ioneer Ltd 6-K, filed Apr 26, 2023
ioneer Ltd (IONR)
6-K
2023-04-26
For: 2023-04-26
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Added on
April 05, 2026
About this 6-K
ioneer Ltd filed this 6-K on April 26, 2023.
UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
FORM 6-K
REPORT OF FOREIGN PRIVATE ISSUER PURSUANT TO RULE 13A-16
OR 15D-16 OF THE SECURITIES EXCHANGE ACT OF 1934
For the month of April 2023
Commission File Number: 001-41412
ioneer Ltd
(Translation of registrant’s name into English)
Suite 5.03, Level 5, 140 Arthur Street
North Sydney, NSW 2060, Australia
(Address of principal executive offices)
Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40‑F.
Form 20-F ☒ Form 40-F ☐
Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1): ☐
Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7): ☐
EXHIBIT INDEX
The following exhibits are filed as part of this Form 6-K:
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Exhibit
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Description
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Press Release
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SIGNATURE
Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.
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ioneer Ltd
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(registrant)
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Date: April 26, 2023
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By: |
/s/ Ian Bucknell
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| Name: |
Ian Bucknell
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| Title: |
Chief Financial Officer & Company Secretary
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Exhibit 99.1
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Mineral Resource increases by 168% to 3.4 Mt lithium carbonate
Underscores growth potential for U.S. supply chain
Highlights:
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Rhyolite Ridge South Basin Mineral Resource of 360 Mt containing 3.4 Mt of lithium carbonate equivalent (168% increase) and 14.1 Mt of boric acid equivalent (18% increase) 1.
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The Mineral Resource now includes both high-boron lithium mineralisation and low-boron lithium mineralisation. The previous Mineral Resource estimate only included high-boron lithium mineralisation.
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Demonstrates optionality around future growth opportunities including increasing lithium production with or without increasing boron production.
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The March 2023 Mineral Resource lies entirely within the project boundary currently being permitted under the Mine Plan of Operation.
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All mineralised units remain open in three directions with approximately 60% of the South Basin remaining to be drilled, underscoring the potential for further increases in the Resource.
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Rhyolite Ridge is ideally placed to play a pivotal role in the electrification of transportation in the U.S. In production, it will support the rapidly developing domestic lithium battery supply chain
and lead innovation and sustainability in the production of materials critical to a clean energy future.
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Wednesday, 26 April 2023 – Ioneer Ltd (“Ioneer” or
the “Company”) (ASX: INR, NASDAQ: IONR) is pleased to announce an updated Mineral Resource estimate for the South Basin at the Rhyolite Ridge Lithium-Boron Project located in Nevada, USA. The
effective date for the updated Mineral Resource estimate is March 31, 2023.
WSP USA Inc. (‘WSP’; formerly Golder Associates Inc.) estimated the March 2023 Mineral Resource and provided the previous (2020) Mineral Resource and Ore Reserve estimates for the Rhyolite Ridge
Definitive Feasibility Study (‘DFS’)2 completed in April 2020.
The updated South Basin Mineral Resource estimate comprises:
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Tonnage increase from 146.5 Mt to 360.0 Mt (up 145%)
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Lithium carbonate equivalent (LCE) increase from 1.2 Mt to 3.4 Mt (up 168%)
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Boric acid equivalent (BAE) increase from 11.9 Mt to 14.1 Mt (up 18%)
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Cut-off grades unchanged at 1,090ppm Li and 5,000ppm B
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1 See ASX announcement titled “Rhyolite Ridge Ore Reserve Increased 280% to 60 million tonnes” dated 30 April 2020.
2 See ASX announcement titled “Ioneer delivers Definitive Feasibility Study that confirms Rhyolite Ridge as a world-class lithium and boron project” dated 30
April 2020.
Ioneer Ltd. (ASX: INR, NASDAQ: IONR) Suite 16.01, 213 Miller Street, North Sydney, NSW 2060 T: +61 2 9922
5800 W: Ioneer.com ABN: 76 098 564 606
Approximately 80% of the Mineral Resource is classified as Measured and Indicated. Approximately 44% of the Mineral Resource is classified as high-boron lithium mineralisation (HiB-Li) and 56% as
low-boron lithium mineralisation (LoB-Li).
Background
The Rhyolite Ridge South Basin stratigraphy comprises lake-bed sedimentary rocks of the Cave Spring Formation overlaying volcanic rocks of the Rhyolite Ridge Volcanic unit. The Cave Spring Formation
can reach total thickness in excess of 300 metres and comprises a series of 11 sub-horizontal sedimentary units.
The Cave Spring Formation units are generally laterally continuous over several kilometres across the extent of the South Basin; however, thickness of the units can vary due to both primary
depositional and secondary structural features. The Cave Spring Formation is unconformably overlain by approximately 20 metres of unconsolidated alluvium.
Figure 1. Geological map showing South Basin (green), Mineral Resource area (grey) and location of east-west cross-section (black) shown below in Figure 2.
Figure 2 – Schematic east-west cross-section illustrating Cave Spring Formation and mineralised layers


The key mineralised units of the Cave Spring Formation in the sequence are as follows (illustrated in Fig. 2), from top to bottom:
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M5 - high-grade lithium, low-grade boron, high-clay
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B5 - high-grade lithium, high-grade boron, low-clay
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S5 -moderate-grade lithium, low-grade boron, low-clay
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L6 – moderate grade lithium, high and low-grade boron, low clay
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Lithium mineralisation is present in all four units in the range of 1000-3000ppm. For the purpose of flowsheet design and ore characterisation, Ioneer classifies the lithium mineralisation into
three basic types:
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Type 1: High-boron lithium mineralisation where searlesite is the dominant minerals (B5 and L6)
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Type 2: Low-boron lithium mineralisation where smectite-clay is the dominant mineral (M5)
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Type 3: Low-boron lithium mineralisation where other minerals dominate and searlesite and smectite-clay are very low or absent (S5 and L6)
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The April 2020 Mineral Resource estimate by Golder Associates USA Inc. (now WSP) only included Type 1 HiB-Li mineralisation from the B5 and L6 layers. The HiB-Li mineralisation was constrained by
applying a 5,000 ppm Boron cut-off grade as well as a high-level optimised Mineral Resource pit shell.
Type 1 HiB-Li mineralisation (B5 and L6) was considered the most suitable and exclusively used in the Mineral Resource and Ore Reserve estimate for its superior metallurgical and process flowsheet
properties.
As the ore zones that overlay and underlay the B5 ore zone, specifically the M5, S5 and L6 zones, are also lithium and to a lesser extent boron bearing, there is potential for processing as either
feed material to the current design process stream or as a standalone process stream via a second processing facility.
The March 2023 Mineral Resource estimate has been updated and now includes all four stratigraphic layers to incorporate all previously drilled and assayed HiB-Li and LoB-Li mineralisation.
Updated Mineral Resource
The South Basin Mineral Resource estimate is now 360 million tonnes containing 3.4 million tonnes of lithium carbonate equivalent and 14.1 million
tonnes of boric acid equivalent (5,000ppm B and 1,090ppm Li cut-offs applied for the HiB-Li and LoB-Li mineralization streams respectively).
Summary of March 2023 Mineral Resource Estimate – Rhyolite Ridge South Basin
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Processing
Stream
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Classification
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Total Ore
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Li
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B
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Li2CO3
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H3BO3
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Li2CO3
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H3BO3
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Million MT
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ppm
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ppm
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wt%
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wt%
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kMt
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kMt
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Total Stream 1
(> 5,000 ppm B)
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Measured
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43.8
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1,750
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14,350
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0.9
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8.2
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400
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3,590
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Indicated
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92.2
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1,500
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13,800
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0.8
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7.9
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750
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7,280
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Inferred
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20.8
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1,650
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13,700
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0.9
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7.8
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180
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1,630
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Total Stream
1
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156.8
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1,600
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13,950
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0.8
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8.0
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1,330
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12,500
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Total Stream 2
(> 1,090 ppm Li, no B COG)
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Indicated
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158.5
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1,850
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1,450
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1.0
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0.8
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1,570
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1,330
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Inferred
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44.9
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1,900
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900
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1.0
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0.5
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450
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230
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Total Stream
2
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203.4
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1,850
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1,350
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1.0
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0.8
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2,020
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1,560
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Stream 1 + 2
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Total
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360.2
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1,750
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6,850
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0.9
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3.9
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3,350
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14,060
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The updated March 2023 Mineral Resource estimate was completed by WSP, to JORC Code (2012) standards and replaces the Mineral Resource estimate contained within the April 2020 Mineral Resource and
Ore Reserves estimate.
The Ore Reserves referenced in this report have not been updated from the April 2020 Ore Reserves estimate. The Ore Reserves are based exclusively on HiB-Li mineralisation. The Mineral Resources
are reported inclusive of the Ore Reserves.
The March 2023 Mineral Resource estimate has been constrained by applying a 5,000 ppm Boron cut-off grade to HiB-Li mineralisation within the B5, M5, and L6 geological units as well as a 1,090 ppm
Lithium cut-off grade to LoB-Li mineralisation in the M5, S5 and L6 geological units. Both styles of mineralisation have also been constrained by the application of a single high-level optimised Mineral Resource pit shell.
Relative to the April 2020 Mineral Resource estimate, the updated March 2023 Mineral Resource estimate for the Project reflects a significant increase in the estimated Mineral Resource tonnes,
including the reporting of the Mineral Resources for the LoB-Li mineralisation for the first time for the Project. The updated Mineral Resource estimate also presents a small increase to the HiB-Li Mineral Resource tonnes as the impact of the
LoB-Li mineralisation resulted in a net expansion of the constraining Mineral Resource pit shell.
As all four mineralised layers are tabular and stacked vertically, the increased Mineral Resource sits entirely within the same 3 square kilometre (km2) area as the April 2020 Mineral Resource estimate and represents only 38% of the 8km2 South Basin total prospective
area (as illustrated in Fig. 1). Additionally, all four mineralised layers remain open to the North, South and East providing significant further Resource growth potential with extension drilling, initially to the south, to be pursued immediately
upon receipt of final permitting.
In December 2022, the United States Fish and Wildlife Service (USFWS) listed Tiehm’s buckwheat as an endangered species under the Endangered Species Act (ESA) and has designated critical habitat by
way of applying a 500 m radius around several distinct plant populations that occur on the Project site. Ioneer is committed to the protection and conservation of the Tiehm’s buckwheat. The Project’s Mine Plan of Operations submitted to the BLM
in July 2022 and currently under NEPA review has no direct impact on Tiehm’s buckwheat and includes measures to minimise and mitigate for indirect impacts within the designated critical habitat areas identified.
The mineral resource pit shell used to constrain the March 31, 2023, Mineral Resource estimate was not adjusted to account for any impacts from avoidance of Tiehm’s buckwheat or minimisation of
disturbance within the designated critical habitat. Estimates run inside the buckwheat avoidance areas identified 29.4 Mt at 1,650 ppm Li and 9,000 ppm B (both HiB-Li and LoB-Li streams combined), reflecting approximately 8% of the March 2023
global Mineral Resource estimate for the Project. The tonnes and grade within the avoidance polygons have not been removed from the Mineral Resources for the March 2023 estimate. Environmental and permitting assumptions and factors will be taken
into consideration during future modifying factors studies for the Project. These permitting assumptions and factors may result in potential changes to the Mineral Resource footprint in the future.
Further detailed information is provided in:
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Appendix A - Mineral Resource Statement and Parameters
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Appendix B – Figures
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Appendix C – JORC Table 1
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James Calaway, Executive Chairman of Ioneer commented:
“We are extremely pleased with the significant increase in the South Basin Mineral Resource estimate. It highlights Rhyolite Ridge’s
optionality and multi-generational scale potential to provide a secure, sustainable, and reliable domestic source of lithium for the growing electric vehicle battery supply chain.”
