Emad Ansari - Faculty of Mining, Petroleum & Geophysics Eng., Shahrood University of Technology, Shahrood, Iran.
Ramin Rafiee - Faculty of Mining, Petroleum & Geophysics Eng., Shahrood University of Technology, Shahrood, Iran.
Mohammad Ataei - Faculty of Mining, Petroleum & Geophysics Eng., Shahrood University of Technology, Shahrood, Iran.

Due to longwall mining, a large space without any support is created, and the in-situ stress regimes change. The change of the in-situ stress regimes affects the roof and face of the adjacent panel. In other words, the strata behavior would be different from the intact condition during the previous panel mining. In this study, two adjacent panels are simulated in the FLAC۳D software to study the effect of panel extraction on its adjacent panel strata behavior during longwall mining. The available data of the Tabas Parvadeh Coal Mine panels is used for this purpose. According to the numerical modeling results, the length of the first roof’s weighting effect (FRWE) in the gob of the first and second panels is calculated, respectively, as ۲۶ and ۲۱ meters. In other words, the gob dimension in the second panel is reduced by about ۱۹.۲%, and the vertical displacement value is increased by about ۱۸.۵%. In addition, the chance of roof collapse and face spalling during the first-panel mining is more than the second-panel. It means that roof and face instability in the (FRWE) during the first-panel mining is confirmed, while in the second-panel extraction is just very likely.

Longwall Mining, induced stresses: Strata behavior, Roof collapse, Face spalling