Chile's Supreme Court has rejected plans to build a $4.5 billion coal-fired power plant and port to serve northern Chile's copper mines, ruling that the project's Brazilian and German investors failed to prove they can protect the surrounding environment.

Critics said the Castilla project developed by Sao Paulo-based MPX Energia SA would have been one of the most polluting in Latin America. Former President Michelle Bachelet's government turned it down, but after lobbying by Brazilian billionaire Eike Batista, her successor Sebastian Pinera allowed to go forward.

MPX had promised $575 million to mitigate pollution from the plant, which would have produced 2,100 megawatts by 2020, increasing Chile's electricity capacity by more than 10 percent. The court ruled Tuesday after MPX failed to persuade Chileans they could live with the contamination.