NORTH SYDNEY, Australia, April 12, 2018 (GLOBE NEWSWIRE) --
Highlights
- Rapidly advancing 100%-owned Rhyolite Ridge Lithium-Boron Project (“Project”) in the USA towards development
- Latest results from ongoing optimisation of acid-leach testwork on Rhyolite Ridge lithium-boron mineralisation show leach time and recoveries can both be improved by reducing the crush size:
- Column leach time reduced from 41 to 15 days – a 60% reduction
- Recoveries to solution increased to 97% for lithium and 98% for boron
- Column leach time reduced from 41 to 15 days – a 60% reduction
- Vat leach testwork returned high recoveries of both lithium (92%) and boron (80%)
- Further improvements for vat and column tests likely with ongoing optimisation testwork
- Amec Foster Wheeler (“Amec”) appointed as the engineering and design firm to complete the Rhyolite Ridge Pre-Feasibility Study (“PFS”)
- Trade-off studies currently being carried out by Amec will enable selection of the most favourable processing and infrastructure options
- Global’s Rhyolite Ridge is the only lithium deposit in the world that has been demonstrated to be amenable to simple acid leach processing, reinforcing it as a credible alternative to spodumene and brine deposits as a major, low-cost and long-term source of lithium
- Global Geoscience was included in the S&P/ASX 300 Index during the quarter
Overview
Global Geoscience is focussed on developing its 100%-owned Rhyolite Ridge Lithium-Boron Project in Nevada, which is at the Pre-Feasibility Study (PFS) stage.
Global’s Managing Director, Bernard Rowe, commented on the March 2018 quarter:
“The Rhyolite Ridge PFS is progressing well under the direction of Amec Foster Wheeler. The unique mineralogy and chemistry of the Rhyolite Ridge mineralisation continues to provide many attractive options which consistently point to low-cost processing and high recoveries of lithium and boron.
“Phase One of the PFS includes trade-off studies to determine the most favourable processing and infrastructure alternatives. Key aspects of this work have been to evaluate and compare the various leaching options – heap, vat and agitation (tank) leaching and on-site production of sulphuric acid.
“The unique Rhyolite Ridge mineralogy enables the lithium and boron minerals to be readily dissolved in sulphuric acid – meaning high recoveries and short leach times with acceptable sulphuric acid consumption.
“In December we announced the significant breakthrough of Rhyolite Ridge mineralisation being amenable to heap leaching based on the initial column leach testwork. Further results announced during the quarter provided significantly faster leach times by simply reducing the feedstock crush size to minus 38mm from the minus 150mm in earlier tests. Recoveries to solution also improved to near-maximum levels.
“This testwork has further demonstrated that acid leaching is likely to be a simple, low-cost processing route for this unique lithium-boron mineralisation.
“The initial mining study has shown that the current high-grade lithium-boron Resource can readily support a long-life 2Mtpa to 4Mtpa mining operation.
“We are delighted with the rapid progress of our unique Rhyolite Ridge Lithium-Boron project in Nevada, and this has now been reflected in the Company’s inclusion in the S&P/ASX 300 Index.
“Planned to be completed in mid-2018, the Rhyolite Ridge PFS is expected to provide confirmation of our view that we have an economic pathway to develop the Rhyolite Ridge deposit into a significant, low-cost, near-term producer of lithium carbonate and boric acid in America.”
Rhyolite Ridge is a large, shallow lithium-boron deposit located close to existing infrastructure in southern Nevada, USA. The Project lies 25km west of Albermarle’s Silver Peak lithium mine and 340km from the Tesla Gigafactory near Reno. Rhyolite Ridge is one of the largest lithium and boron deposits in the world and has the potential to become a strategic, long-life and low-cost source of lithium and boron.
Rhyolite Ridge is very well positioned to become a major US domestic producer capable of supplying a significant portion of future American lithium demand. This strategic location was reinforced on 20 December 2017 when President Trump signed an Executive Order titled a “Federal Strategy to Ensure Secure and Reliable Supplies of Critical Minerals”. Lithium is one of the 23 critical mineral resources previously identified by the United States Geological Survey.
