Inside the world's largest iron ore mine
19 June 2012 Last updated at 09:30 BST
In the heart of the Amazon rainforest, the Carajas mining complex is a series of vast man-made chasms, extracting iron ore around the clock.
The owners, the Brazilian company Vale, say they are operating the mine in a sustainable way and will restore the landscape and trees.
Conservationists fear the digging is causing lasting damage.
Our science editor David Shukman and cameraman Tony Fallshaw were given special access to the mine.