IAMGOLD Reports Further High Grade Drill Intersections at Its Diakha Deposit, Siribaya Project in Mali

TORONTO, Oct. 18, 2018 - IAMGold Corp. ("IAMGOLD" or the "Company") today provided results from its 2018 drilling program at the Diakha deposit on its wholly owned Siribaya Project in Western Mali.  In 2018, the Company completed a combined diamond and Reverse Circulation ("RC") drilling program designed to infill and increase confidence in the current resource as well as target expansions of the Diakha deposit to support an updated resource estimate.  Assay results are reported herein for 100 drill holes totaling 14,634 metres.

Assay intersections relating to this release are provided in Tables 1 and 2, and include the following highlights: (a drill hole plan map is attached to this news release.)

Craig MacDougall, Senior Vice President, Exploration for IAMGOLD, stated, "We continue to be very pleased with the results of our delineation drilling programs,  which confirm not only wide zones of mineralization and locally high grades from infill holes within the existing resource, but also well mineralized intervals beyond the original resource limits.  The deposit now extends for nearly 3 kilometres along strike, which we believe will positively impact an updated resource estimate due for completion by year end."

About the Siribaya Project

The Siribaya project is wholly owned by IAMGOLD and consists of 8 contiguous exploration permits which cover a total area of 596.5 square kilometres, located in the Kédougou-Kéniéba inlier of the West African Craton region of western Mali along the borders with Senegal and Guinea. 

The project hosts current mineral resources comprising indicated resources of 2.1 million tonnes averaging 1.90 grams of gold per tonne for 129,000 ounces and inferred resources of 19.8 million tonnes averaging 1.71 grams of gold per tonne for 1.1 million ounces (see news release dated February 12, 2018). 

Gold mineralization is hosted within highly prospective, Birimian-aged metasedimentary, volcanic and intrusive rocks proximal to the Senegal-Mali Shear Zone. At Diakha, the largest deposit discovered to date, gold mineralization occurs within an albitized sandstone unit similar to that hosting IAMGOLD's Boto gold deposit located in Senegal approximately 10 kilometres to the north along strike and for which a feasibility study is nearing completion.

Next Steps

The drilling results will be used to refine the deposit model to support an updated resource estimate expected by year end. Upon completion of the resource estimate, further drilling is anticipated in 2019 to continue to better define and expand resources at the Diakha deposit as well as explore other identified priority targets. 

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 sampling of, and assay data from, drill core and RC chips are monitored through the implementation of a quality assurance - quality control (QA-QC) program designed to follow industry best practice. Rock chips from Reverse Circulation drilling are collected at the rig site, at one metre intervals, under the direct supervision of IAMGOLD geologists and field technicians. Samples are riffle split to obtain two 3 kg samples.  One sample is retained for reference purposes and the other sample is sent for assay.

Drill core (HQ and NQ size) samples were selected by the IAMGOLD geologists and sawn in half with a diamond saw at the project site. Half of the core was retained at the site for reference purposes.  Drill core sample intervals are generally one metre in length.

The samples were assayed at the SGS Minerals Analytical Laboratory in Bamako, Mali, using a standard fire assay with a 50-gram charge and an Atomic Absorption finish (FAA505). All samples returning values greater than 10 g/t Au were re-assayed using a gravimetric finish (FAG505).

Qualified Persons

The information in this news release was prepared under the supervision of, and reviewed and verified by, Craig MacDougall, P.Geo., Senior Vice President, Exploration for IAMGOLD. Mr. MacDougall is a Qualified Person as defined by National Instrument 43-101.

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 "may", "will", "should", "continue", "expect", "anticipate", "estimate", "believe", "intend", "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 acquisition opportunities. IAMGOLD is in a strong financial position with extensive management and operational expertise.

For further information please contact:

Ken Chernin, VP Investor Relations, IAMGold Corp.
Tel: (416) 360-4743  Mobile: (416) 388-6883 

Laura Young, Director, Investor Relations, IAMGold Corp.
Tel: (416) 933-4952 Mobile: (416) 670-3815

Martin Dumont, Senior Analyst Investor Relations, IAMGold Corp.
Tel: (416) 933-5783 Mobile: (647) 967-9942

Toll-free: 1-888-464-9999  info@iamgold.com

Please note:
This entire news release may be accessed via fax, e-mail, IAMGOLD's website at www.iamgold.com and through CNW Group's website at www.newswire.ca. 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 http://www.iamgold.com/French/accueil/default.aspx.

Table 1: Diakha Deposit - 2018 Diamond Drilling Assay Results (36 DDH totaling 7,098 metres)

Table 2: Diakha Deposit - 2018 RC Drilling Assay Results (64 RC holes totaling 7,536 metres)