=======================================================================
Re:   News Archive - Wednesday, August 20, 2008
      Rimfire/Northgate Make Gold Discovery at Boulevard, Yukon
=======================================================================

PR08--12

Vancouver, BC -- August 20, 2008:  Rimfire Minerals Corporation
("Rimfire") is pleased to announce the discovery of gold mineralization
made during a trenching program conducted with partner Northgate
Minerals Corporation at the Boulevard Property in Yukon Territory. The
Boulevard Property is located approximately 135 kilometres south of
Dawson City, Yukon. Gold bearing mineralization, including 7.04 g/t
gold over 6.0 metres, was encountered in two of three trenches spaced
300 metres apart. A 1000 metre diamond drilling program to test this
new discovery will commence September 1 of this year.

Chip sampling from the first trench (TRBV08-01) yielded 7.04 g/t gold
over 6.0 metres. One hundred metres southeast, trench TRBV08-02
returned 6.43 g/t gold over 2.0 metres. A third trench located 200
metres northwest of trench TRBV08-01 appears to have been located off
trend. Gold mineralization is hosted in strongly sericite-clay altered
schists with disseminated pyrite, arsenopyrite, stibnite and specular
hematite that envelopes quartz and massive stibnite veins. The work
program, completed in July, targeted anomalous arsenic-antimony-gold
soil geochemistry. Additional soil sampling undertaken in conjunction
with trenching has now expanded the target to an area of 2.0 by 0.4
kilometres.

"This mineralization doesn't outcrop. It is a blind discovery that is
the result of solid execution of classic grassroots exploration
techniques," stated Jason Weber, President and CEO of Rimfire Minerals.
"Together with Northgate, we have advanced the Boulevard from concept
to discovery and we now look forward to the September drill program
where we will test the extent of this mineralization."

This program was conducted under an Exploration Alliance with Northgate
signed in December, 2005. This alliance targeted "Pogo-style"
intrusion-related gold deposits in an area fitting the model criteria
and possessing placer gold deposits without a known bedrock source. The
Boulevard area was selected from a much larger regional compilation and
reconnaissance silt sampling program that led to the identification of
anomalous gold and pathfinder elements in creeks draining the
Boulevard. Detailed soil sampling in 2007 outlined the multi-element
geochemical anomaly that was the focus of the recent trenching program.


In light of these positive results, Rimfire and Northgate have added 96
claim units to the property and a follow up program is planned for
early September. This program will consist primarily of diamond
drilling with four to six holes (averaging 150 metres in length) to
test the continuity of the mineralization at depth and on strike. Prior
to drilling, reconnaissance IP geophysical survey lines will be
completed to determine if IP will be an effective targeting tool. As
well, auger soil sampling will be conducted over certain portions of
the existing grid to recover higher quality samples from areas where
permafrost and an ash layer have masked soil geochemical response.

The Boulevard Property is held jointly by Rimfire and Northgate, with
each company having funded the initial $330,000 in exploration that led
to staking of the property. To date, Northgate is has funded
approximately $435,000 of the required $1.5 million in exploration
expenditures to earn an additional 10% interest (for a total of 60%) in
the property.

This news release has been reviewed by Mark Baknes, M.Sc., P.Geo., VP
Exploration of Rimfire Minerals, a Qualified Person for the purpose of
National Instrument 43-101.

About Rimfire

Rimfire Minerals Corporation is an aggressive, well-financed mineral
exploration company with a portfolio of highly prospective gold and
copper properties in western North America and Australia. Rimfire
currently has in excess of two years of operating capital, and finances
approximately 80% of its exploration through option and joint venture
agreements. Current and former partners include AngloGold Ashanti
Limited, Barrick Gold Corporation, Newmont Mining Company, Inmet Mining
Corporation, Northgate Minerals Corporation, Fronteer Development Group
Inc., Rubicon Minerals Corporation, American Creek Resources Ltd.,
Island Arc Exploration Corporation, Jaguar Minerals Limited and BWG.

On behalf of Rimfire Minerals Corporation

"Jason Weber"

Jason Weber, P.Geo., President & CEO

CAUTIONARY STATEMENT:  No stock exchange, securities commission or
other regulatory authority has approved or disapproved the information
contained herein.  This News Release includes certain "forward-looking
statements".  Other than statements of historical fact, all statements
included in this release, including, without limitation, statements
regarding future plans and objectives of Rimfire Minerals Corporation,
are forward-looking statements that involve various risks and
uncertainties.  There can be no assurance that such statements will
prove to be accurate, and actual results and future events could differ
materially from those anticipated in such statements.  Important
factors that could cause actual results to differ materially from
Rimfire's expectations are the risks detailed herein and from time to
time in the filings made by Rimfire Minerals Corporation with
securities regulators.  Those filings can be found on the Internet at
http://www.sedar.com and
http://www.sec.gov/edgar/searchedgar/companysearch.html.

=======================================================================
Copyright (c) 2008 RIMFIRE MINERALS CORPORATION (RFM)  All rights
reserved.  For more information visit our website at
http://www.rimfire.ca/ or send mailto:info@rimfire.ca
Message sent on Wed Aug 20, 2008 at 7:30:28 AM Pacific Time
=======================================================================
.