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Mine Water and the Environment

, Volume 37, Issue 2, pp 336–345 | Cite as

Water and Sand Inrush During Mining Under Thick Unconsolidated Layers and Thin Bedrock in the Zhaogu No. 1 Coal Mine, China

  • Yanchun Xu
  • Yaqi Luo
  • Jianghua Li
  • Kunqi Li
  • Xuchu Cao
Technical Article

Abstract

Raising the upper boundary of coal mining under thick Cenozoic unconsolidated layers has brought new challenges to the prediction and prevention of water and sand inrush from overlying sand and gravel aquifers in north China. The mechanism of water and sand inrush was studied based on an incident that occurred at working face 11071 in the Zhaogu No. 1 coal mine, in Henan Province. Geological and hydrogeological investigations in overlying strata indicated that intersections of horizontal confined aquifers and inclined bedrock surfaces, defined as skylight areas, allow water and sand from the aquifers to enter the workings. Geotechnical and physical simulation tests on overlying strata showed that mining-induced fractures in weathered bedrock were gradually enhanced by water and sand flowing under high pressure, leading to inrush incidents at the working faces. The empirical formula for estimating the requisite size of coal and rock pillars were modified by incorporating a term for protective thickness under skylight areas. The modified formula was successfully applied to the extraction of neighboring faces, proving its applicability in coal mines with similar geological and hydrogeological conditions.

Keywords

Coal mining Water hazard Skylight areas Fracture evolution in mudstone Coal and rock pillars 

Untersuchung eines Wasser- bzw. Sandzulaufs in die Zhaogu Nr. 1 Kohlemine (China) während der Abbauführung unterhalb von mächtigen unkonsolidierten Einheiten bei geringmächtigem Deckgebirge

Zusammenfassung

Die Erhöhung der hangenden Abbaugrenze unterhalb mächtiger unkonsolidierter känozoischer Sedimente in einem Kohlebergbau in Nord-China führte zu neuen Herausforderungen bei der Vorhersage von und Vorbeugung vor Wasser- und Sandeinbrüchen aus überlagernden kiesig/sandigen Grundwasserleitern. Die Mechanismen von Wasser- und Sandzutritten werden anhand eines Fallbeispiels aus der Zhaogu Nr. 1 Kohlemine (Henan Provinz, Ortsbrust 11071) untersucht. Geologische und hydrogeologische Untersuchungen der überlagernden Einheiten zeigten, das Kreuzungsbereiche von flach lagernden, gespannten Grundwasserleitern mit einfallendem Gebirgsbereichen, hier „skylight areas“ genannt, einen Zutritt von Wasser und Sand in die Grubenbaue begünstigten. Geotechnische und physikalische Simulationstests der überlagernden Einheiten lassen vermuten, dass bergbauinduzierte Kluftzonen im verwitterten Gebirge unter dem Einfluss der unter hohen Drücken auftretenden Wasser- und Sandflüsse sukzessive erweitert worden sind und somit einen Zufluss in die Grubenbaue begünstigten. Ein empirischer Ansatz zur Berechnung der Kohle- und Gesteinspfeilermaße wird in dieser Untersuchung durch einen zusätzlichen Term zur Beschreibung der notwendigen Mindestmächtigkeit unterhalb von „skylight areas“ erweitert. Die modifizierte Formel konnte erfolgreich bei Nachbarabbauen angewendet werden. Dies zeigt, dass solche Ansätze beim Kohleabbau unter ähnlichen geologischen Voraussetzungen verwendet werden können.

赵固一矿(中国)厚松散层薄基岩采矿条件下突水溃沙

摘要

厚新生代松散层下提高煤炭开采上限为上覆砂砾含水层突水溃沙预测和防治提出新挑战。基于河南赵固一矿11071工作面突水溃沙案例研究突溃机理。地质和水文地质条件分析表明,水平含水层与倾斜基岩面交线为含水层水、沙溃入工作面的天窗。覆岩岩石力学和物理模拟试验表明,高压下水沙流使风化基岩采动裂隙扩展,导致突溃发生。通过增加天窗区保护厚度项,修正了煤岩柱尺寸计算经验公式。修正公式已成功应用于相邻工作面,证明了相似地质和水文地质条件下方法的适用性。

Inundación de agua y arena durante los trabajos mineros bajo capas gruesas no consolidadas y lecho rocoso fino en la mina de carbón Zhaogu N° 1, China

Resumen

La elevación del límite superior de la minería del carbón bajo gruesas capas cenozoicas no consolidadas ha traído nuevos desafíos a la predicción y prevención de la irrupción de agua y arena desde los acuíferos de grava y la arena superior en el norte de China. El mecanismo de la entrada de agua y arena se estudió en base a un incidente que ocurrió en la superficie de trabajo 11071 en la mina de carbón Zhaogu No 1, en la provincia de Henan. Las investigaciones geológicas e hidrogeológicas en los estratos suprayacentes indicaron que las intersecciones de los acuíferos confinados horizontales y las superficies rocosas inclinadas, definidas como áreas de tragaluz, permiten que el agua y la arena de los acuíferos ingresen al funcionamiento. Las pruebas de simulación geotécnica y física en estratos suprayacentes mostraron que las fracturas inducidas por la minería en el lecho de roca erosionada se agrandaron gradualmente por acción del agua y la arena que fluían a alta presión, lo que provocó incidentes en las superficies de trabajo. La fórmula empírica para estimar el tamaño requerido de los pilares de carbón y roca se modificó incorporando un término para un espesor de protección debajo de las áreas del tragaluz. La fórmula modificada se aplicó con éxito a la extracción de caras vecinas, lo que demuestra su aplicabilidad en minas de carbón con condiciones geológicas e hidrogeológicas similares.

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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  1. 1.School of Resources and Safety EngineeringChina University of Mining and TechnologyBeijingChina
  2. 2.Mine Safety Technology BranchChina Coal Research InstituteBeijingChina

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