As far as cryptsy's mintcoin wallet being in maintenance. it is not an issue with the blockchain but rather an internal issue that effected a few users.
We discovered a bug in security protocol that would see some transactions as unauthorized withdrawals and debit a users account for the amount of the transaction. To prevent any others users from being effected I have taken the wallet offline until the issue can be fixed. This was present in a few coins Saturncoin, Bluecon and Mintcoin.
I am hoping to have the wallet back up within 48 hours. We apologize for the delay it has caused