Use of integrated geophysical technology for exploring gem gravel beds in Rathnapura district, Sri Lanka

Abstract

The pursuit of gemstones has captivated humanity for centuries, driven by their beauty and value. In Sri Lanka gem mining is carried out in a haphazard manner (blind digging) using conservative methods and without having an idea about the subsurface geology. The gem deposits in Sri Lanka are mainly secondary deposits which often occur in riverbeds, alluvial plains, and sedimentary environments. In this research, the aim is to enhance the exploration of gem gravel beds by leveraging integrated geophysical technology. Focusing on Sri Lanka's rich gemstone heritage, particularly in renowned areas like Rathnapura, this study utilized Ground Penetrating Radar (GPR) and resistivity surveying techniques to pinpoint gem-rich gravel layers with greater accuracy. By combining these advanced methods, the research aims to develop efficient and non-destructive approaches to delineate gem-bearing gravel beds, thereby minimizing environmental impact and maximizing resource recovery. Using the GPR instrument and GPRSoft software, could successfully interpret a profile which gives proportional results with the actual cross section of the gem pit and could utilize resistivity instruments to interpret a profile in low depth area of the mine site as well. Furthermore, through this research, empowerment of gem miners with precise data, contribution to the sustainability of Sri Lanka's gem industry, and advancement of scientific knowledge in geophysical exploration techniques are fulfilled.