Mining giants BHP and Vale sign a deal with Brazil's government to pay nearly $30 billion in damages for a 2015 dam collapse that triggered the country's worst environmental disaster. President Luiz Inacio Lula da Silva attends the signing of the deal over the November 5, 2015 collapse of a tailings dam at a mine in the southeastern town of Mariana, which triggered a giant mudslide. IMAGES AND SOUNDBITES