Mineshafts

A one or two level underground structure that can spawn in any biome.

Mineshaft Corridor

Spawned by carving a cave, decorating the sides with cobblestone and mossy cobblestone, then placing elevated rails and wooden buttresses with lamps. Spawns Chest Minecarts.

Smelting Room

A small room with furnaces and sometimes lamps and chests.

Shaft Room

The room that connects upper and lower levels of Mineshafts. Sometimes, an ore lift will spawn inside it with random ores.

Cave Spider Spawner

An open room with a lot of webbing and one cave spider spawner.

Badlands Mine

Similar to mineshafts, but spawns with a dark oak theme. Badlands mines will have a surface entrance that extrudes out of badlands plateaus. The shaft down from this surface entrance can spawn various ore platforms and one ore lift at the bottom.

The mineshaft at the bottom tends to be smaller.