A green coal mining method for protecting roadways and overlying strata
Shilin Hou, Manchao He, Jun Yang, Jun Zhang, Yajun Wang, Xuhui Kang, Zijie Han, Fanghui Du
Abstract
The non-pillar mining method with automatically formed roadway (NPM-AFR) is an innovative mining method. This paper provides a detailed description of how this method achieves the cancellation of pillar retention and the advance excavation of roadways through optimized mining processes. Based on mining mechanics modeling, the paper explains how the NPM-AFR compensates for mining-induced damage by utilizing the bulking of the goaf gangue and uses directional roof cutting technology interrupt the stress transmission path from the goaf to the roadway, thereby enhancing the protection of both the overlying strata and the roadway. Geological and mechanical model tests were conducted based on the Ningtiaota coal mine to compare the NPM-AFR and traditional mining method. The results show that under the NPM-AFR, the development height of overlying strata damage is reduced by 36.14% compared to traditional mining method, and overlying strata stress is reduced by 25%. The overlying strata is effectively protected in the NPM-AFR mining area. In both mining methods, the roadways remain in a low-stress zone, but the peak stress on the coal pillar side in the NPM-AFR is reduced by 40.6% compared to the traditional method, significantly reducing the safety risks of the roadway. Field verification tests further demonstrate that the NPM-AFR, along with its supporting processes, successfully achieves the goals of pillar-free mining, surface protection, and safe roadway preservation. This technology represents a sustainable, green mining approach that protects both the overburden and the roadway, providing new solutions for safe and efficient coal mining. • Non-pillar mining method with automatically formed roadway (NPM-AFR) is an innovative mining method. • Reducing overlying strata damage by utilizing the bulking properties of gangue. • Interrupting the roof stress transfer path using directional roof cutting technology. • The NPM-AFR reduces maximum displacement of overlying strata by 36.14% and stress by 25% compared to traditional method. • The NPM-AFR reduces maximum stress of roadway surrounding rock by 40.6% compared to traditional method.