2) peak performance practices - wire rope
TRANSCRIPT
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1999 - 2004 Harnischfeger Corporation. All rights reserved. All materials contained herein are protected by the United
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prior permission of Harnischfeger Corporation. You may not alter or remove any trademark, copyright or other notice
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Section Page1 - Introduction. . . . . . . . . . . . . . . 1
2 - The Basics: Wire Rope
Components, Construction
and Classifications . . . . . . . . . . 3
3 - Characteristics of
Mining Rope . . . . . . . . . . . . . . 11
4 - Inspecting Wire Rope,
Sheaves and Drums . . . . . . . . 15
5 - Receiving and Handling
Wire Rope . . . . . . . . . . . . . . . . 21
6 - Structural StrandBoom Pendants . . . . . . . . . . . . 25
7 - Recommended Practices for
Extending Wire Rope Life . . . 27
Glossary . . . . . . . . . . . . . . . . . . . . 31
Index . . . . . . . . . . . . . . . . . . . . . . 33
CONTENTSWIRE ROPE
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Wire rope is used in a variety of ways to pull, lift or
support one or more objects, or to transmit forces or
energy from one place to another. It is an essential
component in a wide range of applications, from
elevators and ski lifts to cable cars, broadcast trans-
mission towers, cranes and conveyor systems, as
well as in mining shovels and draglines.Understanding the principles that govern wire rope
performance in surface mining equipment is indis-
pensable to achieving peak performance practices
and avoiding the cost of premature wire rope
replacements.
This document is designed to provide basic infor-
mation about the design and construction of wire
rope, and its proper care and use on shovels and
draglines.
It is intended to help mine management, mainte-
nance personnel and equipment operators maximize
the life and performance of wire rope.
For further information on training, wire rope selec-
tion and after-sale support, please contact your
P&H MinePro Services representative.
Page 1
1 - Introduction
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ComponentsStandard wire rope is a flexible line made of wires
twisted or braided together to provide tensile
strength. Wire rope consists of three basic compo-
nents: a central core that serves as the ropes foun-
dation and support system; individual wires; and
multi-wire strands wrapped around the central
core (Figure 1). These components can be com-
bined in literally hundreds of arrangements, yield-
ing different characteristics for different applica-
tions.
Cores As the foundation of a wire rope, the core
must be able to support the normal bending andcompressive loads imposed on the ropes strands.
Wire rope cores may consist of a fiber core (FC),
an independent wire rope core (IWRC), or a wire
strand core (WSC).
A fiber core may be made of natural fibers such as
manila or sisal, or of synthetic filaments, such as
polypropylene or glass fibers. An independent
wire rope core or a wire strand core is most often
made of steel. Fiber core ropes offer considerably
more bendability than steel but they are seldom
used in todays surface mining equipment.
Wires The individual wires in a wire rope maybe of uniform diameters but are more often a com-
bination of different diameter sizes arranged in
specific geometric patterns. By a wide margin,
most of the wire used in wire rope today is manu-
factured from high carbon steel, although other
materials are also used, including iron, stainless
steel and bronze.
Strands Wire rope strands may be laid in any ofa wide variety of geometric patterns. Strands form
the basis of wire rope construction and classifica-tion covered later in this section.
Page 3
CORE
WIRE
CENTER
WIRE
STRAND
WIRE ROPE
2 - The Basics:Wire Rope Components,Construction andClassifications
Figure 1 Wire rope is made from three basic com-
ponents: the core, individual wires and strands.
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PEAK PERFORMANCE PRACTICES WIRE ROPE
Page 4
Grades and FinishesAs the most common material used in wire rope
manufacture, high carbon steel is available in sev-
eral grades, as designated by the plow steel
strength curve. This curve originated in England
long ago to differentiate the quality of steel used
in the manufacture of plows, and it has been used
ever since.
In increasing levels of performance, the most
common grades are: mild plow steel (MP);
improved plow (IP); extra improved plow (EIP or
XIP); and extra extra improved plow (EEIP or
XXIP).
For comparison purposes, extra extra improved
plow (EEIP) provides approximately 10% greater
nominal strength than extra improved plow (EIP),
and about 25% more than improved plow (IP). It
should be noted that in applications involving high
cycle bending, higher wire strength does not nec-
essarily mean longer fatigue life.
The most common finish for steel wire is bright
or uncoated. Steel wire may also be galvanized, or
zinc coated, to protect against corro-
sion. Drawn galvanized wire offersthe same strength as bright wire, but
wire which is galvanized at finished
size provides approximately 10%
less strength. Although most wire
rope is uncoated, both internal and
external lubrication are essential to
allow wire rope to bend and flex.
Construction:Types of LayIn addition to its component parts,
wire rope is identified by its con-
struction. The differences can be
seen in the ways in which the wires
are laid to form strands, and in the
way the strands are laid about the
ropes core.
All types of lay are similar in that all wires are
wound to form a helix, or spiral, around the
strands central wire, as are the strands around theropes core. However, the types of lay differ in
that they can be laid in regular or lang config-
urations.
Note that the wires in regular lay ropes appear to
line up parallel to the axis of the rope, as shown in
Figure 2 A and B. In lang lay ropes, the wires
appear to form an angle with the ropes axis,
Figure 2 C and D. Distinct manufacturing
techniques are used to produce these differences.
In addition, regular lay and lang lay ropes can be
wound to the right, similar to the threading in a
right hand bolt (Figure 2 A and C) or to the
left (Figure 2 B and D). Thus, the various
types of lay are: Right Regular Lay (RRL), Left
Regular Lay (LRL), Right Lang Lay (RLL) and
Left Lang Lay (LLL).
Right regular lay is used in the widest range of
applications. Right lang lay and, to a lesser extent,
left lang lay ropes are used in many equipment
applications. Left lang lay ropes are typically used
Figure 2 A comparison of typical wire rope lays: A. Right Regular
Lay; B. Left Regular Lay; C. Right Lang Lay; D. Left Lang Lay.
A
B
C
D
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2 - The Basics: Wire Rope Components, Construction and Classification
in special applications such as plain-faced or
smooth drums. Users often alternate between left
lay and right lay to minimize wear to the drum.
Advantages of lang lay Regular lay is morestable and more resistant to crushing than lang lay.
Regular lay is also more common, especially in
smaller diameter ropes, but lang lay offers certain
advantages, including superior fatigue resistance
and abrasion resistance. There are a few provi-
sions worth noting, however.
For example, in Figure 3 note how the axis of the
wire relates to the axis of the rope in regular layand lang lay strands. When regular lay rope is
bent, as when passing over a drum or sheave, the
same amount of bend is imposed on the crowns of
the outer wires. This increases the pressure and
wear on the rope.
The worn crown combined with the shorter
exposed length allows the wire to spring away
from the rope axis, resulting in reduced fatigue
resistance.
Another reason for lang lays superior fatigueresistance is that its outer wires provide about
30% more exposed area than regular lay.
Comparing the valley-to-valley distances of the
individual wires in the two examples in Figure 4,
the regular ropes distance is 7/8 in. (22.2 mm)
versus 1-1/8 in. (28.6 mm) for the lang lay.
