1. The workers remove soil from the bottom of the river and put it on a special table.
2. The soil is "washed" with pressurized water to move sand or other light materials. The heavier materials, such as gold, remain in a carpetlike material attached to the table.
3. Mercury is used to separate the gold from the other heavy objects.
4. They combine the mercury with the other left over objects and burn the whole thing.
5. The mercury then becomes a gas and contaminates the river, plants, and humans.
This process is still used today at the Rio das Velhas.
