The Tirex Corporation (TXMC)

[Until2020, formerly Until2017]

YOU ASKED WHEN THE TIREX PATENTS EXPIRE

( At the rate things are going I will expire before a Tirex deal is funded. )

GO HERE : tirex-tcs.com/tech.htm

. . . . . and read this :
-
5- Tirex's "Fracturing Mill" Patents: CDN: # 2,193,334. August 17, 2004;
US: # 5,735,471. April 7, 1998.

Then become a patent expert, because there is not really a single, and easy to understand, rule.

EXAMPLE : http://www.patentlens.net/daisy/patentlens/2981.html

en.wikipedia.org/wiki/Term_of_patent_in_the_United_States

Drug companies ( as an example of the complexity ) have special consideration of time from development through FDA approval till actually on the market.

Additionally, for all patents ( drug and otherwise ), PATENT EXTENSIONS ARE NOT UNUSUAL. A year or two ago, Viagra got a patent extension, which will keep prices higher, longer, sadly.

http://www.uspto.gov/patents/law/patent_term_calculator.jsp

FINALLY THERE IS THE ISSUE OF THE USA and CANADA Patent expirations, since each has a different origination date.

We Tirex share-holders need a patent-lawyer to understand all of this . . .

ONE READ OF ALL THAT IS POSTED ABOVE : 20 years from 1998

( That's just reading the plain English. Experts will have different -- and actually correct -- opinions )

Until2017