IAMGOLD Corporation (TSX:IMG) today announced positive results from a Feasibility Study for its Boto Gold Project in Senegal, West Africa. The results outline an economically robust project with an anticipated low cost of production and long operating life. The FS demonstrates a significant economic and operational improvement compared to the Pre-feasibility Study results announced in February of this year. The FS will be used to support an application for a mining concession in the fourth quarter of 2018.

PROJECT HIGHLIGHTS (100% BASIS)

• Proven and Probable Reserves (“P&P”) increased by 0.51 million ounces to 1.93 million ounces grading 1.71 g/t Au versus the P&P Reserves from the PFS
• Indicated Resources (including Reserves) of 2.49 million ounces grading 1.61 g/t Au
• Mine Life of 12.8 years with mill throughput of 2.75 million tonnes per annum
• Life of Mine (“LOM”) average annual production of 140,000 ounces, averaging 160,000 ounces annually during the first six years
• LOM cash costs of $714/oz and all-in sustaining costs of $753/oz
• After-tax Internal Rate of Return of 23%, with a payback period of 3.4 years
• Net Present Value of $261 million (6% discount rate) at a gold price of $1,250/oz
• Initial capital expenditures of $254 million

Steve Letwin, President and CEO of IAMGOLD, said “Boto Gold has evolved from a grass roots exploration discovery to a robust development project with nearly 2 million ounces in reserves. I congratulate the team for their success in improving the project economics by as much as they have. The 23% after-tax IRR and the 151% increase in the NPV at a lower gold price assumption are marked improvements from those reported in the pre-feasibility study. This is a solid, low-cost project which is expected to deliver 140,000 ounces annually, on average, for nearly 13 years. While a final investment decision is yet to be made, and there is still permitting work to be done, we’re looking at a high-value project that adds to IAMGOLD’s already impressive growth profile.”

The FS was completed jointly by IAMGOLD and Lycopodium Minerals Canada Ltd, with inputs from technical studies completed by Specialist Consultants. The FS represents a comprehensive study of the technical and economic viability of a mineral project that has advanced to a stage where a preferred mining method is established and an effective method of mineral processing is determined.

A technical report summarizing the FS will be filed on SEDAR tomorrow.

FS HIGHLIGHTS (100% BASIS)

€/US$ exchange rate of 1:1.20; Oil price of $75 per barrel

MINERAL RESOURCES

The Mineral Resource estimate used as the basis for the study is summarized below.

MINERAL RESERVES

The tonnes, grades, and classification of the Mineral Reserves captured within the FS mine plan are summarized below.

MINING AND PROCESSING

The FS confirms the preferred development approach to be a conventional truck and shovel open pit mining operation with a mineral processing circuit incorporating primary crushing, grinding, and cyanide leaching, followed by gold recovery using carbon-in-pulp, stripping and electrowinning.

Open pit mining includes approximately 14 Mt of waste stripping and 2 Mt of ore stockpiling in pre-production mining during a fifteen month pre-production period followed by 12.8 years of production mining along with stockpile reclaim.  Maximum mining rate is 33 Mt per annum.  The average ore grade is 1.71 g/t Au and the LOM stripping ratio is 5.8:1.

Future Work

The FS will be used to support an application for a mining concession to be submitted in the fourth quarter of 2018, with approval expected in the first half of 2019.  In the interim, the project team will continue to optimize aspects of the project design and complete an infrastructure condemnation drilling program. The exploration team has worked to consolidate additional exploration concessions near the Boto Gold Project, and will conduct ongoing exploration to expand resources in proximity to the resource pits, and identify and evaluate high priority exploration targets for additional mineral resources.

Qualified Persons

The FS was prepared by IAMGOLD and Lycopodium and incorporates the work of IAMGOLD, Lycopodium and Specialist Consultants Qualified Persons (QPs) (as defined under National Instrument 43-101). QPs are independent of IAMGOLD and have reviewed and approved this news release.  IAMGOLD QPs are not independent of IAMGOLD and have reviewed and approved this news release. The areas of responsibility for each QP involved in preparing the FS, upon which the technical report will be based, are:

Lycopodium QPs

• N. Lincoln, P. Eng., Summary, introduction, project infrastructure, reliance on other experts, metallurgical testing and mineral processing, recovery methods, overall capital and plant operating costs
• R. McIsaac P. Eng. (Knights Piésold), Tailings and water management

Specialist Consultants QPs

• P. Daigle, P.Eng. (AGP Mining Consultants) Summary, accessibility, geological setting, deposit type, exploration, drilling, sample preparation and analysis and security, data verification, mineral resource estimate
• G. Zurowski, P. Eng. (AGP Mining Consultants), Summary, mine design, mine capital and operating costs, reserve estimate
• R. Thomas, MAusIMM CP Geotech (Absolute Geotechnics Consultant), Open pit geotechnical

IAMGOLD QPs

• M. Lanctot, Ing., Summary, property description, historical setting, permitting, financial analysis and adjacent properties

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.

About IAMGOLD

IAMGOLD 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.