Table 1 List of basic situation of drilling holes.
From: Surface damage reduction effect of ultra-high working face in Shangwan coal mine
Number | Termination depth | Quality | logging depth | Beginning date | Completion date | Loose layer | Bed rock | Fracture zone |
|---|---|---|---|---|---|---|---|---|
SD1 | 187.43 m | A grade | 186.70 m | 2018.09.19 | 2018.09.24 | 69.6 m | 98.5 m | |
SD2 | 177.25 m | B grade | 164.70 m | 2019.03.5 | 2019.03.17 | 44.4 m | 83.6 m | 46.8 m |
SD3 | 182.52 m | B grade | 174.80 m | 2019.03.19 | 2019.03.27 | 41.4 m | 74.3 m | 72.0 m |
