- Published: 11 February 2009
- Written by Editor
Colossus Minerals Assays 7.88 Metres @ 98.4 g/t Platinum, 115.7 g/t Palladium, 2.74 g/t Rhodium, 1.52 g/t Iridium and 406 g/t Gold From Serra Pelada
Colossus Minerals Inc. ("Colossus") (TSX: CSI) is pleased to announce results for the first systematic assaying of drill core for the complete platinum group element (PGE) suite from the Serra Pelada Project, the Colossus-COOMIGASP joint venture located in Para State, Brazil.
HIGHLIGHTS
- Systematic sampling and assaying of drill core from the Central
Mineralised Zone at Serra Pelada has yielded platinum (up to 299 g/t),
palladium (up to 387 g/t) rhodium (up to 7.7 g/t) and iridium (up to
4.9 g/t), grades among the highest on record
- High grade PGE-gold intervals include FD-072:
7.88 metres @ 406.4 g/t gold, 98.4 g/t platinum , 115.7 g/t palladium,
2.74g/t rhodium, 1.52g/t iridium, 0.19g/t ruthenium and 0.03g/t osmium
including
1.87 metres @ 1431.3 g/t gold, 248 g/t platinum , 321.4 g/t palladium,
6.50 g/t rhodium, 4.21g/t iridium, 0.39g/t ruthenium and 0.10g/t osmium
- Platinum to rhodium ratio varies systematically with the gold to platinum
ratio, ranging from around 10:1 to over 40:1. In this range, rhodium
values will contribute significantly to the value of high PGE subzones at
Serra Pelada
- The assay data indicate high PGE subzones in more southerly parts of the
Central Mineralised Zone, where Colossus has only conducted limited
drilling to date and also the possible continuity of a high Au-PGE subzone
over 200 metres strike length.
DETAILS
Core samples from seven drill-holes representing 128 metres of down-hole intersections in the Central Mineralised zone were fire assayed for gold, platinum, palladium, rhodium, iridium, ruthenium and osmium by PGE specialist Genalysis Ltd., Perth, Australia. These data are the first systematic assays for the full PGE suite at Serra Pelada. A summary of core sampling, sample types, analytical methods and QA/QC measures is given in TECHNICAL INFORMATION, below.
Some extraordinarily high gold and PGE assays were encountered over metre core lengths. These values include platinum (up to 299 g/t), palladium (up to 387 g/t) rhodium (up to 7.7 g/t) and iridium (up to 4.9 g/t), grades among the highest on record.
Significant assays for continuous intervals of Au-PGE mineralisation are presented in the following table:
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Inter- Gold Plat- Palla- Ruth-
From val(i) (ii) inum dium Rhodium Iridium enium Osmium
Drillhole (metres) (metres) g/t g/t g/t g/t g/t g/t g/t
----------------------------------------------------------------------------
FD-072 251.79 13.71 204.5 58.6 69.2 1.61 0.90 0.11 0.02
including 251.79 7.88 406.4 98.4 115.7 2.74 1.52 0.19 0.03
256.85 1.87 1431 248 321.4 6.50 4.21 0.39 0.10
----------------------------------------------------------------------------
less
than
FD-058A 230.04 1.91 169.1 13.64 18.99 0.43 0.59 0.03 0.02
less
than
and 277.58 8.93 9.62 6.11 6.68 0.21 0.12 0.02 0.02
----------------------------------------------------------------------------
less
than
FD-062 273.74 3.06 115.9 35.57 46.12 1.33 0.75 0.11 0.02
----------------------------------------------------------------------------
less
than
FD-104 274.4 7.50 27.73 9.68 6.62 0.41 0.14 0.03 0.02
----------------------------------------------------------------------------
(i) True thickness not known
(ii) Gold and PGE fire assays using NiS collector material
These drill-holes are from more southerly sections of the Central Mineralised Zone, where Colossus has undertaken limited drilling to date. The assayed intervals apparently represent high-PGE subzones that warrant further drilling to establish continuity. Platinum/palladium ratios are also higher than expected from historical data for these subzones. The high Au-PGE subzone in FD-072 may prove to be continuous with those so far encountered in Colossus Phase I drilling in the upper and outer fold hinge, up to 200 metres to the northeast.
