This folder contains correspondence and other documents relating to Edison's ore milling technologies and to surveys of mining properties in Norway. There are a few items by Edison, but most of the correspondence is by Theodore Lehmann, an experimenter and mining surveyor who evaluated ore at the Dunderland Mine with Henry Louis, professor and consulting engineer. Other correspondents include Edward H. Beazley, secretary of EOMS. Some of the letters propose the use of Edison's crushing machinery in the diamond industry. One letter pertains to the hematite and phosphorous content of ore. Also included is a report by the directors of EOMS to its members.

Approximately 60 percent of the documents have been selected. The unselected material includes letters from Edison to Herman E. Dick and James Coats that appear in Thomas A. Edison Papers, Part III (1887-1898).