“…The occurrence of selenides has been reported from four major types of hydrothermal deposits: "telethermal" selenide vein-type deposits, unconformity-related deposits, sandstone-hosted uranium deposits, and epithermal Au-Ag deposits in subaerial volcanic environments (Simon et al, 1997). As reported in the literature worldwide, hydrothermal gold deposits containing selenides are mostly restricted to epithermal Au-Ag deposits that are genetically related to continental volcanism, for instance, the Koryu (Shimizu et al, 1998), Kushikino (Mukaiyama and Izawa, 1964;Shikazono et al, 1990), Hishkari (Izawa et al, 1990;Shikazono et al, 1990), Chitose, and Yatani mines (Shikazono et al, 1990) of Japan; the Sleeper (Saunders et al, 1988;Saunders, 1993) and Jarbridge mines (Hewitt, 1968) of Nevada, the Silver City mine Ramdohr, 1980) of Idaho, and the Republic mine (Full and Grantham, 1968) of Washington, all in the United States; the Torquay mine (Paar et al, 1998) of England; the Great Barrier Island (Ramsay and Kobe, 1974) and Camoola mines (Main et al, 1972) of New Zealand; the Salida (Kieft and Oen, 1973) and Redzhang Lebong (Sindeeva, 1964) mines of Indonesia; the Guanajuato mine of Mexico; the Providencia mine (Paniuga, 1995) of Spain; as well as many Au-Ag deposits in the Circum-Pacific and Mediterranean metallogenic belts, such as the Prasolovskoye, Kunashir Island, and Kuril Island deposits (Nekrasov and Lunin, 1987;So et al, 1995), all of which can be taken as the typical examples. Nevertheless, those ore depos its bear no Se-rich mineralized bodies, although the concentrations of Se are somewhat elevated.…”