Rhyolite Ridge American Source of Lithium & Boron for a Sustainable Future

James D. Calaway, Chairman of ioneer Ltd

Lithium Supply & Markets Conference

Santiago, Chile

June 2019

1

Important notices and disclaimers

This presentation has been prepared as a summary only and does not contain all information about ioneer Ltd’s (ioneer or the Company) assets and liabilities, financial position and performance, profits and losses, prospects, and the rights and liabilities attaching to ioneer’s securities. The securities issued by ioneer are considered speculative and there is no guarantee that they will make a return on the capital invested, that dividends will be paid on the shares or that there will be an increase in the value of the shares in the future.

ioneer does not purport to give financial or investment advice. No account has been taken of the objectives, financial situation or needs of any recipient of this presentation. Recipients of this presentation should carefully consider whether the securities issued by ioneer are an appropriate investment for them in light of their personal circumstances, including their financial and taxation position. Investors should make and rely upon their own enquiries before deciding to acquire or deal in the Company's securities.

Forward Looking Statements

Various statements in this presentation constitute statements relating to intentions, future acts and events which are generally classified as “forward looking statements”. These forward looking statements are not guarantees or predictions of future performance and involve known and unknown risks, uncertainties and other important factors (many of which are beyond the Company’s control) that could cause those future acts, events and circumstances to differ materially from what is presented or implicitly portrayed in this presentation.

For example, future reserves described in this presentation may be based, in part, on market prices that may vary significantly from current levels. These variations may materially affect the timing or feasibility of particular developments.

Words such as “anticipates”, “expects”, “intends”, “plans”, “believes”, “seeks”, “estimates”, “potential” and similar expressions are intended to identify forward-looking statements.

ioneer cautions security holders and prospective security holders to not place undue reliance on these forward-looking statements, which reflect the view of ioneer only as of the date of this presentation. The forward-looking statements made in this presentation relate only to events as of the date on which the statements are made. Except as required by applicable regulations or by law, ioneer does not undertake any obligation to publicly update or review any forward-looking statements, whether as a result of new information or future events. Past performance cannot be relied on as a guide to future performance.

Note: All $’s in this presentation are US$’s except where otherwise noted.

ASX: INR

Competent Persons Statement

The information in this presentation that relates to Exploration Results is based on information compiled by Bernard Rowe, a Competent Person who is a Member of the Australian Institute of Geoscientists. Bernard Rowe is a shareholder, employee and Managing Director of ioneer Ltd. Mr Rowe has sufficient experience that is relevant to the style of mineralisation and type of deposit under consideration and to the activity being undertaken to qualify as a Competent Person as defined in the 2012 Edition of the ‘Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves’. Bernard Rowe consents to the inclusion in the report of the matters based on his information in the form and context in which it appears.

In respect of Mineral Resources referred to in this presentation and previously reported by the Company in accordance with JORC Code 2012, the Company confirms that it is not aware of any new information or data that materially affects the information included in the public report titled “Updated Rhyolite Ridge Mineral Resource Statement” dated 23 October 2018 and released on ASX. Further information regarding the Mineral Resource estimate can be found in that report. All material assumptions and technical parameters underpinning the estimates in the report continue to apply and have not materially changed. The Company intends to report updated Mineral Resource and Ore Reserve estimates as part of the Definitive Feasibility Study currently in progress and due for completion in Q3 2019.

In respect of production targets referred to in this presentation and previously disclosed, the Company confirms that it is not aware of any new information or data that materially affects the information included in the public report titled “Outstanding Results from Rhyolite Ridge Pre-Feasibility” dated 23 October 2018. Further information regarding the production estimates can be found in that report. All material assumptions and technical parameters underpinning the estimates in the report continue to apply and have not materially changed.

No offer of securities

Nothing in this presentation should be construed as either an offer to sell or a solicitation of an offer to buy or sell ioneer securities in any jurisdiction, or be treated or relied upon as a recommendation or advice by ioneer.

