Void discovery inside Esztramos Hill using muographic methods

Muography is a novel geophysical method that allows the determination of density distribution inside large objects by measuring the flux of cosmic muons that travel through them. By comparing the measured data with atmospheric muon flux models and conducting 3-D muographic inversion on multiple datasets it is possible to accurately locate density anomalies that might indicate cavities. The Esztramos Hill, located in northeastern Hungary, was subject to decades of iron ore and limestone mining, which led to the discovery of multiple caves ranging from a few to a few hundred meters in length. A muographic detector system was installed in four positions inside one of the abandoned drifts to explore the surrounding area over several months. The evaluated data confirm the location of partially collapsed, inaccessible mined-out stopes and indicate the existence of a possible cave nearby.