An underground worker is someone who works beneath the surface of the Earth. This could include miners, ants, spies, cavers, and coalminers. Miners are people who extract minerals or metals from the ground. Ants are small insects that live in large colonies underground. Spies are people who secretly collect information for governments or other organizations. Cavers explore and study caves and other underground formations. Coalminers are people who extract coal from the ground.