Darren Mundell had been standing on the machine to cut overhanging tree branches when he fell off.
Dumfries Sheriff Court heard that on 7th November 2016, Kendal-based M&W Tarmacadam Contractors Ltd was working at the Arkleton Estate in Langholm, Dumfriesshire.
With overhanging trees presenting an obstruction, Darren Mundell clambered on to the bonnet to cut branches. When he fell into the tar hopper he sustained a fractured back and damaged spinal cord, causing permanent paralysis from the waist down.
An investigation by the Health & Safety Executive found that M&W Tarmacadam Contractors had failed to plan the task of cutting the overhanging branches.
The company was fined £10,000 after pleading guilty to breaching Regulation 4 of the Work at Height Regulations 2005.
HSE Inspector Kirstin Lynchahon said after the hearing: “M&W’s failings resulted in serious and life changing injuries which could have easily been prevented had the company planned the work at height. Planning the branch cutting activity would have included an assessment of the risks and either avoidance of working at height using long reach tools or measures being put in place to prevent a fall. Work at height is the biggest single cause of fatal and serious injury in the construction industry, particularly on small projects.”