Table 5 Design param of exploratory boreholes for 6# and 7# coal seams.
workface | Hole number | Azimuth/° | Inclination/° | Final hole horizon | Design the hole depth/m | Final pore aperture/mm |
|---|---|---|---|---|---|---|
1602 | observation hole 1 | 97 | 61 | Approximately 20 m above the WCFZ | 102.5 | 75 |
observation hole 2 | 110 | 65 | Approximately 20 m above the WCFZ | 98 | 75 | |
observation hole 3 | 110 | 61 | Approximately 20 m above the WCFZ | 103 | 75 | |
comparison 1 | 277 | 61 | Approximately 20 m above the WCFZ | 102.5 | 75 | |
1702 | 1# | 61.8 | 65.7 | 120 m above the 7# coal seam | 123.0 | 94 |
2# | 61.8 | 68.1 | 120 m above the 7# coal seam | 121.7 | 94 | |
3# | 61.8 | 43.8 | 120 m above the 7# coal seam | 62.8 | 94 | |
4# | 321.3 | 65.8 | 120 m above the 7# coal seam | 121.3 | 94 |
