Last checked at 16 Jun 2017 09:00
Premier African Minerals Limited / Ticker: PREM / Index: AIM / Sector: Mining
For immediate release
16 June 2017
Premier African Minerals Limited
("Premier" or the "Company")
Excellent Metallurgical Testwork Results on Zulu
Premier African Minerals Limited, the AIM-traded, multi-commodity resource and development Company focused on Southern and Western Africa, is pleased to report excellent results from the initial metallurgical test work study on its wholly-owned Zulu Lithium and Tantalum project ("Zulu") in Zimbabwe. The test work was completed by German based Dorfner Anzaplan GmbH ("Dorfner"), a leading authority in the field of lithium and speciality minerals processing and treatment.
The Company will continue with additional test work to improve the recoveries of lithium and associated minerals as well as improve the flowsheet design and establishing capital and operating costs for producing lithium from Zulu.
Highlights:
· The best flotation test work on spodumene pegmatite achieved an overall lithium recovery of 81.8% and a concentrate containing 6.5% Li₂O and 0.09% Fe2O3. This is well within the typical range of spodumene concentrates for glass and ceramics as well as feedstock for conversion to lithium carbonate
· The best flotation test work on a mixed pegmatite sample achieved a spodumene concentrate containing 5.9% Li₂O being acceptable for spodumene concentrates as feed stock for lithium carbonate production and a commercial grade petalite concentrate containing 3.9% Li2O at exceptionally low Fe2O3 content of
· The tailings of spodumene and petalite flotation process contain very low iron oxide concentrations in the range of 0.01%, offering the potential for producing a high quality, low iron feldspar and quartz as by-products for glass and ceramics applications
· Further metallurgical test work is planned including tests on the recoveries of lithium bearing minerals, the recovery of a saleable tantalite concentrates and high purity, low iron oxide quartz and feldspar concentrates as well as optimise flowsheet design.
· Dorfner also recommend a test work programme for lithium extraction to produce lithium carbonate and hydroxide to prove that marketable lithium carbonate and hydroxide can be produced
George Roach, Chairman and CEO commented: "We are very excited with these excellent initial metallurgical test work results. These results demonstrate that we can produce a commercial grade, high quality lithium mineral concentrates from both the spodumene and petalite mineralisation at Zulu project. We will continue to conduct further testing to optimise the recoveries and grades, as well as improving the flowsheet design for the Zulu project."
The metallurgical test work results and the recently announced a maiden Inferred Mineral Resource Estimate at Zulu of 20.1 million tonnes grading 1.06% Li2O on only a part of the 3.5km strike length of the Zulu project again confirm that the Zulu project has all the hallmarks of a world-class lithium project."
Metallurgical Test Work
The test work was completed by German-based Dorfner Anzaplan GmbH ("Dorfner"). Dorfner is a leading authority in the high purity industrial and strategic minerals and metals businesses, providing a multitude of services, such as materials testing and analysis, industry expertise and market intelligence, basic and advanced engineering services. For more information of Dorfner, please visit: http://www.anzaplan.com/
The Executive Summary reproduced below has been extracted without material adjustment or amendment from Dorfner's final report on the Physical Processing of Lithium Pregmatite Ore from the Zulu Pegmatite, Zimababwe dated 9 June 2017:
Executive Summary
Premier African Minerals, South Africa is in the process of evaluating its Zulu Lithium Project in Zimbabwe developing a beneficiation process for the lithium ore. The primary objective of the present beneficiation test work was to develop a flow sheet for lithium mineral concentration
including the following main items:
· Sensor based sorting of lithium ore to separate dominantly petalite and spodumene ore
· Process development on samples after sensor based sorting for spodumene and petalite mineral concentration
· Laboratory heavy liquid separation (HLS), to evaluate the amenability of the ore for dense media separation (DMS)
Three samples, labeled "Zulu Surface", "Zulu Adit", and "Zulu Petalite" in the amount of 868 kg in total from the Zulu pegmatite deposit were sampled by Premier African Minerals and sent to Dorfner ANZAPLAN for processing tests. Sample "Zulu surface" is strongly altered. It was therefore decided in consultation with Premier African Minerals to not consider sample "Zulu surface" in present test work. For the processing test work, a mixed sample of "Zulu Adit" and "Zulu Petalite" was prepared
in a mixing ratio of 1:1 with a lithium oxide grade of the combined sample of 1.1 wt.-%.
