| Scraper is widely used in pillarless sublevel caving due to its high ore drawing efficiency, mobility, flexibility and general purpose application. In scraper sizing, the mining structural parameter, one ore-caving amount, production capacity and economic benefit are considered by the mines. However, since long ago there hasn't been a quantizing calculation method for the selection of the shovel size of scraper and the analogy method has been used and the real cases of both internal and external mines have been taken as example, resulting in unsatisfactory results. Therefore, it would be of great significance to explore the relationship between scraper sizing and the related factors. It can provide scientific basis for the decision-maker in scraper sizing for mines.It is considered that the aim of multiobjective decision-making can be attained by setting schemes in a sequence of superiority which is made according to weighted average deflection of desired solution of various decision-making objectives and by fuzzy mathematical theory. In view of the real fact that sublevel caving is mainly used in China's mines,, simulation mining is made on five shemes with the shovel size of scraper being 2m3, 3m3,4m3,5m3 and 6m3 respectively, Four indexes (objectives) are obtained througth the simulation for each scheme, namely, engineering investment, equipment investment, unit-shift efficiency of ore drawing and operation cost. Then, multiobjective fuzzy decision-making is used to establish in a stepwise way the multiobjective decision-making model(matrix), initial decision-making matrix, weighted fuzzy set matrix and fuzzy decision-making matrix. In the optimal principle, the desired solution is sought, based on which decision is made. Study is made on extracting equipment sizing for mines using subleyel mining by this method. It is concluded that with a hauling distance of 50-70m and a space between drifts of 10m, a 3m3 shovel size should be selected for the scraper; for a drift space of 15m, 4m3 shovel size; and with 20m drift space, 5m3 shovel size. With a hauling distance of 100m and a drift space of 10m, 3m2 shovel scraper should be selected; and with a drift space of 15-20m, 5m3 scraper.Based on the above, it is pointed out that with a hauling distance of 100m, sublevel height of 20m and a drift space of 20m, the ore drawing efficiency will be greatly raised if 6m3 -scraper is used. With otherparameters unchanged, the similar optimization obtained a sequence of superiority of scraper shovel size as: 6m3, 5m3, 4m3, 3m3 and 2m3, which just represents the present development trend of large scaling of both mining structural parameters and ore-drawing equipment.
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