GlencoreXstrata has been found not guilty of failing to report a dirty water leak at its Bulga coal mine in 2011.
The Environment Protection Authority says hundreds of litres of dirty water leaked from a faulty pipe at the mine on October 9, 2011.
The water then leaked into a dam and overflowed into the nearby Nine Miles Creek, the Land and Environment Court heard.
The EPA says the tailings slurry flowed about 250 metres along the creek bed.
While GlencoreXstrata plead guilty to polluting the creek, it said the incident was reported within the required timeframe.
Noticing the spill on October 9, a Sunday, workers reported the leak to their seniors who flagged the incident with a pollution hotline on Monday.
The miner said it had spent $287,000 cleaning up the spill, including the use of ‘‘sucker trucks’’ at the creek.
Justice Nicola Pain dismissed the charge saying the EPA had failed to prove the offence beyond reasonable doubt.
The maximum penalty for the offence is a $1million fine plus $120,000 for each day the incident is not reported.
A sentence for the spill itself is still pending.