On a balsa, a floating pontoon, suction hoses with a diameter of between 4’’ and 8’’ are used to suck up the gold containing material from the riverbed. This is done manually by divers and powered by diesel motors. The material is processed on a sluice box on the pontoon.
A draga is the same as a balsa, except for the fact that the hoses are mechanically driven, and no diver is needed. Dragas are bigger than balsas.