Will the new bitcoin-cash be available for mining and if yes, is it mined on new fork that will be submitted or on the previous code?
Yes, it will be available for mining, and you mine it the same way as you mine BTC and, all you need to do is direct your hash power to the pool which will be mining BCC after the split.
ViaBTC provide such a pool for BCC mining and it is available now, https://pool.viabtc.com/pool/bcc/home/