Newstead man Mark Grima, 58, was found guilty of a category two failure to comply with a health and safety duty by magistrate Simon Brown in the Launceston Magistrates Court on April 15, 2024.

Category two breaches are the highest level that can be prosecuted in the magistrates court, and arise from incidents that expose a person to the risk of death, serious injury or illness.

Summing up the events that led up to the incident, Mr Brown said it happened at a Longford construction site where both men were working as subcontractors.

Mr Brown said Grima, a sole trader, had agreed to let the injured man - a plumber who was qualified to use excavators - use one of his machines while Grima was not at the site.

This involved changing the control scheme of the Kobelco excavator from the more common ISO mode - used by Grima - to "backhoe" or SAE mode the plumber was familiar with.

These change how the excavator responds to input through two joysticks found in the control cabin.

Mr Brown said there was no warning or reminder left in the excavator cabin notifying potential operators of the change, and both men left the site that night without changing the controls back.

The next day the plumber was working in a trench near the excavator when Grima started the machine.

Mr Brown did not detail what happened after Grima started the excavator, however a victim impact statement tendered in court said the plumber was left with a broken pelvis.

The plumber said the day of the incident was when "everything changed for me", and he had become "bitter and angry" for a time as his injuries left him unable to get out of bed, let alone work.

The statement continued, with the plumber claiming he had to work "incredibly hard" to regain his physical strength while also dealing with mental trauma.

The magistrate said he found the plumber a more credible witness, as although he had suffered a significant injury there was no trace of ill-will nor attempts to alter details of the incident.

The same could not be said for Grima.

"Your evidence was frankly replete with reconstruction," Mr Brown said.

Mr Brown said Grima had not made it clear he was going to start the excavator, and the plumber could "really only infer" the machine would spring to life.

The magistrate said the excavator's operations manual made the steps Grima should have taken "abundantly clear".

Mr Brown said, even if the control scheme had been reverted to ISO mode, the plumber was within the so-called "crush zone" when Grima started the excavator - an act that adversely affected the man's health and safety.

Grima maintained his innocence.

"I did actually let him know I was going to start the machine," he said.

"I did not deceive anyone.

"It wouldn't have happened if I hadn't been so generous and let him use the machine."

Mr Brown adjourned the matter for sentencing until May 1.