Complex UAS-Geophysical Surveys at the First Stages of Geological Prospecting: Case in the Western Sayan (Russia)

Abstract

Summary One of the most real factors of geological exploration optimization is low-altitude Earth remote sensing that includes geophysical prospecting methods. This article describes a case of the efficient application of complex low-altitude UAV-based aerogeophysical surveying during greenfield prospecting for gold in greenfield localized in the Western Sayan mountains (Russia). 90 sq. km site characterized by extremely complicated landscape and terrain conditions as well as controversial views on its geological conditions. Surveys from a multirotor UAV (unmanned aircraft vehicle) were made with terrain flowing and included a simultaneous magnetic and gamma-ray radiometric surveying as well as gamma-ray spectrometry by the ‘static hovering’ method and multispectral photogrammetry. The articles sets forth main principles of the method applied as well as demonstrates the advantages of unmanned aircraft technologies vs. traditional geophysical prospecting methods, i.e. high performance and low costs even in those conditions when ground and aerial surveys are economically impractical or entirely impossible. Application of low-altitude UAV-surveys allowed for a large-scale geological and geophysical mapping involving low costs, for clearing up a controversial point of the site geological conditions and for planning further prospecting, while avoiding erroneous solutions prompted by wrong priori assumptions about a geological structure of the site.