The sensor used in French mines to detect firedamp (methane) in airways is a platinum filament catalytic sensor. Its perfonnance characteristics have been constantly improved by new conditioning techniques : heating filaments functionning at high temperature, signal processing. In this document, we describe the operadon of the sensor and the conditioning techniques successively used in different mine gas detectors, stressing for each the improved performance obtained. In conclusion, we will show that the last technique recendy developed broadens the field of use of the sensor to industrial and domestic explosimetry.