Bernard Rowe, Managing Director of Ioneer commented:
“To date, we have focussed heavily on progressing our development plan for Rhyolite Ridge. With binding offtakes in place, debt &
equity commitments of nearly US$1.2 billion and the project in the final stage of permitting, we can now begin demonstrating the broader scale potential at Rhyolite Ridge. The updated Mineral Resource base for the South Basin is a fantastic start
and we look forward to building on this further with significant growth potential through South Basin extensions as well as increased exploration efforts on the mineralised and much larger North Basin.”
This ASX release has been authorised by Ioneer Managing Director Bernard Rowe.
-- ENDS --
Contacts:
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Chad Yeftich
Ioneer USA Corporation
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Jason Mack
Ioneer Limited
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Investor Relations (USA)
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Investor Relations (AUS)
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T: +1 775 993 8509
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T: +61 410 611 709
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E: ir@Ioneer.com
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E: jmack@Ioneer.com
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Resource Estimate Advisers
Ioneer engaged the independent services of Golder Associates USA Inc. (now WSP) to compile and complete the updated South Basin Mineral Resource estimate, which has been
verified and approved by their appointed Competent Person in compliance with JORC Code (2012).
Competent Persons Statement
The information in this report that relates to the March 2023 Mineral Resource estimate is based on information compiled by Jerry DeWolfe, a Competent Person who is a
Professional Geologist (P.Geo.) with the Association of Professional Engineers and Geoscientists of Alberta (APEGA), a “Recognized Professional Organisation” included in a list promulgated by ASX from time to time. Mr DeWolfe is a full-time
employee of WSP Canada Inc. (WSP, formerly Golder) and is independent of Ioneer and its affiliates. Mr DeWolfe 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’ (JORC Code 2012). Mr DeWolfe consents to the inclusion in the
report of the matters based on his information in the form and context in which it appears.
The information in this report that relates to the 2020 Ore Reserve estimate is based on information compiled by Terry Kremmel, a Competent Person who is a
certified Professional Engineer (‘PE’) in the US and a Registered Member of the Society for Mining, Metallurgy, & Exploration (‘SME’), a “Recognized Professional Organisation” included in a list promulgated by ASX from time to time.
Mr Kremmel is a full-time employee of WSP USA Inc. (WSP, formerly Golder) and is independent of Ioneer and its affiliates. Mr Kremmel 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’ (JORC Code 2012). Mr Kremmel
consents to the inclusion in the report of the matters based on his information in the form and context in which it appears.
About Ioneer
Ioneer Ltd is the 100% owner of the Rhyolite Ridge Lithium-Boron Project located in Nevada, USA, the only known lithium-boron deposit in North America and one of only two known such deposits in the world. The
Definitive Feasibility Study (DFS) completed in 2020 confirmed Rhyolite Ridge as a world-class lithium and boron project that is expected to become a globally significant, long-life, low-cost source of lithium and boron vital to a sustainable
future. In September 2021, Ioneer entered into an agreement with Sibanye-Stillwater where, following the satisfaction of conditions precedent, Sibanye-Stillwater will acquire a 50% interest in the Project, with Ioneer maintaining a 50% interest
and retaining the operational management responsibility for the joint venture. In January 2023, Ioneer received a conditional commitment from the U.S. Department of Energy Loan Programs Office for up to $700 million of debt financing. Ioneer
signed separate offtake agreements with Ford Motor Company and PPES (joint venture between Toyota and Panasonic) in 2022 and Korea’s EcoPro Innovation in 2021.
Important notice and disclaimer
Forward-looking statements
This announcement contains certain forward-looking statements and comments about future events, including Ioneer’s expectations about the Project and the performance of its businesses. Forward looking statements
can generally be identified by the use of forward-looking words such as ‘expect’, ‘anticipate’, ‘likely’, ‘intend’, ‘should’, ‘could’, ‘may’, ‘predict’, ‘plan’, ‘propose’, ‘will’, ‘believe’, ‘forecast’, ‘estimate’, ‘target’ and other similar
expressions within the meaning of securities laws of applicable jurisdictions. Indications of, and guidance on, the Conditional Commitment, financing plans, future earnings or financial position or performance are also forward-looking statements.
Forward-looking statements involve inherent risks and uncertainties, both general and specific, and there is a risk that such predictions, forecasts, projections and other forward-looking statements will not be
achieved. Forward-looking statements are provided as a general guide only and should not be relied on as an indication or guarantee of future performance. Forward looking statements involve known and unknown risks, uncertainty and other factors
which can cause Ioneer’s actual results to differ materially from the plans, objectives, expectations, estimates, and intentions expressed in such forward-looking statements and many of these factors are outside the control of Ioneer. Such risks
include, among others, uncertainties related to the finalisation, execution, and funding of the DOE financing, including our ability to successfully negotiate definitive agreements and to satisfy any funding conditions, as well as other
uncertainties and risk factors set out in filings made from time to time with the U.S. Securities and Exchange Commission and the Australian Securities Exchange. As such, undue reliance should not be placed on any forward-looking statement. Past
performance is not necessarily a guide to future performance and no representation or warranty is made by any person as to the likelihood of achievement or reasonableness of any forward-looking statements, forecast financial information or other
forecast. Nothing contained in this announcement, nor any information made available to you is, or shall be relied upon as, a promise, representation, warranty or guarantee as to the past, present or the future performance of Ioneer.
Except as required by law or the ASX Listing Rules, Ioneer assumes no obligation to provide any additional or updated information or to update any forward-looking statements, whether as a result of new information,
future events or results, or otherwise.

Appendix A
Mineral Resource Statement and Parameters
A summary of the March 2023 Mineral Resource estimate is provided in the table below. Note that Mineral Resources are reported inclusive of the Ore Reserve described in Appendix B.
March 2023 Mineral Resource Estimate for Rhyolite Ridge South Basin

Notes:
1. mt = million tonnes; Li = lithium; B = boron; ppm = parts per million; Li2CO3 = lithium carbonate; H3BO3 =
boric acid; kt = thousand tonnes.
ioneer Ltd. (ASX: INR) Suite 5.03, 140 Arthur Street, North Sydney, NSW 2060 T: +61 2 9922 5800 W: ioneer.com ABN: 76 098 564 606
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2. Totals may differ due to rounding, Mineral Resources reported on a dry in-situ basis. Lithium is converted to Equivalent Contained Tonnes of Lithium Carbonate (Li2CO3) using a stochiometric conversion factor of 5.322, and boron is converted to Equivalent Contained Tonnes
of Boric Acid (H3BO3) using a stochiometric conversion factor of 5.718.
Equivalent stochiometric conversion factors are derived from the molecular weights of the individual elements which make up Lithium Carbonate (Li2CO3) and Boric Acid (H3BO3).
3. The statement of estimates of Mineral Resources has been compiled by Mr. Jerry DeWolfe, who is a full-time employee of WSP Canada Inc. (WSP; formerly Golder) and a Professional Geologist (‘P.Geo’.)
with the Association of Professional Engineers and Geoscientists of Alberta (‘APEGA’), a “Recognized Professional Organization” included in a list promulgated by the ASX from time to time. Mr. DeWolfe has sufficient experience that is
relevant to the style of mineralisation and type of deposit under consideration and to the activity that he has undertaken to qualify as a Competent Person as defined in the JORC Code (2012).
4. All Mineral Resource figures reported in the table above represent estimates at March 31, 2023. Mineral Resource estimates are not precise calculations, being dependent on the interpretation of limited
information on the location, shape and continuity of the occurrence and on the available sampling results. The totals contained in the above table have been rounded to reflect the relative uncertainty of the estimate.
5. Mineral Resources are reported in accordance with the Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves (The Joint Ore Reserves Committee Code – JORC 2012
Edition).
6. The Mineral Resource estimate is the result of determining the mineralized material that has a reasonable prospect of economic extraction. In making this determination, constraints were applied to the
geological model based upon a pit optimization analysis that defined a conceptual pit shell limit. The conceptual pit shell was based upon a 5,000ppm boron cut-off grade for HiB-Li mineralisation and 1,090ppm lithium cut-off grade for
LoB-Li mineralization below 5,000ppm boron. The pit shell was constrained by a conceptual Mineral Resource optimized pit shell for the purpose of establishing reasonable prospects of eventual economic extraction based on potential
mining, metallurgical and processing grade parameters identified by mining, metallurgical and processing studies performed to date on the Project. Key inputs in developing the Mineral Resource pit shell included a 5,000ppm boron
cut-off grade for HiB-Li mineralisation and 1,090ppm lithium cut-off grade for LoB-Li mineralization; mining cost of US$2.67/tonne plus $0.0059/tonne-vertical metre of haulage; plant feed processing and grade control costs of
US$45.45/tonne of plant feed; boron and lithium recovery of 83.5% and 81.8%, respectively; boric acid sales price of US$700/tonne; lithium carbonate sales price of US$10,000/tonne; and sales/transport costs of US$160/tonne of product.
In December 2022, the United States Fish and Wildlife Service (USFWS) listed Tiehm’s buckwheat as an endangered species under the Endangered Species Act (ESA) and has designated critical habitat by way of applying a 500 m radius
around several distinct plant populations that occur on the Project site. ioneer is committed to the protection and conservation of the Tiehm’s buckwheat. The Project’s Mine Plan of Operations submitted to the BLM in July 2022 and
currently under NEPA review has no direct impact on Tiehm’s buckwheat and includes measures to minimise and mitigate for indirect impacts within the designated critical habitat areas identified.
The mineral resource pit shell used to constrain the March 31, 2023, mineral resource estimate was not adjusted to account for any impacts from avoidance of Tiehm’s buckwheat or minimisation of disturbance within the designated
critical habitat. Estimates run inside the avoidance polygons identified 29.4 Mt at 1,650 ppm Li and 9,000 ppm B (both HiB-Li and LoB-Li streams combined), reflecting approximately 8% of the March 2023 global Mineral Resource estimate
for the Project. The tonnes and grade within the avoidance polygons have not been removed from the Mineral Resources for the March 2023 estimate. Environmental and permitting assumptions and factors will be taken into consideration
during future modifying factors studies for the Project. These permitting assumptions and factors may result in potential changes to the Mineral Resource footprint in the future.
Comparison with Previous Resource
The Table below presents a summary comparison of the current March 31, 2023 Mineral Resource estimate against the previous Mineral Resource estimate for the Project, prepared by Golder (now WSP) in April 2020 in association with
the 2020 DFS.

The updated March 31, 2023 Mineral Resource estimate has been constrained by applying a 5,000 ppm Boron cut-off grade to HiB-Li mineralisation within the B5, M5, and L6 geological units as well as a 1,090 ppm Lithium cut-off grade
to LoB-Li mineralisation in the M5, S5 and L6 geological units. Both styles of mineralisation have also been constrained by the application of a single high-level optimised resource pit shell.
Relative to the April 2020 Mineral Resource estimate, the updated March 2023 Mineral Resource estimate for the Project reflects a significant increase in the estimated resource tonnes, including the reporting of the Mineral
Resources for the LoB-Li mineralisation for the first time for the Project.
The updated Mineral Resource estimate also presents a small increase to the HiB-Li Mineral Resource tonnes as the impact of the LoB-Li mineralisation resulted in a net expansion of the constraining Mineral Resource pit shell.
As all four mineralised layers are tabular and stacked vertically, the increased Mineral Resource sits entirely within the same 3 square kilometre (km2)
area as the April 2020 Mineral Resource estimate.
Summary of Resource Estimate Parameters and Reporting Criteria
In accordance with ASX Listing Rules and the JORC Code (2012 Edition), a summary of the material information used to estimate the Mineral Resource is summarised below (for further information please refer to Table 1 in Appendix D).
