赵固二矿露头区砂砾含水层下安全煤岩柱留设研究

Safety Coal and Rock Pillar Design for Mining under Gravel Aquifer in Outcrop Area of Zhaogu 2nd Mine

赵固二矿煤层隐伏露头区域工作面开采受到新近系下层砂砾含水层的威胁,原设计中采用分层开采,工作面产量和效率难以提高,经济效益低。通过对现场实测、FLAC3D数值模拟以及对类似地质条件矿井综放或大采高综采的覆岩破坏规律进行分析,选取较大的垮采比和裂采比预计"两带"高度,并与综放开采"两带"高度经验公式预计进行对比,采用"最小安全厚度"法选取保护层厚度,最终合理确定了防砂和防水安全煤岩柱的高度以及开采厚度。结果表明基岩厚度较薄的区域可只采顶分层,解放大量浅部煤炭资源,提高采出率;基岩较厚的区域变分层开采为一次采全厚大采高开采,有利于矿井实现高产高效安全开采。

The mining face in coal outcrop area,Zhaogu 2nd Colliery,was threatened by gravel aquifer of Neogene System. Slice mining was selected in former design,but output,efficiency and economic benefit would be limited. By analyzing overlying strata damage rule with on-the-spot observation and FLAC3Dsimulation and referring to full-mechanized caving and large-height mining faces with similar geological condition,selecting larger caving-to-mining ratio and fracturing-to-mining ratio to predict caving and fracturing height,applying minimum safe thickness method to selecting protective thickness,rational height of coal and rock pillar for preventing water and sand,and mining height were obtained. Results showed that only mining top-slice could free large amount shallow coal resource and improve mining ratio in thin basement area,and mining whole coal-seam with large-mining-height method in thick basement area was benefit for realizing high output and high efficiency of mine.