Reliance on third party information

The views expressed in this presentation contain information that has been derived from publicly available sources that have not been independently verified. No representation or warranty is made as to the accuracy, completeness or reliability of the information. This presentation should not be relied upon as a recommendation or forecast by ioneer.

2

ASX: INR

is set to deliver a

major lithium-boron mine

in the USA

Boron differentiates Rhyolite Ridge 100% ownership of Rhyolite Ridge

lithium-boron searlesite resource

Fluor on-track to be complete DFS in

Q3 2019

Extensive process flowsheet testwork

completed by Kemetco and Veolia

Pilot plant commissioning underway and

will process one tonne per day

Environmental baseline studies near

complete

104Mt Indicated Resource with further

drilling completed to upgrade Reserve

Nevada location: major supplier of

critical material to North America

3

100%-owned Rhyolite Ridge:

• +30 year mine life, capable of producing:

• +20,000 tonnes p.a. lithium carbonate

• +170,000 tonnes p.a. boric acid

• Dual revenue stream

• Uniquely position to be a major supplier of

both products

• Forecast to be bottom of the lithium cost

curve due to revenue from boron co-product

ASX: INR

Rhyolite Ridge Lithium-Boron Project

Unique lithium-boron deposit where metals can be extracted using proven

commercial processes to produce lithium and boron end-products on site 4

Sedimentary lithium deposits are often incorrectly assumed to be synonymous with clay

There are two basic types of sedimentary lithium deposit: Lithium-Boron type and Clay type

Lithium-Boron deposits are mineralogically different to clay and this has major implications for ease and cost of processing

Rhyolite Ridge is one of only two known large Lithium-Boron deposits globally

Rhyolite Ridge ore is dominated (40-50%) by searlesite – a sodium boro-silicate mineral that is soluble in acid

Boron is a legitimate co-product providing 30-50% of revenue, into a global market that exceeds $3B annually

ioneer set to become third largest boron producer globally

Boron makes Rhyolite Ridge different to other sedimentary lithium deposits

High-grade searlesite Li-B mineralisation in outcrop

Boron is essential for a modern world

Boron is a larger market than lithium at ≈US$3.3 billion p.a.

Stable price and steady growth of 4-6% CAGR

Broad range of uses

Essential to modern life, often no substitutes

Duopoly:

Eti (Turkey) ≈50%

Rio (Boron, California) ≈30%

Rio’s Boron mine is an aging asset with finite mine life and limited potential for expansion

74% of global reserves located in Turkey

Major boron users also use lithium

Boron demand driven by:

Urbanisation

Energy efficiency

Agriculture

5

ASX: INR

Multiple options to fund US$600M in capex

Working with a top-tier international bank

Currently in the discovery phase

Engaging with interested parties on potential:

o Lithium and boron offtake

o Vendor and export credit finance

o Strategic partnering

Structured funding process in parallel with completion of

the DFS in Q3 2019

Two product streams

100% ownership of asset

Well positioned to assess and negotiate funding:

