Question, tell me please if there will be bitcoin split for example is the difficulty of the mining should be changed?
part of difficulty is based on how much hashrate is mining bitcoin or in other words how many miners.
if it splits and the splitted chain (BCC in this case) will obviously won't have enough miners on it. the difficulty will stay the same at first but after reaching the difficulty adjustment block (which is every 2016 block) it will be readjusted) and comes down.
and If there will be 2 coins are the miners that able to mine today bitcoin will able to mine to mine those 2 coins? or there will probably will needed new miner ?
if the new chain doesn't change the way mining works (like changing PoW or other factors influencing it) anyone who was mining before will be able to mine the new chain too but it may not be profitable because of the price of new chain and cost of mining.
in case of BCC this is true. you won't need new miner you can mine with the same ASIC as before.
they can not mine both at the same time though!