Montagne d’Or Gold Project, French Guiana


Montage d'Or Gold

The Montagne d'Or gold mine is located in north-west French Guiana, approximately 180km west of its capital city, Cayenne.

The preliminary environmental and social impact assessment (ESIA) for the mine was completed in the first quarter of 2015. First gold from the mine is expected to be poured in the fourth quarter of 2021.

The project is anticipated to produce 237,000oz of gold a year in the first ten years at an average grade of 1.73g/t. The overall mine life is expected to be 12 years.

Columbus Gold holds a 45% interest in the Montagne d'Or mine, while Nord Gold (Nordgold) holds the remaining 55% stake.

The project is expected to create 658 permanent direct jobs and up to 3,000 indirect jobs.

Montagne d'Or geology and mineralisation

The Montagne d'Or mine is a part of the Paul Isnard project, which comprises eight mining concessions spanning 190km².

The gold deposit is located within the northern greenstone belt of the Guiana Shield and hosts closely spaced, south-dipping gold-sulphide mineralised horizons.

Gold mineralisation at the mine is associated with primary sulphide minerals as replacements within pyrite and chalcopyrite and is contained within the Paramaca Formation, which is predominantly composed of meta-volcanic and meta-sedimentary units.

The units are believed to be deformed by ductile deformation resulting in tight to isoclinal folding and shearing, as well as a pervasive foliation.

Montagne d'Or gold mine reserves

The Montagne d'Or gold mine is estimated to contain proven and probable mineral reserves of 54.11Mt grading 1.58g/t of Au and containing of 2.75Moz of gold.

Mining at Montagne d'Or

Conventional open-pit mining methods involving drilling and blasting will be applied at the Montagne d'Or mine. Front-end loaders (FELs) and hydraulic excavators will be used for excavating, loading and hauling the ore.

"The project is anticipated to produce 237,000oz of gold a year in the first ten years at an average grade of 1.73g/t."

The mine is planned to be developed in eight phases. The initial two years of the mine plan includes limited pre-stripping, followed by ten years of open-pit mining and two years of low-grade ore stockpile.

Ore processing

The processing plant is designed to have a throughput of 4.5Mt a year with a mill utilisation rate of 91.3%.

The run-of-mine (RoM) ore will be initially crushed in a primary jaw crusher, stockpiled and passed through a single stage semi-autogenous grinding (SAG) mill comprising a pebble crusher and hydrocyclones.

The fine-screened slurry from the cyclone underflow will be sent to a gravity circuit in order to recover gold and silver to the gravity concentrate. Coarse material will be redirected to the SAG mill feed hopper for further processing.

The gravity concentrate will be transported to the gold room for further processing, while the tails slurry will be sent to mill discharge hopper for further processing.

Trash screen underflow from the grinding circuit will be thickened and mixed with a flocculant before forwarding to the pre-leach thickener.

Underflow from the pre-leach thickener will be pumped to the carbon-in-leach (CIL) circuit, which comprises a leach tank and six CIL tanks with carbon for gold adsorption.

The loaded carbon will then be transferred to the elution circuit, which will further undergo electro-winning and smelting to produce gold doré.

Infrastructure at Montagne d'Or

Access to the mine is through a 120km seasonal forest road from Saint Laurent du Maroni, near the port of St. Laurent.

The existing 54km road between the project site and Apatou Crossing, as well as the site roads, earthworks pads and sediment control structures will be renewed. A new 90kV overhead power line to connect the project with the national power grid at Saint Laurent du Maroni will also be constructed.

Workers will be accommodated at the proposed 482-room permanent camp, in addition to the existing camp at Citron.

Contractors involved

Supported by SRK Consulting, Lycopodium Minerals was awarded the contract to prepare the feasibility study for the Montagne d'Or gold deposit in October 2015.

SRK Consulting prepared the NI 43-101 technical report for the gold mine, while WSP Canada was engaged in June 2014 to prepare the ESIA report.

Tractebel Engineering was engaged to conduct a study on connecting the project to the national grid.