The Rhyolite Ridge Advantage
The unique mineralogy of Rhyolite Ridge is what sets it apart from other lithium and lithium-boron deposits. Unlike other sedimentary and pegmatite (spodumene, mica) lithium deposits, the lithium (and boron) at Rhyolite Ridge are contained within minerals that are highly soluble in sulphuric acid. Compared to other sedimentary lithium deposits, the lithium-boron mineralisation at Rhyolite Ridge has very low clay content.
These unique characteristics mean that Rhyolite Ridge mineralisation is amenable to simple, low-cost acid leaching – including heap, vat and agitation (tank) leach. Unlike other sedimentary and pegmatite lithium deposits, Rhyolite Ridge does not require roasting or high-temperature conversion prior to acid leaching, meaning significantly lower operating and capital costs.
The deposit is amenable to low-cost open pit mining methods. The high-grade lithium-boron mineralisation is the focus of the Rhyolite Ridge PFS as it represents potentially the highest value material combined with a low-cost, simple processing route. This is due to the low-clay, low-carbonate and high-searlesite (boron) content of the rock, which make the mineralisation amenable to low-cost acid leaching at ambient temperature and pressure. The proposed flowsheet will allow for the production of lithium carbonate/hydroxide and boric acid at the mine site.
Key advantages include:
- Nevada location: one of the world’s most favourable and stable mining jurisdictions and home to the USA’s burgeoning electric vehicle industry. Nevada has well-developed infrastructure and skilled mining workforce
- Unique mineralogy which distinguish it from other sedimentary lithium deposits and allow for a simple, low-cost acid leach extraction process. Unlike sedimentary clay deposits, no roasting or calcining is required
- Unlike pegmatite (spodumene, mica) deposits, no high-temperature conversion is required to produce lithium carbonate
- Dual revenue streams from lithium and boron
- Simple ownership – 100% Global Geoscience with no private royalties
- Large Mineral Resource containing 137 million tonnes of high-grade lithium-boron mineralisation within a total Resource (Indicated & Inferred) of 460 million tonnes
- PFS planned to be completed in mid-2018
- Management and technical team with proven track record in the development and delivery of lithium and boron projects
- Ideally positioned to supply the lithium and boron markets in the USA and Asia
- Potential long-term US domestic supplier of lithium – a designated critical mineral
Project Development Activities
Appointment of Amec Foster Wheeler for PFS
On 17 January 2018, the Company announced the appointment of Amec Foster Wheeler (“Amec”, part of Wood plc) as the engineering and design firm to complete the Rhyolite Ridge PFS.
A key aspect of Amec’s selection was its strong technical team and recent, highly relevant experience in lithium and boron projects. The Amec team members for the Rhyolite Ridge PFS are based in Vancouver, Reno and Santiago.
The PFS work is being carried out in two phases – a definition phase, including trade-off studies, to identify the major process and infrastructure components required and a pre-feasibility phase involving mine and engineering design and cost estimation. The PFS work is progressing well and according to plan.
PFS Studies and Permitting
Rhyolite Ridge is located on federal government land administered by the Bureau of Land Management (“BLM”) and the Company has formally commenced the permitting process with the BLM. The initial submission includes a preliminary site layout plan. Permitting will require completion of either an Environmental Assessment (“EA”) or an Environmental Impact Statement (“EIS”) as determined by the BLM. Rhyolite Ridge may be eligible for a fast-track EA permit as the footprint of the project submitted to the BLM is less than one square mile.
Biological and cultural studies completed by previous owners remain valid. Work is underway to update and extend these studies. Groundwater, geochemical and geotechnical studies have commenced.
RPM Global has commenced mine planning and mine design work for the PFS. The basis of this work is the high-grade (lithium-boron) component of the South Basin Mineral Resource published in October 2017.
