Cluster of porphyry copper-gold prospects. Artisinal mining of high-grade copper ore from six shafts and tunnels. Multiphase syenite, quartz monzonite. Monzodiorite, diorite intrusions as dikes, sills, and small stocks intruding ultramafic rocks. Potassic, phyllic alteration. Intersections of Philippine Fault splays and cross-cutting faults. Epithermal gold mined at American Tunnels; younger epithermal gold cuts older porphyry-related alteration. Late phyllic and skarn overprint early potassic alteration. Note that there is an Agata nickel laterite deposit nearby.