I stumbled up on this article about cleaning up Acid Mine Drainage at Wingfield Pines while doing some work related reading. It's located North of Canonsburg, PA, and feeds into Chartiers Creek watershed.
I thought I'd share it since it's a nice caching area with about 10 caches, including a nice earth cache LAND USE GEOLOGY GC34N38 (we didn't do it, as we lacked focus that day and it was raining, but mostly because we lacked focus).
The area had signs that explained what was going on. Also, there was an abandoned and filled in swimming pool, complete with old diving board. So that was cool.