Andina Copper Corp. has reported a wide intercept of copper-gold-silver mineralization at its Piuquenes East project that significantly expands the vertical extent of the mineralized envelope and confirms increasing gold grades and intensity of porphyry stockwork veining laterally and to depth. Drill hole PIU09, only the third drilled at Piuquenes East, intersected a broad, continuous interval of copper-gold mineralization hosted within strongly veined, dioritic porphyry with intense sericitic alteration overprinting potassic, confirming the presence of a new vertically extensive gold-rich porphyry Cu-Au-Ag system within the Piuquenes-Altar cluster.
The drill results show PIU09 intersected 126 meters at 0.46% copper, 0.53 grams per tonne gold, and 2.14 grams per tonne silver from 529 meters depth, within a broader interval of 402 meters at 0.25% copper, 0.21 grams per tonne gold, and 1.19 grams per tonne silver from 253 meters. The mineralization features well-developed A-type veins coincident with chalcopyrite ± bornite mineralization, with higher gold grades and increasing intensity of A and B-type veining observed at depth, consistent with proximity to the porphyry core. Bornite-rich potassic alteration with higher gold grades may be preserved beneath the sericitic overprint.
Follow-up drilling is underway to evaluate the northern continuity of the Cu-Au mineralized porphyry system at Piuquenes East. The deeper mineralized interval is hosted within crowded dioritic porphyry exhibiting well-developed sericitic alteration overprinting potassic represented by intense chalcopyrite-bearing A > B veins. Veining intensity increases downhole, with moderate to strong quartz-sulphide stockwork development locally reaching 40-60 veinlets per meter. Hydrothermal magmatic breccias are developed along intrusive contacts laterally to the mineralized zone.
Intense sericitic alteration overprinting potassic assemblages indicates the system underwent substantial telescoping, suggesting potential for a potassic gold-rich core at deeper levels. Follow-up hole PIU11 is designed to test the northern continuity of the Cu-Au-Ag mineralized porphyry system and evaluate the lateral and vertical extent of the mineralized corridor identified to date. The hole has been positioned to intersect a geophysical chargeability anomaly defined by Induced Polarization surveying and a coincident conductive feature identified in Magnetotelluric data.
A second drill rig has commenced testing a strong, coherent, deep-seated, low-resistivity anomaly at Piuquenes North identified by the recently completed MT geophysical Survey. The anomaly is characterized by its low-resistivity contrast, significant vertical extent commencing approximately 600 meters below surface and extending well below the limits of current drilling beneath the known mineralized centres at Piuquenes East and Piuquenes Central. In the context of Miocene-aged porphyry systems of the southern Andes, conductive features of this scale and depth are commonly associated with deep intrusive activity or magmatic-hydrothermal sources, rather than shallow alteration effects.
Integration of the MT data with existing Induced Polarization datasets, drilling results, alteration mapping and structural interpretation has improved understanding of the spatial relationship between deeper conductive features and overlying porphyry-style mineralization. This relationship suggests that the currently defined Piuquenes East and Central mineralization may represent upper-level expressions related to a deeper source at Piuquenes North. The MT anomaly will be tested by the PIU12 drill hole and PN02, designed to test this feature and its interpreted relationship to known mineralization.
