Amar Lai’s first memories are working alongside his parents and siblings in a quarry, breaking rocks. He was aged four.

Now chatting to Lai, a confident 25-year-old human rights lawyer, it is hard to believe he was once a child labourer.

The southeastern Brazilian state of Minas Gerais owes its name to the main economic activity throughout its history: mining – of gold since the 17th century and later iron ore, which took on an industrial scale with massive exports in the 20th century.