Pike River Coal has been accused of failing to provide the safety features that could have stopped the methane explosion that killed 29 miners two years ago.
The first of two mining safety experts this afternoon gave evidence for the Department of Labour about how Pike River Coal failed to take all practicable steps to ensure the safety of its workers.
One of the experts, Jane Birdsall, told the Greymouth District Court there weren't enough gas detectors and drainage for methane gas in the mine should have been better.
Her points elaborate on those highlighted in the Royal Commission report into the disaster released last year.
The mining company faces nine charges under the Health and Safety Act.
The hearing is expected to finish on Friday.