Metallurgical Testwork
Ongoing metallurgical testwork conducted by Hazen Research (Denver) and Kappes Cassiday (Reno) has further demonstrated that simple, low-cost acid leach processes can be used to extract lithium and boron at high recovery rates into a Pregnant Leach Solution (“PLS”). Lithium and boron can then be removed from the PLS through crystallisation and purification steps to produce lithium carbonate/hydroxide and boric acid at the mine site.
The table below compares the key results announced on 21 February 2018 (Column 4 and Vat 1) with the key results announced on 12 December 2017 (Columns 2 and 3).
| Heap Leach Column 2 | Heap Leach Column 3 | Heap Leach Column 4 | Vat Leach Vat 1* | |
| Crush | -150mm | -150mm | -38mm | -150mm |
| Lithium Recovery to PLS | 90% | 92% | 97% | 92% |
| Boron Recovery to PLS | 88% | 89% | 98% | 80%* |
| Leach Time | 41 days | 41 days | 15 days | 39 days* |
| Acid Pre-treatment | 10% | 15% | 5% | 15% |
| Acid Leach Solution | 10% | 10% | 10% | 15% |
| Acid Consumption (kg/t of ore) | 413 | 460 | 485 | 446 |
* Vat 1 represents a preliminary vat test and significant increase in boron recovery and decrease in leach time are expected with further vat testwork based on the initial results obtained.
Since the Rhyolite Ridge lithium-boron mineralisation responds extremely well to acid leaching, Amec is currently evaluating various processing flowsheets to determine the best route to proceed with in the PFS. The processing routes being evaluated in this trade-off study include agitation (tank) leaching, vat leaching and heap leaching.
On-going metallurgical testwork is also analysing various options for the crystallisation and purification process steps. The crystallisation and purification testwork has been evaluating the best sequence to precipitate minerals and has succeeded in separating minerals simply by adjusting temperature, pH and concentration of the solution. Proceeding in parallel is further testwork evaluating a range of acid leaching parameters.
Heap and Vat Leaching Background
Heap or vat leach extraction of lithium and boron at modest acid consumption rates means significantly lower capital and operating costs are likely when compared to other forms of acid leaching such as agitation (tank) leaching that require crushing, grinding, filtration and leach tanks. It also means substantially lower capital and operating costs when compared to hard-rock lithium deposits (spodumene, mica, clay) that require beneficiation and high temperature conversion or roasting to liberate the lithium prior to the lithium carbonate production process.
The Company believes Rhyolite Ridge is the first lithium project where heap leach has been demonstrated to be an effective processing route.
The key results from the heap leach testwork were:
- High recoveries to PLS: up to 97% for lithium and 98% for boron
- Large samples: 58kg to 495kg
- Coarse feed: crushed to minus 38mm
- Rapid leach times: 15 days to get circa 97% recoveries to solution
- Moderate net acid consumption: 485kg per tonne of ore
- High permeability and high percolation rates maintained throughout tests
- Excellent column integrity: low mass loss (21%) and low slumping (<5%)
- PLS can be operated at close to boric acid saturation
- No agglomeration required
A simplified overview of the heap leach flowsheet for Rhyolite Ridge is provided in the diagram below.
A photo accompanying this announcement is available at http://resource.globenewswire.com/Resource/Download/19e2ebdd-ed17-4a9b-bab6-30ee66455e00
A heap or vat leach operation at Rhyolite Ridge would likely involve the following:
- Run-of-mine ore is crushed to between 30mm and 150mm
- The crushed ore is placed on a lined pad or within a large vat
- The ore is irrigated with sulphuric acid/water solution via drip feeder pipes (heap) or flooded (vat)
- The metals are dissolved into solution, forming a pregnant leach solution (“PLS”)
- The PLS is collected in a pond or tank
- Boron and lithium are recovered from the PLS and converted into boric acid and lithium carbonate or hydroxide by a combination of crystallisation and purification process steps
June Quarter Work Program
The June quarter work program will continue to focus on aspects of the Rhyolite Ridge PFS including:
- Completion of Phase 1 of PFS (trade-off studies)
- Commencement of Phase 2 of PFS – mine and engineering design and cost estimates
- Optimisation of acid-leach process
- Crystallisation and purification testwork on PLS to produce lithium and boron end products
- Progressing the permitting process and associated environmental, groundwater and geotechnical studies
The PFS is planned to be completed in mid-2018.
