Abstract: It is difficult to control the ore loss and dilution by caving mining methods in the actual operation，and the formation and rupture of mullock funnel is the main cause of ore loss and dilution in the process of ore drawing.In order to delay the formation of mullock funnel and the time of overlying rock arriving at the ore drawing point in the process of ore drawing，a non-pillar stage caving mining method with overhangs structure is carried out.Using this method，each lower sublevel is pulled ahead of its upper sublevel by an overhangs distance，and an overhangs structure is formed on the working face of mining roadway.The mining work is conducted under the cover of the overhang structure that is right above it.In order to verify the ore drawing effects of overhangs structure，the multi-sublevel ore-drawing model is used to carry out two groups of similarity simulation experiments regarding the overhang structure and traditional ore-drawing. The experimental results show that the ore dilution rate of the overhangs structure can be reduced by 5.3 % when the ore recovery rate is maintained at 80%. In Gongchangling underground mine，the overhangs structure of 4-5 perforating veins in -280~+48 m section is tested.The overhangs structure and the original structure are measured by drawing shift with nine caving steps.The study results show that compared with the original structure，ore dilution rate of the overhangs structure can be reduced by 3.8%，the main reason can be described as that the overhangs structure can break the overburden rock falling down directly，and oblige them moving to the behind of the caved orebody in this sublevel，thus，the amount of pure ore drawing out is increased，and the dilution is reduced.The above study results further indicated that the overhangs structure scheme is simple to construct，and it is suitable for underground mining of orebodies above medium-stable level.

Key words: Underground mining, Non-pillar stage caving mining method, Overhangs structure, Ore loss and dilution, Mullock funnel, Similar simulation experiment