Because the individual strand wires are less in line
with the axis of the rope, there is less axial bend-
ing of the outer wires, and greater torsional flex-
ure. Overall, lang lay exhibits 15 to 20% superior-
ity over regular lay when bending. Lang lay is
used in applications where it is subject to repeated
bending and the ends are fixed.
Page 5
Figure 3 Lang lay construction provides a greater wear area than regular lay, increasing its fatigue resistance.
WEAR AREAWEAR
AREA
SUPPORTING
INNER WIRE
LANGREGULAR
a
b
a
b
Figure 4 The wear patterns in regular lay (above
left) and lang lay (above right) are distinct.
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PEAK PERFORMANCE PRACTICES WIRE ROPE
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Critical disadvantages of lang lay Langlay rope has two critical limitations. First, if
either end of the rope is not fixed, it will rotateseverely when subjected to a load. Second, it does
not withstand the crushing forces against a drum
or sheave as well as regular lay. Therefore, lang
lay rope must always be properly secured at both
ends, and it should never be used over small diam-
eter drums or sheaves under extreme loads. It also
follows that lang lay does not respond well to
inferior drum winding conditions.
Lay as a unit of measureIn addition to helping define a ropes construction,
rope lay is also used as a unit of measure. One
rope lay is the length of one complete spiral of a
strand about the ropes core.
Measuring a ropes lay length is an important part
of rope inspection and is covered in Section 4.
Preformed vs. non-preformed wire
Preforming wire, i.e., forming individual wiresand strands to the helix shape during manufactur-
ing, makes the wires and strands lay at rest in
the rope. Preforming wire also improves fatigue
resistance. Wire rope used in mining shovels and
draglines is preformed. Non-preformed wire will
broom when cut, unless the end is first secured
with wire seizing (Figure 5).
Figure 5 To prevent strands and individual wires from unraveling or brooming, seizing is applied to
wire rope before cutting.
Single Layer Filler Wire
Figure 6 Some of the common classifications of wire rope are
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2 - The Basics: Wire Rope Components, Construction and Classification
Wire Rope ClassificationsWire ropes are classified according to three basiccriteria: the number of strands in the rope; the
number and arrangement or pattern of wires in
each strand; and a word or letters to describe the
geometric arrangement of the strands. Some
arrangements are filler wire (FW), Seale (S) and
Warrington (W).
Single Layer: the most basic rope pattern, con-sisting of uniform-diameter wires wrapped around
a single center wire of the same diameter. The
example shown (Figure 6) is a 7-wire strand.
Filler Wire (FW): two layers of same-sizedwires wrapped around a center wire in which the
inner layer has half as many wires as the outer
layer. Small filler wires equal in number to the
inner layer wires help position and support the
two layers.
Seale (S): two layers of wires, equal in number,around a center wire. The large outer wires rest in
the valleys of the inner layer of wires.
Warrington (W): two layers of same-sizedwires in the inner layer, and two alternating diam-
eter sizes in the outer layer. The larger outer wires
rest in the valleys of the inner wires, and the
smaller outer wires rest on the crowns of the inner
layer of wires.
Combined Patterns, e.g., Warrington
Seale (WS): two or more of the above patternscombined in a single operation. In the example
above, an inner layer of Warrington is combined
with an outer layer of Seale. Another type of com-
bined pattern is Seale Warrington Seale (SWS).
Multiple Operation, or 2-Op: strandsrequiring two separate manufacturing operations
in which one of the above patterns is covered with
an outer layer of uniform-diameter wires. The sec-
ond operation is required to provide the outer
layer a different direction or length of lay to meet
particular performance requirements.
Construction vs. ClassificationIn addition to its class, a wire rope is also identi-
fied by its construction. For example, a 6x7 rope
designates a rope with six strands with each strand
having seven wires. Other designations include
6x19, 6x37, 6x61, 7x19, 7x37, 8x7, 8x19, 19x7,
etc.
However, these are nominal designations which
may or may not reflect the ropes actual construc-
tion. Each designation includes multiple types of
construction. The 6x19 class, for example,
includes 6-strand ropes with 16 through 26 wires
per strand; the 6x37 class includes 6-strand con-
structions with 27 through 49 wires per strand.
Page 7
Seale Warrington Warrington Seale Multiple Operation
ve. Each classification is based on the geometric arrangement of wires and strands.
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PEAK PERFORMANCE PRACTICES WIRE ROPE
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To avoid confusion, it is best to order wire rope by
its actual construction, not just its classification. A
full description of a wire ropes construction typi-
cally includes the following:
length
diameter
preformed or non-preformed
direction and type of lay
finish
grade
type of core.
Certain assumptions may be made if one or more
of these specifications is omitted. If the direction
and type of lay are omitted, it is assumed to be
right regular lay (RRL). If the finish is not shown,
it is assumed to be uncoated or bright. For
example:
500 ft 3/4" 6x21 FW pref RLL IP IWRC
The above description defines a 500 foot length of
rope, 3/4 inch (19 mm) in diameter, with six
strands, 21 wires per strand, filler wire, pre-
formed, right lang lay, improved plow steel, and
an independent wire rope core.
Most wire ropes used for drum applications on
shovel and dragline applications are constructed of
six, seven or eight strands.
6x25FW
6x26WS
6x41WS
6x49SWS
6x55/6x61SWS
Compacted6Strand
Compacted8Strand
Compacted6Strand
PlasticImpregnated
Compacted8Strand
PlasticImpregnated
8x19
8x37
GalvanizedBoom
SupportStrand
Draglines
Boom Hoist Line
Drag Line
Hoist Line
Boom Pendants
Shovels
Boom Hoist
Crowd & Retract
Hoist Rope
Trip Rope
Boom Pendants
Wire Rope Selection Guide
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2 - The Basics: Wire Rope Components, Construction and Classification
Why Wire Rope Must Be Freeto MoveWire rope is often referred to as a complex
machine made of many moving parts, and for
good reason. A rope of 6x37 construction has
approximately 222 wires: six strands, each with
37 wires, plus the core. Note that the actual count
may vary by specification and manufacturer. All
these components must be able to slide and move,
both individually and in concert with adjacent
strands and wires. To understand why and how a
ropes wires and strands move, consider what hap-
pens as a 1 in. (25.4 mm) rope passes over a 30 in.
(762 mm) sheave.
As shown in Figure 7, the rope is subjected simul-
taneously to the opposing forces of tension and
compression. As a result, the inside length of the
rope retracts while the outside length expands.
Using the mathematical formula for a circles cir-
cumference (where C is the circumference and D
is diameter) the outside of the bend is about 3-1/8
in. (79.4 mm) longer than the inside bend (Figure
8). Note that we divide the circumference by 2
because the rope is in contact with only half the
circumference of the sheave.
Page 9
30"
1"
32"
TENSION
COMPRESSION
p = 3.14 C = p x D2
Outside circumference =
3.14 x 32 = 100.48 = 50.24 (1276.1 mm)2
Inside Circumference =
3.14 x 30 = 94.20 = 47.10 (1196.3 mm)2
Difference =
50.24 - 47.10 = 3.14 or about 3-1/8 (79.4 mm)
Figure 8 The difference between the inside and outside bends of the wire rope is about 3-1/8 in.(79.4 mm).
