Brazilian prosecutors will decide in the coming weeks whether to lodge criminal charges against Samarco and its executives for last November's deadly dam burst at its iron ore mine at Fundao.  Samarco, which is jointly owned by BHP Billiton and Vale, denies wrongdoing.

"The task force is at this moment concluding the analysis of the documents from the investigation," prosecutor Eduardo Santos de Oliveira said in an interview, declining to comment further on what charges might be brought or whether the case might be dismissed.

This comes after a report says the dam burst was caused by human error in the form of design flaws in the dam that was supposed to hold back mining waste, known as "tailings".  Instead, the dam walls collapsed and about 60 million cubic meters of iron waste flowed into the Doce River, burying the town of Bento Rodriguez at a cost of 19 lives.  It is one of Brazil's worst environmental disaster, if not the worst.

"There was a fundamental change in the design concept whereby more widespread saturation was allowed and accepted," the report said, adding "this increase in the extent of saturation introduced the potential for sand liquefaction."