The Browns Reef deposit lies 5km west of the town of Lake Cargelligo in an area primarily used for agricultural purposes, including grazing and cropping.
The Project’s previous owner, Kidman Resources, defined a JORC 2012 Exploration Target for the Browns Reef deposit, based on 52 diamond drill holes and 22 RC holes, of 27 to 37 million tonnes grading between 1.3-1.4% zinc, 0.6-0.7% lead, 9-10g/t silver and 0.2-0.3% copper. The potential quantity and grade of this Exploration Target are conceptual in nature and there has been insufficient exploration to define a Mineral Resource. It is uncertain if further exploration will result in the determination of a Mineral Resource. Eastern Metals confirms that it is not in possession of any new information or data that materially impacts on the reliability of this estimate.
Eastern Metals’ strategy at Browns Reef is to identify areas within the Exploration Target envelope where higher-grade zones of base metals mineralisation may occur.
The key target identified for follow-up exploration is the Evergreen Zone, which is centred near the historical hole BRD013 drilled by previous owner Kidman Resources, which returned 7.0m grading 5.5% Zn, 2.3% Pb, 0.5% Cu, 20.2g/t Ag and 0.5g/t Au.
Eastern Metals completed drilling at Browns Reef over the first half of 2022, with a series of high-grade assay results defining the Evergreen lode zone over a strike length of more than 150m and a vertical depth of 300m, with the mineralisation remaining open along strike in both directions and at depth. Highlights from the drilling included 12.5m grading 8.1% Zn, 2.6% Pb, 0.10% Cu, 17.3g/t Ag and 0.5g/t Au from 269.5m (BRD019).
A subsequent gravity survey clearly mapped the main trend of the mineralisation at Evergreen, while also highlighting additional anomalies with similar characteristics that could also be associated with mineralisation.
An air-core drilling program has been planned to test these anomalies and other prospective structures.
Eastern Metals’ focus for the 2024 Financial Year will be on delivering a JORC Mineral Resource at Browns Reef, while also focusing on target generation through systematic data acquisition for further exploration across this exciting project.
Browns Reef – Geology
Browns Reef is a polymetallic deposit developed in the Preston Formation, a sedimentary sequence of Devonian age. It is close to the Woorara Fault, a regional-scale structure that may have formed a pathway for mineralising fluids.
Browns Reef is a stratabound or stratiform deposit that was discovered in the late 19th century with shallow shafts sunk in the 1930s and was worked briefly for gold. The lode trends north-northwest where the Preston Formation consists of steeply dipping volcanic sandstones, siltstones and black shales. The lode contains pyrite, sphalerite and galena, along with minor gold and chalcopyrite mineralisation.
Modern exploration commenced in the 1970s, when six diamond holes were drilled. Since then, several drilling programs have been completed by various tenement holders. Lead isotope data suggests that Browns Reef could be similar to the New Cobar and CSA base and precious metal systems at Cobar.
Outcrop of the prospective Preston Formation in the Browns Reef tenement is poor. Most of the bedrock is covered by Quaternary colluvium, alluvial and minor aeolian material. Elsewhere within the tenement Tertiary basalts also obscure the basement rocks.
The known deposit at Browns Reef occupies a small part of the tenement. Most of the deeper drilling to date has been confined to a zone about 2.7km long in the central to southern part of the tenement where the Preston Formation dips steeply to the west.
Tara, Bothrooney & Black Range
Tara (EL9180), Bothrooney (EL9136) and Black Range (EL9565) represent exciting secondary targets within the Company’s Cobar Project.
Eastern Metals has identified prospective geology within each of these licence areas, with exploration programs to be undertaken in parallel with the Company’s primary work program focused on the delivery of a JORC Mineral Resource Estimate at Browns Reef.