There are a couple more things worth adding about the Champion Spark Plug Mine.
All the maintenance and upgrades are done by volunteers. We found the camp in remarkably good shape, and are actually glad you have to hike in to the camp. While it makes it a lot less convenient to visit, it also means that those who usually ruin it for the rest of us have to work a lot harder to get here. As such, they typically don't get to remote places like the Champion Mine.
For that matter, the 4x4 trails to get to either upper or lower trailhead have their tricky spots. Again, the inexperienced and the uncaring probably won't make it this far.
At the camp, there's one building full of tools and supplies for upgrade or maintenance projects. There's also a list of projects that need attention.
Our sole project for the day was re-tracing the camp's "Welcome" sign, but from the list, it's easy to see there's a lot left to do.
Do you know a prospective Eagle Scout who needs a service project? Do you want to offer some service "just because?" The Champion Spark Plug Mine is a perfect opportunity for such endeavours.