A pre-feasibility study on IAMGOLD Corp.'s proposed heap leach operation at its open pit Essakane gold mine in Burkina Faso estimated initial CapEx at US$155 million.
The company said June 5 that the pre-feasibility study indicated an economically viable project, and feasibility work is underway to further optimize development design, secure long-lead equipment and improve project economics. The feasibility study is expected to be completed in the first quarter of 2019.
The Essakane heap leach project is expected to produce an average 471,000 ounces of gold per year over an 8.5-year mine life, with cash costs averaging US$707/oz and all-in sustaining costs averaging US$946/oz over the life of the mine.
The study defined a maximum annual mining rate of 70 million tonnes per year, with a carbon-in-leach milling capacity of 12 Mt/y and a heap leach processing capacity of 10 Mt/y. The study was based on a gold price of US$1,275/oz.
IAMGOLD said the estimated mine life increased by three years as compared to a 2016 technical report, with potential for a further increase with the feasibility study and drilling of satellite deposits.
The company also said recent infill drilling intersected higher-than-expected grades in several areas, which could provide additional higher-grade mineralization for processing at the existing carbon-in-leach plant.
The Essakane heap leach analysis included updated estimates of reserves and resources, with gold contained in reserves increasing 39% to 4.7 million ounces. The property hosts probable reserves and stockpiles totaling 164.5 million tonnes grading 0.89 g/t of gold.
Reserves are included within indicated resources of 167.1 million tonnes grading 0.95 g/t of gold for 5.1 million ounces, while inferred resources are estimated at 21 million tonnes grading 0.88 g/t of gold for 595,000 ounces.
Indicated resources increased 19% and inferred resources increased 54% in terms of contained gold. The estimate uses various cutoff grades depending on the deposit and the type of material and does not incorporate mining depletion in 2018.
"Stay tuned for an initial resource estimate for the Gossey prospect in the fourth quarter of this year," IAMGOLD President and CEO Steve Letwin said. "With these positive results and the future work we have planned, we are targeting a mine life beyond 2030 and all-in sustaining costs below US$900 an ounce."
