HEAT AND GOLD EXPLORATION ON FIJI ISLANDS

Abstract

In this study we present an exploratory study of the relation of gold in mineralized waters and the possible use of geothermal power. The Vautakola gold mine in northern Viti Levu features a high geothermal activity in and outside of the mine site itself. Temperature in the 900m deep underground mine are around 60º C and the water is of magmatic origin. Ongoing investigations of the mineral content in the mine water suggest that high levels of dissolved gold can be found.
A parallel study on the adjacent island Vanua Levu already has revealed 0.77 ppb Au at surface water derived from a magmatic intrusion in Tabia, North Vanua Levu. This value is about 100 time higher than normal seawater and higher gold content can be expected at depth due to higher solubility at higher temperatures.
The hot springs on both islands are of intermediate to high temperature in the 60-100º C bracket. Investigations are under way to win electricity from the hottest location in Savusavu (South Vanua Levu) and Waiqele (North Vanua Levu). Aside from electricity generation the temperature of the surface springs is sufficient for direct heat use such as food drying, refrigeration and desalination. The latter technology is of particular interest to the potential harvesting of gold from these mineralized waters and a suitable Multi-Effect-Distillation is presented in our companion presentation on mineral extraction by MED desalination technique (Chua and Regenauer-Lieb, 2018).