The Structural Characteristic Research Of Covering Layer From Open Pit To Underground Mining

At present, many of our open pit mines are facing a common problem that, with the extension of open pit mining, stripping costs will continue to increase, the area of damaged land caused by exploitation is extending, the formation of the high and steep slope will bring serious threat to the mine, resulting in ever-increasing costs of mining. From the perspective of safety, economic development and environmental protection, these mines will have to change into underground mining from the current open pit mining.However, in the process of changing into underground mining, there are many problems to be solved. The security struture of the covering layer is one of the problems. The major role of the covering layer lies in the following aspects: to seprate the underground and the open ground, to slow down the infiltration rate of the storm water, to stagger the flood, and to avoid mudslides. The covering layer plays an important role in keeping the security of underground mining. The security structure of the covering layer has a direct impact on safety of the mine in production. Therefore, it is of great significance on theory as well as practical guidance to research on the structural characteristics of the covering layer.According to the movement of bult, a physical experiment model is established. The results of physical experiment on the movement of covering layer and simulation results are compared and analyzed by taking the means of computer simulation. Then the curve of the movement of loose particles of the covering layer and the permeability coefficient change curve and obtained and the reasons of the bulk of the coving layer, formed debris flow are analyzed. On the basis of the mentioned above, the leakage experiment model is established. The mines having formed the covering layer and also having changed into underground mining from open pit can use the model to estimate the time of leakage when the rainfall comes its peak in the area, thus to test the safety of the covering layer.The results of this research is very significant in preventing the formation of debris flow, providing valuable reference for the reasonable determination of the security struction of the covering layer. Also the results have practical significance in ensuring the safety in production of the mines changing into underground mining to some extent.