Nov. 5 (Bloomberg) -- Cia. Siderurgica Nacional SA, Brazil's third-biggest steelmaker, said its iron ore unit Nacional Minerios SA will invest $2 billion as part of a plan to double sales and more than triple production by 2015.

CSN, which last month agreed to sell a 40 percent stake in Nacional Minerios to a group of Asian companies for $3.12 billion, forecast the unit's sales will increase to 39 million tons in 2015 from 18.2 million tons in 2009. Production will grow to 33 million tons from 12.8 million tons, CSN said in a filing with Brazil's securities regulator late yesterday.

About $1.2 billion of the planned investment in Namisa, as the iron ore unit is known, will go to two pellets plants with capacity to produce 12 million tons a year. Namisa will invest $700 million in a concentrator plant for iron ore purchased from the Casa de Pedra mine and $100 million to expand production capacity using Namisa's own mining assets.

CSN, based in Rio de Janeiro, estimates Namisa's reserves at 600 million tons.

Namisa's production cost is $10 per ton and may reach $22 with transportation, according to the statement. The total cost goes down to $18 per ton for ore bought from Casa de Pedra mine and range from $20 to $40 per ton when Namisa buys the ore from third parties, CSN said.

To contact the reporter on this story: Fabiola Moura in New York at fdemoura@bloomberg.net

Last Updated: November 4, 2008 21:04 EST