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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.
Discovered in 1864 by the engineer Jules Garnier, nickel oxide occurs as an ore named garnierite, resulting from the weathering of peridotites in the ultrabasic massifs which cover about a third of the land surface of the main island of New Caledonia. Nickel has concentrations of 0.2 to 0.3 per cent in the original peridotite. It is liberated by hydrolysis of nickel-bearing silicates, and becomes concentrated towards the base of the weathering profile, where it can attain exploitable concentrations of 2 to 5 per cent (fig. 4). At the weathering front, adjacent to the bedrock and in rock fissures, the nickel content locally attains 10 to 15 per cent in the form of green garnierite, but this very rich ore is present only in small quantities. This was the ore originally mined under artisanal conditions. Modern mechanized methods can utilize less rich ores. At present, the mean concentration of mined nickel ore is about 2.6 per cent, and reserves with at least this concentration are estimated at 200 million tonnes. However, the superficial laterites also contain nickel ore of lower concentration (1.3 to 1.6 per cent), as yet unexploited, but representing enormous reserves for the future. It has been calculated that New Caledonia contains 40 per cent of the known nickel ore resources in the world.
FIG.4. Weathering Profile Characteristic of Hilltop Plateaux on Ultrabasic Massifs in New Caledonia. Shown are the typical locations of nickel ore (garnierite) at the weathering front, and zones of nickel, chromite, and cobalt accumulation beneath the red and yellow laterite horizons and the ferruginous crust. (After Paris 1981.)
Mining of nickel began in 1875 in the Houaílou and Canala regions. By the end of 1981, just over a century of mining had yielded 11 0 million tonnes of nickel ore, equivalent to 2.5 million tonnes of pure nickel. About half of the nickel ore production has been smelted in New Caledonia, the other half being exported, mainly to Japan.
In the early stages, nickel ore was mined by hand in tunnels or trenches which followed the richest seams. Mining has subsequently become opencast, with increasing mechanization. At present, the nickel ore is quarried by powerful mechanical shovels which cut into cliffs five to eight metres high (plates 4 and 5). After sorting, the ore is taken down to coastal wharfs in large lorries, or on conveyor belts which have been built from the more important mining centres. This kind of mining necessitates the removal of huge masses of overburden: it is estimated that an average of five tonnes of rocky material must be removed to obtain one tonne of nickel ore. As a result, vast amounts of earthy waste material have been displaced in the course of nickel mining.
Figure 5 shows the evolution of nickel ore production from 1890 to 1981, and also the accompanying diminution in the nickel content of extracted ore (given as percentage of metal in dried ore, the natural ore containing an average of 25 per cent moisture). Before 1890, nickel ore production was very slight and was poorly recorded, but thereafter, as the graph shows, it increased until the First World War, fell back between 1917 and 1925, then revived in the next 15 years to attain nearly 500,000 tonnes in 1940. After a long period of depression in the 1940s, it began to grow strongly, reaching a million tonnes in 1955. Except for setbacks in 1958 and 1962, expansion continued, attaining a record yield of nearly 8 million tonnes in 1971. Figure 6 shows areas where mining has occurred.
Since 1971 there has been a decline, related to the world economic recession which reduced prices and lowered demand for nickel, and to competition from other nickel-ore-producing countries, notably Indonesia and the Philippines. In spite of a small recovery in 1974-1975, nickel ore production has continued to decline. In 1981 it was less than 4 million tonnes.
Under the legal system operating in the Territory of New Caledonia, mining titles (concessions and exploitation permits) issued for the mining of nickel and associated mineral ores cover 380,000 hectares, about 22 per cent of the surface of the main island of New Caledonia. The bulk of the mining area is shared between eight leading companies, of which the Société Le Nickel (SLN) is the largest, with 175,000 hectares of concessions. The exploited areas have varied considerably. From 21,500 hectares in 1971, the year of maximum production, they have fallen to 8,700 in 1981.
FIG. 5. Development of Nickel Production in New Caledonia 1890 to 1981 and Mean Nickel Content of Mined Ore during That Period
FIG. 6. Main Areas Where Mining Has Taken Place in New Caledonia
Figure 7 shows the distribution of about 330 opencast nickel mines, based on information from the 1:200,000 geological map (Paris 1981). The most important mines (i.e., those that have yielded more than 15,000 tonnes) are represented by large dots on this map. They can be grouped within about 40 centres of exploitation, generally corresponding with the distribution of ultrabasic massifs, and it is in terms of these that production figures are available for 1971 and 1981 (figs. 8 and 9).
