Introduction
It has long been recognized that the largest mineral deposits contain most of the known mineral
endowment (Singer and DeYoung, 1980). Sometimes called giant or world-class deposits, these
largest deposits account for a very large share of historic and current mineral production and
resources in industrial society (Singer, 1995). For example, Singer (1995) shows that the largest
10 percent of the world’s gold deposits contain 86 percent of the gold discovered to date.
Many mineral resource issues and investigations are more easily addressed if limited to the
relatively small number of deposits that contain most of the known mineral resources. An
estimate of known resources using just these deposits would normally be sufficient, because
considering smaller deposits would not add significantly to the total estimate. Land-use planning
should treat mainly with these deposits due to their relative scarcity, the large share of known
resources they contain, and the fact that economies of scale allow minerals to be produced much
more cheaply from larger deposits. Investigation of environmental and other hazards that result
from mining operations can be limited to these largest deposits because they account for most of
past and current production.
The National Mineral Resource Assessment project of the U.S. Geological Survey (USGS) has
compiled a database on the largest known deposits of gold, silver, copper, lead, and zinc in the
United States to complement the 1996 national assessment of undiscovered deposits of these
same metals (Ludington and Cox, 1996). The deposits in this database account for
approximately 99 percent of domestic production of these metals and probably a similar share of
identified resources. These data may be compared with results of the assessment of
undiscovered resources to characterize the nation’s total mineral endowment for these metals.
This database is a starting point for any national or regional mineral-resource or mineralenvironmental
investigation.
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First posted November 19, 1999
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