Granted Patent
Utility
US 4,389,218 · App. 06/302,827
Production of solid fuel shapes from coal fines
Inventor:
John Pike
Patented Case
View Patent ↗
Granted: Jun 21, 1983
Filed: Sep 16, 1981
Inventor
John Pike
Assignee (at issue)
Blackfire Coal Products
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.