Application of Infrared Thermography and the Acoustic Emission Technology for Loose Rock Detection

Abstract In underground mining and tunneling, the scaling process represents a critical safety procedure to create secure working environments by removing loose rock. In this context, the detection of loose rock is of great importance. Only if it is identified correctly, it can be fully removed. Since there are no standardized criteria for loose rock identification it is necessary to rely on subjective operator experience. The general development towards higher automation and an increasing shortage of skilled labor promote the use of sensor technologies for loose rock detection. This paper presents a novel approach for loose rock detection combining infrared thermography (IRT) and the acoustic emission technology (AET) including validation of the feasibility in a fluorspar and barite mine in Germany. The results of applying IRT are consistent with previous studies offering a further opportunity of disturbing the thermal equilibrium through the scaling process itself. Applying AET for loose rock detection allows an indirect detection of loose rock. The investigations demonstrate that both technologies can generally be applied for loose rock detection during mechanical scaling. However, the results also show that certain factors, such as environmental or rock specific parameters, affect detection and need to be further investigated in future work.