Lyons River Lead Zinc Copper Project
Lyons River is located approximately 1,100km north of Perth and approximately 220 km to the north-east of the coastal town of Carnarvon, Western Australia.
Lyons River Project location diagram
Location diagram showing geological setting
Regional and local geology
The Lyons River Project lies within the Mutherbukin Zone of the Gascoyne Province, which is the deformed and high-grade metamorphic core zone of the early Proterozoic Capricorn Orogen. The Mutherbukin Zone is 50km wide and trends WNW-ESE, bounded to the north by the Ti Tree Shear Zone and to the south by the Chaliba Shear Zone. These south-dipping, crustal-scale structures delineate the margins of the Mutherbukin Zone and separate it from the older Limejuice Zone to the north and the Mooloo Zone to the south.
Detailed airborne magnetic survey, on 50m line-spacing, over the project area has enabled a geological interpretation which shows the structure of the project area to be dominated by a west northwest striking domal feature. Magnetics show the dome to be cut by several north-northeast trending faults and mafic dykes whilst the north western area (the region of possible intrusion and complex folding) is separated by northwest striking faults.
Geology Gascoyne Province structural and metamorphic zones after GSWA Record 146.
Exploration completed to date
GSWA's semi-regional stream sediment sampling in the late 1990s, with a sample density of 1 sample per 16km2 within the Lyons River Project, highlighted a cluster of samples with elevated Ag and Pb coincident with gahnite. A 2003 gahnite study by BHP, following the analysis of heavy mineral samples collected during earlier diamond exploration, highlighted the BHT Pb-Zn-Ag potential. In particular, the prospectivity of the Proterozoic Morrissey Metamorphic Suite. The presence of gahnites is interpreted to be related to BHT base metal mineralisation.
BHP reconnaissance soil and rock chip sampling and geological traverses defined a 6 km long Pb-Zn-Cu soil anomaly coincident with gahnite-bearing and Pb-anomalous drainages. The soil anomalies were coincident with weathered manganiferous and garnetiferous schists/gneisses with up to 990 ppm Pb, as well as gossanous float with up to 0.14% Zn.
Systematic auger geochemistry was completed in 2008, where previous BHP geochemistry had returned anomalous Pb and Zn values coincident with “thumbprint” magnetic anomalies with values of up to 566 ppm Zn and 1150 ppm Pb. Auger geochemical Pb Zn anomalies were RC drill tested at Area 1/Four Corners intersecting predominantly, high-grade metamorphics (quartz-biotite-garnet gneiss) probably derived from pelitic sediments. Base metal values were intersected in holes GRC004, 014 and 016 of up to 2.3% Pb, 0.6% Cu and 0.3% Zn. The drilling defined a mineralised trend striking NE-SW and parallel to the stratigraphy. The alteration and sulphide mineralisation outlined was postulated to be peripheral to a larger base metal deposition.
Three generations of IP surveys at Area 1 in 2008, 2012 and 2017, initially in the immediate vicinity of drill hole GRC004, have demonstrated that IP is likely to be an effective exploration technique. The IP surveys have been successful in delineating a major north-east trending polarisable zone and 2 polarisable zones outlined east of the central zone exhibit south-west to north-east trend. The largest of these is the north-east (NE) zone. Both the NE and SE zones extend beyond the limit of the IP surveys and remain open to the east. Soil geochemical sampling completed over Area 1/Four Corners reveal anomalous Pb Zn values, the patterns showing some correlation with the NE and SE IP zones. All three polarisable zones have been the focus of the recent diamond drill program.
Four Corners – Isometric view down toward NW of 3D Induced Polarisation model (compiled from 2D inversions of 100m dipole-dipole traverses completed in 2012 and 2017) showing chargeable zones and 2008 drill holes.
Exploration programs undertaken by a number of companies in the Lyons River area over the previous 15 years have outlined substantial clusters of IP anomalies that are coincident with anomalous zinc and lead soil geochemistry over a strike of 2.5km. Combination of all previously completed exploration work has led to the development of a conceptual model that suggests the Lyons River Project is prospective for Broken Hill Type (BHT) deposits.
Geoscience Australia’s 2019 study, using surface wave tomography and a parameterisation for anelasticity at seismic frequencies shows 85% of the world’s sediment hosted base metal deposits occur within 200km of the edges of thick lithosphere. The Australian model shows striking correlation between major sediment hosted deposits and edge of thick lithosphere, defined by 170km LAB contour. Lyons River Project is located 156km from the 170km LAB contour.
Distribution of SEDEX deposits, function of lithospheric thickness in Australia
In addition, large systematic soil geochemical surveys conducted from 2017 at Lyons River Project over approximately 20km of stratigraphy has outlined another four geochemical targets.
Lyons River Four Corner prospect and additional targets
In December 2020, 1,364m of diamond core was drilled in four drill holes to test the very significant 2.5 km strike length IP chargeability anomalies with coincident soil anomalism and historical 2008 RC drill results.
Diamond drilling has delineated, a signature SEDEX/BHT lithological package with interpreted psammitic and pelitic rocks which have undergone high grade metamorphism and alteration and are comprised of biotite-quartz-anorthoclase-corderite-sillimanite. These metamorphosed rocks have subsequently been intruded by the Davey Well granite batholith and pegmatite dykes. Significant intervals of disseminated/blebby pyrite and pyrrhotite occur within the IP chargeability zones which was the focus of the recently completed diamond drilling program. Coeval galena, and chalcopyrite and sphalerite have been observed. pXRF spectral results of Pb 3.58% and Zn 3.72% have been recorded. Varying amounts of chalcopyrite have been observed in most of the holes.
The following work is earmarked to be completed on the Lyons River Project over the coming months comprising:
1. Petrographic studies are underway to confirm mineral assemblage and define SEDEX lithological package.
2. Quarter core drill samples have been sent for analysis
3. Consultant geophysicist has recommended that downhole IP surveys be undertaken in some of the holes, based on the large sulphide intervals being intersected. There is a case for DHEM due to the presence of significant pyrrhotite in drill hole LRDD004. Geophysical contractors are being investigated to undertake the downhole geophysical surveys.
Drill hole location map with historical holes, recent rock chip sample results and diamond hole locations.
Further information on the Namban and Lyons River projects can be found in the Independent Geologist Report Attachment 1 to of the Prospectus.