Komatsu PC138USLC Operation & Maintenance Manual page 224

OPERATION
MACHINE OPERATIONS AND CONTROLS
Loading Work
In places where the swing angle is narrow, work efficiency can be
enhanced by locating the dump truck in a place easily visible to the
operator.
Loading dump trucks is easier and the loading capacity is greater
if the hydraulic excavator loads from the rear of the dump truck
rather than from the side.
Refill and Finishing Work
(Only machines with blade specification)
When refilling after excavation and when smoothing the ground
surface, use the blade.
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