Flexible magnetic suction impermeable membrane of vertical curtain water interception technology for strong seepage loose layer of coal mines

With abundant mineral resources, many types of mining industry and many mines, mining development in China has led to the decline of groundwater level around the mines, waste of water resources, water quality pollution, surface collapse, land degradation, reduction of vegetation cover, and different degrees of impact on groundwater resources and ecological environment. In order to solve the problems of water waste and ecological damage caused by the lateral recharge of water from the strong seepage loose layer to the mine pit, we proposed a vertical curtain water interception technology with flexible magnetic suction membrane to protect the groundwater resources and ecological environment of coal mines. We firstly studied the performance of the suction membrane material, developed the magnetic absorption suction membrane connection process, and carried out indoor tests of different suction membrane connection processes, then we conducted a 1 369 m strong seepage loose layer water interception curtain field test application in the test mine. The research results show that the impermeable membrane has low permeability coefficient, dense structure, high flexibility, resistance to deformation and durability, and is a good material for water cut, pollution control and seepage control, which can meet the requirements of vertical curtain for the strong seepage loose layer of the mine. The self-developed magnetic suction joint material and connection process solved the problems of shallow laying depth, joint leakage and complicated operation of existing connection processes such as overlapping lap, joint lock and joint box, etc. The construction depth of suction membrane curtain connected by magnetic suction joint is not limited by the connection conditions, and the water interception effect of magnetic suction joint connection process is better than that of overlapping lap and joint lock (joint box) connection process. Through the test of making, laying, connecting and backfilling the curtain into a wall with 2 kinds of flexible magnetic absorbent impermeable membranes, the gap at the joint of the impermeable membrane was reduced from 5-20 cm to 0, and the two adjacent impermeable membranes were closely connected as an organic whole, which reduced the water passage of the interception curtain at the joint. Through the mine-field site test, it was found that the water catchment pits below the curtain which had been filled with strong seepage loose layer water leakage for a long time, had dried up, and the water level of strong seepage loose layer outside the curtain had increased by 5.55-9.12 m, and the water level inside the curtain had decreased by 3.21-5.84 m, so the protection of strong seepage loose layer water resources had achieved good results.