The Merredin Project covers 219km² and is located on granted Exploration Licence E70/6810 and exploration licence application E70/6831. It is located approximately 30km from the Edna May gold processing plant, which is currently on care and maintenance. The project has access to established regional infrastructure including road and rail networks.
The Merredin Project is interpreted to be prospective for gold mineralisation following developments in recent years in understanding of gold deposition controls in the Yilgarn. The project also has potential for iron ore and base metals mineralisation.
The Merredin tenure is considered prospective due to the presence of strong magnetic signatures, indicating presence of mafic-ultramafic and Banded Iron Formation (BIF) lithologies within a strongly metamorphosed margin of Yilgarn Craton granitoids. Presence of mafic granulite and BIF has been confirmed by previous tenement holders of the area.[1] Previous workers on the tenement area noted thick transported granitic sheetwash areas up to 23m thick obscuring the basement lithologies.[2] They noted enclaves of highly metamorphosed mafic and BIF units in the limited drilling that has been completed on the ground.
The magnetic units define a large fold closure in the 20m aerial magnetics dataset published by the Geological Survey of Western Australia (GSWA)[3] with 14.5km of the fold axis within the Merredin Project tenements. Late cross faults in a NE orientation cut the folded structure. A significant crustal scale shear/fault is interpreted in a NW trend through the tenure.
The combination of folding and faulting, in addition to the position marginal to large granitoids with suspected greenstone relicts, is a favourable geological setting for gold mineralisation. GSWA has characterised several of the surrounding granite units within the Sanukitoid series, increasing the prospectivity of the region for gold mineralisation. The Edna May gold deposit, 30km to the east, is hosted within a gneiss enclave of metamorphosed diorite alongside a major NW trending major crustal shear, adjacent to a granite classified as ‘probable sanukitoid’ by the GSWA study.[4] Sanukitoid granites represent A type granites from deep crustal melts, rather than highly fractionated I type granites. They are considered more likely to be associated with gold mineralising fluids than other granite types in the Yilgarn Craton.
Historically, high-grade metamorphic terranes in Western Australia have been considered less prospective for gold mineralisation. This view is based on the understanding that gold-bearing hydrothermal fluids are mostly mobilised and deposited at mid- to upper-crustal levels, typically under greenschist to lower amphibolite facies conditions. In contrast, deeper crustal rocks subjected to higher-grade metamorphism tend to undergo ductile deformation due to elevated temperatures and pressures, reducing their propensity to fracture, dilate and develop the structural pathways required for fluid flow and gold deposition.
Gold exploration during the past 25 years in Western Australia provides mounting evidence that gold mineralising events occurred later than peak metamorphic grade, with opportunity for mineralisation in a later event once the rocks are in a shallower crustal position, cooler and more brittle. Multiple known gold deposits in Western Australia are in high-grade metamorphic terranes, including Boddington Gold Mine and Katanning Gold Project in the Yilgarn Craton and Tropicana Gold Mine in the Plumridge Terrane.
[1] 2016; Fethers, G.; ‘Surrender Report E 70/3769 for the period 19 April 2010 to 14 April 2016, Bullamine Project, Western Australia’; DMPE WAMEX report A108990; Perth, Western Australia
[2] 2024; Karius, S.; ‘Final Surrender Report Burracoppin for the Period 15 July 2020 to 5 July 2024; DMPE WAMEX report A144620; Perth, Western Australia
[3] Brett, JW 2023, 20m magnetic merged grid of Western Australia 2023 version 1: Geological Survey of Western Australia, www.dmp.wa.gov.au/geophysics.
[4] Lowrey, JR, Smithies, RH, Champion, DC and Cassidy, KF 2023, Systematic classification of Yilgarn Craton granitic rocks: Geological Survey of Western Australia, Record 2023/12, 27p.