Four major mining centres have produced 62 per cent of the nickel ore so far extracted. These are Thio, Kouaoua, and Poro on the east coast and Népoui-Kopeto on the west coast. Mined continuously since the end of the nineteenth century, the deposits of the Plateau de Thio have yielded 17 per cent of the total nickel ore production from New Caledonia, and with the adjacent ThioMission, Ningua, and Ouenghi mines, this region has produced 24 per cent of the nickel ore so far won from New Caledonia. Further north the longexploited mining area of Kouaoua lies in second position with 14 per cent, and the more recently developed centres of Poro and Népoui, developed largely during the "nickel booms of 1968-1973, have yielded 12 per cent each.
FIG. 7. Locations of Nickel, Chromium, Iron, and Manganese Mining in New Caledonia up to 1981
The rest of the nickel ore production has come from a large number of smaller mines, most of which have been worked only sporadically. The most notable, yielding between 2 and 5 per cent of the New Caledonian nickel ore production, have been Ouazangou-Taom, Tontouta, Kaala, Me Maoya, and Koniambo on the west coast, and Nakéty, Canala, Monéo, and Ouinné on the east coast. The Massif de Koniambo was mined until about 1950, and in some years was more productive than the Thio mines. However, in 1950 the Massif de Koniambo mining halted, and this region was placed in reserve. It still contains the largest reserves of rich nickel ore (garnierite) in New Caledonia. Small mining centres in the south. such as Paita, Dumbéa, St. Louis, and Mont Dore have been exploited intermittently, but have nevertheless yielded some 3.5 per cent of total nickel ore production.
Figures 8 and 9 show the distribution of nickel ore producing centres in 1971 (total production 7,720,000 tonnes) and in 1981 (3,980,000 tonnes). In the course of this decade of diminishing mining activity, many small mines worked chiefly to produce nickel ore for export to Japan were closed down, and production became concentrated at the four major mining centres, mainly supplying the SLN factory in Nouméa; with ore for processing. The contribution from these four mining centres increased from 53 per cent of the New Caledonian nickel ore pro duction in 1971 to 72 per cent in 1981, although their actual yield fell from more than 4 million tonnes to less than 3 million tonnes over this period. Kouaoua has now become the principal mining centre, ahead of Thio, Poro, and Népoui. In all, 132 mines were active in 1971, but only 31 in 1981.
FIG. 8. Nickel Ore Production in New Caledonia in 1971 (total production 7,720,000 tonnes)
FIG. 9. Nickel Ore Production in New Caledonia in 1981 (total production 3,980,000 tonnes)
During 1982 the economic situation worsened. The important Ouinné mine ceased activity at the end of the year, and the reduction in demand for nickel led SLN to announce that the Népoui and Poro mining centres would close down in 1983.
Yet, as will be shown in later chapters, the problem of landscape impact of the vast quantities of waste material that has resulted from all this mining activity will not be reduced simply because of the downturn in the economy and the closure of so many nickel mines. This impact is as conspicuous now in the many areas where mining came to an end during the past decade as in the few areas where nickel ore is still being extracted.
Like nickel ore, the chromium ores are associated with the ultrabasic rocks, but their extraction has had much less impact on the landscape because the richest ores are localized and mining has been generally by way of shafts and edits, with only a few opencast workings. The chromium ores occur in two forms: primary chromite in highly concentrated deposits containing at least 50 per cent chromium within the peridotites, and detrital chromite with a much lower chromium content (about 5 per cent) in the laterite capping and in derived fluvial or littoral deposits (chromium content up to 20 per cent).
Chromium ores were mined continuously from 1880 to 1962; production totalled 3,285,000 tonnes, with an average chromium metal content of 53 per cent (fig.10). During this period chromium ore mining produced more metal than nickel ore mining. The bulk of the chromium ore came from the chromite deposits of Tiébaghi, in northern New Caledonia, which yielded 85 per cent of the total production. Extraction was by opencast mining on the Tiébaghi Plateau until 1930, then by underground mining until 1962, when the mines closed. Consequently, waste heaps from the mining of chromium ore are localized and of limited volume. The remaining 15 per cent of chromium ore production came from many small mines, chiefly in the Massif du Sud, where about 80 mines operated, although only a dozen yielded significant chromite production.
Since 1976 there has been a revival of interest in chromium mining in New Caledonia. Three small companies have reopened mines in the Massif du Sud, and a major project is in operation to extract chromite from the Tiébaghi massif by means of underground mining, with an expected production of 100,000 tonnes per year.
The ferruginous laterites and crusts which cap weathered peridotites in the Massif du Sud contain important reserves of iron ore, but their high nickel, chromium, and aluminium content has impeded their exploitation. Nevertheless, these iron ores were mined by opencast methods near Goro between 1937 and 1941 (yielding 400,000 tonnes), and near the Baie de Prony between 1956 and 1968 (yielding 3 million tonnes). Readily accessible in the surface formations, where the iron content attains 55 to 58 per cent, this ore was exported to Japan and Australia. The impact on the landscape has been severe, for removal of ferruginous material has left extensive bare surfaces subject to sheet and gully erosion.
