Uranium
Uranium has been sought in Illinois by many people in recent years. The Geological Survey also carried out a wide search for uranium and particular attention was paid to certain clays and other rocks in Hardin County and certain black shales in other parts of the state.
About 200 samples from Hardin County and 175 samples of the shales were tested by the Survey. No deposits were found that are known to be of the required richness and quantity.
Iron Ore
About the middle of the 19th century two furnaces in Hardin County in extreme southern Illinois for a time produced iron from local limonite ores. The ore is said to have occurred as pellets, chunks, and masses scattered through soil and clay and apparently was of irregular distribution. Little can be seen of the deposits today. Their extent is not known, but they are believed to be of limited size.
The Illinois State Geological Survey carries on a continuous program of research on the industrial minerals and metals of Illinois and their uses.
In addition to the investigations mentioned in this booklet, many others have been made or are in progress. Such studies are necessarily a continuing activity if the full potentialities of Illinois mineral resources are to be realized, for industry continually demands new raw materials and changes its requirements for those now used.
The Survey has issued numerous reports that deal with the resources discussed here and mimeographed lists of these are available upon request.
If reproduction is made of the material herein, acknowledgment of the Illinois State Geological Survey is requested.