Inertia ore milling equipments fall into two types according to the nature of work: the coarse crushing type and the medium and fine crushing type. Basing on the structure and function, the inertia ore milling equipment are divided into the suspension type, the shaft type and the vibrating type. Take the rotary crushers for coarse crushing as an example, the operating mechanism consists of movable cone and fixed cone. The to-be-crushed ores in the crushing cavity will be pressed down to the fixed cone from the movable cone. Though the volume and floor space are large, the production and efficiency are high. Consequently, it is mainly applied for first crushing. The movable cone gear plate is the wear part. Therefore, the discharge port adjustment and the liners replacement are relatively inconvenient. As a result, it is of necessity to configurate automatic discharge port adjustment device. Thus, the hydraulic ore milling equipmentcomes into existence as required. The remarkable difference lies in that the hydraulic cylinder is installed on back-up ring at the main shaft suspension point or at the bottom of the main shaft for supporting the main shaft. The discharge port adjustment is relatively convenient for the hydraulic rotary ore milling equipments owing to the controllable cylinder pressure. The inertia ore milling equipment is designed and manufactured by introducing advanced technology from abroad and considering the actual application conditions at home. The equipment belongs to the high efficiency energy saving tertial crusher type with high crushing ratio and production efficiency. Compared with the traditional ore milling equipments, it is outstanding due to many features. Firstly, it achieves material layer crushing, which reduces power consumption for unit crushing ratio; secondly, it realizes flexible granularity adjustment, improving the product quality; thirdly, it simplifies the process with the optimized structural design; fourthly, it is capable of getting rid of hard materials, ensuring the reliable operation of the process and holding the equipment in a safe and steady state.