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The Rhyolite Ridge Mineral Resource area extends over a north-south strike length of 2,450m (from 4,184,000 mN – 4,186,450 mN), has a maximum width of 1,250m (424,150 mE – 425,400 mE) and includes the 420m vertical interval
from 1,920mRL to 1,500 mRL.
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The Rhyolite Ridge Project tenements (unpatented mining claims) are owned by ioneer Minerals Corporation, a company wholly owned by ioneer Ltd. The unpatented mining claims are located on US federal land administered by the
Bureau of Land Management (BLM).
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Geology and Geological Interpretation
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Lithium and boron mineralisation is stratiform in nature and is hosted within Tertiary-age carbonate-rich sedimentary rock, deposited in a lacustrine environment in the Basin and Range terrain of Nevada, USA.
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Drilling Techniques and Hole Spacing
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Drill holes used in the Mineral Resource estimate included 42 reverse circulation (RC) holes and 65 core holes for a total of 8,952m within the defined mineralisation. The full
database for the South Basin contains records for 109 drill holes for 24,300m of drilling.
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Drill hole spacing is 100m by 100m (or less) over most of the deposit. Spacing increases to approximately 200m by 300m along the eastern margin of the deposit.
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Drill holes were logged for a combination of geological and geotechnical attributes. The core has been photographed and measured for RQD and core recovery.
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Sampling and Sub-Sampling Techniques
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Drilling was conducted by American Lithium Minerals Inc., the previous owner of the property between 2010 and 2011 and by ioneer in 2017 to 2019. For RC drilling, a 12.7-centimetre (cm)
hammer was used with sampling conducted on 1.52m intervals and split using a rig mounted rotary splitter. The hammer was replaced with a tri-cone bit in instances of high groundwater flow. For diamond core, HQ core size
diameter with standard tube was used. Core recoveries of 97% were achieved by ioneer at the project. The core was sampled as half core at 1.52m intervals using a standard electric core saw.
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Sampling Analysis Method
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Samples were submitted to ALS Minerals Laboratory in Reno, Nevada for sample preparation and analysis. The entire sample was oven dried at 105˚ and crushed to -2 millimetre (mm). A
sub-sample of the crushed material was then pulverised to better than 85% passing -75 microns (µm) using a LM5 pulveriser. The pulverised sample was split with multiple feed in a Jones
riffle splitter until a 100-200 gram (g) sub-sample was obtained for analysis.
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Analysis of the samples was conducted using aqua regia 2-acid and 4-acid digest for ICP-MS on a multi-element suite. This method is appropriate for understanding sedimentary lithium deposits and is a total method.
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Standards for lithium, boron, strontium and arsenic and blanks were routinely inserted into sample batches and acceptable levels of accuracy were reportedly obtained. Based on an evaluation of the quality assurance and
quality control (QA/QC) results all assay data has been deemed by the WSP Competent Person as suitable and fit for purpose in Mineral Resource estimation.
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Cut-off Grades
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The Mineral Resource estimate presented in this Report has been constrained by the application of an optimized Mineral Resource pit shell. The Mineral Resource pit shell was developed using Maptek Vulcan Mine Planning
software.
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The Mineral Resource estimate assumes the use of two processing streams: one which can process ore with boron content greater than 5,000 ppm and one which can process ore with boron content less than 5,000 ppm.
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The Mineral Resource estimate has been constrained by applying a 5,000 ppm Boron cut-off grade to HiB-Li mineralisation within the B5, M5, and L6 geological units as well as a 1,090 ppm Lithium cut-off grade to LoB-Li
mineralisation in the M5, S5 and L6 geological units.
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•
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Key input parameters and assumptions for the Mineral Resource pit shell included the following:
|
| o |
B cut-off grade of 5,000 ppm for HiB-Li processing stream and no B cut-off grade for LoB-Li processing stream
|
| o |
No Li cut-off grade for HiB-Li processing stream and Li cut-off grade of 1,090 ppm for LoB-Li processing stream
|
| o |
Overall pit slope angle of 35 degrees in the alluvium and 42 degrees in other rock units (wall angle guidance provided by EnviroMINE, Inc., who developed the geotechnical design).
|
| o |
Mining cost of US$2.67/tonne (t) plus US$0.0059/t-vertical foot of haulage.
|
| o |
Ore processing and grade control costs of US$45.45/t of ore for HiB-Li Processing Stream and US$40.69/t of ore for LoB-Li Processing Stream.
|
| o |
Boron and Li recovery of 83.5% and 81.8% respectively for HiB-Li Processing Stream.
|
| o |
Boron Recovery for LoB-Li Processing Stream variable by lithology as follows: 72% in M5 Unit, 79.5% in B5 unit, 75% in S5 unit, and 81% in L6 unit.
|
| o |
Lithium Recovery for LoB-Li Processing Stream variable by lithology as follows: 76% in M5 unit, 85% in B5 unit, 85% in S5 unit, and 86% in L6 unit.
|
| o |
Boric Acid sales price of US$700/t.
|
| o |
Lithium Carbonate sales price of US$10,000/t.
|
| o |
Sales/Transport costs of US$160/t of product.
|
Estimation Methodology
| • |
Drill core samples were composited to 1.52m composite lengths prior to interpolation of grade data into the block model. Composite lengths honoured geological contacts (i.e. composites did not span unit contacts). The
composite length was selected based on the median sample length from the drill hole assay database.
|
| • |
Based on a statistical analysis, extreme B grade values were identified in some of the units other than the targeted B5, M5 and L6 units. As a result, restricted interpolation was applied to B grades in units other than the
B5, M5 and L6.
|
| • |
The geological model was developed as a gridded surface stratigraphic model and a stratigraphically constrained grade block model using MineScape (v6.1.1) StratModel and BlockModel, which are computer-assisted geological,
grade modelling, and estimation software applications.
|
| • |
Domaining in the model was constrained by the roof and floor surfaces of the geological units. The unit boundaries were modelled as hard boundaries, with samples interpolated only within the unit in which they occurred.
|
| • |
The geological model used as the basis for estimating Mineral Resources was developed as a stratigraphic gridded surface model using a 7.6m regularized grid. The grade block model was developed using a 15.2m north-south by
15.2m east-west by 1.52m vertical parent block dimension with maximum sub-celling dimensions of 3.8m by 3.8m by 0.4m. The grid cell and block size dimensions represent 25 percent of the nominal drill hole spacing across the
model area.
|
| • |
Inverse Distance Squared (‘ID2’) grade interpolation was used for the estimate, constrained by stratigraphic unit roof and floor surfaces from
the geological model. Up to four passes were used to estimate the blocks in the model and more than 99% of blocks were filled in the first two passes.
|
| • |
The density values used to convert volumes to tonnages were assigned on a by-geological unit basis using mean values calculated from 249 density samples collected from drill core during the 2010-2011 and drilling programs.
The density values ranged from 1.80 grams per cubic centimetre (‘g/cm3’) to 2.11g/cm3. The density analyses were performed using the Archimedes-principle (water displacement) method for density determination, with values reported in dry basis.
|
Classification Criteria
| • |
Estimated Mineral Resources were classified as follows:
|
| o |
Measured: 152.5m spacing between points of observation, with sample interpolation from a minimum of two drill holes.
|
| o |
Indicated: 305m spacing between points of observation, with sample interpolation from a minimum of two drill holes.
|
| o |
Inferred: 610m spacing between points of observation, with sample interpolation from a minimum of two drill holes.
|
| • |
The Mineral Resource classification has included the consideration of data reliability, spatial distribution and abundance of data and continuity of geology and grade parameters.
|
Mining and Metallurgical Methods and Parameters
| • |
The Mineral Resource estimate presented in this Report was developed with the assumption that the HiB-Li mineralization within the Mineral Resource pit shell has a reasonable prospect for eventual economic extraction using
current conventional open pit mining methods.
|
| • |
The basis of the mining assumptions made in establishing the reasonable prospects for eventual economic extraction of the HiB-Li mineralization are based on preliminary results from mine design and planning work that is
in-progress as part of an ongoing Feasibility Study for the Project.
|
| • |
The basis of the metallurgical assumptions made in establishing the reasonable prospects for eventual economic extraction of the HiB-Li mineralization are based on results from metallurgical and material processing work
that was developed as part of the ongoing Feasibility Study for the Project. This test work was performed using current processing and recovery methods for producing Boric acid and Lithium carbonate products.
|
A second process stream to recover Li from low boron mineralized (LoB-Li) units is being developed. Current results indicate a reasonable process and expectation for economic extraction of the LoB-Li from the S5, M5 and L6 units.
This test work was performed using current processing and recovery methods for producing Boric acid and Lithium carbonate products.
|
APPENDIX A: JORC Code, 2012 Edition - Table 1
|
The following table provides a summary of important assessment and reporting criteria used at the ioneer Ltd. Rhyolite Ridge Project (the Project) for the reporting of exploration results and Lithium-Boron Mineral
Resources and Ore Reserves in accordance with the Table 1 checklist in The Australasian Code for the Reporting of Exploration Results, Mineral Resources and Ore Reserves (The JORC Code, 2012 Edition). Table 1 is a checklist or reference for use by
those preparing Public Reports on Exploration Results, Mineral Resources, and Ore Reserves.
JORC TABLE 1
SECTION 1 SAMPLING TECHNIQUES AND DATA
(Criteria listed in this section apply to all succeeding sections.)
|
Criteria
|
JORC Code 2012 Explanation
|
Commentary
|
||||||
|
Sampling Techniques
|
• Nature and quality of sampling (e.g. cut channels, random chips, or specific specialised industry standard measurement tools appropriate to the minerals
under investigation, such as down hole gamma sondes, or handheld XRF instruments, etc.). These examples should not be taken as limiting the broad meaning of sampling
|
• The nature and quality of the sampling from the various sampling programs includes the following:
• Reverse circulation (RC) Drilling: a sample was collected every 1.52 metre (m) from a 127-millimetre (mm) diameter drill hole and split using a
rig-mounted rotary splitter. Samples, with a mean weight of 4.8 kilograms (kg) were submitted to ALS Minerals laboratory in Reno, NV where they were processed for assay. RC samples represent 55% of the
total intervals sampled to date.
• Core Drilling: Core samples were collected from HQ (63.5 mm core diameter) and PQ (85.0 mm core diameter) drill core, on a mean interval of 1.52 m, and cut using a water-cooled diamond blade
core saw. Samples, with a mean weight of 1.8 kg, were submitted to ALS where they were proceeded for assay.
• Drill Hole Deviation: Inclined core drill holes were surveyed to obtain downhole deviation by the survey company (Minex Surveying) or drilling company (Idea Drilling) with a downhole Reflex
Mems Gyros tool, for all but three of the drill holes. One drill hole could not be surveyed due to tool error (SBH-72), and two were intentionally surveyed using an Acoustic Televiewer (SBH-60, SBH-79).
• Trenches: In addition to sampling from drill holes, samples were collected from 19 mechanically excavated trenches in 2010. The trenches were excavated from the outcrop/subcrop using a
backhoe and or hand tools. Chip samples were then collected from the floor of the trench. Due to concerns with correlation and reliability of the results from the trenches, The Competent Person has not included any of this data in the
geological model or Mineral Resource estimate.
|
|
APPENDIX D: JORC Code, 2012 Edition - Table 1
|
|
Criteria
|
JORC Code 2012 Explanation
|
Commentary
|
||||||
|
• Include reference to measures taken to ensure sample representivity and the appropriate calibration of any measurement tools or systems used.
|
• Measures taken to ensure sample representivity include the following:
• Due to the nature of RC samples, lithological boundaries are not easily honoured; therefore, continuous 1.52 m sample intervals were taken to ensure as representative a sample as possible.
Lithological boundaries were adjusted as needed by the senior ioneer geologist once the assay results were received.
• Core sample intervals were selected to reflect visually identifiable lithological boundaries wherever possible, to ensure sample representivity. In cases where the lithological boundaries
were gradational, the best possible interval was chosen.
