Replay:Impact crushers involve the use of impact rather than pressure to crush material. The material is contained within a cage, with openings on the bottom, end, or side of the desired size to allow pulverized material to escape. This type of crusher is usually used with soft and non-abrasive material such as coal seeds, limestone, gypsum or soft metallic ores. There are two types of impact crushers: horizontal shaft impactor and vertical shaft impactor.