Brontosaur Copper Mine Professional Review and Guide
"This short out-and-back ride, past a dinosaur tracking site and an old copper mine, is particularly educational and a treat for anyone interested in paleontology, geology, and mining history. Though the trail is not maintained or marked, it's not particularly difficult to follow.
The trail is a bit technical on the way up, so it's probably not a great place to have the kids on bikes--though as a family hike, it is prime. Blasting caps can still be found in the debris. The caps are small and metallic and can look like a pencil. if they-re old, they can be very volatile due to the degradation of gunpowder into nitro. Don't pick one up! Trail surface: Hardpack, loose sedimentary soils, and bedrock on old 4WD mining road."