Map of Rolling Mill Mine, Showing the Locomotive Tunnel

The height of the Cambria Iron Company.

This fascinating plan outlines the close relationship shared between the coal and iron industries in Johnstown, Pennsylvania, during the Second Industrial Revolution. Acres of mine workings are shaded with a dull gray, through which solid black and red lines represent the subterranean paths of mule tunnels and modern railway lines. These tracks lead directly to the Cambria Iron and Steel Works, situated on the banks of the Conemaugh River across from the town. A cross-section along the bottom of the sheet presents the depth of the tunnel.

The sheet was drafted by W.A.F. (initialed, lower left) and created by General Mining Engineer John Fulton in 1879. Created for the Cambria Iron Works, a major producer of iron and steel that operated across numerous facilities in the area between 1852 and 1916. This example was published in the 1880 Pennsylvania Annual Report of Mines. Less than a decade after printing, the devastating Johnstown Flood would inundate the town and take the lives of 2,200 residents.