One can also see elevators as self-driving electric vertical motion vehicles. Sure, they are not operating on public roads, and the extra constraints reduce complexity, but they've been around for a while.

Personally, I don't see mining operations as anything remotely close to public roads autonomous vehicles because you have a controlled environment in which paid workers that have been trained to interact with equipment and be aware of its limitations and dangers are performing the said interactions in a strictly constrained manner with the autonomous equipment clearly visible as such and while protected by all kinds of insurance and work-specific regulations.

There's none of that even in the testing stage of current "autonomous" driving vehicles.