Method and apparatus for deslagging a gasifier's combustion chamber which has accumulated a residual solidified slag as a result of the fuel being combusted. The gasifier is provided with means for liquefying the slag into a flowable state by heating the combustion chamber to a temperature of which the slag will flow. To epitomize the gasifiers' deslagging mode, the combustion chamber is provided with an array of strain monitoring or measuring load cells which are located to detect and collectively respond to movement at the combustion chamber floor whereby to control the slag removing procedure.