Northern Star Resources : KCGM Mill Optimisation PFS Presentation

KCGM Mill Optimisation

Pre-Feasibility Study Update

June 2022

Forward Looking Statements, Reserves and Resources

Forward Looking Statements

Northern Star Resources Limited has prepared this announcement based on information available to it. No representation or warranty, express or implied, is made as to the fairness, accuracy, completeness or correctness of the information, opinions and conclusions contained in this announcement. To the maximum extent permitted by law, none of Northern Star Resources Limited, its directors, employees or agents, advisers, nor any other person accepts any liability, including, without limitation, any liability arising from fault or negligence on the part of any of them or any other person, for any loss arising from the use of this announcement or its contents or otherwise arising in connection with it.

This announcement is not an offer, invitation, solicitation or other recommendation with respect to the subscription for, purchase or sale of any security, and neither this announcement nor anything in it shall form the basis of any contract or commitment whatsoever.

This announcement may contain forward looking statements that are subject to risk factors associated with gold exploration, mining and production businesses. It is believed that the expectations reflected in these statements are reasonable but they may be affected by a variety of variables and changes in underlying assumptions which could cause actual results or trends to differ materially, including but not limited to price fluctuations, actual demand, currency fluctuations, drilling and production results, Resource or Reserve estimations, loss of market, industry competition, environmental risks, physical risks, legislative, fiscal and regulatory changes, economic and financial market conditions in various countries and regions, political risks, project delay or advancement, approvals and cost estimates.

ASX Listing Rules Disclosures

This announcement contains current estimates of Northern Star's KCGM Operations' Ore Reserves and Mineral Resources. The information in this announcement that relates to the current Ore Reserves and Mineral Resources, and production targets of Northern Star has been extracted from the ASX release by Northern Star entitled "Resources, Reserves and Exploration Update" dated 3 May 2022 available at www.nsrltd.comand www.asx.com("Northern Star Announcement").

Northern Star confirms that it is not aware of any new information or data that materially affects the information included in the Northern Star Announcement other than changes due to normal mining depletion during the three month period to 28 June 2022, and, in relation to the estimates of Northern Star's KCGM Operations' Ore Reserves and Mineral Resources, that all material assumptions and technical parameters underpinning the estimates in the Northern Star Announcement continue to apply and have not materially changed. Northern Star confirms that the form and context in which the Competent Person's findings are presented have not been materially modified from that announcement.

Assumptions made in relation to the Ore Reserves and Mineral Resources underpinning the production targets in that announcement are (in summary):

• Current operational capital and operating cost structures,
• Current mining and metallurgical performance,
• The gold price, exchange rate, dilution allowance and mining recovery rates are as set out in each prior public report referred to in ASX Listing Rule 5.19 disclosures, and
• 5 year gold production profiles are based on 100% current JORC compliant Ore Reserves.

Rounding is applied in this presentation for the percentage comparisons and for the 31 March 2022 Ore Reserves and Mineral Resources figures.
Unless stated otherwise, all currency conversions in this document have been converted at a currency of A$/US$ conversion rate of $0.75.
Authorised to release to the ASX by Stuart Tonkin, Managing Director & CEO.	2

Presentation team

Stuart Tonkin

Managing Director & CEO

Mr Tonkin is a mining engineer with more than 25 years' experience working in the underground hard-rock mining industry. He joined Northern Star as Chief Operating Officer in 2013 before being appointed CEO in 2016 and Managing Director in 2021.

Ryan Gurner

Chief Financial Officer

Mr Gurner is a Chartered Accountant with extensive global financial and commercial experience spanning over 20 years. He was re-appointed Chief Financial Officer in December 2021, a position he held prior to the merger with Saracen Mineral Holdings.

Steven McClare

Chief Technical Officer

Mr McClare is a mining engineer with over 30 years of technical, operational and project experience in the mining industry. His extensive career includes building multi-billion dollar caving projects and bringing mines from design through to production. He joined Northern Star as Chief Technical Officer in July 2021.

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World class gold assets in Tier-1 locations

Our Purpose

To generate superior returns for our shareholders,

while providing positive benefits for our stakeholders, through operational effectiveness, exploration and active portfolio management

1	2	3
Commodity	Countries	Production
Centres

Pogo

7.3Moz Resource 1.8Moz Reserve

Yandal

9.8Moz Resource 3.9Moz Reserve

Kalgoorlie

37.1Moz Resource

14.9Moz Reserve

Perth

Australia

US

(Alaska)

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KCGM: One of the world's most significant gold mines

• A Tier-1world-class gold operating asset; 100% ownership
• Ranked Top 8 globally by Reserve*
  (27.4Moz Mineral Resource & 11.9Moz Ore Reserve)
• 297km2 of tenure, hosting +30km of the Boulder-Lefroy structural corridor
• Produced +65Moz gold since first production in 1893
• On track to deliver 650kozpa by FY26

Moz	Reserve Base of Global Operating Assets

50

40

30

20

10

0

Muruntau*

Nevada JV*

South Deep*

Lihir

Olimpiada

Cadia

Detour Lake*

KCGM

Boddington*

Blagodatnoye

Kyzyl

Ahafo*

Asset Reserves are reported in accordance with the JORC Code 2012, unless otherwise notated by an asterisk.	5
* Nevada JV, Boddington, Ahafo Reserves have been prepared in accordance with the new Regulation S-K 1300 requirements; Detour Lake Reserves prepared in accordance with the National Instrument 43-101 Standards of Disclosure for

Mineral Projects ("NI 43-101"); South Deep Reserves prepared in accordance with the South African code for the Reporting of Exploration Results, Mineral Resources and Mineral Reserves, 2016 edition (SAMREC Code); Muruntau Reserves prepared in accordance with the former Soviet system for classification of Mineral Resources & Reserves.