It's right around 3pm. Sunset is at 6:30, meaning it will be pretty dark by 7. By Ren's estimation (I'll just lump it in with the previous navigation roll) if you full burn for the mine driving directly there along the road (as long as it lasts), with no stop and no checking things out, driving right up to the entrance would take just over two hours. So you could reach the closest mine just after 5pm with that approach.
If you stop along the way, or take a more cautious approach, it will take longer.