Plateau Energy Metals reports 75-79% Lithium extraction to sulphate solution regardless of grain size fractions from Falchani High-Grade Lithium Mineralization – New test work to start at ANSTO

TORONTO, April 19, 2018 (GLOBE NEWSWIRE) -- Plateau Energy Metals Inc. (“Plateau” “PLU” or the "Company")(TSX VENTURE:PLU)(FRANKFURT:QG1)(OTCQB:PLUUF), a lithium and uranium development company, is pleased to announce continued metallurgical test results from the Falchani discovery at its Macusani Plateau lithium/uranium project in Peru. The grain size versus leaching test work was completed by TECMMINE, a Peruvian metallurgical consulting company based in Lima, Peru, and was reviewed by Grenvil Dunn of Hydromet (Pty) Ltd. ("Hydromet"). The test work forms part of the Company's continuing efforts to unlock value from the Falchani high-grade lithium discovery.

The Company also announces that a Falchani lithium mineralization bulk sample has been received by ANSTO Laboratories in Australia. ANSTO will be starting new test work including: lithium leaching, lithium product precipitation, product characterization and initial flowsheet design. This work should be completed within the next 4-8 weeks.

Highlights
The leach test work was conducted on samples of the Li-rich tuff drilled by the Company at the Falchani discovery. The 7.4 kg sample was crushed and milled to -2 mm and separated into 6 separate grain size fractions.

• Regardless of size fraction, leach results indicate that 75-79% of contained lithium was extracted from Falchani mineralization in open circuit sulphuric acid leach tests at 88°C conducted during 12-hour leach tests.
• Results confirm and support that lithium can be extracted from Falchani Li-rich tuff unit using a simple whole-of-ore leach process.
• Overall sample contained 3,846 ppm Li with separate size fractions ranging from 3,543 to 4,286 ppm Li showing consistent Li contents regardless of size fraction.
• Acid consumption is low, ranging from 162-192 kg Acid/t of feed, and is lower for coarser grind fractions.
• A Falchani bulk sample has been received by ANSTO where Li leach and product precipitation work has started with initial sample processing.

Ted O’Connor, CEO of Plateau Energy Metals commented: “This recent lithium leaching versus grain size fraction work continues to support using simple, warm sulphuric acid leaching under atmospheric pressure conditions and confirms ~80% Li extraction is achievable with relatively coarse milling requirements. Regardless of the individual size fractions studied, lithium leaching and lithium grades are remarkably consistent, with low acid consumption. This will have a clearly positive impact on potential operating costs from grade control, mining, milling and leach processing perspectives.

The large footprint of the Li-rich tuffs continues to be confirmed from mapping/sampling work and the on-going resource drill program at Falchani. We are continuing to gain confidence that Falchani will grow from a unique, new lithium discovery into a significant, high-grade lithium project, and its unique attributes will contribute to the future, positive economic potential of the Macusani project.”

Details
The Li-rich Falchani tuff was discovered in November 2017 and metallurgical test work studies commenced immediately in order to understand whether a low intensity atmospheric pressure sulphuric acid leach was effective in extracting lithium as well as other rare metals from this unique Li-rich mineralization. The high-grade sequence of Falchani tuff has drill indicated thicknesses up to 140 m with consistent lithium contents of 3,250 to 4,300ppm Li (0.70-0.92% Li₂O), and remains open in all directions. Outcrop mapping and sampling has expanded the footprint target of the high-grade Li-rich tuff unit to over 2 km², and drilling continues with 3 company-owned diamond drill rigs with the goal of establishing a large lithium (and uranium) resource at Falchani in Q2 2018.

The 7.4 kg Falchani Li-rich sample utilized for this test work contained 3,846 ppm Li and was crushed and milled to 100% passing -2 mm and screened into 6 separate grain size fractions as follows: -2mm to +1mm, -1mm to -500μm, -500μm to +212μm, -212μm to +75μm, -75μ to +38μ, and -38μm.

Identical open circuit acid leach tests were conducted on all grain size fractions with individual size fractions separately leached with an aqueous 20+% sulphuric acid lixiviant over 12 hours in stirred tanks at a temperature of 88°C. Kinetic samples were taken every 3 hours over the 12-hour leaching period.

