Large Mined-out Area All Backfilling Filling Treatment Engineering Research And Practice

The research in this paper aims at the solution on two major problems of safety in Dongguashan copper mine. One is that the large group of mined-out areas threatens the sustaining production of the deep mining beneath in the mine and influence on the environment; the other is the stockpiling problem of the unclassified tailings relating to the deep deposits mining. Referring to the current treatment methods of mined area and the conditions of the mine, the unclassified tailings filling is chosen to solve these problems. For the technological problems in the total tailings filling of the group of large mined-out areas, the filling material, slurry preparation, pipeline transportation, drainage and stability of rock mass around filling areas were studied. The major contents and results of this study are as follows:1. The tailings deposit tests were conducted to establish the physical model of filling tailings. The comparison tests of different filling concentration and different filling height revealed the flow properties deposition process, filling effect, filling pressure and piping condition of tailings, which provide the basis for management of large mine-out area filling.2. For the preparation of very fine particle tailings, the decompression in gravitational transportation of high concentration unclassified tailings slurry, and separation of water from talls and drainage in fine particle taillings, it was creatively put forward that the "high location filling、multi-level drain and intermittent filling" filling process, and consequently, the more advanced techniques of the mined-out treatment wrer achieved, combined with the block wall structures and monitoring measures.3. The stability of rock and filling effect were analysed with the finite difference method. The calculation shows that total tailings filling will significantly improve the stress state of the wall rock. The site ground pressure monitoring indicates that total tailings filling will well control the pressure activities. The survey for verification of the results demonstrates that the fillings has good density, good particle and good stability.