A massive rock fall trapped the men as they operated a tunnelling machine.一块坠落的巨石困住了操作隧道挖掘机的工人。They were tunnelling into the mountainside.他们正在山腰上挖隧道。The workers were tunnelling through solid rock.工人们正在坚石中挖掘一条通道。One person suggested tunnelling under the walls.有人建议在墙下面挖地道。