Development of Fire Resistant Grout Pack Material for Combating Mine Fire

A fire resistant grout pack material having almost zero air permeability and higher compressive strength than cement based material has been developed. It consists of a mix of Magnesium Oxide and Magnesium Chloride in equal proportion with flyash and sand in the ratio of 1:0.33: 1.5. It would be useful for consolidating crushed coal massive for preventing spontaneous heating and also as a cheap fill material for remote sealing to deal with long standing fires

Mine Fire Gas Indices and their Application to Indian Underground coal Mine Fires

Fire gases are liberated due to oxidation of coal in sealed off coal mines. Monitoring of fire gases is the main tool for the determination of fire status. On that basis, different fire indices can be determined for examining the extent of fire and for devising efficient combat methods. In Indian coal mines, mine fires have become a very problematic issue, numbering more than 200, both surface and underground. The most important fire-affected coalfields include Jharia, Raniganj, Talcher, Ib- Valley, Chirimiri, Singrauli and Ramgarh. For surface (O/C) fires different detection approaches are in use. The purpose of this paper is to review the existing successful techniques for monitoring the mine fire gases and describe different fire indices such as CO/O2 deficiency, CO2/O2 deficiency, C/H ratio, Willet's ratio, etc., for interpretation of status of underground (U/G) sealed off fires. Case studies have been presented for assessing status of fire in the U/G mines of some important Indian coalfields

Thermography Technique - A Versatile tool for Assessment and Monitoring of Coal Mine Fire Jharia Coalfield

Globally coal mine fire is a major problem, which endangers not only the valuable lives of miners, but also causes severe environmental pollution and economic losses to coal mining industry. The surface & subsurface features of coal mine fire areas can be detected by different techniques like thermo-compositional analysis supplemented with thermal sureveys. Determinations of temperature by thermometer or thermocouple are sued for its monitoring traditionally but infraed thermograph technique has a greater coverage area, high-efficient and higher precision temperature results. A large surface area can be scanned, presented in thermal & visual form in very short time. This paper depicts the basic principle, monitoring procedure of thermography and its application in Jharia coalfield (JCF) for assessment of coal mines fire and its extent threfore in coal bearing area to prepare its monitoring as well as control strategy. This approach would be usefue to generate data base for ground validation of spatial data acquired by the remote sensing

Role of Chemical additives in retardation of moderate temperature coal fire in Indian coal mines: A new approach on an old problem.

Coal mine fire not only cause huge national economic loss but also creates serious environmental hazard leads to global warming and has a large potential for causing loss of life to the workers involved in mining operations. A huge amount of the prime coking coal reserves of India is locked in the Indian coalfields and it cannot be extracted without extinguishing the existing coal fires. Gradually these fires are spreading perpetually in more areas. Many approaches have been attempted in this direction so that hazard to men and environment as well as economic losses can be minimized. Use of chemical additives to retard spontaneous heating is an important method which can be adopted to prevent or delay the occurrence of spontaneous combustion. In this situation it may sometimes be necessary to use chemical additives for reducing the intensity of fire so that the coal production will not hamper. This paper presents the results of a set of experiments involved the analysis with certain chemicals, individually & in combination in mechanistic prospective and finally best combination was selected

Application of CFD Techniques to Assess Spontaneous Heating/Fire during Extraction of Thick Coal Seam Using Blasting Gallery (BG) Method

Spontaneous combustion is one of the key issues in the blasting gallery (BG) method of coal mining. Earlier most of the BG panels have been sealed due to the occurrences of spontaneous heating during the extraction of the panel. This research paper describes a study on spontaneous heating/fire mechanism in depillaring panels of thick seam mining using laboratory experiments, calculating goaf ignition temperature, field investigation and computational fluid dynamics (CFD) techniques. The laboratory study, i.e. Proximate analysis, ultimate analysis, Sulphur analysis, CPT study, DSC study indicated that coal is prone to spontaneous heating. The CFD simulation study reveals that spontaneous heating of leftover coal in goaf areas alone cannot be responsible for the fire in the BG panel. It indicates that an increase in temperature of the goaf is proportional to the amount of coal left in the goaf region. CFD study for roof fall in leftover coal in the goaf region along with spontaneous heating establishes that temperature rise in goaf is proportional to roof fall area of the panel. The laboratory, field and CFD simulation study clearly verify that spontaneous heating/fire in BG panel is due to the combination of spontaneous heating in leftover coal, and frictional heat generated due to roof fall