U.S. Steel Duquesne Works, Primary Mill, Along Monongahela River, Duquesne, Allegheny County, PA

See also HAER PA-115 for additional documentation. Includes written data (pages 211 through 226).
Significance: The construction of the Duquesne Steel Works marked an important event in the movement toward integrated steel producing ventures in the Monongahela Valley of western Pennsylvania. Constructed after the Edgar Thomson Works (1875), and the Homestead Works (1884), the Duquesne Works was the site of numerous technological innovations significant in the history of the American steel industry. The mill was the first to employ the "direct process" by which ingots were rolled directly from the soaking pits without being reheated. Under Carnegie Steel a new blast furnace plant was constructed with the industry's first fully mechanized material handling system, an innovation which came to be called the "Duquesne Revolution." For most of its history, Duquesne was a primary producer of semi-finished steel products. In the midst of a declining regional industrial system in the 1960s and 1970s, the mill was shut-down in 1984.
Survey number: HAER PA-115-D
Building/structure dates: 1886 Initial Construction
Building/structure dates: 1900 Subsequent Work
Building/structure dates: 1950 Subsequent Work