The Ladolam gold deposit, located on Lihir Island in PNG, is one of the largest known epithermal gold deposits, with a resource of over 37 million ounces. The deposit is characterised by a telescoped porphyry-epithermal system <0.5 million years in age, hosted in the brecciated core of a volcanic crater partially encroached by the sea. three stages of mineralization are recognised, the oldest being a low-grade cu-au-mo porphyry (stage i). the main mineralization at the minifie area, which is currently being mined, formed during the transition from the porphyry to epithermal environments (stage ii). minifie ores are characterised by pervasive adularia alteration and refractory pyrite mineralization within extensive shallow hydrothermal breccias, located above biotite-altered porphyritic stocks. later quartz-calcite-adularia stockwork veins, typical of low sulphidation systems (stage iii), form ores at the lienetz area. some important factors that contributed to the formation of the deposit include the oxidised alkaline composition of the magmas, favourable co2-rich sulphidic hydrothermal fluids capable of transporting significant quantities of gold, and the sudden change from porphyry to pithermal conditions caused by removal of the volcanic edifice. as magmatic ore fluids breached the surface, cool surface waters (seawater and or meteoric) acted as a diluent. although no other deposit is known with comparable geological characteristics and size, positive features that may be looked for in exploration for other like-deposits elsewhere include magnetite-rich alkalic volcanic rocks, large carbonate haloes, and presence of phreatomagmatic breccias. new discoveries may be recessive or undercover, due to the quartz-poor nature of the alteration.>