"The section of the platform he was working on did not have adequate guard railing, only a chain barrier which hung low and did not provide adequate fall protection," WorkSafe said.
The man also suffered a bruised hip and concussion.
WorkSafe said Southern Aggregates failed to identify all hazards associated with employees working at height and did not provide adequate guard railing.
"Incidents such as these can be prevented if employers make it a priority to identify all hazards before work starts, as well as ensure that the necessary equipment, appropriate precautions and systems of work are set in place," WorkSafe chief inspector Keith Stewart said.
Southern Aggregates' punishment came the same day a different firm was sentenced and fined for exposing workers to the risk of a fall from height.
Taylor Construction 2011 Ltd was fined $36,750 yesterday in Manukau District Court.The company was penalised after three WorkSafe personnel visited a building site in Botany, east Auckland.
"They found the director/employee of Taylor Construction 2011 Limited, who was also in charge of the work site at the time, walking along the roof trusses," WorkSafe said.
"Inspectors asked him to come down for his own safety but they were ignored."
Inspectors said edge protection and timber platforms used for working at height were inadequate and unsafe.
Meanwhile, a company operating a Dunedin Countdown supermarket where a security gate collapsed on an employee was fined $44,300 and ordered to pay reparations of $33,000.
WorkSafe said the employee suffered compression fractures of several vertebrae, was left in a brace for 12 weeks, and suffered spasms and fractures to the left thumb.
General Distributors Ltd, a wholly owned Progressive Enterprises subsidiary, was sentenced yesterday in Dunedin District Court for failing to take all practicable steps to ensure the safety of its employee.
The employee was closing the security gate at the supermarket on 29 November last year when the gate's op section came loose from its runner, falling towards the employee and pinning him to the ground.