Large, scalable project provides optionality

Funded (~A$60M cash) to progress project to FID by early 2020

USA supplier of critical minerals

Funding flexibility & strategic partnering

6

Rhyolite Ridge progress

7

2016 2017 2018 2019 2020 2021

Resource and Reserve

upgrade

Lithium hydroxide

confirmed by Veolia

Pilot plant in operation

Fluor completes DFS

Testwork confirms high

vat leach recoveries &

premium boric acid

Initial Reserve

Positive, comprehensive

Pre-Feasibility Study

Positive met testwork

Drilling doubles

Resource

Rhyolite Ridge acquired

Initial Resource

Construction

planned

First production of

lithium and boron

from Rhyolite Ridge

Rhyolite Ridge video

8 ASX: INR

This video is available on the ioneer YouTube Channel

ASX: INR

Key partners

EPCM

Evaporation Acid Plant

Mining

Acid Plant

Leaching

Pilot Plant

Material

Handling

Controls

Environment

Spent Ore

Rhyolite Ridge product specifications

10

Compound or Element

Units

Rhyolite Ridge

Analysis

Typical Industry

Specifications

Lithium Hydroxide wt% 56.5 56.5

Sodium ppm 28 ≤ 30

Potassium ppm 12 ≤ 200

Iron ppm <1 ≤ 7

Boron ppm <1 ≤ 3

Calcium ppm <10 ≤ 250

Sulphate ppm <30 ≤ 300

Chlorine ppm <100 ≤ 100

Magnesium ppm <5 ≤ 5

Silica ppm 14 ≤ 20

Carbon Dioxide wt% 0.10 ≤ 0.35

Lithium Hydroxide Monohydrate Boric Acid

Chromium, nickel, copper, lead, aluminium and zinc all analysed <1ppm with typical industry specifications ranging from ≤5ppm to ≤10ppm.

Testwork and analysis were conducted by Veolia Water Technologies Inc. in Plainfield, Illinois, USA.

Compound or Element

Units Rhyolite Ridge

Analysis

Typical Industry

Specifications

Boric Oxide (B2O3) % >56.5 >56.25

Boric Acid (H3BO3) % >99.9 >99.9

Sulphate ppm <125 <250

Chloride ppm <1 <10

Iron ppm <5 <7

Calcium ppm 13 <50

Sodium ppm 43 <200

Chlorine ppm <5 <10

Lead ppm <10 <20

Arsenic ppm <10 <100

Testwork and analysis were conducted by Kemetco Research Inc. of Richmond, BC, Canada.

Yoshio Nagai Sales & Business Development ynagai@ioneer.com

James D. Calaway Chairman jcalaway@ioneer.com

Providing the materials for a sustainable &

thriving planet.

ASX: INR 11

12 ASX: INR

Looking south-east over Rhyolite Ridge South Basin

Nevada – Tier 1

Likely to benefit from the US Government’s renewed emphasis on domestic supplies of critical minerals

• Tier 1 Mining Jurisdiction

• Excellent infrastructure with direct access to rapidly expanding American and Asian markets

• Located on Federal (BLM) land

• No competing land uses or nearby residents

• Permitting to be via Environmental Assessment (EA) or an Environmental Impact Statement (EIS) as determined by Federal BLM

• Rhyolite Ridge likely to qualify for shorter EA process

• Net proceeds minerals tax not exceeding 5%

12

ASX: INR

• Total Resource1 of 4.1 million tonnes lithium carbonate & 10.9 million tonnes boric acid

• Including 121 million tonnes of lithium-boron ore containing: • 1.1 million tonnes lithium

carbonate • 8.6 million tonnes boric

acid • Lithium-only clay mineralisation to

be stockpiled

A searlesite resource that is different to other sedimentary lithium

deposits - it is suitable for a simple acid leach process

13 1 Indicated and Inferred Resource

Project Overview

ASX: INR Note: The PFS base case used lithium carbonate sale prices ranging from US$12,693/tonne to US$16,862/tonne (CIF China) and a constant boric acid sale price of US$700/tonne (CIF Asia).

Annual Revenue

$450M Annual EBITDA

$297M

After-tax Cashflow

$6.6B

After-tax NPV (7% real):

$1.8B

IRR

28%

Bottom of the Cost Curve

• $1,796 per tonne of lithium carbonate (with boric acid credit)

Lithium carbonate annual production = 20kt Boric acid annual production = 173kt

For every 1.0 tonne of lithium carbonate produced, 8.5 tonnes of boric acid is produced

Total Capex

$599M

PFS demonstrates robust project economics

14

Long Life Project

• >30 years & expandable

• Initial production Q3 2021

Lowest operating cost

Rhyolite Ridge to be at bottom of the lithium cost curve

ASX: INR

• Operating costs ~ $1,800/tonne lithium carbonate

(with boric acid credit)

• Boric acid revenue at $700/tonne pays for most of

site operating costs

Industry Lithium Carbonate Cost curve

• Acid plant provides all steam and power required

plus excess 38MW of green power for sale

• Ore leaches and washes well with overall lithium

and boron recoveries > 80%

15

On-site acid plant provides all of the steam and power required (+ circa 38MW surplus)

