针对锦丰金矿粗骨料原材料自身强度低、矿岩遇水易泥化、尾砂粒级组成细及充填倍线大的现场条件,采用正交设计方法开展针对不同充填料浆质量分数、水泥掺量及人工砂与尾砂质量比优化研究;对充填料浆流动性指标和充填体强度指标规律进行分析。研究结果表明:当充填倍线为3.7~6.9,料浆质量分数为75%,人工砂与尾砂质量比为2.9,水泥掺量为12%~20%时可以实现自流充填要求;扩散度相对于坍落度对衡量自流充填料浆流动性具有更好的适应性;低强度充填骨料对充填体强度影响显著;当采矿进路最高达8.5 m时,充填体强度达到0.5 MPa即可保持良好自立性,并能有效支撑顶板;当充填体强度达到1.2 MPa时即可满足大型无轨设备行走需求,该值明显低于同类矿山技术要求。
Based on the fact that at Jinfeng Gold Mine,the strength of the raw coarse material(aggregate) is very weak,disintegrates when it is mixed with water,and full tailings granule is very fine and with a constraint of high stowing gradient(ratio of whole backfill pipe length to vertical height of the pipe),backfill optimization study was warranted.Using orthogonal experimental design methods,backfill mix was optimized in terms of slurry density,cement dosage,mass ratio of aggregates and tailings.Slurry fluidity indices and backfill strength indices were investigated.The results show that when the mass fraction of slurry is 75%,mass ratio of aggregates to tailings is 2.9 and cement dosage is 12%-20%,the requirements of gravity transportation of slurry can be fulfilled with 3.7-6.9 backfill stowing gradient.Diffusivity is more applicable than that of slump test when fluidity of gravity backfill slurry is considered.Aggregate made of low strength rock has a great influence on backfill strength.The strength(UCS) requirement for 8.5 m vertical exposure of the backfill is about 0.5 MPa,which can also efficiently support the roof of the stope when mining the next stope.Strength of 1.2 MPa will be adequate for mobile equipment working on top of the backfill.The strength requirements for vertical exposure and for equipment working on top of the backfill are significantly lower than strength requirements of other similar mines in China.