Dig Into Mountain
Dig into Mountain is a command that players can give to citizens to cut into the tiles of a mountain. Each tile of a mountain can provide 1 stone. This is a helpful command if players decide to want to build inside the interior of a mountain, or reach ore or stone deposits inside them.
The opposite of this command would be Refill mountain cave, which revert mountains back to their uncarved forms at the cost of 2 stone per tile.
In-game description
"Digs a tunnel into the mountain."