A shared borehole approach for coal-bed methane drainage and ground stabilization with grouting. (July 2016)

• Record Type: Journal Article
• Authors: Xuan, Dayang; Wang, Binglong; Xu, Jialin
• Is Part Of: International journal of rock mechanics and mining sciences. Volume 86(2016:Jul.)
• Page Start: 235
• Page End: 244
• Publication Date: 2016-07
• Subjects: Shared borehole approach -- Lag grout injection -- Ground stabilization -- Pressure-relief CBM drainage -- Mining-induced fractures; Rock mechanics -- Periodicals; Soil mechanics -- Periodicals; Mining engineering -- Periodicals; Roches, Mécanique des -- Périodiques; Sols, Mécanique des -- Périodiques; Technique minière -- Périodiques; 624.151305
• DOI: 10.1016/j.ijrmms.2016.04.019
• Languages: English
• ISSNs: 1365-1609

Abstract

Abstract: In underground longwall coal mines, the risks of surface subsidence and coal-bed methane (CBM) emission are generally controlled separately (e.g., subsidence mitigation by overburden stabilization using grout injection, and pressure-relief CBM drainage using surface boreholes); however, some longwall panels require both gas drainage and ground stabilization. For this purpose, we propose a shared borehole approach for ground stabilization grouting and adjacent seam pressure-relief CBM drainage by using mining-induced fractures and voids. In this method, overlying seam pressure-relief CBM is drained through a surface borehole during extraction of a longwall panel, whereas grout injection is applied to stabilize the ground using the same borehole following drainage. A combined drainage–injection model that determines the allowable lag distance for grout injection is proposed. The effectiveness of the shared borehole approach was tested at a longwall panel in a Chinese coal mine. No obvious interactions between the injection and drainage processes were detected during the case study, verifying the effectiveness of the shared borehole approach. Highlights: A shared borehole approach proposed for CBM drainage and grouting. A temporal model combining gas drainage and grout injection is proposed. The proposed approach was tested in a Chinese coal mine longwall panel. Interaction of CBM drainage and injection was tested using a case study.