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U.S. Geological Survey
Circular 1178
Online version 1.0


1998 Assessment of Undiscovered Deposits of Gold, Silver, Copper, Lead, and Zinc in the United States

By The U.S. Geological Survey National Mineral Resource Assessment Team


NOTE: A recompilation of this report has been released as Open-File Report 02-198. The recompilation was undertaken to (1) make the data compatible with Microsoft Windows operating system, Macintosh operating system, Linux, and other types of Unix computers; (2) provide a more user friendly browser; and (3) correct a number of errors and numbering inconsistencies in the original Circular 1178.


Color map of U.S. showing geographic regions assessed in this report

This report summarizes the results of the 1998 National Mineral Resource Assessment that estimated the gold, silver, copper, lead, and zinc in undiscovered deposits in the United States. This project also estimated the identified resources and past production of these five metals. Assessment results include the following: (1) It is estimated that 18,000 metric tons (t) of gold, 460,000 t of silver, 290,000 kilotons (kt) of copper, 85,000 kt of lead, and 210,000 kt of zinc are in undiscovered deposits minable with existing technology. (2) In addition, it is estimated that 15,000 t of gold, 160,000 t of silver, 260,000 kt of copper, 51,000 kt of lead, and 55,000 kt of zinc remain in identified resources. (3) Past production from the largest identified resources of gold, silver, copper, lead, and zinc is estimated to be 12,000 t of gold, 170,000 t of silver, 91,000 kt of copper, 41,000 kt of lead, and 44,000 kt of zinc. These deposits account for about 99 percent of cumulative domestic production in the United States.

Download a PDF version of the paper report (1.2 MB) (The original report contains a CD in pocket. This CD contains the data base and browser. The CD can be obtained only by ordering the book. See the address given below.)

Download a free copy of Adobe Reader.

Download compressed data, browser, and all files comprising entire report [Note: 180 MB]

The data base consists of the following:

The browser is a map-based, stand-alone Windows application. The browser allows a user to click on a tract for a selected mineral deposit model type and to display either the tabular data associated with the tract or the rationale that was used to assess the tract. The rationale contains hypertext links to the tonnage and amounts of contained metal in undiscovered deposits, the mineral deposit model type used to assess the particular tract, and the significant mineral deposits associated with the tract. A user can also choose to display the assessment regions, mining districts, and significant mineral deposits, as well as several standard thematic layers such as political boundaries, cities, airports, rivers, and color-shaded relief.

The included browser installs only under Windows 95, 98, or NT operating systems.

This report, including CD-ROM containing all data and the browser, is available from:
USGS Information Services, Box 25286,
Federal Center, Denver, CO 80225
telephone: 303-202-4210; e-mail:

For questions about the content of this report, contact Paul Schruben

Maintained by: John Watson
Last modified: 8-07-09