(Adds comments from consultancy, Samarco)

RIO DE JANEIRO, Nov 3 (Reuters) – The "socio-environmental" damage brought about by the 2015 rupture of a tailings dam in Brazil owned by miner Samarco is between 37.6 billion reais ($6.73 billion) and 60.6 billion reais, according to a study done by a company contracted by prosecutors to measure the costs of the disaster.

The study, carried out by consultancy Lactec at the request of Brazilian federal prosecutors, was seen by Reuters this week. Its conclusions come as Brazilian authorities, Samarco and Samarco co-owners BHP Group and Vale SA enter the final phases of a re-negotiation of a 2016 settlement related to the disaster.

The dam collapse near the town of Mariana killed 19 people and severely polluted the Rio Doce river, compromising the waterway all the way to its outlet in the Atlantic Ocean.

"We did an environmental valuation and we're giving a base to prosecutors so they have a reference point with which to make future decisions," said Renata Cristine da Silva Gonçalves, a researcher at Lactec.

"We don't have any way to define what prosecutors will do with the results of the study," she added.

Samarco told Reuters it would comment on the matter as soon as possible.

($1 = 5.59 reais)

(Reporting by Marta Nogueira; Writing by Gram Slattery; Editing by Aurora Ellis)