Study On Dynamical Optimization And Application Of Open Pit Mine Limit

The mining industry provides an important material base for social and economic development. Open pit mine has the biggest share in the solid ore deposits. The final limit delineation of the open pit mine is the basis of mining design and the premise of mine development in economy, safty and efficiency. The mining experts from different countries have done lots of research and study on the open pit mine limit optimization for a long time, and obtained many achievements. However, due to the changing nonlinear dynamic factors in open pit mining, e.g. complex geological rock, the disorder grade distribution and fickle economic parameters, it's particularly difficult to obtain the optimal limit. Aiming at the problems in limit optimization, the treatise proposes the topic of dynamic optimization of mine limit, and study the definition method of economy and safety final limit of open pit, on the basis of large survey data and actual cases, and also using mathematical statistics, artificial intelligence, numerical simulation, graph theory, three-dimensional simulation and dynamic assessment of economic benefit.The main contents are:on the basis of previous work, the dynamic characteristics of limit is studied; by taking the historical data of metal prices as a platform, the prediction method of the economic parameters by statistical theory is studied; pit slope angle is forecasted by artificial intelligence method; the creation method of series pit limits are researched; by means of3D simulation, dynamic excavation of complex open mine under multi-level constraints is realized, excavation quantity and grade of ore are obtained as well. Using the economic effect dynamic evaluation theory, the method of mining limit dynamic optimization is obtained.Main achievements are as following:(1) The time impact on open pit mine limit is revealed. The dynamic evaluation index system of open pit limit dynamic optimization and the calculation method of mine net present value is formed. The research enriches and perfects the basic theory system of last limit dynamic optimization, and establishes the solid theoretical basis for further study and application.(2) With the copper price over years collected, the forecast model of copper price in time series is created, which is used to predict metal prices. It's the first time to apply the time series theory to gain the metal price parameter in the process of mine limit optimization.(3) Prediction model of open pit mine slope angle is built, with the BP network model improved. Numerical model of slope angle is created by the method of data coupling (Surpac, Madis and Flac3D), to verify the predicted results from BP network model.(4) The deposit model creation practical technology which is required to form series limits is analyzed and summarized. Primary election method of basic economic parameters which is required to generate series limits is proposed. The requirements on the error of each parameter of series limits are analyzed, a specific solution on the state gap and a series states generating method based on analysis of weighted parameter is formed, and series limits are achieved.(5) Using computer three-dimensional simulation technology and three-dimensional simulation scheduling software Minesched, the efficient visualization preparation of open pit production schedule is achieved.(6) For the engineering practice of a large copper mine, using multiple means combination method and integration optimization method, the stripping order and the final limit of the copper mine are dynamically optimized. The results show that, multiple means combination method holds the advantages of high accuracy, operability, etc. and is more suitable in detailed design optimization and production planning stages of mine; integration optimization method is efficient, fast, but the optimization results are slightly rough, so it is more suitable in mining pre-program planning stage.The research systematically and deeply studies the open pit mine limit dynamic optimization method, using multi-disciplinary theories and methods, and is of high value in theory and application. It can be the theoretical and technical basis for overall optimization of open mining.