|The Impacts of Opencast Mining on the Rivers and Coasts of New Caledonia (UNU, 1984, 53 pages)|
|2. The history and economics of mining in New Caledonia|
The mining economy of New Caledonia
The mineral resources of New Caledonia have been the basis of the Territory's economy. In the past few decades, mining has generated more than 90 per cent of exports from New Caledonia its value far exceeding the production from agriculture, forestry, fisheries, and tourism. For more than a century, since the beginnings of colonization, there has been mining of metallic mineral ores, notably of nickel, cobalt, chromium, iron, copper, lead, zinc, gold, silver, manganese, and antimony. In addition, deposits of coal, gypsum, giobertite (magnesium carbonate), and phosphate have been mined.
Much of this mineral exploitation has been very localized, and many of the mines have now been long abandoned; they have left almost no impact on the landscape of New Caledonia. This was particularly the case with the copper, lead, and zinc mines in the north (in the region of Ouégoa), which were worked by shafts and edits (hillside tunnels) rather than opencast pits, and only intermittently. They closed before 1930. Cobalt was also mined in this way. It was found to be associated with nickel ores in the form of asbolane concretions with a mean cobalt content of about 5 per cent. Mining operations were artisanal, many small exploratory excavations seeking and following these concretions through edits cut into the laterites. Between 1890 and 1910 New Caledonia was the world's leading producer of cobalt, but in 1927 production ceased. By then about 100,000 tonnes of cobalt ore had been exported.
The existence of coal deposits in rocks of Senonien age was known from the early years of colonization, but the only significant mining of these deposits took place near Moindou on the west coast between 1924 and 1930. Underground coal mining had very little impact on the landscape, but some 77,000 tonnes of coal were produced during this period and used in nickel smelting. However, by 1930 it had become clear that, because of the poor quality of this coal and the high cost of its extraction, it could not compete with imported Australian coke, and coal mining in New Caledonia was abandoned. Gypsum and giobertite were also used in nickel metallurgy, the first as a sulphurant, the second as a smelter. Small lenticular deposits of gypsum found in old marine or lagoon shore deposits along the west coast were mined between 1917 and 1954, yielding 320,000 tonnes. Giobertite is derived from the weathering of peridotites, and was mined sporadically from several small concentrations at the foot of the massifs along the west coast. This mining ceased in 1970.
Apart from these mineral resources, there are four metallic ores the opencast mining of which has had an impact on the landscape of New Caledonia. Nickel is the most important of these and is still basic to the Territory's economy, but there has also been mining of chromium, iron, and to a lesser extent manganese.