Tirari Desert (part of the Gypsum Cliffs Project). Combined first annual/final report to licence expiry/full surrender, for the period 21/6/2013 to 20/6/2014.
Created: 12 Nov 2024 Revised: 12 Nov 2024

EL 5277 is located in the Lake Eyre region approximately 110 km north of the settlement of Marree. The licence is one of five original applications that were made by Crossland Strategic Metals Limited (formerly Crossland Uranium Mines Limited) on...

EL 5277 is located in the Lake Eyre region approximately 110 km north of the settlement of Marree. The licence is one of five original applications that were made by Crossland Strategic Metals Limited (formerly Crossland Uranium Mines Limited) on 14/5/2012 to explore the region for Quaternary and Recent alluvial-regolith hosted REE mineralisation. Crossland’s attention was drawn to the region following the release of a report by Geoscience Australia (GA) of a detailed, nation-wide sampling survey project conducted between 2007 and 2009. The report, titled ‘The National Geochemical Survey of Australia’ (NGSA, Caritat P. 2011), was a collaborative effort between GA and State and Territory geoscience agencies. Crossland, which is in the process of investigating a large, alluvial-hosted REE resource near Alice Springs, noted that results of the GA sampling within the massive drainage complexes of the Lake Eyre region exhibited certain encouraging rare earth elemental values. These results fell within the maximum grouping for those element populations over the national survey area. A field visit was made to the subject tenement in July 2012 by Crossland technical staff to assess the various drainage lines by collecting bulk stream sediment samples. Once processed and analysed, the sampling results would enable the company to make an informed decision on land retention. A single site for sampling was selected on the overbank floodplain of the Cooper Creek drainage system, from which Crossland collected six samples. The site chosen was located within about 10 m approximately to where the NGSA personnel had acquired their sample which gave the high REE values. To replicate the NGSA procedures, the samples were taken from pits dug to a depth of 60 to 80 cm, with approximately 100 kg taken from the site. Following sample collection the excavations were back-filled. At the time of the visit, additional sites were not accessible, either due to flooding or landholder concerns. Upon completion of the field work, the samples were taken to Crossland’s heavy mineral sands processing facility near Alice Springs. A “head grade” sample was sent for assay, before 25 kg of sediment from each sample were processed. Sample processing steps included sieving, desliming, Wilfley tabling, attritioning and magnetic separation. A flowsheet diagram illustrating the full procedure is included in the subject report. Each sampling product was then sent for assay. Initial REE results from the head grade assays were found to be much lower than the corresponding NGSA results. This was attributed to a grain size factor, as Crossland had sent the whole sediment sample subset to be assayed rather than the 0-75 microns fraction. The assay results returned from five 20 kg processed sample subsets proved to be much more promising. Titanium minerals, zircon, rare earth bearing minerals, and other valuable trace metals (Ag, Cr, Hf, Nb, Sn, Ta, Th, U, and W) were found to be easily concentrated using simple mechanical processes. Assay values returned from the rare earth bearing mineral concentrate represented up to 59 times the average continental crust abundance for individual REE. It was noted that some of the HREE are more concentrated than the LREE, and the HREE/total REE ratio was over 50% in some of the sample concentrates. Zirconium and hafnium were by far the most abundant HREE within these. It was anticipated that drainage areas of higher initial heavy mineral grain content could be readily located with further exploration. Given the valuable composition of the initial samples' concentrate, a high enough bulk sediment content of heavy minerals should translate into an economically profitable product. It was expected that the heavy mineral fraction of the sediments would be readily recoverable using conventional technologies, in the same manner that REE bearing heavy minerals are recoverable using the mineral sands technology employed by Crossland at Charley Creek. The presence of zircon and probably rutile would dominate the value of the HM samples obtained; these two minerals alone appeared to make up over 50% by mass of the non-magnetic concentrate mix. Following further evaluation of the data obtained from the six samples (nos 204401 - 204406), and given the prevailing difficult economic conditions that pervade the junior exploration industry, it was decided to fully surrender tenure.

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Use constraints License
License Creative Commons Attribution 4.0
Persistent identifier https://pid.sarig.sa.gov.au/document/mesac25391
Citation Melville, P. Tirari Desert (part of the Gypsum Cliffs Project). Combined first annual/final report to licence expiry/full surrender, for the period 21/6/2013 to 20/6/2014. Mineral Company Report - Mineral Exploration
https://pid.sarig.sa.gov.au/document/mesac25391

Technical information

Status
Maintenance and Update Frequency
Geographic Reference GDA2020 (EPSG:7844)
Geo bounding box {"type":"Polygon","coordinates":[[[137.5,-29],[138.5,-29],[138.5,-28.5],[137.5,-28.5],[137.5,-29]]]}
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