"Underground mines" refers to mine locations that are situated beneath the surface of the Earth. These mines are built underneath the ground to extract valuable minerals, metals, or other resources from deep within the earth. Full definition
The miniature horse was bred originally to work in underground mines, pulling carts. (okcpetsmagazine.com)
The citizens then discovered that the dump contained a 15 - foot - long opening that connected to a maze of underground mine tunnels. (discovermagazine.com)
Conducted research for underground mine studies and construction projects while serving as mining support backup as and when required. (coverlettersandresume.com)