A friction caused methane ignition occurred at approx. 8:43 pm on the panel 51 MMU 011-0 longwall face. A Horizontal degas hole was encountered between 173 and 174 shield and it was not visible due to the softness of the coal. The head drum was running at roof level and just started to contact the face when the head drum operator saw the ignition. the flame were 18"" high