Report issued by the U.S. Bureau of Mines discussing mining methods of the Rosiclare Fluorspar mine and mill. As stated in the introduction, "the publication covers exploration, development, mining and milling practices, mine-drainage problems, and other activities and is presented as part of the Bureau of Mines series of publications on mining and milling practices in various parts of the United States" (p. 1). This report includes maps, tables, illustrations, and photographs.

From abstract: Pt 1. The present work seems to confirm the genetic theory previously published, namely that [Illinois Cave in Rock] deposits were formed by ascending solutions. These solutions probably followed minor fissures that connected below with larger fissures, which in turn probably connected with a major fault zone. It is believed that where such minor fissures extended upward only to the shale or other impervious cap rock, or were greatly reduced in size where they penetrated such beds, the solutions spread laterally along the contact and along the limestone beds beneath it and replaced the limestone. Pt 2. This report is a presentation of the results of an electrical-resistivity survey conducted in the fluorspar-bearing areas of Hardin County, Ill., principally during the field seasons of 1934 and 1935.