2022 Volume 72 Issue 1 Pages 1-12
Silicified ore, used for flux at the copper smelters in Japan, often contains gold(Au). Today, only a few mines in Japan produce and sell Au-bearing silicified ore to copper smelters, and their importance are becoming increasing. The Iwado mine, one of the few mines, is the high-sulfidation type deposit located in the Nansatsu district, southwestern Kagoshima prefecture. Although it is known that the silicified rocks occurred in the Iwado-yama area at the western end of the Iwado mine, its potential(volume and Au grade) has not been evaluated quantitively due to lack of exploration data both in quality and in quantity. JX Nippon Mining & Metals Corp. carried out geological, geochemical and electrical resistivity surveys for revealing the silicified ore extent in the Iwado-yama area. The results showed that the ore body is distributed in a northeast-southwest direction along the Iwado-yama mountain ridge and thinner toward the southwest. Geochemical survey showed the silicified rocks in this area could serve as flux for smelters, and in terms of Au the historical drilling information encourages further exploration activities. In order to outline the ore body and to estimate Au content, further drilling surveys should be conducted, and hopefully result in additional ore reserves for the Iwado mine.
