Waterjet medallion-what is waterjet?
Since ancient times, human beings have used the impact of water flow to make hydraulic machinery such as waterwheels and watermills. If water is sprayed from a high-pressure water gun, its impact will be even greater. Used in the coal mining industry in the former Soviet Union, it was called hydraulic coal mining. The high-speed jet of water is blocked by the coal seam, and the speed drops suddenly, and an impact force large enough will be generated in an instant, causing brittle fractures in the coal seam to complete the coal mining operation.