This folder contains correspondence relating to operations at the ore concentration plant at Dunderland. Also included are items pertaining to Edison's cement works at Stewartsville, New Jersey; problems with slag cement; and the foreign marketing of storage batteries. Most of the letters are by Edison and William Simpkin, his former draftsman. As an engineer for the Standard Construction Corp., Ltd., Simpkin was responsible for executing Edison's designs at Dunderland.

Approximately 70 percent of the documents have been selected. The unselected material consists of letters of transmittal regarding payments to Edison as a director of EOMS.