Bellhaven Copper & Gold Inc. reports the commencement of the previously announced ZTEM (airborne electro-magnetics) survey over the entire La Mina property (1,800 Ha). The survey is also being extended to include an adjacent concession, which the Company is currently in discussions to acquire. The work is contracted to Geotech Ltd., a Canadian geophysical survey company specializing in leading edge airborne technology. The survey is designed to help refine the targets at La Mina, with a particular emphasis on the Garrucha and Cristalina target areas.
The helicopter-borne geophysical survey will result in approximately 132 line kilometres of data along east-west lines, spaced at 200 metres. The Z-TEM Electromagnetic (EM) system is an innovative technique making use of naturally occurring or passive EM fields from worldwide thunderstorm activity as the source of transmitted energy. The passive source combined with a proprietary receiver design, advanced digital electronics, and signal processing results in low noise levels, exceptional resolution, and unparalleled depth penetration. It has been used successfully to identify and map porphyry style mineral systems from Alaska to Chile.
Patrick Highsmith, Bellhaven’s CEO, commented on the program: “We are pleased to bring the ZTEM technology to the Middle Cauca Belt for the first time. It is a proven technique for porphyries in the Americas. This will enable us to prioritize existing geochemical and magnetics anomalies, including on concessions that we are in negotiations to acquire. This is a very cost effective tool that adds immediate value in an emerging mineral district such as La Mina. By sharing the mobilization and some of the administrative costs with neighboring explorers, we have made it even more cost effective.”
Discussion of ZTEM Survey
The survey is expected to identify conductive and resistive features that are associated with large mineral systems such as gold-copper porphyries from surface to considerable depth. The electromagnetic data is sensitive to sulfide minerals, as well as silicification and clay alteration; all of which are associated with the porphyry and epithermal deposits in the Middle Cauca Belt. This will be an important addition to the magnetics data that drove the initial discoveries. The EM data will advance the geologists’ knowledge of the known resource areas, particularly at depth, but it will also upgrade the targeting arsenal elsewhere on the property. This work will also enhance understanding of large structures in the district. Many of these structures have previously been mapped from both surface exposures and drill intercepts; and the Bellhaven team is focused on their importance in controlling mineralization.
The survey crew arrived on site November 17, and began conducting reconnaissance flights a few days later. They are currently flying the survey as cloud cover permits. It is expected that a total of 6 to 8 days of favorable conditions is needed to complete data collection, so the survey should be completed before the end of December.
La Mina Porphyry Gold Copper Project
La Mina is a resource stage porphyry gold-copper project located in the Middle Cauca volcano-plutonic belt in the Department of Antioquia about 45 km southwest of Medellin. The Middle Cauca belt is known to host large porphyry gold deposits such as AngloGold’s La Colosa Deposit (24 Moz Au) and Sunward Resources’ Titiribi Project (11 Moz Au).
The La Mina concession includes almost 2,000 hectares. A number of anomalous features are evident from the initial airborne magnetic survey, completed by AngloGold. As surface sampling and drilling progressed, a number of multi-faceted targets emerged. Through the first half of 2012, a total of four known mineralized porphyry systems have been identified; two of these deposits are host to NI 43-101 compliant inferred mineral resources. The two remaining known porphyries will be the focus of future drilling, meant to advance these prospects to the resource stage as well. The exploration pipeline at La Mina includes a number of other targets that, based on geology, geochemistry and geophysics, have characteristics similar to porphyry or porphyry related deposits. There are at least 7 of these discrete targets undergoing additional work, but they have not yet been drilled. The figure below shows total magnetic intensity (reduced to pole) from an airborne magnetics survey. Many of the targets are identified on this map; and more detailed information is available below.