1. The relationship between roof shallow crack channel and drilling signals.
- Author
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LIU Hong-tao, ZHAO Zhi-qiang, FAN Long, WANG Fei, and ZHANG Hao
- Subjects
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DRILLING & boring , *COAL mining , *SANDSTONE , *STATISTICAL correlation , *MUDSTONE - Abstract
Taking roof shallow strata as the research object, the field test research on the drilling feedback signal of variable thrust level in drilling construction process and the characteristics of drill deep-drill speed, the results showed that in drilling area drilling speed and thrust level are approximate linear positive correlation. As lithology different its drill speed growth rate is different. In blocking of the mudstone layer the drill speed is negative growth. Under 2.5-3.5 kN thrust level, the drilling speed in the coal seams, mudstone layer and sandstone layer decreases in turn. The coal seam roof of test coal mine is in the drilling area. The average drilling speed is 41. 8-43. 2 mm/s, fluctuation is -4.07% -3.01% ; The average drilling speed in sandstone is 8. 4-9. 8 mm/s, fluctuation is -16.3% -19. 0% ; The average drilling speed in mudstone is 22.4-23.5 mm/s, fluctuation is -28.1%-24.3% ;The integrity of roof mudstone is poor, there is a fissure channel in each range of 1. 1-1.3, 2.7-2.8 and 4. 1-4. 4 m, the fluctuation of drilling speed in channel is up to 122.3%; the characteristic curve of drilling depth-drilling speed can clearly characterize the location of fissure channel. [ABSTRACT FROM AUTHOR]
- Published
- 2013