What's the difference between i.e. and e.g.?
A surface deposit of minerals, such as gold or magnetite, laid down by a river. The minerals are usually concentrated in one area because they are relatively heavy and therefore settle out of the river's currents more quickly than lighter sediments such as silt and sand. ◇ The extraction of minerals from placers, as by panning, washing, or dredging, is called placer mining.