Research Article
Critical Height of Unfilled Zone in Underlying Gob Piles
Table 3
Drilling measurement schemes.
| Sequence | Drilling number | Time interval (d) | Monitoring site | Monitoring purposes |
| 1 | 1 | 1∼2 | Surface | Whether the filling body is connected to the roof | 2 | 2 | 3 | 3 | 4 | 5 | 5 | 6 | 6 | 10 | 7 | 13 |
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