Application of composite fly ash gel to extinguish outcrop coal fires in China

Deng, Jun; Lu, Jun-hui; Wen, Hu; Jin, Yongfei

doi:10.1007/s11069-015-1881-9

Cited by 84 publications

(30 citation statements)

References 13 publications

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“…e spontaneous combustion of residual coal in gob as triggered by air leakage has posed major threats to the safety of miners and mine facilities [1][2][3]. Approximately 56% of mines have been threatened by spontaneous combustion in China's state-owned collieries, which account for 90-94% of Chinese coal mines [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Experimental Study and Application of a Novel Foamed Concrete to Yield Airtight Walls in Coal Mines

Wen

Fan

Zhang

et al. 2018

Advances in Materials Science and Engineering

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Airtight walls are vital to prevent spontaneous combustion of residual coal as caused by air leakage. A new type of foamed concrete (FC) was developed to control air leakage. FC specimens of four densities (250, 450, 650, and 850 kg/m 3 ) were prepared for use in a series of physical and mechanical tests. A thickener was used to control the FC shrinkage and collapse. e permeability of the FC decreased approximately exponentially with an increasing density. On the contrary, the compressive strength (σ) and elastic modulus (E) increased in exponential and linear relationship separately with the increase in density, under uniaxial compression conditions. Under triaxial compression, the compressive strength of the FC increased with an increase in confining pressure and appeared slight plastic. e impact experiment showed that the dynamic compressive strength of the FC appeared to be strain-rate dependent, and it increased with an increase in the strain rate and pressure under a confining pressure. Without a confining pressure, the variation in compressive strength exhibited a slow decrease. Applied FC resulted in a 5 MPa 28-day compressive strength of the airtight wall with no remaining fissures and with air leakage suppression to the gob.

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Section: Introductionmentioning

confidence: 99%

Experimental Study and Application of a Novel Foamed Concrete to Yield Airtight Walls in Coal Mines

Wen

Fan

Zhang

et al. 2018

Advances in Materials Science and Engineering

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“…Chinese workers still use materials like wood, loess, cement grouting [11], and fly ash grouting in coal mines. Recent years have witnessed the development and application of new filling materials, including gel materials, fly ash composite colloid [12,13], paste backfilling [14], thickened mortar [15], rigid polyurethane foam [16], Marithan, and Igloneige [17]. However, all these filling materials have disadvantages.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study and Application of Inorganic Solidified Foam Filling Material for Coal Mines

Wen¹,

Zhang²,

Yu³

et al. 2017

Advances in Materials Science and Engineering

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Spontaneous combustion of residual coal in a gob due to air leakage poses a major risk to mining safety. Building an airtight wall is an effective measure for controlling air leakage. A new type of inorganic solidified foam-filled material was developed and its physical and chemical properties were analyzed experimentally. The compressive strength of this material increased with the amount of sulphoaluminate cement. With an increasing water-cement ratio, the initial setting time was gradually extended while the final setting time firstly shortened and then extended. The change in compressive strength had the opposite tendency. Additionally, as the foam expansion ratio increased, the solidification time tended to decrease but the compressive strength remained approximately constant. With an increase in foam production, the solidification time increased and the compressive strength decreased exponentially. The results can be used to determine the optimal material ratios of inorganic solidified foamfilled material for coal mines, and filling technology for an airtight wall was designed. A field application of the new material demonstrated that it seals crossheadings tightly, leaves no fissures, suppresses air leakage to the gob, and narrows the width of the spontaneous combustion and heat accumulation zone.

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“…After subsurface blasting, the composite gel is injected into the coal seam to extinguish the fire and prevent reignition. The combined method can effectively put out coalfield fire at a reasonable cost [20]. To prevent coalfield fire from occurring in the first place, some scholars have delved into the features of spontaneous combustion of coal.…”

Section: Introductionmentioning

confidence: 99%

Experimental research on temperature variation and crack development in coalfield fire

Fei¹,

wen²

2017

IJHT

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With the destruction of numerous coal seams around the world, coalfield fire is becoming a matter of global concern. This paper probes into the crack features of rock strata in a coalfield fire-stricken area, to answer to call for energy conservation and environmental protection. Specifically, the temperature variation was investigated through simulation experiments based on the coal seam model and rock strata model, and the crack development was qualitatively researched on the surface of coal seam and the overlying strata. The main conclusions are as follows. Comparing the temperature of measuring points on the same horizontal plane, it is concluded that the temperature of the coal seam above the heat source increased with the distance from the heat source within a certain range. The temperature diffusion was rather slow in coal and rock and the fire source movement was very time-consuming. The surface temperature variation of the overlying strata was similar to that of the fire source, indicating that the fire source could be roughly located by the surface temperature variation of the overlying strata. Meanwhile, the thermal destruction resulted from high temperature boosted the crack development in both coal seam and rock strata, and collapse occurred when the coal burned out. During the coalfield fire, the crack development was bolstered by the high temperature produced in the interaction between the crack field and the temperature field; besides, the cracks created a passage for oxygen supply, which favours the coal combustion. All in all, the coalfield fire development was enhanced by the interaction between the crack field and the temperature field.

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Application of composite fly ash gel to extinguish outcrop coal fires in China

Cited by 84 publications

References 13 publications

Experimental Study and Application of a Novel Foamed Concrete to Yield Airtight Walls in Coal Mines

Experimental Study and Application of a Novel Foamed Concrete to Yield Airtight Walls in Coal Mines

Experimental Study and Application of Inorganic Solidified Foam Filling Material for Coal Mines

Experimental research on temperature variation and crack development in coalfield fire

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