Jersey Road and Driveway Repairs Limited pleaded guilty to the health and safety infraction in the Royal Court this morning.
The incident, which involved a telehandler forklift, happened at Uplands Farm in St. Peter.
The company admitted it had failed to carry out adequate risk assessments involved in using the forklift, and had failed to identify the risks around the layout of the site for the work that was being done.
It also admitted that it had failed to ensure properly trained workers were operating the forklift.
The company will reappear in the Royal Court on 3 December for sentencing.