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Metal Mine ›› 2020, Vol. 49 ›› Issue (09): 48-53.

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Effects of Early Strength Accelerators on the Strength of Filling Body Comprised of Consolidated Powder and Mixed Aggregate

YANG Xiaobing,GAO Qian,WANG Yongding,HE Jianyuan   

  1. 1. School of Civil and Resource Engineering,University of Science and Technology Beijing,Beijing 100083,China;2. Longshou Mine,Jinchuan Group Co.,Ltd.,Jinchang 737100,China
  • Online:2020-09-15 Published:2020-10-16

Abstract: For the utilization of waste rock and consolidated powder in Jinchuan mining area,firstly,the particle size grading analysis of mixed aggregate was carried out with different ratio of waste rock to rod mill sand.The results show that the packing density and Talbol power index n of the mixed aggregate with ratio of 4∶6 were 0.635 and 0.591 respectively.Then,as the ratio of waste rock in mixed aggregate increasing from 10% to 50%,unconfined compressive strength tests were taken for the filling body with and without early strength accelerators respectively.The study results show that the strength of fill body increases firstly and then decreases as the increasing of waste rock content.When the ratio of waste rock is 40% and the slurry mass concentration is 79%~81%,the average strength of fill body without early strength accelerators in three curing periods (3 d,7 d and 28 d) was 1.23 MPa,3.79 MPa and 5.98 MPa respectively,and its early strength is lower than the mine designed strength.By adding early strength accelerators,the average strength of filling body in three curing periods reached 1.55 MPa,3.34 MPa and 6.46 MPa respectively,meeting the needs of cemented backfill strength by the downward slicing drift mining operation in Jinchuan mining area.Therefore,with cement- aggregate ratio of 1∶5,waste rock-rod mill sand ratio of 4∶6,slurry mass concentration of 79%~81%,the mixture comprised with consolidation powder,mixed aggregate and 1% early strength accelerators could be widely applied in Jinchuan mining area.

Key words: filling mining, early strength accelerators, consolidation powder, mixed aggregate, packing density, strength of filling body