Gated Spawner Drowned Copper Farm in Minecraft

Use zero-based coordinates. Keep the zombie spawner at (5, 10, 5); clear x=1..9, z=1..9, y=8..12 around it.

💡 Find a real zombie dungeon first: spawners cannot be collected or moved in survival. Keep temporary bright lighting while excavating, then remove it only after sealing the chamber. Never break the spawner.

Build the storage platform and 3x3 shaft rings at x=8..10, z=8..10, y=1..6. Use glass at (8, 1, 9) and (10, 2, 9).

💡 The south-facing hoppers at (9, 0, 9) and (9, 0, 10) feed the chest at (9, 0, 11). Keep the glass windows sealed; they let you distinguish green zombies from blue-green drowned without opening the cell. Retain the platform under the east-side lever access. Replace the platform block at (9, 0, 12) with a dry bottom slab; its half-block-lower top is the recessed crouching stance needed to hit above the transport-hopper rim.

Build the room floor at x=1..9, z=1..8, y=7. Build the trench floor at x=1..8, z=9, y=6.

💡 Leave (9, 6, 9) and the shaft above the later roof gate empty for the dry drop. The lower conversion tank is a separate compartment. The trench is one block lower than the main floor.

Build the perimeter walls at x=0, x=10, z=0 and z=10 from y=7 through y=12, then cover y=13 with a solid 11x11 roof.

💡 Cover the roof with bottom slabs at y=14 to prevent outside spawning. Keep all interior light at zero and do not open a window into the spawn room. The modeled roof and walls can replace excavated terrain.

Add the dry shaft signs, upper attack slab, closed roof trapdoor and its east-side lever. Put an east-facing dispenser at (8, 2, 9), with a west-facing wall lever at (7, 2, 9).

💡 Attach the two west-facing signs to the x=10 wall and cap the spawner at (5, 11, 5). The trapdoor is horizontal in the bottom half when closed, hinged on the north side. Put the east-facing wall lever at (11, 3, 9), attached to the solid block at (10, 3, 9): lever on opens the adjacent roof gate; off closes it. Place the dry upper slab before adding water and do not waterlog it: it blocks flow and leaves a gap too short for babies. Keep the full solid block immediately above the slit. Inspect the dry exterior before admitting mobs. The second lever attaches directly to the dispenser: shift-click to place it. These are two independent controls. The east roof lever operates the trapdoor; the west dispenser lever pulses a bucket. Keep both levers off initially and leave the dispenser empty until filling the tank.

Fill the upper conveyor as shown. With the roof closed, place the holding tank's only source at (9, 2, 9), letting it fall through (9, 1, 9). Put that emptied bucket into the dispenser.

💡 Reuse the two water buckets for the nine north sources at x=1..9, y=8, z=1 and the trench source at (1, 7, 9). Use an outside infinite supply to refill. The lower tank must have exactly ONE source, at y=2; do not add a source at y=1 or waterlog any slab, sign, trapdoor or hopper. The y=1 block is falling water supplied from above. After placing the tank source, put its one empty bucket into the side dispenser. Leave the west lever off. Test one off-to-on-to-off pulse: the source should vanish and the lower falling water should drain. A second off-to-on-to-off pulse must restore the top source and refill the tank. Finish with the tank full and both levers off.

With the holding tank full, remove temporary lighting and reseal the spawn room. Switch the east roof lever on, admit roughly 4-8 zombies, then switch it off.

💡 Use a non-Peaceful difficulty with mob spawning enabled. Let each zombie clear the roof before closing: do not close onto a mob occupying the gate. The rendered drowned and queued zombie are illustrative, naturally generated examples. Monitor the queue above the closed gate; it is not an unlimited buffer. Close/open only from outside the shaft. Never allow dozens of mobs to pile up. Check the lower tank is flooded before opening the roof: never drop a batch into a dry cell. The glass wall and dry slab must remain sealed throughout.

Leave the roof closed for at least 60 seconds after the last zombie enters. Inspect the glass window and wait until every mob in the lower cell is drowned.

💡 The closed roof prevents an adult or baby from swimming back up into the dry shaft. Zombies need about 30 seconds with their heads underwater, then about 15 seconds to transform. A green zombie is not ready: do not count its iron/food drops as copper output. If a zombie remains green, stop the next batch and repair the water or gate. Open the roof again only after the lower cell has been cleared. Keep the bucket source in place for this entire wait. Do not drain on a fixed deadline if any target is still a green zombie.

Keep the roof closed. Pulse the west dispenser lever from off to on, then return it to off. Wait for all water to clear and every drowned to settle onto the hopper.

💡 The empty bucket takes the source at (9, 2, 9), storing a water bucket in the dispenser. The single falling block below then disappears. This dry phase prevents converted babies from swimming above the low attack slit and lets dropped items fall into collection. If any water remains, stop and remove the accidental extra source before continuing; do not break a containment wall. Never open the roof in this drained state.