Charles George Maier, Eugene Delos Gardner, L. C. Ilsley, United States. Bureau of Mines, William Carroll Schroeder, William Waugh Adams, Abraham Albert Berk, Alva Britt Hooker, J. R. Thoenen, L. E. Geyer, M. E. Kolhos, McHenry Mosier, Virginia E. Wrenn, M. G. Parry, S. L. Windes, William Henry Roadstrum · 1940
Arno Carl Fieldner, Carl Edward Julihn, Charles Harold Fisher, George Samuel Rice, William Waugh Adams, Frederick Waters Horton, Irving Hartmann, Joseph Dana Davis, M. E. Kolhos, Virginia E. Wrenn, Walter Alfred Selvig, Reinhardt Thiessen, Dewey A. Reynolds, Clarence Raymond Holmes, George C Sprunk · 1938
Daniel Harrington, McHenry Mosier, William Waugh Adams, United States. Bureau of Mines, Carl Edward Julihn, Jesse Herman Steinmesch, L. E. Geyer, Louise S. Pedlow, M. E. Kolhos, Frederick Waters Horton, Anna Brooke Pleasants Brown, M. G. Parry · 1939
Reginald Scott Dean, Bertrand André Landry, George Stanley Scott, William Waugh Adams, F. J. Kennedy, L. E. Geyer, M. E. Kolhos, P. M. Ambrose, R. E. Swain, Virginia E. Wrenn, M. G. Parry · 1942