Corporate Activities
S&P/ASX 300 Index
On 19 March 2018, Global Geoscience was included in the S&P/ASX 300 Index.
The Company’s share price increased from $0.350/share to $0.475/share during the quarter, with a market capitalisation of $634 million at the end of the quarter.
Expenditure
Expenditure during the March quarter totalled:
- $1.2 million on exploration; and
- $0.5 million on corporate/administration/salaries.
Cash on hand at 31 March 2018 was $33.6 million.
Capital Structure
Following the achievement of performance hurdles, a total of 14 million performance rights were converted to ordinary shares during the quarter. A total of 10.4 million unlisted options were exercised during the quarter, raising $2.1 million.
At the end of the quarter, Global Geoscience had on issue:
- 1.34 billion ordinary shares;
- 58.1 million options; and
- 1.5 million performance rights.
Contacts at Global Geoscience
| Bernard Rowe | James D. Calaway | Roger Howe |
| Managing Director | Chairman | Investor Relations |
| T: +61 419 447 280 | T: +1 713 818 1457 | T: +61 405 41 9 139 |
| E: browe@globalgeo.com.au | E: jcalaway@calawayinterests.com | E: rhowe@globalgeo.com.au |
About Global Geoscience
Global Geoscience Limited (ASX:GSC) is an Australian-based lithium-boron mine developer focused on its 100%-owned Rhyolite Ridge Lithium-Boron Project in Nevada, USA. Rhyolite Ridge is a large, shallow lithium-boron deposit located close to existing infrastructure. It is a unique sedimentary deposit that has many advantages over the brine and pegmatite deposits that currently provide the world’s lithium. The Rhyolite Ridge Pre-Feasibility Study is in progress.
Global Geoscience is aiming to capitalise on the growing global demand for lithium and boron. Lithium has a wide variety of applications, including pharmaceuticals, lubricants and its main growth market, batteries. Boron is used in glass, fiberglass, insulation, ceramics, semiconductors, agriculture and many other applications. Global Geoscience aims to develop the Rhyolite Ridge Lithium-Boron Project into a strategic, long-life, low-cost supplier of lithium and boron products. To learn more please visit: www.globalgeo.com.au.
Recent Announcements
The table below lists announcements made by the Company during the quarter.
| Date Released | Title |
| 17 January 2018 | Global Geoscience appoints Amec Foster Wheeler for Rhyolite Ridge PFS |
| 24 January 2018 | Activities and Cashflow Reports for December 201 Quarter |
| 20 February 2018 | Corporate Governance Policies |
| 21 February 2018 | Optimisation Success Reduces Leach Time by 60% |
| 28 February 2018 | Half-Year Financial Report for Period Ending 31 December 2017 |
| 19 March 2018 | Global Geoscience Joins S&P/ASX 300 Index and Provides Rhyolite Ridge Update |
| 21 March 2018 | Letter to Shareholders |
Compliance Statement
The information in this report that relates to Exploration Results is based on information compiled by Bernard Rowe, a Competent Person who is a Member of the Australian Institute of Geoscientists. Bernard Rowe is a shareholder, employee and Managing Director of Global Geoscience Ltd. Mr Rowe has sufficient experience that is relevant to the style of mineralisation and type of deposit under consideration and to the activity being undertaken to qualify as a Competent Person as defined in the 2012 Edition of the ‘Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves’. Bernard Rowe consents to the inclusion in the report of the matters based on his information in the form and context in which it appears.
