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Rimfire Portfolio - Goodpaster, Alaska

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A New Gold District in North America

• Large, strategically located land position in an emerging gold district.

• Two areas of drilling in previous years returned high grade gold mineralization in narrow, vertical quartz veins, resembling "halo veins" associated with the ore bodies at Pogo.

• Strong partner with the vision and the access to capital to effectively advance the Goodpaster District properties.

• 2007 program included drilling of newly defined and existing gold targets on the properties.

In 2008, Rubicon is funding a field program to examine areas of the property that have yet to be explored systematically. This will be followed by drilling in late July or early August.

This follows the 2007 program, in which Rubicon funded a $1 million program, consisting of drilling three new widely-spaced targets and a fourth-hole at the Boundary Zone, a target which had seen previous drilling (3 of 5 holes in 2000 and 2001 yielded visible gold in narrow quartz veins).

On August 13, 2007, the results of the four-hole drill program and accompanying surface work were released. The first drill-hole, CN07-01, drilled at the California North Target of the Cal-Surf Property, intersected a significant quartz vein which averaged 1.2 g/t gold over 7.4 metres. This intersection is significant for the following reasons:

1. This is the first thick vein intersected in drilling on the Cal-Surf Property. It demonstrates that the geological conditions conducive to producing a thick quartz vein were present at California North.
   
   
2. The fact that it carries gold is encouraging, indicating that the hydrothermal fluids that formed these veins were gold-bearing. These two points are significant in that the exploration target in this district is thick, high-grade gold-bearing quartz-veins similar to those being mined at the Pogo Deposit 20 km to the east.
   
   

Core recovery was very poor through the intersection (>70% of the core was recovered, on average) and the vein margins were not preserved, making an estimate of the true thickness of the vein extremely difficult. Rubicon is funding at least one follow-up hole targeting the California North vein to help determine its orientation and measure its true thickness. Additional surface work will be undertaken in conjunction with drilling. It is expected this work will start in mid-August.

Surface work carried out at the Eagle, Swede and Cal-Surf properties identified new areas of anomalous gold and pathfinder element geochemistry that warrants further investigation.


Intrusive-related high grade gold vein targets are characterized by thick, high-grade gold-bearing quartz veins. These deposits show a characteristic metal signature of gold-bismuth-arsenic and an association with granitic intrusions. An example of this type of deposit is the Pogo gold deposit Teck/Sumitomo which has a published combined reserve and geological resource totaling 4.5 million contained ounces of gold. Rimfire has no direct or indirect interest in the Pogo Deposit.

Rimfire selected claims in the vicinity of and adjacent to the Pogo property based on regional geological, geophysical and geochemical similarities to Pogo. Recent gold discoveries in the district and the commencement of gold production at Pogo led Rimfire to expand its holdings in this emerging gold belt in late 2005.


Rimfire Controls 740 sq km

Rimfire properties lie adjacent to and in the vicinity of the Pogo deposit, which is located 55 km (34 mi) northeast of Delta Junction in east-central Alaska. Teck/Sumitomo has built a road to the Pogo Mine site, which passes close to some of the company's properties, but access is currently available by helicopter from Delta Junction.

Rimfire controls the largest land package in the immediate Pogo area, with 740 square kilometres (182,800 acres) of wholly-owned State mining claims.

Rubicon Minerals, through its acquisition of the Alaskan assets of Robert McEwen's Evanachan Limited, is funding US$4.8 million in exploration over six years to earn a 60% interest in Rimfire's claim package. Evanachan's assets included its Option on Rimfire's land package. Rubicon acquired the Evanachan assets for $22 million in shares, giving Robert McEwen a 33% interest in Rubicon. After earning a 60% interest, Rubicon can earn an additional 10% by completing a feasibility study.


Claims adjacent and on trend with Tech/Sumitomo's Pogo Deposit

The Rimfire's properties lie adjacent to and in the vicinity of the Pogo deposit, which is located 55 km (34 mi) northeast of Delta Junction in east-central Alaska. Teck/Sumitomo has built a road to the Pogo Minesite, which passess close to some Rimfire's properties, but access is currently available by helicopter from Delta Junction.


In 1998, Rimfire acquired an extensive land position in the Pogo area. Specific targets were identified on the basis of a comprehensive compilation and geologic interpretation. Subsequently, joint venture partners Western Keltic/Barrick Gold, Hyder Gold and AngloGold have spent in excess of $4.5 million (Cdn) on surface exploration and drilling. In anticipation of the startup of production at Pogo and a significant nearby discovery made by AngloGold, Rimfire has aggressively acquired ground based on a renewed understanding of the critical controls on mineralization.

• ER
  
  AngloGold conducted 3158 m in drilling in 2003/04 to test a gold (>25ppb) arsenic-bismuth-antimony soil anomaly, measuring 1500m x 300m on the ER property. Holes cut widespread alteration enveloping multiple quartz-sulphide veins and vein breccias, some containing visible gold. Results included 3.9 metres of 1.10 g/t Au in ER03-1 and 0.5 m of 63.1 g/t Au. Several features encountered in the drilling indicate a system losely related to that found at Pogo.

• Eagle
  
  At the Eagle Property, AngloGold conducted drilling totaling 2778 m testing portions of a 2.0 x 0.5 km gold-arsenic-bismuth-antimony-tungsten soil anomaly in an area of virtually no outcrop exposure. Drilling followed up a 2000 intersection of 18.7 m of 0.44 g/t Au. Gold-bearing stockwork mineralization and alteration is present in all the 2004 holes. Future work will focus on identifying structural and potentially high grade controls to mineralization.

• Boundary and SE Surf
  
  Gold-bearing surface mineralization discovered at the Boundary and SE Surf zones, has returned assays up to 24.8 g/t (0.72 oz/ton) gold. Mineralization is associated with kilometre-scale gold, bismuth, arsenic soil anomalies. 2000 drilling by Barrick at the Boundary Zone intersected visible gold in 3 of 4 holes that occurs in sheeted 1-5 cm quartz-pyrite-pyrrhotite-bismuthinite veinlets. Similar sheeted veinlets at the Pogo Deposit and nearby "Hill 4021" Zones (also on the Pogo Property) occur as haloes about ore-bearing structures. Distinctive biotite-bearing shear veins at the Daydreamer occurrence are strikingly similar to those within the Pogo Deposit where they are interpreted as precursors to ore veins. Numerous geochemical and geophysical targets have yet to be evaluated by detailed surface work or drilling.