medium length hole

• 中深孔

medium length hole的用法和样例：

例句

1. Test Research on Parameter Optimization for Long and Medium Hole Drilling and Blasting in Sanxin Co.
   三鑫公司中深孔凿岩爆破参数优化与试验研究。
2. 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。