Alumina : Alcoa Third Quarter 2017 Earnings Release

ASX Announcement 19 October 2017

Alumina Limited (ASX: AWC) notes Alcoa Corp's ("Alcoa") quarterly earnings release. To assist readers in understanding relevant market, operational and commercial matters of the AWAC joint venture, selected information from the Alcoa Bauxite and Alumina Segment results and other market data are attached.

Alumina Limited's CEO, Mike Ferraro, commented, "The adjusted EBITDA for Alcoa's total bauxite and alumina businesses in the third quarter totalled US$316 million. Over the same period, the average one-month lagged alumina spot price was US$309 per tonne. We expect that the significantly higher spot alumina prices reported since late August should be reflected in the fourth quarter results." The spot alumina price as at 17 October 2017 was approximately US$476 per tonne.

In 3Q 2017 AWAC's production of alumina was 3.1 million tonnes and bauxite production from wholly owned mines and equity interests was 11.0 million bone dry tonnes.

From 1 January 2017 to today, Alumina Limited has received US$272.3 million of dividends, distributions and capital returns from AWAC, of which US$56.0 million was contributed back to AWAC entities. Therefore, net receipts from AWAC for the same period were US$216.3 million, of which US$50.2 million and US$132.6 million were included in the calculation of the 2016 final dividend and the 2017 interim dividend, respectively.

Alumina Limited's net debt was approximately US$127.6 million at the end of September 2017.

About AWAC & Alcoa's Earnings Release

Alumina Limited owns 40% of each of the AWAC entities, which form a part of the Alcoa bauxite & alumina business segments. The Alcoa aluminium business segment includes the AWAC Point Henry smelting (closed 1 August 2014) and Portland smelting operations. The Afobaka power station and Anglesea power station operations (closed 31 August 2015) are included in Transformation & legacy pension/OPEB. Therefore, the AWAC results cannot be directly inferred from the Alcoa earnings release. Further, unlike Alumina Limited, Alcoa reports under US GAAP. All figures displayed are in US dollars unless otherwise shown.

Forward-looking statements

Neither Alumina nor any other person warrants or guarantees the future performance of Alumina or any return on any investment made in Alumina securities. This document may contain certain forward-looking statements, including forward-looking statements within the meaning of the US Private Securities Litigation Reform Act of 1995. The words "anticipate", "aim", "believe", "expect", "project", "estimate", "forecast", "intend", "likely", "should", "could", "will", "may", "target", "plan" and other similar expressions (including indications of "objectives") are intended to identify forward-looking statements. Indications of, and guidance on, future financial position and performance and distributions, and statements regarding Alumina's future developments and the market outlook, are also forward- looking statements.

Any forward-looking statements contained in this document are not guarantees of future performance. Such forward-looking statements involve known and unknown risks, uncertainties and other factors, many of which are beyond the control of Alumina and its directors, officers, employees and agents that may cause actual results to differ materially from those expressed or implied in such statements.

Those risks, uncertainties and other factors include (without limitation): (a) material adverse changes in global economic conditions, alumina or aluminium industry conditions or the markets served by AWAC; (b) changes in production or development costs, production levels or sales agreements; (c) changes in laws, regulations or policies; (d) changes in alumina or aluminium prices or currency exchange rates; (e) Alumina Limited does not hold a majority interest in AWAC and decisions made by majority vote may not be in the best interests of Alumina Limited; and (f) the other risk factors summarised in Alumina's Annual Report 2016. Readers should not place undue reliance on forward-looking statements. Except as required by law, Alumina disclaims any responsibility to update or revise any forward-looking statements to reflect any new information or any change in the events, conditions or circumstances on which a statement is based or to which it relates.

Colin Hendry

Assistant Company Secretary

For investor enquiries: For media enquiries:

Chris Thiris Charles Smitheram Tim Duncan

Chief Financial Officer Manager - Treasury & Investor Relations Hinton and Associates Phone: +61 3 8699 2607 Phone: +61 3 8699 2613 Phone: +61 3 9600 1979

chris.thiris@aluminalimited.com charles.smitheram@aluminalimited.com Mobile: +61 408 441 122

• Alcoa Corp's 3Q 2017 Bauxite and Alumina Segments highlights
• Market data on commodity prices

19 October 2017

Summary Information

This Presentation contains summary information about the current activities of Alumina Limited (ACN 004 820 419) (Alumina) and its subsidiaries as at the date of this Presentation. The information in this Presentation should not be considered to be comprehensive nor to comprise all the information that a reader may require in order to make an investment decision regarding Alumina securities. This Presentation should be read in conjunction with Alumina's other periodic and continuous disclosure announcements lodged with the ASX, which are available at www.asx.com.au.

