Complete Demolition had been contracted to demolish a school at Stanney Lane, Ellesmere Port in Cheshire to make way for a new leisure centre.
On 27 November 2013, while the site was being cleared, a skip truck driver reversed into a space that a 40 tonne excavator was vacating.
Another worker, who was on foot, was standing in the same area. As the excavator manoeuvred it hit him, knocked him to the ground and ran over his foot.
The Health and Safety Executive (HSE) found there was insufficient control of workers and that the procedures to separate pedestrians and vehicles on the site were inadequate.
Liverpool Crown Court heard that the victim has undergone several operations to rebuild his foot and is still unable to work.
Complete Demolition pleaded guilty to breaching Section 2(1) of the Health and Safety at Work Act and Regulation 13(2) of the Construction (Design and Management) Regulations 2007, which covers the safe management and monitoring of construction work by contractors. It was fined and must also pay costs of £7,247.
Speaking after the hearing HSE inspector Deborah Walker said: "The company failed to properly plan for the duration of the works, putting pedestrians at risk."