In respect of Mineral Resources referred to in this report and previously reported by the Company in accordance with JORC Code 2012, the Company confirms that it is not aware of any new information or data that materially affects the information included in the public report titled “Global Geoscience Doubles High-Grade Lithium-Boron Mineral Resource” dated 31 October 2017 and released on ASX. Further information regarding the Mineral Resource estimate can be found in that report. All material assumptions and technical parameters underpinning the estimates in the report continue to apply and have not materially changed.
Forward Looking Statements
Various statements in this report constitute statements relating to intentions, future acts and events which are generally classified as “forward looking statements”. These forward looking statements are not guarantees or predictions of future performance and involve known and unknown risks, uncertainties and other important factors (many of which are beyond the Company’s control) that could cause those future acts, events and circumstances to differ materially from what is presented or implicitly portrayed in this presentation. Words such as “anticipates”, “expects”, “intends”, “plans”, “believes”, “seeks”, “estimates”, “potential” and similar expressions are intended to identify forward-looking statements.
Global cautions security holders and prospective security holders to not place undue reliance on these forward-looking statements, which reflect the view of Global only as of the date of this report. The forward-looking statements made in this report relate only to events as of the date on which the statements are made. Except as required by applicable regulations or by law, Global does not undertake any obligation to publicly update or review any forward-looking statements, whether as a result of new information or future events. Past performance cannot be relied on as a guide to future performance.
Appendix
Geology
The Rhyolite Ridge project covers two separate lithium-boron deposits (North Basin and South Basin) located 4km apart. The mineralisation occurs in flat lying sedimentary rocks as two or more stacked layers or lenses. The sedimentary rocks are up to 300m thick and the mineralised layers within are 20-70m thick. The mineralised layers contain lithium only (clay-rich) and lithium-boron (clay-poor) mineralisation.
The lithium-only mineralisation typically contains over 2000ppm lithium, less than 0.02% boron and occurs in clay-rich layers. The lithium-boron mineralisation typically contains 1500-2000ppm lithium and greater than 1% boron, is higher in silica, sodium and potassium and lower in calcium and magnesium and occurs in 20m to 70m thick layers containing abundant searlesite (20-40%) and low clay content. Searlesite is a sodium-boron-silicate mineral. There are at least two separate layers of lithium-boron mineralisation (upper zone and lower zone) separated by 30-50m of barren sediments. The upper zone outcrops and the lower zone is shallow (<40m) along the western margin of South Basin. Both types of mineralisation are very consistent laterally over at least several square kilometres.
The host rocks are dominated by the minerals searlesite (boron-bearing), sepiolite (lithium-bearing), K-feldspar, calcite and dolomite. Unlike most other sedimentary-type lithium deposits, the lithium-boron mineralisation at Rhyolite Ridge has low clay content.
Both basins have not been significantly structurally disturbed since deposition and the strata/mineralisation are very consistent laterally.
Resource Estimate
The Indicated and Inferred Resource estimate for the South Basin at Rhyolite Ridge totals 460 million tonnes at 0.9% lithium carbonate and 2.6% boric acid (at a 1,050ppm Li cut-off). This includes both the high-grade lithium-boron mineralisation and the lower grade lithium only (clay-rich) mineralisation.
A photo accompanying this announcement is available at http://resource.globenewswire.com/Resource/Download/ee54ed40-9874-4797-a40a-f73c0d08d898
The Indicated and Inferred Resource includes a high-grade lithium-boron zone totalling 137 million tonnes at 0.9% lithium carbonate and 7.2% boric acid (at a 1,050ppm Li and 0.5% B cut-off).
A photo accompanying this announcement is available at http://resource.globenewswire.com/Resource/Download/9abd483f-89b1-420c-84dd-c4c3e952a8c7
Lithium and boron conversion factors
Lithium and boron grades are fundamentally presented in parts per million (“ppm”) or percentages of each element in a given sample or estimate.
Lithium and boron grades are also expressed as various compounds in percentages in order to facilitate comparisons between different types of deposits and/or various products.
The conversion factors presented below are calculated on the atomic weights and number of atoms of each element in the various compounds.
