Crinum Mine, 15 Longwalls 40 Million Tonnes 45 Roof Falls - What did we Learn?

The Crinum mine is located near Emerald in the Bowen Basin of Queensland and began development in 1994 using 2 Joy 12CM30 continuous miners in the 3.4 m high Lilyvale seam. Longwall production began in 1997 and finished the 15th and final longwall in December 2007. Over the 10 years of longwall production 40 million tonnes have been extracted and the mine has experienced over 40 longwall face, 3 main gateend, and 2 tail gateend roof falls as well as 5 roadway roof falls away from the longwall. Weak roof (less than 10 MPa in the bolted horizon) has been the principal roof control issue at the mine. However, weak, highly cleated coal, water inflow from overlying aquifers, some minor structure and a diatreme in the main headings have also contributed to the challenges at the mine. This paper describes the geotechnical experience over the 10 years, the mine’s approach to addressing the issues and the relative success of these approaches