The first thing that they did after reaching the space near the Mythril golem was to thin out the walls. They chipped away at the walls until they reached about 2–3 meters away from the cavity between the rocks where the golem is.
The space was smaller than they thought, only about 20 meters in diameter. The length of the copper coil that the dwarves made should be more than enough to wrap around it several times.
While the dwarves were setting up the induction forge, the elves were laying down the pipes from a nearby stream towards the entrance to the mine. The pump was set near the entrance so that the dwarves could easily fix it if a malfunction occurred.
After the setup was done, Ein carefully punctured a rectangular hole where the vent would go. The goblins did the same on the other side, making small breathing holes and inlet holes for the water pipe.
The total setup only took about 2 hours, tops.