IAMGOLD Announces Final Assay Results from 2016 Drilling Program at Saramacca Project

(A drill hole plan map is attached to this news release.)

"The potential of the Saramacca property and the neighbouring Sarafina property will leverage off of our existing infrastructure and represent an excellent brownfield opportunity with greenfield excitement," said Steve Letwin, President and Chief Executive Officer for IAMGOLD.   "I'm very proud of what the Rosebel team has done to reinvent their mine through cost reductions and performance improvements.   Their hard work has extended the mine life well beyond our previous expectations and has given them the time to acquire access to and explore the potential of properties such as Saramacca.  The encouraging results from the 2016 drill program at Saramacca indicate that this property has the potential to be transformative for the future of Rosebel and very beneficial to all our stakeholders, including our partner the Government of Suriname, just as we envisaged when we bought this property."

Craig MacDougall, Senior Vice President, Exploration for IAMGOLD, stated: "First I want to recognize the efforts of our exploration team to advance the Saramacca project so quickly since its acquisition.  The assay results from the 2016 drilling program are encouraging and appear to confirm the presence of significant mineralization. It is particularly pleasing to note the amount of mineralized intersections in 'soft' saprolite extending to depths of up to 100 metres. With continued success, we expect our 2017 infill drilling program to ultimately lead to the estimation of an initial resource for this project, which would mark a significant milestone for our exploration program at Rosebel."

2016 Exploration Program

The Saramacca project is strategically located approximately 25 kilometers southwest of the Rosebel Gold Mine milling facility. Mineralization is hosted in the Paramaka Formation within the lower part of the Marowijne Greenstone Belt, which is dominated by metamorphosed dacite, rhyolite, basalt and andesite lithologies in the project area.  These are traversed by the regional, northwest trending Saramacca shear zone, an important deformation zone for the localization of gold mineralization.

The 2016 drilling program was designed to duplicate a number of historic mineralized drilling intersections obtained by previous explorers as well as test the full strike and width of the interpreted mineralized footprint on a nominal 100 x 50 metre drill hole spacing.  Duplicate holes successfully confirmed previous exploration results.   As well, many holes intersected mineralization hosted in soft saprolite to depths from surface ranging between 50 to 100 metres.  The program has confirmed the presence of multiple mineralized structures within an approximately 2 kilometres long and 600 metres wide corridor. Mineralization remains open along strike and at depth.  

Three mineralization types are recognized from the drilling to date: breccia hosted mineralization characterized by jigsaw, crackle and matrix supported breccias; shear hosted mineralization characterized by well-developed pyritic disseminations and stringers; and irregular pyrite-quartz-carbonate veins which locally carry high gold grades.

Next Steps

The 2017 exploration program has commenced, with 2 diamond drill rigs currently operating. A phase I drilling program comprised of approximately 15,000 metres of diamond drilling will focus on completing a 50 x 50 metre infill drilling pattern to further define and confirm continuity of the key mineralized structures.  Results will be incorporated into a deposit model to support an initial NI 43-101 compliant resource estimate expected for completion by the third quarter 2017.  

In addition, geological mapping and geophysical surveys will commence along the Saramacca structural corridor to define further targets for drill testing.

About the Saramacca Project

The Saramacca property has been explored since the 1990's principally by Golden Star and later as a joint venture between Golden Star Resources Ltd. ("Golden Star") and Newmont Mining Corporation. Much of that work focused on the discovery and delineation of Anomaly M, which was the subject of successive auger and diamond drilling programs with over 50 diamond drill holes and over 200 auger holes completed in the anomaly area. Evaluation of this work suggests an exploration target potential of between 8 and 40 million tonnes grading between 1.0 and 1.8 g/t Au for potentially 0.5 to 1.4 million contained ounces of gold. The potential quantity and grade are conceptual in nature and insufficient exploration work has been completed to date to define a mineral resource. The property will require significant future exploration to advance to a resource stage and there can be no certainty that the exploration target will result in a mineral resource being defined.

On August 30, 2016, the Company signed a letter of intent with the Government of Suriname to acquire rights to the Saramacca property, with the intent of defining a National Instrument 43-101 compliant mineral resource within 24 months. The terms of the letter included an initial payment of $0.2 million, which enabled immediate access to the property for Rosebel's exploration team to conduct due diligence, as well as access to the data from previous exploration activity at the Saramacca property. On September 30, 2016, having been satisfied with the results of the due diligence, the Company ratified the letter of intent to acquire the Saramacca property and subsequently paid $10 million in cash and agreed to issue 3.125 million IAMGOLD common shares to the Government of Suriname in three approximately equal annual instalments on each successive anniversary of the date the right of exploration was transferred to Rosebel (December 14, 2016). In addition, the agreement provides for a potential upward adjustment to the purchase price based on the contained gold ounces identified by Rosebel in National Instrument 43-101 measured and indicated resource categories , within a certain Whittle shell over the first 24 months, to a maximum of $10 million.

The Saramacca project falls within the "UJV" area as defined in an Agreement with the Government of Suriname announced on April 15, 2013.  The Agreement establishes a joint venture growth vehicle under which Rosebel would hold a 70% participating interest and the Government will acquire a 30% participating interest on a fully-paid basis.

Qualified Persons and Technical Information

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, verification and review of the technical information in this release is Ian Stockton, MAusIMM, MAIG, Exploration Manager for IAMGOLD in Suriname.  He 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 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, drill core is monitored through the implementation of a quality assurance - quality control (QA-QC) program designed to follow industry best practice. Drill core (HQ and NQ size) samples are selected by the IAMGOLD geologists and sawn in half with a diamond saw at the Rosebel mine 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.

Reverse circulation samples (RC) are passed through a rotary splitter and collected in 1 metre intervals and combined to form 2 metre assay intervals, (except wet samples which are sampled without the splitter) for submission of a 4 - 5 kilogram sample to the assay lab.  The 1 metre samples are maintained for future reference and a reference sample is collected and stored in a chip tray. QA-QC is carried out as per above.

Samples are transported in sealed bags to FILAB in Paramaribo, Suriname, a representative lab of ALS.  FILAB is an ISO 9001 (2008) and ISO/IEC 170250 accredited laboratory. Samples are weighed and coarse crushed to <2.5 mm, and 350-450grams is Pulverized to 85% passing<100 μm.  Samples are analyzed for gold using standard fire assay technique with a 50 gram charge and an Atomic Absorption (AA) finish.  Multi-element analysis (40 elements) using ICPAES multi-acid digest is also undertaken.  IAMGOLD inserts blanks and certified reference standard in the sample sequence for quality control.  Samples representative of the various lithologies are collected from each drill hole and measured for bulk density at the site RGM laboratory.