The mineshaft was so deep that workers had to take an elevator to reach the bottom.

mineshaft 是由 mine（矿）和 shaft（竖井、通道）组成的复合词，字面意思是"矿井的竖井"，指矿井中垂直或倾斜的深井通道，用于人员、设备或矿石的运输。