Skip to content
Patent Leaderboard
USPTO Patent Rankings
Data through Dec 31, 2025
Search
Companies
Universities
Inventors
Cities
States
Technologies
Top Patents
Inventor 500
Select ranking year
All Time
2025
2024
2023
2022
2021
2020
2019
2018
2017
2016
2015
2014
2013
2012
2011
2010
2009
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
1998
1997
1996
1995
1994
1993
1992
1991
1990
1989
1988
1987
1986
1985
1984
1983
1982
1981
1980
Home
›
Communication system for use in a mine
Communication system for use in a mine
US Patent
5504809
· Granted Apr 2, 1996
Estimated economic value:
$52,134,000
ⓘ
Assignee
Placer Dome
Inventors
Frank Chalmers
(1 patents)
Robert Millions
(1 patents)
View full patent text on Google Patents →