No Offer, Recommendation or Advice

This Presentation is for information purposes only and is not a prospectus, product disclosure statement or other disclosure or offering document under Australian or any other law. It does not constitute an offer, invitation or recommendation to acquire Alumina securities in any jurisdiction and neither this Presentation nor anything contained in it will form the basis of any contract or commitment.

The information contained in this Presentation is not financial product advice, or any other advice, and has been prepared without taking into account any reader's investment objectives, financial circumstances or particular needs.

Forward-Looking Statements

Neither Alumina nor any other person warrants or guarantees the future performance of Alumina or any return on any investment made in Alumina securities. This Presentation may contain certain forward-looking statements, including forward-looking statements within the meaning of the US Private Securities Litigation Reform Act of 1995. The words "anticipate", "aim", "believe", "expect", "project", "estimate", "forecast", "intend", "likely", "should", "could", "will", "may", "target", "plan" and other similar expressions (including indications of "objectives") are intended to identify forward-looking statements. Indications of, and guidance on, future financial position and performance and distributions, and statements regarding Alumina's future developments and the market outlook, are also forward-looking statements.

Any forward-looking statements contained in this document are not guarantees of future performance. Such forward-looking statements involve known and unknown risks, uncertainties and other factors, many of which are beyond the control of Alumina and its directors, officers, employees and agents that may cause actual results to differ materially from those expressed or implied in such statements. Those risks, uncertainties and other factors include (without limitation): (a) material adverse changes in global economic conditions, alumina or aluminium industry conditions or the markets served by AWAC; (b) changes in production or development costs, production levels or sales agreements; (c) changes in laws, regulations or policies; (d) changes in alumina or aluminium prices or currency exchange rates; (e) Alumina Limited does not hold a majority interest in AWAC and decisions made by majority vote may not be in the best interests of Alumina Limited; and (f) the other risk factors summarised in Alumina's Annual Report 2016. Readers should not place undue reliance on forward-looking statements. Except as required by law, Alumina disclaims any responsibility to update or revise any forward-looking statements to reflect any new information or any change in the events, conditions or circumstances on which a statement is based or to which it relates.

Key Risks

Certain key risks that may affect Alumina, its financial and operating performance and the accuracy of any forward-looking statements contained in this Presentation include (without limitation):

(a) material adverse changes in global economic conditions, alumina or aluminium industry conditions or the markets served by AWAC; (b) changes in production or development costs, production levels or sales agreements; (c) changes in laws, regulations or policies; (d) changes in alumina or aluminium prices or currency exchange rates; (e) Alumina Limited does not hold a majority interest in AWAC and decisions made by majority vote may not be in the best interests of Alumina Limited; and (f) the other risk factors summarised in Alumina's Annual Report 2016.

Past Performance

Past performance information contained in this Presentation is given for illustrative purposes only and should not be relied upon as (and is not) an indication of future performance.

No Liability

The information contained in this Presentation has been prepared in good faith and with due care but no representation or warranty, express or implied, is provided as to the currency, accuracy, reliability or completeness of that information.

To the maximum extent permitted by law, Alumina and its directors, officers, employees and agents, and any other person involved in the preparation of this Presentation, exclude and disclaim all liability for any expenses, losses or costs incurred by any person arising out of or in connection with the information contained in this Presentation being inaccurate or incomplete in any way for any reason, whether by negligence or otherwise.

2

Important Notes:

• Numerical information above is sourced from, and should be read in conjunction with, Alcoa Corp's quarterly earnings releases and presentations and relates to the Alcoa Corp Bauxite and Alumina Segments.

• The Alcoa Corp Bauxite and Alumina Segments include mining and refining operations at Pocos de Caldas, an additional 15% interest in the Sao Luis refinery and an additional interest in MRN which are not part of AWAC. AWAC accounted for 3.1 mt of the 3.3 mt of alumina produced by the Alcoa Corp Alumina Segment in 3Q 2017. AWAC's interest in the Portland smelter is included in the Alcoa Corp Aluminum Segment and the interest in Afobaka hydro-electric station is included in Transformation & legacy pension/OPEB.

• Adjusted EBITDA is a non-GAAP financial measure derived from Alcoa's consolidated financial information. Alcoa Corp's financial statements are prepared in accordance with US GAAP. The definition of Adjusted EBITDA and reconciliations to the most directly comparable GAAP financial measure can be found in the schedules to Alcoa Corp's earnings release.

Sources: Alcoa Corp 3Q 2017 Results Announcements and 3Q 2017 Earnings Conference presentations

Commodity prices in this slide pack are based on published market prices and may not equate to actual pricing under AWAC contracts 3