Geology and Ore Deposit of the Santo Tomas Mine, Philippines

Abstract

Exploration of the Santo Tomas copper deposit has been conducted by the Philex Mining Corporation since 1955. The mine now produces about 100, 000 metric tons of crude ore per month on an average, which is equivalent to approximately 2, 500 metric tons of copper concentrates. The mine is located at about 20km south of Baguio City, Mt. Province, Philippines. Ore deposit of the mine is a low grade gold-bearing copper ore deposit belonging to the so-called "porphyry copper". The huge ore body is made up of numerous. scattered veinlets and impregnation of quartz, Pyritc chalcopyrite, magnetite and other minerals.
The mineralization has been developed principally in the meta-volcanics of Jurassic age, and extended over a short distance to the diorite-porphyry of Late Cretaceous. The fracture pattern of these veinlets is mainly controlled by the effect of diorite-porphyry intrusion in the fractured zone along the direction of off-shoot of the Agno diorite batholith.