I think you can still climb it, the road crosses private land, but eventually gives way to public and the peak is on public land. There signs on the road are more bark than bite, I think if stay on the road in order to access the public land they allow it. We climbed it in spring with no issue and there were people working at the mine road that parallels the road we were on.
If you are worried, contact the mine. I know people who called the mine to find about climbing Bartlett and despite being denied access (they are blasting that peak), the mine personnel were very nice and cordial to talk to you. I am sure they can confirm or deny my assumptions about the road.