Granted Patent
Utility
US 4,115,221 · App. 05/772,944
Acid ferric sulfate leaching of copper sulfide concentrates
Inventors:
Milton E. Wadsworth, Jan D. Miller, John A. Herbst, John L. Kolbe, Howard W. Hayden, Jr.
Patented Case
View Patent ↗
Granted: Sep 19, 1978
Filed: Feb 28, 1977
Inventors
Milton E. Wadsworth
Jan D. Miller
John A. Herbst
John L. Kolbe
Howard W. Hayden, Jr.
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.