• All chip and core sampling were completed by or supervised by a senior ioneer geologist. The senior ioneer and Newfields geologists referenced here, and throughout this Table 1, have
sufficient relevant experience for the exploration methods employed, the type of mineralization being evaluated, and are registered professional geologists in their jurisdiction; however, they are not Competent Persons according to the
definition presented in JORC as they are not members of one of the Recognized Professional Organization” included in the ASX list referenced by JORC.
• The Competent Person was not directly involved during the exploration drilling programs and except for observing sampling procedures on two drill holes during the site visit, was not present
to observe sample selection. Based on review of the procedures during the site visit and subsequent review of the data, it is the opinion of the Competent Person that the measures taken to ensure sample representivity were reasonable for the
purpose of estimating Mineral Resources.
|
|
APPENDIX D: JORC Code, 2012 Edition - Table 1
|
| Criteria |
JORC Code 2012 Explanation
|
Commentary
|
||||||
| |
• Aspects of the determination of mineralisation that are Material to the Public Report. In cases where ‘industry standard’ work has been done this would be
relatively simple (eg ‘reverse circulation drilling was used to obtain 1 m samples from which 3 kg was pulverised to produce a 30 g charge for fire assay’). In other cases more explanation may be required, such as where there is coarse gold
that has inherent sampling problems. Unusual commodities or mineralisation types (e.g. submarine nodules) may warrant disclosure of detailed information
|
• Aspects of the determination of mineralization included visual identification of mineralized intervals by a senior ioneer geologist using lithological characteristics including clay and
carbonate content, grain size and the presence of key minerals such as Ulexite (hydrated sodium calcium borate hydroxide) and Searlesite (sodium borosilicate). A visual distinction between some units, particularly where geological contacts
were gradational was initially made. Final unit contacts were then determined by a senior ioneer geologist once assay data were available.
• The Competent Person was not directly involved during the exploration drilling programs; however, the visual identification of mineralized zones and the process for updating unit and
mineralized contacts was reviewed with the ioneer senior geologist during the site visit. The Competent Person evaluated the identified mineralized intervals against the analytical results and agrees with the methodology used by ioneer to
determine material mineralization.
|
||||||
|
Drilling techniques
|
• Drill type (e.g. core, reverse circulation, open-hole hammer, rotary air blast, auger, Bangka, sonic, etc..) and details (e.g. core diameter, triple or
standard tube, depth of diamond tails, face-sampling bit or other type, whether core is oriented and if so, by what method, etc.).
|
• Both RC and core drilling techniques have been used on the Project. Exploration drilling programs targeting Lithium-Boron (Li-B) mineralization on the Project have been implemented by American Lithium Minerals Inc. (2010-2012) and ioneer (formerly Global Geoscience) in 2016, 2017, 2018 and 2019.
• Prior to 2018, all RC drilling was conducted using a 127 mm hammer. All pre-2018 core drill holes were drilled using HQ sized core with a double-tube
core barrel.
• For the 2018-2019 drilling program, all core holes (vertical and inclined) were RC drilled through unconsolidated alluvium, then cored through to the end of the drill hole. All but two of the
41 core holes were drilled as PQ sized core, with the remaining two as HQ sized core. Drilling was completed using a triple-tube core barrel (split inner tube) which was preferred to a double-tube core barrel (solid inner tube) as the
triple-tube improved core recovery and core integrity during core removal from the core barrel.
|
|
APPENDIX D: JORC Code, 2012 Edition - Table 1
|
| Criteria |
JORC Code 2012 Explanation
|
Commentary
|
||||||
|
Drill sample recovery
|
• Method of recording and assessing core and chip sample recoveries and results assessed.
|
• Prior to 2017, chip recovery was not recorded for the RC drilling therefore the Competent Person cannot comment on drill sample recovery for this period of drilling.
• For the 2017 RC drilling program, the drill holes were geologically logged as they were being drilled; however, no estimates of chip recoveries were
recorded. Therefore, the Competent Person cannot comment on drill sample recovery for this period of drilling.
• For the 2010-2012 and 2016 core drilling programs, both core recovery and rock quality index (RQD) were
recorded for each cored interval. Core recovery was determined by measuring the recovered linear core length and then calculating the recovered percentage against the total length of the core run from the drill advance. The core recovery for
all the drilling ranged from 0% to 100%, with over 65 % of the drill holes having greater than 80% mean core recovery. The core recovery values were recorded by the logging geologist and reviewed by the senior ioneer geologist. The majority
of the 2010-2012 and 2016 core drill holes reported greater than 95% recovery in the B5, M5 and L6 mineralized intervals.
• For the 2018-2019 drilling program, both core recovery and RQD were recorded for each cored interval. Core recovery was determined by measuring the recovered linear core length and then
calculating the recovered percentage against the total length of the core run from the drill advance. The core recovery for all the drilling ranged from 41% to 100%, with over 65% of the drill holes having greater than 90% mean core recovery.
The core recovery values were recorded by the logging geologist and reviewed by the senior ioneer geologist. In the target mineralized intervals (M5, B5 & L6), the mean core recovery was 86% in the B5, 87% in the M5 and 95% in the L6
units, with most of the drill holes reporting greater than 90% recovery in the mineralized intervals.
• The Competent Person considers the core recovery for the 2018-2019, 2016 and 2010-2012 core drilling programs to be acceptable based on statistical analysis which identified no grade bias
between sample intervals with high versus low core recoveries. On this basis, the Competent Person has made the reasonable assumption that the sample results are reliable for use in estimating Mineral Resources.
|
|
APPENDIX D: JORC Code, 2012 Edition - Table 1
|
| Criteria |
JORC Code 2012 Explanation
|
Commentary | ||||||
| |
• Measures taken to maximise sample recovery and ensure representative nature of the samples.
|
• Chip recoveries were not recorded for the 2010-2012 and 2017 RC drilling programs, and there is no indication of measures taken to maximize sample recovery and ensure representative nature of
samples.
• No specific measures for maximizing sample recovery were documented for the 2010-2012 and 2016 core drilling programs.
• During the 2018-2019 drilling program ioneer implemented the use of a triple-tube core barrel to maximize sample recovery and ensure representative nature of samples. A triple-tube core
barrel generally provides improved core recovery over double-tube core barrels, resulting in more complete and representative intercepts for core logging, sampling and geotechnical evaluation. It also limited any potential sample bias due to
preferential loss/gain of material.
|
||||||
|
• Whether a relationship exists between sample recovery and grade and whether sample bias may have occurred due to preferential loss/gain of fine/coarse
material.
|
• Chip recovery was not recorded for the 2010-2012 and 2017 RC drilling program and, therefore, there is no basis for evaluating the relationship between grade and sample recovery for samples
from these programs.
• Based on the Competent Person’s review of the 2010-2012, 2016 and 2018-2019 drilling recovery and grade data there was no observable relationship between sample recovery and grade.
|
|||||||
|
Logging
|
• Whether core and chip samples have been geologically and geotechnically logged to a level of detail to support appropriate Mineral Resource estimation,
mining studies and metallurgical studies.
|
• All core and chip samples have been geologically logged to a level of detail to support appropriate Mineral Resource estimation, such that there are lithological intervals for each drill
hole, with a correlatable geological/lithological unit assigned to each interval.
• The 2018-2019 drilling was also geotechnically logged to a level of detail to support appropriate Mineral Resource estimation.
• The Competent Person has reviewed all unit boundaries in conjunction with the ioneer senior geologist, and where applicable, adjustments have been made by the Competent Person to the
mineralized units based on the assay results intervals to limit geological dilution.
|
||||||
|
• Whether logging is qualitative or quantitative in nature.
|
• The RC and core logging were both qualitative (geological/lithological descriptions and observations) and quantitative (unit lengths, angles of contacts and structural features and fabrics).
|
|||||||
|
• Core (or costean, channel, etc.) photography.
|
• Core photography was completed on every core drill hole for the 2010-2012, 2016 and 2018-2019 core drilling programs.
• All chip trays from the RC holes were also photographed during the various RC drilling programs.
|
|
APPENDIX D: JORC Code, 2012 Edition - Table 1
|
| Criteria |
JORC Code 2012 Explanation
|
Commentary | ||||||
|
• The total length and percentage of the relevant intersections logged.
|
• Prior to 2018, a total length of 8,900 m of RC drilling and 6,000 m of core drilling was completed for the Project, 100% of which was geologically logged by a logging geologist and reviewed
by the senior ioneer geologist.
• For the 2018-2019 drilling, a total length of 300 m of RC drilling and 8,800 m of core drilling was completed for the Project, 100% of which was geologically logged by a logging geologist and
reviewed by the senior ioneer geologist
• For the 2018-2019 drilling, 86% of the 8,800 m of core was geotechnically logged by an engineering geologist/ geotechnical engineer and reviewed by the senior ioneer geologist. The Competent
Person reviewed the geological core logging and sample selection for two complete drill holes.
|
|||||||
|
Sub-sampling techniques and sample preparation
|
• If core, whether cut or sawn and whether quarter, half or all core taken.
|
• The following sub-sampling techniques and sample selection procedures apply to drill core samples:
• During the 2010-2012 and 2016 program, core samples were collected on a mean 1.52 m down hole interval and cut in two halves using a manual core splitter. The entire sample was submitted
for analysis with no sub-sampling prior to submittal.
• During the 2018-2019 drilling program, core samples were collected for every 1.52 m down hole interval and cut using a water-cooled diamond blade core saw utilizing the following
methodology for the two target units. For the M5 unit, ½ core samples were submitted for assay, while the remaining ½ core was retained for reference. For the B5 unit, ¼ core samples were submitted for assay, while ¼ was reserved for future
metallurgical test work and ½ core was retained for reference.
|
||||||
|
• If non-core, whether riffled, tube sampled, rotary split, etc. and whether sampled wet or dry.
|
• The following sub-sampling techniques and sample selection procedures apply to RC Chip Samples:
• Pre-2017 RC chips samples were collected using a wet rotary splitter approximately every 1.52 m depth interval. Two samples were collected for every interval (one main sample and one
duplicate). Only the main sample was submitted for analysis.
• 2017 RC chip samples were collected using a wet rotary splitter attached to a cyclone. One, approximately 10 kg, sample was collected every 1.52 m depth interval. All samples were submitted
for analysis.
|
|
APPENDIX D: JORC Code, 2012 Edition - Table 1
|
| Criteria |
JORC Code 2012 Explanation
|
Commentary | ||||||
|
• For all sample types, the nature, quality and appropriateness of the sample preparation technique.
|
• The Competent Person considers the nature, type and quality of the sample preparation techniques to be appropriate based on the general homogeneous nature of the mineralized zones and the
drilling methods employed to obtain each sample (i.e., RC and core).
|
|||||||
|
• Quality control procedures adopted for all sub-sampling stages to maximise representivity of samples.
|
• Quality control procedures adopted for sub-sampling to maximize representivity include the following:
• During 2016-2017 and 2018-2019 drilling programs, field duplicate/replicate samples were obtained. For the 2017 RC drilling, a duplicate sample was collected every 20th sample.
For the 2016 and 2018-2019 core drilling programs two ¼ core samples were taken at the same time and were analysed in sequence by the laboratory to assess the representivity.
• Twin drill holes at the same site were drilled during the 2010-2012 drilling program. The twin drill hole pairing comprises one RC drill hole (SBH-04) and one core drill hole (SBHC-01). The
Competent Person recommends twinning additional drill hole pairs as part of any future pre-production or infill drilling programs to allow for a more robust review of sample representivity.
