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.