Gold placer characteristics in marine sediments of Bayah, West Java, Indonesia

Placer gold deposits in marine sediments in Indonesian waters, especially in Bayah southwest of Java Island, Banten Province, have many characteristics. In Bayah coastal waters, gold mostly accumulates in very fine sands and is associated with magnetic minerals. Elsewhere, coarser sand and gravel sediments tend to have higher Au contents. Gold exploitation in marine sediments has begun with a trial carried out in the coastal water of Bayah using local fishing boats. The successful trial has required pumping of large volumes of bottom sediments onto the deck of a cargo ship with 13.103 tonne capacity that are then stockpiled and processed. Laboratory studies reveal that secondary gold is mostly silt-sized flakes (0.002–0.05 mm).