Montero Mining and Exploration Ltd

Montero Mining and Exploration Ltd

December 05, 2011 09:01 ET

Montero Provides an Update on the Mineral Processing and Hydrometallurgical Testwork on the Carbonatite from the Wigu Hill Rare Earth Project in Tanzania

TORONTO, ONTARIO--(Marketwire - Dec. 5, 2011) - Montero Mining and Exploration Ltd. (TSX VENTURE:MON) ("Montero") provides an update on the mineral processing and metallurgical testwork performed to date on the bastnaesite-rich carbonatite material from the Wigu Hill Rare Earth Project in Tanzania. In early 2010, Montero approached Mintek, an internationally recognized metallurgical research and testwork facility in Johannesburg, South Africa, to test the Wigu Hill carbonatite for recovery of Rare Earths. Mintek have over 25 years of Rare Earth experience working on research and testwork programs developing economic process routes for various Rare Earth materials.

Dr. Tony Harwood, President and Chief Executive Officer of Montero commented, "Montero initiated mineral processing and hydrometallurgical testwork on the mineralized material from Wigu Hill before drilling had started on the deposit. The exploration team realized that the challenge at Wigu Hill was not in the exploration, proving up the grade or tonnage, but in the metallurgical process routes that need to be defined to yield saleable rare earth products. Montero is well advanced in the metallurgical flowsheet established by our team with Mintek and this is on track with our First Producer Mine to Market strategy."

Montero's strategy to become the first Rare Earth Element ("REE") producer in Africa required embarking on a series of early preliminary metallurgical testwork and analysis on the mineralised carbonatite material from Wigu Hill. In early as 2010 the initial mapping of Wigu Hill demonstrated the potential for a significant mineralized system where the major challenge would be the mineral beneficiation, hydrometallurgy and production of saleable rare earths. A research program to identify, test and determine the critical path to rare earth production was the reason for starting the testwork at such an early stage in the exploration program. In 2010 Montero established a team led by Mike Evans that worked with Mintek on an extensive literature research program to identify: 1) a minerals processing route to produce a bastnaesite mineral concentrate and 2) a hydrometallurgical process route for the production of saleable rare earth products.

Montero delivered the first representative bulk sample, obtained from the Twiga and Tembo zones at Wigu Hill, to the Mintek facility in Johannesburg in June, 2010 followed by a second sample in July, 2011. These un-weathered and course grained bastnaesite rich samples were taken from trenches and pits in the Twiga and Tembo Zones where Montero has subsequently completed a NI 43-101 Inferred Resource Estimate (see news release dated 12/09/2011 -

1) Preliminary Minerals Processing Testwork to produce a bastnaesite mineral concentrate

The samples were initially sent for mineralogical analysis, crushed and assayed and then submitted for a program of mineral processing testwork which included; screening tests, gravity tests, magnetic susceptibility tests, X-ray sorting, and flotation tests. The target was to upgrade the run of mine mineralized carbonatite material to a rare earth mineral concentrate (essentially a bastnaesite mineral concentrate) which could potentially be sold as is to interested parties or become the feed stock to a hydrometallurgical refinery for the processing and sale of rare earth chemical grade products. This mineral processing testwork is still in progress.

2) Preliminary Hydrometallurgical Refinery Testwork to produce saleable Rare Earth chemicals

The detailed literature work enabled the team to develop a hydrometallurgical flowsheet with a two-stage Rare Earth Refinery recovery process;

  • Stage 1 Refining - The leaching of the bastnaesite mineral concentrate from the mining and mineral processing plant followed by a precipitation stage to produce a Mixed Rare Earth Oxide ("MREO") or chloride chemical saleable product, and;
  • Stage 2 Refining - The continued processing of the MREO concentrate solution and the extraction via Solvent Extraction (SX) and Ion Exchange ("IE") technology the individual REE's as metals or chemical compounds.

To view a conceptual illustration of the flowsheet currently being tested visit:

In early 2011, Mintek initiated a hydrometallurgical Refinery testwork program to develop a leaching and extraction process for the production of high purity rare earth elements as saleable chemical products. Details are outlined below.

Stage 1 Refinery Testwork

Leaching tests were performed using a variety of leaching agents and from this it was determined that a hydrochloric acid ("HCl") leach process was the most chemically efficient for the Wigu Hill bastnaesite-rich material. Following the success of the initial program a second and more recently, a third stage of leaching tests is currently being performed to provide further optimization information for the leaching process developed. The third stage optimization tests will provide a definitive process route for the leaching of the Wigu Hill mineralized carbonatite. Acid consuming gangue material is dissolved using hydrochloric acid in order to expose the bastnaesite-rich material. The residue is then leached with caustic soda to remove the silica and expose the rare earths minerals for subsequent dissolution in a further hydrochloric acid leach.

