Extent of available data.
This data layer indicates the locations of underground caved areas within the Mesabi Range. It was developed by the Minnesota Department of Natural Resources using the documented outlines of underground caved areas as denoted on historical mine maps of the Mesabi Range. It was created to document outlines of underground caved areas that could not be included in the Mesabi Range Underground Mine Workings layer because the features could not be enclosed into polygons. It should be used in conjunction with the aforementioned layer for a complete representation of underground workings for mapping, documentation, monitoring, analysis, and land use planning purposes.