About Iowa Coal Mining and Coal Mine Data

Coal data development

Coal was mined in Iowa for over 150 years, with the earliest recorded mining in the 1840's and the last recorded mining in 1994. Mining was by both surface and underground methods and mines ranged in size from small adits operated during the winter months by a few miners to large shipping mines that provided fuel for the transcontinental railroads. Organized record-keeping began with the implementation of the Office of State Mine Inspectors in 1884. From then until the Mine Inspectors were discontinued in 1973, the Office was responsible for collecting and maintaining maps and other materials. In 1973, those materials were transferred to the Iowa Geological Survey (IGS).

A few years after IGS acquired the materials, problems caused by underground mines prompted efforts on the part of IGS to organize the records and develop a map of Des Moines showing the locations of known mines. Part of that effort included restoration of the mine maps and improvements in the map storage and development of an electronic database. An improved map of Des Moines showing the known mines and maps of What Cheer and Centerville followed.

The adoption of geographic information system technology by IDNR in the late 1980's allowed the development of a digital representation of the known mines as polygons that traced the outlines of mines areas and points for known or approximate locations that lacked a map. Further advances in mapping technology allowed for improved GIS data and the addition of scanned mine map images to the GIS data collection for coal mines. In 2008-2009, the mine maps in the IGS collection were scanned on a large format scanner and in 2011-2012 mines maps (212) for Des Moines and the surrounding area were georeferenced and raster catalogs created. An ArcGIS web service was created and mapping web site created and deployed. In 2015-2016, an additional 650 mine map images were georeferenced and loaded into the raster catalogs. The result made the last known mine map for each mapped mine site available in a file geodatabase or from the Iowa Coal Mines web site.

"Completeness" of coal mine data

Compilations of the data relating to coal mine held by the State of Iowa suggest that as many as 6,000 mines may have operated in Iowa over the State's 150-year coal mining history. Geographic locations derived from a variety of sources have been assigned to 3,071 mines which comprise the data included in the web mapping application. The State's collection includes approximately 1,500 mine maps documenting 876 unique mine sites. The remaining maps are earlier versions, duplicates, or other charts and diagrams. Approximately 700 of the sites are surface mines or underground mines from other map sources that lack the precision of the surveyed maps. Finally, roughly half of the 3,071 located mines are known as point locations only. Although the total number of mines is a very broad estimate, it does suggest that a large number of undocumented mines may be present. This has been demonstrated by field observations and geotechnical studies of problems caused by undocumented mines.

A database was developed early in studies of the coal mine maps and related information to record the characteristics of the map documents, location data, characteristics of the mines, dates, and owner/superintendent names. Most of this information is available through the website or in the GIS data. Items that have not been included are either redundant or have little value for most inquiries about mining, e.g. corner coordinates of the georeferenced maps, map readability, etc.