Upward slicing longwall-roadway cemented backfilling technology for mining an extra-thick coal seam located under aquifers: a case study

Deng, Xu; Zhang, J. X.; Zhou, Nan; Wit, B. de; Wang, C. T.

doi:10.1007/s12665-017-7120-9

Cited by 30 publications

(24 citation statements)

References 41 publications

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“…The main ingredient of LS is calcium oxide, which is an air-hardening cementing material that has a poor cementing capacity in a water environment. The main purposes of adding LS are to excite FA activity [21,22]. Meanwhile, the calcium oxide in the LS can react with the water, thereby consuming free water and reducing the bleeding rate of the slurry.…”

Section: Lime-slagmentioning

confidence: 99%

Influential Factors in Transportation and Mechanical Properties of Aeolian Sand-Based Cemented Filling Material

Zhou

Ouyang

et al. 2019

Minerals

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Given that normal filling technology generally cannot be used for mining in the western part of China, as it has only a few sources for filling gangue, the feasibility of instead using cemented filling materials with aeolian sand as the aggregate is discussed in this study. We used laboratory tests to study how the fly ash (FA) content, cement content, lime–slag (LS) content, and concentration influence the transportation and mechanical properties of aeolian-sand-based cemented filling material. The internal microstructures and distributions of the elements in filled objects for curing times of 3 and 7 days are analyzed using scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). The experimental results show that: (i) the bleeding rate and slump of the filling-material slurry decrease gradually as the fly ash content, cement content, lime–slag content, and concentration increase, (ii) while the mechanical properties of the filled object increase. The optimal proportions for the aeolian sand-based cemented filling material include a concentration of 76%, a fly ash content of 47.5%, a cement content of 12.5%, a lime–slag content of 5%, and an aeolian sand content of 35%. The SEM observations show that the needle/rod-like ettringite (AFt) and amorphous and flocculent tobermorite (C-S-H) gel are the main early hydration products of a filled object with the above specific proportions. After increasing the curing time from 3 to 7 days, the AFt content decreases gradually, while the C-S-H content and the compactness increase.

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Section: Lime-slagmentioning

confidence: 99%

Influential Factors in Transportation and Mechanical Properties of Aeolian Sand-Based Cemented Filling Material

Zhou

Ouyang

et al. 2019

Minerals

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“…These researches revealed that the floor‐strata strain turns from tensile to compression with mining depths increasing . Second, quick‐setting high‐water materials with constant resistance features and paste materials with high strength and low costs were developed to construct roadside backfill. Compared with traditional wooden stacks, intensive individual props, gangue bags, and concrete blocks, these new materials have greater resistance, faster increasing‐resistance, higher filling efficiency, and better sealing effects .…”

Section: Introductionmentioning

confidence: 99%

An innovative approach for gob‐side entry retaining in deep coal mines: A case study

Fan

Liu

Tan

et al. 2019

Energy Science & Engineering

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Due to the complex geostress and mining conditions in the coal seam with depth of 800 m, stability of surrounding rock for gob‐side entry retaining is very difficult to achieve. In this paper, we firstly propose an innovative bolt‐grouting controlled roof‐cutting for gob‐side entry retaining (BCR‐GER) approach for deep coal mines. Secondly, a mechanical model of “surrounding rock‐supporting body” for BCR‐GER is constructed, which consists of coal wall, roadside props, and gangues in gob (the whole supporting body). Thirdly, the key parameters (ie, cutting height, cutting angle, grouting cable length, and row of roadside props) are designed. Finally, field practice was applied at the No. 31120 haulage roadway of the Suncun coal mine in China, and in situ investigations were conducted for verification. Field measurement results show that maximum convergences of roof‐to‐floor and side‐to‐side were 264 mm and 113 mm, respectively. What is more, the maximum support resistance of roadside props was reduced by approximately 58%. The deformation and failure of surrounding rock were effectively controlled, and the pressure on roadside props was greatly reduced. This research fully considers the bearing properties of gangues in gob, eliminates the secondary disasters caused by borehole blasting, and provides guidance and reference for deep surrounding rock control of the same or similar gob‐side entry.

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“…The maximum subsidence of roof is about 202 mm ( Figure 16). The maximum roof subsidence value is far less than that of caving mining [58] and the maximum allowable security value of 600 mm. The 0622 mining area in Gonggeyingzi Coal Mine was selected as the test mining area.…”

Section: Application Of Granular Backfill Materials In Zhaizhen Coal Minementioning

confidence: 85%

“…Relations between compressive strength and volumetric strain versus curing time of high-watercontent backfill materials are shown in Figure 8, and the values in legend represent different water content. By analysing the figure, induration of high-water-content backfill materials provides early strength, that, within the first 2 h and 8 h account for 21% to 90% of the final strength, thus improving the mining and backfilling efficiency of the panels [57,58]. Furthermore, by analysing the volume of induration of high-water-content backfill materials, the volumetric strain in high-water-content materials changes slightly with time, indicating that the material is incompressible and exerts adequate control over the capacity of overlying strata.…”

Section: High-water-content Backfill Materialsmentioning

confidence: 99%

Properties and Application of Backfill Materials in Coal Mines in China

et al. 2019

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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.

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Upward slicing longwall-roadway cemented backfilling technology for mining an extra-thick coal seam located under aquifers: a case study

Cited by 30 publications

References 41 publications

Influential Factors in Transportation and Mechanical Properties of Aeolian Sand-Based Cemented Filling Material

Influential Factors in Transportation and Mechanical Properties of Aeolian Sand-Based Cemented Filling Material

An innovative approach for gob‐side entry retaining in deep coal mines: A case study

Properties and Application of Backfill Materials in Coal Mines in China

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