Refill mountain cave
Refill mountain cave is a command that players can give to citizens, in which it can have them revert a carved mountain tile back to its original filled, rocky and path-obstructing form. Every tile filled will cost the player 2 stone.
This can only be performed on mountain tiles that were dug out by the Dig Into Mountain command.
In-game description
"Refills dug tunnels or natural mountain caves."