The results of the lithium leach tests were, as follows:

• -2mm to +1mm fraction – representing 14.6% of total sample mass, contained 3,685 ppm Li and achieved 75.2% Li extraction after 12 hours with an acid consumption of 162 kg/t
• -1mm to -500μm fraction – representing 16.6% of total sample mass contained 3,772 ppm Li and achieved 77.5% Li extraction after 12 hours with an acid consumption of 165 kg/t
• -500μm to +212μm fraction – representing 16.2% of total sample mass contained 4,032 ppm Li and achieved 78.8% Li extraction after 12 hours with an acid consumption of 167 kg/t
• -212μm to +75μm fraction – representing 14.7% of total sample mass contained 4,286 ppm Li and achieved 79.1% Li extraction after 12 hours with an acid consumption of 176 kg/t
• -75μ to +38μm fraction – representing 7.6% of total sample mass contained 4,275 ppm Li and achieved 79.0% Li extraction after 12 hours with an acid consumption of 188 kg/t
• -38μm fraction – representing 30.3% of total sample mass contained 3,543 ppm Li achieved 75.0% Li extraction after 12 hours with an acid consumption of 192 kg/t.

This test work reveals several important and unique aspects of the Falchani high-grade Li-rich tuff.

1. Consistent Grade Distribution: All size fractions have similar Li contents with no one size fraction concentrating Li to any appreciable degree. No pre-concentration increase in Li grades will be possible.
2. Consistent Leaching Regardless of Size Fraction: All size fractions leach comparably with Li extractions ranging from 75.0-79.1% with no preferential size fraction leaching better than others. Optimal lithium leaching versus acid consumption appears to favour coarser grind sizes in the 75 to 500μm range.
3. Confirms Initial Leach Whole Rock Test Work: These leach test results confirm the initial Li extraction of the bulk Falchani tuff reported previously as 79.9% under identical conditions (refer to news release of December 11, 2017).

The consistently high lithium extraction to the aqueous phase regardless of grain size is extremely encouraging and additional leach and precipitation test work on the Falchani tuff high-grade lithium mineralization is scheduled to commence at ANSTO in Australia. Similar tests will continue in Peru. However, the current results continue to confirm that a relatively simple leach process flow-sheet is all that may be needed to extract lithium from the geologically unique, Li-rich tuffs at Falchani.

Qualified Persons
Mr. Grenvill Dunn, Pr Eng (RSA), C Eng (UK), FIChE, MSAIMM, MSAIChE of Hydromet Pty Ltd, a technical consultant to the Company, is a Qualified Person as defined under National Instrument 43-101 Standards of Disclosure for Mineral Projects, and has reviewed and approved the scientific and technical information contained in this release.

About Hydromet Pty Ltd
Hydromet Pty Limited is an international consulting company for the metals and mining industry. The company is based in South Africa and was established in 2000 by its director Grenvil Dunn. Mr Dunn is a Chemical Engineer with over 45 years of experience, particularly in mineral processing, flow sheet design and development with direct experience in uranium and lithium.

About Plateau Energy Metals
Plateau Energy Metals Inc. is a Canadian lithium and uranium exploration and development company focused on its properties on the Macusani Plateau in southeastern Peru. The Company controls all reported uranium resources known in Peru, significant and growing lithium resources and mineral concessions covering over 91,000 hectares (910 km²) situated near significant infrastructure. Plateau Energy Metals is listed on the TSX Venture Exchange under the symbol 'PLU', quoted on the OTCQB under the symbol “PLUUF” and the Frankfurt Exchange under the symbol 'QG1'. The Company has 65,088,457 shares issued and outstanding.

Forward Looking Information
This news release includes certain forward-looking statements concerning possible expected results of exploration and future exploration activities. Forward-looking statements are frequently identified by such words as "may", "will", "plan", "expect", "anticipate", "estimate", "intend" and similar words referring to future events and results. Forward-looking statements are based on the current opinions and expectations of management. All forward-looking information is inherently uncertain and subject to a variety of assumptions, risks and uncertainties, including risks and uncertainties relating to the interpretation of drill results, the geology, grade and continuity of mineral deposits; the possibility that any future exploration, development or mining results will not be consistent with our expectations; mining and development risks, including risks related to accidents, equipment breakdowns, labour disputes (including work stoppages and strikes) or other unanticipated difficulties with or interruptions in exploration and development; the potential for delays in exploration or development activities; risks related to commodity price and foreign exchange rate fluctuations; risks related to foreign operations; the cyclical nature of the industry in which we operate; risks related to failure to obtain adequate financing on a timely basis and on acceptable terms or delays in obtaining governmental approvals; risks related to environmental regulation and liability; political and regulatory risks associated with mining and exploration; risks related to the certainty of title to our properties; risks related to the uncertain global economic environment; and other risks and uncertainties related to our prospects, properties and business strategy, as described in more detail in Plateau Uranium’s recent securities filings available at www.sedar.com. Actual events or results may differ materially from those projected in the forward-looking statements and Plateau cautions against placing undue reliance thereon. Neither Plateau nor its management assume any obligation to revise or update these forward-looking statements.

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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