The results to date are encouraging and in addition to optimizing the main leaching processes, the program includes detailed mineralogy of the residues from the various stages. Testwork is also evaluating the potential for regenerating spent hydrochloric acid and caustic soda consumed in the process. The program includes working with a SysCAD mass balance program that is used to model the bulk leaches and the phases to produce a MREO saleable product. The final product of this process will also provide a feed solution for the Stage 2 Refining testwork.

Stage 2 Refinery Testwork

Montero and Mintek will embark on a testwork program that will commence in early 2012 to define the process route to take MREO feedstock and produce individual, pure rare earth chemicals or metals. Once completed, this testwork program will lead to a feasibility study for the Stage 2 Refinery and the upgrade of the Stage 1 Refinery to a larger production of REE chemicals and metals.

The Stage 1 hydrometallurgical Refinery optimization testwork will be completed by year end and presented by Mintek for evaluation by Montero. This will generate sufficient data to form the Design Basis for a feasibility study. The deliverables of this feasibility study will be a "Demonstration Plant" for a Leaching and Mixed Rare Earth Oxide ("MREO") Refinery facility targeting the production of 3,000-5,000 tpa of mixed rare earth chemical products for sale. The facility will also provide pregnant solution for solvent extraction testwork leading to the feasibility study of the Stage 2 Refinery that will target production of the individual rare earth chemicals or metals for sale.

Montero is currently assembling an expert metallurgical and hydrometallurgical team to undertake this work and has sent out enquiries to engineering companies to undertake the feasibility and eventual construction of the REE refinery.

Qualified Person's Statement

The technical information contained in this press release has been reviewed by Mr. Mike Evans, M.Sc. Pr.Sci.Nat., who is a qualified person for the purpose of National Instrument 43-101 and a consulting geologist to Montero.

About Mintek

Mintek, South Africa's national mineral research organization has over 25 years experience in REE extraction and is one of the world's leading technology organizations specializing in mineral processing, extractive metallurgy and related areas. Working closely with industry and R&D institutions and reporting to the South African government's Minister of Mineral Resources, Mintek offers a complete range of process development services, from preliminary bench-scale investigations to large-scale piloting and integrated flowsheet development in support of bankable feasibility studies. Engineering design, plant construction and commissioning are carried out in conjunction with international partners. Comprehensive laboratory and piloting facilities for sample preparation, milling, flotation, physical separation, smelting, leaching, pressure leaching, and metal recovery and purification are supported by internationally accredited analytical laboratory and mineralogical services. For further information on Mintek, please visit

About Montero Mining and Exploration

Montero Mining and Exploration Ltd. is a mineral exploration and development company engaged in the identification, acquisition, evaluation and exploration of mineral properties primarily focused on rare earth elements (REE), phosphates and uranium in Tanzania, South Africa and Quebec, Canada. Montero is focused on adding value for all shareholders through the acquisition and exploration on properties, which have the highest potential for future discoveries or development of existing mineral resources into mineable reserves. We remain engaged in the development of our flagship Wigu Hill Rare Earth Element Project in Tanzania, which is a high-grade, undeveloped Light Rare Earth Element deposit. The Company's current focus is on further exploration drilling to add to our initial NI 43-101 Mineral Resource Estimate. With the rising prices of REEs and China's control over export quotas, it is becoming imperative that the rest of the world develops new rare earth resources to meet the increasing demand from "green" technology and high-tech applications.

Montero's growth strategy is to develop the Wigu Hill Rare Earth Element project and to bring this to account through eventual rare earth production and cash flow, while operating in an environmentally and socially responsible manner. We will continue to add value through the development of our portfolio of properties. Montero has 54.7M shares outstanding and trades on the TSX Venture Exchange under the symbol MON.

Signed. Dr. Tony Harwood - President and CEO

This News Release includes certain "forward-looking statements". These statements are based on information currently available to the Company and the Company provides no assurance that actual results will meet management's expectations. Forward-looking statements include estimates and statements that describe the Company's future plans, objectives or goals, including words to the effect that the Company or management expects a stated condition or result to occur. Forward-looking statements may be identified by such terms as "believes", "anticipates", "expects", "estimates", "may", "could", "would", "will", or "plan". Since forward-looking statements are based on assumptions and address future events and conditions, by their very nature they involve inherent risks and uncertainties. Actual results relating to, among other things, results of exploration, project development, reclamation and capital costs of the Company's mineral properties, and the Company's financial condition and prospects, could differ materially from those currently anticipated in such statements for many reasons such as: changes in general economic conditions and conditions in the financial markets; changes in demand and prices for minerals; litigation, legislative, environmental and other judicial, regulatory, political and competitive developments; technological and operational difficulties encountered in connection with the activities of the Company; and other matters discussed in this news release. This list is not exhaustive of the factors that may affect any of the Company's forward-looking statements. These and other factors should be considered carefully and readers should not place undue reliance on the Company's forward-looking statements. The Company does not undertake to update any forward-looking statement that may be made from time to time by the Company or on its behalf, except in accordance with applicable securities laws.

CAUTIONARY STATEMENT: Neither TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in the policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this release.

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