If you have had your coins from before the hard fork that gave us Bitcoin Cash, you have the same amount in Bitcoin Cash (BCH).
Otherwise you'd have to exchange your BTC for BCC and transfer that as payment.
Yes I have the coins before the fork but the value in dollars for each one is different, bitmain is asking for more than 4 BCC, in BTC will be less than one BTC.
I don't see any other way than open a BCC wallet and transfer from the BTC wallet.