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Full-Text Articles in Engineering
Techniques For Prevention And Control Of Ordovician Limestone Water Disasters Based On Modified Water Inrush Coefficient Method, Li Kai, Li Xiaolong
Techniques For Prevention And Control Of Ordovician Limestone Water Disasters Based On Modified Water Inrush Coefficient Method, Li Kai, Li Xiaolong
Coal Geology & Exploration
There are technical problems in preventing and controlling Ordovician limestone water disasters during mining above ultra-thin aquifuges, such as those of the lower coal group in Weibei Coalfield. At Sangshuping Coal Mine, horizontal directional drilling technology was used to develop water prevention and control ideas of Ordovician limestone top utilization and grouting transformation. Firstly, considering the loss of water resistance in the floor failure zone, the water inrush coefficient method was used to determine the critical thickness of Ordovician limestone top utilization and grouting transformation. The directional drilling exploration was carried out by drilling from the two opposite ends of …
Powder Discharge Characteristics Of Pneumatic Double Pipe Directional Drilling In Broken Soft Coal Seams And Its Application, Nie Chao, Wang Yi, Yao Yafeng, Hong Jianjun
Powder Discharge Characteristics Of Pneumatic Double Pipe Directional Drilling In Broken Soft Coal Seams And Its Application, Nie Chao, Wang Yi, Yao Yafeng, Hong Jianjun
Coal Geology & Exploration
To study the influence of casing, casing bit size and casing rotational speed on pulverized coal discharge in double pipe directional drilling technology, three kinds of casing and casing bits in different sizes are designed respectively against the background of pneumatic double pipe directional drilling in the broken soft coal seam, the changes of the discharge rate and outlet velocity of pulverized coal under different combinations are analyzed, and the influence law of different casing rotational speeds on the suspension rate and conveying trajectory of pulverized coal are obtained. The numerical simulation results show that the ø120/96 mm casing with …
Study And Application On Multi Branch Point Sampling Drilling Technology Of Coal Seam Floor Borehole, Chu Zhiwei, Long Weicheng, Jia Bingyi, Liu Fei
Study And Application On Multi Branch Point Sampling Drilling Technology Of Coal Seam Floor Borehole, Chu Zhiwei, Long Weicheng, Jia Bingyi, Liu Fei
Coal Geology & Exploration
According to the technical requirements of long-distance gas parameter measurement, gas extraction borehole design guidance, and extraction evaluation for broken soft coal seam, the multi branch point sampling drilling method of coal seam floor borehole was proposedand its sampling drilling process was formulated on the basis of analyzing existing problems of sampling and drilling technology. Furthermore, the key drilling technologies such as accurate drilling trajectory control and “mechanical + hydraulic” efficient slag removal were developed. The equipment of drilling and sealed sampling were introduced. The application test was carried out in a coal mine in Suzhou, Anhui Province, in which …
Resistivity Detection And Its Application In Underground Coal Mine Directional Boreholes, Li Bofan, Liu Lei, Fan Tao, Jiang Qiping, Wang Jie
Resistivity Detection And Its Application In Underground Coal Mine Directional Boreholes, Li Bofan, Liu Lei, Fan Tao, Jiang Qiping, Wang Jie
Coal Geology & Exploration
The working face threatened by high gas or Ordovician limestone water pressure generally adopts directional drilling technology to carry out fracturing or grouting works at the bottom of the working face before mining to ensure the safety of mining. In-hole probing in directional boreholes in the bottom plate can reveal the hidden structures in the working face in a more detailed way, and can also realize “one hole for multiple uses”. In order to solve the detection problem in the directional drilling, a method of DC resistivity detection in the horizontal directional drilling is proposed. To solve the problem of …