浅孔留矿法开采倾斜薄矿脉时围岩稳固性研究

Study on surrounding rocks stability of inclined thin ore vein with short-hole shrinkage mining method

浅孔留矿法适用于围岩中等稳固倾斜薄矿脉的开采。云南某金矿矿体赋存条件适合采用浅孔留矿法,但该矿回采指标极不理想。生产实践表明,采场围岩不稳固是造成回采指标不够理想的主要原因之一。为了研究围岩稳固性对回采指标的影响程度,必须研究岩体力学参数取值。运用Flac3D建立多种采场结构参数模型,加载后进行应力应变数据分析,模拟结果显示,在保持原有结构参数不变的条件下,将采场长度由32m增加到40m、顶柱高度由3m增加到5m,采场上下盘围岩在回采和放矿过程中能保持相对稳固。为了进一步证明模拟计算结论的可靠性,该矿就新方案进行了工业试验,结果显示,试验采场回收率达到70.31%,贫化率达到9.80%,与原有方案相比,回采指标有明显改善。可见,采用数值分析法来研究浅孔留矿法围岩稳固性,可以有效提高回采指标。

Short-hole shrinkage mining is adapted to mining the surrounding rock that is moderately stable over the steep or inclined thin veins. A gold ore body in Yunnan is fit for this method, but the ore recovery indicators are not very ideal. Production practices conclude that when using this mining method, the instability of surrounding rock is the main reason of ore great loss. In order to study the extent of mining index impacted by wall rock stability, it＇s necessary to study the mechanics parameters of rock mass and establish some models of various mining structure parameters with Flac3D softwar~ According to the research of stress and strain analysis after loaded, keeping constructor parameters unchanged at the same time, as the stope length increased from 32 m to 40 m and the crown pillar increased from 3 m to 5 m, the surrounding rock of the stope upper and lower sides can still maintain a relatively stable state. In order to prove the reliabili- ty of simulation results, an industrial test is conducted. The test proved that the ore recovery ratio is 70. 31%and the dilu- tion ratio is 9. 80%. Compared with the original scheme, the target is improved significantly. Thus it can be seen that using numeric analysis of rock mechanics to improve the target is an effective method.