Minecraft wiki entry for Mining, associated text: Another option is the per-chunk branch mine. This is a 2 space branch mine, but is constructed over the space of a single chunk, and is capable of ensuring that every ore deposit is found, while still only mining around 45% of the chunk's stone. For the initial shaft to bedrock for this mine, a 1×2 shaft will fit lengthwise in the central corridor. Also, considering in most cases each chunk have one diamond ore blob, if their only priority is diamonds, they can place the top most branches at level 14 & 15 and dig branches from top to bottom until they strike a diamond blob and then skip the rest of the chunk.