Research on Control Technology of Roof-Cutting and Roadway Protection for Narrow Pillar Beneath Close-Distance Goal  
[PERSON]  
1 School of Mines, China University of Mining and Technology, Xuzhou 221116, China; [EMAIL_ADDRESS]  
[PERSON]  
2 School of Energy and Mining Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China; [EMAIL_ADDRESS] (C.L. ); [EMAIL_ADDRESS] (H.L. ); zh98113 [EMAIL_ADDRESS] (H.Z)  
[PERSON]  
2 School of Energy and Mining Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China; [EMAIL_ADDRESS] (C.L. ); [EMAIL_ADDRESS] (H.L. ); zh98113 [EMAIL_ADDRESS] (H.Z)  
[PERSON]  
2 School of Energy Science and Engineering, Henan Polytechnic University, Jiaozuo 454000, China 245000, China 45000, China 45000, China [EMAIL_ADDRESS] (H.Zou, H. Research on Control Technology of Roof-Cutting and Roadway Protection for Narrow Pillar Beneath Close-Distance Goal. _Appl. Sci._**2025**, 15, 2103 10.3390/appl5042103 10.  
seam will form stress concentrations on the lower seam's roof, and the damage to the upper seam's floor and the lower seam's roof will be connected [7; 8; 9]. Consequently, the roadway in close-distance coal seams often experiences problems such as difficult support and large deformation, which seriously affects safe and efficient production in the mine [10]. During the mining of close-distance coal seams, to mitigate the influence of upper-seam mining on the roadway and stope of the lower seam, scholars have conducted in-depth research on the mining layout and surrounding rock control of the lower seam. Regarding the issue of large deformation caused by the high-stress environment of the gob-side entry in the lower seam [11], measures such as staggered arrangement of the roadway [12], roof-cutting and pressure relief [13], and high-strength support reinforcement [14] have been developed. (1) The rational determination of the staggering distance can prevent the dynamic impact of the upper seam's roof caving on the floor, thereby ensuring the safety of the mining operations in the lower seam. [PERSON] et al. [15] carried out research demonstrating that staggered arrangement can effectively prevent and control rock bursts on the goat side during the mining of thick coal seams. [PERSON] et al. [16] analyzed the better layout of the retracement channel and the reinforcement-support scheme for the channel in the close-distance lower seam. For the coal pillar mining in the lower seam, a reasonable pillar-distance needs to be set in accordance with the mining influence of the upper seam, to prevent the large amount of extrusion damage on the pillar side of the gob-side entry [17]. (2) The roof-cutting technology can precisely control the main roof's fracture position through two-dimensional shaped-charge blasting, which enables active control of the pressure [18; 19]. [PERSON] et al. [20] investigated the roof pre-splitting technology for gob-side entry retention and analyzed the roof fracture mechanism. Prior to roof-cutting, the main roof's stress was transmitted to the adjacent roadway or working face via the pillar, leading to severe mining pressure. Once the roof-cutting is implemented, the original stress transfer path is altered, and mining pressure is effectively diverted to the goat. This reduces the stress in the adjacent roadway near the goat, thereby decreasing the stress during gob-side entry driving [21; 22]. Simultaneously, the roof's fracture position after roof-cutting has also changed and is prone to collapse, thus avoiding the rock compression on the coal pillar in the rear goaf [23]. Therefore, the intensity of the lagging mining pressure has also been correspondingly alleviated [24; 25]. Moreover, the key technologies involve different roof-cutting angles, hole depths, hole spacings, and hole layouts. Precise roof-cutting can effectively reduce the roof's lateral cantilever length [26].