Figure 7A wire rope passing over a sheave or
drum is subjected simultaneously to the opposing
forces of tension and compression.
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PEAK PERFORMANCE PRACTICES WIRE ROPE
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To allow the rope to adjust to this kind of bend-
ing and flexing, the clearances between its compo-
nents are precision engineered to tolerances mea-sured in 10,000ths of an inch (0.0025 mm). This
kind of metal-on-metal sliding contact also helps
explain why proper lubrication is essential to wire
rope performance.
The D/d RatioThe relative sizes of a sheaves diameter, D, and
a ropes diameter, d, is one of the factors that
determines the ropes fatigue resistance and ser-
vice life.
In the previous example, the sheaves diameter is
30 in. (762 mm) and the rope's diameter is 1 in.
(25.4 mm), producing a D/d ratio of 30 to 1. As
the D/d ratio decreases, the bend is drawn tighter
and tighter, increasing the tension on the rope,
reducing its fatigue resistance, and causing the
rope to wear prematurely.
Fatigue life of drum ropes is a function of both
bending stress over the drum and pulsating axial
stress from the loading. Using larger ropes than
specified will hurt bending stress but help axial
stress. Slightly larger ropes have been applied suc-
cessfully when within the limitations of the
groove size and spacing.
It is important to remember that, for any given
rope diameter, changing to a smaller sheave diam-
eter reduces its service life when bending is the
determining factor. Conversely, using the same
rope on a larger sheave increases its service life
(Figure 9). Larger diameter sheaves also have
higher rotational inertias and thus could accelerate
external wire wear and breakage such as a fairlead
application where sheave overspinning is a factor.
100
90
80
70
60
50
40
30
20
10
0
RELATIVE
ROPES
ERVICEL
IFE
0 10 20 30 40 50 60
D/d RATIO
Figure 9 A rope working with
a D/d ratio of 26 has a relative
service life of 17. If the samerope is used on a sheave that
increases the D/d ratio to 35,
the ropes relative service life
increases from 17 to 32, a gain
of 88 percent.
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With so many varieties of wire rope available,
sorting out the specifics required for a particular
application can be a challenge. Of the characteris-
tics listed in this section, two of the most impor-
tant for shovel and dragline operations are abra-
sion resistance and fatigue resistance (Figure 10).
Abrasion ResistanceA ropes abrasion resistance is its ability to with-
stand wear and metal loss due to sliding contact
with other materials, including metal sheaves and
rollers, drums, and rock. The chief causes of metal
loss are rope running through sheaves that are too
small, an improper fleet angle, and pulling a
drag rope through the roll at the edge of a pit.
Generally speaking, larger diameter wires
offer greater abrasion resistance because
they have more surface to wear away than
smaller wires.
In addition to its metal being worn away,
wire rope can be distorted or peened.
Peening occurs when the ropes exterior
surface is flattened by striking against a
hard object.
Metal loss and peening often occur simulta-neously. Metal loss reduces a ropes strength
and can cause individual wires to break. The
distortion caused by peening limits the normal
sliding action and adjustment of wires during
normal operation, resulting in reduced fatigue
life. Peening also causes the metal in the wire
to harden, making the wires more brittle and
less flexible.
Fatigue ResistanceA ropes fatigue resistance is its ability to endure
repeated bending over a period of time. The ropes
key points of vulnerability are where it passes
over sheaves and drums, points of restriction suchas the ropes end attachments, and areas subject to
load changes.
The greatest load changes occur at the ropes pick-
up points, the parts in contact with the sheaves
Page 11
3 - Characteristicsof Mining Rope
Figure 10 Wire rope is a complex machine made of many
moving parts which are subject to abrasion and fatigue.
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PEAK PERFORMANCE PRACTICES WIRE ROPE
Page 12
6
9
10
10
12
12
14
16
18
6x7
6x19 S
6x21 FW
6x26 WS
6x25 FW
6x31 WS
6x36 WS
6x41 SFW
6x46 SFWNUMBEROFOUTSIDEWIRESPERST
RAND
LEAST
RESISTANCETO
ABR
ASION
GREAT
EST
LEAS
TRESISTANCETOBENDING
FATIGUE
GREATEST
Figure 11 The X Chart demonstrates the inverse relationship between abrasion resistance
and bending fatigue resistance. As abrasion resistance increases, fatigue resistance decreases,
and vice versa.
and drums when the initial shock load of each lift
is applied.
Vibration on ropes is often of a bending nature,
and the stress is maximized where the vibration is
dampened, i.e. at the pick-up and termination
points. This bending causes rubbing between the
inner and outer strands. When vibratory bending
failures occur, it is very common for the wire
breaks to be in the inner wires.
Vibration sends energy in the form of shock waves
through the rope and that energy must be absorbed
at some point. Wherever the waves are dampened
is where the energys impact will be concentrated,
including the end attachments and the tangent
where the rope contacts the sheave or drum, i.e.
the pick-up points.
As a rule, the greater the number of outside wires
in a strand, the greater its fatigue resistance will
be. This is due to the fact that smaller wires have
a greater ability to bend, and more wires usually
means smaller wires.
From the above, it should be clear that as a ropes
abrasion resistance increases its fatigue resistance
decreases, and vice versa. Since most applications
require a balance of these characteristics, the
industry has developed a rope selection aid called
the X Chart (Figure 11).
High Performance Wire RopeTo help offset the inverse relationship between
abrasion resistance and fatigue resistance, andprovide the best of both attributes, most manufac-
turers offer high performance ropes.
Compacted Strand One type of high perfor-mance rope is compacted strand. Each strand is
drawn through a die to compact and create a
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3 - Characteristics of Mining Rope
smooth flat surface all around the strands (Figure
12) prior to laying them around the core. This
process increases the metallic surface of the ropeand provides a flattened outer wire surface,
enhancing breaking strength, fatigue resistance,
abrasion resistance and crushing resistance.
Virtually all ropes used on shovels are compacted,
as are some dragline ropes.
Figure 12 Compacting the outer strands of a wire
rope increases its surface area, improving resis-
tance to bending fatigue, abrasion and crushing.
Swaging is another compacting technique in
which hammers are used to compact the strands,
resulting in a very dense cross section. Die form-
ing is a more controlled process than swaging and
results in greater product uniformity.
Plastic-Filled IWRC Rope and Plastic-
Coated Rope Plastic-filled wire rope is ropewhose internal spaces are filled with a matrix of
plastic. Plastic filling improves bending, abrasion
and fatigue life by reducing internal contact
between wires and strands, thus reducing internal
and external wear. The plastic filling helps support
and separate the ropes outer strands. It keeps the
lubrication from escaping, helps keep foreign
material out, can help prevent corrosion, and
makes the rope cleaner to handle.
Various constructions of wire rope are available
with a plastic coating which may be applied to the
ropes exterior or just the gap between the IWRC
and outer strands.
Plastic filled or coated wire rope helps keep the
grooving in sheaves and drums polished and in
good condition. It prevents corrugation because
there is full contact with the groove.
Strength
A third consideration in selecting wire rope for
shovels and draglines is its strength. In addition to
the plow steel strength curve, several other mea-
sures of strength are applied to wire rope.
Nominal strength refers to the manufacturerspublished catalog strength. This figure is calculat-
ed according to standard industry procedures.
