Iamgold Reports Results from Its 2019 Drilling Program ON the New Gosselin GOLD Zone – Côté GOLD Project, Ontario

NEWS RELEASE TSX: IMG NYSE: IAG

IAMGOLD REPORTS RESULTS FROM ITS 2019 DRILLING PROGRAM

ON THE NEW GOSSELIN GOLD ZONE – CÔTÉ GOLD PROJECT, ONTARIO

Toronto, Ontario, July 30, 2019 – IAMGOLD Corporation (“IAMGOLD” or the “Company”) today

provided assay results from its 2019 diamond drilling program at the previously announced Gosselin Zone

discovery (see news release dated March 26, 2019). The Gosselin Zone exploration program is part of the

Côté Gold Joint Venture Project, a 70:30 joint venture between IAMGOLD Corporation and Sumitomo

Metal Mining Co. Ltd (SMM Gold Côté Inc.), located 125 km southwest of Timmins and 175 km north of

Sudbury, Ontario, Canada.

During the 2019 drilling program, 14 NQ-sized diamond drill holes were completed for a total of 4,848

metres drilled. Thirteen (13) holes were completed from platforms established on the lake ice of Three

Ducks Lake and one (1) hole was land-based, drilled from a peninsula extending into the west central part

of Three Ducks Lake. One (1) hole was abandoned and re-collared due to drill hole deviation.

The assay results reported herein are provided in Table 1, below, and include the following highlights (see

plan map attached to this news release):

Gosselin Zone:

 Drill hole GOS19-17: 342.5 metres grading 0.98 g/t Au

includes: 225.0 metres grading 1.34 g/t Au

includes: 1.05 metres grading 110.0 g/t Au

 Drill hole GOS19-20: 134.0 metres grading 1.10 g/t Au

includes: 35.5 metres grading 1.92 g/t Au

 Drill hole GOS19-23: 248.3 metres grading 1.33 g/t Au

includes: 1.0 metre grading 168.0 g/t Au

 Drill hole GOS19-24: 412.0 metres grading 1.28 g/t Au

includes: 221.4 metres grading 1.47 g/t Au

includes: 1.06 metres grading 95.0 g/t Au

 Drill hole GOS19-27: 245.0 metres grading 0.85 g/t Au

includes: 1.0 metre grading 31.8 g/t Au

Craig MacDougall, Senior Vice President, Exploration for IAMGOLD, stated: “The results from the 2019

exploration program continue to confirm the potential of the new Gosselin discovery. We are particularly

encouraged by the continued intersection of wide intervals of intrusion-hosted mineralization, now

confirmed to extend to near surface as well as along strike to the southwest towards the Young-Shannon

zone. These results will be used to help design future drilling campaigns aimed at further evaluating the

resource potential of this new discovery.”

The 2019 diamond drilling program was designed to evaluate the resource potential by testing the near-

surface extension of the Gosselin Zone immediately beneath Three Ducks Lake, as well as evaluate the

continuity of mineralization between the Gosselin Zone and the recently recognized intrusion -hosted

mineralization associated with the historic Young-Shannon vein system.

The drilling program successfully confirmed both the near-surface extension beneath Three Ducks Lake

and mineralized continuity towards Young-Shannon. Eight drill holes returned wide mineralized intervals

starting at the bedrock–lake bottom interface and, along strike to the southwest, three drill holes (GOS19-

24, GOS19-28 and GOS19-29) returned significant mineralization in close proximity to the Young-Shannon

Gold Zone (refer to results from drill holes YS89-110, YS89-116, and YS89-181 reported in the March 26,

2019 News Release). Additional drilling is required to fully delineate the extent of the Gosselin discovery

and support a maiden resource estimate.

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Next Steps

The 2019 drill results, together with additional ICP analyses will be incorporated into a preliminary geologic

model for the Gosselin and Young-Shannon zones. In addition, a summer field program consisting of

mapping and surface channel sampling is underway which will further support the development and

refinement of the geologic model, which when completed, will be used to guide future drilling campaigns

with the goal of completing an initial resource estimate in the future.

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.

