Yes, a very strong newsflow week, and all of it positive, on...

Yes, a very strong newsflow week, and all of it positive, on both our Western and Eastern Corridors - and now in the Met lab too:


Friday - Confirmation by way of decent grades at Pegasus that it is indeed a new primary gold discovery, nice and shallow, which appears to form part of a much larger mineralised system along the Western Corridor at Cardinia - which extends from Pegasus in the south through to Bruno and Kyte in the north. (Shallow Gold Discovery Confirmed at Pegasus, 25/05/22)


Monday - Again, some very healthy grades (including 2m at 14.5g/t Au), extending Cardinia Hill northward and corroborating that the Eastern Corridor area is strongly endowed with multiple structurally controlled ore positions, all of which contain high grade sulphide and quartz vein mineralisation that has a common source. (High Grade RC Drilling Results Extend Cardinia Hill, 27/05/22)


Wednesday - Still more, one might even say outstanding results, from Helens East - this time including an intersection of 7m at 24.7g/t Au! Won't take too much like that to make a significant block contribution to the MRE. And yet again reinforcing that the extensive mineralised environment in the Eastern Corridor contains multiple mineralised positions extending over a total strike distance of 5km. (Significant HG Mineralisation Discovered at Helens East, 01/06/22)


Today - News of a tweak for significantly improved recoveries on our sulphide ores: The improvement in recovery over the conventional grind, gravity and leach process is substantial, increasing recoveries by 6.3% at Cardinia Hill, 10.9% at Helens and up to 12.6% at Lewis. These results indicate that sulphide ores from Cardinia, if treated using the flotation and re-grind process, are likely to result in significantly improved gold production and financial returns.


Music to my ears that "improved gold production and financial returns" are percolating to the fore in management's strategic thinking.



Also, I thought this was interesting from an historical perspective. Good to think that today's reported Sighter testwork might so convincingly overcome earlier shortcomings:


Interpretation and Implications

A number of metallurgical testwork programs were undertaken at Cardinia up until 2019, including the completion of the 2019 Pre-Feasibility Study which showed high metallurgical recoveries generally based on oxide and transitional ore samples available up until that point in time. Optimisation work by IMO showed conventional 150μm grind, gravity and 48-hour leaching resulting in, on average, 94.5% recovery for Oxide and Transitional ore types across Cardinia.

Test work at that time also showed generally lower metallurgical recovery for fresh ores associated with sulphide mineralisation. Metallurgical recovery of Variability Composites showed recoveries of between 68.7% and 91.1% for Helen’s sulphide ores and between 76.6% and 91.1% for Lewis sulphide ores using the conventional grind-gravity-leach process. Weighted average recovery for Fresh sulphide ores from Cardinia averaged 81.5%.

When applied as modifying factors to mining and processing production estimates during the 2019 PFS, these results significantly reduced the proportion of fresh sulphide ore able to be economically extracted and reduced pit design depth, ore supply and estimated economic return in the 2019 PFS.

Flotation, rougher concentrate regrinding and leaching under optimal conditions has shown significant improvement in sulphide ore metallurgical recovery, increasing recoveries by up to 12.4% at Lewis, 12.6% at Helens and 6.3% at Cardinia Hill on samples tested to date. These results indicate that coarse Primary Grind, Rougher Flotation and regrinding of concentrates prior to leaching is likely to be included in the flow sheet for treatment of sulphide ores from Cardinia.

Metallurgical recovery is likely to be approximately 97% for Cardinia Hill sulphide ores based on optimal conditions testwork, 91% for Helens and 87% for Lewis sulphide ore based on Sighter testwork completed to date.