DISCOVERY HISTORY OF THE PORPHYRY COPPER-MOLYBDENUM DEPOSIT AT SIERRA GORDA, ANTOFAGASTA PROVINCE, CHILE: IMPLICATIONS FOR SUCCESSFUL EXPLORATION IN MATURE TERRANES
Notable factors at SG included: 1) A large, well organized data base, preserved core, and well studied regional geology all aided recognition of the porphyry system. 2) Classical porphyry Cu geology – mapping veins, alteration and sulfide mineralogy - delineated the system and the deposit. 3) A geologic team with broad experience in Chile and porphyries worldwide had the ability and authority to make independent decisions and change program plans on the fly. 4) Aggressive drilling and quick follow up speeded evaluation. 5) Regional geophysics played no part; but project IP and mag helped illuminate geology. 5) Knowledgeable, supportive and decisive senior management acquired the original project; accepted the rationale to explore the larger system; and made a strong financial commitment to reinforce success. 6) Luck - the project contained an ore deposit; and acquisition, discovery and definition all took place in a long “bull” copper market.
Mature terranes are the future of exploration. The SG discovery was driven by a creative synthesis of regional, district and project data; the process was much more like brownfields than frontier exploration.