I googled this search string, exactly as you see it inside the brackets: ["Crown Hill Mesa" +Colorado +mining] and got quite a few hits.
This is the Urban Renewal Plan for the area, with map on page 10, and it sure looks like this is the mountain of mine tailings that they plan to somehow make livable....I believe with an earthen cap about six feet deep. Right now, nothing grows on that stuff, just pulverized rock and not amenable to plant life. A good realtor will know for sure.
http://www.springsgov.com/units/Plan.../GHMURPLAN.pdf