Over the entire assay dataset platinum /rhodium ratios vary from around 10 to over 40. In this range rhodium values will contribute significantly to the value of high PGE subzones at Serra Pelada and less so to high Au/PGE subzones, although the latter (eg. FD-062) may exhibit higher iridium values. Colossus will undertake further systematic PGE assays over a broader geographic range and to clarify the distribution of PGE in different alteration types in the Central-and other mineralised zones.
Vic Wall, Colossus President, comments "The Au-PGE assay results would be extraordinary anywhere other than Serra Pelada. Colossus' work continues to add value to the Serra Pelada treasure chest, demonstrating that PGE's will contribute significantly to the worth of this remarkable deposit."
ABOUT RHODIUM AND IRIDIUM
Rhodium is a rare, silvery-white, hard transition metal and a member of the platinum group. Rhodium is found in platinum ores and is used in alloys with platinum and as a catalyst. (Source: Wikipedia). After trading as high as US$10,000 per ounce in 2008, rhodium is presently trades at approximately US$1300 per ounce.
Iridium is a very hard, brittle, silvery-white transition metal of the platinum group, is the second densest element and is the most corrosion-resistant metal, even at temperatures as high as 2000 degrees C (Source: Wikipedia). Iridium currently trades at approximately US$425 per ounce.
TECHNICAL INFORMATION
Sampling of historical Vale core (by Colossus personnel) and sample preparation (by SGS GEOSOL LABORATORIES LTDA., Belo Horizonte) were carried out under strict protocols as recommended in the 43-101 Technical Report on Serra Pelada and independently by Pitard (2007). After photographing and logging, nominal 1 metre intervals of remaining half core were completely removed yielding samples of up to 2 to 3 kilogram mass. Where core recoveries were low, intervals were composited to yield approximately 1 kilogram minimum sample masses.
A range of sample types were submitted to Genalysis Ltd., Perth Laboratory. Where possible these included splits of rejects from coarse crushes, non-subsampled and previously sampled pulps, Duplicates, blanks and certified gold-PGE reference materials were inserted in the sample train by Colossus personnel prior to secure shipping to SGS. Genalysis inserted other Au and PGE reference materials in all batches.
Genalysis performed screen fire assays (AAS & MS finishes, Pb collecter) on the pulverised rejects (greater than 95% passing 106 microns) from the crushed (greater than 95% passing 1.7mm), dried samples. Pulps were re-homogenized and fire-assayed for Au-Pt-Pd utilising 50 g or 25 g aliquots and Pb collectors and also for Au and the complete PGE suite utilising 25g aliquots and NiS collector materials. Additional blanks and duplicates were inserted in the assay streams by Genalysis and replicate assays were performed every twenty samples. Genalysis dispatched assay certificate originals directly to Resource and Exploration Mapping Ltd. an independent Company which manages Colossus' database.
The Genalysis assay results for blanks, duplicates and replicates were generally satisfactory. However unacceptably high Au-(Pt-Pd) values were noted in some quartz washes of pulveriser-homogenizer vessels. These values appear to have resulted from over-grinding and smearing of noble metal particles on vessel walls. Genalysis advises that some Au-Pt-Pd assays should be regarded as low due to these effects, but mass balances and additional check assays indicate that effects on grade and possible carryover between samples were generally within analytical uncertainties.
Genalysis assay results of certified Au-PGE reference materials were generally within accepted ranges for these materials. The results from different methods of fire assays were consistent within assay uncertainties. For the internal consistency assays utilised in this release were 25gm sample fire assays utilising NiS collector for Au and the PGE-suite. Screen fire and multi-element assays performed on the sample batches will be the subject of a later release.
Dr. Vic Wall, President of Colossus Minerals and qualified person under National Instrument 43-101, is responsible for this release and has verified the contents disclosed.
About Colossus:
Colossus is an exploration and development Company focused on mineral resource properties in Brazil. The Company is currently focusing its efforts on the high grade gold-platinum-palladium Serra Pelada project in Para State, Brazil. Between 1980 and 1986 Serra Pelada was host to the largest precious metals rush in Latin American history. Coverage by 60 Minutes of this famous mining rush can be viewed at the following link: www.sixtyminutes.ninemsn.com.au/article.aspx?id=299887. In addition, the Company has another drill-ready gold project, Natividade, in the State of Tocantins, Central Brazil.
Contacts: Colossus Minerals Inc. Elina Chow Public Relations Manager (416) 643-7655 (416) 643-3890 (FAX) Email: This email address is being protected from spambots. You need JavaScript enabled to view it. Website: www.colossusminerals.com
SOURCE: Colossus Minerals Inc.
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