Code:
on *:text:*:#channel:if $nick = usernick { /timerusernick stop 
/timerusernick $+ # 1 1800  { /ban -u10 #channel usernick
/kick #channel usernick talk instead off lurk an log ffs... } }

so when a usernick speaks 1 line, a counter resets, if he dun talk for 30 minutes after that, the bot kickbans him...

Do-able?

- §CHuTt