• The Competent Person reviewed the results of the duplicate/replicate sampling and twin drill holes. For the duplicate/replicate samples, the R2 value is 0.99, which is very
good. Visual observation of the lithological intervals and the assays for the twin drill holes show that they are very similar, despite the difference in drilling techniques.
|
|||||||
|
• Measures taken to ensure that the sampling is representative of the in situ material collected, including for instance results for field
duplicate/second-half sampling.
|
• The Competent Person considers the samples to be representative of the in-situ material as they conform to lithological boundaries determined during core logging. A review of the primary and
duplicate sample analyses indicates a high degree of agreement between the two sample sets (R2 value of 0.99).
|
|||||||
|
• Whether sample sizes are appropriate to the grain size of the material being sampled.
|
• The Competent Person considers the sample sizes to be appropriate given the general homogeneous nature of the mineralized zones. The two main types of mineralization are lithium
mineralization with high boron >/=5,000 parts per million (ppm) (HiB-Li) and lithium mineralization with low boron <5,000 ppm (LoB-Li). The HiB-Li mineralization occurs consistently throughout the B5, M5 and L6 target zones, while LoB-Li mineralization occurs throughout the M5, S5 and L6 units, and is not nuggety or confined to discreet high-grade and
low-grade bands.
|
|
APPENDIX D: JORC Code, 2012 Edition - Table 1
|
| Criteria |
JORC Code 2012 Explanation
|
Commentary | ||||||
|
Quality of assay data and laboratory tests
|
• The nature, quality and appropriateness of the assaying and laboratory procedures used and whether the technique is considered partial or total.
|
• The nature and quality of the assaying and laboratory procedures used include the following:
• All RC and core samples were processed, crushed, split, and then a sub-sample was pulverized by ALS Minerals in Reno, Nevada.
• All sub-samples were analysed by Aqua Regia with ICP mass spectrometry (ICP-MS) finish for 51 elements (including Lithium (Li)) and Boron (B) by NaOH fusion/ICP high grade analysis (>/=10,000 ppm B).
• Additionally, 95% of the 2018-2019 samples were analysed for Inorganic Carbon and 30% were analysed for Fluorine (F).
• The laboratory techniques are total.
• The Competent Person considers the nature and quality of the laboratory analysis methods and procedures to be appropriate for the type of mineralization.
|
||||||
|
• For geophysical tools, spectrometers, handheld XRF instruments, etc., the parameters used in determining the analysis including instrument make and model,
reading times, calibrations factors applied and their derivation, etc..
|
• Not applicable to this Report, no geophysical tools, spectrometers, handheld XRF instruments were used on the Project.
|
|
APPENDIX D: JORC Code, 2012 Edition - Table 1
|
| Criteria |
JORC Code 2012 Explanation
|
Commentary | ||||||
|
• Nature of quality control procedures adopted (e.g. standards, blanks, duplicates, external laboratory checks) and whether acceptable levels of accuracy
(i.e. lack of bias) and precision have been established.
|
• The following Quality Assurance and Quality Control (QA/QC) procedures were adopted for the various drilling programs:
• During the 2010-2012 program, Standard Reference Material (SRM) samples and a small number of field blanks were also inserted regularly into the
sample sequence to QA/QC of the laboratory analysis.
• For 2016-2017 program, a duplicate sample was collected every 20th primary sample. Field blanks and SRM’s were also inserted approximately every 25 samples to assess QA/QC.
• During the 2018-2019 program, QA/QC samples comprising 1 field blank and 1 SRM standard were inserted into each sample batch every 25 samples. Submission of field duplicates, laboratory
coarse/pulp replicates and umpire assays were submitted in later stages of the 2018-2019 drilling program.
• The Competent Person reviewed the SRM, field blanks and field duplicates and determined the following:
• SRMs: Review of the five SRMs used determined that there was a reasonable variability for Li between the upper and lower control limits (± 2 standard deviation (SD)), however B shows an overall bias towards lower than expected values (i.e. less than the mean) for all sample programs. For each of the 5 SRMs, there were some sample outliers (both low and high); however, the majority
fell within the control limits. There is a concern with the SRM sample submission protocol in that ioneer leaves the SRM standard name on the sample when submitting to the laboratory for analysis. This removes the blind nature from the SRM as
the laboratory can readily identify which standard sample is being evaluated and confirm what the expected values are for that SRM.
• Field Blanks: Review of the field blanks indicate that there is some variability in both the Li and B results. There are several samples that return higher than expected values, with an
increased number being from the 2018-2019 drilling program. Further review is required to determine if this is a result of the material used for field blanks (coarse dolomite) or a problem with the laboratory analysis.
• Field Duplicates: No field duplicates were submitted for the pre-2018 drilling programs. Review of the 230 field duplicate sample pairs from the 2018-2019 drilling program determined that
there was a strong correlation between each pair, as evidenced by an R2 value of 0.99 for Li.
• Umpire Laboratory Duplicates: 20 assay pulp rejects were sent from ALS to American Assay Laboratories (AAL) in Sparks, NV for umpire laboratory
analysis. Review of the 20 umpire duplicate pairs found a strong correlation between each pair, with B returning an R2 value of 0.98.
• The Competent Person reviewed the control charts produced for each SRM, field blank and field duplicate, and determined that there was an acceptable level of accuracy and precision for each
for the purpose of estimating Mineral Resources.
|
|
APPENDIX D: JORC Code, 2012 Edition - Table 1
|
| Criteria |
JORC Code 2012 Explanation
|
Commentary | ||||||
|
Verification of sampling and assaying
|
• The verification of significant intersections by either independent or alternative company personnel.
|
• Significant intersections have been verified by visual inspection of the drill core intervals by at least two ioneer geologists for all drilling programs.
|
||||||
|
• The use of twinned holes.
|
• One pair of twin drill holes at the same site were drilled during the 2010-2012 drilling program. The twin drill hole pairing comprises one RC drill hole (SBH-04) and one core drill hole
(SBHC-01).
• The Competent Person reviewed and assessed two drill holes and the variance for thickness and grade parameters were within acceptable levels.
|
|||||||
|
• Documentation of primary data, data entry procedures, data verification, data storage (physical and electronic) protocols.
|
• For the 2018-2019 drilling program, Newfields developed a series of field protocols covering all aspects of the exploration program, including surveying, logging, sampling and data
documentation. These protocols were followed throughout the 2018-2019 drilling program. Formal documentation of field protocols does not exist prior to the 2018-2019 program; however, the same senior personnel were involved in the earlier
programs and field protocols employed were essentially the same as those documented in the 2018-2019 protocols.
• Primary field data was captured on paper logs for the 2010-2012 drilling program, then transcribed into Microsoft (MS) Excel files. For the 2016
through 2019 drilling, all field data was captured directly into formatted MS Excel files by logging geologists. All primary field data was reviewed by the senior ioneer geologist.
• Data is stored in digital format in a MS Access database. This database was compiled, updated and maintained by Newfields personnel during the 2018-2019 drilling program.
• The Competent Person compiled all relevant information from various tabular data files provided by ioneer and Newfields into a MS Access database, which was reviewed and verified by the
Competent Person prior to inclusion in the geological model.
|
|
APPENDIX D: JORC Code, 2012 Edition - Table 1
|
| Criteria |
JORC Code 2012 Explanation
|
Commentary | ||||||
|
• Discuss any adjustment to assay data.
|
• There has been no adjustment to assay data.
|
|||||||
|
Location of data points
|
• Accuracy and quality of surveys used to locate drill holes (collar and down-hole surveys), trenches, mine workings and other locations used in Mineral
Resource estimation.
|
• Accuracy and quality of surveys used to locate drill holes is as follows:
• All inclined core drill holes were surveyed to obtain downhole deviation using a downhole Reflex Mems Gyros tool, except for SBH-72, which could not be surveyed due to tool error. Two core
drill holes (SBH-60, SBH-79) were surveyed using an Acoustic Televiewer instead of the Gyros tool.
• All 2018-2019 drill hole collars were surveyed using a differentially corrected GPS (DGPS).
• Locatable pre-2018 drill holes that were previously only surveyed by handheld GPS have been re-surveyed in 2019 using DPGS. Some pre-2018 drill holes could not be located by the surveyor in
2019, and the original locations were assumed to be correct.
• Upon completion, drill casing was removed, and drill collars were marked with a permanent concrete monument with the drill hole name and date recorded on a metal tag on the monument.
|
||||||
|
• Specification of the grid system used.
|
• All pre-2018 and 2018-2019 drill holes were originally surveyed using handheld GPS units in UTM Zone 11 North, North American Datum 1983 (NAD83)
coordinate system. Pre-2018 drill holes were re-surveyed using DPGS in NAD83 in 2017/2018.
• All 2018-2019 drill holes and locatable pre-2018 drill holes were re-surveyed in 2019 using DPGS in NAD83 coordinate system. All surveyed coordinates were subsequently converted to Nevada
State Plane Coordinate System of 1983, West Zone (NVSPW 1983) for use in developing the geological model. Those holes that could not be located had the original coordinates converted to NVSPW 1983 and
their locations verified against the original locations.
|
|
APPENDIX D: JORC Code, 2012 Edition - Table 1
|
| Criteria |
JORC Code 2012 Explanation
|
Commentary | ||||||
|
• Quality and adequacy of topographic control.
|
• The quality and adequacy of the topographic surface and the topographic control is very good based on comparison against survey monuments, surveyed drill hole collars and other surveyed
surface features.
• A 2018 satellite survey with an accuracy of ± 0.17 m was produced for the Project by PhotoSat Information Ltd. The final report generated by PhotoSat stated that the difference between the
satellite and ioneer provided ground survey control points was less than 0.8 m.
• The topographic survey was prepared in NAD83, which was converted to NVSPW 1983 by Newfields prior to geological modelling.
|
|||||||
|
Data spacing and distribution
|
• Data spacing for reporting of Exploration Results.
|
• Drill holes are generally spaced between 90 m and 170 m on east-west cross-section lines spaced approximately 180 m apart. There was no distinction between RC and core holes for the purpose
of drill hole spacing.
• For the 2018-2019 drilling program, there were multiple occurrences where several inclined drill holes were drilled from the same drill pad and oriented at varying angles away from each
other. The collar locations for these inclined drill holes drilled from the same pad varied in distance from 0.3 m to 6.0 m apart; intercept distances on the floors of the target units were typically in excess of 90 m spacing.
|
||||||
|
• Whether the data spacing and distribution is sufficient to establish the degree of geological and grade continuity appropriate for the Mineral Resource and
Ore Reserve estimation procedure(s) and classifications applied.
|
• The spacing is considered sufficient to establish geological and grade continuity appropriate for a Mineral Resource estimation.
|
|||||||
|
• Whether sample compositing has been applied.
|
• Samples were composited to 1.52 m intervals honouring lithological boundaries prior to grade estimation. The 1.52 m sample composite length represents the modal value of the sample length
distribution.
|
|
APPENDIX D: JORC Code, 2012 Edition - Table 1
|
| Criteria |
JORC Code 2012 Explanation
|
Commentary | ||||||
|
Orientation of data in relation to geological structure
|
• Whether the orientation of sampling achieves unbiased sampling of possible structures and the extent to which this is known, considering the deposit type.
|
• Drill holes were angled between -45 and -90 degrees from horizontal and at an azimuth of between 0- and 332-degrees.
• Inclined drill holes orientated between 220- and 332-degrees azimuth introduced minimal sample bias, as they primarily intercepted the mineralization at angles near orthogonal (101 drill
holes with intercept angles between 70-90 degrees) to the dip of the beds, approximating true-thickness.
|
||||||
|
• If the relationship between the drilling orientation and the orientation of key mineralised structures is considered to have introduced a sampling bias,
this should be assessed and reported if material.
|
• Inclined drill holes orientated between 0- and 220-degrees azimuth, especially those that were drilled at between 20- and 135-degrees azimuth, generally intercepted the beds down dip (7 drill
holes with intercept angles between 20-70 degrees), exaggerating the mineralized zone widths in these drill holes.
|
|||||||
|
Sample security
|
• The measures taken to ensure sample security.
|
• The measures taken to ensure sample security include the following:
• For the 2010-2012 drill holes, samples were securely stored on-site and then collected from site by ALS. Chain of custody forms were maintained by ALS.
