Unconsolidated alluvial deposits, typically sands and gravels, carrying sufficient gold, tin, or gemstones to justify the cost of excavation and water separation. Placer miners distinguish it from barren overburden, stripping away the top layers to reach the concentrated pay zone sitting directly on bedrock.
Heard on the job
The excavator stripped three meters of overburden to get to the washdirt sitting just above the clay layer.
Also heard as
- washing stuff
- pay dirt