Open-pit mining has increased substantially over the past two decades. Many currently operating open-pit mines are facing the end of mine-life over the next few decades and, increasingly, focus is shifting towards mine-closure planning that provides evidence on available closure options under the given geological, hydro(geo)logical and climatic conditions. This study uses synthetic groundwater modelling to build basic process understanding of closure options and how these will determine the formation of pit lakes. This governs the long-term pit lake water quality and how postmining landscapes may be utilised. Simulations show that the recovery time of postmining groundwater levels increases with decreasing aquifer transmissivity. Final postmining water tables are predominantly controlled by the implemented mine closure options and climatic conditions. The most important decision is, thereby, whether to backfill the pit to above the water table or allow a pit lake to develop. Under moderately transmissive aquifer settings, backfilling of pits leads to rapidly rising groundwater levels within the first decade after mining, with water-table recoveries of above 70%. If mine voids remain unfilled, evaporation from the pit lake surface becomes a governing factor in determining whether the unfilled mine pit becomes a terminal sink for groundwater. Lake levels may remain subdued by several 10s of metres in arid to semiarid climates. If surplus surface water can be diverted into open pits, rapid filling can accelerate groundwater recovery of open pits in regions of low permeability. This is a less successful management option in transmissive aquifers.

在过去的二十年里，露天采矿已大幅增加。许多目前运营的露天矿山在未来几十年都面临着矿山寿命的终结，并且越来越多的重点转向矿山关闭规划，该规划提供了在给定地质、水文（地质）和气候情况。本研究使用合成地下水模型来建立对关闭选项的基本过程理解，以及这些选项将如何确定坑湖的形成。这决定了矿坑湖的长期水质以及如何利用采矿后的景观。模拟表明，开采后地下水位的恢复时间随着含水层透水率的降低而增加。最终的采后地下水位主要由实施的矿山关闭方案和气候条件控制。因此，最重要的决定是是否将坑回填至地下水位以上或允许坑湖发展。在中等透水性含水层环境下，矿坑回填导致开采后的头十年内地下水位迅速上升，地下水位恢复率超过 70%。如果矿井空洞仍未填满，则矿坑湖面的蒸发量将成为决定未填矿坑是否成为地下水终端汇的控制因素。在干旱到半干旱的气候中，湖泊水位可能会保持低 10 米。如果多余的地表水可以转移到露天矿坑，快速充填可以加速低渗透地区露天矿井的地下水恢复。在渗透性含水层中，这是一个不太成功的管理选择。