Research on open-pit mine schedule planning method based on multi-objective optimization

In order to seek the optimal schedule under a specific open-pit mining program to maximize the economic benefits of the mine, the linear programming method was adopted. Aiming at the shortest time to reach production, the maximum total coal mining volume within 3 years after production and the minimum number of equipment transfers, the multi-objective of schedule planning was established with the constraints of equipment quantity, the relationship between the mining and stripping projects and the designed coal output. The model was optimized and solved using the priority method. The calculation method of the earliest investment and production year and the annual coal mining volume balance method were designed by using the on-table operation method and the reverse dynamic programming to design a schedule plan to reduce the number of transfers to prepare. Taking the mining of the Buzhaoba Open-pit Mine from west to east as an example, the number of electric shovels, annual production capacity, recovery rate, electric shovelling capacity, the number of trenching electric shovels and the number of expanding electric shovels were used as constraints. The plan has been compiled and the results show that：after reaching production, it can be mined to the 11th stage in the third year, and 87% of the ore rock in the 11th stage can be mined at the end of the year. The ore and rock scales in the 11th stage and the previous 10 stages were integrated, and used as the total mining and stripping engineering volume from the start of the infrastructure to the third year after production. the optimization model was iteratively solved to obtain the balanced mining and stripping amount, and the mining and stripping plan was completed by using the table-based operation method and reverse dynamic programming. The optimized schedule can be put into production in 3 years, and reach production in 5 years, the total amount of raw coal mining in the first 8 years will reach 37.19 Mt, and the number of equipment transfers will be 53 times. Compared with the average of the other three types of unoptimized schedules, the commissioning time is advanced by 0.3 years, the production year is advanced by 0.6 years, the total coal mining volume has increased by 3.7 Mt, and the total number of shovel adjustments has been reduced by 19 times. The above quantitative indicators show obvious advantages and verify the effect of this optimization method.