well

A well is a shaft drilled, bored, or dug into the earth for the extraction of water, oil, natural gas, or another liquid, gas, or viscous substance. The shaft may be vertical, diagonal, angled, bent, or forked.

The shaft provides access to material below the surface. It can change direction or branch rather than being a straight vertical hole.

A wide open pit and a network of mining cavities have different excavated forms. The well is specifically the extraction shaft described above.