Moonlight Resources has swapped out the rigs at its Leo Grande gold prospect in central Queensland, kicking off targeted diamond drilling hot on the heels of its recently completed reverse-circulation (RC) campaign.
While the earlier reverse-circulation (RC) drilling was largely chasing metres, the new focused four-hole, 500-metre program is more about drilling for details. The campaign marks Moonlight’s next step of building a modern picture of Leo Grande ahead of putting a maiden resource around the system.
The company inherited 70 historical drill holes for 4620m at Leo Grande, where shallow, widely spaced drilling had repeatedly hit gold, while leaving the bigger question of continuity and depth largely unanswered. Its first RC campaign began filling those gaps, hitting gold in every hole and returning up to 40m at 1.3 grams per tonne (g/t) gold from surface.
Phase 2 then substantially expanded the known extent, extending coherent mineralisation beyond 1km, with results including 19m at 1.95g/t gold from 99m and 40m at 1.31g/t gold from 76m, including 5m at 3.40g/t. Together, the completed RC campaigns provided the samples needed to establish the position and grade of gold mineralisation across Leo Grande.
The drilling has also helped build the company’s geological interpretation of Leo Grande as a shear-hosted gold system developed through strongly deformed rocks, where repeated deformation can create pathways and traps for mineralising fluids. Its interpretation associates gold with quartz veining, silicification, pyrite and chlorite alteration and allows for multiple mineralised lodes across the broader structural width.
Results have revealed broad gold intervals from surface and shallow depths, with locally stronger zones. Moonlight believes the defined 1km-plus mineralised footprint lies within a structural corridor that extends almost 4km and spans roughly 60m. With multiple holes ending in mineralisation, management says Leo Grande remains open along strike and at depth.
Moonlight Resources managing director Greg Starr said: “The first two phases of RC drilling have substantially advanced our understanding of the scale and continuity of the Leo Grande system and this new, targeted diamond drilling programme has been designed to provide a much higher level of geological and structural information.”
To take the company's technical understanding up a gear, Moonlight has brought in United Drilling Services to pull oriented diamond core from Leo Grande, giving its geologists a ringside view of the structures controlling the gold and a sharper handle on the system’s geometry and orientation.
The fresh-rock core will also provide samples for metallurgical testwork to assess how the mineralisation responds to processing. Together, the structural and metallurgical datasets will feed into geological modelling as the company works towards the maiden resource estimate.
Leo Grande sits within the 268-square-kilometre Clermont gold project, 15km west of the Queensland township of the same name in the Drummond Basin. The proven gold province is credited with more than 6.5 million ounces of historical production and endowment and offers the added bonus of established drilling access and favourable infrastructure.
While Leo Grande is the company’s most advanced gold prospect and resource-definition focus, Clermont also hosts the Goldfinger and Petersens gold prospects and Peak Downs copper prospect. Recent drilling at Peak Downs confirmed copper mineralisation across an area largely defined by historical work, echoing the strategy used at Leo Grande of applying modern exploration to old datasets and progressively building a new geological picture.
Elevated gold prices continue to fuel corporate activity and consolidation across the Australian gold sector, with producers hunting scale. Explorers capable of building defined, growing resources are therefore attracting plenty of attention. That backdrop gives the push to turn Leo Grande’s growing mineralised footprint into a maiden resource added relevance.
For Moonlight, with more than a kilometre of coherent mineralisation established, the diamond rig is being rolled in to pin down how the system fits together and add the technical detail needed to advance the geological model. This short, sharp campaign could provide key pieces to complete the technical puzzle needed to table that all-important maiden resource at Leo Grande.
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By Penny Taylor
