A case study on the use of infrared thermography to assess seepage zones in mining operations

Effective management of unsaturated fluid flow in open-pit excavations is critical, as mining disturbances like blasting can enhance fracture connectivity, permeability, and water infiltration, thereby compromising slope stability. This study evaluates infrared thermography as a non-invasive tool for detecting seepage zones in a fractured rock highwall at an open-pit quarry in South Africa. Field-scale measurements and photogrammetry data are used to gain a better understanding of unsaturated flow behaviour in fractured rock masses. Passive infrared thermography established baseline thermal anomalies associated with natural groundwater seepage, revealing distinct cooler surface patterns in highly fractured domains that aligned with geotechnical mapping. Active infrared thermography using controlled injection of cold water into the high wall enabled real-time thermal monitoring, confirming preferential channelling along lithological contacts. The findings demonstrate that infrared thermography is a powerful and reliable technique for remotely evaluating areas susceptible to seepage on high walls, highlighting its promise for improving hydrogeological risk assessment in mining operations.