A Study on Preventing Spontaneous Combustion of Residual Coal in a Coal Mine Goaf

Wang, Yongjun; Zhang, Xiaoming; Sugai, Yuichi; Sasaki, Kyuro

doi:10.1155/2015/712349

Cited by 15 publications

(19 citation statements)

References 14 publications

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“…Szlązak, in turn, stated that this value fell between 0.015 and 0.0015 m/s [50]. Wang et al [51] specified that this value ranges from 0.001 to 0.02 m/s.…”

Section: Coal Spontaneous Combustion Hazard In Goafs-preventionmentioning

confidence: 99%

The Method of Combating Coal Spontaneous Combustion Hazard in Goafs—A Case Study

et al. 2020

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One of the major natural hazards occurring during the process of mining exploitation are endogenous fires. They cause very large material losses and constitute a threat to the health and life of the workers. Such fires usually start and develop in the goafs. The remaining coal and the oxygen-containing air flowing at a certain rate may lead to endogenous fires. The basic element of the assessment of the occurrence of an endogenous fire and the degree of its development is the chemical composition of the air flowing out of the longwall and the goafs. The monitoring of this composition also makes it possible to assess the severity of such a fire. The damage that can be caused by the endogenous fire requires scientific and experimental research being carried out on a wide scale in order to limit its occurrence and development. All papers and research mentioned in the paper aim to find a tool that will help to control the fires. The paper discusses the development of a new and original method of combating the threat of endogenous fires. It is based on the installation designed to feed an ash and water mixture or an ash and water mixture with carbon dioxide to goafs. The foundation of the paper is a method based on a vast depth of expertise and knowledge gained by the authors in the field of combating endogenous fires. The developed installation prepares and transports ash and water mixtures together with carbon dioxide to the zones with high probability of endogenous fires. The mixture is a preparation of the surface of a mine, and later, it is transported underground by pipelines to the goafs where a high level of the fire hazard was identified. The construction of the system and the composition of the mixture used are both original solutions; their practical application limited the process of spontaneous heating of coal. Monitoring the chemical composition of gases in the air of the goafs made it possible to control the effects of applied measures; it proved that carbon dioxide used as an inert gas disturbs the process of carbon oxidation, and the water and ash mixture limits the inflow of the air with oxygen. The advantage of the method is particularly evident in the case of the exploitation of deposits where coal has a short incubation time. This original approach allows for a better and more effective response to endogenous fires.

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“…Szlązak, in turn, stated that this value fell between 0.015 and 0.0015 m/s [50]. Wang et al [51] specified that this value ranges from 0.001 to 0.02 m/s.…”

Section: Coal Spontaneous Combustion Hazard In Goafs-preventionmentioning

confidence: 99%

The Method of Combating Coal Spontaneous Combustion Hazard in Goafs—A Case Study

et al. 2020

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“…in goaves. These fires arise from the oxidation of coal, leading to its self-ignition Brodny and Tutak, 2016b;Li et al, 2008;Tutak and Brodny, 2017b;Tutak and Brodny, 2018;Wang et al, 2015;Yuan and Smith, 2008;Yuan and Smith, 2009). In total, 63 endogenous fires were reported in Polish hard coal mines between 2009-2018, of which 29 were located in the area of longwalls.…”

Section: Introductionmentioning

confidence: 99%

Influence of the Volumetric Expenditure of Air Supplied to the Longwall Through the “Y” Ventilation System on the Location of an Area at the Risk of an Endogenic Fire