• For the 2016-2017 drill holes, samples were securely stored on-site and then collected from site by ALS and transported to the laboratory by truck. Chain of custody forms were maintained by
ALS.
• For the 2018-2019 drill holes, core was transported daily by ioneer and/or Newfields personnel from the drill site to the ioneer secure core shed (core storage) facility in Tonopah. Core
awaiting logging was stored in the core shed until it was logged and sampled, at which time it was stored in secured sea cans inside a fenced and locked core storage facility on site. Samples were sealed in poly-woven sample bags, labelled
with a pre-form numbered and barcoded sample tag, and securely stored until shipped to or dropped off at the ALS laboratory in Reno by Newfields personnel. Chain of custody forms were maintained by Newfields and ALS.
|
|
APPENDIX D: JORC Code, 2012 Edition - Table 1
|
| Criteria |
JORC Code 2012 Explanation
|
Commentary | ||||||
|
Audits or reviews
|
• The results of any audits or reviews of sampling techniques and data.
|
• There were no audits performed on the RC sampling or for the pre-2018 drilling programs.
• The Competent Person reviewed the core and sampling techniques during a site visit in December 2018. The Competent Person found that the sampling techniques were appropriate for collecting
data for the purpose of preparing geological models and Mineral Resource estimates. The following recommendations were submitted to ioneer for consideration following the site visit:
• Update 2018-2019 collar survey locations using high-resolution survey methods such as DGPS as soon as possible following completion of the 2018-2019 drilling.
• Include survey pick-up of any pre-2018 drill holes identified in the drill hole database as being surveyed by handheld, non-differential GPS.
• Update surface mapping to adjust surficial geological contacts and structures based on revised interpretation and understanding of geology from the current drilling program.
• Revise QA/QC protocol to include field duplicates, laboratory replicates (coarse and pulp replicates) and check assay analyses at a second independent commercial laboratory.
• Change SRM insertion procedure to remove the SRM name/number and identifiers other than the regular sample number prior to submitting the sample to the laboratory for analyses.
• Exclude trench data from the modelling process based on visual inspection of the sub-crop trenches and the reliability and representativeness of trench analytical data used in previous model
iterations.
|
|
APPENDIX D: JORC Code, 2012 Edition - Table 1
|
SECTION 2 REPORTING OF EXPLORATION RESULTS
(Criteria listed in the preceding section also apply to this section.)
|
Criteria
|
JORC Code 2012 Explanation
|
Commentary
|
||||||
|
Mineral tenement and land tenure status
|
• Type, reference name/number, location and ownership including agreements or material issues with third parties such as joint ventures, partnerships,
overriding royalties, native title interests, historical sites, wilderness or national park and environmental settings.
|
• The mineral tenement and land tenure for the South Basin of Rhyolite Ridge (the Project) comprise 386 unpatented Lode Mining Claims (totalling approximately 3,150 hectare (Ha)); claim groups SLB, SLM and RR, spatial extents of which are presented in maps and tables within the body of the Report are held by ioneer Minerals Corporation, a wholly owned subsidiary of ioneer. The
Competent Person has relied upon information provided by ioneer regarding mineral tenement and land tenure for the Project; the Competent Person has not performed any independent legal verification of the mineral tenement and land tenure.
• ioneer has entered into a proposed joint venture agreement with Sibanye-Stillwater, the details of which are presented in the September 16, 2021, ASX press release by ioneer.
• With the exception of the proposed joint venture agreement with Sibanye-Stillwater, the Competent Person is not aware of any agreements or material issues with third parties such as joint
ventures, partnerships, overriding royalties, native title interests, historical sites, wilderness or national park and environmental settings relating to the 386 Lode Mining Claims for the Project.
• The mineral tenement and land tenure referenced above excludes 241 additional unpatented Lode Mining Claims (totalling approximately 2,000 Ha) for the North Basin which are located outside
of the current South Basin Project Area presented in this Report. These additional claims are held by ioneer subsidiaries (NLB claim group; 160 claims) or ioneer holds an option to acquire 100% ownership of the claims (BH claim group; 81
claims).
|
||||||
|
• The security of the tenure held at the time of reporting along with any known impediments to obtaining a licence to operate in the area.
|
• There are no identified concerns regarding the security of tenure nor are there any known impediments to obtaining a license to operate within the limits of the Project. The 386 unpatented
Lode Mining Claims for the Project are located on federal land and are administered by the United States Department of the Interior - Bureau of Land Management (BLM).
|
|
APPENDIX D: JORC Code, 2012 Edition - Table 1
|
|
Criteria
|
JORC Code 2012 Explanation
|
Commentary
|
||||||
|
Exploration done by other parties
|
• Acknowledgment and appraisal of exploration by other parties.
|
• There have been two previous exploration campaigns targeting Li-B mineralization at the Project site.
• US Borax conducted surface sampling and drilling in the 1980s, targeting B mineralization, with less emphasis on Li mineralization. A total of 57
drill holes (totalling approximately 14,900 m) were drilled in the North Borate Hills area, with an additional 12 drill holes (unknown total meterage) in the South Basin area. These drill holes were not available for use in the current Study.
• American Lithium Minerals Inc and Japan Oil, Gas and Metals National Corporation (JOGMEC) conducted further Li
exploration in the South Basin area in 2010-2012. The exploration included at least 465 surface and trench samples and 36 drill holes (totalling approximately 8,800 m), of which 21 were core and 15 were RC. Data collected from this program,
including drill core, was made available to ioneer. The Competent Person reviewed the data available from this program and believes this exploration program, except for the trench data, was conducted appropriately and the information
generated is of high enough quality to include in preparing the current geological model and Mineral Resource estimate.
• Due to concerns regarding the ability to reliably correlate the trenches with specific geological units as well as concerns regarding representivity of samples taken from incomplete
exposures of the units in the trenches, the Competent Person does not feel the trench sample analytical results are appropriate for use and has excluded them from use in preparing the geological model and Mineral Resource estimate.
|
||||||
|
Geology
|
• Deposit type, geological setting and style of mineralisation.
|
• The HiB-Li and LoB-Li mineralization at Rhyolite Ridge occurs in two separate Miocene sedimentary basins; the North Basin and the South Basin, located within the Silver Peak Range in the
Basin and Range terrain of Nevada, USA. The South Basin is the focus of the Study presented in this Report and the following is focused on the geology and mineralization of the South Basin.
• The South Basin stratigraphy comprises lacustrine sedimentary rocks of the Cave Spring Formation overlaying volcanic flows and volcaniclastic rocks of the Rhyolite Ridge Volcanic unit. The
Rhyolite Ridge Volcanic unit is dated at approximately 6 mega-annum (Ma) and comprises rhyolite tuffs, tuff breccias and flows. The Rhyolite Ridge Volcanic rocks are underlain by sedimentary rocks of
the Silver Peak Formation.
|
|
APPENDIX D: JORC Code, 2012 Edition - Table 1
|
|
Criteria
|
JORC Code 2012 Explanation
|
Commentary | ||||||
| |
|
• The Cave Spring Formation comprises a series of 11 sedimentary units deposited in a lacustrine environment, as shown in the following table. Within the study area the Cave Spring Formation
can reach total thickness in excess of 300 m. Age dating of overlying units outside of the area and dates for the underlying Rhyolite Ridge Volcanic unit bracket deposition of the Cave Spring Formation between 4-6 Ma; this relatively young
geological age indicates limited time for deep burial and compaction of the units. The Cave Spring Formation units are generally laterally continuous over several miles across the extent of the South Basin; however, thickness of the units can
vary due to both primary depositional and secondary structural features. The sedimentary sequence generally fines upwards, from coarse clastic units at the base of the formation, upwards through siltstones, marls and carbonate units towards
the top of the sequence.
• The key mineralized units are in the Cave Spring Formation and are, from top to bottom, the M5 (high-grade Li, low- to moderate-grade B bearing carbonate-clay rich marl), the B5 (high-grade
B, moderate-grade Li marl), the S5 (low- to moderate Li, very low B) and the L6 (broad zone of laterally discontinuous low- to high-grade Li and B mineralized horizons within a larger low-grade to barren sequence of siltstone-claystone). The
sequence is marked by a series of four thin (generally on the scale of several meters or less) coarse gritstone layers (G4 through G7); these units are interpreted to be pyroclastic deposits that blanketed the area. The lateral continuity
across the South Basin along with the distinctive visual appearance of the gritstone layers relative to the less distinguishable sequence of siltstone-claystone-marl that comprise the bulk of the Cave Spring Formation make the four grit stone
units good marker horizons within the stratigraphic sequence.
• The Cave Springs Formation is unconformably overlain by a unit of poorly sorted alluvium, ranging from 0 to 40 m (mean of 20 m) within the Study Area. The alluvium is unconsolidated and
comprises sand through cobble sized clasts (with isolated occurrences of large boulder sized clasts) of the Rhyolite Ridge Volcanic Rocks and other nearby volcanic units.
|
|
APPENDIX D: JORC Code, 2012 Edition - Table 1
|
| Criteria |
JORC Code 2012 Explanation
|
Commentary | ||||||
![]() |
|
APPENDIX D: JORC Code, 2012 Edition - Table 1
|
| Criteria |
JORC Code 2012 Explanation
|
Commentary | ||||||
|
• Structurally, the South Basin is folded into a broad, open syncline with the sub-horizontal fold axis oriented approximately north-south representing the long axis of the basin. The syncline
is asymmetric, with moderate to locally steep dips along the western limb, a flat central area, and interpreted steep dips on the eastern edge. The stratigraphy is further folded, including one significant southeast plunging syncline located
in the southern part of the study area. The basin is bounded along its western and eastern margins by regional scale high angle faults of unknown displacement, while localized steeply dipping normal, reverse and strike-slip faults transect
the Cave Spring formation throughout the basin. Displacement on these faults is generally poorly known but most appear to be on the order of tens of meters of displacement although several located along the edge of the basin may have
displacements greater than 30 m.
• HiB-Li and LoB-Li mineralization is interpreted to have been emplaced by hydrothermal/epithermal fluids travelling up the basin bounding faults; based on HiB-Li and LoB-Li grade distribution
and continuity it is believed the primary fluid pathway was along the western bounding fault. Differential mineralogical and permeability characteristics of the various units within the Cave Spring Formation resulted in the preferential
emplacement of HiB-Li bearing minerals in the B5 and L6 units and LoB-Li bearing minerals in the M5, S5 and L6 units. HiB-Li mineralization occurs in isolated locations in some of the other units in the sequence, but with nowhere near the
grade and continuity observed in the aforementioned units.
|
||||||||
|
Drill hole Information
|
• A summary of all information material to the understanding of the exploration results including a tabulation of the
following information for all Material drill holes:
o easting and northing of the drill hole collar
o elevation or RL (Reduced Level – elevation above sea level in metres) of the drill hole collar
o dip and azimuth of the hole
o down hole length and interception depth
o hole length.
|
• Exploration Results are not being reported.
• A summary table providing key details for all identified drill holes for the Project is presented by type and drilling campaign in the following table:
![]() |
|
APPENDIX D: JORC Code, 2012 Edition - Table 1
|
| Criteria |
JORC Code 2012 Explanation
|
Commentary | ||||||
|
• If the exclusion of this information is justified on the basis that the information is not Material and this exclusion does not detract from the
understanding of the report, the Competent Person should clearly explain why this is the case.
|
• Of the 112 drill holes reviewed, 108 (42 RC and 66 core) were included in the geological model and 4 were omitted. One RC twin hole was omitted in favour of the cored hole at the same
location. Three water/geotechnical drill holes were omitted due to a lack of lithology and quality data relevant to the geological model.
|
|||||||
|
Data aggregation methods
|
• In reporting Exploration Results, weighting averaging techniques, maximum and/or minimum grade truncations (e.g. cutting of high grades) and cut-off grades
are usually Material and should be stated.
|
• Exploration Results are not being reported.
