Grand Terre, New Caledonia
The Goro Nickel Project located on the South Pacific island of New Caledonia commenced production in August 2010 with an annual design capacity of 60,000t of nickel and up to 5,000t of cobalt.
Goro is considered among the world’s best-known laterite ore bodies, with 55 million tonnes (Mt) of estimated measured and indicated mineral reserves. Goro was acquired by Brazilian iron ore and nickel giant CVRD in 2007 after its friendly $19bn takeover bid for Inco.
The Goro project is owned by Vale Nouvelle-Calédonie (Operator, 95%) and Société de Participation Minière du Sud Calédonien (5%).
The total cost of development was estimated at $3.2bn. Exploration of the site was first carried out in 1969. Production at the Goro nickel plant began in 2011 and was halted in May 2014 following spillage of approximately 100,000 litres of effluent in a creek due to the solution transferring circuit misconfiguration.
Nickel production at the Goro mine reached its peak 37,400t in 2017 and totalled 23,700t in 2019. The mine is expected to produce 31,000t in 2020.
The deposit on the Goro Plateau in New Caledonia is a classic deposit in its composition. It comprises iron oxides on the surface (laterites) and magnesium silicates beneath (saprolite).
The nickel and cobalt contained therein result from chemical concentrations within this residual formation.
Of the world’s laterite deposits, this has one of the highest nickel contents. It is estimated to hold 95.5Mt of proven and probable reserves, grading 1.4% nickel and 0.12% cobalt.
The measured and indicated resources are estimated at 98Mt, grading 1.32% nickel and 0.15% cobalt.
The mine on the Goro plateau is opencast, dug to a depth of 50 to 60m. It was estimated that some four million tonnes of dry ore would be removed each year, with 12Mt of earth shifted.
Initially, the superficial layers which have no commercial use are cleared away from the plateau area. The laterite and saprolite ore is extracted from a series of terraces using hydraulic excavators and bulldozers. Haulage is being undertaken by a fleet of dumper trucks.
The deposit is a single, continuous but thick layer, therefore several faces will be opened laterally and vertically so that the entire profile can be extracted from the surface lateritic layer and the saprolite which is further down.
The mine has been given a life of 29 years, during which time mining pits will be filled and replanted at the end of each mining cycle until 2041.
AECOM provided port planning and engineering support services for the project.
Vale boasts that its mining processes involve state-of-the-art, fourth-generation hydrometallurgical techniques, designed to make it possible to profitably process laterites with low nickel content at low cost while reducing the impact on the environment.
The mined ore is screened and ground and then mixed with water to create a combined pulp of limonite and saprolite. Rigorous control of chemical quality and particle size is undertaken.
The pulp is then conveyed via a pipe which extends for 8km to the autoclave at the processing plant.
Vale is planning a second phase for Goro for the next decade, so there is a huge financial commitment riding on project completion and in reaching an accord with project opponents.
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