Hm, okay. That does seem to indicate digging and building is actually possible. Thanks.
It's almost like the game that looks like Terraria, has mechanics like Terraria, has been shown to play like Terraria, has had screenshots that indicate Terraria-like gameplay and is headed by one of the people who worked on Terraria... is LIKE TERRARIA. Heaven forbid.
Seriously, a bit of skepticism is good every now and again, but there comes a line between skepticism and violating common sense with a rake.
There is a fair chance that the whole "mining station" thing will be in the game, considering the NPCs and structures. It seems fairly likely that you'll be able to delegate the resource harvesting to NPCs to some degree. Maybe it'll have a radius, within which resources can be harvested by the station, or maybe you could use special markers of some kind to designate a vertical harvesting area, within which resources would slowly be replaced by regular stone and added to the station's internal storage. The rate could depend on the NPCs manning the station. The station would remain active while on other worlds until it ran dry at its' normal rate (either on a timer or ore/minute, with each ore being brought in at different rates (perhaps common ores could have a minmum rate of 1 per 2 minutes, up to rare ores at a minimum rate of 1 per 20 minutes), at which point you would get a notification of some description.