LR The main mine shaft, which goes down 45 feet on an incline, has been caged over to keep out visitors who don't think the rules apply to them. A few years ago Joshua Tree had a problem with visitors taking home artifacts from mining sites. The park had to remove any all loose mining items from the abandoned mines to preserve them.

I found another hiker's trip report with pics and the upper and LL pics show that this was not fixed up yet. So the repair work is fairly recent.