to remove earth that is covering very old objects buried in the ground in order to discover things about the past

Ice age bones are being excavated in the caves. 冰河时期的遗骸正从岩洞中发掘出来。

to dig a hole or channel in the ground, especially with a machine

In tin mining today, workers excavate tunnels horizontally from a vertical shaft. 如今开采锡矿，工人们从竖井中横向开挖隧道。