Initial drilling by operator Westmin Resources (WMI-T) at Yamana Resources’ (YRI-T) Arroyo Rojo massive sulphide prospect in Argentina has defined significant copper-lead-zinc mineralization beneath surface showings.
The drill program is part of the Fin del Mundo project, near Ushuaia in the National Territory of Tierra del Fuego.
Previously, the showings were reported to contain up to 0.8% copper, 3.9% lead, 18.9% zinc, as well as 0.9 gram gold and 50.9 grams silver per tonne, over 4.4 metres of trenching.
Six holes totalling 1,450 metres were completed on Arroyo Rojo, testing downdip extensions of the surface showings over a strike length of 250 metres. The work demonstrated that mineralization extends to a depth of at least 100 metres.
Holes 1, 2 and 3 penetrated the main sulphide horizon and intersected wide-spread disseminated-To-stringer or laminated pyrite and base metal mineralization in a footwall. Hole 3 showed the highest-grade interval: 2.2% copper, 3.7% lead, 9.4% zinc, and 0.06 gram gold and 65 grams silver over 6.9 metres (83.3 to 90.2 metres), or 3.7 metres of true thickness.
Hole 4, the westernmost hole, failed to intersect significant base metal mineralization, while hole 1, the easternmost, showed that the mineralized body remains open to the east beneath talus.
Hole 5 was a shallow, 120-metre test of a geophysical target, the Rio Encajonado prospect, situated 800 metres northeast of Arroyo Rojo. It found the anomaly was associated with a narrow pyrrhotite band.
Assay results are pending for holes 6 and 7.
Sargent prospect
Drilling is under way on the Sargent prospect, 5 km northwest of Arroyo Rojo.
Initial drilling will test the downdip extensions of a surface showing, which assayed 4% copper over 4 metres in intensely chloritized rhyolite.
Arroyo Rojo and Sargent are two of several massive sulphide prospects in a southern, 11-km-long linear belt of gossanous rhyolite volcanics. Field mapping along the belt has identified several new areas of base and precious metal mineralization associated with thickenings of the felsic volcanics.
These sulphide showings have been observed to occur at several stratigraphic levels.
Mapping and geochemical surveys are evaluating the numerous targets on a northern felsic-Volcanic belt. Drilling will begin in April at the Rio Hambre prospect, 18 km east-northeast of Arroyo Rojo. The program will test soil geochemical anomalies associated with disseminate-To-laminated pyrite and base metal sulphides in fragmental rhyolites of this northern belt.
The Fin del Mundo program, which includes seven Kuroko-Type
volcanogenic-massive-sulphide prospects northeast of the port of Ushuaia on the Beagle Channel, is operated by Vancouver-based Westmin, which is exploring Spokane, Wash.-based Yamana’s 193,000-ha land package. Westmin can earn a 50% interest by spending US$6.3 million over four years, and the company can increase this to 60% in any specific property by completing a bankable feasibility study. Westmin’s commitment for this field season, ending in June, is a US$1.8-million expenditure and 3,000 metres of drilling.
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