TUCURUI, Brazil — Old-timers here remember when they would meet in the middle of the river, in dugout canoes, and trade machetes and cloth for diamonds with suspicious, painted Indians carrying bows and arrows.
Now, out of the white mists that swirl at dawn over the green jungle, the sun rises from behind a massive concrete barrier. The Tucurui Falls are gone, and in their place stands a two-mile-long hydroelectric dam that spans the Tocantins River.
The Indians are virtually gone from the river, which now reeks of dead fish. The main group of them, the Parakana, have seen their numbers sharply reduced by disease. Since contact was first made with them in 1970, when the dirt road called the Transamazon Highway was being surveyed, their population has dropped to 200 from an estimated 300. The survivors are supposed to live in a still-undefined reservation.
But the newcomers to the river are well installed. On a height overlooking the dam stands the modern town of Tucurui, with 6,000 residences, a hospital, schools, supermarkets, social clubs, banks, a jet airport and direct-dial telephone service to all of Brazil.
The town was built for the power station's staff by Electronorte, the Brazilian state company that built the dam and will develop power at other sites in the Amazon region. Tucurui, the first high dam on the Amazon river system, is a symbol of a new era of massive projects and modern technology in what has been Brazil's most underdeveloped region, which has the potential to produce 100,000 megawatts.
The last decade has seen torrential tropical rivers harnessed by dams and spanned by railway and highway bridges. The new transportation systems are bringing out huge mineral resources in iron ore, bauxite for aluminum, manganese, copper, tin and gold. The electricity powers ore smelters and industries based on the region's mineral, forestry and agricultural potential.
When the water of the Tocantins began turning the first two generators in November, 1984, 600,000 kilowatts of electricity were immediately transmitted to power new aluminum plants installed at Belem, 200 miles to the north, and at Sao Luiz, farther east in the state of Maranhao.
As power output increases to the rated capacity of 3,900 megawatts for the first stage of the dam, Tucurui will supply electricity over a 1,200-mile transmission line to the power system covering northeast Brazil. When a second powerhouse is installed, probably by 1990, Tucurui will become the world's third-largest hydroelectric site, producing 8,000 megawatts. No. 1 is the Itaipu, on the Parana River between Brazil and Paraguay, and No. 2 is the Grand Coulee on the Columbia River in the United States.
$5-Billion First Stage
The first stage of Tucurui, which received $2.5 billion in financing from the French government, cost nearly $5 billion. It is only one of the major projects installed in the eastern Amazon state of Para, where state and private investments totaling $15 billion are leading the onslaught on the Amazon's riches.
Behind the dam, which rises 250 feet from the river bed, there is a lake that covers 976 square miles, about twice the area of Los Angeles. The waters have submerged a virgin forest with thousands of acres of valuable timber that could not be removed because of the urgency of the project.
At the head of the lake is the old river town of Maraba, which has become a booming commercial center since a railroad bridge was completed this year across the Tocantins. This span links the interior of Para with the coast over a 550-mile electrified railway that is advancing a mile a day toward the world's largest deposit of high-grade iron ore at Carajas.
The recently discovered Carajas mineral district, 200 miles southwest of Tucurui, contains in the folds of its forest-covered hills a variety of ores comparable in size and variety to the most famous mines of South Africa, Canada and Australia.
"The discovery of the Amazon mineral structures since serious exploration began in the late 1960s is what justifies the power projects and lays the basis for the industrialization of the region," said Breno dos Santos, a Brazilian geologist who found the Carajas iron deposits in 1967 while working for U.S. Steel Corp.
World's Largest Iron Exporter
Dos Santos is now the chief of the Amazon exploration program of Companhia Vale do Rio Doce, the Brazilian state company that is already the world's largest single exporter of iron ore.
Vale do Rio Doce is developing the Carajas district with an initial investment of about $3 billion in an iron mine, designed to begin exporting 15 million tons of ore in 1986, and the railroad to the shipping terminal at Ponta de Madeira, six miles east of Sao Luiz.
Manganese is already being trucked over a 125-mile paved road to Maraba, where it is put on railroad cars, along with lumber and other cargo, for the trip to the coast. Copper deposits estimated at 10 million tons have been found.