All amounts are in US dollars, unless otherwise indicated.
Numbers in tables may not add due to rounding.
TORONTO, June 5, 2018 /CNW/ - IAMGOLD Corporation ("IAMGOLD" or the "Company") today announced positive results from a Pre-feasibility Study ("PFS") for its Essakane Heap Leach Project (the "Project") in Burkina Faso, West Africa. The results, which outline an economically viable project, justify the commencement of a Feasibility Study ("FS") to further optimize the project development design, secure long lead equipment and improve project economics.

PRE-FEASIBILITY HIGHLIGHTS (100% BASIS)
•Probable Reserves increased by 39%, or 1.3 million ounces, to 4.7 million ounces.
•Indicated Resources increased by 19%, or 0.8 million ounces, to 5.1 million ounces.
•Inferred Resources increased by 54%, or 0.2 million ounces, to 0.6 million ounces.
•Mine Life of 8.5 years (2018-2026) with mill throughput of 12.0 million tonnes per annum and heap leach throughput of 10.0 million tonnes per annum (2020-2026).
•Mine life extended by three years from the LOM reported in the 2016 Technical Report, with potential to extend further with the FS and the drilling of prospective satellite prospects near Essakane.
•Average annual production increases by 16% to 480,000 ounces versus previously disclosed plan, once heap leach is operational.
•Peak annual production exceeding 500,000 ounces.
•LOM cash costs of $707/oz and all-in sustaining costs of $946/oz.
•Heap Leach initial capital expenditures of $155 million.


The infill drilling program, conducted to upgrade targeted lower-grade inferred resources in support of the Heap Leach PFS, intersected higher grades than anticipated in several areas. The impact of these results is still being assessed and may provide potential to outline additional zones of higher-grade mineralization for processing at the existing carbon-in-leach ("CIL") plant. The drilling campaign is continuing and the results will be used to complete the delineation of both the lower-grade heap leach and higher-grade CIL mineralization to optimize the development options as part of the recommended FS.

"I applaud the Essakane team," said Steve Letwin, President and CEO of IAMGOLD. "Not only have they introduced a new processing method that allows for economic incremental production, their success at the drill bit has delivered a resource increase far greater than what we expected. While we knew that heap leaching had the potential to unlock additional reserves, we were positively surprised at, and benefited from, intercepting higher grades, which account for more than one-third of the 39% increase. Essakane is pursuing all avenues for enhancing the value of this already high-performing operation, including targeting additional resources from Essakane's large, prospective land package. Stay tuned for an initial resource estimate for the Gossey prospect in the fourth quarter of this year. With these positive results and the future work we have planned, we are targeting a mine life beyond 2030 and AISC below $900 an ounce."

The PFS was completed jointly by IAMGOLD and Kappes, Cassiday & Associates (KCA), with inputs from technical studies completed by other consultants, and has an effective date of June 5, 2018. The PFS 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 has been established and an effective method of mineral processing has been determined. IAMGOLD is using the PFS to identify the preferred development option to demonstrate economic viability of the Project, to support Mineral Reserve disclosure, and to identify additional work recommended to support the completion of a FS. Technical studies to support the completion of the FS have commenced, with the study scheduled for completion in the first quarter of 2019. As a result of the newly established reserve estimate, and the intercepted high-grade material at depth, the FS will also evaluate a lower capital option focused on enhancing the CIL plant only to potentially reduce the LOM AISC while improving the LOM NPV.

A technical report summarizing the PFS will be filed on SEDAR within 45 days of the date of this news release.

PFS HIGHLIGHTS
Project Economics and Key Parameters
Mining Capacity 70.0 Mtpa
Carbon-in-leach (CIL) Milling Capacity 12.0 Mtpa
Heap Leach (HL) Processing Capacity 10.0 Mtpa
LOM Average Annual Gold Production (CIL, 8.5 years) 416,000 oz.
LOM Average Annual Gold Production (HL, 6.5 years) 72,000 oz.
LOM Average Annual Gold Production (8.5 years) 471,000 oz.
LOM Average Recovery Rate (CIL) 92.1%
LOM Average Recovery Rate (HL) 55.0%
Mine Life (2018-2026) 8.5 years
LOM Average Cash Costs (incl. Royalties) $707/oz
LOM Average AISC $946/oz
Average diluted grade CIL 1.17 g/t Au
Average diluted grade HL 0.43 g/t Au
Average LOM Strip Ratio (Remaining Pit) 2.34:1
Estimated Initial Capital Expenditure* (millions) $155
Gold Price Assumption used in financial analysis $1,275/oz

US$/C$ exchange rate of 1:1.25. US$/€ exchange rate of: 1:0.83

*Initial capital expenditures exclude fleet

MINERAL RESOURCES

The Mineral Resource estimate used as the basis for the study is summarized below.
Mineral Resources (100% Basis) – June 5, 2018

Classification
Tonnes (000) Grade (g/t Au) Contained Ounces (000)
Indicated 167,067 0.95 5,101
Inferred 20,994 0.88 595

Notes: 1. CIM Definition Standards were followed for classification of Mineral Resources.
2. Mineral Resources reported at a cut-off grade for Essakane main zone of 0.33 g/t Au for saprolite, 0.43 g/t Au for transition material and 0.30 g/t Au for fresh rock material. Cut-off grades for Falagountou are 0.36 g/t Au for saprolite, 0.46 g/t Au for transition material and 0.52 g/t Au for fresh rock material.
3. Mineral Resources do not include 2018 depletion.
4. Mineral Resources are constrained within a pit shell estimated using a long-term gold price of $1,500/oz and a US$/€ exchange rate of: 1:0.77 and a US$/CFA exchange rate of 1:0.00198.
5. Mineral Resources are inclusive of Reserves quoted below.
6. Mineral Resources are reported on a 100% basis.

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