• All grade parameters presented as part of the Mineral Resource estimates prepared by Golder are presented as mass weighted grades.
• Drill core samples were composited to 1.52 m composite lengths prior to interpolation of grade data into the block model. Composite lengths honoured geological contacts (i.e. composites did
not span unit contacts). The composite length was selected based on the median sample length from the drill hole assay database.
• No minimum bottom cuts or maximum top cuts were applied to the thickness or grade data used to construct the geological models. Restricted interpolation was applied to B grade data for units
other than the targeted mineralized units (B5, M5 and L6; discussed further in the Estimation and Modelling Techniques section of this Table 1).
• A cut-off grade of 5,000 ppm B for the HiB-Li mineralization and 1,090 ppm Li for the LoB-Li mineralization was applied during the Mineral Resource estimation process for the purpose of
establishing reasonable prospects of eventual economic extraction based on high level mining, metallurgical and processing grade parameters identified by mining, metallurgical and processing studies performed to date on the Project.
|
||||||
|
• Where aggregate intercepts incorporate short lengths of high grade results and longer lengths of low grade results, the procedure used for such aggregation
should be stated and some typical examples of such aggregations should be shown in detail.
|
• Not applicable as individual intercepts or Exploration Results are not being reported.
|
|||||||
|
• The assumptions used for any reporting of metal equivalent values should be clearly stated.
|
• Metal equivalents were not used in the Mineral Resource estimates prepared by Golder.
|
|
APPENDIX D: JORC Code, 2012 Edition - Table 1
|
| Criteria |
JORC Code 2012 Explanation
|
Commentary | ||||||
|
Relationship between mineralisation widths and intercept lengths
|
• These relationships are particularly important in the reporting of Exploration Results.
|
• All drill hole intercepts presented in the Report are down hole thickness not true thickness. As discussed in the Orientation of Data section of this Table 1, most drill hole intercepts are
approximately orthogonal to the dip of the beds (intercept angles between 70-90 degrees).
|
||||||
|
• If the geometry of the mineralisation with respect to the drill hole angle is known, its nature should be reported.
|
• Based on the geometry of the mineralization, it is reasonable to treat all samples collected from inclined drill holes at intercept angles of greater than 70 degrees as representative of the
true thickness of the zone sampled.
|
|||||||
|
• If it is not known and only the down hole lengths are reported, there should be a clear statement to this effect (e.g. ‘down hole length, true width not
known’).
|
• Not applicable as individual down hole intercepts or Exploration Results are not being reported.
|
|||||||
|
Diagrams
|
• Appropriate maps and sections (with scales) and tabulations of intercepts should be included for any significant discovery being reported These should
include, but not be limited to a plan view of drill hole collar locations and appropriate sectional views.
|
• Appropriate plan maps and sections are appended to the Report.
|
||||||
|
Balanced reporting
|
• Where comprehensive reporting of all Exploration Results is not practicable, representative reporting of both low and high grades and/or widths should be
practiced to avoid misleading reporting of Exploration Results.
|
• Exploration Results are not being reported.
|
||||||
|
Other substantive exploration data
|
• Other exploration data, if meaningful and material, should be reported including (but not limited to): geological observations; geophysical survey results;
geochemical survey results; bulk samples – size and method of treatment; metallurgical test results; bulk density, groundwater, geotechnical and rock characteristics; potential deleterious or contaminating substances.
|
• Surficial geological mapping performed by a senior ioneer geologist was used in support of the drill holes to define the outcrops and subcrops as well as bedding dip attitudes in the
geological modelling. Mapped geological contacts and faults were imported into the model and used as surface control points for the corresponding beds or structures.
|
||||||
|
Further work
|
• The nature and scale of planned further work (e.g. tests for lateral extensions or depth extensions or large-scale step-out drilling).
|
• Additional in-fill drilling and sampling may be performed based on the results of current mining project studies
|
||||||
|
• Diagrams clearly highlighting the areas of possible extensions, including the main geological interpretations and future drilling areas, provided this
information is not commercially sensitive.
|
• No diagrams are applicable as no additional areas within the South Basin are recommended for further exploration at this time.
|
|
APPENDIX D: JORC Code, 2012 Edition - Table 1
|
SECTION 3 ESTIMATION AND REPORTING OF MINERAL RESOURCES
(Criteria listed in section 1, and where relevant in section 2, also apply to this section.)
|
Criteria
|
JORC Code 2012 explanation
|
Commentary
|
||||||
|
Database integrity
|
• Measures taken to ensure that data has not been corrupted by, for example, transcription or keying errors, between its initial collection and its use for
Mineral Resource estimation purposes.
|
• Measures taken to ensure the data has not been corrupted by transcription or keying errors or omissions included recording of drill hole data and observations by the logging geologists using
formatted logging sheets in Microsoft (MS) Excel. Data and observations entered into the logging sheets were reviewed by senior ioneer and Newfield’s geologists prior to importing the data into the MS
Access drill hole database.
• Golder evaluated the tabular data provided by ioneer for errors or omissions as part of the data validation procedures described in the following section.
|
||||||
|
• Data validation procedures used.
|
• Golder performed data validation on the drill hole database records using available underlying data and documentation including but not limited to original drill hole descriptive logs, core
photos and laboratory assay certificates. Drill hole data validation checks were performed in MS Access using a series of in-house data checks to evaluate for common drill hole data errors including, but not limited to, data gaps and
omissions, overlapping lithology or sample intervals, miscorrelated units, drill hole deviation errors and other indicators of data corruption including transcription and keying errors.
• Database assay values for every sample were visually compared to the laboratory assay certificates to ensure the tabular assay data was free of errors or omissions.
• Proposed corrections, additions or revisions to the data set were reviewed with ioneer and Newfield’s senior geologists and any updates to the data were incorporated into the geological
database
|
|||||||
|
Site visits
|
• Comment on any site visits undertaken by the Competent Person and the outcome of those visits.
|
• The WSP Competent Person Jerry DeWolfe, P.Geo. made a personal inspection site visit was performed on the Project site from December 3rd to 5th 2018 for the Project.
• During the site visit the WSP Competent Person visited the ioneer core shed in Tonopah NV, and the South Basin area of the Rhyolite Ridge Project site, which is the focus of the current
exploration and resource evaluation efforts by ioneer.
|
|
APPENDIX D: JORC Code, 2012 Edition - Table 1
|
| Criteria |
JORC Code 2012 explanation
|
Commentary
|
||||||
|
• The WSP Competent Person observed the active drilling, logging and sampling process and interviewed site personnel regarding exploration drilling, logging, sampling and chain of custody
procedures.
• The outcome of the site visit was that the WSP Competent Person developed an understanding of the general geology of the Rhyolite Ridge Project. The WSP Competent Person was also able to
visually confirm the presence of a selection of monumented drill holes from each of the previous drilling programs as well as to observe drilling, logging and sampling procedures during the current drilling program and to review documentation
for the logging, sampling and chain of custody protocols for previous drilling programs.
|
||||||||
|
• If no site visits have been undertaken indicate why this is the case.
|
• Not applicable.
|
|||||||
|
Geological interpretation
|
• Confidence in (or conversely, the uncertainty of) the geological interpretation of the mineral deposit.
|
• The WSP Competent Person is confident that the geological interpretation of the mineral deposit is reasonable for the purposes of Mineral Resource estimation.
|
||||||
|
• Nature of the data used and of any assumptions made.
|
• The data used in the development of the geological interpretation included drill hole data and observations collected from 66 core and 42 RC drill holes, supplemented by surface mapping of
outcrops and faults performed by ioneer personnel. Regional scale public domain geological maps and studies were also incorporated into the geological interpretation.
• It is assumed that the mineralized zones are continuous between drill holes as well as between drill holes and surface mapping. It is also assumed that grades vary between drill holes based
on a distance-weighted interpolator.
|
|||||||
|
• The effect, if any, of alternative interpretations on Mineral Resource estimation.
|
• There are no known alternative interpretations.
|
|||||||
|
• The use of geology in guiding and controlling Mineral Resource estimation.
|
• Geology was used directly in guiding and controlling the Mineral Resource estimation. The mineralized zones were modelled as stratigraphically controlled HiB-Li and LoB-Li deposits. As such,
the primary directions of continuity for the mineralization are horizontally within the preferentially mineralized B5, M5, S5 and L6 geological units.
|
|
APPENDIX D: JORC Code, 2012 Edition - Table 1
|
| Criteria |
JORC Code 2012 explanation
|
Commentary
|
||||||
|
• The factors affecting continuity both of grade and geology.
|
• The primary factor affecting the continuity of both geology and grade is the lithology of the geological units. HiB-Li mineralization is favourably
concentrated in marl-claystone of the B5 and L6 units and LoB-Li in the M5, S5 and L6 units. Mineralogy of the units also has a direct effect on the continuity of the mineralization, with elevated B grades in the B5 and M5 units associated
with a distinct reduction in carbonate and clay content in the units, while higher Li values tend to be associated with elevated carbonate content in these units and sometimes k-felspar.
• Additional factors affecting the continuity of geology and grade include the spatial distribution and thickness of the host rocks which have been impacted by both syn-depositional and
post-depositional geological processes (i.e. localized faulting, erosion and so forth).
|
|||||||
|
Dimensions
|
• The extent and variability of the Mineral Resource expressed as length (along strike or otherwise), plan width, and depth below surface to the upper and
lower limits of the Mineral Resource.
|
• The Mineral Resource evaluation presented in this Report covers an area of approximately 275 Ha within the South Basin of Rhyolite Ridge. The Mineral Resource plan dimensions, defined by the
spatial extent of the B5 unit Inferred classification limits, are approximately 2,900 m North-South by 1,600 m East-West. The upper and lower limits of the Mineral Resource span from surface, where the mineralized units outcrop locally,
through to a maximum depth of 400 m below surface for the base of the lower mineralized zone (L6 unit).
• Variability of the Mineral Resource is associated primarily with the petrophysical and geochemical properties of the individual geological units in the Cave Spring Formation. These properties
played a key role in determining units that were favourable for hosting HiB-Li and LoB-Li mineralization versus those that weren’t.
• On a basin scale, proximity/distance relative to the interpreted source pathways for the mineralizing fluids is a key component in grade distribution and variability across the
deposit; Li and B grades appear highest in the southwest portion of the South Basin, proximal to the western bounding fault of the basin.
|
|
APPENDIX D: JORC Code, 2012 Edition - Table 1
|
| Criteria |
JORC Code 2012 explanation
|
Commentary | ||||||
|
Estimation and modelling techniques
|
• The nature and appropriateness of the estimation technique(s) applied and key assumptions, including treatment of extreme grade values, domaining,
interpolation parameters and maximum distance of extrapolation from data points. If a computer assisted estimation method was chosen include a description of computer software and parameters used.
|
• Geological modelling and Mineral Resource estimation for the Project was performed under the supervision of the Competent Person.
• Based on a statistical analysis, extreme B grade values were identified in some of the units other than the targeted B5, M5 and L6 units. As a result, restricted interpolation was applied to
B grades in units other than the B5, M5 and L6.
• The geological model was developed as a gridded surface stratigraphic model and a stratigraphically constrained grade block model using MineScape (v6.1.1) StratModel and BlockModel, which
are computer-assisted geological, grade modelling, and estimation software applications.
• Domaining in the model was constrained by the roof and floor surfaces of the geological units. The unit boundaries were modelled as hard boundaries, with samples interpolated only within the
unit in which they occurred.