Sensor based sorting
Target of the sensor based sorting test work was to separate spodumene rich ore from petalite rich ore as spodumene and petalite require different flotation regimes.
For sorting the sample was crushed to -80 mm and screened into fractions +3 -8 mm, +8 -25 mm, +25 mm for sorting and fines -3 mm. A two stage optical sorting process was tested on the ore sample in three size fractions (+3 -8 mm, +8 -25 mm, +25 mm). From each size fraction, a spodumene rich fraction, intermediate product and a petalite rich fraction was generated.
Based on the result of chemical and mineralogical analyses of all fractions received after sensor based sorting, the following two samples were combined for further processing tests:
· A spodumene rich pre-concentrate containing no petalite ("spodumene ore sample") with a Li2O grade of 1.5 wt.-% containing 51 wt.-% of overall lithium oxide in 38 wt.-% of mass.
· A "mixed ore sample" containing the intermediate product and the petalite rich fraction with a Li2O grade of 0.9 wt.-% containing 49 wt.-% of overall lithium oxide in 62 wt.-% of mass.
Flotation test work
Mineral processing tests were carried out individually on the two ore samples after sensor based sorting. The spodumene dominated sample "spodumene ore sample" was subjected to spodumene flotation. For the "mixed ore sample", spodumene and subsequently petalite flotation was carried out as both minerals require different flotation regimes.
In case of spodumene ore, the best results in terms of overall recovery were calculated for test F4. A spodumene concentrate with 5.5 wt.-% Li2O in the rougher flotation concentrate at an overall lithium recovery of 83.7 wt.-% was achieved. The rougher concentrate was upgraded in one cleaner stage to a concentrate with 6.5 wt.-% Li2O at 81.8 wt.-% recovery in cleaner concentrate 1. Additionally, only a low amount of lithium (1.9 wt.-%) is in the cleaner tails, which are recirculated in the technical
process. Most of the lithium in the cleaner tails should also be recoverable.
Thus an indicative estimate for overall lithium flotation recovery is in the range of 83 wt.-% at a Li2O grade of 6.5wt.-%. This has to be approved in locked cycle tests in future test work. Definitive losses of lithium oxide are in slimes (4.3 wt.-%), mica concentrate (8.1 wt.-%) and spodumene flotation tails (3.9 wt.-%), which sum up to 16.3 wt.-%. In contrast to the spodumene ore sample, the lithium grade in the mixed sample is significantly lower (0.9 wt.-% after sorting). The mixed ore sample contains about 5 wt.-% spodumene and 12 wt.-% petalite resulting in a lithium distribution of approx. 60 wt.-% Li2O in petalite and 40 wt.-% in spodumene In the case of the mixed ore sample, the best results in terms of overall recovery at grades in the range of typical products were achieved in flotation test F15. There, 35.1 wt.-% of the lithium contained in the sample was recovered in the spodumene cleaner concentrate at a grade of 5.8 wt.-% Li2O in 6.5 wt.-% of the mass. In addition, 17.4 wt.-% of the
lithium contained in the sample was recovered in the subsequent petalite cleaner concentrate at a grade of 3.9 wt.-% Li2O in 4.8 wt.-% of the mass.
