Granted Patent
Utility
US 4,440,450 · App. 06/409,060
Borehole mining valve actuation
Inventor:
John E. Coakley
Patented Case
View Patent ↗
Granted: Apr 3, 1984
Filed: Aug 18, 1982
Inventor
John E. Coakley
Assignee (at issue)
Slurry Mining Engineering Inc.
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.