AIR QUALITY

Atmospheric emissions generated by the plant during operation will be 3 to 5 times lower than emissions from the more traditional pyrometallurgical process. The main reason for such a lower level of emissions is the process itself, which consumes less energy, and the use of fuels with a low sulphur content.

Composition and sources of emissions

Whitish smoke containing standard combustion gases: CO2, SO2, NOx, water vapour and dust.

• Prony Energies power plant : coal-fired power plant with a 100 MW capacity, which will supply power equally to the Vale Inco Nouvelle-Calédonie project and the national electricity network. Coal was chosen for three reasons:
  • Low stable prices – compared with fuel
  • Reduced SO2 emissions (sulphur content is less than 0.45%)
  • Ease of procurement (from Australia)
    
    
• Vale Inco Nouvelle-Calédonie acid leaching plant which consumes three times less energy than a traditional metallurgical plant, emissions being reduced in the same proportions. The sulphuric acid production plant will be the main source of emissions.

Standards and checks

Vale Inco Nouvelle-Calédonie is committed to compliance with European and international public health and wildlife protection standards and with even more rigorous Australian standards for the protection of tropical ecosystems. 

Powerful filtration and purification systems will be put in place:

• All smokestacks will be monitored to ensure emission standards are met
• An air quality surveillance network comprising 5 air quality checkpoints covering the entire region
• A specific prevention and surveillance plan has been implemented to safeguard the unique flora found in the North Forest.

The asbestos issue

Asbestos is a natural mineral fibrous substance. Extensive inhalation of some types of asbestos can cause pulmonary disease. Asbestos is found in greater or lesser quantities throughout New Caledonia.

The Goro mine is at the bottom of a humid valley mainly composed of laterite material. It does not contain any of the dry rocks that are more likely to contain and especially to release asbestos into the air if disturbed. The only parts of the Goro mine likely to contain asbestos are the saprolite and parent rock found at the bottom of the mine. Since the mine is gorged with water there is little risk of dust being released.

Checks were carried out for work at the Antenne pass where a road has been constructed. The various geological studies undertaken on the pass revealed the presence of serpentine, a mineralogical group that can contain chrysotile asbestos (or white asbestos) fibres.  

Large numbers of borehole, surface and air samples were taken. One single sample revealed a minute concentration of chrysotile in the air corresponding to 0.0037 fibre/ cm3.

In accordance with the precautionary principle, field sampling of air is still done on a daily basis, using fixed checkpoints and mobile pumps carried by workers, to ensure that no health hazard exists.