Manganese ores are found associated with basaltic outcrops on the west coast of New Caledonia. Deposits located near Bourail, Poya, and Ouaco were quarried between 1918 and 1922 and again between 1949 and 1953, producing a total of about 60,000 tonnes of ore with an average content of 49 per cent manganese. The ores were exported, mainly to the United States. The landscape impacts of this mining have been negligible in comparison with those resulting from the extraction of nickel and iron ores.
The mining economy of New Caledonia
Nickel metallurgy has accompanied mining since its inception, the remoteness of European markets justifying the smelting of the ore within New Caledonia (Glasser 1904, Antheaume 1981). The first nickel smelter began operating at Pointe Chaleix, Nouméa; in 1879, and two other processing plants were subsequently established, one by the Société des Hauts-Fourneaux de Nouméa; at Doniambo, Nouméa; in 1910, the other by SLN at Thio in 1913. The latter closed in 1931, when the nickel smelting plant at Doniambo passed into the control of SLN.
New Caledonian nickel is produced in two forms, as ferro-nickel alloys (22 to 37 per cent nickel content) which can be used directly in the production of special steels, and more concentrated ingots (75 to 78 per cent nickel), which are sent to Le Havre in France for refinement into purer metal.
Production capacity from Doniambo was doubled between 1970 and 1978 to attain 90,000 tonnes per year of nickel, about 10 per cent of the total nickelproducing capacity of Western countries. However, after growing rapidly to 71,000 tonnes in 1975, nickel production has been severely curtailed by the economic recession. In 1982 SLN produced only 35,000 tonnes of nickel, and production in 1983 is likely to be limited to 24,000 tonnes, just over a quarter of the capacity of the plant.
As a result of the closure of many nickel mines and reduced production, the number of people employed in nickel mining has declined during the past decade (see table 3). By the end of 1982 the number employed had fallen to 1,160. Employment in chromium mining now stands at 128.
The number employed in processing nickel ore at the Doniambo plant fell from 3,394 in 1971 to 2,274 in 1981. In all, employment in mining and metallurgy in New Caledonia has fallen by 42 per cent in this decade, the population of the Territory having grown about 30 per cent over the same period; in 1971 it accounted for 20 per cent of wage earners in New Caledonia, but in 1981 the proportion had fallen to 12 per cent. Société Le Nickel planned to reduce its work-force further during 1983.
Nickel ore and derived metallurgical products represent about 97 per cent of the total value of exports from New Caledonia (i.e., physical exports, excluding income from tourism). Such local products as coffee, copra, and troca furnish only 0.5 per cent of the value of the Territory's exports, the balance consisting mainly of imported items reexported to other Pacific islands, notably Vanuatu, Wallis Island, and French Polynesia.
In 1979 New Caledonian nickel represented about 19 per cent of the total value of exports from the South Pacific region, less than the copper production from Papua New Guinea, which accounted for 23 per cent (Navunisaravi and Rakanace 1980).
TABLE 3. Number of People Employed in Nickel Mining in 1971 and 1981 and Percentage Change
|Société Le Nickel mines||1971||1981||Change(%)|
Figure 11 shows the evolution of the value of exports of nickel ore and metallurgical products from 1 971 to 1 982. They attained 30 billion CFP francs in 1 981 (about US$300 million), but in 1 982 they had declined to 25 billion CFP francs (then equivalent to US$21 0 million). The proportion of nickel ore exported (entirely to Japan) fell from 35 per cent in 1 971 to 1 5 to 20 per cent in the early 1980s.
Imports to New Caledonia have grown considerably in recent years, and the declining value of nickel exports makes it difficult to offset the costs of imports. In the absence of substantial development in other sectors of the economy; New Caledonia is unable to maintain its standard of living without aid from France. By 1 980 mining and metallurgy generated only 1 6 per cent of the gross domestic product of the Territory (compared with 25 to 30 per cent in the early 1970s), while the contribution of the administration (i.e., the wages paid by it) was 23 per cent (fig. 12). Exports in the same year provided only 57 per cent of the total income of the Territory, the balance being supplied from France (Service de la Statistique 1980).
FIG.11. Evolution of the Export Value of Mineral (nickel ore) and Metallurgical Products from New Caledonia, 1971 - 1982 ( FO B value, actual prices)
FIG. 12. Contributions of Mines and Metallurgy and of the Administration to the Economy of New Caledonia between 1960 and 1980 (expressed as percentage of gross domestic product)
It will be evident from this review that mining, especially of nickel ores, has been vital to the development of the New Caledonian economy in its present form, and it is natural that the revival and further expansion of mining activity is seen as the best hope for the revival of the Territory's economy in the future. It is against this economic background, with its social and political undertones, that we turn to consider in more detail the landscape impacts and ecological consequences of the opencast mining that has occurred in the past century in New Caledonia.
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