In the present work, the rates of decomposition for Siderite and Magnesite minerals found in lignite ashes have been evaluated by isothermal thermogravimetry by monitoring the weight loss for 60 min at 350°C, 400 "C, 500 °C and 575°C and the mineralogical composition of coal ash was evaluated .The comparative account is also given for DTA of coal/mineral mixtures in air atmospheres which show the major exothermic effects in the initial and final temperature zones of major peak configurations. 


A G M VASANDANI ,M I BHANGER ,G M KUMBHAR ,S W SHAH ,