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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 Magdalena

Multidisciplinary Aspects of Production Engineering

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2020

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Vol. 3, Iss. 1

206--215

EN

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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Influence of the Permeability of the Longwall Goaf Zones on the Location of an Area With Explosive Methane Concentration Levels

Tutak Magdalena, Palka Dorota

Multidisciplinary Aspects of Production Engineering

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2020

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Vol. 3, Iss. 1

238--247

EN

One of the basic ventilation hazards and, at the same time most dangerous, in hard coal mines is the methane hazard. During the exploitation process using the longwall system with the breaking down of roof rocks, methane is released into mining excavations from both mined coal and the one left in goaves. Significant amounts of methane also flow from the underworked and overworked seams, through cracks and fissures formed in the rock mass. When accumulated at an explosive concentration level in goves and at an appropriate oxygen concentration level and the occurrence of a trigger (e.g. a spark or endogenous fire), methane may either explode or ignite. These are immensely dangerous phenomena. Therefore, the possibility of their occurrence should be limited. The article presents the results of the research aimed at determining the impact of the permeability of goaf zones on the distribution of methane and oxygen concentration levels in these goaves. The study was carried out for the longwall ventilated with the Y system. The model analysis was conducted, the results of which allowed the authors to determine these distributions. On their basis, both the location and size of the areas in which hazardous methane concentrations could occur were designated. The results are of great practical importance as they indicate areas in goaves where preventive measures should be implemented.

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Monitoring and controlling methane hazard in excavations in hard coal mines

Szlązak N., Obracaj D., Borowski M., Swolkień J., Korzec M.

AGH Journal of Mining and Geoengineering

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2013

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Vol. 37, no. 1

105--116

EN

At present Polish mining regulations require the use of methane monitors with short or fast response times for current switchboard types when methane hazards co-exist with rock-burst hazards. According to regulations the number and location of sensing devices for methane monitors should be consistent with the conditions present in any given monitored area. This article presents an analysis of regulations referring to a control system and methane hazard monitoring. The analysis takes the Polish legislative system into consideration and looks at regulations in selected countries with well-developed mining industries. Methods for methane hazard control in blind headings with auxiliary ventilation and in mining areas are also discussed. Methods are illustrated by using examples of monitoring methane hazard control in driven roadways and in longwalls ventilated by U and Y systems.

PL

Aktualnie obowiązujące przepisy górnicze nakładają obowiązek stosowania metanometrii automatycznej o skróconym czasie repetycji pomiarów lub o pomiarze ciągłym dla nowo budowanych central oraz w przypadkach, gdy zagrożenie metanowe występuje w układzie skojarzonym z zagrożeniem tąpaniami. W przepisach określono warunki dotyczące liczby i miejsc zabudowy czujników metanu. W artykule przedstawiono analizę przepisów decydujących o systemie kontroli i monitoringu zagrożenia metanowego. W analizie uwzględniono stan prawny obowiązujący w Polsce oraz wybranych krajach z rozwiniętym przemysłem górniczym. Omówiono metody kontroli zagrożenia metanowego w wyrobiskach przewietrzanych lutniociągami oraz w rejonach eksploatacyjnych. Metody te poparte zostały przykładami monitoringu i zwalczania zagrożenia metanowego w drążonych wyrobiskach korytarzowych oraz w wyrobiskach ścianowych przewietrzanych systemami U i Y.