Notes:

This map layer includes refractory, abrasive, and other industrial minerals operations in the United States. The data represent commodities covered by the Minerals Information Team (MIT) of the U.S. Geological Survey, and the operations are those considered active in 2003 and surveyed by the MIT. This is a revised version of the June 2004 map layer.The data is legacy and not expected to be updated. It is being provided as the best available until Mineral Resources identifies an alternative data source.