Properties and Application of Backfill Materials in Coal Mines in China

Jixiong Zhang,Meng Li,Abbas Taheri,Weijian Song,Zhongya Wu,Weiqing Zhang

doi:10.3390/min9010053

Jixiong Zhang, Meng Li + Show 4 more

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https://doi.org/10.3390/min9010053

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Abstract

Coal is the basic resource underpinning energy generation in China, however, constant, large-scale mining of coal results in many problems such as ecological destruction of mining areas. As a result, backfilling of solid waste underground is proposed to control strata and surface subsidence and to protect the environment. At present, these materials, such as granular material, cemented material and high-water-content materials are mainly used for backfilling. This study summarised the types of backfill materials that are used in coal mines in China along with the backfilling process. Moreover, distribution and characteristics of mines backfilled with these backfill materials were obtained and analysed. Considering the socio-environmental aspects that affect backfilling, this research proposed a guideline for the selection of backfill materials and then analysed specific engineering cases of three backfill materials. In addition, the future development of backfill materials was discussed. With extensive extraction of shallow coal resources in China and, therefore, rapid depletion of coal resources in eastern regions of China, coal mining depth is increasing significantly. As a result, it is required to investigate new backfill materials suited for the deep high-stress environment.

Highlights

While supporting socio-economic development, the constant large-scale mining of coal resources causes many problems, such as the ecological destruction of mining areas and accelerated depletion of resources (Figure 1) [1,2]
The purpose of this study is to introduce the backfill materials that are used in coal mines in China and summarise the backfilling methods
Physico-mechanical characteristics of backfill materials have been widely been applied in Chinese coal mines

Summary

Introduction

While supporting socio-economic development, the constant large-scale mining of coal resources causes many problems, such as the ecological destruction of mining areas and accelerated depletion of resources (Figure 1) [1,2]. The general handling method is to discharge and accumulate the gangue on the surface in gangue dumps. Gangue dumps occupy land resources and pollute the air and underground water and even result in disasters such as landslides and explosions [5,6,7,8]. By using a caving method to handle goafs, the roof loses the support of the lower coal seams [9], subsidence and breakage occur under the self-weight of the strata and the effect of overburden pressure constantly develop to overly the strata, causing surface subsidence, resulting in problems [10,11,12] such as soil and water loss, land subsidence, vegetation dieback, and building collapse

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Conclusion