Philippine Association of Geology Students –

Society of Economic Geologists Student Chapter

Field Trip Report

Overview

The Philippine Association of Geology Students, the student chapter of the Society of

Economic Geologists organized a mine tour of the epithermal deposit in the mining tenement of

theItogon – Suyoc Resources Inc. (ISRI). The mine tour was carried out last July 1, 2017 in

Itogon, Benguet, Philippines. Twelve undergraduate and five graduatestudent chapter members

from Adamson University, Mapua University and University of the Philippines joined this

activity. The field trip began with an introductory lecture given by Dr. Karlo L. Queaño, ISRI

Supervising Senior Geologist, on the geology of the Baguio Gold District, one of the more

prolific mineral districts in the Philippines. The PAGSmembers were given an overview of the

Sangilo gold mineralization style and to recognize features related to an epithermal deposit. This

field trip was arranged by Dr. Carla B. Dimalanta, PAGS Faculty Advisor and head of the

Rushurgent Working Group of the University of the Philippines – National Institute of

Geological Sciences in coordination with ISRI.

Introduction

Mineralization in the Philippine archipelago is attributed to its complex geologic and

tectonic setting. This resulted to the formation of six major gold-producing districts, namely the

Baguio and Paracale Gold Districts in Luzon, the Masbate Gold District in Central Visayas, the

Surigao and Masara Gold Districts in Eastern Mindanao, and the Zamboanga Gold District in

Western Mindanao (Mitchell and Leach, 1991; Yumul et al., 2008). Among these areas, the

Baguio Gold District is known as a world-class mining district that supplies the majority of gold

and copper resources in the country (Yumul et al., 2008). In the lecture given by Dr. Queaño, he

explained that mineralization in the Baguio Gold District is possibly related with the flat slab

subduction of the South China Sea crust along the Manila Trench. The Baguio Gold District is

also host to several world-class deposits, such as the Santo Tomas porphyry copper deposit and

the Acupan and Antamok epithermal deposits (Garwin et al., 2005).

In this mine tour, the student chapter members visited the Itogon-Suyoc Resources Inc.

mine site in Sangilo, Itogon, Benguet. The discussion about the Sangilo epithermal gold deposit

was led by Dr. Karlo Queaño, along with Dr. Eric Andal (Assistant Vice President for

Operations and Geology, ISRI) and Mr. Arvin Trinidad (Geologist, ISRI).

Mine Tour Proper

The mine tour at ISRI followed the itinerary as shown below.

Schedule Details

7:00 – 8:30 Travel from Baguio City to Sangilo

8:30 – 9:00 Orientation and safety seminar

9:00 – 12:00 Underground mine tour at ISRI

12:00 – 13:00 Lunch

13:00 – 14:00 Travel from ISRI to Dalupirip Schist

14:00 – 14:30 Lecture about Dalupirip Schist

14:30 – 20:30 Travel from Sangilo to Manila

Before getting to the mine site, the group stopped in the Virac area where Dr. Queaño

pointed out the Balatoc Plug. The Balatoc Plug is a diatreme breccia in Acupan, Benguet which

is considered as the igneous body responsible for the epithermal mineralization in the Atok,

Ampucao, Acupan and Sangilo epithermal deposits. Mineralization in the Balatoc Plug is mostly

concentrated along its contact with the Central Cordillera Diorite Complex.

Dr. Queaño (in blue) giving his preliminary lecture about the role of the Balatoc Plug on the

mineralization of the Acupan-Sangilo epithermal deposits.

Mineralization in the Sangilo deposit is hosted in the Central Cordillera Diorite Complex.

The area’s mineralization is classified as an intermediate epithermal sulfidation type. Its main

gold-producing veins are the E-W trending Taka Barr and Cotcot veins and the NE-trending Frog

vein. The vein systems in the area are all structurally-controlled, with the E-W trending veins

acting as extensional jogs to the bounding right-lateral NE-trending faults which include the Frog

vein.

Dr. Queaño explaining the orientation and spatial relationship of the veins in the Sangilo deposit

using 3D stack models.

The group visited tunnels in ISRI to examine underground exposures of the Taka Barr

vein. At the Level 0 Tunnel, the Takka Bar vein is composed of quartz and calcite with banded

and crustiform texture andminor disseminated sulfides such as pyrite, chalcopyrite, sphalerite

and galena. At Level 0 Raise 25 6th Floor, the quartz-calcite vein is bordered by argillized

diorite. The vein has an attitude of N75°E, 60°SE. Manganese concentrations are also notable in

this exposure. Aside from veins, the cross-cutting relationships of the different rock units and

structures were also examined underground.

Members of the SEG Student Chapter visited operating tunnels in the mining tenement of

Itogon-Suyoc Resources Inc. (ISRI) to access the gold producing veins in the Sangilo epithermal

deposit.

