The traditional placer mining, in the form of gold panning, is the most used type of gold prospecting, and has survived until the 21st century, though the number of prospectors dropped. Wooden and modernized plastic pans are used. It takes an estimated of sand and sludge to be filtered in order to obtain of gold, if gold is present in the deposit brought by the river as the deposits of gold are at the depth of . Discovered gold nuggets are mostly small with some larger recorded from , with the largest recorded nugget having .