充填体覆盖层块度分布对无底柱分段崩落法矿石回收的影响

Study on the influence of the block size distribution of the cover of fill mass on the ore recovery in sublevel caving without sill pillar

某矿山在下向分层胶结充填法转无底柱分段崩落法的过程中,冒落的胶结充填体形成了崩落法开采所需的散体覆盖层,由于充填体强度较低,在后续开采过程中受移动、挤压、摩擦等因素影响,其块度会变小,该现象对矿石回收效果的影响有待研究。根据实际采场分段高度、进路间距等参数按1∶100的相似比设计试验模型,以白云岩为矿石、铁矿石为充填物料,针对两种级配的充填体覆盖层共设计3组试验,其中试验1、3、5采用的充填物料级配与初始冒落块度分布相同,试验2、4、6采用的充填物料级配与二次破碎后块度分布相同,试验采用的矿石级配均与现场矿石块度分布相同,分别在1595、1580、1565、1546 m分段开展了放矿试验,结果表明:采用无贫化放矿时,充填体块度变小后矿石回收率、贫化率基本不变;采用低贫化放矿,当增大出矿量使贫化率升至7.6%时,充填体块度变小未对矿石回收效果产生明显影响;而在增大出矿量使贫化率超过10%时,小块充填体的增加对矿石回收效果的劣化影响明显。该结论可为类似矿山在开采过程中控制矿石的贫损提供借鉴。

During the transition from downward slicing cement-filling to sublevel caving without sill pillar in a mine,the caved cement-filling body generated a bulk cover required for the sublevel caving operation.Because of its low intensity,the particle size of fill mass was likely to become smaller as being affected by movement,compaction and friction in the subsequent mining operation,the effect of the above on ore recovery needs to be studied further.The test model was designed at a scale of 1∶100 according to the actual mining levels and drift interval.With dolomite as the run-of-mine ore and iron ore as the filling material,three groups of tests were designed for the cover of filling material with two types of particle size distribution.The particle size distribution of the filling material for tests No.1,No.3 and No.5 was the same as the initially caved ore particle size distribution,while that of tests No.2,No.4 and No.6 was the same as the ore particle size distribution after secondary crushing.All the particle size distribution in the testing ores were the same as the ore from mining site.Ore drawing tests were carried out at mining level of 1,595 m,1,580 m,1,565 m and 1,546 m respectively.The results show that the ore recovery and dilution rate remained basically unchanged after the fill mass became smaller when ore drawing method without ore dilution was employed.When the ore drawing method with low ore dilution rate was applied,although the ore dilution rate went up to 7.6%as the ore production increased,the ore recovery was not affected greatly as the fill mass became smaller.However,only when the increase of ore production resulted in over 10%ore dilution rate,the increase of small particles in fill mass had an obvious negative effect on the ore recovery.This conclusion can be provided as reference for similar mines to control the ore loss and dilution during mining operation.