Restoration Acid Mine Drainage Damage to Dunkard Creek
As described under "Abandoned Mine Impacts", the lower 3 miles of Dunkard Creek are severely impacted by acid mine drainage from abandoned mines.
Some of these AMD sites could be mitigated using Passive Treatment. Passive treatment of coal mine drainage has been shown to be an effective, low-cost, low-maintenance alternative to active treatment at abandoned mine land sites. These passive systems are designed to treat the mine drainage for a long period of time, usually 20 to 40 years.
In 2007, with support of an EPA Targeted Watersheds Grant, the Greene County Watershed Alliance and the Friends of Dunkard Creek sought to reclaim part of the damage by creating a Passive Treatment System, or constructed wetlands, on the Mathews farm near Poland Mines. At this site, the abandoned Maiden #1 mine previously dumped over a million gallons of untreated AMD into Dunkard Creek each day. Working with Stream Restoration, Inc. and public/private partners from across the region, the Alliance created a Passive Treatment System consisting of:
- An aerobic wetland (shallow water flowing over vegetation). Once established, an aerobic wetland produces large amounts of organic debris. The debris encourages anaerobic bacteria, which can revert sulfate ions into sulfide ions. Sulfide ions can then bind with heavy metal ions (such as iron) to remove them from the water.
- Limestone ponds and channels. (Limestone, because of its high calcite content, reduces the acidity of AMD naturally.) When combined with man-made wetlands, it creates a self-renewing Passive Treatment System.
In all, close to 12,000 tons of limestone (equal in weight to 8,000 average-sized cars) were used at the Mathews Restoration Site. Volunteers started more than 2,000 plantings from 34 different species of plants, trees and shrubs. The combination of plantings and engineered flow ponds and channels is a great example of how man and nature can work together to reclaim an area from AMD.
In 2009 as part of an agreement with the PA DEP (PMAP No. 30031601), Dana Mining declared their comitment to mitigate these AMD discharges into Dunkard Creek but as of early 2012, we have seen no evidence of any action on this.