In this test a relatively high amount of the lithium reports to the cleaner tails (in total 28.6 wt.-%) deriving mainly from petalite flotation (21.3 wt.- %) as well as a minor quantity from spodumene flotation (7.3 wt.-%). These cleaner tailings are recirculated in the technical process. This implies that most of the lithium in these cleaner tails should also be recoverable. However, overall lithium recovery of the mixed ore sample in continuous process is assumed lower, and is estimated to be in a range of
about 70 wt.-%. Again, this has to be approved in locked cycle flotation tests in future test work.
Definitive losses of lithium are observed in the best test for the mixed ore sample in the slimes (4.5 wt.-%), mica concentrate (8 wt.-%) and petalite tails (6.4 wt.-%). Minor additional losses of lithium are in the cleaner tails 5 (0.9 wt.-%), which have to be removed from the process to separate quartz and cannot be recirculated. Therewith definitive losses sum up to 19.8 wt.-% for the mixed ore sample.
Mineral concentrates
Best results in spodumene concentrate quality were achieved with the spodumene ore sample in test F4. There a spodumene concentrate at 6.5 wt.-% Li2O and an iron oxide concentration of 0.09 wt.-% was
achieved, being well within the typical range of spodumene concentrates for glass and ceramics as well as feedstock for conversion to lithium carbonate. In the case of a mixed ore sample a spodumene concentrate grading 5.9 wt.-% Li2O was obtained at an iron oxide content in the range of 0.6 wt.-% being acceptable for spodumene as feed stock for lithium carbonate production. Introducing an additional magnetic separation step an iron oxide content of 0.16 wt.-% was achieved, being only slightly elevated compared to typical standard glass grade spodumene products. The best petalite concentrate was generated in test F15 resulting in a Li2O grade of 3.9 wt.-% being in the range of typical petalite concentrate grades of 4 wt.-% Li2O content. The benefit of petalite from the Zulu
deposit is the exceptionally low iron oxide content. In the best petalite concentrate an iron oxide value of in typical products was analyzed being beneficial with respect to glass and ceramics application.
Recommended flow sheet
Based on test work results a flow sheet is recommended comprising the following main processing steps:
· Based on HLS test results it appears feasible that using DMS it is possible to produce a spodumene enriched heavy fraction containing only spodumene besides quartz, feldspar and other non lithium bearing silicates. The light fraction from DMS represents the mixed ore fraction being enriched in lithium minerals, mainly petalite and some residual spodumene. In addition a middle fraction, depleted in lithium, can be rejected for mass reduction prior to flotation. However, this has to be confirmed in pilot DMS tests.
· Separate processing of spodumene and mixed ore after DMS is suggested to be processed in the same plant, however with alternating feed. This offers the advantage that the spodumene ore has to be treated only up to spodumene flotation.
· The ore sample is crushed and ground to target grind size (150 μm) and then deslimed by hydro cyclone. The deslimed ore is used as feed material for flotation.
· Magnetic separation of mixed ore in case low iron glass grade spodumene is targeted to be produced.
· Mica flotation to provide purified feed material for subsequent spodumene flotation, being necessary to achieve high grade spodumene concentrates.
· Spodumene flotation to produce a high grade spodumene concentrate.
· In case of mixed ore: Further processing of spodumene flotation tailings to produce a petalite concentrate.
Recommendations
Based on the results of present test work, the following recommendations are made for future metallurgical testing to develop the lithium project:
· Dense media separation test work for pre-concentration and separation into spodumene and petalite enriched fractions.
· Flotation tests on samples from DMS are recommended especially for petalite flotation to investigate potential improvements (improved petalite grade and simplification of petalite flotation process)
· Conduct locked cycle test work for spodumene and petalite flotation to confirm overall flotation recoveries and the influence on concentrate grade and recovery when recirculating cleaner tailings.
· It is recommended to investigate the lithium mineral distribution within the deposit, to evaluate if petalite and spodumene ore can be mined selectively.
