The Anagase "Kuroko-Type"
Deposits: A Case Of A Volcanogenic Massive Sulfide Discovery On
Samar Island, Philippines
a reconnaissance stream-sediment geochemical survey was carried-out
by Boliden AB Philippine Branch over about 500 square kilometers of
unexplored jungle territory in the Cretaceous volcanic-sedimentary
package in North-Central Samar region. This survey resulted in the
discovery of several volcanogenic massive sulfide occurrences in the
dacitic-andesitic volcanic units.
Anagase deposits which ranked as high priority targets for follow-up
surveys, were explored in detail by geologic mapping on outcrops,
trenches, test pits, shallow exploratory adits and crosscuts, plus
soil and bedrock geochemical sampling. Subsequent geophysical
surveys were carried out using Spontaneous Potential (SP), ground
magnetics, IP-resistivity, and Very Low Frequency (VLF) methods.
the encouraging surface geological criteria, supplemented by the
results of an integrated approach of geochemical and geophysical
techniques, the primary targets were drill-tested with 50 core holes
aggregating a total depth of 3,444.95 meters. The drilling results
yielded a resource of 1.3 million tons averaging 0.4% Cu, 3.7% Zn,
1.3 g/t Au, and 81 g/t Ag.
paper presents the various parameters employed leading to the
successful discovery and delineation of the Anagase "Kuroko-type"
deposits during the early stage exploration.