Ricardo Castroviejo, Professor Emeritus of Mineralogy and Ore Geology at the Superior School of Mines, Technical University of Madrid, has over 40 years of research and teaching experience in Mineral Raw Materials. He has been a postgraduate fellow, visitor or invited professor in Heidelberg, Nancy, Sao Paulo, Reno (Nevada), Lima, Bochum, etc. After completing his PhD (1974), he worked on industrial projects for more than 10 years before joining the university in 1987. He has over 150 publications on the Mineralogy and Genesis of Ore Deposits, Mining Exploration and Geometallurgy, with an emphasis on Ore Microscopy, to his credit.