U.S. investment bank Goldman Sachs, through its unit Colombian Natural Resources SAS, has purchased for $407 million the thermal coal assets of Vale SA, the world's largest iron-ore producer, in Colombia.

Part of the package included Brazilian miner's the Cerro Largo deposit, El Hatillo coal mine, a port facility on Colombia's Atlantic coast as well as an 8.4 per cent control in the Ferrocarriles Del Norte de Colombia railway system that connects the mines with the port, the Rio de Janeiro-based company said in a statement on Monday.

Vale SA sold the thermal coal mines in support of its plan to divert its focus to concentrate on operating and mining coking coal, the basic raw coal commodity used by steel makers. Just last week, Roger Downey, head of Vale's coal operations, affirmed thermal coal is no longer part of the company's "core business."

"The sale of the thermal coal operations in Colombia is part of our continuous efforts to optimise the asset portfolio," Vale SA said in the statement.

"We have world-class, competitive projects that offer us a big growth pipeline" in metallurgical coal, Mr Downey was quoted as saying by Bloomberg News. "Thermal coal is a bit outside our core business, so we need to see our assets in Colombia through that context."

Goldman Sachs' purchase of Vale SA's coal properties reinforces the banks' physical commodities portfolio after buying metals warehousing group Metro International as well as another coal mine in Colombia, both in 2010.

Colombian Natural Resources SAS, a wholly owned unit of Goldman Sachs, jacked up production to 58 per cent in 2011.

Production at Vale's mines jumped 19.4 per cent to 3.57 million metric tonnes in 2011 while Colombian Natural Resources generated a 58 per cent increase to 2.39 million metric tonnes, Reuters reported.