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Iamgold Intersects Mineralization Along Strike at Monster Lake, Quebec; Provides Results from 2020 Exploration Program

Drill Results Mine Development & Operations

NEWS RELEASE

TSX: IMG NYSE: IAG

IAMGOLD INTERSECTS MINERALIZATION ALONG STRIKE AT MONSTER LAKE, QUEBEC;

PROVIDES RESULTS FROM 2020 EXPLORATION PROGRAM

Toronto, Ontario, August 13, 2020 – IAMGOLD Corporation (“IAMGOLD” or the “Company”) today

announced assay results from the 2020 drilling program completed at its Monster Lake joint venture

project (IAMGOLD: 75%, TomaGold Corporation1: 25%), located 50 kilometres southwest of Chibougamau,

Quebec, Canada. The Company is reporting the final assay results from 6 drill holes, totaling 2,991

metres, completed as part of the 2020 exploration program.

The assay results are provided in Table 1 below and include the following highlights:

(A drill hole plan map and longitudinal section are attached to this news release.)

Annie Shear Zone system:

 Drill hole ML-20-253: 3.8 metres grading 16.9 g/t gold

o Includes: 1.03 metres grading 7.36 g/t gold

o Includes: 0.80 metres grading 66.50 g/t gold

 Drill hole ML-20-255: 4.0 metres grading 1.89 g/t gold

Big Mama Shear Zone:

 Drill hole ML-20-251: 2.82 metres grading 5.63 g/t gold

Main Shear Zone area:

 Drill hole ML-20-252: 12.3 metres grading 2.09 g/t gold

The Monster Lake joint venture project (on a 100% basis) hosts a Mineral Resource comprising 1,109,700

tonnes of inferred resources averaging 12.14 grams of gold per tonne for 433,300 ounces of contained

gold, assuming an underground mining scenario (see news releases dated March 28, 2018 and February

18, 2020), as prepared in accordance with National Instrument 43-101 (“NI 43-101”) Standard of

Disclosure for Mineral Projects.

The objective of the 2020 drilling program was to test priority areas along the strike of the main Monster

Lake structural corridor, which hosts the 325-Megane zone, for additional zones of mineralization with

potential to increase total mineral resources on the property. The focus was on testing the Annie Shear

Zone extending to the northeast along strike of the 325-Megane zone in an effort to extend the

mineralization intersected during 2019. The program was executed in two phases due to the suspension of

activities in March 2020, as directed by the Government of Quebec in response to the COVID-19 crisis.

The program was subsequently restarted, and completed in June 2020.

Craig MacDougall, Senior Vice President, Exploration for IAMGOLD, stated: “The drilling program

continues to intersect the targeted shear zones with further positive results from the Annie area. Our

increasing understanding of the complex structural context has highlighted several discrete parallel shear

zones hosting mineralization adjacent to the main known structural corridor. These results highlight the

1 JV Partners include TomaGold Corporation (“TomaGold” ) at 22.5% and Quinto Resources Inc. (“Quinto”) at 2.5%

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potential for the discovery of additional mineralized shoots along the Monster Lake structural corridor. ”

Next Steps

These drilling results will be incorporated into the structural and deposit models and used to guide

the next drilling programs. Ongoing field activities for the summer season includes geological and

geochemical surveys. Regional structural studies continue to support exploration targeting.

About the Monster Lake Project

The Monster Lake project is located 50 kilometres southwest of Chibougamau, Quebec, and is underlain

by Archean volcanic rocks of the Obatogamau Formation, which are traversed by an important deformation

corridor with associated gold-bearing mineralized structures. Exploration to date has traced this

prospective structural shear zone system for at least 4 kilometres along strike, along which several gold

prospects have been discovered and a Mineral Resource delineated at the 325-Megane Zone.

