Microtremor Survey for Exploration Targetting Epithermal Vein Systems at the Hishikari Gold Mine, Kagoshima, Japan

Abstract

Summary This paper discusses applicability of the microtremor survey to the complicated structure in mineral exploration, taking epithermal vein systems as an example through a case study at the Hishikari mine, the largest and richest gold deposit in Japan. In general, epithermal gold deposit itself is relatively difficult target for geophysical exploration. Almost all geophysical techniques are deployed aiming at detection of some physical phenomena associated to mineralization, e.g. basement highs and hydrothermal alteration. The experimental microtremor survey in this study showed wide-range applicability to the exploration of epithermal gold deposits, especially the possibility to detect vein systems more directly through the higher modes in the dispersion curves. Although microtremor survey is still in the research and development phase, and even in the particular case of this study, quantitative analysis of the elastic characteristics of the ore body and its circumference needs further validation in practice as well as in theory, it will play an expected role to detect epithermal vein systems directly in the future mineral exploration.