Since a ropes strength decreases with use over
time, nominal strength applies only to new,unused rope.
Minimum acceptance strength is rated 2-1/2% below the nominal strength to allow for vari-
ables that might affect a ropes breaking strength
during testing. A minimum acceptance strength
for a nominal breaking strength of 100,000
pounds would require an actual breaking load by
test to destruction of at least 97,500 pounds.
Breaking strength measures the amount oftensile load required to pull apart a piece of rope.
It is important to distinguish between dynamic
and static breaking strength, however. Most mini-
mum breaking strengths listed in catalogs are
obtained under quasi-static or slow loading speed
test conditions, but most rope failures happen as a
result of dynamic loads, i.e. when the rope is
moving rapidly.
Page 13
FLATTENEDSTRAND
SWAGED
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PEAK PERFORMANCE PRACTICES WIRE ROPE
Page 14
Reserve strength is the combined strength ofall the wires in a rope except those in the outside
layer of the strands.
Crushing ResistanceA fourth consideration for shovels and draglines is
a wire ropes crushing resistance, i.e., its ability to
maintain its round shape when one layer of rope is
spooled on top of another. In shovel and dragline
applications, only the boom hoist ropes may be
spooled in this way; all others are spooled in a
single layer.
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Regular inspection is an essential part of any wire
rope peak performance program. Catching a prob-
lem in its early stages of development allows you
to adjust operating practices and prevent potential-
ly dangerous breaks while the rope is under load.
Inspecting a rope, especially for the first time,
begins with good preparation, as outlined in the
steps below.
1. Gather your inspection tools and sup-
plies. For a complete inspection of the rope,sheaves, drums and end attachments, youll need
(Figure 13):
an inspection log
a caliper
a tape measure
sheave and drum groove gauges
chalk
cleaning cloths
carbon paper and clean white paper
a pen and pencil
leather gloves
2. Identify the rope. Before you can know
what to look for in your inspection, you have to
know something about the rope. Begin by identi-
fying its diameter and construction. Note that all
measurements of a ropes diameter must be per-
formed at the widest point, as shown in Figure 14.
2a. Measure the rope diameter. To get anaccurate dimension, measure three times at the
same location. On a six-strand rope, for example,
youll measure all three diameters, i.e. the dis-
tance between the outsides of strands 1 and 4, 2
and 5, and 3 and 6, as shown in Figure 14. On an
eight-strand rope you may want to measure allfour diameters.
Page 15
4 - InspectingWire Rope, Sheavesand Drums
Figure 13 The essential tools for inspection
of ropes, sheaves, drums and attachments.
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Repeat these measurements at several locations on
the rope, especially at the pick-up points, in areas
of heavy wear, and in areas close to the end
attachments. Record them in the inspection log.
2b. Compare your measurements with
the ropes catalog or nominal diameter.Keep in mind that all manufacturers make their
ropes with diameters larger than their nominal list-
ings. This is to allow for the initial pull down of
the diameter when new, unused rope is placed
under load for the first time and the wires seat
in.
Note that there is no industry standard for the dif-ference between nominal and manufactured diam-
eter sizes. For specifics, check with the individual
manufacturer.
A change in diameter can be a warning sign of
potential or actual failure, so it must be measured
during every inspection. A new ropes initial mea-
surement should be taken after it has had a chance
to seat in. The initial measurement is then used as
a reference for future comparisons.
A gradual decrease in diameter is to be expected
over time, but a sudden decrease, especially a
large one, may be a sign of a broken core.
2c. Identify the ropes construction. Thisis done by making a physical count of the ropes
strands and wires per strand. The rope manufac-
turers test certificate should simplify the task.
Just be sure the rope matches what is on the cer-
tificate.
Note that manufacturers do not always supply test
certificates, and those who do usually do so only
by special request.
3. Verify the ropes breaking strength.Again, this can be done by checking the manufac-
turers test certification. Remember, there is a dif-
ference between static breaking strength and
dynamic breaking strength and, in most cases, the
test certification will be based on a quasi-static
test. If youre not sure, check with your supplier.
4. Review the retirement criteria and
verify the design factor. The design factor is
a ratio of a ropes nominal or catalog strength tothe rated load of the application intended.
Multiplying this rated load by the design factor
provides the minimum catalog strength of the rope
required for the application.
Rated Load x Design Factor = Minimum Catalog
Strength
Most ropes designed for surface mining applica-
tions employ a design factor of 5.0. Using this
design factor, a rated load for the application of 80
tons (81.3 tonnes), requires a rope with a mini-mum catalog strength of 400 tons (406 tonnes),
calculated as 80 x 5 (81.3 x 5). Always consult the
manufacturer when a rope of a different catalog
strength is intended to be used.
5. Review the ropes inspection history.
This can be a big time and money saver, but only
if the records are accurate and up to date. The
inspection history can provide valuable clues as to
Page 16
PEAK PERFORMANCE PRACTICES WIRE ROPE
Figure 14 The correct way to measure a ropes diameter is across the widest point, from crown to crown
of opposite strands, not from valley to valley.
ACTUAL
DIAMETER
INCORRECTCORRECT
16
5
4 3
2
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4 - Inspecting Wire Rope, Sheaves and Drums
Page 17
the cause and remedy of rope problems. If the
inspection log indicates rope removal due to local-
ized damage in a particular area, inspect that areafirst.
Inspection MethodsThere are many different methods and procedures
used to inspect wire rope used on mining equip-
ment. These can and do vary from mine to mine,
the type of equipment at the mine, the functional
application of the wire rope and the specific safety
standards and requirements enacted at the particu-
lar mine site. Thus the responsibility for definingand implementing inspection procedures rests
with the management of each individual mine, the
specifics of which cannot be addressed here.
Rope Retirement CriteriaUsing a rope beyond its useful life is a dangerous
practice that can put peoples lives in jeopardy.
Any cost savings gained by delaying rope replace-
ment can be lost quickly if the rope breaks during
operation and causes bodily injury or damage tothe machine.
Always replace wire rope according to the equip-
ment manufacturers or wire rope manufacturers
specifications for the application. Follow the spec-
ifications for length, diameter, class of construc-
tion, breaking force, and type of rope attachments
or terminations. Maintaining 2-1/2 to 3 wraps of
rope on the drum for all authorized working con-
ditions determines the shortest length.
Note: Physical dimensions of the outer geome-try of rope attachments can vary from one man-ufacturer to another. Do not order ropes withattachments from suppliers other than the origi-nal equipment manufacturer without first verify-ing it will fit into the physical opening and permit
the normal range of movement after installation.
No precise rules can be given for determination of
the exact time for replacement of wire rope and
strand since many variable factors are involved.
Some variables include:
number of hours in service
type of application (how the rope is used)
the loads applied to it, and their frequency
frequency of lubrication, or no lubrication
effect of corrosive environment
A shorter working life of rope and strand will
result from lack of maintenance. The remaining
strength and safety of a wire rope or strand in con-
tinued use is determined by both careful inspec-
tion for signs of deterioration, and the judgement
of an authorized, qualified person.
Note: Discard criteria will vary based on theapplication; for example, hoist ropes versus
drag ropes.
