Briefing at the Hatchobaru Geothermal Power Plant   -   with Professor Taguchi of Fukuoka University, Japan who travelled with the group as technical leader of the tour in Japan.

Professor Taguchi (right) explains the geology and alteration zoning, and the associated, temperature and pressure conditions.   Low sulphidation gold mineralisation is currently being precipitated in the pipe scale from neutral steam heated waters used to generate geothermal power.   Scale from the pipes carrying more than 5 g/t Au is shown below.   The pipe has a diameter of ~60 cm.   Following the presentation the group visited the Komatsu-jigoku steaming ground 300 m to the northeast where the alteration zoning could be seen at surface.
Photographs by Mike Porter.