(Adds mine details, completion, ramp-up schedule, environmental measures)
By Marta Nogueira
RIO DE JANEIRO, Feb 17 (Reuters) - Brazil's Vale SA , the world's largest iron ore producer, said Wednesday that it began testing equipment at its $14.4 billion S11D mine at its massive Carajas complex in the Brazilian Amazon.
The mine is the company's largest ever.
Tests began with the 9.5-kilometer (5.9-mile) conveyor belt that takes iron ore from the mine's open-cut pit to its processing facility, said Jamil Sebe, head of iron ore project implementation for the company's Amazon iron assets.
The mine, which has capacity to produce 90 million tonnes of high-grade ore a year, more than a quarter of the company's current output, will be brought on stream in a way that respects world iron ore supply and demand, Sebe said.
"The project will have 90 million tonnes of capacity when it opens, but Vale wants to administer the ramp-up curve in line with the market," he said.
Iron ore .IO62-CNI=SI, a key raw material for the making of steel, has fallen 30 percent in the last year and 75 percent in the last five years, as growth in China, the world's largest iron ore importer, has slowed. Vale and its two main rivals, Australia's Rio Tinto Ltd and BHP Billiton Ltd , have ramped up output in an attempt to boost market share and drive out smaller, higher-cost producers.
The mine and processing plant are 80 percent complete and Vale hopes to finish the rest by the end of June with production ramp-up beginning in the second half of the year, Sebe said.
The conveyor belt, "the dorsal spine of S11D," was built so the processing plant could be built in a non-forested area. The belt will allow ore to be moved without the giant house-sized, diesel-fueled trucks normally used in open-pit mines.
As a result, S11D will use about 70 percent less diesel and emit 50 percent less greenhouse gasses than a conventional mine.
The mine will also use waterless separation of high-grade ores from waste rock known as gangue.
This will slash water needs and eliminate the need for slurry ponds and tailings dams like the one that burst in November at Samarco Mineração SA, killing at least 17 and polluting hundreds of kilometers of rivers and valleys.
The Samarco tragedy is considered by Brazil's government to be the worst environmental disaster in the country's history.
Samarco is a 50-50 iron ore mining joint venture between Vale and BHP Billiton. (Writing by Jeb Blount; Editing by Chizu Nomiyama and Leslie Adler)