Use the following basic criteria when evaluating
the condition (strength and safety) of wire rope
and strand. If any doubt exists about the remaining
useful life of a wire rope or strand it should be
removed from service!
Running Rope Retirement Criteria
Six randomly distributed broken wires in onelay length, or three broken wires in one
strand in one lay. Six wires broken at the
drag rope socket (in this case, the rope could
be shortened and re-socketed).
ONE ROPE LAY
Figure 15 The length of one rope lay is the distance
required for a single wire to make one complete helical
convolution about the ropes core.
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Page 18
PEAK PERFORMANCE PRACTICES WIRE ROPE
Probable Cause
Overload or localized wear. If overload is sudden, it
will cause a square-off break.
Overloading, kinking, damage or localized wear weak-
ening one or more strands.
Lack of proper lubrication. Exposure to salt or alka-
line water. Idle periods.
Shock loading.
Rolling the reel over an obstruction or dropping from
the truck onto any hard surface results in rope
distortion or damage. Use of chains for lashing or use
of a lever against the rope.
Result of improper handling, installation or operating
abuse.
Kinks or bends in rope due to improper handling dur-
ing installation or service. Repetitive contact point
causing severe localized wear.
Excessive fleet angle or lack of attention when rope is
installed. Worn grooves, worn flanges, lack of a level
wind system.
Damage due to scraping of rope over sharp surface
or because of improperly fitted clamps or clips.
Ropes operated over damaged sheaves or drums or
improperly aligned equipment. Drum groove too deep
for fleet angle of rope.
Severe bending. Possibly due to excessive vibration,
or due to poor operating conditions.
Allowing rope to drag or rub over any small radius
bend.
Overloading or poor spooling.
Problem
Rope broken square-off
One or more strands broken
Undue corrosion
Protruding rope core
Ropes damaged in transit to
location
Ropes show kinks, dog legs,
or other types of distortion
Ropes show excessive wear
in spots
Ropes damaged by irregular
or improper winding on drums
Unequal pressure and
distortion of wires and rope
Side wear on rope
Fatigue breaks in wire
Spiraling or curling
Ropes show excessive
flattening or crushing
Wire Rope Inspection Checklist
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4 - Inspecting Wire Rope, Sheaves and Drums
Note: The number of wire breaks that cannotbe accepted varies with rope usage and con-
struction. For general applications, this six-and-three criteria is satisfactory. Common practiceby mine operators for draglines is to use this
criteria for hoist ropes only.
One outer wire broken at the contact point
with the core of the rope which has worked
its way out of the rope structure and pro-
trudes or loops out from the rope structure.
Wear of one-third the original diameter of
outside individual wires from abrasion.
Kinking, crushing, cutting, birdcaging,
unstranding or any other damage resulting in
distortion of the rope structure.
Evidence of any heat damage from any cause
including an electric arc.
Protruding core (from an opening between
strands).
Valley breaks - when two or more wire frac-
tures are found.
Severe corrosion particularly in the vicinity
of end attachments. Reductions from nominal rope diameter of
more than 10% of a new rope after installa-
tion, or an observable increase in rope lay
length.
Rope Pendant Retirement Criteria
More than two broken wires in one lay in
sections beyond end connections or more
than one broken wire at an end connection.
Loose or damaged strands.
Standing Rope Retirement Criteria
More than two broken wires in one lay in
sections beyond end connections or more
than one broken wire at an end connection.
Loose or damaged strands
Note: Where possible, ropes should be rotat-
ed out of sheave contact areas for inspection.
Strand Pendant Retirement Criteria
Visible or sounding breaks in 25% of the
outer wires or 10% of the total, whichever isless; or 10% loss of strength based on size
and load capacity of each broken wire.
Significant rust staining at the socket termi-
nation, indicating internal corrosion and pos-
sible wire breaks.
Significant reduction in diameter at the sock-
et, indicating internal core breakage.
Excess catenary, indicating internal wire
breaks and loss of load carrying ability.
Inspecting Sheaves andDrumsUse the appropriately sized groove gauges to
check sheaves for wear, keeping in mind that
gauges designed for field use are based on differ-
Page 19
A
CB
Figure 16A sheave groove gauge should make 150
contact with the groove, as in Example A. Example B
is too tight, and example C is too loose.
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PEAK PERFORMANCE PRACTICES WIRE ROPE
ent groove dimensions than those used by manu-
facturers for new components.
Field gauges are made to the ropes nominal or
catalog diameter plus a minimum acceptable frac-
tional oversize value based on the ropes diameter
and construction.
This allows the gauges to be used to establish the
minimum condition for worn grooves (Figure 16).
When the gauge perfectly fits the groove, the
groove is at the minimum allowable contour. Any
narrower fit means the groove is not recommend-
ed for further use.
In addition to the groove contour, a full inspectionincludes the grooves depth, width and smooth-
ness. Corrugations or imprinting caused by the
ropes texture (Figure 17) can seriously damage
the rope and is cause for replacing the sheave.
Corrugation is more likely with bright rope than
with plastic coated rope; plastic-coated rope may
even help smooth the groove.
Also examine sheaves for damaged or chipped
flanges, cracks in the hubs or spokes, out-of-
roundness, waviness, alignment with other
sheaves, and for wear or damage to bearings andshafts.
The main functional drums on shovels and
draglines use grooved barrels with a single layer
of rope. For drum inspections, check the drums
general operating characteristics. Adequate tension
must be maintained on the rope so that it winds
properly. Be sure the rope follows the groove and
that the wraps are tight and consistent. If any
looseness or irregular winding is observed, check
the rope for kinks. Pay particular attention for any
scuffing as it leaves the drum groove.
Measure the grooves for proper contour, as in the
sheave inspection procedure above. Also check
that adjacent grooves have enough clearance
between them that one wrap of rope does not
scrub the next wrap. Drums that become corrugat-
ed need to be corrected or replaced.
Page 20
Figure 17A corrugated sheave can cause seri-
ous damage to a wire rope.
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Receiving and handling of wire rope calls for spe-
cial caution. Improper unloading, unreeling, wind-
ing, and storage can cause permanent damage,
making a rope useless even before its been put
into service.
Upon receipt of a shipment, the rope should be
carefully inspected to see that it matches the ship-
ments paper work, including description tags,
purchase orders, invoices, etc.
Unreeling and WindingBefore a rope is unreeled, the reel must be mount-
ed on a shaft supported by jacks or a roller payoff
so the reel can turn. As the rope is unreeled, ten-
sion must be maintained on the rope with a brak-
ing device or similar mechanism to avoid slack in
the rope which can lead to kinking.
If rope is to be transferred from one reel to anoth-
er, or from a reel to a drum, care must be taken to
avoid causing a reverse bend in the rope. Areverse bend is induced when unreeling from the
top of the pay-off reel to the bottom of the take-up
reel, or vice versa. This will cause the rope to
rotate more under load and, more importantly, it
will cause uneven loading of the strands and
wires, thus greatly reducing its life.
The correct way to transfer the rope is from the
top of one reel to the top of the other, or from bot-
tom to bottom (Figure 18).
Page 21
5 - Receiving andHandling Wire Rope
Figure 18 Transferring a wire rope from the top of one reel to the bottom of another reel or drum can create a
reverse bend. The correct method is to make such transfers from top to top or bottom to bottom.
