Sheffield Crown Court heard in December 2014 RMB Contractors Ltd was working on laying a new concrete slab at Ballast Phoenix Ltd, Claywheels Lane, Sheffield.
During ground preparation an old cable duct had to be dug out before the concrete could be laid.
A 21-tonne tracked excavator was being used to dig out the duct, parked behind it was a stationary dumper truck.
As the excavator was working back towards the dumper Richardson was crushed between the two pieces of plant. He was pronounced dead at the scene.
RMB Contractors Ltd of Belper in Derbyshire pleaded guilty to safety breaches and was fined £75,000 and ordered to pay £24,482.80 costs.
Speaking after the hearing, HSE inspector Medani Close said: “Back to back plant activities should be avoided as both pedestrians and vehicles could be put at a higher risk of coming into contact with each other.
“If the two separate work activities cannot be avoided, then the area should be safeguarded and effectively managed with segregation in place, for example using fencing or barriers to delineate the ‘no go’ areas for pedestrians.”