I had a chance to drive down Gum Springs the other day and was amazed at all the construction going on down there. They've cleared out huge areas of land for house and apparently a big expansion of the Bull Run Quarry site.
I wasn't even aware that there was a quarry there, but apparently it's going to get get a lot bigger. They're even going to move Gum Springs road over so they can pull the stone out from beneath the current road. I guess the people who live down there are aware....
http://bullrun.luckstone.com/
http://bullrun.luckstone.com/maps.cfm