{"nrhp_refnum":"74001741","name":"Main Building, U.S. Bureau of Mines","other_names":["Pittsburgh Experiment Station, U.S. Bureau of Mines, Buildin"],"category":"building","location":{"address":"4800 Forbes Ave.","address_restricted":false,"city":"Pittsburgh","county":"Allegheny County","state":"PA","lat":40.44414743900006,"lon":-79.94573595499998,"geom_source":"nps_gis"},"listed_date":"1974-05-24","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Architecture"],"significance_levels":["national"],"summary":{"what_it_is":"The Main Building (Building A) of the U.S. Bureau of Mines at 4800 Forbes Avenue in Pittsburgh, Allegheny County, Pennsylvania, part of the Pittsburgh Experiment Station. Construction began in October 1915 and was completed in September 1917, with dedication on September 29, 1919.","why_significant":"The building is nominated for its architecture only. It is presented as an example of Henry Hornbostel's work, which blends neo-Renaissance Beaux-Arts tradition with the functional demands of a technical institution. The powerhouse is cited as showing early architectural Modernism while still shaped by Classical layout.","narrative":"Built between 1915 and 1917 at 4800 Forbes Avenue in Pittsburgh, the Bureau of Mines Main Building was designed by Henry Hornbostel, with the New York firm of Palmer and Hornbostel named as architects of record. It combines the neo-Renaissance pavilion forms of the Ecole des Beaux-Arts with the utilitarian requirements of a technical research institution. Its design is linked to Hornbostel's work at the Carnegie Institute of Technology, and it shares the Carnegie campus's stark brick interiors and exposed pipe railings. The adjoining powerhouse, built in 1918 with a pair of smoke stacks, is regarded as showing an emerging Modernism that remains shaped by Classical layout. The building was dedicated on September 29, 1919. Its significance rests on its architecture, specifically the way Hornbostel handled new industrial functions within an established Classical framework.","period_of_significance":"1915-1917","architect_builder":"Palmer and Hornbostel (architects of record); Henry Hornbostel (architect of the group of buildings)","architectural_style":"Neo-Renaissance, Beaux-Arts influenced","criteria":["C"],"status_note":null,"vacant_flag":null,"machine_generated":true,"model":"claude-haiku-5-5","prompt_version":"v1.1-2026-10-29","generated_at":"2026-10-29 17:11:29.036676-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/lz/electronic-records/rg-079/NPS_PA/74001741.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/74001741/9dbcdb3877-800.webp","url_1600":"https://nationalhistoricalregister.com/media/74001741/9dbcdb3877-1600.webp","licence":"Public domain","author":"Nyttend","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:Main_Building,_U.S._Bureau_of_Mines.jpg\" rel=\"noopener\">Nyttend</a>, Public domain, via Wikimedia Commons","source_page":"https://commons.wikimedia.org/wiki/File:Main_Building,_U.S._Bureau_of_Mines.jpg"},"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/71997624","wikipedia":"https://en.wikipedia.org/wiki/Main_Building,_U.S._Bureau_of_Mines","wikidata":"https://www.wikidata.org/wiki/Q6735938"},"indexable":true,"url":"https://nationalhistoricalregister.com/pennsylvania/allegheny-county/main-building-u-s-bureau-of-mines-74001741/"}