回挖 meaning in Chinese

back cutting

They had a smoke and a chat in the shade , and then dug a little in their last hole , not with great hope , but merely because tom said there were so many cases where people had given up a treasure after getting down within six inches of it , and then somebody else had come along and turned it up with a single thrust of a shovel
他俩先在树荫下抽了一会烟，聊了几句，然后又在剩下的一个洞里继续挖了几锹。当然这样做并非出于抱有多大的希望，只是因为汤姆说过有许多回挖宝的人离宝只有六寸，结果还是让别的人一锹就给挖走了。