West Coast mining company Copper Mines of Tasmania has been fined ,000 in the Hobart Magistrates Court for discharging mine tailings on to Crown land outside its mining lease.
The tailings entered an unnamed creek.
The offence occurred on 18 September 2004 when 2800 cubic metres of tailings and water escaped from a ruptured pipeline after the mine experienced a power failure and re-started operations.
Magistrate Helen Wood said that although the impact was contained to a relatively small area of land, there was potential for material environmental harm to have occurred and that the company had not followed standard procedures when re-starting the operation.
The Director of Environmental Management, Warren Jones, said that tailings spillages could cause significant environmental damage, especially if the tailings entered waterways.
"Mining companies must ensure that tailings pipelines are regularly inspected and properly maintained," he said.
"Contingency plans must be in place to deal with any leaks before environmental harm can occur."
The company was found guilty of two offences under the Environmental Management and Pollution Control Act 1994.
An application for technical costs was made and will be determined on a date to be fixed.