The standard lithium conversion factors are set out in the table below:
| Convert from | Convert to Li (lithium) | Convert to Li2O (lithium oxide) | Convert to Li2CO3 (lithium carbonate) | |
| Lithium | Li | 1.000 | 2.152 | 5.322 |
| Lithium Oxide | Li2O | 0.465 | 1.000 | 2.473 |
| Lithium Carbonate | Li2CO3 | 0.188 | 0.404 | 1.000 |
Lithium (chemical symbol: Li) is the lightest of all metals and the third element in the periodic table. The element lithium does not exist by itself in nature but is contained within mineral deposits or salts including brine lakes and sea water.
Lithium Carbonate Equivalent (“LCE”) is often used to present the amount of contained lithium in a standard manner, i.e. – to provide an equivalent amount of lithium expressed as lithium carbonate. The use of LCE is to provide data comparable with industry reports. The LCE grades reported in the Company’s Mineral Resource estimates are calculated using the conversion factors in the table above and assume 100% of the contained lithium is converted to lithium carbonate. The LCE values quoted in this report do not include boron nor any other elements.
The standard boron conversion factors are set out in the table below:
| Convert from | Convert to B (boron) | Convert to B2O3 (boric oxide) | Convert to H3BO3 (boric acid) | |
| Boron | B | 1.000 | 3.219 | 5.718 |
| Boric Oxide | B2O3 | 0.311 | 1.000 | 1.776 |
| Boric Acid | H3BO3 | 0.175 | 0.563 | 1.000 |
Boron (chemical symbol: B) is a rare light metal and the fifth element in the periodic table. The element boron does not exist by itself in nature. Rather, boron combines with oxygen and other elements to form boric acid, or inorganic salts called borates.
Borates are an important mineral group for modern society with demand expected to continue to grow at or above global GDP rates. There are few substitutes for borates especially in high-end applications and agriculture. These markets are expected to grow as global population grows and becomes more affluent.
Schedule of Tenements
| Country | Project | Tenement ID | Tenement Name | Area (km2) | Interest at beginning of quarter | Interest at end of quarter | Note |
| USA | Rhyolite Ridge | NMC1118666 | NLB claims (160) | 13 | 100% | 100% | No change |
| USA | Rhyolite Ridge | NMC1117360 | SLB claims (199) | 16.5 | 100% | 100% | 70 new claims added |
| USA | Rhyolite Ridge | NMC 1129523 | BH claims (81) | 7 | 0% | 0%, option to purchase 100% | No change |
| USA | SM | NMC1166813 | SM claims (96) | 7.7 | 0% | 100% | New claims |
| USA | GD | NMC1166909 | GD claims (13) | 1.1 | 0% | 100% | New claims |
| USA | CLD | NMC1167799 | CLD claims (65) | 5.2 | 0% | 100% | New claims |
| USA | New Morenci | AMC393550 | MP claims (2) | 0.12 | 100% | 100% | No change |
| USA | Tokop | NMC883619 | TK claims (73) | 4.82 | 100% | 100% | No change |
| USA | Tokop | NMC285234 | Path Patents (11) | 0.74 | 0%, option to purchase 100% | 0%, option to purchase 100% | No change |
| USA | Tokop | NMC814692 | Path Unpatented (5) | 0.40 | 0%, option to purchase 100% | 0%, option to purchase 100% | No change |
| USA | Bartlett | NMC938020 | PEARL claims (8) | 0.67 | 0%, option to purchase 100% | 0%, option to purchase 100% | No change |
| USA | Lone Mt | NMC913404 | NAMMCO claims (71) | 5.43 | 0%, earning 100% | 0%, earning 100% | No change |
| USA | Lone Mt | NMC1071591 | LMG claims (37) | 2.80 | 100% | 100% | No change |
| USA | Lone Mt | NMC1094601 | SW claims (24) | 2.0 | 100% | 100% | No change |
| USA | Towers Mt | AMC426407 | CK claims (32) | 2.54 | 100% | 100% | No change |