The subvolcanic True Hill granite porphyry in southwestern New Brunswick is genetically related to the Beech Hill series of granites of Devono-Carboniferous age. Three True Hill (TH) greisenised granite porphyry cupolas host Bi-Sn-Mo-W mineralized zones that have similarities to the nearby W-Mo-Bi orebodies at Mount Pleasant (MP).Tin-bearing lodes (0.03 to 0.66 wL % Sn) are developed along faults and fractures that cut both mineralized (Bi-Sn-Mo-W) and unmineralized True Hill granite porphyry and enclosing metasedimentary rocks of the Waweig Formation. Within these lodes, particularly the central Main lode, two types of mineralization are present, an early chlorite-sulfide assemblage (Stage 1) and a later hematite-phengite-cassiterite assemblage (Stage 2) that replaces, in part, the earlier Stage 1 assemblage. The Stage 1 assemblage consists of Fe-rich septechlorite, pyrite, low-Fe sphalerite, magnetite, chalcopyrite, galena, Pb-Bi sulfides, tennantite, arsenopyrite and native Ag. Fe-Mg-Mn metasomatism responsible for chloritization was coincident with leaching of alkali and alkali-earth elements during feldspar hydrolysis. The Stage 1 assemblage (chl-sulfide) was formed at low temperature (<200°C) and low oxygen fugacity. The Stage 2 assemblage includes hematite, phengite, cassiterite and monazite with minor late quartz and fluorite. This assemblage was deposited at slightly higher temperatures (200p-300pC), higher oxygen fugacity (above hematite-magnetite buffer) and at moderate pH 's (