The Bureau of Mines mineral industry location system (mils) is part of the computerized minerals availability system (mas), a comprehensive data base of known mineral deposits. Mils, the location subsystem of mas, has become widely used by the minerals industry and organizations with land-use planning and land management responsibilities. Information on more than 135,000 mineral locations and processing plants in the United States is contained in the data base. This information includes the name, location, mineral commodity, type of operation, bibliography, and cross-references for each property or prospect. Computer-drawn map overlays at various scales showing clustered mils locations and computer printouts keyed to those overlays are available for inspection and reproduction at the Bureau's field operations centers at Juneau, Alaska, Denver, Colorado, Pittsburgh, Pennsylvania, and Spokane, Washington.