This map is a scanned and georeferenced image of the Swanson & Son Coal Company. This map represents the last known map
of the mine shown, although it may not represent the full extent of mining. The maps are part of the collection developed
by the State Office of Mine Inspectors and later transferred to the Iowa Geological Survey in 1973 where the maps are currently
held. The map images are stored in TIFF format with world files. Most scans are at 100% of the original map with a resolution
of 200 pixels per inch.