CORRECT
REEL
REEL
REEL
REEL
DRUM
DRUM
DRUM
DRUM
INCORRECT
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When working with shorter cut length
coils of rope, the coil should be wound
and unwound by standing it androlling it like a tire. It should never be
laid flat and the free end pulled out.
Laying the coil flat makes it extremely
susceptible to kinking and reverse
bends (Figure 19).
Storing Wire Rope
Wire rope should be stored under a
roof and/or covered by a tarp. If this is
not possible, liberally coat the outerlayers with lubricant. Keep rope away
from heated air and moisture.
Reels should be stored and moved in an upright
(on edge) position and not on the painted side.
Used rope should be lubricated, if possible, and
stored on reels the same as new.
End Preparations and
TerminationsRopes are normally shipped with their ends seized
to prevent the strands and wires from unraveling.
In some applications, seized ropes can be installed
with no further preparation required.
Where tight openings or tight bend radii are
involved with drums or sockets, however, special
end preparations, or beckets, may be required. For
example, beckets are used when another rope or
tugger line is used to pull the new rope into
place. Four basic types of preparations are shownin Figure 20.
Wire rope should never be shortened, lengthened
or terminated with the use of a knot. A single knot
in a wire rope can reduce its strength by 50 percent.
Ferrule Becket Hoist RopesMost of the wire rope consumed on excavators is
used as drum ropes (hoist, drag, etc.) and most
drum ropes on shovels (95%) use ferrule becketfittings for end preparations. Adhere to the follow-
ing principles when working with ferrule beckets.
1. Pull-off strength The ferrule should beswaged onto the rope so as to develop at least 30-
35% of the rope's breaking strength. Any less and
the ferrule can pull off. Pull-off strength is a func-
tion of swaging force and ferrule length.
Page 22
PEAK PERFORMANCE PRACTICES WIRE ROPE
Figure 19 A coil of rope should never be laid flat
and uncoiled. Uncoiling in this way can easily
create kinks or reverse bends.
INCORRECT
CORRECT
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2. Ferrule size,
length Although fer-
rule diameters arefairly universal for a
given rope size,
length is not. It's best
to know and specify
the ferrule size and
length. Shovels typi-
cally use shorter fer-
rules due to space
limitations. Longer
ferrules may not fit in
the sockets properly.
3. Dead wraps Toprevent overloading
the ferrules, the system depends on the friction
provided by the dead wraps on the drum. As such,
ropes should be purchased that provide 1.5-2.0
dead wraps for shovels and 2.5-3.0 dead wraps for
walking draglines on the drum when the most pos-
sible rope is reeled out. This is easy to check by
visual observation.
4. Rope length In most applications where fer-rule beckets are used, it is difficult to equalize therope lengths. Unequal lengths, however, will pro-
duce significantly unequal loading and shorter
rope life. It is critical that hoist ropes that use fer-
rule becket fittings be replaced in sets. It is also
critical that the lengths of the two hoist ropes in a
replacement set be kept within the tight tolerance
specified (Figure 21).
Wedge Sockets
Wedge sockets should be used only with standard6 to 8 strand wire rope. For rope larger than 9/16
in. (14.3 mm) in diameter, use the next larger size
socket. For example, a 9/16 in. rope requires a 5/8
in. (15.9 mm) wedge socket.
Page 23
5 - Receiving and Handling Wire Rope
MATCHED SET TOLERANCE 0.50"
WIRE PULLING LOOP FERRULE BECKET
Figure 21 For matched sets of hoist ropes with ferrule becket end fittings, the rope lengths must be kept
within the tolerance specified (typically, 0.50").
Figure 20 End preparations, or beckets, are used when another rope is needed
to pull the operating rope into place. Four basic types of beckets are shown.
PAD EYE LINK BECKET TAPERED &WELDED END
TAPERED ENDWITH LOOP
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The tail length (Figure 22) should be at least 6
rope diameters but never less than 6 in. (152 mm).
For example, for a 2 in. (51 mm) rope: Tail Length
= 2x6 = 12 in. (304.8 mm).
Note: Always remove the end preparationbefore seating the wedge in the socket. Thisallows the strand and wires to slide relative toeach other as they conform to the tight radius of
the wedge.
Align the live end of the rope with the center line
of the socket pin. Secure the dead end with proper-
ly sized U-bolt or fist grip clips (Figure 23). Never
attach the dead end of the rope to the live rope.
Poured Spelter SocketsSpelter sockets make highly efficient end termina-
tions, particularly for large diameter ropes and
boom pendants.
The socket is attached to the rope by inserting the
broomed out end of the rope or structural strand
into the cone-shaped socket and pouring molten
zinc into the socket and letting it cool (Figure 24).
However, due to the rigidity of the attachment, the
ability of the rope or strand to bend or adjust at the
fitting is extremely limited. Thus, high stress
caused by vibration is created at the point where
the wires enter the socket. This calls for frequent
inspection for broken wires or strands at this point.
Be sure to check the socket manufacturers policy
regarding resocketing.
Page 24
PEAK PERFORMANCE PRACTICES WIRE ROPE
Figure 22 A wedge socket is easy to use but it is critical
that the rope is attached correctly. Never attach the dead end
of the rope to the live rope. If a rope clamp is used it should
not be tightened until after the wedge is seated in the socket.
TAIL
LENGTH
CORRECT INCORRECT
Figure 23 Wire rope clips are available in two
basic styles: U-bolt and fist grip. Both provide the
same efficiency.
Figure 24 Molten zinc is commonly used to
secure wire rope to a spelter socket. Some manu-
facturers use specially formulated resin instead.
U-BOLT CLIP FIST GRIP CLIP
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Boom and mast support pendants are normally
made of galvanized structural strand with non-pre-
formed wires. The outer layers of these wires arelaid in alternating directions, i.e. left lay and right
lay, for torque-balanced construction. This is
called cross-laid strand (Figure 25). In some
strand constructions the innermost wires may be
laid in a parallel arrangement called parallel con-
tact core. It offers more contact area between
adjacent wires to handle the higher internal strand
pressures toward the strand center (Figure 26).
End terminations are usually poured spelter sock-
ets.
Structural strand is prestretched to minimize addi-tional stretching during operation. To ensure that
each assembly is measured to the same length, it
is measured before prestretching and again after
prestretching, under load.
However, because used strand may sustain some
additional stretch, it will tend to be slightly longer
than new, unused strand. Pairing a new pendant
with a used one may cause the new pendant to
carry a larger load, making it likely to fail before
the used pendant. As a result, boom and mast pen-
dants should always be replaced in full sets,unless a true equalizing link arrangement is used.
Because of the high stresses placed on the strand
where it enters the socket, fatigue breaks are most
likely to occur at that point. Be sure to inspect this
area carefully on a regular basis and lubricate
every three months through the lube fittings pro-
vided.
Page 25
6 - StructuralStrand BoomPendants
Figure 26 Parallel contact core construction
increases the contact between the core and adja-
cent wires to handle the higher internal strand
pressures toward the strand center.
Figure 25 Cross-laid strand construction helpsbalance torque forces in structural strand.
