Normally miner accounts have a "send threshold" that determines when the bitcoins are transferred to your account. Make sure you have the hit the threshold to have the coins sent to your account before closing the miner account.
There are many strategies for maintaining the integrity and backing up of wallets. I suggest reading around the forums. Much good advice to be found.
My send threshold is set to 1.0 so does this mean my miner has to accrued 1 BTC before I get that into my wallet ? Could take months !