The police had been directed there by another officer who had stopped the vehicle several minutes earlier and was ferrying the driver back to the Greymouth police station for a breath test.
The second patrol had been heading to Ngahere to conduct a bail check but was diverted to the coal depot when the first constable said the person they were checking on, was in the vehicle.
Constable Christopher Taylor said that as they came upon the ute it was reversing out of the yard. He processed the driver, Kelly, for drink-driving and tests revealed a breath-alcohol level of 749 micrograms per litre of breath. the legal limit is 400mcg.
Kelly and a witness said they had just been sitting in the car with the motor running to keep warm while they sent texts to friends and family members, seeking a sober driver. The car had not moved at all.
Judge Saunders questioned the wisdom of the police officers leaving the keys in the car.
"Given that there were other drunk young men in the car, the time of night, they are out in the wilderness, no taxis buses or phone booths, you don't have to be a rocket scientist to work out that someone else is going to drive," the judge said.
Police said they would normally have taken the other young men home but Kelly's friends had been "lippy" and abusive.