Rimfire Minerals Corporation

Rimfire Minerals Corporation

September 13, 2007 20:06 ET

Rimfire Minerals Corporation: Project Update

VANCOUVER, BRITISH COLUMBIA--(Marketwire - Sept. 13, 2007) - David Caulfield, President and CEO of Rimfire Minerals Corporation ("Rimfire") (TSX VENTURE:RFM) is pleased to provide an update on fieldwork undertaken through the summer months. Exploration is underway or has been completed on ten projects in 2007, including projects funded by Rimfire's partners.

Drilling Programs

Drilling continues at the Wernecke (Yukon) and Tide (BC) projects. Wernecke targets include copper-gold +/- uranium and stand alone uranium prospects generated in 2006 and 2007. The program is funded 80% by Fronteer Development Group Inc., with Rimfire funding the remaining 20%. Drilling is expected to continue until early October.

At the Tide Project, American Creek Resources Ltd. is funding and operating a drilling program targeting the 0.5 by 2.0 kilometre Crest gold-arsenic soil geochemical anomaly. This anomaly hosts the 36 Zone where the 2004 discovery drillhole intersected 129.4 metres averaging 1.0 g/t gold, including a 39.2 metre interval averaging 1.9 g/t gold. The primary focus of the program is to expand the 36 Zone and investigate its relationship to nearby surface showings.

A second phase of drilling was recently completed at the California North target in the Goodpaster District of Alaska. Rubicon Minerals drilled three holes to follow up on a 7.4 metre quartz vein intersection that assayed 1.2 g/t gold (see News Release PR07-20, dated August 13, 2007). The follow-up holes were oriented to provide a more appropriate intersection of the vein in order to determine its orientation and true width. Results of the second phase program are expected in late October.

Non-drilling Programs

Fieldwork on a number of early-stage projects in British Columbia and Yukon Territory was undertaken during the summer to evaluate new acquisitions and define potential targets for drilling in 2008. Programs were completed on the PWG, Auddie, Williams and Jake properties and two targets acquired under the Northgate Exploration Alliance.

Work on the PWG, Auddie and Williams projects consisted of mapping, prospecting and geochemical sampling to evaluate new claims acquired prior to the summer field season for their copper-gold porphyry potential. The Williams program is funded by Arcus Development Group Inc. whereas the PWG (near Houston, BC) and Auddie (Quesnel Trough, BC) are Rimfire properties under option from prospectors. Ground-based Induced Polarization (IP) surveys are planned for the Auddie and PWG properties later this fall.

Rimfire recently added to its Quesnel Trough holdings, staking approximately 330 square kilometres of mineral tenure near Fort St. James and Prince George, BC. These claims cover targets thought to be highly prospective for alkaline copper-gold porphyry deposits similar to Galore Creek, Mt. Milligan and Mt. Polley. Geoscience BC is funding a $4.75 million regional airborne electromagnetic (EM) and gravity geophysical survey and a ground geochemical survey in the same area under its mandate to promote exploration in the province of British Columbia through the collection of public geoscience data. Rimfire is planning additional detailed airborne geophysical surveying over its claims to augment the data collected by Geoscience BC.

An Induced Polarization geophysical survey, funded by Island Arc Resources Corporation, was completed on the Jake Property, 13 km west of Clearwater, BC. Work concentrated on the Jake Showing where a 2006 trenching program revealed a mineralized structure with an apparent width of 20 metres. Significant results from the 2006 program included 7.3 g/t gold over 2.67 metres, 6.3 g/t gold over 2.09 metres, 11.4 g/t gold over 0.60 metres and 10.5 g/t gold over 1.00 metre. A 1200 metre trenching program will further investigate the Jake Showing as well as new geophysical targets identified in the 2007 IP survey. The trenching program will start in mid-September followed by drilling in November.

The results contained in this news release have been reviewed by Mark Baknes, M.Sc., P.Geo., Vice President Exploration, a Qualified Person under National Instrument 43-101.

Corporate News

Longview Capital Partners has agreed to an option on a uranium prospect in the Sixtymile River area, Yukon Territory. Under terms of this agreement, Longview may assign the option to another company ("Newco"), whereby Newco would earn a 100% interest in the property by completing $1.5 million in exploration by July 2012 and issuing 1,000,000 shares to Rimfire by July 2011, subject to a 1% NSR held by Rimfire. The claims cover highly anomalous uranium in silt and soil geochemical samples. Eighty-one of the 172 silt samples collected from the property returned uranium values greater than 8.7 ppm (greater than 90th percentile for the entire Yukon regional geochemical survey database), with a maximum value of 350 ppm uranium. The uranium potential was only identified after compiling geochemical data from Rimfire's regional sampling program targeting deposit types other than uranium. For this reason, these anomalies have yet to be followed up nor has a bedrock source been identified.

In keeping with Rimfire's conservative business model, the Company does not invest in asset-backed commercial paper, preferring to safeguard the value of cash by investing in treasury bills and banker's acceptances. These short-term investments are intended to take advantage of higher returns while maintaining the integrity of the principal invested. Rimfire currently has approximately $10.3 million in working capital.

About Rimfire

Rimfire Minerals Corporation is an aggressive, well-financed mineral exploration company with a portfolio of highly prospective gold and silver properties in western North America. Rimfire is partnered with Newmont Mining Company, Northgate Minerals Corporation, Fronteer Development Group, Rubicon Minerals Corporation, Cangold Limited, American Creek Resources Ltd., Island Arc Exploration Corporation, Arcus Development Group Inc. and BWG.

On behalf of Rimfire Minerals Corporation

David A. Caulfield, President

The TSX Venture Exchange has not reviewed and does not accept responsibility for the adequacy or accuracy of this release.

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