What lies beneath – the use of thermal imagery and satellite data to observe tailings seepage and water risk and pre-empt failures (2023)

K.L. Morton and W.L. van Heerden
KLM Consulting Services Pty Ltd, South Africa

Abstract
The monitoring of movement of a tailings storage facility (TSF) is often too late to stop failure. Most failures are caused by the presence of water. Monitoring of the water level in the pond and the pore water in a TSF dam wall enables early warning of potential failures. Water pressure can be measured using vibrating wire piezometers and the occurrence of seepage zones can be detected using thermal imagery. Thermal imagery is a well-known technique for viewing ‘wet’ and ‘dry’ rocks. KLMCS used airborne thermal imagery in the 2000s to plot ground water occurrence for the Anglo American, Debswana and De Beers mines. Aerial surveys covered large areas and were used to observe seepage from the TSFs. Satellite data has also been used to plot TSF seepage on a smaller scale. Images from Maryland University are available for free and can be plotted as a first pass to assess if airborne surveys are worth the extra expenditure. Modern drones can carry thermal scanners and can be used at less expense than fixed wing platforms. Geophysical techniques can also be used to determine what lies beneath the face of a TSF. The paper shows examples from each method and provides images from each type of survey.

Morton, K.L. & van Heerden, W.L. 2023, ‘What lies beneath – the use of thermal imagery and satellite data to observe tailings seepage and water risk and pre-empt failures’, Next Generation Tailings – Opportunity or Risk?, Emperors Palace, Johannesburg, 24–25 October 2023, The Southern African Institute of Mining and Metallurgy.