For the more information about the geologic resources of the National Park Service, please visit

National Capital Regional AML Summary

Geologic Monitoring
Water Tower at Maryland Mine Site, Chesapeake and Ohio Canal National Historical Park, State.

July 2012

The National Capital Region (NCR) has abandoned mineral lands (AML) from historic and past underground and surface mining. Three parks (Chesapeake and Ohio Canal National Historical Park (CHOH), National Capital Parks-East (NACE), and Prince William Forest Park (PRWI) are in the NPS AML database. NCR has had hazards, contaminants, historic features, and threatened and endangered species associated with former gold, iron, lime, and pyrite mines.

Many sites in NCR have been reclaimed such as Cabin Branch at PRWI and Ford Mine in CHOH. Other sites are fenced and or have warning signs to protect visitors and historic features such as the CHOH Maryland Mine. Bat gates have been placed on openings in Maryland Mine and the Round Top Mine, which is used by the federally endangered Indiana bat. In PRWI, the Greenwood Gold Mine had pits filled in 2003-2005 and mercury contaminated soil removed using Repair Rehab fund source. Eight reclamation projects and/or studies were undertaken between 1971 and 1994 at the PRWI Cabin Branch Pyrite Mine site. In 1995, to treat its barren sites, a restoration project at PRWI was funded in part by EPA's Nonpoint Source Pollution Control Program administered by the Virginia Department of Conservation and Recreation's Division of Soil and Water. Community involvement was high, and at the end of the project 150 volunteers gathered at the reclamation site to plant 5,000 native trees and shrubs. The reclamation efforts have negatively impacted the extant foundation ruins of mine structures, however, and these structures require stabilization so that they are not destroyed.

Regional Priorities for Site Restoration


  • Wildlife Issues—NCR has the federally endangered Indiana bat present as well as state-listed bats; these species are a major wildlife concern. With the deadly White Nose Syndrome (WNS) in Round Top Mine complex, we protect and monitor hibernating bats in mine shafts in cooperation with the Maryland Department of Natural Resources. Warning signs about falling rocks are needed at the bat gates. Additionally, there are state-listed invertebrates present.
  • Cultural Resources—Maryland Mine has cultural features that could be restored such as the blacksmith shop and mill. A water tower is intact (Figure 1), but slats are loose, and a tree recently hit and remains on the structure. These structures could be repaired and made safe for visitors. Round Top Mine has 8 lime kilns and a masonry chimney from a historic cement factory. The kilns and chimney need to be stabilized and further interpretation could be provided.

Reclamation vs Restoration

  • NCR would like to mitigate issues and features at sites to remove any hazards to human health and safety. Those that are culturally significant should be restored and interpreted.


Related Links



Last Updated: August 21, 2013