Description: The SX0-D9 AMD discharge was identified in the 2001 Six Mile, Sandy and Longs Run Watersheds AMD Assessment and Remediation Plan as a significant discharge to the mainstem of Six Mile Run and as a top priority for remediation. Passive treatment of the SX0-D9 discharge utilizing the existing natural iron terrace feature to reduce iron concentrations prior to treatment in the limestone pond followed by a settling pond with an aerobic wetland at the end of the system for final polishing based on the water chemistry.