Gallium occurs at above background levels in most samples collected from 11 of the major geothermal areas in the Taupo
Volcanic Zone. Concentrations of Ga in the 48 samples ranged from 8 to 144 mg kg-' and varies widely from place to
place within each geothermal area. Gallium is contained within the alumino-silicate structure of clay in the mud, having
substituted mainly for Al. Suggested deposition mechanisms for Ga also involve co-precipitation with Sb, As, and SiO.
colloids. Digestion trials, carried out to determine extraction conditions for possible commercial exploitation, showed
that heating the mud to 500 -600C for 1 hour followed by acid/alkali treatment gave complete recoveries.