Numerical and theoretical investigations of the effect of the gangue-coal density ratio on the drawing mechanism in longwall top-coal caving

International Journal of Coal Science & Technology

Zhengyang Song¹  Yinchao Yang²  Dongliang Cheng³  Weijie Wei³  Jinwang Zhang³  Zhaolong Li⁴ 

[1] Coal Industry Engineering Research Center of Top-Coal Caving Mining;Jizhong Energy Group;State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology–Beijing;Yichun Luming Mining Co., Ltd.;

关键词: Longwall top-coal caving;    Gangue-coal density ratio;    Drawing body;    Top-coal boundary;    Recovery of top coal;   

DOI  :  10.1007/s40789-022-00501-4

来源: DOAJ

【 摘 要 】

Abstract Discrete element calculations of the top-coal drawing process for different gangue-coal density ratios were conducted to investigate the effect of the gangue-coal density ratio on the drawing mechanism in longwall top-coal caving. The effects were analyzed for the drawing body, the top-coal boundary, and the recovery of top coal. The results show that for increasing density ratio, the initial drawing body on the goaf side is farther away from the drawing support and its width and volume gradually increase. The upper part of the sickle-shaped drawing body extends near the initial drawing body with increasing density ratio in the normal cycling stage, and the distance from the drawing body to the initial drawing body is its maximum width. The larger the density ratio, the smaller the height of the top coal above the goaf at the end of the initial drawing process. The height of the top-coal boundary decreases with increasing density ratio, until it reaches a limit. In a normal cycle, due to hysteretic development, the top-coal boundary moves toward the goaf until the density ratio is approximately 2.0, which is consistent with the physical experiment results. Finally, increasing the advance length of the working face is beneficial for increasing the overall recovery of top coal.

【 授权许可】

Unknown