A few years ago, my brother and I noticed a trail of old wood posts leading down the face of a hill in the Eaton Canyon wash. These posts can easily be seen from the Eaton Canyon middle entrance, and lead to what appears to be a concrete and wood structure nestled behind a tree. A few days ago on a Henninger Flat backpacking trip I finally remembered to take some photos and mark it on a map. Maybe it is a mine or maybe even some sort of old telephone pole foundation?
Here is a picture I took from the floor of the wash looking up at the hill. The trail of wooden posts and concrete structure are visible in the upper left.
My guess is that its located at the red marker. It should be accessible via the Wilson Toll road shortcut trail.
In a screenshot from google street view at 213 N Altadena Dr. you can make out the posts across the canyon. If I can get ahold of a decent camera, Ill take some pictures from the road with much better definition.