井下巷道 meaning in Chinese

underworkings

Mine plans ; deep mining ; underground workings ; comments
矿区平面图.深井开采.井下巷道.说明
Probe into the survey method of the underworkings ' section view
井下巷道剖面图测量方法的探讨
Prediction of surrounding rock bearing capability underground roadway
井下巷道围岩承载能力可能性的预测
The development and application of underground roadway waste packing unit
井下巷道矸石充填设备的研制与应用