Modeling Pit Lake Flooding After Mine Closure

S. Jordana[1], A. Nardi[1]
[1]Amphos 21, Barcelona, Spain

Most of mining works, either on the surface or in the underground, demand continuous groundwater pumping in order to operate under dry conditions. When the mining activity stops, dewatering also stops and mining facilities begin to flood, quite quickly at the beginning but becoming slower as the water level in the pit lake rises. The rise of the surface of the lake decelerates due to the bigger evaporation of water and the decrease of the groundwater pressure gradient towards the lake. Both effects are induced precisely by the surface lake rise. Therefore, incorporate this lake-flooding phenomenon into a hydrogeological model requires handling a nonlinear problem. The resulting model is able to recreate under transient conditions the pit lake generation.