Hi There, I'm not that expert in mining or not related to as I don't have that much money to buy powerful ASIC machines to mine bitcoins...
But, according to btcgpu.org Bitcoin Gold is for GPU miners.
and that can really mine a lot of money using GPU's right?
How much money they can make with AMD RX580 8GB? Seems like a noob type question but really interested to know... 
No reals informations about Bitcoin Gold mining.
If Bitcoin gold is GPU mineable, the expected revenue will depends of the numbers of miners and the price of the coin.
Do you have these information ? No.
ou have to wait and see the "D day".
But AMD GPU are bad to mine the expected BTG algo