Andina Copper Corporation (TSX-V: ANDC | FSE: FIR | OTCQB: PMMCF) has reported an outstanding drill intercept from hole CDH005 at its Cobrasco Project in Choco, Colombia. The hole was designed to test the southern extensions of the Cobrasco system to a depth of 700 meters, in a large step-out over an area of limited geological data and no prior drilling.
CDH005 confirms a large-scale southerly extension of copper-molybdenum-silver mineralization, demonstrating a large multi-phase porphyry Cu-Mo system with newly observed intermediate intrusive phases consistently mineralized over broad intervals. The results significantly extend the mineralized envelope to the south, with the potential for a globally significant copper deposit(s) at Cobrasco.
Drilling thus far has tested an area of approximately 1000 meters by 750 meters, less than half the potential footprint of the 2500-meter by 1000-meter target area. Systematic drilling is ongoing, with step-out drillholes CDH006 and CDH007 completed (assays pending) and new drillhole CDH008 underway targeting the northern extension of mineralization.
Andina Copper’s President and CEO Joseph van den Elsen commented: “Ongoing drilling at Cobrasco continues to demonstrate the large-scale and relatively shallow nature of Cobrasco Central, with results from hole CDH005 significantly extending the mineralized envelope to the south. With broad spaced holes having tested less than half the target area to-date, we see the potential for a globally significant copper deposit(s) at Cobrasco. To accelerate exploration and evaluation, a second drill will be mobilized to systematically explore and define the lateral extents of the Cu-Mo system and to add volume to the higher-grade copper shells intersected in drilling to date.”
Unlike earlier holes which intersected a multi-phase quartz-rich rhyolitic to dacitic subvolcanic dome complex, hole CDH005 is characterized by mineralized diorite to dacite-andesite porphyries, generally manifesting as magnetic intrusive sequences at surface transitioning to a magnetic low “embayment” at depth. The intermediate dacite-andesite units are intruded by several narrow quartz-rich felsic rhyolite subvolcanic intrusions.
Hole CDH005 was collared within dark-colored diorite porphyry units and remained within this phase to approximately 170 meters downhole before intersecting fine-grained dacite–andesite units. These subvolcanic porphyries exhibit visually significant chalcopyrite-dominant sulphide mineralization, accompanied by weak to moderate sericite alteration overprinting earlier potassic assemblages.
The dacite–andesite units are intruded by thin apophyses of intermineral rhyolite porphyry and extend to approximately 630 meters downhole, where the hole intersected a younger and lower-grade intermineral rhyolite porphyry that continues to end of hole at 934 meters. The lower sections of CDH005 display epidote–chlorite alteration consistent with a propylitic assemblage, interpreted to represent the outer or lower zones of the Cobrasco hydrothermal system. The mineralization remains open to the south.
The continuity of intrusive phases, alteration styles and sulphide mineralization throughout the drillhole is supported by wide intercepts of moderate to high grade copper mineralization interpreted to be predominantly associated with the waning stages of potassic alteration transitioning into early sericitic alteration. Assay results support the interpretation of a large and long-lived mineralizing system extending south of the currently defined Cobrasco footprint.
The large, strongly coincident copper-molybdenum surface geochemical anomaly currently being tested by drilling extends approximately 2.5 kilometers north–south and 900 meters east–west. A systematic environmental baseline program has commenced across the project area.
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