[Haskell-beginners] Closing a channel

Hi Beginners. I'm trying to implement a program that accumulates a list of items through many IO actions, then use these in another part of the program as a list. I've found Control.Concurrent.Chan which seems to provide a nice abstraction with getChanContents :: Chan a -> IO [a], but there doesn't seem to be a way for the source to close the channel. Are channels the right abstraction for something like this? Should look in to (itter|enumer)at(or|ee)s instead... They seem to encompass this model, but look quite involved.