· In tailings of spodumene and petalite flotation respectively very low iron oxide concentrations in the range of 0.01 wt.-% were analyzed. Production of high quality, low iron feldspar and quartz by-products
· for glass and ceramics applications appear feasible. It is recommended to investigate if there is a local market for such products in Zimbabwe or surrounding countries. If this is the case test work to produce quartz and feldspar by-products is recommended.
· A test work program for lithium extraction to produce lithium carbonate and hydroxide is recommended to prove that marketable lithium carbonate and hydroxide can be produced from spodumene respectively petalite concentrates from the Zulu deposit.
· An ore variability study is recommended to investigate the impact of varying feed composition on grade and recovery of flotation.
· Finally an economic evaluation of the project in a scoping study or preliminary economic assessment (PEA) is recommended to further develop the Zulu lithium project.
Glossary of Technical Terms:
Fe2O3 | is the chemical formula of iron oxide |
Flotation | is a process for selectively separating hydrophobic materials from hydrophilic. This is used in mineral processing, paper recycling and waste-water treatment industries |
"Inferred Resource" | that part of a Mineral Resource for which tonnage, grade and mineral content can be estimated with a low level of confidence. It is inferred from geological evidence and sampling and assumed but not verified geological and/or grade continuity. It is based on information gathered through appropriate techniques from locations such as outcrops, trenches, pits, workings and drill holes that may be limited or of uncertain quality and reliability |
"K-feldspar" | is a general term for potassium bearing feldspars KAlSi3O8, a common rock forming mineral |
"Lepidolite" | is the mineral name for lithium bearing mica KLi2Al(Si4O10)(F,OH)2 an important ore of lithium |
"Li2O" | chemical formula of lithium oxide |
"Lithium Carbonate Equivalent (LCE)" | is the industry standard terminology for, and is equivalent to, Li2CO3 |
"Measured mineral resource" | that part of a mineral resource for which quantity, grade or quality, densities, shape, and physical characteristics are so well established that they can be estimated with confidence sufficient to allow the appropriate application of technical and economic parameters, to support production planning and evaluation of the economic viability of the deposit. The estimate is based on detailed and reliable exploration, sampling and testing information gathered through appropriate techniques from locations such as outcrops, trenches, pits, workings and drill holes that are spaced closely enough to confirm both geological and grade continuity |
"Mica" | is a general term for a group of sheet silicate minerals, it includes several closely related minerals having nearly perfect basal cleavage, KAl2(Si3Al)O10(OH,F)2; micas are common rock forming minerals. |
"Mineral resource" | concentration or occurrence of diamonds, natural solid inorganic material or natural fossilized organic material including base and precious metals, coal, and industrial minerals in or on the Earth's crust in such form and quantity and of such a grade or quality that it has reasonable prospects for economic extraction. The location, quantity, grade, geological characteristics and continuity of a mineral resource are known, estimated or interpreted from specific geological evidence and knowledge. |
"Pegmatite" | an exceptionally coarse-grained igneous rock, with interlocking crystals, usually found as irregular dikes, lenses, or veins, esp. at the margins of granitic intrusions |
"Petalite" | the mineral name for lithium aluminium silicate LiAl(Si4O10) an important ore of lithium. |
"ppm" | means parts per million |
"Quartz" | one of the most common rock forming minerals with the chemical composition SiO2 (silicon dioxide) |
"Spodumene" | the mineral name for lithium aluminium silicate LiAlSi2O6 an important ore of lithium. |
"Ta2O5" | chemical formula of ditantalum pentoxide |
"Tantalum pentoxide" | is the inorganic compound with the formula Ta2O5, |
"Tantalite" | a mostly dark grey to black mineral, manganese bearing varieties are called manganotantalite or tantalite-(Mn) MnTa2O6; a major tantalum ore. |
wt.-% | is weight percent |
Forward Looking Statements:
Certain statements in this announcement, are, or may be deemed to be, forward looking statements. Forward looking statements are identified by their use of terms and phrases such as ''believe'', ''could'', "should" ''envisage'', ''estimate'', ''intend'', ''may'', ''plan'', ''will'' or the negative of those, variations or comparable expressions, including references to assumptions. These forward-looking statements are not based on historical facts but rather on the Directors' current expectations and assumptions regarding the Company's future growth, results of operations, performance, future capital and other expenditures (including the amount, nature and sources of funding thereof), competitive advantages, business prospects and opportunities. Such forward looking statements reflect the Directors' current beliefs and assumptions and are based on information currently available to the Directors. A number of factors could cause actual results to differ materially from the results discussed in the forward-looking statements including risks associated with vulnerability to general economic and business conditions, competition, environmental and other regulatory changes, actions by governmental authorities, the availability of capital markets, reliance on key personnel, uninsured and underinsured losses and other factors, many of which are beyond the control of the Company. Although any forward-looking statements contained in this announcement are based upon what the Directors believe to be reasonable assumptions, the Company cannot assure investors that actual results will be consistent with such forward looking statements.
