Model study on dynamics of open fire in underground coal mines under varied air flow

A small scale model representing mine gallery has been designed constructed and installed at Central Mining Research Institute, Dhanbad, India. The basic purpose of the model gallery was to study the complex phenomenon of open fires in simulated underground mine condition. The model is 19 m long having two segments. The first one is 10m long insulated rectangular segment having cross section of 45 cm x 57 cm. Insulation lining of fire bricks leaves space of 13 cm x 13 cm for air flow through the model. The second segment is 9m long 30 m diameter, circular section having a centrifugal exhaust fan installed at its end. Two sets of experiments were carried out in the model at air velocities 1.0 m/s and 1.5 m/s using coal blocks of 5 cm thickness lined in all four inner sides of the model. The coal lining was made for a length of 3 m starting from 1 m of the model entry. After establishing the desired air flow inside the model, fire was initiated artificially at the beginning of the coal zone. Governing parameters such as gas concentration, temperature, pressure drop across fire zone, air velocity and dust concentration inside the model were continuously monitored for about 8 to 9 hours. The paper highlights the salient features of the model, instrumentation system, experimental procedure, important observations, results of the experiment and correlation of findings with particular reference to gas concentration, temperature and fire size

Reversal of underground mine ventilation

Reversal of main ventilation is one of the important means to isolate a fire during emergency. In America, it has been reported that by fan reversal lives have been saved in underground coal mine. Indian coal mines have so far not come forward to adopt this method. Not much research work has so far been carried out in India. This paper deals with international review of the work carried out in other countries. Law relating to reversal of ventilation in different countries of the world is discussed. The effect of reversal on goaf gases and adjustment of ventilating flow is also outlined

Chamber method of ventilation - a proven technology for reducing leakage of air into the goaf

Improvement in climatic conditions at workings in mine having surface cracks by increasing fan capacity is a risky proposition. It may lead to spontaneous heating in the mine due to leakage of air from surface caused by increase in cumulative pressure drop measured from the surface. The above problem cannot be addressed by conventional ventilation system. Anew method of ventilation named "Chamber method of ventilation" have been evolved to ventilate the workings under the situation mentioned above, the method is superimposed on the existing ventilation system of the mine without much modifications or any adverse effect on ventilation of remaining districts. The method was successfully implemented at 1 & 2 incline mines, Jhanjra project, Eastern Coalfields Limited (ECL) to reduce surface air leakage for control of fire in a working longwall panel and for improvement in climatic condition

The austenite -> ferrite transformation in tungsten steels and some other ternary steels

SIGLEAvailable from British Library Document Supply Centre- DSC:D59278 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Fighting mine fires using gases with particular reference to nitrogen

The practice of pumping gases which inhibit combustion for purposes of controlling or extinguishing mine fires is now universally accepted. The practice has been used many times in coal mines in India and the experiences are reviewed. The procedures relating to a membrane based nitrogen generator and to a combustion gases generator are described. The physical properties, practical requirements and economic implications of using different gases is briefly reviewed. Some aspects of the practice as related to mine fires in certain collieries in other countries are dealt with