An underground exposure of the Takka Bar vein at Level 0 Raise 25 6th Floor which is bordered

by argillized diorite host rocks. Manganese concentrations on the argillized diorite are also

evident in this exposure.

A sample obtained from the Takka Bar vein at Level 0 Raise 25 6th Floor composed of quartz

and calcite with banded crustiform texture and disseminated sulfides. Manganese stains are also

notable in this exposure.

An intrusive contact between the diorite host rocks and the younger andesite unit of the Central

Cordillera Diorite Complex.

After visiting the underground tunnels, the student chapter members were also given a

tour of the mine’s assay laboratory where the metal grade of the recovered ores are determined.

A stop was also done at the mine’s mill site where the students were provided an overview on

how the collected ores are crushed, milled and processed for its gold content. After the ore

blocks from the producing tunnels are turned to powder through multiple steps of crushing and

milling, they will then be sent to a Carbon-in-Leach tank to liberate the gold.

Members of the student chapter also visited the type locality of the Dalupirip Schist in

Agno River, Itogon, Benguetafter the mine visit at ISRI. The Dalupirip Schist is recognizable by

its distinct greenschist facies metamorphism. Its protolith is believed to be the Pugo Formation.

Its distribution is localized in a narrow zone near contacts with quartz diorite units especially in

the Itogon Area.

Members of the SEG Student Chapter were shown how the metal assays of vein samples are

done in the Assay Laboratory of the Itogon-Suyoc Resources Inc.

Members of the SEG Student Chapter visited the type locality outcrop of the Dalupirip Schist in

Itogon, Benguet with Dr. Karlo Queaño and Mr. Arvin Trinidad of the Itogon-Suyoc Resources

Inc.

Financial Report

Particulars Cost

Bus Fare (Manila-Baguio, 14 pax) 5,000.00

Van Rental (Baguio-Sangilo; 2 vans) 7,000.00

Van Rental (Baguio-Manila; 2 Vans) 13,000.00

Total 25,000.00

2017 Hunt for Ore Deposits:

Challenges and Opportunities for Environmental Sustainability

Before the mine visit, the student chapter members participated in the international

conference entitled, “2017 Hunt for Ore Deposits: Challenges and Opportunities for

Environmental Sustainability” at the Venus Parkview Hotel in Baguio City on June 29-30,

2017. The participants were given a chance to acquire more knowledge by listening to the

presentations made onmineralization, economic valuation of mineral deposits, as well as

phytoremediation techniques to address environmental concerns. Researches of some graduate

and undergraduate student chapter members were also presented as oral and poster presentations

during the conference.

Members of the SEG Student Chapter from Adamson University, Mapua University and

University of the Philippines were among the participants in the 2017 Hunt for Ore Deposits:

Challenges and Opportunities for Environmental Sustainability last June 29-30, 2017 in Baguio

City. Included in the picture are (topmost, from left to right) Dr. Jillian Aira Gabo-Ratio, Dr.

Betchaida Payot, Dr. Carla Dimalanta (Faculty Advisor), Dr. Keiko Hattori, Dr. Graciano Yumul

Jr. (Industry Advisor), Dr. Jeffrey Hedenquist and Dr. Victor Maglambayan.

Members of the PAGS-SEGSC with the organizing committee of the 2017 Hunt for Ore

Deposits conference.

Acknowledgements

The Philippine Association of Geology Students – Society of Economic Geologists

Student Chapter would like to acknowledge the support provided by the Society of Economic

Geologists through the Stewart R. Wallace Fund.

We would also like to express our gratitude to the Itogon-Suyoc Resources Inc. for

accommodating the PAGS-SEGSC in the mine visit and providing the students an opportunity to

experience underground mining, most especiallyto Dr. Karlo Queaño, Dr. Eric Andal, and Mr.

Arvin Trinidad for sharing their knowledge and expertise by providing lectures on the geology

and mineralization of the Baguio District and of the Sangilo epithermal gold deposit.

The organization would also like to extend their heartfelt thanks to the Rushurgent

Working Group, to Dr. Graciano P. Yumul Jr. and Dr. Carla B. Dimalanta, PAGS industry and

academic advisors, for helping facilitate these activities.

References:

Garwin, S., Hall, R., Watanabe, Y. (2005). Tectonic setting, geology, and gold and copper

mineralization in Cenozoic magmatic arcs of Southeast Asia and the West Pacific.

Economic Geology 100th Anniversary Volume, pp. 891-930.

Mitchell, A.H.G., Leach, T.M. (1991). Epithermal gold in the Philippines: island arc

metallogenesis, geothermal systems and geology. Academic Press, London, 457 p.

Yumul, G.P. Jr., Dimalanta, C.B., Maglambayan, V.B. (2008). Tectonic setting of a composite

terrane: a review of the Philippine island arc system. Geosciences Journal 12 (1), pp. 7-

17.