The "Qualified Person" responsible for the supervision of the preparation, verification and review of the

technical information in this release is Al Smith, P. Geo, District Manager – Exploration for IAMGOLD in

the Ontario Côte District. He is considered a "Qualified Person" for the purposes of National Instrument

43-101 with respect to the technical information being reported on. The "Qualified Person" responsible for

the planning, supervision and execution of the diamond drilling program is Brad McKinley, P. Geo, Senior

Geologist for IAMGOLD in the Ontario Côte District. The technical information has been included herein

with the consent and prior review of the above noted Qualified Persons.

The information in this news release was reviewed and approved by Craig MacDougall, P.Geo., Senior

Vice President, Exploration for IAMGOLD. Mr. MacDougall is a Qualified Person as defined by National

Instrument 43-101.

The sampling of, and assay data from, the drill core is monitored through the implementation of a quality

assurance - quality control (QA-QC) program designed to follow industry best practice. Drill core (NQ size)

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. Samples were stored in

sealed plastic bags and packed into fiber backs onto a pallet where they were shrink wrapped for

transport. A formal chain-of-custody procedure was adopted for security of samples until their delivery at

the laboratory.

Activation Laboratories Limited (ACTLABS - located in Timmins, Ontario) was utilized for assay analyses,

performing crushing, pulverizing, and fire assay in Timmins Ontario. Activation Laboratories completed the

following laboratory procedure: Samples are coarse crushed to 90% passing 2.0 mm screen (10 mesh

screen), riffle split (250 gram) and (mild steel) to 95% passing 105µm. Cleaner sand is included. Samples

were analyzed using a standard 30 gram fire assay (30 g aliquot) with an Atomic Absorption (AA) finish.

For samples that returned assay values over 3.0 grams per tonne (g/t), another cut is taken from the

original pulp and fire assayed with a gravimetric finish. For samples showing visible gold (VG) or samples

which have returned values greater than 5.0 g/t, these were re-analyzed by pulp metallic analysis.

IAMGOLD inserts blanks and certified reference standards in the sample sequence for quality control.

In accordance with recommendations from our on-going QA-QC program, additional check analyses are

underway at ACTLABS.

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 exploratio n 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 disclose d in IAMGOLD’s

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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 Relation 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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Notes:

1. Insufficient drilling has been completed to accurately determine the Gosselin Zone orientation. Actual core widths

are estimated at approximately 60 to 95% of the core interval.

2. Drill hole intercepts are calculated with a lower cut of 0.30 g/t Au.

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

Hole No. AZ DIP EOH From To Core Interval (1) Au (2)

