Mineshafts are underground structures in the Overworld made up of interconnected 3×3 corridors with partial rail lines, wooden supports, and cobwebs. They feature wooden bridges or platforms when spanning caves, and may generate near the surface in badlands biomes, where they use dark oak materials. These badlands variants are more exposed and often generate more complete rail lines above ground.

Mineshafts contain various structural elements including a central starting room, supported tunnels, crossings, staircases, and abandoned passageways housing cave spider spawners—a feature unique to Mineshafts. They can intersect caves and aquifers, leading to blocked or suspended corridors supported by logs or chains.

Loot appears in minecarts with chests on rail tracks. Common loot includes rails, torches, coal, iron ingots, seeds, and glow berries. Rarer finds include golden apples, enchanted books, name tags, diamonds, and a small chance for an enchanted golden apple.

Mineshafts can generate large complexes if multiple instances spawn close together. Their mix of loot, traps, and hostile mobs like cave spiders makes them a valuable but risky location for exploration.