Assessing the effect of snowmelt on mine covers in cold climates using numerical modelling and laboratory columns

Authors: Saafan, A; Toromanovic, J; Maurice, C Download Paper Open access courtesy of:

DOI https://doi.org/10.36487/ACG_repo/2515_92

Cite As:
Saafan, A, Toromanovic, J & Maurice, C 2025, 'Assessing the effect of snowmelt on mine covers in cold climates using numerical modelling and laboratory columns', in S Knutsson, AB Fourie & M Tibbett (eds), Mine Closure 2025: Proceedings of the 18th International Conference on Mine Closure, Australian Centre for Geomechanics, Perth, pp. 1-12, https://doi.org/10.36487/ACG_repo/2515_92



Abstract:
Multilayer cover systems are commonly used for reclamation of waste rock and tailings facilities to prevent the diffusion of oxygen to underlying mine waste. The construction of this type of cover needs large amounts of soil material. The material needs specific hydraulic properties, e.g. the sealing layer properties that are difficult to reach, such as low hydraulic conductivity and high water-retention capacity. To enable the use of locally available soils that do not meet those requirements, a proposed solution is to include a bentonite mat in the sealing layer. In this study, the performance of a sealing layer composed of a bentonite mat associated with a layer of either compacted or uncompacted till is evaluated. The cover is evaluated using numerical modelling and laboratory columns built as a replicate of a field trial. The cold climatic conditions of boreal areas are characterised by a dry winter period accumulating precipitations that are released during a short and wet snowmelt period. The objective of the research is to simulate and understand the effect of such rapid succession of water regimes, including the effect of snow cover, on the water balance in the cover and its effect on the performance of the cover. Field trial monitoring data obtained from soil moisture sensors were used to calibrate and validate the numerical model, ensuring its accuracy and reliability in predicting the performance of multilayer cover systems under real weather conditions. This approach allows a better understanding of how a multilayer cover will perform during the dry winter, the wet snowmelt, and the humid summer and autumn. Combining laboratory columns and numerical modelling is hypothesised to provide an efficient way to assess the performance of different designs.

Keywords: mine cover system, numerical model, field pilot test, laboratory column test

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