Ore crushed to 25mm

Ore vat leached at 50-60o C and at ambient pressure (similar to oxide copper)

Boric acid crystallised from solution (similar to Rio’s Boron Mine)

Lithium carbonate crystallised from solution (similar to lithium brines)

• Overall lithium and boron recoveries of >80%

• Very low cash costs due to:

• Simple process and high recoveries

• Exothermic nature of producing acid

• Boron revenue offsetting most of site costs

Using processing technologies proven at commercial scale

16 ASX: INR

Processing

16

17 ASX: INR

Processing flowsheet

17

Large 100%-owned mining claims

Sediment-hosted lithium-boron deposit

Similar mineralisation in two basins

Mineralisation outcrops over 3 km strike length

100% Federal (BLM) land

Lithium-Boron (Searlesite) Resource

121 Mt at 0.9% lithium carbonate, 7.1% boric acid contains:

1.1Mt lithium carbonate

8.7Mt boric acid

86% of resource in Indicated category

18 ASX: INR

District Scale Potential

18

13km

South Basin - Mineral Resource

outlined in blue

North Basin - 38 wide-spaced holes

with Li and B

ASX: INR For further information on this Mineral Resource estimate, see Company announcement titled

“Updated Rhyolite Ridge Mineral Resource Statement” dated 23 October 2018.

October 2018 Mineral Resource Estimate (1,050ppm Li Cut-off)

Total Resource including Lithium-Only Mineralisation and Lithium-Boron (Searlesite) Mineralisation

Group Classification Tonnage Li B Li2CO3 H3BO3 K2SO4 Li2CO3 Boric Acid Potassium

Mt ppm ppm % % % kt kt kt

Indicated 149.6 1,890 7,250 1.0 4.1 1.6 1,510 6,180 2,430

Inferred 49.4 1,860 4,300 1.0 2.4 1.6 490 1,200 770

Total 199.1 1,880 6,520 1.0 3.7 1.6 2,000 7,380 3,210

Indicated 192.4 1,370 2,880 0.7 1.6 1.6 1,410 3,060 3,020

Inferred 83.9 1,480 1,080 0.8 0.6 1.5 660 490 1,230

Total 276.3 1,410 2,340 0.7 1.3 1.5 2070 3,550 4,250

Indicated 342.0 1,600 4,800 0.9 2.7 1.6 2,910 9,240 5,450

Inferred 133.4 1,600 2,300 0.9 1.3 1.5 1,150 1,690 2,000

Grand Total 475.4 1,610 4,100 0.9 2.3 1.6 4,060 10,930 7,460

Contained

Upper Zone

Lower Zone

Upper &

Lower Zone

October 2018 Mineral Resource Estimate (1,050ppm Li & 0.5% B Cut-off Cut-off)

Lithium-Boron (Searlesite) Mineralisation

Group Classification Tonnage Li B Li2CO3 H3BO3 K2SO4 Li2CO3 Boric Acid Potassium

Mt ppm ppm % % % kt kt kt

Indicated 71.9 1,840 14,110 1.0 8.1 2.0 700 5,800 1,420

Inferred 14.7 1,970 12,150 1.0 6.9 2.0 150 1,020 300

Total 86.6 1,860 13,780 1.0 7.9 2.0 860 6,830 1,720

Indicated 32.2 1,430 9,750 0.8 5.4 1.7 240 1,730 530

Inferred 2.6 1,620 6,690 0.9 3.3 1.8 20 90 50

Total 34.8 1,440 9,520 0.8 5.2 1.7 270 1,820 580

Indicated 104.1 1,700 12,800 0.9 7.2 1.9 950 7,540 1,950

Inferred 17.3 1,900 11,300 1.0 6.4 2.0 180 1,110 340

Grand Total 121.4 1,740 12,600 0.9 7.1 1.9 1,130 8,650 2,300

Contained

Upper Zone

Lower Zone

Upper &

Lower Zone

19