This folder contains correspondence regarding the business of the Edison Iron Concentrating Co. Most of the letters are by Walter S. Mallory, secretary-treasurer and general manager of the company. Some of the documents pertain to production difficulties at the company's ore milling plant in Humboldt, Michigan, which was destroyed by fire on December 3, 1890. There are also letters about the survey of mining properties, the distribution of stock, and other financial matters.

Approximately 70 percent of the documents have been selected. The following categories of documents have not been selected: routine correspondence regarding stock assessments, orders, and shipment of equipment; letters of transmittal; duplicate copies of selected items; documents that duplicate information in selected material.