This folder contains correspondence and other documents relating to mines and ores to be bought, sold, worked, or tested. Some of the letters deal with the mining interests of individuals and companies who either wanted to sell property to Edison or to have their ores tested. There are also inquiries regarding Edison's ore separation process. At the end of the folder is a 9-page list of mining properties in New Jersey, with annotations by Edison.

Approximately 30 percent of the documents have been selected. Most of the selected letters received a significant reply by Edison.