In his findings yesterday coroner Richard McElrea ruled Tayne had drowned.
The Ministry of Business, Innovation and Employment did not lay any health and safety charges. But Mr McElrea said the accident highlighted the importance of complying with health and safety codes for surface mining.
There was no embankment on site to prevent Mr Bowes' vehicle from leaving the vehicle track, Mr McElrea said.
A perimeter embankment was accepted as industry practice.
"An adequately constructed bund of the type health and safety observed on other mine sites would have probably deflected the vehicle or prevented it from leaving the vehicle track. There is no evidence of excessive speed."
The circumstances highlighted the issue of children being taken on to industrial sites, as well as inadequate lighting.
There was no lighting on site on the evening the accident occurred, Mr McElrea said. "The only lighting at the scene ... [was] the vehicle headlights."
The owner of the mining operation accepted installing spotlights on vehicles would be a worthwhile outcome and "would be reasonably simple" to do.
Four days after the incident, Mr Bowes appeared to have trouble with his memory of the event, and an MRI scan showed he had a malignant intrinsic brain tumour, which has since been treated.
Mr McElrea said this might have contributed to the crash. "It may have affected his ability to work out close distance and space that contributed to the crash."
Mr McElrea called on Worksafe NZ to highlight to the industry the lessons learned from the incident and the need to improve design and policy standards.
Mr Bowes was interviewed by police after the accident but was never charged.
At the inquest, he asked why his daughter had been left trapped in the air pocket for almost two hours.
Mr McElrea said that in his assessment the police actions had been "entirely appropriate".
- additional reporting: Greymouth Star