Original article is only available in Portuguese here. We provide a summary translation here:

…Exhaustive shifts ... that put the health and safety of workers at risk, led the Ministry of Labour and Employment (MTE, in Portuguese) to indict Anglo American, responsible for the Minas-Rio project, and…companies providing services to Anglo-American on an outsourced basis - Milplan, Enesa and Construction Model – for using labour which resembled slavery .... [There are] ... stories…recounted ... by ... victims…who were subjected to up to 200 hours overtime per month ... [the] MTE classified outsourcing to Tetra Tech as “illegal” ... Anglo American ... does not agree with the assessment of MTE ... and will contest the assessment ... "the company informs that it vehemently rejects any resemblance of the situation of these employees to slave labour. The notification was related to overtime practiced that exceeded what the law allows...”,  it said in a statement ... Milplan also stated ... that does not agree with the assessment and will ... defend itself ... Tetra Tech was contacted but it declined to comment. We tried… to contact Model Builder via telephone, but no one answered calls...