Competent Persons Statement:
The information in this announcement that relates to the Mineral Resource Estimate is based on data compiled and verified by Wolfgang Hampel. Wolfgang Hampel, Exploration Manager of Premier African Minerals Limited has reviewed and approved this release to the extent that reference is made to the Zulu tenements. Mr Hampel has 26 years' relevant experience in the African, American, European and Asian exploration and mining industry and holds a Diploma in Economic Geology (Dipl.-Geol.) from the Technical University of Munich. He is a registered European Geologist (EurGeol), n° 1261, with the European Federation of Geologists. Mr Hampel has sufficient experience which is relevant to the style of mineralisation and types of deposits under consideration, and to the activity which has been undertaken, to qualify as a Competent Person as defined by the 2007 edition of the South African Code for Reporting of Exploration Results, Mineral Resources and Mineral Reserves (SAMREC). Mr Hampel has reviewed and approved this announcement and the commentary above to the extent reference is made to geological resource and resource grade and accepts responsibility for the accuracy of these statements disclosed in this announcement.
This announcement contains inside information for the purposes of Article 7 of EU Regulation 596/2014.
Enquiries:
Fuad Sillem | Premier African Minerals Limited | Tel: +44 (0)7734 922074 |
Michael Cornish / Roland Cornish | Beaumont Cornish Limited (Nominated Adviser) | Tel: +44 (0) 207 628 3396 |
Jerry Keen/Edward Mansfield | Shore Capital Stockbrokers Limited | Tel: +44 (0) 207 408 4090 |
Jon Belliss | Beaufort Securities Limited | Tel: +44 (0) 20 7382 8300 |
Charles Goodwin/ Harriet Jackson | Yellow Jersey PR Limited | Tel: +44 (0) 7747 788221 |
Notes to Editors:
Premier African Minerals Limited (AIM: PREM) is a multi-commodity mining and natural resource development company focused in Southern and Western Africa with production started at its flagship RHA project in Zimbabwe.
The Company has a diverse portfolio of projects, which include tungsten, rare earth elements, gold, lithium and tantalum in Zimbabwe and Benin, encompassing brownfield projects with near-term production potential to grass-roots exploration. The Company recently acquired a 52% controlling stake in Mozambique-based TCT Industrias Florestais Limitada, which owns a substantial limestone deposit and forestry business located on rail in the Sofala Province of Mozambique. In addition, the Company holds 2 million shares in Circum Minerals Limited ("Circum"), the owners of the Danakil Potash Project in Ethiopia, which has the potential to be a world class asset. At present those shares are valued at US$4 million based on the latest price at which Circum has accepted subscriptions. Premier also has an interest in Casa Mining Limited, a privately-owned exploration company that has a 71.25% interest in the 1.2 million ounce inferred resource Akyanga gold deposit in the DRC.
ENDS