This folder contains correspondence and other documents relating to mining and ore milling. Included are letters about the use of Edison's ore separation process in California, Edison's involvement with the Nicaragua Canal Construction Co., and the processing of Cornwall iron ore. There are also letters about the business operations of the New Jersey & Pennsylvania Concentrating Works, the New York Concentrating Works, and the Edison Ore Milling Co., Ltd. Some of the letters are requests for information about Edison's ore milling machinery and ore separation process.

Approximately 80 percent of the documents have been selected. The following categories of documents have not been selected: routine requests for information about ore milling; routine correspondence regarding freight rates for ore shipments.

Related documents can be found in D-93-48 (West Orange Laboratory).