Bedrock

The solid rock underlying unconsolidated surface materials such as soil, alluvium, laterite, or saprolite. In mining, bedrock defines the base of open cut excavations, the host rock for hard rock ore deposits, or the contact below alluvial and lateritic mineral accumulations. In bauxite mining, bedrock represents the lower boundary of the economic ore horizon. In alluvial gold and diamond mining, bedrock is critical as the accumulation surface where heavy minerals concentrate due to density separation in river systems.