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

GOS19-16A 430828 5267636 386 310 -55 300,0 220,0 264,0 44,0 0,31

GOS19-17 431183 5267780 390 340 -60 360,0 17,5 360,0 342,5 0,98

Including (3) 62,0 287,0 225,0 1,34

Including (3) 71,0 72,0 1,0 14,90

Including (3) 88,3 89,3 1,1 110,00

Including (3) 227,7 229,0 1,3 28,50

GOS19-18 431233 5267687 390 320 -70 351,0 57,1 108,0 50,9 8,08

Including (3) 103,0 104,0 1,0 395,00

168,0 196,0 28,0 0,35

243,0 305,0 62,0 0,33

GOS19-19 431158 5267670 389 330 -50 298,0 151,0 298,0 147,0 0,36

Including (3) 158,9 221,0 62,1 0,53

Including (3) 184,0 185,0 1,0 13,40

GOS19-20 431303 5267704 390 310 -45 300,0 164,0 298,0 134,0 1,10

Including (3) 184,0 298,0 114,0 1,25

Including (3) 189,5 225,0 35,5 1,92

GOS19-21 431297 5267803 390 330 -50 162,0 73,0 125,0 52,0 0,34

GOS19-22 431206 5267893 390 330 -50 309,0 135,0 145,0 10,1 0,35

GOS19-23 431132 5267770 389 335 -65 420,5 49,0 83,0 34,0 1,48

Including (3) 49,0 50,0 1,0 30,90

100,0 165,0 65,0 0,84

170,7 419,0 248,3 1,33

Including (3) 312,0 313,0 1,0 168,00

GOS19-24 431014 5267600 388 330 -65 428,0 16,0 428,0 412,0 1,28

Including (3) 34,0 255,4 221,4 1,47

Including (3) 121,0 122,1 1,1 95,00

Including (3) 207,4 208,5 1,1 11,30

Including (3) 283,7 428,0 144,3 1,30

Including (3) 331,0 331,7 0,7 10,80

Including (3) 408,5 409,5 1,0 10,70

GOS19-25 431074 5267759 389 330 -52 354,0 48,0 146,0 98,0 0,77

212,0 305,0 93,0 0,59

Including (3) 230,4 231,0 0,6 11,50

GOS19-26 431012 5267759 389 160 -65 368,3 101,0 145,0 44,0 1,40

Including (3) 102,0 103,0 1,0 17,20

Including (3) 128,0 129,0 1,0 13,00

Including (3) 129,0 130,0 1,0 12,90

174,0 249,0 75,0 1,11

Including (3) 184,8 186,0 1,3 11,60

260,0 344,0 84,0 0,44

GOS19-27 431067 5267672 389 330 -50 453,0 98,2 120,7 22,5 1,01

Including (3) 118,0 118,6 0,6 10,00

207,0 452,0 245,0 0,85

Including (3) 223,0 224,0 1,0 31,80

Including (3) 258,0 258,5 0,5 19,60

GOS19-28 430939 5267758 388 198 -50 339,0 12,5 28,5 16,0 0,37

210,0 281,0 71,0 0,64

296,0 326,9 30,9 0,69

GOS19-29 430882 5267552 391 95 -55 405,0 4,0 21,8 17,8 0,44

34,0 93,0 59,0 0,81

Including (3) 74,0 75,0 1,0 14,10

Table 1 Gosselin Project Drilling Results - 2019 Drilling program

UTM NAD83 Zone17

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Figure 1 – Gosselin Drill Hole Plan Map

GOS19-29

59.0 m grading 0.81 g/t Au

GOS19-26

44.0 m grading 1.40 g/t Au

75.0 m grading 1.11 g/t Au

84.0 m grading 0.44 g/t Au

GOS18-08CL15-39EXT

GOS18-09

GOS18-10

GOS18-11

GOS18-13

GOS18-12

GOS17-04

GOS17-05

GOS18-06

GOS18-07

GOS18-15A

GOS16-02GOS16-01

GOS17-03

GOS18-14

GOSSELIN PROJECT

2019 Drilling Program

YS87-8

YS88-47c

YS89-89

YS89-163

NV-02-03

YS90-182B

YS90-180

YS90-179

YS90-181

YS90-172B

YS89-82B

YS89-108B

YS89-110

YS89-116

Young-Shannon Shaft

GOS19-16A

GOS19-29

GOS19-20

GOS19-21

GOS19-22

GOS19-25

GOS19-17

GOS19-23

34.0 m grading 1.48 g/t Au

65.0 m grading 0.84 g/t Au

248.3 m grading 1.33 g/t Au

GOS19-23

GOS19-27

22.5 m grading 1.01 g/t Au

245.0 m grading 0.85 g/t Au

GOS19-19

LEGEND

2019 IAMGOLD drill holes

Previously reported drill holes

Historical drill holes

Lake

Modelled hydrothermal breccia

Estimated 0.5 g/t Au grade model

GOS19-27

GOS19-25

98.0 m grading 0.77 g/t Au

93.0 m grading 0.59 g/t Au

GOS19-24

412.0 m grading 1.28 g/t Au

Incl. 221.4 m grading 1.47 g/t Au

Incl. 144.33 m grading 1.30 g/t Au

GOS19-24

GOS19-26

GOS19-28

71.0 m grading 0.64 g/t Au

30.9 m grading 0.69 g/t Au

GOS19-28

YS90-183

GOS19-17

342.5 m grading 0.98 g/t Au

Incl. 225.0 m grading 1.34 g/t Au

GOS19-20

134.0 m grading 1.10 g/t Au

Incl. 114.0 m grading 1.25 g/t Au

Incl. 35.5 m grading 1.92 g/t Au

?

?

?

?

GOS19-18

50.9 m grading 8.08 g/t Au

Incl. 1.0 m grading 395 g/t Au

GOS19-18