Assessment of undiscovered deposits of gold, silver, copper, lead, and zinc in the United States

Contains the results of a national mineral resource assessment study. Identifies regional tracts of ground believed to contain most of the nation's undiscovered resources of gold, silver, copper, lead, and zinc in conventional types of deposits. Includes probabilistic estimates of the amounts of these resources. Contains a table of the significant known deposits in the tracts, and descriptions of the mineral deposit models used for the assessment.