TRENCHING COMPANY SOLVES ROCKY PROBLEM - KPI-JCI

TRENCHING COMPANY
SOLVES ROCKY PROBLEM
Case Study #402
This Texas-based trenching and excavating company uses a portable screening plant
to transform excess backfill from its trenching operations into processed and
sized material for select fill and base material.
As one of the world’s largest custom trenching and mass-rock excavating companies in the world, H.L. Chapman Pipeline, Inc. is known
to be a problem solver. While working on the US 183A toll-road project in central Texas, the company needed a way to turn excess
trenching material into a useable product. Their innovative solution came in the form of a track-mounted, mobile screening plant from
KPI-JCI: the FT6203 shown in the above photos. H.L. Chapman’s screening crew would move the unit to a berm of rock that had been
trenched with a rock miner—and then use a backhoe to load the raw material into the screening plant. The unit automatically screened
and stockpiled the rock into three different sizes.
H.L. Chapman Pipeline, Inc. is a
company most contractors have
heard of at one time or another. It is
one of the largest custom-trenching
and rock-excavating companies in the
world—and it has a long history of
tackling major challenges. H.L.
Chapman maintains headquarters in
Austin, Texas, and has offices in San
Antonio, Texas and Las Vegas, Nevada.
They conduct their excavating
operations in 28 states.
Considering the geographical
scope of the company’s business, it
may seem unusual that the company’s
business focus is so narrow: H.L.
Chapman works solely on trench and
excavation, with most of its work being
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The key to the equipment’s on-job success is its ability to
move forward alongside the trenching action, thereby
eliminating the need to transport the material. It is a
surprisingly simple but very effective operation.
done in rocky terrains. Within this
target area, the company has devoted
its efforts to learning how to trench
and remove rock faster than almost
anyone else, without the use of
explosives.
With this background, H.L.
Chapman frequently looks at problems
from many angles to find new
approaches. One of their most recent
challenges resulted in a decision that
was quite unusual, even for a company
with 25 years of experience.
The “problem” in this case had to
do with excess trenching waste,
machine backfill, and milled material
from a highway project in the Texas Hill
Country. The project involved
construction of a new toll road— US
Highway 183A—which was designed to
relieve traffic in the central Texas
counties of Travis and Williamson. The
new highway is being built parallel to
existing US 183. The 11.6-mile (18.7-
km) highway is expected to be
complete this spring.
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The challenge in this case resulted
in an unusual—and profitable—solution.
While raw trenching backfill is often
problematic, it is possible to screen it
to create products for use in area
construction.
For Chapman, the key was a
FT6203 mobile screening plant from
KPI-JCI. The FT6203 is one of the
world’s largest mobile processing
plants that was designed specifically
for recycling and aggregate
production, as well as for multiple siteprep
applications. Despite the mobility
of its track mounting, it can output
commercial and spec base, sized
course, intermediate and fine
materials requiring single-stage
reduction. Its heavy track drive
provides excellent onsite mobility. For
longer moves, it is transportable on a
low-boy trailer. H.L. Chapman
considered it to be a perfect match for
the project. The FT6203 “crawls”
alongside the trenches where rockcutting
machines are at work. It
screens the material to make two and
even three products, as needed, for
road base and other materials.
According to Allen Summers, H.L.
Chapman equipment superintendent,
the key to the equipment’s on-job
success is its ability to move forward
alongside the trenching action, thereby
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eliminating the need to transport the
material. It is a surprisingly simple but
very effective operation.
“As the material comes out of the
trencher or road miner, we scrape it
up and build a big berm pile,”
Summers explained. “Then we set up
the screener on a pad right next to the
berm pile. We use a back-hoe to take
the material off the berm and put it
into the FT6203.”
On the highway project, the
products made included 1 in. (2.5 cm)
minus, 1.75 to 2.75 in. (4.5 to 7.0
cm), and over 2.75 in. (7.0 cm). With
the screening plant’s built-in delivery
capability, the products are easily
sorted into separate piles for future
use.
H.L. Chapman generally uses the
FT6203 in an open circuit in conjunction
with the trenching machines
or road miners that are doing
excavation or ditch work. Of course,
the idea of using a screening plant for
this application was not entirely new.
H.L. Chapman had rented another type
of screening plant first, but when the
company saw the KPI-JCI plant in
operation, they sent back the other
plant and purchased the FT6203.
The production results have been
impressive according to Charles
Farmer, the screen operator with H.L.
Chapman. “Our productivity varies
according to the material,” he said.
“There are different things that affect
it: the dampness of the material, or
what kind of material we’re screening,
or if we are screening a dirt substance
rather than a rock substance. It can
be hard to specify ahead of time what
it will really get a day. If it is solid rock,
we can probably get 1,000 yards (914
m3)—or about 1,300 tons (1,180
tonnes)—a day through it. If it is bigger
material, of course, that’s going to
change it. It varies.”
One advantage of the FT6203 is
the flexibility of the plant’s output.
Farmer noted that the company
generates materials for a variety of
uses, including a pad base for
commercial construction. “That is
basically a select fill,” he explained. “You
can’t really call it road-quality base
because there is no clay mixed in with it.”
Farmer said that the screening
plant’s operations have been mostly
smooth and trouble-free during its
approximately one year of use.
“We didn’t have many problems out
of it in that time—just regular, routine
maintenance. It did the job for me, and
it was a big job. I think we ran
somewhere near 500,000 yards
(382,000 m3) through it in that time
period, working on the US 183A tollroad
project. Then we ran another
50,000 yards (38,200 m3) through it
at another project in the south part of
Austin, Texas.”
Summers agreed. He said there
were some minor problems in the first
six months, but the factory support
was excellent. “The people at the KPI-
JCI factory bent over backwards to
help us,” he said. “The service
representative is the most helpful
person I have ever seen in this industry.
He helps us in a heartbeat!”