He was facing the rare and serious charge of manslaughter, which he had earlier pleaded not guilty to, but crown prosecutor Ross Douch today told Justice Timothy Brewer that charge would be withdrawn at sentencing.
Bishop instead pleaded guilty to the lesser charge of being a director of Steelcon and employer, that it failed to take all practicable steps that its employee, Michael Haines, was not exposed to the hazard of a trench collapse while at work.
Bishop, and his company, will now both be sentenced on their respective charges in February.
The court heard Mr Haines had worked for Steelcon as a construction labourer since June 2011.
In May 2014 Steelcon was undertaking a contract in Te Poi, Matamata relating to effluent management systems.
Part of the work was the installation of a new 3.6m diameter concrete effluent transfer tank and piping connecting the new tank to an existing part of the effluent system.
A 4sq m deep hole was dug to accommodate the new concrete tank.
Part of the requirements under the Act mean that employers need to ensure all excavations of a minimum 1.5m depth should be shored by installing panels to prevent collapse.
The trench had not been shored and despite that, Bishop had allowed staff entry to the site to allow areas of the concrete tank to be spray painted.
On May 27, Bishop and Mr Haines began work on digging the trench in which an outlet pipe would ultimately be laid.
Bishop was on the excavator -- which had a 600mm wide bucket attached -- and he began digging in a straight line away from the tank towards the existing effluent installation.
About that time, Mr Haines got into the trench and began moving some dirt away.
Then suddenly, five cubic metres -- or about eight tonnes -- of soil collapsed, burying Mr Haines.
After his death, the site was inspected and it was discovered the fill from the trench appeared to mostly be silt.
"The make up of the fill showed it had been placed in layers but not in an engineered manner. Such non-engineered fill tends to vary in terms of composition. Silts consequently need to be treated with caution ... as silts are typically problematical as they typically have low residual strengths and once excavated they lose cohesion. Soft to firm silt typically performs poorly in unsupported excavations and ... very susceptible to collapse, with little or no warning, particularly if moist."
The area had been the subject of heavy rain in the preceding days.
When interviewed by police, Bishop said he noticed that part of the excavation was starting to crack and yelled out to Haines that he shouldn't be in there.
He said it appeared Haines was endeavouring to dig some dirt away, using a long-handled shovel.
He said the pipe was to have been laid mechanically using the excavator so there was no need to go into the trench and that he'd talked to Mr Haines about that plan.
Bishop accepted that anything over 1.5m deep should be shored but in this case no one was meant to be in the trench so he did not shore it.
When asked if there had been times when staff had gone into trenches more than 1.5m deep, Bishop admitted that from time to time people "do things" but did not wish to expand further.
It was also revealed that it wasn't Bishop's first time not shoring up excavation sites.
Earlier in the month, when Bishop was working on another site a foreman from another construction company approached him and suggested that the excavation should be shored for safety reasons.
Bishop replied that his "safety record was good".
