Importing unapproved mining equipment sure sounds like an import law violation to me, which would likely be a crime. Revoke Visas and deport them.

The US admin will complain - at which point you can say "revoking Visas and deporting visitors that break the law is a policy idea we got from you".

The truth is that Greenland is in the midst of a mining boom. The Greenland govt wants the mining companies' money, so they won't take strong action against this US mining company - but they also don't want breeches of their sovereignty by ignoring their laws, which is what this US mining company is doing - so they simply complain, issue a stern warning, and hope that 'someone else' will solve the issue for them. Its cowardice.

“A strong warning will be sent to the rights holder with a reprimand stating that all future logistical matters must be notified and approved by the Mineral Resources Authority — before they are carried out,” the ministry said.