Tennent region remains in its infancy, the excellent pre-competitive work by GA, NTGS, and MinEx CRC has since been further advanced by exploration companies through the use of additional geophysical surveying and drill testing. The East Tennent region is considered prospective for a variety mineralisation styles including IOCG/ISCG and SEDEX, as well as diamonds, in Proterozoic-aged basement lithologies, in addition to large-scale, shallow phosphate accumulations within the Georgina Basin sedimentary rocks, which includes the giant Wonarah and Arruwurra phosphate deposits owned by Avenira (ASX:AEV).

Further information regarding the Frewena Group Projects can be found via Inca Minerals’ ASX announcements at www.asx.com.au/markets/company/icg or www.incaminerals.com.au

IOCG-SEDEX Potential

Exploration undertaken to date across the Frewena Group has included a comprehensive review of all GA-NTGS-MinEx CRC generated pre-competitive data, geological reconnaissance, c. 84,000-line km of detailed airborne magnetic-radiometric surveying, 410km² ground gravity surveying, drill targeting studies, and 8,474m of reconnaissance drill testing.

Figure 2: Selection of core photos from FW220007 at Mount Lamb Northeast

Significant, large-scale IOCG-style targets at a number of prospects across the Frewena Group were primarily identified using a combination of magnetic, gravity, and – where available – seismic data. These conceptual targets lie beneath 150-220m of Georgina Basin sediments and the Helen Springs Volcanics, making them some of the shallowest targets in the East Tennent region. In particular, the scale of the magnetic and gravity anomalies along the >15km long Mount Lamb trend compares favourably to those of known Tier-1 IOCG deposits including Prominent Hill, Carrapateena, and Ernest Henry.

Reconnaissance drill testing in 2022 included eight deep (c. 1,000m), holes spread over the priority Mount Lamb Northeast, Mount Lamb Southwest, Jumping Spider, and Roadhouse prospects with RC precollars between 120-209m deep followed by diamond tails. Holes were designed to drill through modelled magnetic and gravity anomalies to provide a first-pass test of geology associated with these features.

While economic grade mineralisation was not encountered during this reconnaissance drill program, widespread, metallic-enriched hydrothermal alteration was intersected in all eight deep holes at the four prospects tested, including wide intervals of strong IOCG-style alteration at Mount Lamb Northeast with elevated Au-Ag-Cu-Fe-Bi-Mo. Reconnaissance drilling results are considered a major technical success that validates the Frewena Group exploration model and the robustness of the magnetic and gravity modelling used for drill targeting.

Confirmation of metallic fertility of the area enhances the East Tennent’s potential to host large-scale IOCG mineralisation, in addition to other mineral systems, with the results from first pass drilling of blind, conceptual geophysical targets in a greenfield, frontier terrane an outstanding achievement at such an early stage of exploration.

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  Figure 3: Frewena East and Frewena Far East TMIRTP on 2vd-agc image showing planned and completed 2022 drill holes with drilling activity focussed on the large-scale Mount Lamb magnetic-gravity trend.

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  Figure 4: Comparison of Mount Lamb magnetic (upper image) and gravity (lower image) anomalies with known IOCG deposits highlighting the size significance of the Mount Lamb trend.

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  Figure 5: Cross-section of the Mount Lamb 3D magnetic model showing geology and magnetic susceptibility of drill-holes FW220007, FW220008 and FW220009, highlighting the robustness of the geophysical modelling. Note that the magnetic model in the vicinity of FW220008 (c. 1.7km away along strike) has been clipped for simplicity. For sense of scale, FW220009 drill trace is 1,051m long.

Phosphate JORC Exploration Target

A review of historical phosphate exploration from the late 1960s to 2011 in the area surrounding Avenira’s (ASX:AEV) Wonarah phosphate deposit highlighted three areas within EL32857 where wide spaced drillholes returned elevated phosphate grades of up to 39.5% P₂O₅.

The Wonarah and nearby Arruwurra phosphate deposits, owned by Avenira, are considered as one of the largest phosphate resources in Australia hosting a Total Resource of 533Mt (15% P2O5 cutoff grade) that includes (source: www.avenira.com/):

• Measured Resource of 64.9 Mt @ 22.4% P₂O₅
• Indicated Resource of 133 Mt @ 21.1% P₂O₅
• Inferred Resource of 335 Mt @ 21% P₂O₅

The sedimentary phosphate mineralisation at Wonarah is flat lying and laterally continuous over a large area. Historical drilling surrounding Wonarah confirms mineralisation continues within EL 32857 and it is considered likely for phosphate horizons to occur in other undrilled portions of the Frewena Group tenure. Regional gravity data indicates sizeable subbasins occur within the Frewena East and Frewena Frontier Projects that appear similar to the subbasin hosting Wonarah, with exploration drilling required to test this hypothesis.

Historical drill data within EL 32857 was of sufficient density to develop a phosphate JORC Exploration Target to guide future exploration endeavours with three Exploration Target areas – Wonarah North, Wonarah South, and Wonarah East – defined immediately adjacent to Avenira’s mining lease. Full details regarding the JORC Exploration Target, including the criteria involved in compilation and review of historical phosphate exploration drilling and assay data and the calculation of Exploration Target, can be viewed here.

The total weighted upper and lower range JORC Exploration Target for the combined Wonarah North, South, and East areas within EL 32857 are as below, with full details presented in Table 1:

• Lower Range: 452.9Mt at 14.7% ₂O₅.
• Upper Range: 761.1Mt at 17.9% P₂O₅.