n.洞穴探察；崩落开采法；塌落
Caving means exploring the passages underneath the hills. 洞穴探险运动是指探察山中的通道而进行的活动。
Sublevel caving without sill pillar is used in Xishimen Iron Mine. 西石门铁矿采用无底柱分段崩落采矿法开采。
The predicting results can be used as the basis for design and practice of block caving. 预测结果可以作为自然崩落法工程设计与实施的参考依据。
The formation is unstable and the well caving are severe. 地层不稳定，井塌严重。
