Southern Hemisphere Mining (ASX: SUH) has kicked off reverse-circulation (RC) drilling at its Llahuin copper-gold-molybdenum play in Chile, with two holes already completed in its planned 5000m RC and diamond drill campaign.
Details of the program were revealed three weeks ago when the company said it had entered into a contract for the drilling to begin in early October in a bid to establish a resource upgrade for the project’s 680,000-tonne copper equivalent endowment. The drilling will be directed toward increasing copper tonnage and grade at Llahuin, better defining the deeper core of its big Cerro-Ferro deposit that has more than 2km of strike and to advance its big Curiosity copper-gold porphyry target with a deep diamond drillhole from an RC pre-collar following further work to refine the target.
RC drilling will initially focus on the near-surface copper-gold mineralisation intersected in an RC hole drilled last year, which jagged 48m at 0.48 per cent copper equivalent from surface. It represents a new zone south of Ferro – which Southern Hemisphere says was part of its southern soil anomaly – that had not been previously drilled and looks like an opportunity to add higher-grade, near-surface tonnage to the resource.
Management says another important objective is to extend an existing diamond hole drilled to 644m in 2013, which offers a lower-cost extension to about 1200m depth into a target north of Cerro.
Additional recent work has included a comprehensive 409-sample rock-chip and pulp resampling program on a 200m grid across most of the company’s concession area to home in on deeper targets at both Cerro-Ferro and Curiosity.
Southern Hemisphere points out that recent heavy rains have exposed prospective porphyry rocks north-east of Ferro through an area of about 200m that hosts previously untested copper-molybdenum soil anomalism and that area is now being followed up with channel and rock sampling.
Several samples have tested epithermal vein outcrops at Curiosity, coming up with grades of up to 0.69 per cent copper, 7.38 grams per tonne gold, 8.3g/t silver and 459 parts per million molybdenum, supporting the potential for the zone to host one or more big copper targets.
Expert independent opinion has suggested that geophysics might be a useful tool to guide ongoing exploration at Curiosity and the deeper Cerro targets and the company is currently considering that option and its best timing. Geophysics could well assist with defining the Cerro Deeps target zone and with the Cerro resource nearby, it would be a logical first location to apply the method given the already high level of confidence management has in the target and the potential capacity to extend the overall Cerro resource.
The two recently-completed holes were put into the new South Ferro target – which was initially defined by soil sampling – and will follow up mineralisation intersected in last year’s RC hole that intercepted the 48m at 0.48 per cent copper equivalent from surface.
The final proofs will all be in the pudding stirred by the latest drilling, with results expected from the ALS Global laboratory in Santiago mid-next month.
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