This study evaluated the assumption that back-filled excavated areas of old mine workings can be modeled as porous media, where groundwater flow is governed by Darcy's law. The Yatani mine, located in Yamagata Prefecture, Japan, was selected for this study because several mining methods were used during its operation and detailed drawings of the excavated areas of the mine are available. The model was calibrated using combinations of hydraulic conductivities (k), with the best-matched case being selected by comparing calculated and measured AMD fluxes. Modeled AMD fluxes along the drainage tunnel (−2 L level) were consistent with measured data when the excavated areas were considered to be porous media with a specific hydraulic conductivity, and the presence of faults and permeability were taken into account. The model also successfully predicted the increasing trend of AMD flux from the shaft to adit mouth. In the numerical model, the back-filled excavated areas were assumed to behave as porous media, which was shown to be a valid assumption in this mine. The model demonstrated that back-filling the excavated areas and drainage tunnel with low permeability materials could reduce the flux of Zn in AMD by up to 61%.

这项研究评估了这样一个假设，即可以将旧矿山的回填开挖区域建模为多孔介质，其中地下水流量受达西定律控制。选择位于日本山形县的八谷谷煤矿进行这项研究是因为在其运营过程中使用了多种采矿方法，并且可以获得该矿山开挖区域的详细图纸。使用水力传导率（k），然后通过比较计算出的和测得的AMD通量来选择最匹配的情况。当开挖区域被认为是具有特定水力传导率的多孔介质时，沿排水隧道的模拟AMD通量（-2 L水平）与实测数据一致，并考虑了断层和渗透率的存在。该模型还成功预测了AMD从轴到入口腔的通量增加趋势。在数值模型中，假定回填开挖区域表现为多孔介质，这被证明是该矿山的有​​效假设。该模型表明，用低渗透性材料回填开挖区和排水隧道可以使AMD中的Zn流量降低多达61％。