Digital geologic maps of the US states with consistent lithology, age, GIS database structure, and format

Aerial surveys of magnetic anomaly and gamma ray emission; older surveys were analog record which have been digitized, newer surveys collected data in digital form.

National Mineral Resource Assessment 1998: Estimates of the number of undiscovered mineral resources of gold, silver, copper, lead, and zinc within identified permissive tracts (geographic areas in which mineral deposits may form).

Seventy-seven major components of the North American continent were delineated at a general scale (1:5,000,000); including the general composition, geological environment, and types of primary metals endowments that can be expected in each domain.

A compendium of references to previously published databases and database records that describe PGE, nickel, and chromium deposits and occurrences. These data show where to obtain more detailed information about each deposit or occurrence.

Symbols indicating mining-related features digitized from historical USGS topographic maps in the western part of the conterminous US. Includes prospect pits, mine shafts and adits, quarries, open-pit mines, tailings piles and ponds, gravel and borrow pit