Selection of rock drilling tools for underground mines and roadway excavation
Demand for rock drilling tools
The rock drilling tool chain is the last link in the entire rock drilling system. The entire drilling tool system includes: shank, connecting sleeve, drill rod and drill bit.
The whole drilling tool system requires precise processing technology and ideal processing tolerance, so that the whole system can have better quality and rock drilling performance. Likewise, the entire system, including the drilling rig, rock drill and drill system, needs to be adjusted appropriately for the particular rock drilling conditions and application. The entire rock drilling tool system needs to meet the following requirements:
1. High-speed drilling characteristics.
The modern hydraulic rock drill provides powerful and unparalleled power for rock drilling tools. rock drill
During the working process, the tool is subjected to strong compressive stress, tensile stress, thread wear, friction and heat, and
Erosion from rocks.
2. Requirements and characteristics of drilling tool materials.
In the above complex situation, the material of rock drilling tools is required to have four characteristics.
(1) Robustness.
To achieve minimum energy loss and ideal drilling verticality, the drilling tool material is required to have good robustness
and reasonable drilling tool size.
(2) Fatigue strength. During the working process of the drilling tool system, the
If the rate is subjected to extreme compressive stress and tensile stress, the drill is required to have extremely high fatigue resistance.
(3) High strength. Working under high-power rock drills requires the drilling tool system to have extremely high strength, so as to minimize the possibility of drilling tool breakage.
(4) High wear resistance. For rock drilling tools, high wear resistance ensures thread
have a higher lifespan. The alloy part of the drill is particularly demanding. The above four properties of rock drilling tools are not positive, or even negative.
3. Drilling characteristics.
In the process of downhole rock drilling, important drilling characteristics mainly include the following aspects.
(1) Drilling diameter. The selection of the aperture needs to comprehensively consider the size of the roadway, the specifications of the drilling rig, and the power of the rock drill.
rate, hole depth, blasting method and rock hardness. In summary, the choice of aperture mainly needs to consider:
The number of holes in the working face, the number of blasting required, the drilling accuracy and the particle size of the rock breaking, the roadway support
requirements, the requirements for the quantity of shotcrete.
(2) The depth of the hole. Before designing and arranging holes, it is necessary to comprehensively consider the depth of drilling. achieve drilling depth
And the ideal balance of rock drilling shifts, it is also necessary to comprehensively consider rock conditions, work plans and shift arrangements.
In roadway operations, one of the most important objectives is to achieve maximum single roadway footage.
(3) The verticality of the hole. Likewise, there are many factors that affect the verticality of a borehole. achieve higher production
Force, drilling accuracy are as important as drilling speed. Therefore, the quality of drilling is related to drilling per hour
The number of holes is equally important. Ideal vertical hole for better blasting efficiency. Drilling deviation
The deviation from the whole is due to the misalignment of the hole, the poor opening of the hole and the deviation due to the rock condition. The right drill can make the most
Minimize deflection during drilling.
4. Slag discharge.
Efficient drilling speed is inseparable from effective slag removal effect, on the contrary, it will reduce the life of drilling tools and accelerate.
Wear and tear of rock drilling equipment, reduce drilling speed and drilling accuracy. In short, if effective slag removal cannot be achieved, the
The economics of this operation will be greatly reduced.
5. Reaming.
During the drilling and blasting operation of the roadway, the diameter of 64-127 mm is usually used in the center part.
cutout holes. In the actual operation, the small hole 35--45 mm will be drilled first to ensure the accuracy of the cutting hole.
and reduce the consumption of drilling tools. The main purpose is to obtain the space for blasting expansion in advance to achieve better blasting effect and effective depth.
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