Review of preventive and constructive measures for coal mine explosions:An Indian perspective

Firedamp and coal dust explosion constitute a lion’s share in mine accidents in a global mining scenario.This paper reports a list of mine explosion disasters since last two decades,a critical review of the different prevention and constructive measures,and its recent development to avoid firedamp and coal dust explosion.Preventive legislation in core coal-producing countries,viz.China,USA,Australia,South Africa,and India related to firedamp and coal dust explosion are critically analysed.Accidents occurred due to explosion after Nationalisation of Coal Mines(1973)in India are listed.Prevention and constructive measures adopted in India are critically analysed with respect to the global mining scenario.Measures like methane credit concept,classification of mines/seams with respect to explosion risk zone,deflagration index;installation of automatic fire warning devices,canopy air curtain technology,explosion-prevention measures,such as fire-retardant materials,inhibitors,extinguishing agent,dust suppressor,and active explosion barrier are discussed in detail to avoid explosion and thereby adhering to zero accident policy due to coal mine explosion.

TGA/DSC study to characterise and classify coal seams conforming to susceptibility towards spontaneous combustion

Thermogravimetric analysis/differential scanning calorimeter(TGA/DSC)technique along with basic coal characteristics study is carried out for eighty coal samples of Indian coalfields,to determine spontaneous combustion propensity behaviour of coal.TGA study of coal samples indicates that there is an increase in the mass of coal samples in the temperature range 150-350℃,which may be due to oxygen adsorption and absorption.The correlation and principal component analysis states that the component of proximate analysis(M_(ad),VM_(d),FR,and VR)have an acceptable correlation with the TGA experiments results i.e.,Tgsh and Tgign.Multiple fixed nonlinear regression analysis shows that thermogravimetry(TG)experiment results Tgign may be the best index to categorise/classify the coal as per their susceptibility towards spontaneous combustion.The authors proposed four groups of classification as per their propensity towards spontaneous combustion depending upon the moisture(M_(ad)),volatile matter(VM_(d)),and TG ignition temperature from differential thermogravimetric(DTG)curve(Tgign)using hierarchal clustering analysis.The coal samples of different seams from Indian coalfield may be classified into four different clusters,viz.very highly/extremely susceptible(Tgign<260℃),highly susceptible(260℃≤Tgign<290℃),moderately susceptible(290℃≤Tgign≤320℃),and poorly susceptible(Tgign>320℃).The field observations and TGA/DSC experiment results with the following statistical analysis substantiate a similar assessment.