Application of muon tomography in bauxite exploration

Abstract

Muon-based imaging, utilizing radiographic and tomographic techniques, is a powerful tool for detecting subsurface structures based on density contrasts. Unlike conventional geophysical methods, which are influenced by subsurface material properties, muography maps density along nearly straight muon paths, enabling high-resolution imaging even of small or deeply buried features. Detecting bauxite lenses beneath thick carbonate cover is particularly difficult using standard geophysics. In the Jajce–Poljane area of Bosnia and Herzegovina, we conducted muographic measurements from an underground adit beneath a known bauxite lens, using borehole data to guide detector placement. The bauxite–limestone density contrast may be as low as 0.3–0.4 g/cm3. The lens is overlain by ∼50 m of limestone, beneath irregular karstic topography. Simulations conducted in this study indicated that the lens should be detectable despite its modest density contrast. The muon tomographic survey from the adit at 1036 m elevation probably successfully imaged the lens, delineating its lowermost and uppermost extents at approximately 1062 and 1072 m, respectively, confirming the simulation predictions.