Satellite bathymetry for the monitoring of supernatant water volumes within tailings storage facilities

The availability of water plays a fundamental role in the operational continuity associated with mineral and metal extraction operations. As part of this process, it is necessary to recover as much water as possible for reuse and reduce make-up water requirements while trying to maintain a reduced impact on the surrounding environment and natural resources. Specifically related to tailings disposal, the past few decades have seen a shift towards high-density tailings with advances in thickening and filtering technologies, thus improving the water recovery and reducing the volumes of water deposited within a tailings storage facility. However, the vast majority of tailings facilities worldwide still generate a supernatant pond as the tailings naturally consolidate and bleed. These ponds need to be controlled in their size and volume, particularly in larger throughput operations. In some countries, it is a requirement to report volume to the authorities on a routine basis. This paper presents a study to monitor the growth of supernatant ponds in tailings facilities using remote sensing techniques. Principally, this relates to a multispectral analysis of satellite bands which, by means of various corrections and applications of combinations of these bands through mathematical algorithms, the depths of relatively shallow supernatant ponds can be determined reasonably accurately. The importance of the study is to provide an alternative to current in situ monitoring techniques, such as sonar instrumentation, which is limited to a minimum depth. The added advantage is that satellite monitoring delivers information quickly and cost effectively and, more importantly, avoids the requirement for human presence, thus reducing operational risks.