**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 ==