RIMFIRE PACIFIC MINING NL - ASX: RIM

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Description

Rimfire is a junior exploration company, focusing on diamond and platinum exploration, and committed to securing and exploring projects with the capacity through discovery to add significant capital value and by extending shareholder wealth.

The Rimfire project and management team has a considerable depth of experience in the identification, procurement and evaluation of exploration and mining tenements across a broad range of commodities. Rimfire will continue to encourage its team to be innovative and prepared to test conventional technical boundaries in minerals exploration.

Bingara - Diamond Project

The highly prospective Bingara-Copeton district has yielded 100's of thousands of diamonds over the last 130 years. To date, no primary source for these diamonds has been discovered.

Rimfire's exploration techniques utilize new high-resolution geophysical imagery, supported by detailed field sampling (stream sediment, bulk and loam) and drilling; together with applying geological concepts derived from cutting edge research by geologists from the NSW Department of Mineral Resources, Australian Museum and Macquarie University.

Rimfire has secured 1100 km2 of highly prospective diamond ground in the Bingara region of New South Wales, near-to the historical alluvial diamond fields. The exploration target is a economic hard-rock source for diamonds mined from alluvial deposits in the area since 1872. Historical estimates by the NSW Department of Mineral Resources places production in excess of 500,000 ct (1 to 2 million diamonds). The stones are of a high quality with one parcel submitted from bulk sampling at the Monte Christo alluvials in 1995, independently valued as 98% gem quality.

The exceptionally large number and high quality of the Bingara diamonds make the primary source a highly attractive exploration target. Previous explorers have included De Beers (Stockdale), CRA and BHP. However without an understanding of the non-kimberlitic origin of the diamonds, or the availability of high-resolution airborne magnetics, their task was formidable and very high risk. The New South Wales Government funded a detailed airborne magnetics program over the region under the Discovery 2000 initiative. This data, combined with the new "Eastern States Subduction Diamond Model", enabled Rimfire to target several prominent circular magnetic anomalies in the region and to secure tenements that cover these features.

The model proposes that diamonds formed in a subduction setting and were entrained at depth by magmas of the Jurassic - Tertiary basaltic pipes and transported rapidly to the surface. There are many areas in the world where diamonds have been discovered in non-cratonic regions, which are also coincident with subduction zones.

Over the years there has been a vigorous debate about the possibility of a primary source of the Bingara-Copeton diamonds. Conventional theorists arguie that such a source cannot exist because the crust is too thin to support temperatures and pressures that could attain the diamond stability field. However, at Penarie, 300 km to the west of Bingara, drilling by RTZ recovered 3 diamonds from a basaltic diatreme*2 which confirmed that in eastern Australia basaltic diatremes are a source rock for diamonds. Furthermore, Rimfire through its exploration efforts has discovered the essential Group 1 eclogite facies garnets and a diamond, more than 20km SW of the alluvial fields, in a stream draining a prominent magnetic anomaly.

Rimfire has secured tenements over several pipes which were previously unidentified on the old, 1 mile flight line, data. The identification of these pipes in proximity to the alluvial diamond fields is considered highly encouraging.

Rimfire has sampled some of the streams draining the identified anomalies. The physical analysis of the grains Rimfire has discovered high sodium eclogitic garnets in streams draining Back Creek and Tom and Jerry Anomalies. In addition, Rimfire has discovered a 0.265ct diamond in a stream draining the Tom and Jerry Anomaly.

The high sodium garnets are shattered, with sharp conchoidal fractures, confirming the material has travelled only a short distance. The occurrence of these obviously locally derived indicator minerals; together with the discovery by Rimfire of a diamond outside the alluvial fields in drainage derived from a magnetic anomaly, proves the [local] source rock contains mantle material which was subject to a temperature and pressure regime required to support the formation of diamonds ("The Diamond Stability Field").

Fifield - Platinum Project

Current exploration interest in the Fifield area follows from Black Range Minerals defining 107 MT @ 0.66% Ni, 0.11% Co*3 (+/- Platinum (Pt) in a lateritic deposit over the Tout ultramafic intrusion at Syerston, an area which adjoins the Rimfire / Black Range JV tenements.

Previous companies, including Helix and Platsearch, had concentrated on exploring for platinum mineralisation. Fifield is the only locality in Australia with records of alluvial platinum mining dating back to the 1880's. The source for the alluvial platinum are several ultramafic intrusive complexes in the region including the Murga Complex which lies within Rimfire's tenements. It is recognised that the style of mineralisation / deposit type is typical of the zoned Ural - Alaskan ultramafics.

Examples of high grade platinum mines of this type of intrusive exist in the Nizhny Tagil Massif in the Urals and Salt Chuck deposit in Alaska (300,000 t @ 26.1 g/t Pt & 14.9 g/t Au ).

The Murga intrusive in Rimfire's tenements is central to the largest "mined" alluvial platinum leads in the Fifield area, (Gillenbine and Platina). Drilling conducted over the Murga intrusive by Austplat and partners in the late 1980's included intercepts of 1m @ 0.93 g/t Pt and 20m @ 0.37 g/t Pt. In addition, Platsearch in the early 90's on the Kars Complex, defined a zone of platinum mineralisation through trenching and drilling which it estimated was 500m long by ~50m wide averaging 0.42g/t platinum which was coincident with a zone of olivine rich rocks (e.g. werhlite, dunite, olivine pyroxenite). Rimfire will apply its consultant's Ural-Alaskan model to these results by utilising magnetics and drilling searching for shoots of ferro-platinum mineralisation within low magnetic targets.

Rimfire's areas also cover the Avondale and Kars intrusives to the south of Fifield, as above. At Avondale a dunite core which is the rock type for laterite Ni-Co has been mapped*4 . Elevated platinum results were also reported over a 2500m X 300m zone. These results Included 8m @ 0.32 g/t Pt from 18m*5. One drill hole noted bluish (? Cobalt) opaline silica in a serpentinite after dunite (SFR 43. 34-35m).

At the Kars Prospect Platsearch defined a 50m wide zone of platinum mineralisation grading approximately 0.45g/t Pt over a strike length of 500m*6. Diamond drill intercepts indicate mineralisation continuing to depth and included;

DDH KD1 40m @ 0.43 g/t Pt with 5.7m @ 1.18 g/t Pt.
DDH KD4 59m @ 0.33 g/t Pt with 1m @ 2.65 g/t Pt.

Mine For

diamonds, gold, copper, platinum, platinum group elements

Location of operation(s)

New South Wales

Address

Room 411 Exchange Tower , 530 Little Collins Street
MELBOURNE, VIC, AUSTRALIA

Phone

(03) 9620 5866

Email

Website

http://www.rimfire.com.au/

Last Updated

10/02/2011