Minecraft: How To Build A Tunnel Bore

While mining is an integral part of Minecraft, it’s also one of the most dangerous. Players will often opt for strip mining instead, as it is much lower risk, but this can be much less exciting and will likely yield fewer resources. Luckily, players have determined how to construct incredibly clever tunnel bore systems, combining TNT duplicators with flying machines to make mining quicker and more fun.

The original design for this tunnel bore was created by Borkon back in Minecraft 1.16, and the machine still works in the 1.19 Wild Update. The machine makes use of TNT duplicators, and while it does take advantage of an in-game glitch, developers have stated that we are likely a while away from seeing them patched, so players don’t need to worry about this machine not working any time soon.

Before starting the build, players should gather all of the necessary resources for it, as well as scout out a location for the bore. Players should head deep underground and mine out a 25-block-long, 12-block-wide, four-block-high area for their tunnel bore. Good starting places would be dripstone caves or other deep, wide-open caves where the player has loads of room to work. When building, it is essential that none of the slime blocks in the build are touching the cave walls or ceiling–that will cause the machine to stall.

As for resources, players will need all of the following:

• Six blocks of ancient debris
• Four shroomlights
• Two blocks TNT
• Two walls (of any kind)
• 21 slime blocks
• Nine pistons
• Eight sticky pistons
• Nine observers
• Seven redstone blocks
• Two detector rails
• Two minecarts
• Two dead coral fans
• Six slabs (of any kind)
• One block of sandstone
• One note block

Start Construction Of The Tunnel Bore

• To begin, players should place three ancient debris in a row, followed by a shroomlight, an observer facing left (and outputting right), then two sticky pistons facing into each other. This row of blocks should have a three-block gap between it and the long side wall, and be parallel to it. The ancient debris can be one block away from the short wall. For players who do not have shroomlights, froglights can be used as an alternative, though that is slightly riskier as they have a lower blast resistance. It appears to work fine, but a bad blast may cause issues.

• Next, with a one-block gap following the piston, construct the mechanism pictured below. It has an observer facing right at piston level, with a dead coral fan placed on top of it. The observer is looking into a wall with the TNT on top of it. There are two upside-down slabs after the wall, one above the TNT, and a shroomlight to the right of the TNT. There is also one slime block above the dead coral fan, and two above the last slab. The wall and dead coral fan here may seem like odd choices, but they are actually the key ingredients in making the duplicator work.

• After that, players will need to load up a detector rail with a minecart on top of the shroomlight. Players must not place the detector rail directly, as doing so would set off the TNT. Instead, players need to place the minecart on a detector rail next to the the shroomlight, then use a piston to push it onto it. They can then destroy the piston system.

• Next, players should place a regular piston behind the two-high slime blocks, in line with the top one, with a one-block gap between them. An observer will output into the back of the piston, facing into a redstone block. Beneath that redstone block, there will be a slime block.

• With all of that done, the first arm of the bore is complete. Repeat this process, constructing the second arm of the bore, which is identical to the first one. The two arms need to have a six-block gap between them, but should otherwise be in line with one another.

• Now, the two arms need to be attached via a slime block system. There should be a two-block gap between the current backmost slime block and the new attachment to the system. Construct it exactly as shown below, with the pistons placed at the same height as the slime block that is two blocks ahead of them. The four pistons facing right here are standard pistons, while the others are all sticky pistons. In the connecting bit of the system, note the one-block gap between the redstone block and the sticky piston.

• Add the button that runs the whole thing to the first arm that was constructed. Note the placement of the back redstone block in this image, and where it is with respect to the sticky piston in the connecting mechanism. To the left of that redstone block is a right-facing sticky piston, then five slime blocks. On top of the slime blocks are two observers facing each other, and a regular piston facing to the left. Beneath the leftmost slime block is a note block, an observer facing right and outputting into sandstone. Above that is a sticky piston and a slime block.

The point of the note block here is to act as a dynamic button. When the note block is interacted with, it will update the pitch it makes, triggering the observer next to it as it notices a block update. This cause the system to activate, but unlike standard buttons, this one can actually be moved by pistons without breaking.

• Finally, it’s time to prime the system. Head to the back left of the machine and place a redstone block on top of the sticky piston facing sideways. After placing it in the spot pictured below and triggering the pistons, destroy it. This will prime the tunnel bore, and it is now ready for action.

How To Use The Tunnel Bore

To use this machine, players need to simply interact with the note block. This will duplicate a TNT block, prime it, and launch it to the end of the ancient debris. Ancient debris is incredibly helpful here, as like obsidian, it cannot be destroyed by TNT. Unlike obsidian, however, it can be moved by pistons. The TNT will explode and mine out a large area, which players can then grab the dropped items from. The machine will also automatically move forward a block when firing.

Players will need to be careful of two things. For one, always wait for the previous TNT to explode before firing another shot. Failing to do so will cause the first TNT to explode and launch the second TNT backwards toward the machine. Next, players will need to manually handle any lava, water, or obsidian that the machine encounters, as none of these things can be destroyed by TNT. The machine will not break when it hits any of these blocks, it will just be unable to progress until they are removed.

If players want to increase efficiency even more, they can build a mirrored tunnel bore to the left of this one, each with a separate button system. By walking between the two, players can operate both at once and double the rate at which they gather resources. Just be careful to make sure that there is exactly a six-block gap between the ancient debris of one machine, and the ancient debris of the other.