Tutak

2020

Multidisciplinary Aspects of Production Engineering

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In the case of longwall ventilation, in the underground hard coal mines, a phenomenon related to the migration of a certain amount of the air stream supplied to the longwall deep into goaf zones occurs. One of the wall ventilation systems, in which this phenomenon is quite intense, is the so called “Y” ventilation system. This migration is immensely unfavorable because it can lead to the self-heating process of coal left in a goaf and, consequently, to an endogenous fire. Such a fire is a great threat to both the safety and continuity of operation processes. For this reason, various activities are undertaken to prevent such a fire from occurring in goaf zones. One solution is a method presented in this article. It aims at determining an area in goaf zones, where an endogenous fire may occur. The study focused on the longwall ventilated with the Y system. This area was determined based on two criteria, namely air velocity and oxygen content. The study was carried out for various volumes of air supplied to the longwall. Therefore, the purpose of the study was to develop research methodology and determine the location of an area at the risk of an endogenous fire. The location of this area was determined for three different volume expenditures of air supplied to the longwall ventilated with the Y system.

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“…This speed depends on the type of roof rocks forming the caving (since they influence their sealing degree) as well as on the volumetric flow rate of the air supplied to the longwall. However, the issue of how the volumetric flow rate of the air supplied to the longwall impacts the risk of endogenous fires has been discussed in several publications [21][22][23][24].…”

Section: Introductionmentioning

confidence: 99%

“…Chumak et al [22], on the other hand, assumed that the critical speed value ranges from 0.015 to 0.0017 m/s, whereas Szlązak reported that this value is between 0.015 and 0.0015 m/s [23]. On the other hand, Wang et al [24] indicated that this value ranges from 0.001 to 0.02 m/s. The speed ranges indicated are quite extensive.…”

Section: Introductionmentioning

confidence: 99%

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The Impact of the Strength of Roof Rocks on the Extent of the Zone with a High Risk of Spontaneous Coal Combustion for Fully Powered Longwalls Ventilated with the Y-Type System—A Case Study

Tutak

Brodny

2019

Applied Sciences

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During the ventilation of longwalls in hard coal mines, part of the air stream migrates to the goaves with caving. These goaves constitute a space (void) filled with rocks following coal extraction. In the case where these goaves contain coal susceptible to spontaneous combustion, the flow of such an air stream through the goaves may lead to the formation of favourable conditions for coal oxidation, self-heating and spontaneous combustion. Such an area is referred to as the zone with a particularly high risk of spontaneous coal combustion (endogenous fires). The location and extent of this zone depend on many factors, with one of the most important being the permeability of the goaves which determines the tensile strength of the roof rocks forming the caving. This strength determines the propensity of these rocks to transform into the state of caving and the degree of tightness of the cave-in rubble (treated as a porous medium). The purpose of the present paper is to determine how the tensile strength of roof rocks influences the extent of the zone with a particularly high risk of spontaneous coal combustion (endogenous fires) in caving goaves of the longwalls ventilated with the Y-type system. To achieve this goal, model-based tests were conducted for a region of the longwall mined with caving and ventilated with the Y-type system. Critical air speed and oxygen concentration values in the caving goaves of this longwall were determined for the actual conditions of exploitation. These parameters define the risk zone of spontaneous coal combustion. The tests also helped to determine the extent of this zone, depending on the strength of the rocks forming the caving. The results obtained unequivocally indicate that the type of rocks forming the caving affects its permeability and the extent of the risk zone for spontaneous coal combustion. At the same time, the distribution of this zone is substantially different than in the case of other ventilation systems. The results obtained are of real practical significance for preventive measures to reduce fire risks. The effectiveness of these measures significantly improves the safety of mining exploitation.

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A Study on Preventing Spontaneous Combustion of Residual Coal in a Coal Mine Goaf

Cited by 15 publications

References 14 publications

The Method of Combating Coal Spontaneous Combustion Hazard in Goafs—A Case Study

The Method of Combating Coal Spontaneous Combustion Hazard in Goafs—A Case Study

Influence of the Volumetric Expenditure of Air Supplied to the Longwall Through the “Y” Ventilation System on the Location of an Area at the Risk of an Endogenic Fire

The Impact of the Strength of Roof Rocks on the Extent of the Zone with a High Risk of Spontaneous Coal Combustion for Fully Powered Longwalls Ventilated with the Y-Type System—A Case Study

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