Dredging

A method of extracting a placer deposit from a river or sea bed.

This can be performed by a large type of vehicle which can move in shallow water, or a floating
type of boat or barge with machinery that either vacuums or bucket-line/bucket wheels up the
gold-bearing loose sediment from below the water line.

Some specially converted ships are designed to suck up a gold-bearing layer of the sea bed with
their own processing plant onboard.  This creates deeper water for small-scale shipping lanes which
is considered a bonus for the shipping industry.

There have been some concerns regarding this process as silt dispersed below the water line tends to
reduce oxygen levels for marine life.