Powercoal Pty Ltd operates eight underground coal mines in New South Wales. The company produces approximately eleven million tonnes of coal per annum for both the domestic thennal and export markets. Approximately 40% of Powercoal ' s production is from continuous miners, either from first workings or secondary extraction. Much of this coal is won from the Wallarah, Great Northern and Fassifern Seams of the Newcastle Coal Measures where either local geology and/or subsidence constraints preclude the use of longwall methods. PIior to place change mining (PCM), typical "whole of panel" productivity averaged 350 tonnes per seven hour shift or 7.3 l:onnes per face man hour.( Note: This measure is calculated using hours at the face and face manning numbers employed im the process.) In 1989, faced with increasing competition in the domestic thermal mal.ket, the PCM system was identified as a means to deliver competitive productivity within the geological and mining constraints commonly encountered at Powercoal's Lake Macquarie mines. The system was successfully introduced in 1992 at Myuna Colliery in the Fassifem Seam. Productivity increased to 800 tonnes per seven hour shift (12.1 tonnes per face manl hour) with peaks of up to 1500 tonnes per seven hour shift (22.7 tonnes per face man hour). The system relied on a coal clearance system of three Joy 15SC shuttle cars of 9.5 tonnes capacity each. The system was introduced at Cooranbong Colliery in 1994 and modified to suit local geology and mining constraints. Coal clearance typically utilised two Joy 15SC shuttle cars. As ir[lprovements to the system were made, average productivity in first workings increased during 1995/96 but has plateaued at 800 tonnes per eight hour shift (12.7 tonnes per face man hour). Peak performances of up to 2000 tonnes per eight hour shift (28.6 tonnes per face man hour) have been achieved.