Yes, the Chinese Bitcoin mine is a security concern. It is located near a Microsoft data center and an Air Force base that controls nuclear missiles. Defense experts have warned that the mine could be used for spying or to disrupt the power grid.

However, the article also states that the mine is owned by a company with an "opaque web of ownership" and is only "linked" to at least one Chinese company. This suggests that it may be difficult to track down the true owners of the mine and to hold them accountable if anything goes wrong.

Ultimately, whether or not the Chinese Bitcoin mine is a legitimate security concern is a matter of opinion. However, it is important to be aware of the potential risks associated with this type of operation.