Abandoned deep mine #29 is the largest contributor to AMD in the Douglas project.  High flows of water from this mine have always been a problem.  The Chief Inspector of the West Virginia Department of Mines observed in his 1904 annual report that “an unusual amount of water is generated at #29, and the drainage is not very good.”  The #29 mine stands adjacent to the old railroad grade and generates a large volume of acid water very close to the North Fork.  The passive treatment system chosen for this project was an experimental design combining an anoxic limestone drain (ALD) and wetland system.  At the time of construction, it was the largest treatment system of its type in the United States.