The Montagne d'Or gold project, in French Guiana, has a new project design, which reduces the surface footprint by 32% and the estimated total equivalent carbon dioxide emissions (TECO₂) by 80%, part-owner Orea Mining reported on Wednesday.

Orea president and CEO Rock Lefrançois said the optimised design was the culmination of two years of additional technical and environmental studies in response to the public debate held in 2018.

"This is undoubtedly a pivotal step for the acceptability and development of an exceptional gold deposit."

The joint venture completed a comprehensive analysis of the initial bankable feasibility study (BFS) project design, taking numerous alternatives into consideration before selecting the option that best addressed the concerns brought forth by the public debate.

The alternative designs were scored on environmental, technical and economic criteria with weighting factors of 60, 20 and 20, respectively. The option with the highest score was chosen for the new project design.

The significant reduction in environmental impact was mainly driven by an alternate power generation solution.

Power will be generated by an on-site hybrid power plant capable of 80% solar-based energy, resulting in a reduction in estimated total equivalent TECO₂ of 469 000 t/y. The hybrid power plant will reduce the surface footprint of the project, and consequently, reduce the TECO₂ by an additional 41 600 t/y.

The tailings storage facility (TSF) was optimised for safety and durability.

Two sections of the 120-km access road were redesigned in order to bypass the town of Saint-Laurent-du-Maroni and improve road safety and facilitate heavy vehicle traffic while complying with environmental requirements. The modifications will also shorten the distance to the mine site.

Quarry sites exclusive to the mining project will be developed to meet the heavy demands for construction material and project timelines and reduce the environmental impact related to the transport of material.

The project's occupancy of the forest land has been significantly reduced. The total land impacted has been reduced by 32% compared with the initial project, notably a 44% reduction of impacted mature forests.

Operator Nord Gold earned a 50.01% interest in the proejct in September 2017 by spending $30-million and completing the BFS.

Montagne d'Or hosts measured mineral resources of 10.3-million tonnes at 1.804 g/t (600 000 oz), indicated mineral resources of 74.8-million tonnes at 1.350 g/t (3.25-million ounces) and additional inferred resources of 20.2-million tonnes at 1.48 g/t gold (960 000 oz).

The 2017 BFS contemplates an openpit operation over a 12-year mine life, producing an average of 237 000 oz/y at an all-in sustaining cost of $749/oz.