Australia.

The Hazelwood Mine is an open cut coal mine, and to maintain the Mine stability while mining is in progress it is required to carry out depressurisation of two major aquifer systems- Morwell formation aquifer system (M1) and Traralgon formation aquifer system(M2). A monitoring of ground water pressures within the Mine and its periphery is carried out to control ground water extraction against stability of the Mine floor and the Mine batters. In the assessment and management of the environmental impacts due to groundwater extraction from these two major aquifer systems regional groundwater monitoring, ground modelling and reporting has been undertaken. In addition land level monitoring is carried out every 5 years to estimate land subsidence due to groundwater extraction. The data is used to calibrate subsidence models for the prediction of land subsidence due to future mining operation. The paper gives insight of aquifer depressurising method used, and the monitoring system adopted to stabilise the mine for coal winning process