Colossus Minerals Inc.
TSX : CSI

Colossus Minerals Inc.

November 03, 2009 13:29 ET

Colossus Minerals Commences Metallurgical Testing on Gold-Platinum-Palladium Mineralisation from the Central Mineralised Zone, Serra Pelada

TORONTO, ONTARIO--(Marketwire - Nov. 3, 2009) - Colossus Minerals Inc. ("Colossus")(TSX:CSI) is pleased to announce that metallurgical test work has been initiated on the Central Mineralised Zone ("CMZ") of the Serra Pelada Project, the Colossus-COOMIGASP joint venture located in Para State, Brazil.

HIGHLIGHTS

  • Two representative drill-core samples are undergoing initial metallurgical testing:
    SPD-020A: 22.70 metres @ 22.52 g/t gold, 8.98 g/t platinum and 15.75 g/t palladium,
    (52.79 kilogram sample mass) and
    SPD-033: 26.0 metres @ 21.32 g/t gold, 3.98 g/t platinum and 5.70 g/t palladium,
    (70.43 kilogram sample mass)
  • Material characterisation studies of similar gold-platinum-palladium mineralisation from the Central Mineralised Zone have shown that the sulphide–poor mineralisation contains gold & platinum group elements ("PGE's') mainly in the form of metals and metal alloys which may be amenable to hydro- gravity concentration;
  • Initial test-work by hrlTesting Ltd. (Brisbane), with assaying by Genalysis Ltd., is focusing on gravity concentration with options for flotation and hydrometallurgical follow-up on head samples and gravity tails.

DETAILS

The CMZ contains the bulk of high-grade gold/PGE mineralisation so far known from drilling at Serra Pelada and was also the focus of garimpeiro production from the historic open pit. Characterised by intense hydrothermal carbonaceous- and argillic alteration mainly of meta-siltstones, the CMZ contains both steeply and shallowly dipping gold-PGE subzones that exhibit varying gold/PGE and some ultra high gold and PGE grades See also Sections 00, 100NE and others plus a plan view of Serra Pelada drill traces at www.colossusminerals.com.

Colossus and external consultants have undertaken extensive materials characterisation studies (reflected light petrography, scanning electron microscopy, electron microprobe analysis, screen fire assays and hydro- separations) on representative CMZ core samples. Gold-PGE mineralisation is sulphide-poor and typically exhibits highly structured distributions, spatially associated with carbon and kaolin rich domains. The gold and PGE minerals are not nuggety, with the bulk of the gold in the 100micron grain-size range. Gold grains commonly contain minor alloyed palladium as well as inclusions of PGE rich minerals including selenides. Separate PGE rich minerals appear to be mainly metals and compositionally complex alloys commonly intergrown with iron and manganese oxides. In progressive screening and screen fire assaying PGE's report more strongly to fine fractions than gold, reflecting the finer grainsizes of the PGE-rich minerals. First pass liberation and hydro-separation studies suggested that CMZ mineralisation may be amenable to hydro-gravity concentration, particularly of gold. Other dense minerals encountered in hydro-separates included rare-earth rich phosphates plus iron and manganese oxides/hydrous oxides.

Two +50kg samples, typical of carbonaceous and argillicly altered siltstones in the CMZ, were selected for initial metallurgical test work. These samples are composites from continuous intervals of half drill core from SPD- 020A and SPD-033 remaining after assay and are representative of mineralised subzones respectively with relatively high PGE/gold and moderate PGE/gold. An ultra high grade interval in SPD-020A (from 231.1 metres downhole, 1.96metres @ 207.15g/t gold, 162.78 g/t platinum and 219.25g/t palladium) was excluded from the metallurgical sample in order to maintain a more representative bulk gold/PGE. Information on the sample composites is tabulated below:

Drill-hole
number
Assay interval
(metres, down-hole)*
Sample mass
(kilograms)
Gold
g/t
Platinum
g/t
Palladium
g/t
SPD-020A22.7052.7922.528.9815.75
SPD-03326.0070.4321.323.985.70

*Total assayed interval (>0.5 g/t gold equivalent) – excludes intervals of no core recovery.

The first stage of metallurgical testwork is assessing the amenability of Serra Pelada CMZ materials to gold and PGE recovery by gravity concentration. To this end, hrlTesting Ltd. (Brisbane) is utilising centrifugal gravity concentrators on a range of head sample grind sizes. Further gravity concentration tests and also flotation and hydrometallurgical options for recovery of gold and PGE's will be undertaken in light of results from the first round of metallurgical studies. Genalysis Ltd. (Perth) is assaying all metallurgical test samples and products.

TECHNICAL INFORMATION

Sampling of SPD core (by Colossus personnel) and sample preparation (by Intertek Limited, Parauapebas) were carried out under strict protocols recommended in the 43-101 Technical Report on Serra Pelada. After photographing and logging, intervals of HQ or PQ core (drilling advances, averaging 1 m in length) were cut and/or split in half, yielding samples of 2 to 5 kilogram mass. Intertek pulverised 1 or 2 kilogram splits (>95% passing 106 microns) from the crushed (>95% passing 1.7 mm), dried samples. A 200 gram aliquot was rotary split from each pulp by Intertek and these samples were securely shipped directly by Intertek to Genalysis Limited, Perth Laboratory. Duplicates, blanks and certified gold/PGE reference materials were inserted in the sample train by Colossus personnel prior to Intertek preparation work.

Genalysis inserted additional blanks, duplicates and high grade gold/PGE reference materials in the assay stream and replicate assays were performed routinely and on most medium to high grade materials. Fire assays for gold, platinum and palladium were on 25 gram subsamples utilising a lead rich collector material and ICP-MS finish. 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, replicates and also all reference materials were well within generally accepted QA/QC measures. Reference materials and also selected high value samples from all batches will later be check assayed independently.

On the basis of the assay results and core logging, contiguous intervals of remaining half core from SPD-020A and SPD-033 were selected and dispatched to hrlTesting Ltd. (Brisbane) for the metallurgical test work. Gold and PGE grades of the composited samples were estimated on a sample mass weighted basis and will be checked by assays of sample splits.

HrlTesting split each of the composited samples after crushing, retaining one split for a second stage of metallurgical testwork. The balance of each composite was stage crushed and split into 5 kilogram charges for a series of gravity concentration (initially utilising a Knelson concentrator) and screen sizing tests. Assaying of screened fractions, gravity concentrates and gravity tails will be undertaken by Genalysis Limited (Perth).

Dr. Vic Wall, Vice President of Exploration of Colossus Minerals and the qualified person under National Instrument 43-101, is responsible for this release and has verified the contents disclosed.

About Colossus:

Colossus is a minerals development company focused on a high-grade gold-platinum-palladium project in Brazil. The Company is currently focusing its efforts on the Serra Pelada project in Para State. 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: http://sixtyminutes.ninemsn.com.au/article.aspx?id=299887.

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