| Staged mining can give priority to mining in the area with high coal grade and less stripping amount,effectively reduce the amount of rock stripping in the initial stage of mining,delay the peak of rock stripping and recover funds as soon as possible,so as to reduce the risk of investment and operation investment and improve the economic benefits of the mine.The number of stages,stage boundary and final boundary are the three key elements of stage scheme design,which have an important impact on the economic benefits of mining enterprises.At present,the optimization of the staging scheme at home and abroad is to determine the final state first,and then divide it into the staging state,but determining the final state first will limit the optimization space of the staging scheme,and it is difficult to get the global optimal solution.Based on the existing research results,this paper regards the number of stages,the stage boundary and the final boundary as a "whole".In the optimization process,it does not take any of the factors as the known conditions,but as the state of space-time development.It considers not only the interaction between the stages,but also the influence of the spatial development path of the stage boundary and the final boundary,Then,the multielement optimization of the staging scheme can be realized at the same time.This paper introduces the principle of staged scheme and the definition of geological optimal boundary,the method of generating candidate boundary sequence and the principle of dynamic programming,expounds the basic idea of staged boundary optimization,sums up the above methods and principles into algorithms,and establishes the optimization model.In view of the nearly horizontal distribution characteristics of open-pit coal deposits,the fault treatment,coal seam boundary control and aggregation effect are fully considered in the modeling process,so as to make the coal seam columnar model more practical.At the same time,the column model instead of the traditional three-dimensional block model can avoid the phenomenon of coal rock mixing at the junction of coal and rock,improve the accuracy of coal rock mass calculation,and make the optimization results more accurate.In this paper,the actual mine as an example,first of all,assume that in the future period of time,the coal mine market fluctuation is small,carry out the whole boundary optimization,get the whole boundary optimization scheme.Then,given a very high price,the cone exclusion method is used to delineate the maximum boundary,determine the increment of adjacent ore quantity,and generate a series of optimal candidate boundary sequences.The dynamic programming method is used to obtain the benchmark phased optimization scheme.Comparing the whole boundary optimization scheme with the benchmark optimal staged optimization scheme,it can be found that staged mining can effectively reduce the amount of rock stripping,delay the peak of rock stripping and improve the net economic value.Two kinds of price models,weighted moving average and grey prediction,are established to predict the coal mine market.According to the parameter prediction results,the optimization results of staging scheme are analyzed when the market fluctuates.The results show that:when the price growth rate increases from 0.9%to 1.7%,the volume of raw coal mining fluctuates greatly,and the final state has high sensitivity to the price,which can avoid the market risk;When the price growth rate increases from 1.7%to 1.9%,the increment of raw coal mining does not change,and the sensitivity of the final state to the price is low,which indicates that the final state under this growth rate is close to the maximum state. |
