(Adds tonnage of iron ore exports blocked at Vale port)
RIO DE JANEIRO, Jan 22 (Reuters) - Moody's placed the credit ratings of Brazilian iron ore miner Vale SA under review for possible downgrade to "junk" status on Friday, one day after it put nine mining companies in Latin America on review for downgrade due to low metals prices.
Moody's said slowing growth in the Chinese economy, which consumes half the world's base metals and is the world's largest consumer of iron ore, is weakening demand and prices for some of Vale's principal products.
Vale is the world's largest iron ore exporter.
"China's outsized influence on the commodities market, coupled with the need for significant recalibration of supply to bring the industry back into balance indicates that this is not a normal cyclical downturn, but a fundamental shift that will place an unprecedented level of stress on mining companies," Moody's wrote in a statement announcing the ratings review.
The price for Chinese-landed iron ore <.IO62-CNI=SI>, which makes up the bulk of Vale's revenue, is trading at its lowest level in more than a decade.
Vale's Baa3 rating on its long-term foreign-currency debt is only one step above a non-investment grade, or junk, rating. Were Vale to be downgraded, many investment funds would be prohibited from owning its debt because they are restricted to holding only investment-grade securities.
This could raise Vale's borrowing costs as it struggles with lower iron ore revenues and faces a rising wave of environmental costs.
On Thursday, Brazil's government said it was nearing an estimated 20-billion-real ($4.8 billion) accord with Samarco Mineração SA to repair damage from a deadly November iron ore tailings dam burst.
Samarco is a 50-50 joint venture between Vale and Australia's BHP Billiton Ltd, and the government said it expected Vale and BHP to guarantee the financing for the Samarco clean-up, which could last a decade.
Also on Thursday, a federal court in Brazil's Espirito Santo state ordered the closing of the iron ore and coal terminals at Vale's Port of Tubarão, which moves about 35 percent of Vale's iron ore and is one of the world's largest iron ore terminals.
The port closure has halted the loading of some 200,000 tonnes of iron ore per day, the company said in a Friday statement. It is also blocking access to 44,0000 tonnes per day of coal imports that supply much of Brazil's steel industry.
If the facility is closed for more than four days, Vale will have to stop mining at many of its major mines in Minas Gerais for lack of storage space for ore, Leonardo Shinohara, mining analyst with HSBC in Sao Paulo, said in a client note.
(Reporting by Jeb Blount in Rio de Janeiro and Reese Ewing in Sao Paulo; editing by Jason Neely and Meredith Mazzilli)