Ore Mineralogy and Geochemistry of the Phu Kham Porphyry Copper-Gold Deposit, Hosted within N-E Fault Zone, Lao PDR

Abstract

The Phu Kham “Mountain of Gold” copper - gold deposit is located in the Xaisomboun District in Vientiane Province in Lao PDR, approximately 100km northeast of the capital city of Vientiane. The mine is a major Cu-Au deposit which is located within the junction zone between the Loei and Truongson Fold Belts. These belts respectively from the west and northeast margins of the Khorat – Kontum, which comprises deformed Palaeozoic volcano - sedimentary sequences and associated with acid to intermediate intrusive rock, intermediate volcanic - clastics, interbedded Permo - Carboniferous limestones, red beds (basement rock) and schist host rock. In order to characterize the lithology, mineralogy and chemical composition of various material associated with the ore deposit and host rocks were conducted. Analytical techniques basically comprising petrological, mineralogical analyses (thin- and polished-sections), geochemical analyses as an X-Ray Diffraction and X-Ray Fluorescence (XRD and XRF) analyses were performed. Mineralization at Phu Kham mainly occurs within diorite bodies, intermediate porphyry dykes, mainly in schistose metasedimentary rock as well as a skarn bordering limestone. Most of the ore bearing minerals within the Phu Kham deposit comprise predominantly pyrite, chalcopyrite, bornite, arsenopyrite, galena, sphalerite.Mineralization mainly occupying and hosted within N-S trust fault hanging wall associated with schist, diorite bodies, intermediate porphyry dykes, breccia, schist as well as a skarn bordering limestone.