IAMGOLD has announced positive results from a PFS for its Essakane Heap Leach Project in Burkina Faso, West Africa. The results, which outline an economically viable project, justify the commencement of a Feasibility Study (“FS”) to further optimise the project development design, secure long lead equipment and improve project economics. PFS highlights include:

• 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 mineralisation 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 mineralisation to optimise 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.

The PFS has identified the positive benefit of two extra mining phases to the existing Essakane main zone (EMZ) open pit mining operation combined with the addition of a heap leaching operation. The heap leaching operation would be run in parallel to the existing process plant. Dedicated primary (gyratory) and secondary (cone) crushing circuits, tertiary crushing using a high pressure grinding rolls (HPGR) unit, material handling and stacking conveyors, and a carbon in column (CIC) adsorption plant would be installed. Loaded carbon would be transported to the existing plant facilities for stripping and refining where minimal infrastructure upgrade would be required. Where possible, the specified equipment would be the same model as that used in the CIL plant to improve maintainability and to reduce parts inventories.

Additional major infrastructure included in the PFS are the leach pad, solution distribution and collection systems, solution ponds, camp upgrade and power generation capacity increase. Remaining open pit mining includes approximately 343 Mt of waste and 146 Mt of ore over an 8.5-year-period of production mining. This volume of waste would decrease if in-pit inferred resources can be converted to CIL or Heap Leach ore through infill drilling. Stockpile reclaim would commence in 2020 until depletion at the end of the mine life. Maximum mining rate is 70 Mt per annum. The average mined grade is 0.94 g/t Au and the LOM stripping ratio is 2.34:1. The average processed grade is 0.89 g/t (1.17 CIL and 0.43 HL).

The PFS recommends the completion of a FS to validate and detail the elements of the development concept set out in the PFS, and would include additional infill and condemnation drilling, additional lab column testing, engineering studies and construction planning. Environmental studies, resettlement action planning and permitting initiatives which have all been initiated during the PFS stage will also continue during the FS. Environmental and social baseline evaluation has been completed and a permit application is planned for the third quarter 2018.

The recommended FS work has already been initiated and is expected to be completed in the first quarter of 2019, using a 10 Mt per annum heap leaching processing rate. In addition, the FS will evaluate additional development alternatives, such as a gravity circuit upgrade and an increase in grinding capacity. This strategy aims to increase the throughput and recovery of the CIL and gravity circuits in parallel, in order to bring additional value to the processing plant.