John Hays Hammond Sr.

John Hays Hammond (March 31, 1855 – June 8, 1936) was an American mining engineer, diplomat, and philanthropist. He amassed a sizable fortune before the age of 40. An early advocate of deep mining, Hammond was given complete charge of Cecil Rhodes' mines in South Africa and made each undertaking a financial success.

He was a main force planning and executing the Jameson Raid in 1895. It was a fiasco and Hammond, along with the other leaders of the Johannesburg Reform Committee, was arrested and sentenced to death. The Reform Committee leaders were released after paying large fines, but like many of the leaders, Hammond escaped Africa for good.

He returned to the United States, became a close friend of President William Howard Taft, and was appointed a special ambassador. At the same time, he continued to develop mines in Mexico and California and, in 1923, he made another fortune while drilling for oil with the Burnham Exploration Company.