The effect of the metal deposits exploitation on the safe operation of water conservancy project

Ground subsidence which is caused by metal mining is generally forecast using research results and experiences of coal mining for reference at present. This paper considers that predictive study on the ground subsidence, which is induced by metal mining, must use suitable calculation methods under some specific circumstances. A comprehensive research method combining numerical simulation and engineering analogy is the most reasonable approach to predict ground subsidence induced by mining. The author takes practical engineering as example, firstly, a three-dimensional geological model was established on the basis of surveying and mapping for the study area in large scale using the three-dimensional laser scanner. Secondly, the rock fragment strength was tested with the Schmidt hammer and the rock point load strength instrument; at the same time, a detailed statistical analysis of joints and fractures of underground rock were made, and strength indexes of surrounding rock were determined on the basis of rock mass classification according to the rock mass rating (RMR) classification system. Finally, the surface movement induced by mining and the seepage field of the Boziliang Sub-dam were simulated using fast lagrangian analysis of continua in three dimensions (FLAC-3D) and Visual Modflow, respectively. The results of simulation indicate that it would not affect the safe operation of the Boziliang Sub-dam as long as the exploitation in the Madaozi iron mine conformed with the design requirements and was accompanied by monitoring work and the worked-out areas being filled in time.