Pancontinental Uranium Corporation (TSX VENTURE:PUC) has reported that its joint venture partner, Crossland Uranium Mines Ltd, (ASX:CUX) has identified extensive alluvial deposits that host heavy minerals containing rare earth elements at the joint venture's Charley Creek Project area in Northern Territory, Australia.
These REE deposits are separate from Crossland's uranium prospects, which remain the Joint Venture's primary focus at Charley Creek and elsewhere.
- A heavy mineral concentrate produced by Crossland from a sample of stream channel alluvium has returned high values for REE, (39% total rare earth oxide), with particularly high proportions of the heavy REE, including Gadolinium (Gd), Terbium (Tb), and Dysprosium (Dy). These are present in phosphate minerals that should be readily processed using available REE extraction technology.
- Crossland believes that these REE ratios are typical of those throughout the Cockroach Dam Prospect, within the Charley Creek Project, and that they will extend over a broader area both in bedrock and alluvium derived from these bedrocks. A substantial tonnage potential for REE-bearing alluvium in various settings is evident from exploration techniques already developed and applied in the area.
- The target types are found on surface and near-surface, and are loosely consolidated deposits that should be amenable to relatively low cost exploration and mining methods.
- An initial development objective for stand-alone development would be production of a saleable REE-rich heavy mineral concentrate at a rate of several thousand tonnes per annum. The permitting and capital costs of such an operation should be relatively low.
During follow-up of Crossland's detailed ground spectrometer surveys of the Cockroach Dam uranium prospect (NT) in the Teapot Granite during 2009, geologists identified rock samples returning elevated levels of rare earth elements (REE). These rocks outcropped in areas with their own characteristic radiometric pattern, generally unrelated to the uranium anomalies, which remain the Crossland/Pancon Joint Venture's primary focus in the Charley Creek Project.
Subsequent follow-up of areas with similar radiometric patterns established that there were widespread areas with elevated rare earth values. Sampling of rock outcrops revealed that the REE suite contained unusually high proportions of the heavy rare earth elements, particularly Dysprosium and Terbium, which are reported to be in short supply globally. Furthermore, there were extensive eluvial and alluvial sediments developed from direct weathering of these REE-enriched rocks, and these in places appeared to have significantly upgraded content of the heavy minerals that contain the REE. Therefore, it appears there is potential to examine development of a relatively low capital cost route to production of a marketable REE heavy mineral concentrate from near-surface deposits.
Crossland has sought expert guidance on the likelihood that this type of occurrence had commercial possibilities, and the expert confirmed the possibility for a development target based around alluvial deposits of heavy minerals enriched in heavy REE. He recommended that the first step in the evaluation of the prospects was to investigate if heavy mineral concentrates could be produced using simple physical separation methods based around the specific gravity of the REE bearing minerals. Several kilograms of pan concentrate was produced in the field and submitted to the laboratory for heavy liquid separation, as the first step in this appraisal.
While this sample relates to stream sediment collected from one drainage, Crossland's reconnaissance rock sample results leads us to expect that the REE mix reflected here should be typical of those from other drainages so far sampled in the Cockroach Dam Prospect.
The initial analysis of this material has now been received. In reporting these results, Crossland cautions that analyses have been performed by the accredited laboratory, ALS Global, using their method ME-MS81h, a lithium borate fusion/nitric acid digest method specifically developed for analysis of high contents of REE. However, the analyses exceed the upper level of detection for six of the REE: Ce, Gd, La, Nd, Pr, and Sm, so for these elements the analyses need to be repeated by an even less sensitive method to obtain absolute values. Electron microprobe work undertaken by Crossland has confirmed that the REE bearing phase is a phosphate mineral, which should result in good recoveries with currently standard REE extraction technology.
Initial comparisons with other published information on REE distribution in potential and operating deposits suggests that the Cockroach Dam distributions are particularly elevated in Gadolinium, Terbium, and Dysprosium, and additionally the rarer heavy REE, such as Holmium, Erbium, Thulium, Ytterbium, Lutetium, and Hafnium, which together total almost 1% of the Rare Earth Oxide (REO) mix.
Crossland believes that these results are sufficient to justify implementation of a supplementary exploration program to appraise the extensive areas of alluvium that exhibit the characteristic radiometric response that has led us to these results in the Cockroach Dam Prospect area. This work would be separate from uranium exploration efforts, which are on nearby, but separate areas. Because of the shallow and widespread nature of the potential alluvial REE resource, it will be possible to evaluate the REE potential quickly and relatively cheaply.
There are four distinct alluvial settings within Crossland and Pancon's Charley Creek Project areas that may host viable REE heavy mineral occurrences.
- Active streams draining immediately from areas of bedrock containing elevated values of REE
- Residual fossil drainage systems and eluvial deposits in areas of shallow REE- enriched bedrock
- Broad alluvial flats associated with the more prominent streams in the Cockroach Dam/Teapot drainages
- Large alluvial outwash fans that are sourced in the Cockroach Dam/Teapot Granite Hills, and spread across the alluvial flats to the north of the MacDonnell Ranges.
These sources probably have decreasing alluvial grade potential, but increasing tonnage potential, in the order listed. Crossland and Pancon would initially target an alluvial resource capable of relatively rapid and low-cost exploration, permitting, and development, to produce several thousand tonnes of heavy mineral concentrate per annum in a stand-alone operation. If Crossland and Pancon succeed in establishing a viable uranium resource on adjacent uranium anomalies currently being drilled, then the possibilities for an on-site processing plant would be enhanced.
Crossland intends to propose to develop the REE sampling program as a program to engage local Aboriginal youths in working with us in the exploration industry.
All technical information in this release has been reviewed by Geoff Eupene, Qualified Person for Crossland and Pancon.
Source: Pancontinental Uranium Corporation