Keywords: "Six Companies' high level concrete mixing plant and cement blending plant." - NARA - 293893.jpg Scope and content Photograph from Volume Two of a series of photo albums documenting the construction of Hoover Dam Boulder City Nevada General notes 293893 Local identifier Department of the Interior Bureau of Reclamation Engineering and Research Center 05/18/1981 - 03/04/1988 NARA's Rocky Mountain Region Denver NRGA Building 48 Denver Federal Center West 6th Avenue and Kipling Street Denver CO 80225-0307 1933-06-23 Record group Record Group 115 Records of the Bureau of Reclamation 1889 - 2008 Record group ARC 444 Photograph albums compiled 1903 - 1972 Series ARC 293611 File unit File unit ARC Variant control numbers NAIL Control Number NRG-115-CONSTPHO85006-BC21788 Other versions <gallery> File Six_Companies'_high_level_concrete_mixing_plant_and_cement_blending_plant _-_NARA_-_293893 tif tif File Six_Companies'_high_level_concrete_mixing_plant_and_cement_blending_plant _-_NARA_-_293893 jpg jpg </gallery> NARA-cooperation PD-USGov Six Companies Inc concrete mixing plants at Hoover Dam construction site high level Six Companies Inc cableways at Hoover Dam construction site |