From the 1850s on he published over 200 articles, several books, and numerous newspaper and mining magazine columns or short pieces on mining and geology. He served throughout his long career as a mining consultant for mining corporations in every western state and several foreign countries, including Japan. He also served as special ambassador for the nascent science of geology while serving as the United States' principal geologic exhibit commissioner for what now would be called World Fairs, from Paris in 1867, through Vienna and the centennial at Philadelphia, back to Paris in 1878. He ended his long and distinguished career as head of the school of mines at the University of Arizona, 1895–1905, remaining in an active emeritus status until his death.