CORE
CORE
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Assuming there is no damage to the rope in ship-
ping, handling and storage, a wire ropes service
life is affected from the time it is installed.Improper installation or securing of its end termi-
nations can reduce its life. Be sure to follow the
proper procedures and use properly sized sheaves.
Break in new wire rope Any time a newwire rope is installed, it needs to be broken in
properly. Start the equipment and allow the rope
to run through an operating cycle at slow speed
with no load.
Carefully observe all the working parts of the sys-
tem, including sheaves, drums and rollers, to seethat the rope runs smooth-
ly and without obstruc-
tion. If any problem is
encountered, correct it
before proceeding any
further.
Repeat this process sev-
eral times, gradually
increasing the load
and speed. This
allows the
rope to
stretch and the wires and strands to seat in and
adjust to normal operating conditions.
Inspect twin sheaves for uneven wear Onshovels and some draglines, both grooves of twin
sheaves should be the same depth. If one groove is
deeper than the other, rope performance and ser-
vice life will decrease and sheave wear will
increase. Check the equipment manufacturers tol-
erances for groove wear and repair or replace the
sheave as needed.
Keep martensite in check Martensite is ahard-to-see wire surface condition that leads to
broken wires. It is formed by the very localizedhigh heat of friction on the crowns of
wire rope followed by rapid cool-
ing of the wires beneath them.
The formation of martensite
can be prevented by using
properly sized sheaves,
limiting sheave over-
spinning and avoid-
ing digging tech-
niques that
Page 27
7 - RecommendedPractices for ExtendingWire Rope Life
Figure 27 Wire rope suppliers carefully wrap rope on reels to insure damage-free rope
shipments.
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produce high friction contact situations or exces-
sive rope oscillations. Also avoid rope contact
with hard objects such as rock, especially whenoperating at high line speeds.
Keep wire ropes properly lubricatedThis allows the wires and strands to adjust to
changing loads and prevents corrosion. Lubricate
the ropes as needed with each inspection. Where
sheave overspinning occurs it is a good practice to
lubricate the sheave groove with an open gear type
of lubricant to dampen the relative motion and
prevent Martensite formation in the rope wires.
Also lubricate pendant sockets every threemonths. Some larger diameter pendant sockets
have a lube fitting in the zinc/resin. These fittings
should also be lubricated at no more than three-
month intervals. For shovels equipped with rope-
operated crowd and retract functions, refer to the
manufacturers instructions for maintenance and
replacement procedures and safety precautions.
Shovels
The leading cause of rope failures on shovels is
drum dampening, i.e. the shock created in slack
rope when sudden loading occurs. Depending on
the style of bail and equalizer, letting the bail
go slack and then taking it up too rapidly
can cause excessive
vibration in the rope.
This is especially
true on bailless dip-
pers. Vibration can
be minimized bystarting the digging
cycle slowly and
loading the rope
gradually while
increasing the ten-
sion on the rope.
Adjusting the digging angle can also reduce the
load on wire rope. Loading increases with the dig-
ging angle and crowd distance (Figure 28).
At a digging angle of 15 it takes 1.035 times as
much power, or 3.5% more, to lift a given load as
it does directly below the boom point. At an angle
of 45 it takes 41.4% more power. And at an angle
of 60 it takes twice as much power.
Digging as low under the boom point as possible
helps to reduce rope stress and extend the useful
life of wire rope.
Page 28
PEAK PERFORMANCE PRACTICES WIRE ROPE
4100A
LC ROTATIONLC ROTATION
Figure 28 The load on the hoist rope increases with the digging angle. At a dig angle of
15, it takes 3.5% more power to lift a load as it does directly beneath the boom point. At
60, twice as much power is required.
60
45
15 30
0
Dig Angle Affects Power RequirementsDig Angle Power Required
to Lift Load*0 100%15 103.5%30 115.4%45 141.4%60 200%
*As a percentage of load
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DraglinesAs with shovels, the most efficient digging range
is directly beneath the boom point (Figure 29).
Casting the bucket beyond this point increases the
stress and load on the rope. As the bucket is pulled
closer to the dragline, digging efficiency decreases
and the load on the ropes increases, including the
dump rope(s).
Most of the wear on dragline ropes occurs in the
areas that run through the fairleads, about one-
third to one-half the full length of the rope.
Reversing the drum and bucket ends of the rope
places worn areas of the rope in areas less vulner-
able to further wear, and vice versa.
Some additional wear on drag ropes occurs at the
base of the wedge socket. Resocketing the rope
when there are six broken wires at the drag sock-
et, or at approximately every 1/5 of its service life,
until the rope becomes too short to use will maxi-
mize its useful life.
A heavy application of "sticky" lubricant such as
open gear lubricant in the grooves of the vertical
fairleads can help the rope start and stop the
sheaves and limit the formation of martensite in
the wires.
Used hoist ropes can be salvaged for reuse as drag
ropes by cutting to length sections of used rope
that pass inspection, if the ropes are the same
diameter. Likewise, suitable sections of old hoist
and drag ropes can be used as dump ropes if they
are the right size.
Similarly, dragline rope life can be extended by
reversing them end for end when the ropes reach
approximately 40 to 50 percent of their expected
service life.
Page 29
7 - Recommended Practices for Extending Wire Rope Life
Figure 29 As the bucket is drawn closer to the dragline, the power required to lift the same load increases.
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BENDABILITY The ability of a rope to bend
in an arc.
BOOM PENDANT A non-operating wire rope
or structural strand secured with end terminations
to provide structural support for the boom.
BRIGHT ROPE Rope that is made fromuncoated wires.
BROOM The spreading out of a rope's strands
and individual wires at the rope's end.
CATENARY A curve formed by a strand or
wire rope when supported horizontally between
two fixed points, e.g., the main spans on a suspen-
sion bridge.
COMPACTED STRAND A type of high per-
formance wire rope whose exterior strands are
purposely flattened to increase the ropes exposedsurface; compacting enhances both fatigue resis-
tance and crushing resistance.
CORE The central part of a rope that serves as
the ropes foundation.
CORRUGATION A wrinkling or shaping into
a series of ridges or furrows.
CRUSHING RESISTANCE A ropes ability
to retain its round shape when outside forces act
on it, especially when multiple wraps or layers of
rope are wound on a reel or drum.DESIGN FACTOR The ratio of a ropes nom-
inal or catalog strength to its anticipated maxi-
mum load in operation.
DOG-LEG A permanent bend or kink in a
wire rope caused by mishandling or improper
operation.
DRUM A cylindrical grooved or smooth barrel
on which wire rope is spooled for storage or oper-
ation.
END PREPARATION A treatment of the end
of a wire rope to prepare it for being pulled by
another rope into a tight opening as in a drum.
END TERMINATION The treatment at the
end of a rope designed to be the permanent end
termination that connects the rope to the load.
FATIGUE RESISTANCE A ropes ability to
withstand repeated bending under stress, as when
passing over a sheave; a relatively large number of
wires in a ropes design improves its bendability.
FILLER WIRE Small wires used in a strand
as spacers between an inner and outer layer of
larger wires.
FLEET ANGLE That angle between the
rope's position at the extreme end wrap on a drum,
and a line drawn perpendicular to the axis of the
drum through the center of the nearest fixed
sheave. See DRUM and SHEAVE.
