What happens to bitcoins that get sent to an expired address? Can these still be recovered?
Not if they've been actually sent. You'd have to hope Mt Gox hasn't actually processed the withdrawal yet, and try to get them to cancel it. (good luck!)
It's not been processed as it never turned up. I told them to cancel it but I doubt they will.
As far as I'm concerned, it's still their liability.
I'm just giving them time to sort themselves out and see if they'll make good of the situation.
So far it's been pretty unprofessional.