{"nrhp_refnum":"02001517","name":"Cabin Branch Pyrite Mine Historic District","other_names":["Dhr #076-0289"],"category":"district","location":{"address":"Prince William Forest Park","address_restricted":false,"city":"Triangle","county":"Prince William County","state":"VA","lat":38.57678345250005,"lon":-77.34904589018655,"geom_source":"nps_gis"},"listed_date":"2002-12-12","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Industry","Historic - Aboriginal"],"significance_levels":["state"],"summary":{"what_it_is":"An 88-acre archaeological and industrial district within Prince William Forest Park near Triangle, Virginia, containing the remains of a pyrite mine worked from 1889 to 1920 along the North Branch of Quantico Creek.","why_significant":"The nomination argues the site is significant under Criteria A and D for its role in the pyrite mining industry, which supplied ore for sulfuric acid, and for its archeological potential. It documents two successive operations, one by the Cabin Branch Mining Company and one by the American Agricultural Chemical Corporation. It also reflects African-American and European-American ethnic heritage among the mine workers.","narrative":"Pyrite, an ore used mainly to make sulfuric acid, was dug from this 88-acre site in what is now Prince William Forest Park between 1889 and 1920. The mine ran in two phases. The Cabin Branch Mining Company, owned by the Detrick and Bradley families, worked the eastern half until 1916, when the American Agricultural Chemical Corporation bought it, built new structures and sank at least one new shaft. Today the eastern side holds the concrete ruins of a commissary, a pony truss bridge, capped shafts and old tailings piles. The wooded western side holds foundations of the crusher house, mill, classifier house, concentrate bin, machine shop, engine room and boiler room, plus a reservoir and traces of rail routes now used as trails. Stone scatters probably mark housing for Black workers. The district was listed for its place in the region's mining industry and for what its remains can still reveal.","period_of_significance":"1889-1920","architect_builder":null,"architectural_style":"No style","criteria":["A","D"],"status_note":"Now part of a public park; shafts were capped and stabilized in a 1995 reclamation project, and a boardwalk was added in 1999. Most structures survive only as foundations and ruins.","vacant_flag":null,"machine_generated":true,"model":"claude-sonnet-5-5","prompt_version":"v1.0-2026-10-29","generated_at":"2026-10-29 02:52:00.726395-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/opastorage/live/55/6827/41682755/content/electronic-records/rg-079/NPS_VA/02001517.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/02001517/44425fec46-800.webp","url_1600":"https://nationalhistoricalregister.com/media/02001517/44425fec46-1600.webp","licence":"Public domain","author":"National Park Service","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:AACA_concentrate_bin_ruins_VA_NPS.jpg\" rel=\"noopener\">National Park Service</a>, Public domain, via Wikimedia Commons","source_page":"https://commons.wikimedia.org/wiki/File:AACA_concentrate_bin_ruins_VA_NPS.jpg"},"district":{"nrhp_refnum":"12000179","name":"Prince William Forest Park Historic District","url":"https://nationalhistoricalregister.com/districts/virginia/prince-william-forest-park-historic-district-12000179/"},"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/41682755","wikipedia":"https://en.wikipedia.org/wiki/Cabin_Branch_Pyrite_Mine_Historic_District","wikidata":"https://www.wikidata.org/wiki/Q15206646"},"indexable":true,"url":"https://nationalhistoricalregister.com/virginia/prince-william-county/cabin-branch-pyrite-mine-historic-district-02001517/"}