The diameter of the water inlet is about 150 to 200mm of the mining water gun, the diameter of the nozzle is usually about 38 to 150mm, the pressure head is 50 to 150mm. The water consumption is between 1.7 and 14 times than the sand pump mining quantity, in the high mountain areas where is lack of water, it is controlled under 3 times. The minimum distance between water gun and working surface is generally similar to the height value. The moving step nozzle of water gun is between 4 and 6m, and the moving step nozzle of the sand pump is between 50 and 200m. Or move the slime dam ahead after the suction pipe length of sand pump expanded to 50 to 90m, then moving the sand pump.
Hydraulic mining usually does not suit for cold region. In the region with the temperature is lower than 5℃ should take some measures to cold-proof, such as prevent colding of the water pump, sand pump and water pipe. Installed sluice gate at the bottom of the pipe to draw off the water when it stops working. And there should be equipped spare pipe, using the measures to reduce the water to improve the water pressure to 50~60% and so on.
There are four kinds of mining method, reverse, lateral, consequent and joint mining method, reverse mining method is used the most widely. This method is pointing the water gun to the working surface, cutting undermine at the bottom of the step by using jet flow to make sand soil collapse and mixed with water into pulp, then reverse flow towards to the slurry pool and ore groove which can use of the jet velocity fully and reduce water consumption. Because of part of the residual ore cannot be recycled, when there is crack or cavity at the bottom of the stope, and there are some ore deposits, the ore loss rate is generally from 5 percent to 10 percent.
Loose sands can improve the efficiency of water gun of sand pump to reduce the consumption of hydropower and mining cost. The method of loose consists of masonite and water pressure method. The former is used more widely, the economic effect is better, especially in the high mountain where is lack of water significantly, the consumption of per water can be decreased to 1.7t. The latter is suitable for the mine with permeability, and inserting a row of steel tube from the top line 2~3m, about 2 meters deep, distance between pipes is about 3 meters, press into high pressure water.
The method of residual ore recovery, some residual ore formed by the slope of the bottom, and some residual ore is the mine which left in Karst Cave.
All of these above are the methods to mine of sand pump, it will be useful for you.