Therefore, geopolymers are gradually becoming the best alternative to Portland cement. [PERSON] [8] found that using fly ash or blast furnace slag can effectively reduce the alkali-silica reactivity of cementitious materials containing FNS fine aggregates. [PERSON] [9] et al. used steel slag to replace crushed stone and made cementitious materials with slag and coarse aggregates, which effectively improved the compressive strength and wear resistance of the cementitious materials and reduced their volume shrinkage. The raw materials of geopolymers are various industrial solid wastes and waste materials produced in a mining area [10], such as gangue, slag, red mud, and fly ash [11; 12; 13; 14; 15]. Geopolymers, because of their excellent mechanical properties and corrosion resistance, have become the development trend of future composite materials. [PERSON] et al. [16] improved the compressive strength and carbonation resistance of concrete by adding different ratios of lithium powder and slag to cement. [PERSON] et al. [17] enhanced the mechanical properties and durability of lightweight aggregate concrete by adding cementitious materials to lightweight aggregate concrete. Using the waste materials produced in a mining area to reconstruct a geopolymer aquifer can effectively reduce the cost and reduce the waste of resources [18]. Mudstone is tightly cemented due to its fine mineral grains and the cement is mud cemented [19; 20; 21; 22]; therefore, mudstone has low porosity [23; 24], strong confinement, low permeability [25], and is a natural water barrier [26]. Abandoned mudstone is a by-product of mining production, usually located at the top of the coal seam [27]. In the process of coal mining, abandoned mudstone is usually stripped and discarded at the dump site, and the reuse of abandoned mudstone can effectively reduce the amount of by-products of open-pit mining. With the progress of industry, the demand for iron in various industries has increased [28], and the production of slag, as a by-product of blast furnace ironmaking [29], has also increased. slag is usually treated as industrial waste in industrial production [30]. With the development of geopolymers in recent years, slag and mudstone, as typical high-silica-alumina materials, undergo locking reactions in alkaline environments and generate geopolymers [31; 32]. Geopolymers, because of their excellent mechanical properties and corrosion resistance, have become the development trend of future composite materials. Therefore, we studied a new type of waterproof material with mudstone and slag as cementitious materials and waste stone materials as aggregates. A MSWC has enough strength and low permeability to fulfil the requirements of reconstructing the waterproof layer of an open-pit mine dump. Due to the operation of equipment and the transportation of vehicles in the production of the mining area, in this study, according to the actual situation after the restoration of the dump, we conducted uniaxial compression tests, uniaxial cyclic loading and unloading tests, permeability tests, and SEM scanning tests on MSWCs with different mudstone proportions and analysed the change law of the permeability of MSWCs under the influence of different mudstone proportions and different uniaxial cyclic loading and unloading times. The relationship between the macroscopic fracture form and the microscopic structure of MSWCs was studied. Finally, by comprehensively analysing the permeability and uniaxial compressive strength of MSWCs, the optimal mix ratio of MSWC was obtained. This study broadens the development direction of mine solid waste as geopolymers, and has guiding significance for academic development and industrial production.