Extent of available data.
This data layer indicates the location of underground mine shafts in the Cuyuna Range. It was developed by the Natural Resources Research Institute. Shafts are vertical or inclined passages from ground surface to underground orebodies that allow access/egress of people and materials and provide for mine ventilation and dewatering. They have been digitized from all found and geo-rectified maps of the Cuyuna Range underground natural iron ore mines. This information can be used for mapping, documentation, potential energy storage exploration (pumped hydro, compressed air), monitoring, analysis, and land use planning purposes.