Iamgold Reports Positive Results from Its 2019 Drilling Program at Monster Lake, Quebec

NEWS RELEASE

TSX: IMG NYSE: IAG

IAMGOLD REPORTS POSITIVE RESULTS FROM ITS 2019

DRILLING PROGRAM AT MONSTER LAKE, QUEBEC

Toronto, Ontario, July 23, 2019 – IAMGOLD Corporation (“IAMGOLD” or the “Company”) today

announced assay results from the 2019 winter drilling program completed at its Monster Lake joint venture

project (IAMGOLD Corporation: 50%, TomaGold Corporation: 50%), located 50 kilometres southwest of

Chibougamau, Quebec, Canada. The Company is reporting the final assay results from 16 drill holes,

totaling 5,270 metres, completed as part of the 2019 exploration program.

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

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

Annie Shear Zone system:

 Drill hole ML19-244: 0.8 metres grading 357.0 g/t Au

 Drill hole ML19-248: 6.8 metres grading 3.85 g/t Au

o Includes: 1.67 metres grading 6.43 g/t Au

 Drill hole ML19-249: 0.5 metres grading 133.0 g/t Au

Big Mama Shear Zone area:

 Drill hole ML19-245: 13.0 metres grading 2.27 g/t Au

o Includes: 1.39 metres grading 6.45 g/t Au

o Includes: 1.47 metres grading 7.65 g/t Au

The Monster Lake joint venture project hosts an NI 43-101 compliant resource, effective as at February 26,

2018, 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 19, 2019).

The objective of the 2019 drilling program was to test priority areas along the strike of the main structural

corridor, hosting the 325-Megane zone, for additional zones of mineralization with potential to increase

total mineral resources on the property. Three main target areas were tested along the Monster Lake

Mineralized Corridor and included: the southern extensions of the 325-Megane and Lower Shear zones;

the general area of the intersection of the Main Shear zone and the Big Mama Shear zone to the northeast

of the 325-Megane zone; and the Annie Shear zone system also to the northeast along strike of the 325-

Megance zone. All of the areas targeted in this program were best accessed during the winter when the

ground is frozen.

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

yielded positive results from the Big Mama and Annie areas, which included the intersection of some local

high grade intervals carrying visible gold. These positive results continue to demonstrate the potential for

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

Next Steps

These results will be incorporated into the structural and deposit model and used to guide the next

drilling programs. Ongoing field activities for the summer season includes geological, geochemical

and structural studies to support exploration targeting.

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About the Monster Lake Project

The Monster Lake project is underlain by Archean volcanic rocks of the Obatogamau Formation and is

traversed by an important deformation corridor and associated gold-bearing mineralized structures.

Historical drilling and exploration by TomaGold Corporation (“TomaGold’) have identified a four-kilometre

long structural corridor, along which most of the known gold occurrences discovered to date on the

property are associated, including the 325-Megane Zone.

The Monster Lake Project is held under an earn-in option to joint venture agreement with TomaGold. The

Company holds an undivided 50% interest in the property, and holds an option to earn a further 25%

undivided interest, for a total 75% undivided interest in the Project, should it spend a total of C$10.0 million

on the Project within a seven year period, beginning January 1, 2015. 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. Under the terms of the option agreement, IAMGOLD continues

to conduct exploration on the project with a view to increase its ownership to 75% .

On August 14, 2017, IAMGOLD subscribed for 27.7 million common shares of TomaGold from treasury

representing 19.98% of the outstanding common shares of TomaGold. The common shares were

purchased at a price of C$0.09 per common share, for an aggregate purchase price of C$2.5 million. Prior

to the acquisition, IAMGOLD did not hold any common shares of TomaGold.

Technical Information and Quality Control Notes

The drilling results contained in this news release have been prepared in accordance with National

Instrument 43-101 Standards of Disclosure for Mineral Projects ("NI 43-101").

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

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

Person" for the purposes of National Instrument 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.

