Granted Patent
Utility
US 6,220,167 · App. 09/284,502
Excavation method by blasting
Inventors:
Masaaki Yamamoto, Hidehiro Noda, Koichi Sassa
Patented Case
View Patent ↗
Granted: Apr 24, 2001
Filed: Apr 14, 1999
Inventors
Masaaki Yamamoto
Hidehiro Noda
Koichi Sassa
Assignee (at issue)
ASAHI KASEI KABUSHIKI KAISHA
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.