Geology Of Sto. Tomas Ii Porphyry Copper Deposit
Redempta P. Baluda1 & Jocelyn B. Galapon2
1 Division Manager
Geology, Environment & Community Relations
Philex Mining Corporation
Padcal, Tuba, Benguet
2 Department Manager
Geology Department
Philex Mining Corporation
Padcal, Tuba, Benguet
Abstract
The Sto. Tomas II orebody is a copper porphyry type deposit being mined by Philex Mining Corporation in Tuba, Benguet for almost 47 years now. Since its discovery, a total of 294.0 million DMT of copper ore has been mined with average grade of 0.33%Cu and 0.60gAu/t. As of January 1, 2005 it has a remaining geologic resource of 118.0 million DMT with a grade of 0.26%Cu and 0.61gAu/t.
The deposit is located at the southern tip of the Baguio Mineral District. It was formed through a series of intrusions by a complex stock of quartz diorite porphyries into the Pugo-Zigzag Formation along a northeast trending fault. Fission Track Dating suggests that the mineralization was emplaced at about 3.0 my. The ore minerals are chalcopyrite and bornite associated with gold and silver. The alteration zones consist of potassic and propylitic. A pyrite halo is also present.
At present, the mine is developing the last and lowest mining level of the orebody which is 782ML. A wealth of information on the geology of the deposit has been accumulated. This report aims to present an update on the geology, alteration and mineralization of the Sto. Tomas II deposit. |