Caterpillar’s new “D” series 789 haul truck replaces the previous C model and incorporates new performance, productivity, safety and serviceability features into this latest version in the 25-year-old 789 line. Payload is 181 metric tons (200 short tons), a 2.5% increase from the C model. The mechanical-drive truck’s standard engine is a Cat 3516C EUI quad turbocharged diesel providing 1,566 kW (2,100 hp) gross power, 10% more than the previous model. According to Cat, the 3516C standard engine is capable at altitudes up to 3,658 m (12,000 ft) with no derate. Cat’s 3516B diesel also is available for mines requiring an engine with gross power of 1,417 kW (1,900 hp) to match with existing fleets.

Cat now offers its Combination body for the 789D—a multi-purpose, high-volume body designed to reduce haulage costs of well-fragmented, low-density material—as well as an updated dual slope body along with its X and MSD II bodies. The D version also has been designed to accommodate larger tires in the 40.00-R57 and 42/90R57 sizes; standard tire size is 37.00-R57. The new model retains Cat’s oil-cooled braking system, which combines the service, secondary, parking brake and retarding functions in the same system for optimum braking efficiency.

Standard, deluxe and deluxe cold weather cab options are available. Diagonal stairways and an optional powered ground-level stairway provide access and egress. The 789D is equipped with the Object Detection system as standard equipment. The system uses radars and cameras to give the operator audible and visual alerts of detected objects. The 789D also is available in an XQ configuration to comply with requirements for reduced external sound levels.

Daily service points are located for easy access, with most at ground level. Isolation and lockout systems also are conveniently located. A maintenance platform provides access to the engine, steering hydraulic tank and battery compartment. Tie-off points are provided for work above ground level. An optional fast fill service center enables high-speed fueling and oil exchange, and optional quick-change rims are available to simplify tire replacement.  

Several features extend reliability and durability. A new pump drive system provides continuous rear axle filtration. Extended life disc brakes are now standard equipment and may achieve up to double the wear life of the previously used brake material. The brakes are resistant to glazing and deliver consistent braking power and reduced maintenance. New air intake and filters have a new seal, which provides easier servicing and lower maintenance costs.