Underground hard coal mining usually disrupts the mechanical equilibrium of rock sequences, creating fractures within minor permeable rocks. The present study employs a dual-continuum model to assess how both fractured and porous sandstone media influence the percolation process in postmining setups. To test the approach, the software TOUGH2 was employed to simulate laminar fluid flow in the unsaturated zone of the Ibbenbüren Westfield mining area. Compared to other coal mining districts in Germany, this area is delineated by the topography and local geology, leading to a well-defined hydrogeological framework. Results reveal good agreement between the calculated and measured mine water discharge for the years 2008 and 2017. The constructed model was capable of reproducing the bimodal flow behavior of the adit by coupling a permeable fractured continuum with a low-conductivity rock matrix. While flow from the fractured continuum results in intense discharge events during winter months, the rock matrix determines a smooth discharge limb in summer. The study also evaluates the influence of individual and combined model parameters affecting the simulated curve. A detailed sensitivity analysis displayed the absolute and relative permeability function parameters of both continua among the most susceptible variables. However, a strong a priori knowledge of the value ranges for the matrix continuum helps to reduce the model ambiguity. This allowed for calibration of some of the fractured medium parameters for which sparse or variable data were available. However, the inclusion of the transport component and acquisition of more site-specific data is recommended to reduce their uncertainty.

地下硬煤开采通常会破坏岩石序列的机械平衡，在较小的可渗透岩石中产生裂缝。本研究采用双连续模型来评估裂缝和多孔砂岩介质如何影响采后设置中的渗流过程。为了测试该方法，使用了 TOUGH2 软件来模拟 Ibbenbüren Westfield 矿区非饱和区的层流流动。与德国其他煤矿区相比，该区域由地形和当地地质划定，形成了明确的水文地质框架。结果显示，2008 年和 2017 年计算的和测量的矿井排水量非常吻合。所构建的模型能够通过将可渗透的断裂连续体与低电导率岩石基质耦合来重现平硐的双峰流动行为。虽然来自断裂连续体的流动会在冬季导致强烈的放电事件，但岩石基质决定了夏季的平滑放电肢。该研究还评估了影响模拟曲线的单个和组合模型参数的影响。详细的敏感性分析显示了最敏感变量中两个连续体的绝对和相对渗透率函数参数。然而，对矩阵连续统的值范围的强大先验知识有助于减少模型的歧义。这允许校准一些可用的稀疏或可变数据的裂缝介质参数。然而，