John Ridley is the Malcolm McCallum Chair of Economic Geology at Colorado State University where he has taught ore deposit geology and field geology for the past seven years. His earlier academic positions spanned three other continents, with positions at universities in Australia, Switzerland and Zimbabwe, and over his career he has taught courses in geochemistry, petrology and structural geology. Professor Ridley has published over seventy articles in refereed journals and books, in addition to geological maps and reports for companies and groups within the mining and minerals industries.