Production restarted late-March in three more pellet plants thanks to signs of a pickup in Chinese demand, Brazilian mining giant Companhia Vale do Rio Doce (RIO) said Tuesday.

The three plants are run by Samarco Mineracao S.A., a Vale joint venture with BHP Billiton (BHP).

Vale said it was currently operating just three of its nine wholly-owned iron ore pellet plants: Tubarao 1, Kobrasco and Vargem Grande.

Vargem Grande, a new seven million metric tons a year plant, started up at the end of March, producing just 4,000 tons.

According to Vale's quarterly output report released Tuesday, pellet production fell 73.4% to 2.885 million tons in the first quarter of 2009, compared to the year-ago quarter.

-By John Kolodziejski, Dow Jones Newswires; 55-21-2586-6086; John.Kolodziejski@dowjones.com