Taharoa Ironsands Limited has been fined $60,750 for discharging 4,000 litres of diesel into the Wainui Stream in August last year.
The case was brought against the West Coast mining company following a number of complaints regarding contamination in the Wainui stream at their mine site near Kāwhia.
Waikato Regional Council opened a formal investigation into the matter and found that diesel discharge had occurred in a high-voltage area where access was controlled. Through a number of events, diesel had flowed from a fuel bladder into the site’s stormwater system and then into the stream.
Te Kuiti District Court judge Melanie Harland referred to the company's offending as a ‘careless’ act.
The judge noted that the lack of clear communication, failure to follow isolation procedures and restricted access to the high-voltage area had all contributed to the breach.
The council's investigations and incident response manager, Patrick Lynch, says, "This was completely avoidable. Companies that use and store hazardous substances have to ensure they have good infrastructure and procedures in place.
"Accidents can happen. When they do, substances like fuels and oils need to be contained so they do not escape into the environment and cause harm."
