Division of Sustainable Resources Engineering, Faculty of Engineering, Hokkaido University, Kita 13 Nishi 8, Sapporo 060-8628, Japan; Mitsubishi Materials Corporation, 3-2-3, Marunouchi, Chiyoda-ku, Tokyo 100-8117, Japan.
Division of Sustainable Resources Engineering, Faculty of Engineering, Hokkaido University, Kita 13 Nishi 8, Sapporo 060-8628, Japan.
J Contam Hydrol. 2020 Mar;230:103617. doi: 10.1016/j.jconhyd.2020.103617. Epub 2020 Jan 25.
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%.
本研究评估了一个假设，即填充旧采空区的区域可以被模拟为多孔介质，地下水流动受达西定律控制。日本山形县的八幡矿山被选为研究对象，因为在其开采过程中使用了多种采矿方法，并且可以获得该矿山采空区的详细图纸。该模型使用水力传导率（k）的组合进行了校准，通过比较计算出的和测量得到的 AMD 通量，选择了最佳匹配的案例。当考虑到采空区是具有特定水力传导率的多孔介质，并且考虑到断层和渗透率的存在时，沿排水隧道（-2 L 水平）的模拟 AMD 通量与测量数据一致。该模型还成功预测了从竖井到入口的 AMD 通量增加的趋势。在数值模型中，假定填充的采空区表现为多孔介质，这在该矿山中被证明是一个有效的假设。该模型表明，用低渗透性材料回填采空区和排水隧道可以将 AMD 中 Zn 的通量减少多达 61%。