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Forward Looking Statement

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

(including, without limitation, statements regarding expected, estimated or planned gold production, cash costs, margin

expansion, capital expenditures and exploration expenditures and statements regarding the estimation of mineral

resources, exploration results, potential mineralization, potential mineral resources and mineral reserves) are forward-

looking statements. Forward-looking statements are generally identifiable by use of the words “will”, “should”,

“continue”, “expect”, “anticipate”, “estimate”, “believe”, “intend”, “to earn”, “to have’, “plan” or “project” or the negative of

these words or other variations on these words or comparable terminology. 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 differ materially from those discussed in the 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 planned gold production, cash costs, margin

expansion, capital expenditures and exploration expenditures and failure to establish estimated mineral resources, 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 provincial securities regulatory authorities. Any

forward-looking statement speaks only as of the 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.

About IAMGOLD

IAMGOLD ( www.iamgold.com) is a mid -tier mining company with four operating gold mines on three

continents. A solid base of strategic assets in North and South America and West Africa is complemented

by development and exploration projects and continued assessment of accretive acq uisition opportunities.

IAMGOLD is in a strong financial position with extensive management and operational expertise.

For further information please contact:

Indi Gopinathan, Investor Relations Lead, IAMGOLD Corporation

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

Martin Dumont, 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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Table 1: Monster Lake Project Drilling Results - 2019 Drilling Program

Notes:

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

2. True widths of intersections are approximately 50 to 80% 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-19-235 519,967 5,488,171 369.36 290 -60 343.0 215.00 215.70 0.70 0.54 1.25 Main Shear Zone

ML-19-236 519,903 5,488,130 368.96 295 -55 316.0 41.50 42.30 0.80 0.61 1.77 E-W Shear Zone

146.00 149.20 3.20 2.45 1.03 Main Shear Zone

ML-19-237 520,066 5,488,047 372.27 285 -55 520.0 333.43 338.00 4.57 3.50 1.39 Main Shear Zone

ML-19-238 519,862 5,488,089 368.82 300 -50 241.0 211.55 212.55 1.00 0.77 1.84 Low er Shear Zone

ML-19-239 519,892 5,487,962 369.28 305 -45 301.0 168.30 173.25 4.95 3.79 1.26 Main Shear Zone

ML-19-240 519,797 5,488,794 371.46 310 -50 170.0

ML-19-241 519,826 5,488,800 372.85 310 -50 224.0

ML-19-242 519,878 5,488,830 373.46 310 -50 250.0

ML-19-243 520,187 5,488,837 371.86 310 -60 356.0 128.00 132.50 4.50 2.58 1.88 Big Mama Shear Zone

ML-19-244 520,938 5,489,826 373.58 330 -60 409.0 182.20 183.00 0.80 0.51 357 Annie - Secondary Shear Zone

245.30 246.00 0.70 0.45 2.77 Annie Shear Zone

255.00 256.00 1.00 0.64 1.08

ML-19-245 520,202 5,488,856 371.96 320 -48 365.5 155.08 168.11 13.03 7.47 2.27 Big Mama Shear Zone

Including (3) 155.08 156.47 1.39 0.80 6.45

Including (3) 166.64 168.11 1.47 0.84 7.65

219.40 221.35 1.95 1.49 1.20 Main Shear Zone

ML-19-246 520,417 5,488,812 372.33 315 -45 494.0 392.10 393.85 1.75 1.34 5.27 Secondary Shear Zone

417.83 422.15 4.32 3.31 1.61 Main Shear Zone

Including (3) 417.83 418.75 0.92 0.70 4.08

ML-19-247 520,744 5,489,618 376.16 330 -65 262.0

ML-19-248 520,714 5,489,432 377.29 315 -50 305.0 255.90 262.70 6.80 4.37 3.85 Annie Shear Zone

Including (3) 259.00 260.67 1.67 1.07 6.43

ML-19-249 520,462 5,489,231 374.15 329 -58 349.0 196.50 197.00 0.50 0.25 133 Annie - Secondary Shear Zone

210.40 210.90 0.50 0.25 4.40 Annie - Secondary Shear Zone

292.28 298.21 5.93 2.97 0.75 Annie Shear Zone

302.53 306.44 3.91 1.96 1.78

ML-19-250 520,621 5,489,264 375.78 335 -50 364.0 330.30 335.00 4.70 2.35 0.57 Annie Shear Zone

342.50 343.85 1.35 0.68 5.51 Annie Shear Zone

347.50 349.75 2.25 1.13 1.71 Annie Shear Zone

No significant results

UTM NAD83 Zone18

No significant results

No significant results

No significant results

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