Sounds like a national security issue.
But because they just want to relocate the mining farm, they may still be in the US. The first reason why they came to the US was because there was a crackdown in China during that time. Now that China seems to loosen its belt and even approve the ETFs in Hong Kong, I think the miners will likely be going back to China.
If they are currently in the US, that means they are operating under the regulations of the US but not China. If their next relocation site happens to be in China, then there might be a change in regulations which might be far lesser than that of the US.
Though the relocation process would cost alot, as they might have to cease operation for a period of time. But I think operating under a better regulatory agency should be the way forward.