The 15th International Mineral Processing Symposium took place in Istanbul, Turkey, on October 19-21, and gathered more than 250 participants. Dr. Drelich was invited plenary speaker. Beside the plenary lecture entitled Surface Charge Heterogeneity of Minerals: Why do We Need to Study it?, he also presented a paper entitled Meaningful Contact Angles in Flotation Systems: Personal Inclination. He was invited by his collaborator from Istanbul, Prof. M.S. Celik. This visit also provided great opportunity to meet former SURFI scholars, Mr. Onur Guven (currently Dr. Guven) and Ms. Dilek Senol-Arslan.