Research on the Key Technology of Gob-Side Entry Retaining by Roof Cutting for Thick and Hard Sandstone Roofs

Chaowen Hu (), Eryu Wang (), Qian Li, Yilong Wang, Yongyuan Li and Xingfeng Sha
Additional contact information
Chaowen Hu: Huaneng Coal Technology Research Co., Ltd., Beijing 100070, China
Eryu Wang: School of Mine and Coal, Inner Mongolia University of Science and Technology, Baotou 014010, China
Qian Li: Huaneng Coal Technology Research Co., Ltd., Beijing 100070, China
Yilong Wang: Huaneng Coal Technology Research Co., Ltd., Beijing 100070, China
Yongyuan Li: Huaneng Coal Technology Research Co., Ltd., Beijing 100070, China
Xingfeng Sha: Huaneng Coal Technology Research Co., Ltd., Beijing 100070, China

Sustainability, 2022, vol. 14, issue 16, 1-14

Abstract: In order to ensure the application of gob-side entry retaining by roof cutting for thick and hard sandstone roofs, the key technology of pre-split blasting was studied. The LS-DYNA was used to analyze the blasting effect of the energy-gathering pipe. Using the methods of theoretical analysis and numerical simulation, it was determined that the optimal cutting height was 16 m and the optimal cutting angle was 15°. The effect of pressure relief by roof cutting was verified by FLAC3D. It is proposed to use deep-hole loosening blasting to solve the problem of the sandstone with a thick hard roof being difficult to collapse. A group of loose blasting holes was designed to be arranged every 20 m in the gob-side roadway. The depth of the #1 blasthole was 47 m, and the angle to the horizontal direction was 20°; the depth of the #2 blasthole was 65 m, and the angle to the horizontal direction was 15°. A field test was carried out in the 7135 ventilation roadway of Qidong Coal Mine China. The on-site peeping results showed that the blasting with the energy-gathering pipe had a good effect of directional slitting. After deep-hole loosening blasting, the thick hard sandstone roof collapsed and filled the gob in time. The monitoring curves of the hydraulic support showed that the hydraulic support resistance of the working face in the side with roof cutting was much smaller than that of the side without roof cutting, and the effect of pressure relief by roof cutting was good.

Keywords: gob-side entry retaining; thick and hard sandstone roof; pressure relief by roof cutting; pre-split blasting (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2022
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

Downloads: (external link)
https://www.mdpi.com/2071-1050/14/16/9941/pdf (application/pdf)
https://www.mdpi.com/2071-1050/14/16/9941/ (text/html)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:gam:jsusta:v:14:y:2022:i:16:p:9941-:d:885948

Access Statistics for this article

Sustainability is currently edited by Ms. Alexandra Wu

More articles in Sustainability from MDPI
Bibliographic data for series maintained by MDPI Indexing Manager ().