INDEPENDENT WIRE ROPE CORE (IWRC)
A complete wire rope in its own right used as
the core of a larger wire rope.
INTERNALLY LUBRICATED Wire rope or
strand that has all its components coated with
lubricant.
LANG LAY A method of wire rope construc-
tion in which the crowns of the wires in a strand
appear to be at an angle to the ropes axis.
LAY The pattern in which a strands wires are
helically wrapped around the central wire and the
strands are wrapped around the ropes central
core.
Page 31
Glossary ofCommon Terms
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PEAK PERFORMANCE PRACTICES WIRE ROPE
Page 32
LAY LENGTH The distance measured paral-
lel to the ropes axis in which a single wire makes
one complete helical convolution about the core;also called pitch.
PEENING A flattening on the outer surface of
a wire rope due to the rope contacting a solid
object.
PITCH An alternate term for lay length.
REGULAR LAY A method of wire rope con-
struction in which the crowns of the wires in a
strand appear parallel to the ropes axis.
RESERVE STRENGTH The percentage of a
ropes nominal strength remaining with the ropes
outer layer of wires removed.
SEALE A strand construction in which two
layers of wires, equal in number, are wrapped
around the center wire; the large outer wires rest
in the valleys of the inner layer of wires.
SEIZING A method of preparing the ends of a
rope for installation; soft wire or strand is bound
around the ends the rope to prevent it from flatten-
ing, distorting or unraveling; also called whipping.
SHEAVE A grooved pulley for use with wire
rope.
STRAND A grouping of wires laid in a helical
pattern about a central wire; groups of strands are
laid about the ropes core.
STRETCH The lengthening of a rope under
load.
SWAGE A method that employs hammers to
compact wire rope strands and fittings.
WARRINGTON A strand construction inwhich one of the layers, usually the outer layer, is
made up of alternating large and small wires.
WIRE STRAND CORE (WSC) A wire
strand used as the foundation of a wire rope.
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Page 33
Abrasion resistance . . . . . . . . . . . . . . . . . . . . . . . . .11
Boom Pendants . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
Breaking strength . . . . . . . . . . . . . . . . . . . . . . . .13,16
Broken wires . . . . . . . . . . . . . . . . . . . . . . . . . . .17-19
Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . .11-14
Classifications . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-8
Compacted strand . . . . . . . . . . . . . . . . . . . . . . . .12-13
Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-8
Cores . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Corrugation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20Cross-laid strand . . . . . . . . . . . . . . . . . . . . . . . . . . .25
Crushing resistance . . . . . . . . . . . . . . . . . . . . . . . . .14
D/d ratio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Dead wraps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Design factor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
Draglines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29
End preparations . . . . . . . . . . . . . . . . . . . . . . . . . . .22
Extending wire rope life . . . . . . . . . . . . . . . . . . .27-29
Extra extra improved plow (EEIP or XXIP) . . . . . . . .4
Extra improved plow (EIP) . . . . . . . . . . . . . . . . . . . .4
Fatigue resistance . . . . . . . . . . . . . . . . . . . . . . . .11-12
Ferrule becket . . . . . . . . . . . . . . . . . . . . . . . . . .22-23
Fiber core (FC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Filler wire (FW) . . . . . . . . . . . . . . . . . . . . . . . . . . .6-7
Finishes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Fist grip clips . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
Flattened strand . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
Grades . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Improved plow (IP) . . . . . . . . . . . . . . . . . . . . . . . . . .4
Independent wire rope core (IWRC) . . . . . . . . . . .3,13
Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15-20
sheaves and drums . . . . . . . . . . . . . . . . . .19-20
Inspection checklist . . . . . . . . . . . . . . . . . . . . . . . . .18Lay
lang . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-6
left lang lay (LLL) . . . . . . . . . . . . . . . . . . . . .4
left regular lay (LRL) . . . . . . . . . . . . . . . . . . .4
regular . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-5
right lang lay (RLL) . . . . . . . . . . . . . . . . . . . .4
right regular lay (RRL) . . . . . . . . . . . . . . . . . .4
Lay length . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
Link Becket . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Lubrication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29
Martensite . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
Measurements . . . . . . . . . . . . . . . . . . . . . . . . . .15-16
Metal loss . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Mild plow steel (MP) . . . . . . . . . . . . . . . . . . . . . . . .4
Minimum acceptance strength . . . . . . . . . . . . . . . . .13
Minimum catalog strength . . . . . . . . . . . . . . . . . . . .16
Multiple operation (2-Op) . . . . . . . . . . . . . . . . . . . .7
Nominal strength . . . . . . . . . . . . . . . . . . . . . . . . . . .13
Non-preformed wire . . . . . . . . . . . . . . . . . . . . . . . . .6Pad Eye . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Parallel contact core . . . . . . . . . . . . . . . . . . . . . . . .25
Peening . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Preformed wire . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Plastic coated rope . . . . . . . . . . . . . . . . . . . . . . . . . .13
Pull-off strength . . . . . . . . . . . . . . . . . . . . . . . . . . .22
Reserve strength . . . . . . . . . . . . . . . . . . . . . . . . . . .14
Retirement . . . . . . . . . . . . . . . . . . . . . . . . . . .16-17,19
Seale (S) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Selection guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Service life . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Sheave groove gauge . . . . . . . . . . . . . . . . . . . . .19-20
Shovels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
Single layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-7
Spelter Sockets . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
Storing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
Strands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
Structural strand . . . . . . . . . . . . . . . . . . . . . . . . . . .25
Swaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
Tapered and Welded End . . . . . . . . . . . . . . . . . . . . .23
Terminations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
U-Bolt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24Unreeling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
Warrington (W) . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Warrington Seale (WS) . . . . . . . . . . . . . . . . . . . . . . .7
Wedge Sockets . . . . . . . . . . . . . . . . . . . . . . . . . .23-24
Winding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
Wire strand core . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Wires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
X chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
Index
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P&H gratefully acknowledges the Wire Rope Technical Board and its Wire Rope Users Manual,
Third Edition for permission to reproduce source material for this publication. We also thank
Bridon American Corp. and Wire Rope Industries, Ltd. for their kind assistance.
Suggestions, Ideas?It is our hope you have found this handbook informative and helpful, but we recognize that every mine has its own
methods of operation and unique set of equipment requirements, and that no single handbook can answer everyones
needs.
If you have any suggestions regarding how we can improve this book, we would be pleased to consider them for
inclusion in a future edition.
Please e-mail your comments and suggestions to P&H MinePro Services at [email protected], or call us at
(414) 671-4400 and ask for Marketing Communications.
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7/27/2019 2) Peak Performance Practices - Wire Rope
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In addition to a full complement of wire rope from the industrys leadingmanufacturers, P&H offers comprehensive wire rope services, including:
Wire rope recommendations based on applications analysis
Wire rope installation
Wire rope handling and maintenance training
Sheave and drum re-grooving/replacement
Wire rope inspection and failure analysis
P&H TripRite dipper trip control system
For further information, contact your local P&H MinePro Services representative or call 1-888-MINEPRO. Outside
the U.S. and Canada, phone (414) 671-4400 or fax (414) 671-7785. Visit us on the internet at www.minepro.com.
Serving All Your Wire Rope Needs