Undercover and on high alert, Brazilian "garimpeiros" -- or "prospectors" -- seek to cash in on the country's rich mineral reserves, digging for metals in Canaa dos Carajas. The region is home to an estimated 100 illegal mines, as well as the huge S11D iron-ore mine which has, since opening in 2016, tripled the size of the city of Canaa and made it the richest in Brazil in 2020.