In 1990 the mining industry accounted for less than 1 percent of the total GDP. A wide range of minerals existed in SUDAN , but the size of reserves had not been determined in most cases. The discovery of commercially exploitable quantities of petroleum in the late 1970s offered some hope that the sector would play an increased role in the economy in the future. However, from February 1984, some months after concessions were allotted, oil exploration operations had been suspended in the south, where the largest deposits were located, as a result of the region's security problems. Nonhydrocarbon minerals of actual or potential commercial value included gold, chrome, copper, iron, manganese, asbestos, gypsum, mica, limestone, marble, and uranium. Gold had been mined in the Red Sea Hills since pharaonic times. Between 1900 and 1954, several British enterprises worked gold mines in the area, and extracted a considerable quantity of the metal--one mine alone reportedly produced three tons of gold between 1924 and 1936. Gold also has been mined along the borders between SUDAN and Uganda and Zaire, but not in commercially profitable amounts. During the 1970s, the government's Geological Survey Administration located more than fifty potential gold-producing sites in different parts of the country. Several joint ventures between the SUDAN ese Mining Corporation, a government enterprise, and foreign companies were launched in the 1980s; these undertakings produced gold at Gebeit and several other mines near the Red Sea Hills beginning in 1987. In 1988, about 78,000 metric kilograms of gold ore were mined in SUDAN . In late 1990, SUDAN and two French mining companies formed a joint venture company to exploit gold reserves in the Khawr Ariab wadi in the Red Sea Hills.
Chrome ore was mined in the Ingessana Hills in Al Awsat. In the late 1970s, output was reportedly more than 20,000 tons a year, of which more than four-fifths were produced by the Ingessana Hills Mines Corporation, a subsidiary of SUDAN ese Mining Corporation. A private operation produced the remainder. The ore was exported, chiefly to Japan and Western Europe. In the 1980s, the establishment of ferrochrome processing facilities had been discussed with Japanese interests, but the estimated 700,000 tons of reserves were insufficient for profitable longterm operations. By 1983, when the civil war brought a halt to all production in the Ingessana Hills, chrome production had declined about 50 percent to only 10,000 tons per year. In 1988, production of chromium ore was estimated at 5,000 metric tons. Asbestos had also been found in the Ingessana Hills area. It was reportedly of good commercial grade, and mining possibilities were under study by a Canadian subsidiary of the United States firm of Johns-Manville. A small pilot extraction plant had been built, but larger scale operations were dependent on locating adequate reserves and on the ending of the civil war.
Large gypsum deposits, estimated to contain reserves of 220 million tons, were found along the Red Sea coast. Reportedly of high purity, the ore was mined mainly north of Port SUDAN . In the late 1980s, about 20,000 tons were produced annually, about 6,000 tons by the SUDAN ese Mining Corporation and the remainder by private operations. Gypsum was used mostly in the production of cement. Limestone, found in substantial quantities in SUDAN , was mined both for use in making cement and for other construction materials. Marble was also quarried for the latter purpose.
There has been some commercial mining of mica, exploitable deposits of which had been located in Ash Shamali Province by a UN mineral survey team between 1968 and 1972. The SUDAN ese Mining Corporation produced about 1,000 tons of scrap mica in FY 1978, but output reportedly slumped thereafter to about 400 tons annually. Manganese and iron ore, of which several large deposits exist in different parts of the country, have been mined at times but only on a small basis by international standards. There were more than 500 million tons of iron ore deposits in the Fodikwan area of the Red Sea Hills, and beginning in the late 1980s a project had been planned to produce between 120,000 and 200,000 tons a month. Exploitation of SUDAN 's mineral deposits, however, depended in large part on foreign companies willing to undertake such risks in the face of the country's mounting problems, and on international market factors.
Uranium ores have been discovered in the area of the Nuba Mountains and at Hufrat an Nahas in southern Kurdufan. Minex Company of the United States obtained a 36,000-square-kilometer exploratory concession in the Kurdufan area in 1977, and the concession was increased to 48,000 square kilometers in 1979. Uranium reserves are also believed to exist near the western borders with Chad and Central African Republic. Another potential source of mineral wealth was the Red Sea bed. In 1974 officials established a joint SUDAN ese-Saudi Arabian agency to develop those resources, which included zinc, silver, copper, and other minerals. Explorations below the 2,000-meter mark have indicated that large quantities of the minerals are present, but as of 1990 no actual extraction had been undertaken.