IAMGOLD Reports High-grade Drill Intersections from its 2017 Drilling Program on the Diakha Deposit, Siribaya Project in Mali

TORONTO, Jan. 31, 2018 /PRNewswire/ - IAMGOLD Corporation ("IAMGOLD" or the "Company") today provided results from its 2017 drilling program at the Diakha deposit on its wholly owned Siribaya project in Western Mali.  In 2017, 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.  Assay results are reported herein for 105 drill holes totaling 19,520 metres.

Assay intersections relating to this release are provided in Tables 1 and 2, and include the following highlights:

Infill Drill Holes:

• SRD17-198: 26.0 metres grading 6.79 g/t Au
  Including: 8.0 metres grading 20.52 g/t Au
  
• SRD17-205: 18.0 metres grading 11.06 g/t Au
  Including: 6.0 metres grading 32.45 g/t Au
  
• SRD17-215: 13.0 metres grading 2.81 g/t Au
  and 26.0 metres grading 2.62 g/t Au

Expansion Drill Holes:

• SRD17-217: 16.0 metres grading 4.70 g/t Au
  Including: 4.0 metres grading 16.11 g/t Au
  
• SRD17-226: 10.0 metres grading 5.16 g/t Au
  
• SRC17-687: 16.0 metres grading 7.65 g/t Au
  Including: 4.0 metres grading 28.94 g/t Au
  
• SRC17-704: 50.0 metres grading 2.01 g/t Au
  Including: 4.0 metres grading 9.70 g/t Au

(Figure 1, attached to this news release, shows a drill hole plan map)

Craig MacDougall, Senior Vice President, Exploration for IAMGOLD, stated, "we are very pleased with the results of our 2017 program which have not only better delineated high grade structures within the known resource, but have also confirmed extensions of the mineralization to both the north and south along strike beyond the current resource pit shell. These extensions have nearly doubled the strike length of the mineralized foot print and we continue to advance towards our objective of achieving a targeted resource threshold of 2 million ounces."

About the Siribaya Project

The Siribaya project is wholly owned by IAMGOLD and consists of 8 contiguous exploration permits covering 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 totalling 2.1 million tonnes averaging 1.90 grams of gold per tonne for 129,000 ounces and inferred resources comprising 19.8 million tonnes averaging 1.71 grams of gold per tonne for 1.1 million ounces (see news release dated February 22, 2017). 

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 at Siribaya discovered to date, gold mineralization occurs within an albitized sandstone unit similar to that hosting IAMGOLD's Boto gold deposit in Senegal located approximately 10 kilometres to the north along strike.

Next Steps

In 2018, approximately 15,000 metres of drilling is planned to continue defining and expanding resources at the Diakha deposit as well as to explore other identified priority targets. All results will be used to refine the deposit model and will be incorporated into an updated resource estimate expected by year end.

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 the 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 kilogram samples.  One sample is retained for reference purposes and the other is used to prepare two-metre composite samples for assay. The two-meter composite samples are prepared at the project site, by trained technicians supervised by IAMGOLD geologists. 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.

Notes to Investors Regarding the Use of Resources

Cautionary Note to Investors Concerning Estimates of Indicated and Inferred Resources
This news release uses the term "indicated resources". We advise investors that while that term is recognized and required by Canadian regulations, the United States Securities and Exchange Commission (the "SEC") does not recognize it. Investors are cautioned not to assume that any part or all of mineral deposits in this category will ever be converted into reserves. 

This news release also uses the term "inferred resources". We advise investors that while this term is recognized and required by Canadian regulations, the SEC does not recognize it. "Inferred resources" have a great amount of uncertainty as to their existence, and great uncertainty as to their economic and legal feasibility. It cannot be assumed that all or any part of an inferred mineral resource will ever be upgraded to a higher category. Under Canadian rules, estimates of inferred mineral resources may not form the basis of feasibility or pre-feasibility studies, except in rare cases. Investors are cautioned not to assume that part or all of an inferred resource exists, or is economically or legally mineable. 

Cautionary Note to U.S. Investors
The SEC limits disclosure for U.S. reporting purposes to mineral deposits that a company can economically and legally extract or produce.  IAMGOLD uses certain terms in this news release, such as "measured," "indicated," or "inferred," which may not be consistent with the reserve definitions established by the SEC.  U.S. investors are urged to consider closely the disclosure in the IAMGOLD Annual Reports on Forms 40-F. You can review and obtain copies of these filings from the SEC's website at http://www.sec.gov/edgar.shtml or by contacting the Investor Relations department.

The Canadian Securities Administrators' National Instrument 43-101 ("NI 43-101") requires mining companies to disclose reserves and resources using the subcategories of "proven" reserves, "probable" reserves, "measured" resources, "indicated" resources and "inferred" resources. Mineral resources have not demonstrated economic viability and there can be no assurance that they can be converted to mineral reserves. 

A mineral resource is a concentration or occurrence of natural, solid, inorganic material, or natural, solid fossilized organic material, including base and precious metals in or on the Earth's crust in such form and quantity and of such a grade or quality that it has reasonable prospects for economic extraction. The location, quantity, grade, geological characteristics and continuity of a mineral resource are known, estimated or interpreted from specific geological evidence and knowledge. A measured mineral resource is that part of a mineral resource for which quantity, grade or quality, densities, shape and physical characteristics are so well established that they can be estimated with confidence sufficient to allow the appropriate application of technical and economic parameters, to support production planning and evaluation of the economic viability of the deposit. The estimate is based on detailed and reliable exploration, sampling and testing information gathered through appropriate techniques from locations such as outcrops, trenches, pits, workings and drill holes that are spaced closely enough to confirm both geological and grade continuity. An indicated mineral resource is that part of a mineral resource for which quantity, grade or quality, densities, shape and physical characteristics can be estimated with a level of confidence sufficient to allow the appropriate application of technical and economic parameters to support mine planning and evaluation of the economic viability of the deposit. The estimate is based on detailed and reliable exploration and testing information gathered through appropriate techniques from locations such as outcrops, trenches, pits, workings and drill holes that are spaced closely enough for geological and grade continuity to be reasonably assumed. An inferred mineral resource is that part of a mineral resource for which quantity and grade or quality can be estimated on the basis of geological evidence and limited sampling and reasonably assumed, but not verified, geological and grade continuity. The estimate is based on limited information and sampling gathered through appropriate techniques from locations such as outcrops, trenches, pits, workings and drill holes. Mineral resources which are not mineral reserves do not have demonstrated economic viability. Investors are cautioned not to assume that part or all of an inferred resource exists, or is economically or legally mineable.

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

Laura Young, Director, Investor Relations, IAMGOLD Corporation
Tel: (416) 933-4952 Mobile: (416) 670-3815

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 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 Prospect - 2017 Diamond Drilling results (43 DDH)

Table 2: Drilling Results - Diakha Prospect - 2017 RC program (62 RCH)