Stirred ball mills are being more and more integrated into the automatic processing system. To enhance the safety of the operation and increase the milling capacity, as well as to enable the prediction of the grinding results, it is necessary to understand the processes occurring in the milling chamber. Therefore, it is necessary to relate the optimal operating regime to dependence on the geometry, reactant, and operating parameters. The applicability and reliability of CoBall mills, as a typical representative of annual gap mills, can be determined more precisely by the modeling presented. At the same time, predictions can be made about the flow paths in the grinding gap and the motion of the grinding balls. For given geometries, the local temperature gradients for different inlet flows are discussed.