**Takashi Sasaoka 1, Pisith Mao 1,2,\*, Hideki Shimada 1, Akihiro Hamanaka <sup>1</sup> and Jiro Oya <sup>3</sup>**


Received: 28 July 2020; Accepted: 3 September 2020; Published: 10 September 2020

**Abstract:** The present research primarily focuses on the investigation of gate-entry stability of longwall trial panel under weak geological condition in Indonesia coal mine by means of numerical analysis. This work aims at identifying appropriate roof support at 100 m and 150 m of depth during gate development. Due to depth depending competency of dominant rock, the stability of gate-entry at 100 m of depth can be optimized by leaving at least 1 m of remaining coal thickness (RCT) above and below the gate-entry. The appropriate support for the trial panel gate-entry is steel arch SS540 with 1 m and 0.5 m spacing for 100 m and 150 m of depth, respectively. The influence of panel excavation on gate-entry is also discussed. Regarding the aforementioned influence, the utilization of additional gate mobile support is recommended at least 10 m from the longwall face.

**Keywords:** longwall mining; weak geological condition; gate-entry stability; remaining coal thickness
