Geology

Geological Setting and Mineralisation

Gold mineralisation at Ebagoola South is deposited as both epithermal and mesothermal quartz veins, sheeted veinlets and breccias associated with the large regional Ebagoola Shear (NNW trending) and subsidiary structures and Permian intrusives emplaced along NE trending corridors (Figure 2).

The geological setting is similar to the large IGRS at Kidston (5 Moz gold), Ravenswood SW (3 Moz gold), Mount Leyshon (3.5 Moz gold) within the Northeast Queensland Mineral Province further to the south.

Up to sixteen IRGS targets have historically been identified at Ebagoola South (Figure 3), including:

• Spion Kop - a 200m diameter rhyolite and rhyolite breccia complex, similar in geological setting to the giant Kidston deposit, with widespread arsenic anomalism and a repeatable and coherent gold anomaly along the eastern slope.
• Lapunya Mount – an intrusive coinciding with a prominent reverse magnetic anomaly located at the intersection of the Ebagoola Shear Zone and the later NE trending Flying Fox-Lapunya linear (fracture) zone (Figure 4), a setting possibly similar to Mt Leyshon.

^{Source: Geo Data Pty Ltd, Independent Geologist's Report
Figure 3. Schematic of the IRGS targets located within the Ebagoola South tenement (after Stirton, 1998)}

^{Source: Geo Data Pty Ltd, Independent Geologist's Report
Figure 4. Lapunya Mount reverse magnetic anomaly - Total Magnetic Intensity - Reduced to Pole - Linear Colour Stretch}

Yarraden – an area with up to seventeen, poorly outcropping, generally NE - SW striking epithermal quartz veins that overprint the mineralised mesothermal quartz veins at the historic Golden King, Savannah and Lady Jane prospects. The epithermal veins have considerable strike lengths, and before are narrow (generally less than 50 cm) and low grade (0.5 g/t Au maximum) at surface. Quartz vein textures typical of the chalcedonic zone and anomalous arsenic (to 379 ppm) and antimony (to 16.35 ppm) suggest a high level of erosion and the possibility that the gold grade could increase at depth.

^{Source: Geo Data Pty Ltd, Independent Geologist's Report
Figure 5.   Location of historic mesothermal gold mines and other prospects}

Ebagoola South hosts a further fourteen historic gold mines that exploited mesothermal quartz veins and minor related alluvials and elluvials (Figure 5). Mining was selective, focussing on high-grade ore shoots (32 to 72 g/t Au) generally above the water table (25m below surface). Many of these prospects exhibit considerable widths of wall rock sheeted and stockwork veins and breccias, adjacent to the historically exploited main lodes. The gold bearing veins are usually associated with Early Permian rhyolite, quartz porphyry and locally mafic dykes and anomalous in arsenic and other indicator elements (molybdenum, tin and tungsten). These factors suggest that they may represent peripheral zones to large Early Permian IRGS in the district.

Priority mesothermal prospects include:

• Golden King-Savannah-Lady Jayne – historic hard rock mine workings over a 900 m strike extent.
• Lukin King - historical mine workings over a zone up to 60 m wide and extending for 650 m along strike.
• Gold Mount – historic workings over a 200 m strike extent.