The Mount Coolon Gold Project (MCGP), 100% owned by GBM, is located within the Drummond Basin, one of Queensland’s most prolific gold provinces. Located 250 km to the West of Mackay in North Queensland, the tenement package covers a total area of over 2,613 km². The area has seen historic gold production to the 1900’s totalling 0.59 Mt at 12.2 g/t Au for 232 koz gold.
On 21 October 2022, GBM announced a Farm-in agreement with Newcrest on the MCGP tenements.
Highlights:
- 2,613 km² tenement package in the highly prospective Drummond Basin
- 100% owned by GBM Resources, subject to Newcrest Farm-in agreement
- Historic production to 1990’s totalling 0.59 Mt at 12.2 g/t Au for 232 koz gold
- Current resources of 6.65 Mt @ 1.54 g/t Au for 330 koz gold
- 2021 drill programme doubled strike extent of Glen Eva gold system
- Extensive geophysical program in early 2021 has outlined a large trend between Glen Eva and Eastern Siliceous Zone (GEES) that looks extremely prospective
- Many targets identified in large-scale gold bearing epithermal system for further drilling
Resource
A JORC 2012 resources identifies gold in three zones, Koala, Glen Eva and Eugenia:
The current open pit resources at Koala/Eugenia/Glen Eva are calculated at a gold price of A$1,667/oz - well below the prevailing spot price of >A$2,500/oz. Note: Newcrest has not verified these mineral resource estimates.
Exploration
Following GBM’s restructure in late 2019 a 3,415 m initial diamond core and RC drill program was conducted at the MCGP in 2020, with a follow up program in later 2021 of 6,197 m. The programs were designed to test targets adjacent to existing resources, and to identify a pipeline of exploration targets for future work. This is part of GBM’s immediate goal to build a 2-3 million ounce resource in the Drummond Basin region.
Results were positive with highlights including:
- Drill hole 20GEDD011 intersected a 13.4 m wide epithermal vein hosting 8.9 m @ 1.66 g/t Au and 18.6 g/t Au from 281.1 m. This hole doubled the strike extent of the Glen Eva gold system, and provided strong epithermal vectors for future drilling.
- An IP geophysics survey conducted alongside the drilling program identified a target outlined by a large, open ended, low order chargeability and resistivity anomaly localised at a permissive structural intersection.
- Drill hole 21GEDD017 intersected 14.6 m @ 1.15 g/t Au within a 57 m wide zone of intense epithermal veining.
The extended strike and the geophysics anomaly provide key exploration targets for a more detailed drilling program to be conducted in 2022. The project is a large-scale gold bearing epithermal system that warrants significant further drill testing.
GEES Mineralisation Model and Exploration Strategy
The results of the 2021 and 2020 drill programs have demonstrated a substantial multi-stage hydrothermal system is present at GEES. Zoning across epithermal systems has been well documented at several deposits and a Pb-Zn to Au-Ag-Te to Au-As-Sb zoning consistent with other epithermal deposits is present at GEES.
Given the position of the IP chargeability anomaly along strike from Glen Eva pit and the CBM veins intersected in 21GEDD019, GBM interprets the anomaly, and associated abundant disseminated pyrite, to represent the concealed alteration halo of a large hydrothermal system. We infer that the Glen Eva epithermal veining, the pyrite halo, and CBM veining may be part of a large mineral system that zones outward from a base metal bearing core to a low sulfidation precious metal system to the northwest at Glen Eva (Figure 4) and potentially also to the southeast at Eastern Siliceous. This is a preliminary interpretation and requires additional drill testing over 1.5 km of intervening untested strike projection of the vein corridor back to Glen Eva and over 2 km of intervening untested strike towards Eastern Siliceous.
Gold mineralisation along the GEES trend displays clear Au-As-Sb and Au-Ag-Te ± Mo-Bi element associations while vein textures suggest the best grades may be shoot controlled. GBM plans to use detailed surface geochemistry in conjunction with surface mapping, IP and magnetics to identify favourably oriented fault segments that are coincident with the key Au element associations. This combined structural and geochemical targeting will initially focus on Glen Eva and Eastern Siliceous and then be extended along the entire GEES trend. The combined geochemical and structural anomalies will be ranked and drill tested for high grade shoots.
The 3D and 2D IP surveys completed in 2020 and 2021 respectively failed to directly image the Glen Eva vein. This is surprising given the substantial width and strike of the vein and proximity of the vein to the surface. In conjunction with geophysics programs on other prospects, GBM plans to run selected Controlled Source Audio Magnetotellurics (CSAMT), a low-impact ground geophysical survey method to test lines across the Glen Eva vein. If CSAMT successfully maps the Glen Eva vein then this technique will also be used to test coincident geochemical and structural anomalies prior to further drilling.
Scoping Study and Project Options
A 2017 scoping study on the MCGP demonstrated the technical and economic viability of:
- Open pit and underground mining of the Koala, Glen Eva & Eugenia deposits
- Processing and gold recovery via a combination of CIL leaching and heap leach.
The study, conducted by Mining One consultants, with input from external consultants, indicated excellent projected margins, cashflow and returns.
It is GBM’s view that the opportunity in the Drummond Basin is much larger than just the MCGP. Since late 2019, GBM has been aggressively pursuing expansion to target a 2-3 million ounce gold resource, through both strategic acquisition, exploration (JV or GBM funded). GBM sees the opportunity to integrate the Yandan, Twin Hills and Mount Coolon gold projects, processing at centralised facilities and realise significantly more upside than each individual project could achieve by itself.