Activate [[pickaxe]] '''right click''' any [[cliff]] or [[rock tile]] and select '''mining''' > '''tunnel'''. '''[[Mining warnings|Find potential error messages here.]]'''
*The first step is to make a '''mine entrance''' on the surface which may be done on any [[cliff]] or [[rock tile]].
*The minimum slope of the rock surface to be mined is +1but also have further requirements. The two lowest corners of your tile will form the bottom edge of your opening. If there are not two corners lower than the others (not equal) you cant tunnel. After opening that lower border will be reshaped completely flat at level of the lower corner.*If there are two lower corners identified then the opposite border will be the top of your mine opening and will be completely flat as well. *'''You cannot [[Mining#Surface_mining|surface mine]] to correct an oddly shaped entrance once it is open.''' So you must make sure to have the tile in the exact shape you want it to be before you open the mine.*When tuneling, entrance tile is limited by reinforced cave floor as any others (requires that all four corner of the entrance tile not be also one of a reinforced tile). So, when you are tunneling an entrance from the outside and receive the message, {{event|inline|The ground sounds strangely hollow and brittle. You have to abandon the mining operation.}}, you most likely have a reinforced floor inside the tunnel you are trying to open. Enter the mine from another angle and remove the reinforced floor.*Tunel from outside will ever make a downgoing entrance 20 slope or more, even if there is a flat cave inside. Tunnel out from inside will only remove the rock walls without changing the ground level.*To correct that entry slope you can further raise the mine corner floor with concrete but if ground reach is deep underwater. If you don't want any ugly water on the floor in the mine, ensure that both lower corners of the entrance are at least at height 28 (hover the corner with the mouse).
*Each tunneling action has a chance to create a [[stone shards|stone shard]]. After a number of [[stone shards]] are created, usually 9, the message {{event|inline|You will soon create an entrance}} will appear, after 51 actions. A stone shard or two later, and an entrance will be created.
*The two lowest slopes of your tile will form the bottom tile border of your opening, which will be completely flat. The top of your mine opening will be completely flat as well.
*'''You cannot [[Mining#Surface_mining|surface mine]] to correct an oddly shaped entrance once it is open.''' So you must make sure to have the tile in the exact shape you want it to be before you open the mine.
*If you don't want any ugly water on the floor in the mine, ensure that both lower corners of the entrance are at least at height 28 (hover the corner with the mouse).
*The maximum height of a tunnel entrance is 270 slope, but you would not be able to continue mining because of ceiling height restrictions. Tunnel slopes should be less than 235.
*The maximum height of an tunnel entrance is 90 slope if you plan to add a mine door.
**To widen a tunnel, the tile you mine must only be connected to ONE open tunnel only
** Mine doors can be placed on tunnel entrances that are 1 tile or wider, except on PvP servers. Note that you will need more than one mine door for wider entrances!
* Mine Entrances cannot have a reinforced cave floor. So, when you are tunneling an entrance from the outside and receive the message, {{event|inline|The ground sounds strangely hollow and brittle. You have to abandon the mining operation.}}, you most likely have a reinforced floor inside the tunnel you are trying to open. Enter the mine from another angle and remove the reinforced floor.
== Tunnel excavation ==