Geophysical Monitoring of Mining-related Deposits in the MOSMIN Project

Residues of industrial mining activities like rock waste, tailings, and stockpiles are amongst the largest human-made structures in both area and volume. In the case of tailings dams, the risk posed by failure is well documented and has led to the implementation of regulatory standards. As one of the measures to reduce potential harm to the environment and people, the Global Industry Standard on Tailings Managment (GISTM) implemented by UNEP in 2020 proposes the installation of "monitoring systems to manage risk at all phases of the facility lifecycle". This is one of the objectives of the EU-funded project MOSMIN (Multiscale observation services for mining-related deposits), which strives to develop holistic, full-site services for the geotechnical and environmental monitoring of mining-related deposits through the combination of Earth observation with in situ geophysical data. The integrated data sets should then be leveraged by using modern analysis approaches like machine-learning to characterize deformations and identify environmental hazards.

 

In this work, we present the in situ geophysical campaigns conducted to acquire passive seismic data at two tailings dam facilities both related to copper mining, namely the tailings storage facilities of the FQM Trident mine in Kalumbila, Zambia, and the Codelco Chuquicamata mine near Calama, Chile. Both installations combine conventional seismic sensors with the deployment of a fibre-optic sensing array over targeted tailing dam sectors, for the continuous recording of ambient seismic noise. The main goal of this approach will be to both characterise the internal structure of the dams underneath the fibre-optic array and to monitor subsurface processes at different scales, resolutions and depths of investigation. We aim to apply several seismological methods for structural and material property characterization, the investigation of temporal changes in seismic properties and the evaluation of material contrasts in the body of the tailings dam. Suitable methods are ambient noise tomography and horizontal over vertical spectral ratios (H/V). Details of both setups like instrument deployment, fiber cable and trajectory, the procedure and construction of the layout, as well as preliminary results will be discussed.