Avalon Provides Progress Report on Metallurgical Testwork, Nechalacho Rare Earth Elements Deposit, Thor Lake, Northwest Territories, Canada
Toronto, Ontario – April 5, 2011 – Avalon Rare Metals Inc. (TSX:AVL)(NYSE Amex:AVL) (“Avalon” or the “Company”) is pleased to provide an update its progress on the Nechalacho deposit, Northwest Territories, Canada.
Avalon is continuing to conduct metallurgical testwork toward proving its proposed process for concentration of the Nechalacho ore minerals. This process is designed to produce rare earths, niobium (Nb), tantalum (Ta), and zirconium (Zr) products from those minerals.The process begins with froth flotation in a Flotation Plant to concentrate the ore minerals. This is followed by a leaching process to chemically break down the ore minerals in a Hydrometallurgical Plant which brings the rare earths and by-product rare metals into solution. The final stage will be rare earth separation in a Separation Plant to produce refined individual rare earth oxides.
Overall, the various metallurgical test programs to prove these processes are progressing steadily and close to original projected timelines, except that the hydrometallurgical pilot plant work is now forecast to take up to four months longer to complete than originally estimated, in order to achieve the highest level of confidence in the process design. The forecast completion date for the Bankable Feasibility Study (BFS) in mid 2012 could be delayed until the fourth quarter of 2012 if the time estimate to complete the hydrometallurgical pilot plant is accurate. Commented President Don Bubar, “We have been pleased with the progress achieved to date on our metallurgical test program and are now implementing measures to ensure that the hydrometallurgical pilot plant work does not significantly delay the completion of the bankable feasibility study.”
The additional time and complexity of the hydrometallurgical pilot plant work, in addition to more updated cost information for other areas of the BFS, have resulted in an increase in the BFS budget to $54 million, which is comprised of direct costs of $46 million and administrative and overhead costs of $8 million. This compares to the previous budget of $47 million, which was comprised of $40 million in direct costs and $7 million in administrative and overhead costs. Approximately $11 million of the BFS budget has been spent to date.
Understanding the mineralogy is an important step to both developing and improving metallurgical processes. To this end, Avalon has carried out multiple mineralogical studies at SGS Minerals Services, Lakefield, ON (“SGS”), Xstrata Process Support, Sudbury, ON (“XPS”) and McGill University, Montreal, QC. The results to date have indicated that the light rare earths (LREE) in the Nechalacho deposit are contained in four minerals: allanite, monazite, bastnaesite and synchisite, and the heavy rare earths (HREE) are present in two minerals: fergusonite and zircon, the latter also being host to zirconium (Zr). niobium (Nb) and tantalum (Ta) are present in fergusonite and columbite1. Mineralogical studies continue in all three research centres.
Extensive flotation tests, including many locked cycle tests, have been undertaken since 2008 at SGS and the basics of the process for concentration of the valuable minerals have been defined. The tests have utilized a number of representative composite samples of both the Basal and Upper Zones and from various geographic areas within the Nechalacho deposit.
The flotation process comprises crushing and grinding to a grain size of less than 38 µm (microns), leading to de-sliming to remove particles less than 8 µm, then the removal of barren magnetite through magnetic separation. The feed then passes through Rougher and Cleaner flotation stages, followed by gravity concentration, where the valuable minerals are separated from waste minerals.
This process has been refined through bench-scale testing, including locked cycle tests at SGS. Tests have been repeated and confirmed at XPS.
Subsequent to the completion of the bench-scale testing, Avalon commissioned XPS to conduct two mini-pilot plant (“MPP”) tests. The MPP facility allows testing of flotation schemes at sample rates of about 8 kg/hour or, for a five day campaign, about one tonne, thus simulating an industrial scale plant. The utilization of a sample of about 1 tonne in weight means sufficient sample material can be readily obtained from diamond drill core sample material. Two such composite samples from Basal Zone have been tested to date.
The MPP runs comprised initial crushing of the sample at XPS in Sudbury with the next step being carried out at Process Research Ortech in Mississauga, Ontario, where the sample was ground to less than 38 µm, de-slimed and the magnetic fraction removed. The prepared sample was then trucked to Sudbury on a daily basis for the remaining flotation processing. The MPP was a continuous operation from flotation feed conditioning through to concentrate with the prepared feed delivered in time to maintain continuous operation.
The MPP demonstrated that recovery targets outlined previously by Avalon should be achievable. In addition the results of the MPP tests provide important information for further enhancement of the flotation scheme. As a result, further bench-scale testing is underway at both XPS and SGS focused on specific aspects of the flotation process. Some of the tests will examine changes in reagent schemes. In addition, a pilot-scale multi-gravity separator that promises enhanced gravity separation of finely ground feed is being evaluated for use in future MPP tests and the larger scale flotation pilot plant.
The MPP testwork is an interim step designed to identify key design criteria for the larger scale flotation pilot plant trial and economize on the cost and the size of the bulk sample required for the large scale trial. Additional MPP testwork is planned for completion by the end of the June, 2011.
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