Drilling efficiency is not only related to the correct choice of cemented carbide grades, but also affected by many factors, mainly Tapered Bit's drill bit shape, rock hardness, blasthole diameter and blasthole depth compression, powder discharge method, air pressure, etc.
Bit shape
 
The shape of the drill bit directly affects the section of the blasthole. The blasthole section of most bit rock drilling is polygonal rather than round. Therefore, the polygonal cross-section is formed due to the fact that the drill bit is pressed to the side of the gun limit when it rotates along its own axis. During rock drilling, the drill rod does not rotate on a fixed axis, but swings freely in the blasthole. This situation can be seen in actual supply as long as you observe carefully. The shape of the drill bit is different, and the cross section of the blasthole obtained when drilling rock is also different.
 
Rock performance
 
The rock properties that affect the drilling speed are mainly viscosity, hardness and elasticity. The viscosity of a rock is its ability to resist breaking into small pieces. The viscosity of the rock is related to the composition and composition of the rock; the size and shape of the particles; the amount, composition and moisture content of the cement. Dense and homogeneous rocks have the same viscosity in all directions, and heterogeneous or layered rocks have different viscosity in all directions. The hardness of the rock is the same as the viscosity, which is determined by the connection force between the rock particles. However, the hardness of the rock is the ability to resist the penetration of sharp tools. The elasticity of a rock refers to its ability to restore its original shape and volume after the external force acting on the rock disappears. All rocks are elastic. The elasticity of the rock has a significant effect on impact drilling.
 
 
Rock dust removal
 
When percussive rock drilling, the formation of rock dust accumulation in the blasthole will greatly reduce the supply rate of the rock drill, especially when the rock drill is drilled vertically or inclined downwards, if the accumulated rock dust is not removed in time, it will increase repeated crushing and reduce Drilling speed. There are two main methods for removing rock dust from the blasthole: the blowing method and the washing method. The blowing method will increase the amount of dust in the air, which is harmful to the health of workers in underground operations. Now underground operations have been banned. The common method is to rinse with water. This method can not only effectively remove rock dust, but also increase the speed of rock drilling, increase the wear resistance of rock drilling tools and significantly improve working conditions. Using this method can ensure that the dust content in the well is below 0.2 mg.
 
Blasthole diameter
 
Increasing the diameter of the blasthole reduces the drilling speed per unit time. By reducing the diameter, the drilling speed can be increased. When the blasthole diameter is increased from 40 mm to 60 mm, the drilling speed is more than doubled. On the other hand, as the diameter of the blasthole increases, a large-diameter drug bag must be used accordingly. The increase in the diameter of the cartridge can also increase the utilization rate of the blasthole, the explosive can be completely detonated, and the content of toxic nitrogen oxide in the blast bankrupt is reduced. According to the test, a 40mm cartridge is used instead of the standard cartridge. When other blasting conditions are the same, the blasthole on the working surface can be reduced by about 33.3%, the blasthole utilization rate can be increased by 15%, the consumption of blasting materials can be reduced by 42%, and the consumption of explosives Reduce by 13%.
Small-diameter drill bits have been tested and promoted in some mines for a period of time, and some results have been achieved to varying degrees, but they have not been fully promoted. The most commonly used drill bit diameter is still 40-43 mm, and the diameter of individual mines is 46 mm.
 
Blasthole depth
 
The depth of the blasthole has a very significant influence on the tunneling speed and the operating cycle time. The depth of the blasthole increases and the drilling speed decreases. When the blasthole reaches a certain depth, the impact energy loss of the drill rod increases due to the increase of the elastic deformation of the drill rod and the friction of the blasthole wall. Changes in the depth of the blasthole cause changes in the drilling speed. It is different in rocks of different hardness. In harder rocks, it has little effect. Generally speaking, when the compressed air pressure is sufficient, the blasthole depth is below 3 to 3.5 meters, and the rock drilling speed does not change much. According to the test, in different rock heads, when using the cemented carbide Drill pipe bit to drill the rock, the test results of the blasthole depth and the rock drilling speed.
 
Compressed air pressure
 
Compressed air pressure has a great influence on rock drilling speed. As the compressed air pressure decreases, the relative supply rate of the rock drill decreases accordingly.
 
The working pressure of the 01-30, 01-45, 01-38 and YT-25 types of rock drills currently used in our country's supply should be above 5 atmospheres to ensure normal operation. Many mines have adopted measures to increase wind pressure to increase rock drilling speed. However, the general wind pressure is preferably between 5 and 8 atmospheres. If it is too high, the damage to the parts of the rock drill and the air pipe will increase. If the pressure is lower than 5 atmospheres, the drilling speed will drop significantly. According to the test, the minimum compressed air consumption during rock drilling is 7 atmospheres, and the work consumed per unit length of the blasthole is the minimum at 6 to 6.5 atmospheres.