Epithermal Au-Ag deposits are found around the Pacific rim, and these important resources of precious metals represent small-scale features that form at shallow depths (<1 km,><300c) in large-scale hydrothermal systems associated with volcanism. ore bodies are localized in zones of strong paleo-permeability commonly controlled by subvertical extensional structures where very strong fluxes of boiling fluid develop episodically. the mineralogical products of boiling, comprising ore-grade mineralisation, distinct vein textures, and zoned hydrothermal alteration, have been used to interpret mineralizing conditions in prospects and deposits for several decades. given that precious metal mineralisation is commonly blind to the surface, this type of analysis is especially useful in regard to assessing discovery potential, proximity to ore bodies, and the depth level of exposure, even in mature districts with long histories of exploration and mining. an up to date understanding of boiling processes and their mineralogical-geological effects are described below based on investigations of active epithermal environments. descriptions of the patterns of alteration and mineralization observed in four major vein districts (fruta del norte, cerro negro, fresnillo, waihi-favona) follow to show the range in size, geometry and expression of boiling zones in epithermal deposits. these illustrate how and where key indicators of boiling can be used in finding new ore bodies (figures 1 and 2). citation: simmons, s f, 2019. boiling zones and precious metal mineralisation in epithermal environments, in proceedings pacrim 2019, pp 5152 (the australasian institute of mining and metallurgy: melbourne).>