By the analysis of forces, the design principle for indexable drills for shallow holes is put forward. 通过对力的分析,提出了可转位浅孔钻的设计原则。
As a result,the short hole shrinkage method with flat bottom structure was employed to mine the stope firstly,then stoping ore pillar by medium length hole caving method. 后沟金矿采用平底结构浅孔留矿法先采矿房,后用中深孔崩落法回采矿柱,经两年多的生产实践,取得较好的技术经济指标。