• Key modelling and estimation parameters included the following:
![]() |
|
APPENDIX D: JORC Code, 2012 Edition - Table 1
|
| Criteria |
JORC Code 2012 explanation
|
Commentary | ||||||
| |
• The availability of check estimates, previous estimates and/or mine production records and whether the Mineral Resource estimate takes appropriate account
of such data.
|
• The Table below presents a summary comparison of the current March 31, 2023 Mineral Resource estimate against the previous Mineral Resource estimate for the Project, prepared by Golder (now
WSP) in April 2020 in association with the 2020 DFS.
![]() • There has been no HiB-Li or LoB-Li production on the Project to date.
|
||||||
|
• The assumptions made regarding recovery of by-products.
|
• No by-products are being considered for recovery at present.
|
|||||||
|
• Estimation of deleterious elements or other non-grade variables of economic significance (e.g. sulphur for acid mine drainage characterisation).
|
• In addition to Li and B, the geological model also included 12 additional non-grade elements (Sr, Ca, Mg, Na, K, As, Rb, Cs, Mo, Fe, Al, W) to allow for calculation of acid consumption
values for the metallurgical process. No deleterious elements were estimated.
|
|||||||
|
• In the case of block model interpolation, the block size in relation to the average sample spacing and the search employed.
|
• The stratigraphic gridded surface model was developed using a 7.62 m regularized grid. The grade block model was developed from the stratigraphic model using a 15.24 m North-South by 15.24 m
East-West by 1.52 m vertical parent block dimension with sub-cell dimensions of 3.81 m by 3.81 m by 0.38 m. The grid cell and block size dimensions represent 25 percent of the nominal drill hole spacing across the model area.
• Grade interpolation into the model blocks was performed using an Inverse Distance Squared (ID2) interpolator
with up to four search passes with search distances of 152.4 m, 304.8 m, 609.6 m and 6,096 m.
|
|
APPENDIX D: JORC Code, 2012 Edition - Table 1
|
| Criteria |
JORC Code 2012 explanation
|
Commentary | ||||||
|
• Any assumptions behind modelling of selective mining units.
|
• Assumptions relating to selective mining units were based on the interpretation that the HiB-Li mineralization encountered is stratigraphically constrained and that mineralized and
non-mineralized units can be selectively separated by existing mining and processing methods.
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• Any assumptions about correlation between variables.
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• No assumptions or calculations relating to the correlation between variables were made at this time.
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• Description of how the geological interpretation was used to control the resource estimates.
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• The geological interpretation was used to control the Mineral Resource estimate by developing a contiguous stratigraphic model (all units in the sequence were modelled) of the host rock
units deposited within the basin, the roof and floor contacts of which then served as hard contacts for constraining the grade interpolation. Grade values were interpolated within the geological units using only samples intersected within
those units; sub-celling was applied to allow for improved definition of geological contacts relative to the model blocks at the upper and lower contacts of the units.
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• Discussion of basis for using or not using grade cutting or capping.
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• Grade capping or cutting was not applied for the targeted mineralized units B5, M5, S5 and L6 as a statistical analysis of the grade data indicated there was no bias or influence by extreme
outlier grade values.
• Restricted interpolation of Boron grade data was applied in place of grade cutting or capping in the other units on the model besides the targeted mineralized units B5, M5 and L6; to allow
for use of all validated grade values while limiting the potential impact of overestimating spatially isolated high-grade results in the generally unmineralized units. Restricted interpolation controls were not applied to any other grade
parameters. Mineral Resources were not estimated for the other units however grade was interpolated to allow for potential mining dilution evaluations during later studies.
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• The process of validation, the checking process used, the comparison of model data to drill hole data, and use of reconciliation data if available.
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• The geological model validation and review process involved visual inspection of drill hole data as compared to model geology and grade parameters using plan isopleth maps and 180 m spaced
cross-sections through the model. Drill hole and model values were compared statistically as well as via along-strike and down-dip swath plots.
• No reconciliation data is available because the property is not in production.
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APPENDIX D: JORC Code, 2012 Edition - Table 1
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| Criteria |
JORC Code 2012 explanation
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Commentary | ||||||
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Moisture
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• Whether the tonnages are estimated on a dry basis or with natural moisture, and the method of determination of the moisture content.
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• The estimated Mineral Resource tonnages are presented on a dry basis.
• A moisture content of 5% for the mineralized units has been assumed for mining and other modifying factors studies currently underway but should be evaluated as part of future analytical
programs.
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Cut-off parameters
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• The basis of the adopted cut-off grade(s) or quality parameters applied.
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• The Mineral Resource estimate presented in this Report has been constrained by the application of an optimized Mineral Resource pit shell. The Mineral Resource pit shell was developed using
Maptek Vulcan Mine Planning software.
• The Mineral Resource estimate assumes the use of two processing streams: one which can process ore with boron content greater than 5,000 ppm and one which can process ore with boron content
less than 5,000 ppm.
• Key input parameters and assumptions for the Mineral Resource pit shell included the following:
• B cut-off grade of 5,000 ppm for HiB-Li processing stream and no B cut-off grade for LoB-Li processing stream
• No Li cut-off grade for HiB-Li processing stream and Li cut-off grade of 1,090 ppm for LoB-Li processing stream
• Overall pit slope angle of 35 degrees in the alluvium and 42 degrees in other rock units (wall angle guidance provided by EnviroMINE, Inc., who developed the geotechnical design).
• Mining cost of US$2.67/tonne (t) plus US$0.0059/t-vertical foot of haulage.
• Ore processing and grade control costs of US$45.45/t of ore for HiB-Li Processing Stream and US$40.69/t of ore for LoB-Li Processing Stream.
• Boron and Li recovery of 83.5% and 81.8% respectively for HiB-Li Processing Stream.
• Boron Recovery for LoB-Li Processing Stream variable by lithology as follows: 72% in M5 Unit, 79.5% in B5 unit, 75% in S5 unit, and 81% in L6 unit.
• Lithium Recovery for LoB-Li Processing Stream variable by lithology as follows: 76% in M5 unit, 85% in B5 unit, 85% in S5 unit, and 86% in L6 unit.
• Boric Acid sales price of US$700/t.
• Lithium Carbonate sales price of US$10,000/t.
• Sales/Transport costs of US$160/t of product.
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APPENDIX D: JORC Code, 2012 Edition - Table 1
|
| Criteria |
JORC Code 2012 explanation
|
Commentary | ||||||
|
Mining factors or assumptions
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• Assumptions made regarding possible mining methods, minimum mining dimensions and internal (or, if applicable, external) mining dilution. It is always
necessary as part of the process of determining reasonable prospects for eventual economic extraction to consider potential mining methods, but the assumptions made regarding mining methods and parameters when estimating Mineral Resources
may not always be rigorous. Where this is the case, this should be reported with an explanation of the basis of the mining assumptions made.
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• The Mineral Resource estimate presented in this Report was developed with the assumption that the HiB-Li mineralization within the Mineral Resource pit shell, as described in the preceding
section, has a reasonable prospect for eventual economic extraction using current conventional open pit mining methods.
• The basis of the mining assumptions made in establishing the reasonable prospects for eventual economic extraction of the HiB-Li mineralization are based on preliminary results from mine
design and planning work that is in-progress as part of an ongoing Feasibility Study for the Project.
• Except for the Mineral Resource pit shell criteria discussed in the preceding section, no other mining factors, assumptions or mining parameters such as mining recovery, mining loss or
dilution have been applied to the Mineral Resource estimate presented in this Report.
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Metallurgical factors or assumptions
|
• The basis for assumptions or predictions regarding metallurgical amenability. It is always necessary as part of the process of determining reasonable
prospects for eventual economic extraction to consider potential metallurgical methods, but the assumptions regarding metallurgical treatment processes and parameters made when reporting Mineral Resources may not always be rigorous. Where
this is the case, this should be reported with an explanation of the basis of the metallurgical assumptions made.
|
• The basis of the metallurgical assumptions made in establishing the reasonable prospects for eventual economic extraction of the HiB-Li mineralization are based on results from metallurgical
and material processing work that was developed as part of the ongoing Feasibility Study for the Project. This test work was performed using current processing and recovery methods for producing Boric acid and Lithium carbonate products
• A second process stream to recover Li from low boron mineralized (LoB-Li) units is being developed. Current results indicate a reasonable process and expectation for economic extraction of
the LoB-Li from the S5, M5 and L6 units. This test work was performed using current processing and recovery methods for producing Boric acid and Lithium carbonate products.
|
|
APPENDIX D: JORC Code, 2012 Edition - Table 1
|
| Criteria |
JORC Code 2012 explanation
|
Commentary | ||||||
|
Environment-al factors or assumptions
|
• Assumptions made regarding possible waste and process residue disposal options. It is always necessary as part of the process of determining reasonable
prospects for eventual economic extraction to consider the potential environmental impacts of the mining and processing operation. While at this stage the determination of potential environmental impacts, particularly for a greenfields
project, may not always be well advanced, the status of early consideration of these potential environmental impacts should be reported. Where these aspects have not been considered this should be reported with an explanation of the
environmental assumptions made.
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• The project will require waste and process residue disposal. Assumptions have been made that all environmental requirements will be achieved through necessary studies, designs and permits.
• Currently, baseline studies and detailed designs have been completed for both waste and process residue disposal facilities.
• In December 2022, the United States Fish and Wildlife Service (USFWS) listed Tiehm’s buckwheat as an endangered species under the Endangered Species Act (ESA) and has designated critical
habitat by way of applying a 500 m radius around several distinct plant populations that occur on the Project site. Ioneer is committed to the protection and conservation of the Tiehm’s buckwheat. The Project’s Mine Plan of Operations
submitted to the BLM in July 2022 and currently under NEPA review has no direct impact on Tiehm’s buckwheat and includes measures to minimise and mitigate for indirect impacts within the designated critical habitat areas identified.
• The mineral resource pit shell used to constrain the March 31, 2023, mineral resource estimate was not adjusted to account for any impacts from avoidance of Tiehm’s buckwheat or minimisation
of disturbance within the designated critical habitat. Estimates run inside the avoidance polygons identified 29.4 Mt at 1,650 ppm Li and 9,000 ppm B (both HiB-Li and LoB-Li streams combined), reflecting approximately 8% of the March 2023
global Mineral Resource estimate for the Project. The tonnes and grade within the avoidance polygons have not been removed from the Mineral Resources for the March 2023 estimate. Environmental and permitting assumptions and factors will be
taken into consideration during future modifying factors studies for the Project. These permitting assumptions and factors may result in potential changes to the Mineral Resource footprint in the future.
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Bulk density
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• Whether assumed or determined. If assumed, the basis for the assumptions. If determined, the method used, whether wet or dry, the frequency of the
measurements, the nature, size and representativeness of the samples.
|
• The density values used to convert volumes to tonnages were assigned on a by-geological unit basis using mean values calculated from 249 density samples collected from drill core during the
2010-2012 and 2018-2019 drilling programs. The density analyses were performed using the water displacement method for density determination, with values reported in dry basis.
• The application of assigned densities by geological unit assumes that there will be minimal variability in density within each of the units across their spatial extents within the Project
area. The use of assigned density with a very low number of samples, as is the case with several waste units, is a factor that increases the uncertainty and represents a risk to the Mineral Resource estimate confidence.
|
|
APPENDIX D: JORC Code, 2012 Edition - Table 1
|
| Criteria |
JORC Code 2012 explanation
|
Commentary | ||||||
| |
• The bulk density for bulk material must have been measured by methods that adequately account for void spaces (vugs, porosity, etc.), moisture and
differences between rock and alteration zones within the deposit.
|
• The Archimedes-principle method for density determination accounts for void spaces, moisture and differences in rock type.
|
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|
• Discuss assumptions for bulk density estimates used in the evaluation process of the different materials.
|
• Density values were assigned for all geological units in the model, including mineralized units as well as overburden, interburden and underburden waste units. By-unit densities were assigned
in the grade block model based on the block geological unit code as follows:
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