Fine high-pressure water jet mining coal mining and rock-breaking new technology is promising, has entered the industrial pilot phase.
In the United States, a water jet drilling coal mining method was developed. The hole was drilled from the ground to the coal seam. The pipe was placed in the hole, and the high pressure water pipe and the two nozzles were lowered to the bottom of the hole. When the pipe was rotated, the water jet was 315 kg/cm. The coal is broken and the coal slurry is pumped to the ground with a jet pump. West Germany is made up of a hard rock boring machine with 60 nozzles and 14 disc hobs. The nozzle has a diameter of 0.25 mm and a water pressure of 3.920 kg/cm. The boring speed is 50 higher than that of a roadhead without a high pressure water nozzle. -100%. The pulse water jet device developed by the Soviet Union, with a pressure of 10,000 kg/cm, tested 12 square meters of roadway in sandstone and entered 0/4 m per hour.
China's coal mines are also conducting high-pressure water jet tests. As for hydraulic coal mining, it has been applied in China and has achieved some results. Research and development of hydraulic coal mining technology is one of the major projects with long history, wide practice and many lessons learned since the founding of the People's Republic of China. In 1956, China began the hydraulic mining test. The water mining technology has reached a certain scale of production, the process system has been continuously improved, accumulated certain technical experience, and has reached the world advanced level in some aspects.
2 In 1 Angle Rule,Trigonometry Rules,2 in 1 Digital Angle Rule,2 in 1 Digital Angle Scale Ruler
Jinyi , https://www.kingangle-jy.com