Southern Hemisphere Mining (ASX: SUH) has scored strong gold hits up to 7.38 grams per tonne in rock chip samples collected to refine modelling of the Curiosity and Ferro-Cerro Deeps targets at its Llahuin copper-gold play in Chile.
The company recently picked up 156 new rock chip and 73 drill pulp samples to better inform its geophysical and geochemical 3D modelling, which initially highlighted the two key target areas. Management regards Curiosity and Ferro-Cerro Deeps as compelling, deeper copper-gold targets that warrant drilling.
Significant results from the latest rock-chip sampling include the headline 7.38g/t gold hit with 8.13g/t silver in one sample, 0.59g/t gold and 1.44g/t silver in a second sample and 0.22 per cent copper in a third. The additional rock chip samples were taken on a grid that infilled and extended the previous 47 rock chip layout, achieving a largely uniform pattern spaced between about 100m and 200m across the sampling area.
A further 135 samples were taken from an adit at the Santa Maria gold mine that sits immediately above the Curiosity target.
The multi-element analytical results from Santa Maria reveal the characteristic signature of a high-sulphidation epithermal environment, from which the possibility of an underlying deep and extensive porphyry system at Curiosity may be inferred. The original sampling and modelling and the latest infill and extension follow-up sampling have improved the definition of the two target areas before drilling, with the goal of lifting Llahuin’s resource numbers prior to an imminent mining study.
Southern Hemisphere is canvassing tenders from four Chilean companies for a proposed 5000m drilling program that will target higher-grade zones through the extensive strike of the Cerro-Ferro system. The target top at Santa Maria is interpreted to be 550m vertically below the epithermal gold system that has pipe-like geometry with a diameter of about 1km.
The initial drilling is proposed to comprise reverse-circulation (RC) holes to about 250m depth, targeting resource expansion and the company may also install pre-collars for later drilling of deeper targets. Any later deep diamond drilling will look at the practicality of re-entering previous drillholes where possible to reduce overall costs.
The previous 2013 JORC-compliant measured, indicated and inferred resource estimate for the Llahuin project sits at 680,000 tonnes of copper equivalent.
In addition to drilling and the assessment of rock chip data, an extensive portable XRF (pXRF) program of multi-element analysis has been undertaken across all laboratory pulps from previous campaigns. The program picked up several zones of elevated molybdenum that were left unassayed in the original drilling.
The pXRF anomalous samples have been selected for wet assay and will be included in the pending resource update. Hyland Geological and Mining Consultants has been engaged to undertake an update to the mineral resource estimate, which is timed for the first quarter of next year.
Minerals processing and engineering consulting company Sedgman has also been engaged to perform metallurgical test work on samples from within the current mineral resource to build on previous studies undertaken in 2013.
Southern Hemisphere has encountered compelling porphyry copper-gold-moly signatures at Llahuin and now has the bit all but literally between its teeth as it ties everything together for a solid go at lifting its resource numbers at the project and putting together a strong mining model.
It will then be interesting to see the first scout hole put into the top of the appropriately-named Curiosity target to find out just how good the 3D porphyry modelling is.
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