It would be extremely dumb for them to do it. consider they are creating tremendous value out of both the mining and the sales / development of mining equipment.
You probably don't know how communism (aka statism) works.
They do such things for displays of power. They rule through terror.
This, communism does not care about such silly things as creating value and free enterprise, they care about power and about showing their citizens they have power over them, to be honest I think miners need to begin to move their operations overseas before the Chinese government does this, it is obvious this is going to cut down their profits margin since electricity in China is very cheap, but it is better to get slightly less profits than to be shut down completely.