Disabling zeromint will tell your wallet to not mint zerocoins from the coins you receive (by default it would).  You can read much more information on zerocoins, especially anything written by Pivx, to understand more fully what zerocoins are for.  But basically it looks like a transfer of your coins to the zerocoin address; and you end up with an IOU of sorts.  You can then cash in that IOU by telling the zerocoin system to send out your zGMCN to an address.  It is extremely difficult to connect the zerocoin you minted to the zerocoin you spent; promoting significant privacy.