Provides An Exploration and Metallurgy Report for February 2012
Stromberg Heavy Rare (HREE) Prospect - HREE in Clay
- New metallurgical test results have identified that part of the heavy rare earth content at Stromberg is associated with clay material.
Geological similarities to other rare earth (REE) clay deposits have been noted. Clay deposits can be major low cost producers of rare earths. Metallurgical work is ongoing to assess mineral processing flow sheet options.
- The geological processes leading to the formation of such clay deposits tend to be widespread and this significantly increases the district exploration potential for this style of HREE mineralisation around Stromberg.
- Other test results have continued to identify the presence of Xenotime (highly sought after and easily processed heavy rare earth mineral) in all samples.
REE Industry Strategic Partner Strategy
- TUC's Stromberg Prospect continues to attract industry attention due to its HREE metal mix (85% HREE), potentially simple flow sheet options and exploration upside. We are in discussions with various industry players in relation to a possible strategic partnership. Our strong desire is for a cornerstone investor that can support us financially, technically and in product marketing.
Land Access - Tenements surrounding Stromberg
- A planning meeting has been held with the Northern Land Council with respect to Traditional Aboriginal Landowner engagement in HREE prospective tenements surrounding Stromberg. A strategy for engagement was laid out for the 2012 and 2013 calendar years.
Successful land access negotiations could provide access to a number of additional HREE exploration targets in the district.
Drill Planning - Stromberg HREEs
- Planning work is underway for metallurgical and resource definition drilling at the Stromberg HREE Prospect. Progress has been made this month with the scheduling of a detailed airborne laser based topographic survey. This is considered an essential component of a successful drilling program in 2012.
Quantum Rare Earth Prospect Update
- Geological modelling work has progressed at Quantum. Modelling is showing potential for a large amount of REE material and highlighting additional exploration targets. TUC are awaiting a final metallurgical report and will consider this information in conjunction with an assessment of exploration up-side. Further work will be considered on completion of this review.
Stromberg Heavy Rare Earth Prospect
Daly Project, EL25222
Recent Metallurgical and Mineralogical Test Results
Recent metallurgical work on samples representative of the whole of the Stromberg Prospect at a variety of grades has included the screening of four bulk samples at fractions between 45µm and 2mm. Screening was followed by heavy liquid separation by centrifuge of the finer fractions to review mineralogy.
Analysis of the screened fractions indicates that significant levels of HREE are associated with kaolin (very fine clay mineral) and goethite (iron hydroxide). More than 70% of the rare earths are associated with the less than 45µm fraction (most likely clay material).
Mineralogical analysis has identified some xenotime (HREE or yttrium phosphate) in all samples and size fractions examined (to see Photos 1 and 2 and all other figures, please refer to the link at the bottom of release).
Metallurgical test work is ongoing to assess whether the Stromberg mineralised material is amenable to a simple chemical leach process either as a step or entire treatment towards a concentrate product. In conjunction with this leach test work, nanometre scale scanning electronic microscopy is also being undertaken to visually determine the nature of the HREE mineralisation associated with the clays.
The above work, coupled with geological understanding is showing mineralogical and physical similarities to some clay REE deposits. Clay REE deposits are known to be major low cost producers of rare earths. They are also known for their simple leach or ion exchange processing options which can extract up to 90% of the rare earths and produce higher grade concentrates.
Evolution of Geological and Metallurgical Model
The geological processes leading to the formation of clay REE deposits tend to be due to widespread chemical weathering of rare earth source rocks. This process, illustrated in Figure 2, is highly evident in geological logging at Stromberg.
At a broader scale, TUC have interpreted a number of repetitions of host rocks with substantial strike length across the Stromberg area. As the entire area has been subjected to the process of chemical weathering this interpretation makes the size of any HREE clay or other potential very serious. Figure 3 shows this district potential.
Stromberg 3D Interpretation and Other Activity
Geological modelling of the Stromberg Prospect is currently underway. The work is being used to plan the next rounds of drilling which are likely to include RC and diamond drilling for metallurgical, resource and geotechnical purposes.
To better design drill programs, and for mapping, planning and calculation purposes a highly accurate light detection and ranging (LiDAR) survey is being planned for Stromberg and it's surroundings.
TUC plans to drill the Stromberg Prospect towards resource in 2012.
Quantum Rare Earth Prospect
Pine Creek Project, EL25229
Ongoing 3D Interpretation and Other Activity
Geological modelling continues on the Quantum Prospect (Figure 4). Work is providing a 3D geological model of mineralisation to aid in an initial assessment of size and grade potential and to help guide exploration targeting work.
TUC are awaiting a final metallurgical report and will consider this information in conjunction with an assessment of exploration potential. Further work will be considered on completion of this review.
*Total Rare Earth Oxides (TREO's) have been calculated by addition of common oxide values for Ce, Dy, Er, Eu, Gd, Ho, La, Lu, Nd, Pr, Sm, Tb, Tm, Yb, Y. Rare Earth Oxide (REO) values have been calculated from Rare Earth Element (REE) ppm grades after analysis by lithium-metaborate fusion and ICPMS , where possible, or by HF/multi acid digest and ICPMS. The total REO is calculated as the sum of all REE as REE2O3, with the exception of Ce, Pr and Tb; which are calculated as CeO2, Pr6O11, and Tb4O7 respectively, in accordance with geochemical conventions.
Heavy Rare Earth Elements HREE = Dy, Er, Ho, Lu, Tb, Tm, Yb, Y;
Medium Rare Earth Elements MREE = Eu, Gd, Sm;
Light Rare Earths LREE Ce, La, Pr, Nd;
Total Rare Earth Elements - TREE.
To view the complete TUC Resources announcement including photos and figures, please refer to the following link below:
About Spectrum Rare Earths Limited
Spectrum Rare Earths Limited's (ASX:SPX) vision is to become a significant high margin mineral producer and resource house. The core purpose of Spectrum is to create value through the discovery, development, production and marketing of metal resources in a socially responsible manner.
Spectrum Rare Earths Limited