Mineral deposits in Ecuador are many but only one metalliferous mine, the Portovelo gold mine, now is operating. It was worked in colonial times but on a systematic basis only since 1904. Gold was the principal product together with silver, copper, lead, and zinc. At present, copper is more important but the ore reserves are virtually exhausted. The Macuchi mine was worked for copper, gold, and silver in the 1940s and prospects containing various combinations of copper, silver, lead, and zinc were discovered at La Plata, Sigchos, Molleturo, and Pilshum.

In 1965 the United Nations in cooperation with the newly established Servicio Nacional de Geologia y Mineria began a seven-year mineral resources survey. The principal discovery was the Chaucha porphyry copper-molybdenum deposit where 55 million tons of 0.7-percent copper were proved. Other porphyry copper-molybdenum deposits were discovered at Los Linderos, Rio Playas, and Fierro Urco. At Fierro Urco 50 million tons of ore with low-gold values was indicated. Vein-type mineralization at Angas (copper, lead, zinc, silver, and gold), San Bartolome (silver and lead), and Uritohuaser (zinc, lead, and silver) also were discovered. Anomalies in tin and tungsten minerals were found near Saraguro.

Most surveys have been in the southern Andes where exposed Tertiary and older rocks are intruded by granitic bodies. The flanks of the Andes have not been explored thoroughly because of difficult access and dense forest. Much of the north-central Andes has a cover of Quaternary volcanic rocks mantling the older rocks, but until there are methods to probe through this thick mantle for possible mineralization the potential is unknown. The prospects however must be good because the Ecuadorian Sierra is part of the great mineralized mountain belt extending through the western Americas.

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