John Potts (1760-1809) was a Pennsylvania businessman and member of the Potts family of ironmasters. This collection documents copper and iron ore mining and land speculation in Pennsylvania and Virginia by John Potts Jr. between 1767 and 1830. The bulk of the collection consists of correspondence between Potts and his brother-in-law, Robert E. Hobart (1768-1826). It describes the initial operation of the Keeptryst Furnace and the operations of the Copper Mine Company of Pennsylvania.

Thomas Ellwood Gillingham, Jr. (1912-2004) was a geologist, he worked as an independet consultant and for the Atomic Energy Commission and the W.R. Grace & Company. The collection documents Gillingham's career as a geological consultant. The collection is arranged into six series: W.R. Grace & Co.; Uranium Mining; Phosphate Mining; Reports; Education; and Reference cards.

The Tonopah Mining Company of Nevada was incorporated on July 12, 1901 in Delaware for the purpose of developing and operating a gold and silver ores property at Tonopah, Nevada. One aerial photograph showing small mineral mining operation at Gowanda on Miller Lake, Ontario, Canada.

The majority of the records for the parent company consist of correspondence, both incoming and outgoing, primarily generated by or for company officers and/or directors.