Another Mill Run in Pa. This is a town called Mill Run with a stream near it by the same name. Perhaps this could be the location instead of Altoona. A friend suggested this, "Why would they be using copper tools to mine gold? If it were a coal mine, I could maybe see using copper because of the potential for gas and dust explosions. The only gold I would expect to see in that location would be fool’s gold. The location could very well have an occurance of pyrite. Pyrite looks really pretty in the pan, but it ain’t gold". This would make sense since the Mill Run Pa has coal associated with it but the Altoona location does not.
Mill Run is a section of Altoona. 31st Street turns into Mill Run and ends where it meets Route 36. It does have a stream down through it called Mill Run.
Based on the info, the site appears to be located due west of Mapleton about 1 1/2 to 2 miles near the thousand steps at Jack's Mountain (along SR 22).