What happened after they banned exchanges Binance moved to Malta still it is one of the biggest exchange in the world . Its making lots of progress even still more . If mining reduces in china coins value increase in other place . Because if there is a less mining there will be less supply .
I very much doubt that the Chinese will refuse bitcoin mining. Now China is practically a monopolist in the market. And bitcoin Is the future. I think the Chinese government understands that perfectly well.
I also think that it is almost impossible. Since it was China that gave us the opportunity to use the cryptocurrency as it is now. China has a very cheap labor force. He will definitely come up with something to pay less for electricity.