Proper sampling of mine gases, analysis and interpretation - a pre-requisite for assessment of sealed off fire area

The incidences of fire in Indian coal mines have a long history of over 140 years and the most important fire affected coalfields include – Jharia Raniganj etc. Major causes of underground fire are considered to be spontaneous heating characteristics of coal. Regular monitoring of underground coalmines, liable to spontaneous heating is useful in terms of safety, reliability, economics and productivity. Monitoring plays an important role for early assessment of fire in underground coal mines and therefore development of different fire indices for devising efficient combat methods. The purpose of this paper is to review the existing successful techniques for sampling, monitoring the mine fire gases and to describe different fire indices such as Graham;s ratio, C/H ratio, J.T. ratio, Morris ratio, RI/RE ratio, Willet’s ratio, etc. for interpretation of status of underground mine fires. A number of fire indices/ratios have been developed so far but none of these are able to quantitatively categorise the status of fire in underground coal mine. The study indicates that the trends of some of the indices taken together should be considered to draw any inference regarding the status of fire