John Jefferson Foster was born in Shelby, Iowa in 1881. His family migrated to Telluride Colorado shortly after where his older brother got a job in the mining industry. John joined his brother shortly after and began working for the Smuggler-Union Mine. John received the nickname Peg-Leg after losing his leg in a mining accident in 1906. This nickname followed him for the rest of his life, even being used as his initials in directors' reports for the company he worked for.

John lived in Chloride with his brothers and first wife Laura during his youth. Chloride, now called Ashcroft, was a mining settlement in Pitkin County that went bust in the early 1900's when richer mines were found in Aspen. Residents began to move away, and the last official resident of the town died in 1939.

John also worked in Pandora, which was a mining town that was part of the Telluride mining district. It quickly became the districts primary milling center and milled products for Liberty Bell and Smuggler Union mine, two of the largest mines in the district.

John later became a surveyor and moved to the Uravan mining district where he helped mine vanadium and uranium for the war effort. He lived there after remarrying Laura and settling down somewhat. Bedrock, Colorado part of the Uravan mining district started as a small agricultural settlement that grew once vanadium, an important element in making steel, was found in the surrounding countryside. Vanadium mining became the principal economic driver of the town until World War II when uranium, which had previously only been sold in small portions as dyes for ceramics, was bought in large quantities by the U.S. government for the development of the atomic bomb. After he retired, he moved to Grand Junction where he remained until his death in 1970 at the age of 88.