The Monster Lake Project is held under a joint venture agreement with TomaGold. The Company holds an

undivided 75% interest in the property after having fulfilled the terms of its second Earn-In at the end of

2019. Should a development decision be made by the joint venture, or should the joint venture declare

commercial production, TomaGold would be entitled to a further C$1.0 million payment.

Technical Information and Quality Control Notes

The drilling results contained in this news release have been prepared in accordance with NI 43-101

Standards of Disclosure for Mineral Projects.

The "Qualified Person" responsible for the supervision of the preparation and review of this information is

Marie-France Bugnon, P. Geo., General Manager Exploration. Marie-France is considered a "Qualified

Person" for the purposes of NI 43-101 with respect to the technical information being reported on. The

technical information has been included herein with the consent and prior review of the above noted

Qualified Person. The Qualified person has verified the data disclosed, and data underlying the information

or opinions contained herein.

The design of the drilling program and interpretation of results is under the control of IAMGOLD’s

geological staff, including qualified persons employing strict protocols consistent with NI 43-101 and

industry best practices. The sampling of, and assay data from, the drill core is monitored through the

implementation of a quality assurance - quality control (QA-QC) program. Drill core (NQ size) is logged

and samples are selected by the IAMGOLD geologists and sawn in half with a diamond saw at the project

site. Half of the core is retained at the site for reference purposes. Sample intervals may vary from half a

metre to one and a half metres in length depending on the geological observations.

Half-core samples are packaged and transported in sealed bags to ALS Minerals Laboratory (“ALS”)

located in Val-d’Or, Québec. Samples are coarse crushed to a -10 mesh and then a 1,000 gram split is

pulverized to 95% passing -150 mesh. ALS processes analytical pulps directly at their facilities located in

Val-d’Or which is ISO / IEC 17025 certified by the Standards Council of Canada. Samples are analyzed

using a standard fire assay with a 50 gram charge with an Atomic Absorption (AA) finish. For samples that

return assay values over 5.0 grams per tonne, another pulp is taken and fire assayed with a gravimetric

finish. Core samples showing visible gold or samples which have returned values greater than 10.0 grams

per tonne are re-analyzed by pulp metallic analysis. IAMGOLD inserts blanks and certified reference

standards in the sample sequence for quality control.

CAUTIONARY STATEMENT ON FORWARD-LOOKING INFORMATION

This news release contains forward -looking statements. All statements, other than of historical fact, that address activities,

events or developments that the Company believes, expects or anticipates will or may occur in the future are forward -looking

statements. Forward-looking statements are generally identifiable by use o f the words “may”, “will”, “should”, “continue”,

“expect”, “anticipate”, “estimate”, “believe”, “prospective”, “significant”, “significant potential”, “substantial”, transfor mative”,

“intend”, “plan” or “project” or the negative of these words or other var iations on these words or comparable terminology.

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Forward-looking statements are subject to a number of risks and uncertainties, many of which are beyond the Company’s

ability to control or predict, that may cause the actual results of the Company to diffe r materially from those discussed in t he

forward-looking statements. Factors that could cause actual results or events to differ materially from current expectations

include, among other things, without limitation, failure to meet expected, estimated or pl anned gold production, unexpected

increases in all-in sustaining costs or other costs, unexpected increases in capital expenditures and exploration expenditures,

variation in the mineral content within the material identified as Mineral Resources and Miner al Reserves from that predicted,

changes in development or mining plans due to changes in logistical, technical or other factors, the possibility that future

exploration results will not be consistent with the Company's expectations, changes in world gold markets and other risks

disclosed in IAMGOLD’s most recent Form 40 -F/Annual Information Form on file with the United States Securities and

Exchange Commission and Canadian securities regulatory authorities. Any forward -looking statement speaks only as of t he

date on which it is made and, except as may be required by applicable securities laws, the Company disclaims any intent or

obligation to update any forward -looking statement. The Company disclaims any intention or obligation to update or revise

any forward-looking statements whether as a result of new information, future events or otherwise except as required by

applicable law.

