1986, Development of irregular plates,  Category I (Calumet and  Hecla Mine General)
name: label: Collection Creator
content: Calumet and Hecla Mining Company.
label: Collection Creator
content: Leavitt, Erasmus D., 1836-1916
setName: label: See more items in
content: Erasmus D. Leavitt Papers
label: See more items in
content: Erasmus D. Leavitt Papers / Series 3: Engineering Drawings
unitdate: label: Date
content: 01/08/1890
container: label: Container
content: Map-folder 34
dataSource: label: Archival Repository
content: Archives Center, National Museum of American History
objectType: label: Type
content: Archival materials