Giant Placer Project

Summary
Pegasus’ 100% owned Giant Placer Project tenements cover the unconsolidated section of an auriferous giant placer generated by the ancestral Sturt palaeodrainage following deep chemical weathering and Tertiary lateritisation of the auriferous Halls Creek Group.

The placer is world class in dimension and dwarfs all previous placer discoveries in Australia. It is analogous in provenance area to the Klondike Schists of the Yukon and in structure to the Californian dredging fields of Hammonton, Folsom and Oroville. The placers of the Klondike and California have each produced over 12 million ounces of gold.

The presence of gold in part of the placer has been confirmed from regional sampling by a diamond explorer during the 1980’s.

The placer provides the opportunity to define a very large gold and heavy mineral resource within a newly discovered well recognised geological host with proven resource-bearing potential.

Introduction
The Giant Placer Project is centred some 75 kilometres southeast of Halls Creek in the East Kimberley Division of Western Australia. It consists of four granted exploration licences E80/3616 – E80/3619 covering an area of some 924km².

Geological Setting
The tenements encompass a thick blanket of auriferous gravels laid down by fluvial processes during the Tertiary over flat lying Upper Proterozoic basinal sandstones (Flat Rock Formation) flanking the Halls Creek Mobile Zone.

The Halls Creek Group consists primarily of regionally metamorphosed geosynclinal sediments and volcanics supporting a prodigious number of weakly auriferous quartz veins.

These are postulated as the source of mineralisation in the placer.

Satellite Image showing Tertiary Drainage from Mineralised Occurrences
(Click to enlarge)

The gravels are concealed by a veneer of black soil supporting a virtually treeless Mitchell Grass covered section of the Canning Plains.

The gravel blanket contains a high component of vein quartz cobbles believed to have been generated by deep chemical weathering of the Lower Proterozoic Halls Creek Group, a major component of the eastern section of the Halls Creek Mobile Zone.

In the centre of the unconsolidated placer within the Giant Placer Project area, at a locality named Rocket Tank on the Cow creek 1:100,000 Sheet a large soak has been excavated for stock watering.

Above: Google Image showing Rocket Tank Location & Below: Excavated Soak
(Click to enlarge)

The Excavation has exposed the top of an unconsolidated gravel “blanket” in which the clasts are composed almost entirely of blue/grey vein quartz derived from the auriferous Hall Creek Group.

Placer Generation
The placer was generated from the ancestral Elvire palaeodrainage following Tertiary lateritisation of the regionally extensive auriferous Halls Creek Group. Prior to recent river capture by a rejuvenated lower Ord, the Elvire was a tributary of the Sturt drainage system.

In common with other giant placers throughout the world, secular deep chemical weathering of the auriferous Halls Creek Group during the Tertiary transformed substantial depths of rock into laterite profiles and clays
.
Cyclical denudations stripped the laterites and transported the easily suspended clays over substantial distances to form the Lake Gregory Beds.

Non reactive heavy components (gold and auriferous quartz veins) were dumped on the adjoining (Canning) plains (when gradients and stream velocities diminished), to be further concentrated by fluvial processes (braided streams) into auriferous giant placers of the ‘gravel plain’ category.

Structurally the Halls Creek Giant Placer it is in part an analogue of the gravel plain placers of the Californian dredging fields of Hammonton, Folsom and Oroville. These placers are around 100 kilometres from the gold source. Each field has produced around 4 million ounces of gold.

From a provenance perspective, auriferous mineralisation within the placer source area, (the Halls Creek Group of metamorphic rocks), offers a close parallel to the Klondike Schists of the Yukon, scene of one of the world’s greatest alluvial gold rushes.

Whilst deep chemical weathering of regionally extensive though weakly auriferous Klondike Schists during the Tertiary provided miners with over 12 million ounces of alluvial gold in placer gravels, the source rocks have yet to support a mine of significance on primary ore.

Previous Mining and Exploration
The area within the tenement boundary has never been the subject of a tenement application by another party.

Regional soil sample traverses undertaken by a diamond explorer over a sand covered lateritised southern extension of the placer, generated a regional gold anomaly ranging from 15 – 42 ppb Au over a large area.

Following resampling, the anomaly was dismissed as ‘palaeodrainage contamination’ and no follow-up work was done.

Giant Placer Project - Gold Potential
The project conforms with all the principal requirements for major placer resource since:

1. Provenance requirements are satisfied with the upper Elvire drainage basin being primarily confined to the auriferous Halls Creek Group.
2. Interpreted uplift of the Halls Creek Group block created a high energy environment.
   
3. Climatic conditions during the Tertiary were highly favourable with deep chemical weathering enabling land surface erosion of considerable depth over the Halls Creek Group.
   
4. The base on which the Canning Plains gravels are deposited is gently dipping (Flat Rock Formation) with strata of varying resistance to erosion generating large trap sites for gold accumulation.
   
5. The Elvire palaeo-drainage system is undiluted by non-contributing tributaries resulting in a high auriferous quartz vein component in the gravel ‘blanket’.
   
6. Gold content of alluvium in former dredging claims in the upper reaches of the Elvire reported by Finucane (1939) at 3 grams per cubic metre is high.
   
7. The palaeo-drainage system was long standing allowing considerable reworking.
   
8. Geochemical sampling conducted over a part of the placer has defined an extensive gold anomaly ranging from 15 – 42 ppb Au.

On the basis of the above criteria and the size of the gravel blanket, the deposit holds the potential for the definition of a very large gold resource.