About IAMGOLD

IAMGOLD is a mid-tier mining company with three gold mines on three continents, including the Essakane

mine in Burkina Faso, the Rosebel mine in Suriname, and the Westwood mine in Canada. A solid base of

strategic assets is complemented by the Côté Gold development project in Canada, the Boto Gold

development project in Senegal, as well as greenfield and b rownfield exploration projects in various

countries located in West Africa and the Americas. On July 21, 2020, the Company, together with joint

venture partner Sumitomo Metal Mining Co. Ltd., announced the decision to proceed with the construction

of the Côté Gold Project.

IAMGOLD is committed to maintaining its culture of accountable mining through high standards of ESG

practices and employs approximately 5,000 people. IAMGOLD’s commitment is to Zero Harm, in every

aspect of its business. IAMGOLD is one of the companies on the JSI index.

IAMGOLD is listed on the Toronto Stock Exchange (trading symbol “IMG”) and the New York Stock

Exchange (trading symbol “IAG”).

For further information please contact:

Indi Gopinathan, VP, Investor Relations & Corporate Communications, IAMGOLD Corporation

Tel: (416) 360-4743 Mobile: (416) 388-6883

Philip Rabenok, Senior Analyst, Investor Relations, IAMGOLD Corporation

Tel: (416) 933-5783 Mobile: (647) 967-9942

Toll-free: 1-888-464-9999 [email protected]

Please note:

This entire news release may be accessed via fax, e -mail, IAMGOLD's website at www.iamgold.com and through Newsfile’s website

at www.newsfilecorp.com. All material information on IAMGOLD can be found at www.sedar.com or at www.sec.gov.

Si vous désirez obtenir la version française de ce communiqué, veuillez consulter le www.iamgold.com/French/Home/default.aspx .

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Notes:

1. Drill hole intercepts are calculated using a 0.50 g/t Au assay cut-off.

2. True widths of intersections are approximately 60 to 84% of the core interval.

3. Assays are reported uncut but high grade sub -intervals are highlighted.

Hole No. AZ DIP EOH From To Interval True Width

(2) Au (1) (3) NOTE

Easting Northing Elevation (°) (°) (m) (m) (m) (m) (m) (g/t)  

ML-20-251 520260 5488855 373 325 -50 549.0 238.88 241.70 2.82 1.81 5.63 Big Mama Shear Zone

326.00 327.00 1.00 0.57 3.50 Monster Lake Shear Zone

ML-20-252 520405 5489142 373 315 -60 498.0 235.25 236.00 0.75 0.57 4.84 Annie - Secondary Shear Zone (02)

275.45 276.90 1.45 1.11 2.69 Annie - Secondary Shear Zone (03)

341.70 354.00 12.30 9.42 2.09 Main Shear Zone

Including (3) 350.50 353.35 2.85 2.18 4.52

ML-20-253 520638 5489191 375 315 -50 474.0 341.30 345.10 3.80 2.91 16.89 Annie - Secondary Shear Zone (02)

Including (3) 342.40 343.43 1.03 0.79 7.36

Including (3) 344.30 345.10 0.80 0.61 66.50

408.70 411.00 2.30 1.76 1.03 Annie Shear Zone

425.00 426.00 1.00 0.77 2.49

ML-20-254 520719 5489428 378 320 -58 402.0 No significant results

ML-20-255 520625 5489264 376 320 -58 504.0 301.10 303.40 2.30 1.95 2.36 Annie - Secondary Shear Zone (02)

408.20 412.20 4.00 3.39 1.89 Annie Shear Zone

ML-20-256 521025 5489790 373 330 -55 474.0 351.00 357.00 6.00 4.60 0.73 Annie Shear Zone

ML-20-256A 521025 5489790 373 330 -55 90.0 Abandonned due to excessive drill hole deviation

2991.0

Table 1 Monster Lake Project Drilling Results - 2020 Drilling Program

UTM NAD83 Zone18

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