Progress is saved locally but can also be saved to the cloud for increased security.
Progress can be saved to the cloud by using either Facebook or Google+. (Google+ is only available on Android)
In order to restore the data from a previous Pocket Mine 2 account, the user simply has to log back in using the same credentials.
This feature is located in the option menu, in the Cloud Settings menu.
The user can also manage the save file from this menu.