(1. Key Laboratory of High Efficient Mining and Safety of Metal Mine，Ministry of Education，University of Science and Technology Beijing，Beijing 100083，China；2. Department of Civil Engineering，University of Ottawa，Ottawa K1N6N5，Canada；3. Fujian Sangang Group Co.，Ltd.，Sanming，Fujian 737100，China)
Abstract：In order to achieve the goal of safe，efficient and low-cost mining，it is necessary to determine the reasonable strength of the backfill. Firstly，the test materials are analyzed to determine the ratio of mortar strength test. Secondly，according to the test results of different proportion of mortar，the relationship between the strength of backfill and the curing age is analyzed，and the relationship expression between them is established. Then，the matching coefficient K is introduced to characterize the matching relationship between cemented backfill and ore rock energy，and the reasonable strength of backfill is determined accordingly. Finally，according to the example of Makeng Iron Mine，the matching characteristics are analyzed，and the reasonable strength of backfill with different rock properties is determined respectively. And then the matching analysis between the solidification time of cemented backfill in one-step goaf and reasonable mining time of two-step pillar mining is carried out. On this basis，the ratio of filling slurry and the mining time of two-step are determined，and is verified by industrial filling. The results show that under the same condition of cement-sand ratio and slurry concentration，the strength of backfill increases exponentially with the curing age；the matching coefficient K of cemented backfill and ore rock energy is closely related to the deformation modulus and bulk density of ore rock，mining depth and strength of backfill；According to the energy matching characteristics of cemented backfill and ore rock，combined with the actual situation of the mine，when the ore rock is moderately stable，the filling ratio of one-step goaf is cement sand ratio of 1∶4 and concentration is 75%. When the ore rock is partially broken，the filling ratio of one-step goaf is cement sand ratio of 1∶4 and concentration is 78%，after solidification for 12 d and 17 d respectively，two-step stoping is carried out. After verification of industrial filling，the strength distribution of the sample ranges from 2.35 MPa to 3.28 MPa，which meet the requirements of mine strength.
2021, Vol. 40 
