Measurement of overburden failure zones in close-multiple coal seams mining

• 作 者: Yang Li Yuqi Ren Syd S.Peng Haozhou Cheng Nan Wang Junbo Luo
• 机 构: School of Energy and Mining Engineering,China University of Mining and Technology (Beijing),Beijing
• 出 处: 矿业科学技术学报（英文版）
• 发表日期: 2021年1期
• 关键词: Overburden measurement GPR survey Close multiple coal seam Secondary roof break

In the Kaiping Coalfield, mining of five coal seams, located within 80 m in the Kailuan Group, #5, #7, #8, #9 and #12 coal seam, is difficult due to small interburden thickness, concentrated stress distributions, high coal seam metamorphism, and complex geological conditions. By using the ZTR12 geological pene-tration radar (GPR) survey combined with borehole observations, the overburden caving due to mining of the five coals seams was measured. The development characteristics of full-cover rock fractures after mining were obtained from the GPR scan, which provides a measurement basis for the control of rock strata in close multiple coal seam mining. For the first time, it was found that the overburden caving pat-tern shows a periodic triangular caved characteristic. Furthermore, it is proposed that an upright trian-gular collapsed pile masonry and an inverted triangular with larger fragments piled up alternately appear in the lower gob. The research results show that the roof structure formed in the gob area can sup-port the key overlying strata, which is beneficial to ensure the integrity and stability of the upper coal seams in multiple-seam mining of close coal seams.