Mineshaft



Abandoned Mine Shafts are a type of structure added in Beta 1.8, along with Strongholds and NPC Villages.

Structure
Abandoned Mine Shafts are a series of straight intersecting tunnels 3 blocks wide. They have uneven ceilings with a height of 2-3 blocks. Wooden planks and Fences make up the supports of these tunnels. Incomplete sections of minecart tracks can be found at the floor of these shafts and torches are occasionally placed on walls. Cobwebs are placed at random within. Large, collective masses of cobwebs harbor Cave Spider spawners. Occasionally, stair-like tunnels can be found.

Cave Spiders are exclusive to these areas. There are chests spread throughout the mine that contain resources such as Gold and Iron ingots, ores, food, or seeds. They may even contain diamonds or pickaxes. It is possible (but rare) to have one spawn in an Ocean Biome, causing the shaft to be flooded. Abandoned Mine Shafts are also rich with ores such as Iron, Gold, and rarely Lapis Lazuli and/or Diamonds. As the 'shafts' are made of Wooden Planks, Abandoned Mine Shafts provide very good source of wood while prospecting underground.


 * Obtainable items:
 * Diamond
 * Coal
 * Lapis Lazuli
 * Redstone Dust
 * Iron Ingot
 * Gold Ingot
 * Melon seeds
 * Pumpkin Seeds
 * Wheat
 * Bread
 * Rails
 * Iron Pickaxe
 * Golden Apple
 * Wood planks
 * Fences
 * String

Exploration
The easiest way to find mine shafts is to find a Ravine. It is likely that a mineshaft will intersect it. In ocean biomes, it may also be possible to find a upper part of the shaft complex exposed to water at some of the sections.

Abandoned Mine Shafts may be large and be akin to labyrinths, making it difficult to keep bearings. The venomous Cave Spiders are very common and make exploration dangerous unless prepared. However, due to automatically placed torches, the presence of other mobs is much lower, making areas aside from the Spider spawners safer than caves. Gravel sometimes collapses into shafts, making them appear dead ends. Dig a few blocks past gravel walls to check if the shaft continues or not.

Using large amount of resources found in Abandoned Mine Shafts, the player may cut down cobwebs, take out wood from the supports, and create a safe room with a bed within the shafts to work out of. This makes exploration easier, although becoming lost means losing resources within the room and possibly death from the Cave Spiders or other hazards within the elaborate structure. One should put caution before anything else when exploring these locations.

Glitches
x: 279 y: 25 z: -501
 * Due to a world generation glitch, parts of the Abandoned Mineshafts may be floating in the area. This is most noticeable when an Abandoned Mine Shaft intersects an underground ravine, where as the wooden supports for shafts can be found floating. Chests and Minecart tracks are also included in this.
 * If a Dungeon and an Abandoned Mine Shaft is being generated together it may make the drops from the chests lay around like the chests in the Dungeon or Mine Shaft has been destroyed by a player and not picked up the drops. The seed: "When Pigs Fly" (1274876030) has an example of this on the coordinates:
 * When the Mineshafts are being generated, there is likely to be a spot where two shafts are generated on top of each other creating a very annoying obstacle if you are attempting to traverse the top shaft.

Trivia

 * In the 1.8 Pre-Release 1 and 2, support beams in mines were only made of planks. Fences were added later in the 1.8 version.
 * Some spots in/around the mine shafts have been known to have a strange terrain generation that causes a random 'room' in the mine with a dirt flooring, usually fairly large, with no observable purpose. These are much like circular chambers in cave systems from the generation code. Whether this is a bug or intended is unknown. Some reports have shown that sometimes even Cave Spider Spawners make up the Ceilings of these rooms, so be very careful when exploring these rooms in Easy or above.
 * In 1.9 prerelease 2, players can hear strange noises in mineshafts.
 * Logically, it is unknown why these mine shafts are ore-rich, since abandonments of such shafts are where the rock is poor in ore, or the ore has been exhausted. It makes sense for ores in the shaft to be deleted during terrain generation, rather than multiplied. That said, it is plausible that a reason other than ore-depletion produced the abandonment.