THE INDUSTRIAL COMPLEX

 

Vale Inco Nouvelle-Calédonie's production complex for nickel and cobalt has been under construction since 2005 and production is planned to begin progressively from 2008 onwards. The complex covers a surface area of 22 hectares. The plant is made up of modules which have been built abroad, mainly in the Philippines. Once preassembled, these modules are delivered to the site for assembly as and when the foundations and infrastructures are ready for them.

In addition to related installations (power station and port), the industrial complex has two main components-the hydrometallurgical plant for processing ore and the waste treatment plant

The hydrometallurgical plant

The Vale Inco Nouvelle-Calédonie factory will use the fourth generation hydrometallurgical process for nickel which Inco has developed.

Pressure Acid Leaching (PAL) uses less energy, is more respectful towards the environment and is more cost-effective than traditional extraction methods, in particular pyrometallurgical methods.

The pilot plant has recorded excellent extraction rates for nickel and cobalt and this has led to the decision to construct a commercial plant

At full capacity, the factory will produce 60,000 tonnes of nickel and between 4600 and 5500 tonnes of cobalt per year. A workforce of approximately 800 employees will be required.

The waste treatment plant

The process of extracting ore to produce nickel oxide and cobalt carbonate will generate both solid waste and liquid waste. This will be taken to the waste treatment plant to be neutralised before disposal.

Up to 60% of water in the circuit is recycled and some materials used in the process are also reintroduced into the circuit. Solid and liquid waste which cannot be recycled is neutralised with lime and limestone.

Neutralised solid waste will be used to fill mine pits as mining progresses in order to rehabilitate the landscape and be able to proceed to replanting.

The processed liquid effluent is compatible with the marine environment. It has a pH level comparable to that of seawater and a similar composition of dissolved elements (mainly, sodium, chloride, magnesium sulphate, calcium and manganese). This is why this effluent can be disposed of naturally in the sea without posing any danger to the environment.