The Wongawilli system of mining has been in use for over 30 years and has enabled high production rates and acceptable extraction ratios to be achieved in seams less than 4 m in thickness. A modification of the Wongawilli system has been developed to permit the use of a continuous miner and mobile equipment to extract a coal seam 6 m thick._x000D_
Following physical and mathematical model studies the new mining method is now undergoing field trials at Collinsville, Queensland._x000D_
Progress of the field trials to date has achieved 99per centextraction of the upper slice by remote control operation of the continuous miner and established the feasibility of installing resin grouted wooden dowels in the coal floor to reinforce the coal septum. The method is explained in the text._x000D_
Monitoring of the goaf gases as an early indication of spontaneous combustion has been incorporated in the mining cycle by placement of tubes in the goaf as the face retreats and continuous analysis of the goaf gases made at the surface by the National Coal Board tube bundle monitoring system.