Application of gas drainage technology and equipme

2022-10-19
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Application of gas drainage technology and equipment in large diameter and long boreholes

for a long time, gas disasters have been affecting the safety production of coal mines. Especially in high gassy mines, gas control is not only costly, but also often restricts the production of coal mines because it cannot be connected with raw coal production in time. Therefore, high gassy mines strive to ease the contradiction between production and gas prevention and control through efficient drainage technology and advanced equipment, and improve the economic benefits of coal mines

coal seam gas drainage by drilling is a commonly used and effective method in China at present. It has the characteristics of fast construction speed and flexible drilling yard layout. However, due to the small diameter of drilling holes and the small cracks generated in the hole wall, the drainage effect is not as good as that of roadway drainage. By increasing the diameter and number of boreholes and increasing the negative pressure of orifice drainage, we can make up for the shortcomings of the latter, but we must have a complete set of equipment suitable for gas drainage in coal mine boreholes in order to achieve the ideal drainage effect. After years of research, Xi'an Branch of the General Academy of Coal Sciences has successively developed a series of drilling rigs capable of drilling large-diameter holes and their supporting construction technologies, which have been put into high-yield and efficient coal mine production and played an important role in gas prevention and control in high gassy mines

1 development and application effect of large diameter gas drainage drilling rig

Yangquan Mining Bureau is a typical high gassy mine, with poor coal seam permeability, high gas emission from the mining face, and most of it comes from the upper adjacent layer and surrounding rock. In the 1980s, in order to solve the gas problem that restricted the safety production of coal mines, Yangquan Mining Bureau adopted the method of drilling dense small-diameter roof through layer drilling combined with driving a 50m long upward inclined roadway (high drainage roadway) to drain gas, so as to solve the gas problem in the upper adjacent layer. This pumping method not only needs to consume a lot of manpower and material resources, but also takes time for construction and high production cost. It is often not connected with the working face in time, which affects the production progress. Therefore, Yangquan mining bureau put forward the idea of drilling large-diameter gas drainage holes instead of inclined high drainage roadways, and reducing the density and number of small-diameter gas drilling holes with an attitude of excellence. This idea was strongly supported by the safety bureau of the former China National Coal Mine Corporation to organize research and development around the manufacturing needs of Dongguan. On this premise, Xi'an Branch cooperated with Yangquan Mining Bureau to develop mkd-5 drilling rig. The drill is a full hydraulic power head drill, which is composed of the main machine, pump station and console. It has good disassembly, convenient relocation and transportation, and can be flexibly arranged according to the situation of the drilling site. In order to prevent the drill from running when drilling inclined holes and reduce the labor intensity of the drillers, the drill is designed with functions such as clamping and rotating linkage, automatic screwing and unloading of drill pipes, and angle adjustment of hydraulic cylinders. The technical parameters of mkd-5 drilling rig are as follows:

drilling depth: 100M

drill pipe diameter: 73mm

opening diameter: 250mm

final hole diameter: 200mm

drilling inclination: ± 90 °

slewing speed: 10 ~ 320r/min

maximum torque: 1850n · m

energy feeding force: 105kn

lifting capacity: 73kn

process: 600mm

motor power: 30kW

the drill was industrialized in Yangquan No. 3 mine in 1992 The cone bit with a diameter of 215mm is equipped for inspection, and the drill hole with an elevation of 40 ° is drilled to the bottom for 100m Yangquan Mining Bureau also conducted a comparative test of gas drainage in large-diameter boreholes, dense small-diameter boreholes and rock strike roadways. See Table 1 for the comparison of pumping technical indicators

Table 1 Comparison of several drainage technical indicators

drainage

mode

spacing between boreholes or roadways/m

gas volume of working face/m3 · min-1

effective drainage

drainage distance/m

adjacent layers

drainage rate/%

return air

tailways

drainage

small holes

10

3.14

20.67

10.06

7

32.73

small holes

7

4.18

9.51

14.52

7

60.42

rock roadway

200

3.50

6.47

17.54

230

72.24

rock roadway

<200

2.91

8.62

27.73

205

76.28

macropore

140

6.26

11.16

28.29

128

has been in a relatively slow development situation for a period of time in the past 71.71

macropore

70

3.65

4.78

11.98

21 0

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