The Cabin Branch Pyrite Mine began operation in 1889. The American Agriculture Chemical Company took over in 1916 and profited until the mine closed in 1920. Pyrite, known as "fool's gold" due to its gold nugget-like appearance, was valued for its high sulfur content. Sulfur, in the form of sulfuric acid, was used in the production of glass, soap, fertilizer, metal cleaning products, and gunpowder. Because sulfur was in such high demand during World War I, the 200-300 men employed at the mine were exempted from performing active military duty. Today the site consists of approximately 20 acres of historic underground workings, and pyrite foundations and features, tailings piles. During the 1930's, the Civilian Conservation Corps dismantled the remaining structures, using the materials to construct the Cabin Camps.
The Cabin Branch Mine is now considered an abandoned mine site. Many National Park System areas contain abandoned mines. In fact, over 3,000 of these sites are found nationwide in NPS units. Reclamation is a process by which health, safety, and environmental concerns are corrected on previously mined sites. In cooperation with the Virginia Department of Mines, Minerals, and Energy (VA DMME), Prince William Forest Park has begun to reclaim the Cabin Branch Mine. The reclamation phase of the project has addressed such concerns as site safety, severe erosion, and non-point source pollution.
The Cabin Branch Mine Reclamation Plan included the construction of stormwater channels to divert water off of the existing hill slope and tailings piles. Pyrite tailings were removed, placed a distance away from the streambank, limed to reduce acidity, covered with approximately 1 foot of soil and seeded. Material from above the hill slope was brought down to cover the tailings with 1 foot of clean soil. Eight mine shafts were excavated to a depth of 20 feet and capped with cement to create a permanent seal.
The removal of material from the streambank required the installation of a construction fabric for stabilization prior to seeding. The same fabric was used to line the stormwater channels, allowing vegetation to become established and reduce water velocity. This fabric protects the streambank from erosion, while allowing trees and shrubs to be planted at a later date.
The park and the VA DMME have entered into a Memorandum of Agreement to reclaim the Cabin Branch Mine. Recognizing the need to conduct a reclamation project, VA DMME requested a grant through the EPA Non-Point Source Grants Program. EPA awarded $75,000 to VA DMME. The NPS contributed $60,000 and VA DMME contributed the remaining $15,000 to complete the project.
It is important to understand that a reclamation project is not a restoration project. This site will always have an unnatural appearance because of its slope, unnatural flats, undisturbed waste rock piles, and other features. To aid in the restoration of the site, VA DMME has also contributed 4,500 hardwood seedlings. A recent grant from the Virginia Department of Conservation and Recreation for $3,500 has allowed the park to purchase tree shelters and wetland plants to enhance the site. Park neighbors have also been key partners in the completion of this multi-phase project. Planting trees, building trails, and site monitoring have all been accomplished by park volunteers. With their continued support, the pyrite mine site will once again be the most visited site in the park.