Dozens have been reported missing after a mining disaster in Brazil led to two dam bursts and devastated a nearby village.

The town on Bento Rodrigues was hit the hardest, leaving more than 600 people homeless, at least 11 dead and another 15 missing. The sludge has continued on for 440 kilometers downstream, affecting two states and 635 municipalities devastated in its wake.

According to The Age, the exact cause of the dam burst has not been established yet -- although it seems that fingers are pointed at the state's inadequate mining regulations. Mine owners BHP and Vale, as well as operator Samarco, have also been pointed to be the cause of the problem, as they're believed to have failed diligence and responsibilities noted in the OECD guidelines.

The Minas Gerais state environment prosecutor said, "This is no accident. It is a mistake in operation and negligence in the monitoring."

Among the negligent acts committed by the company included concerns about the integrity of the dam when assessed by the Brazilian organization Instituto Pristino.

ABC has reported, however, that Samarco and BHP already spoke of the tragedy. Speaking at the shareholder's meeting, BHP Billiton chairman Jac Nasser said, "We are deeply sorry for all those who have been impacted by this tragedy, in particular for the friends and families of those who died and those who are missing, as well as those who have lost their homes and feel uncertain about the future." He also added that the BHP has committed $363 million to rebuild properly following the tragedy.

Nasser explained, The emergency response team evacuated over 600 people and provided them with temporary accommodation. Samarco has provided affected communities with water and food."

However, not everyone is accepting mere apologies. A lot of questions were raised for Mr Nasser and the rest of the companies. Sally Rugg from GetUP said, "BHP have some really serious questions to answer about this enormous mining disaster, one of the biggest environmental disaster the world has ever seen."

She added, "Why was nothing done in 2013 when a report was put to Samarco about the dam's instability? Why would the dam not have an alarm system that would have warned people in their homes to evacuate before they were hit with 60 million cubic metres of waste."

Greenpeace is also in Brazil to document what's happening and member Nikola Casule has shared, "We are working closely with those communities to get the justice that they deserve, the amount of compensation are clearly far less than what is required."