CHARACTERISTICS OF VEIN RELATED TO HIGH GRADE GOLD MINERALIZATION FROM EASTERN A PIT OF THE CHATREE GOLD DEPOSIT, CHANGWAT PHICHIT AND PHETCHABUN, THAILAND

Abstract

Chatree gold mine is the largest gold-silver epithermal deposit in Thailand. This deposit is characterized by quartz-carbonate-chlorite-adularia-pyrite veins and breccias vein cross-cutting into volcaniclastic sedimentary rock and andesitic volcanic breccia. Several mining pits have been operated at the Chatree deposit. This study area is focused on the Eastern A pit which is located in the northern part of the deposit in which gold mainly occurs in quartz veins and hydrothermal breccias hosted by volcanogenic sedimentary rock. High grade gold veins were investigated in mineralogical characteristics related to the main gold mineralization, particularly in the second stage vein of quartz-carbonate-pyrite (sulfide-base metal) band or stockwork. Based on quartz textural and petrological analyses gold and electrum usually form as fine inclusions significantly in pyrite host. Moreover, adularia may occur with gold forming multiple-phase inclusions in pyrite host. Geochemical investigation indicates that high grade vein samples are related to higher Te content and Te appears to enrich in electrum grains. Various textures of quartz in these veins were recognized includes band, plumose, comb-zonal, moss, ghost-sphere and saccharoidal texture. Among them, banded and plumose quartz textures appear to be closely associated with high grade gold and both textures are mostly common found in vein samples under this studies. The significant pattern of trace elements in probability diagram were determined for possible pathfinder of gold which they are Ag, As, Cu, Pb, Zn, Sb and Te. In addition, box diagram of trace elements was correlated with quartz texture and sulfide assemblage in the main gold mineralized vein; consequently, the significant pathfinder of gold deposit were indicated including Au, Ag, Te and Zn.