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Mine Water and the Environment

, Volume 38, Issue 4, pp 817–826 | Cite as

Feasibility of Modifying Coal Pillars to Prevent Sand Flow Under a Thick Loose Layer of Sediment and Thin Bedrock

  • Zhongbo Yu
  • Shuyun ZhuEmail author
  • Yunzhang Guan
  • Dongxiang Hu
Technical Article
  • 37 Downloads

Abstract

This paper focuses on the first work face under a thick loose layer of sediment and thin bedrock in the No. 8 Mining District of the Baodian Coal Mine in the Yanzhou mining area of China. Due to mining, the hydrogeological conditions in the aquifers at the bottom of the thick, loose sediment layers have been greatly changed in the shallow areas in this area. The main problem is a low-pressure, water-rich aquifer. However, this problem could be remedied by modifying the coal pillars to prevent sand flow instead of water seepage. To do so, measurements of the first work face were obtained from drilling data, and the stress distribution and plastic zone were determined by examining the mining of the upper part of the no. 3 coal seam using FLAC3D numerical analysis software. The simulated results were also compared with the empirically calculated results. Comprehensive analysis indicates that modifying the coal pillars from preventing water seepage or inrush to preventing sand flow appears feasible, and provides an important reference for increasing mining areas and recovery of coal resources.

Keywords

Numerical simulation First work face 

Machbarkeit einer Mächtigkeitsmodifizierung der Hangendschutzschichten zur Verhinderung von Sandeinbrüchen im Kohlebergbau unterhalb mächtiger Lockersedimente bei geringer Überdeckung

Zusammenfassung

Gegenstand dieser Arbeit sind Untersuchungen aus dem Abbaudistrikt Nr. 8 des Baodian Kohleabbaus im Yanzhou Bergbaugebiet in China, wo sich der oberste Abbaubereich unterhalb relativ mächtiger lockerer Sedimentlagen befindet. Aufgrund des Bergbaus haben sich die hydrogeologischen Bedingungen in den Grundwasserleitern an der Basis der Lockergesteinsüberlagerung stark verändert. Der an der Lockergesteinsbasis verbreitete ergiebige Grundwasserleiter weist aktuell nur geringe Wasserdrücke auf. Aufgrund der geänderten Randbedingungen werden die Anforderungen an die Hangschutzschichten, welche zukünftig Sand- statt Wasserzufläufe verhindern sollen, untersucht. Zur Ermittlung der Spannungsverteilung wurden Messungen aus Bohrungen der obersten Abbaubereiche verwendet. Mit Hilfe der numerischen Analysesoftware FLAC3D wurden plastische Bereiche oberhalb des Kohleflözes Nr. 3 identifiziert und die Simulationsergebnisse mit empirischen Berechnungen verglichen. Umfangreiche Analysen zeigen, dass es möglich ist, die Hangendschutzschichten, welche Wasserzuflüsse verhindern sollten, so zu modifizieren, dass sie künftig Sandeinbrüche verhindern. Die Untersuchungen können als Referenzbeispiel genutzt werden, um Abbaubereiche zu erweitern und die Kohleressourcen intensiver zu nutzen und abzubauen.

Viabilidad de modificar pilares de carbón para evitar el flujo de arena bajo una capa gruesa de sedimentos y roca delgada

Resumen

Este documento se enfoca en la primera cara de trabajo debajo de una gruesa capa de sedimento y roca delgada en el Distrito Minero No. 8 de la Mina de Carbón Baodian en el área minera de Yanzhou en China. Debido a la minería, las condiciones hidrogeológicas en los acuíferos en el fondo de las capas de sedimentos han cambiado mucho en las áreas poco profundas de esta área. El principal problema es un acuífero rico en agua y de baja presión. Sin embargo, este problema podría remediarse modificando los pilares de carbón para evitar el flujo de arena en lugar de la filtración de agua. Para ello, las mediciones de la primera cara de trabajo se obtuvieron a partir de los datos de perforación mientras que la distribución de la tensión y la zona plástica se determinaron mediante el examen de la extracción de la parte superior del no. 3 vetas de carbón utilizando el software de análisis numérico FLAC3D. Los resultados simulados también se compararon con los resultados empíricamente calculados. Un análisis exhaustivo indica que parece factible modificar los pilares del carbón usados para evitar la filtración o la irrupción de agua para evitar el flujo de arena y proporciona una referencia importante para aumentar las áreas mineras y la recuperación de los recursos de carbón.

修改煤柱防止厚松散层薄基岩下采煤溃砂的可行性

抽象

研究以兖州(中国)鲍店煤矿厚松散层和薄基岩覆盖的八采区首采面为对象。由于煤炭开采,区内浅埋厚松散层底部含水层的水文地质条件已经发生很大变化。主要问题是低压、富水含水层。但是,该问题可以通过修改煤柱达到防止突砂目的,而不是煤柱防止渗(突)水。为此,通过钻孔资料获取首采面尺寸数据,利用3煤顶板FLAC3D采动模拟确定首采面应力分布和塑性区。比较了模拟结果与经验计算结果。综合分析表明,防止渗水或突水的煤柱修改为防止突砂煤柱是可行的,研究对增大开采面积和提高煤炭回采率具有重要意义。

Notes

Acknowledgements

This research was supported by the Fundamental Research Funds for the Central Universities (No. 2015XKMS035), National Natural Science Foundation of China (41727801, 41741020), and the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD).

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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  • Zhongbo Yu
    • 1
  • Shuyun Zhu
    • 1
    Email author
  • Yunzhang Guan
    • 2
  • Dongxiang Hu
    • 2
  1. 1.Institute of Mine Water Hazards Prevention and Controlling Technology, School of Resources and GeosciencesChina University of Mining and TechnologyXuzhouChina
  2. 2.Yanzhou Coal Mine Co., Yankuang GroupZouchengChina

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