NOTE: The push cat operator should be extremely
cautious in NOT hitting the rear scraper tires with the
The push cat operator must ensure that the
reinforced section of the dozer blade is centered on the
scraper rear push block. Additionally, the push cat
operator must be alert to turns made by the scraper that
might cause the push cat to apply unequal pushing force.
This could result in the dozer blade contacting the
scraper rear tires or causing the scraper to jackknife.
The push cat should continue pushing after the scraper
has a full load to give the scraper a boost in leaving the
After the scraper is fully loaded and has reached the
haul road, the operator should raise the bowl to travel
height and proceed to the fill or dump area in the highest
gear range practicable. The bowl travel height should
be no higher than needed to clear any obstacles on the
haul road. A low bowl height allows better control of
the scraper by keeping the center of gravity low and
preventing the loss of time needed to lower the bowl, as
the scraper approaches the fill area. The best bowl
height is the height at which the bowl must be in when
the load is spread.
When hauling down steep grades, lower the bowl
until the blade drags to slow the scraper down. When
traveling over a slippery haul road, keep the cutting
edges as close to the road as possible to allow for a fast
emergency stop by dropping the bowl.
When traveling over haul roads, avoid holes and
large obstacles that may damage the scraper tires. When
making sharp turns, allow enough clearance for the
length and width of the scraper to keep the scraper
wheels on the road.
Spreading or Unloading
When approaching the fill area, lower or raise the
scraper bowl to the depth of fill desired. The speed of
the scraper must also be adjusted for this depth, such as
a high speed for a thin spread or a slower speed for a
To start spreading, raise the apron by engaging the
apron control lever to allow the material to fall out of
the bowl. The size of the apron opening depends mainly
upon the depth of the spread and type of material being
spread; for example, a thin layer of free-flowing sand
needs a fairly small apron opening and a high travel
speed, while a thin spread of wet clay will need a larger
opening and a slower travel speed.
After the apron opening has been adjusted and the
dirt flowing through the opening lessens, engage the
ejector lever to finish unloading the scraper bowl. When
the scraper is empty, engage the ejector lever to return
the ejector to the rear of the bowl and lower the apron.
Unloading techniques are as follows:
. Keep the scraper moving while unloading.
Stopping when unloading on soft fill costs production
time by needless shifting and the possible miring down
of the scraper.
l Always make an even spread, so the next trip will
not be rough.
. If possible, when traveling out of a fill, pass back
over the area you have just filled to compact it with the
large scraper tires.
Returning to the Cut
After the scraper is unloaded and has reached the
haul road, return to the cut as soon as possible. When
returning to the cut, carry the scraper bowl high enough
to avoid any haul road obstacles, yet low enough for safe
handling of the scraper. Carrying the bowl low allows
for quick lowering of the bowl to stop the scraper in the
event of an emergency. Allow plenty of room for the
rear wheel of the scraper to avoid obstacles when
making tight turns, and maintain a safe speed for the
condition of the haul road.
WORKING DIFFICULT MATERIALS
Special operating techniques are required when
performing scraper operations in difficult materials,
such as wet or sticky material, loose sand or gravel, and
Wet and Sticky Materials
When unloading wet and sticky material, do not try
to spread the material too thin. Always keep the bowl
high enough to allow the material to flow back under the
scraper. Open the apron wide enough to allow an easy
flow out of the bowl, Bring the ejector forward with
short, snappy movements of the ejector control lever to
shake the material loose from it. Allow a little time
between each ejector movement to avoid compacting
the material between the apron and ejector. In some
cases, shifting the ejector between forward and reverse