On 18.11.2011, Dipl.-Ing. Hagen Müller (1978), who joined HAVER ENGINEERING Meissen in 2009, was awarded his PhD by Freiberg University of Mining and Technology (Fig.). The dissertation is entitled with “Contribution to the systematic study of washing and refining processes”. Dr. Müller focussed on this subject against the background that washing and refining machines in minerals processing make a major contribution to improving product quality and relieving the load on the downstream process stages. To this end, the currently available machines were classified in a system and compared on the basis of technical and economic characteristics. Fundamental empirical studies culminated in the development of a ring shearing fixture to examine the main machine- and process-related factors influencing the washing process. The determined dependences are key preconditions for plant design and the development of corresponding machine technology. Dr. Müller now devotes his attention to these objectives in his work at HAVER ENGINEERING Meissen.