WINNING Driving on well-maintained haul roads is key to preserve the condition of equipment and tyres. higher tread wear, stress in tread and plies, weakened bonding and increased heat build-up. Proper inflation ensures maximum ground contact area, optimum sidewall flexibility and reduced heat levels of the tyre. dump pit or load-out area can be a severe tyre hazard and operators should try to avoid making direct contact with it. When backing up to a bumper block or crusher also ensure that no spillage occurs in the pocket. Backing over spilled material or sitting on top of it when dumping a load will place excessive stress on tyres. Windrows are created by normal grader road maintenance can cause sidewall flexing Identifying further hazards Washboard profiles on sections of a haul road create a bouncing motion if the vehicle operator is driving over it at high speed. These conditions affect the sidewalls of the truck's tyres. Too much bouncing may cause tyres to momentarily leave the road surface, amplifying sidewall flexing. Damage from excessive flexing is not immediately noticeable but is cumulative and can be hard to spot in its initial stages. Excessive speed during cornering has a similar effect. Vehicle operators should avoid running over any material that has spilled onto the haul road with the best short-term cause of action is to safely manoeuvre around it until it can be safely removed. The edge of a concrete bumper block at the mine's 18 _ QUARRY SA | MAY/JUNE 2018 The grade of a haul road is important because it affects where the load sits on the tyres.