Mining method optimisation of Bayi gold mine based on the value engineering principle

Abstract

Bayi gold mine is located in the northeast of Habahe County, Altai city, Xinjiang autonomy region, China. There are No. 1 and No. 2 mining districts in the mine, of which No. 1 is the main production district. The group of 12# veins is the main orebody, of which the top veins over +610 m were mined out with the open pit mining method. The upper part of the remaining orebodies is mined underground with the short-hole shrinkage stoping method. However, at about +400 m level, those veins gradually merge into one 30-60-m thick orebody, hence the mining method for the lower thick orebody has to be changed. For safe mining, the backfill method has been suggested. In this paper, mining method selection was regarded as a system engineering problem with multi-objective decision-making. In the primary selection, three kinds of underground backfill mining methods were proposed. A comprehensive multi-objective decision-making index system for mining method optimisation was built up based on the value engineering principle, and technical feasibility, resources utilisation and economic benefit factors were taken in consideration for safe mining and environmental protection. In order to integrate the experts' experience and to put the original qualitative comparison into quantitative analysis, the comparative importance of the functional parameters decided by the 0-1 compulsory scoring method was introduced. Therefore, the functions and values of primary selected mining methods with unified multi-objective data for comparison were obtained. Based on that, the optimised mining method, i.e. sublevel open stoping with delayed backfill, was selected. The final optimised mining method was designed and put into stope preparation.