Del Carmen Geophysics
In order to identify new drill targets, a 40 line-kilometre Titan 24 IP/Resistivity (DCIP) survey is underway at Del Carmen Norte. The Titan 24 method was selected due to the greater depth of surveying than conventional IP methods (generally limited to 200-250 m depths) given that recent drilling at Rojo Grande has encountered deeper mineralization. The small IP/Resistivity survey completed by Barrick Gold in the mid 1990s focussed on Rojo Grande and reprocessing of the data identified a distinct pattern of high resistivity and low chargeability is associated with oxidized gold-silver mineralisation hosted by silicified rocks at Rojo Grande. The Titan 24 survey will be conducted on 200 m spaced lines across the entire 9 km2 Del Carmen Norte alteration system, and will allow detailed three-dimensional modelling of the subsurface conditions beneath the Del Carmen Norte alteration system that will be constrained by our previous and ongoing diamond drilling. The results generated by the survey will allow us to drill test new targets during the current field season.
During the fourth quarter of 2010, we released results of two geophysical surveys (magnetometer and controlled source audiomagnetotelluric -CSAMT) completed at Del Carmen Norte. The CSAMT survey identified extensive zones of elevated resistivity, which are typically associated with hydrothermal silicification. Zones of silicification are the principal host of gold-silver mineralization in high-sulphidation epithermal deposits.
Highlights from the surveys at Del Carmen Norte are:
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CSAMT resistivity anomalies including:
- One that is coincident with outcropping and subsurface silicification that hosts gold-silver mineralization at Rojo Grande;
- Several broad (up to 1,200 metres) correlative anomalies on successive survey lines for over 1,000 metres southwest of the Rojo Grande zone of silicification to Cerro Amarillo and to the vertical extent of the survey methodology (about 500 metres); and
- Multi-line subsurface anomalies beneath Quebrada Pedregosa and Quebrada Del Medio (Figure 4) that flank the central massif of alteration.
- An asymmetric magnetic low (2km x 3km) in the core of the altered area, which hosts the prospective Rojo Grande and Naciente Quebrada Pedregosa targets. Magnetic lows are conventionally interpreted to reflect magnetite destruction by intense hydrothermal alteration of volcanic and intrusive rocks.
See geophysical figures or full report in Spanish for details
Plans for the 2011/2012 season include 40 line - Km of IP/Resistivity surveying to identify new drill targets.
