20 - 100 million tonne IOCG type oxide Cu-Au deposit
200 - 300 million tonne porphyry Cu-Au deposit
The 100% owned 4,500 hectare Sierra Pintada property is located in the Chilean Coastal copper-gold belt 650 kilometers north of Santiago.The property is readily accessible from the town of Vallenar 30 km to the east. The property covers a 15 kilometer strike length of the Atacama Fault system. The individual structures that form the Atacama Structural zone in this sector are the loci of numerous centers of past high grade copper, gold, silver and cobalt mining e.g. Carrizal Alto District passed production approximately 450,000 tonnes of copper and 1.5 million ounces of gold.
The Company’s prior exploration programs on the Sierra Pintada identified two strong copper and gold-bearing mineralised structures,Viña (pronounced Vee-nia) and Gloria, each at least 15 kilometres in length and 50 to 200 metres in width. Wherever these structures emerge from beneath overburden they are the centers of numerous prospect pits, adits and shafts to depth of 50 metres on high grade Cu-Au (Ag,+/-Co) and Au-Cu (Ag) fissure veins from 1-5 metres in width.
3D IP Survey
In 2007-08 the company performed a deep-penetration 3D Induced Polarization (IP) geophysical survey to test the known high-grade structurally controlled gold and copper showings on the property for potential deeper porphyry bulk-tonnage or iron-oxide-copper-gold targets. The survey covered the Viña, Gloria and Totora Zones and outlined several high priority IP targets including a strong IP target in an unexplored area just to the south of the Vina Zone. Recent field follow-up of this target resulted in the discovery of a mineralized Au+Cu bearing highly silicified brecciated quartz porphyry dyke. This new zone is now referred to as the Futura Zone.
The discovery of a new Au-Cu bearing mineralized silicified brecciated quartz porphyry dyke coincident with a strong IP target greater than 1 km long is now considered the highest priority target on the Sierra Pintada property.
During a 2009 field evaluation, a silicified brecciated quartz porphyry dyke with up to 30% fine disseminated pyrite running up to 0.685 g/t Au, 6.2 g/t Ag and 0.0365%Cu was discovered directly above the strongest part of the IP target. The IP response suggests that this mineralized Au-Cu bearing porphyry extends north-northeast for over 1 kilometer and is open to the south-southwest possibly outlining a large Au-Cu rich porphyry system in this area.
The IP geophysical survey also outlined a buried unexplained 1.2 kilometer long IP targetcoincident with a 500 meter wide resistivity-low trend striking northeast through the Gloria Zone. This resistivity-low is coincident with part of the main northeast trending Atacama fault system known to host most of the Au bearing zones on the Sierra Pintada property. The IP target is also thought to outline a buried mineralized porphyry system similar to the mineralized porphyry recently discovered in the Fortuna Zone.
In the Tortora Zone (southern extension of the Gloria Zone) a 500m long by 300m deep resistivity low anomaly occurs coincident with a gold bearing alteration zone. Recent samples taken from the open cut and from stockpiles returned anomalous Au-Ag with grades of up to 7.86 g/t Au and 7.4 g/t Ag. Several other samples were taken from much smaller hand worked open cuts approximately 2 kms to the northeast along strike from the area of active workings and returned high grade values of up to 17.35 g/t Au and 1.8 g/t Ag.
Based on the outline of the resistivity-low anomaly associated with the alteration zone, this area is thought to have the size potential to host a shallow bulk tonnage high grade Au deposit.
Viña Zone (see Gloria Zone IP results)
Numerous old trenches, adits and open cuts from 1-10 metres wide, with conspicuous green oxide copper minerals, are present throughout this sector. 2004 chip sampling results ranged from 0.2% to 8.0% copper and 0.1 g/t and 2.5 g/t gold over 1-5 metre widths. (PBX NR July 30, 2004)
The geophysical survey over the Viña Zone identified a series of weaker IP targets coincident with the historic Au-Cu workings. These weaker IP targets are unexplained, but the geology and Au-Cu mineralization suggests that the area also has potential to host an IOCG or porphyry Cu-Au system at depth.
©2009 International PBX Ventures Ltd.