ISO 19426-7:2021

INTERNATIONAL ISO
STANDARD 19426-7
First edition
2021-05
Structures for mine shafts —
Part 7:
Rope guides
Structures de puits de mine —
Partie 7: Guides-câbles
Reference number
©
ISO 2021
© ISO 2021
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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ii © ISO 2021 – All rights reserved

Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols . 4
5 Materials . 8
6 Disturbing actions . 8
6.1 Coriolis force . 8
6.2 Aerodynamic loads . 9
6.2.1 Steady state . . 9
6.2.2 Buffeting . 9
6.2.3 Air density .10
6.3 Rope torque .10
6.3.1 Head rope torque .10
6.3.2 Tail rope torque . .11
6.3.3 Torque applied by multiple ropes .11
6.4 Eccentric conveyance loading .11
6.5 Winder emergency braking .12
6.6 Thermal actions on headframe .12
6.7 Wind load on conveyances.12
7 Restoring forces .12
7.1 Rope guide tension .12
7.2 Rope guide stiffness .13
7.2.1 Stiffness of rope guides .13
7.2.2 Stiffness of head and tail ropes .13
8 Conveyance trajectory .15
8.1 Simulation of conveyance behaviour .15
8.2 Combination of actions .15
9 Design procedure .15
9.1 Function of rope guides .15
9.2 Risk assessment .15
9.3 General design procedure .15
9.4 Simple design procedure .16
9.4.1 Limits on parameters .16
9.4.2 Design requirements .16
9.5 Comprehensive design procedure .16
10 Minimum clearances .17
10.1 Design clearances .17
10.2 Dynamic displacement envelope .17
10.3 Reduced dynamic clearances .17
10.4 Use of rubbing ropes .18
11 Construction and installation tolerances .18
11.1 Shaft vertical cylinder diameter .18
11.2 Tolerance of associated structures .18
11.3 Tolerance on rope guide tension .18
11.4 Commissioning .18
11.4.1 Commissioning procedure .18
11.4.2 Components of the commissioning procedure .18
12 Other design considerations .19
12.1 General .19
12.2 Loading and unloading of conveyances .19
12.3 Accessing intermediate levels .19
12.4 Number of rope guides .19
12.5 Rope guide positions .19
12.6 Rope guide construction .19
12.7 Rope guide tension and factor of safety .20
12.8 Rope guide attachments .20
12.9 Shafts with more than one winder .20
12.10 Design life .20
12.11 Rope guide tensioning .20
12.11.1 Gravity tensioning devices .20
12.11.2 Hydraulic tensioning devices .20
13 Assessment of existing installations .21
13.1 General .21
13.2 Application of measurements .21
13.3 Upgrades or modifications .21
14 Inspection and maintenance .22
14.1 Deterioration mechanisms .22
14.1.1 General.22
14.1.2 Wear .22
14.1.3 Corrosion .22
14.1.4 Mechanical damage .22
14.1.5 Broken wires .22
14.2 Inspections .22
14.2.1 General.22
14.2.2 Inspection intervals .22
14.2.3 Visual inspection .22
14.2.4 Non-destructive inspection .22
14.3 Maintenance actions .23
14.3.1 Maintenance intervals .23
14.3.2 Lubrication .23
14.3.3 Rope turning and rope lifting .23
14.3.4 Equalisation of hoist rope tensions .23
14.4 Rope guide discard criteria .23
14.5 Rope guide attachments .23
Annex A (informative) Load combinations and displacement multipliers .24
Annex B (informative) Introduction to Annexes B to F, and basic parameters .26
Annex C (informative) Preliminary aerodynamic coefficients .35
Annex D (informative) Rope torque factors .44
Annex E (informative) Rope guide stiffness and tension .46
Annex F (informative) Approximate calculation of conveyance displacement .50
Bibliography .53
iv © ISO 2021 – All rights reserved

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/
iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 82, Mining.
A list of all parts in the ISO 19426 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
Introduction
Many mining companies, and many of the engineering companies that provide designs for mines,
operate globally so ISO 19426 was developed in response to a desire for a unified global approach to
the safe and robust design of structures for mine shafts. The characteristics of ore bodies, such as
their depth and shape, vary in different areas so different design approaches have been developed and
proven with use over time in different countries. Bringing these approaches together in ISO 19426 will
facilitate improved safety and operational reliability.
The majority of the material in ISO 19426 deals with the loads to be applied in the design of structures
for mine shafts. Some principles for structural design are given, but for the most part it is assumed that
local standards will be used for the structural design.
vi © ISO 2021 – All rights reserved

INTERNATIONAL STANDARD ISO 19426-7:2021(E)
Structures for mine shafts —
Part 7:
Rope guides
1 Scope
This document specifies the design loads and the design procedures for the design of rope guides
and rubbing ropes used for guiding conveyances and preventing collisions in vertical mine shafts for
permanent operations. It covers personnel and material hoisting, as well as rock hoisting installations.
There are no fundamental limitations placed on the size of conveyances, the hoisting speeds, shaft
layout configurations, or the shaft depth.
This document can be applicable to shaft sinking operations when kibbles run on the stage ropes.
There are many reasons, based on technical, timing, and cost factors, why rope guides are selected
or not for a particular application, following careful assessment at feasibility stage of any project
where rope guides are considered. This document provides some comments regarding the advantages
and disadvantages of using rope guides compared to rigid guides, and specific design aspects for
consideration when using rope guides. However, it is primarily intended to provide the technical
information required to ensure good engineering of shafts where rope guided hoisting is the chosen
solution.
This document does not cover matters of operational safety.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 19426-1, Structures for mine shafts — Part 1: Vocabulary
ISO 19426-2, Structures for mine shafts — Part 2: Headframe structures
ISO 19426-5, Structures for mine shafts — Part 5: Shaft system structures
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 19426-1 and the following
apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org
3.1
cheeseweight
stack of weights, usually steel castings, suspended from the bottom of a rope guide forming a dead
weight tensioning system
3.2
direct collision
event in which a conveyance strikes another conveyance or some other surface that is essentially
transverse to the direction of travel of the conveyance
Note 1 to entry: See Figure 1 a).
3.3
oblique collision
event in which a conveyance strikes a shaft side wall or some other surface that is oriented essentially
parallel with the direction of travel of the conveyance
Note 1 to entry: See Figure 1 b).
a) Direct collision
b) Oblique collision
Figure 1 — Schematic of possible collision types
3.4
design clearance
static clearance
nominal distance between different conveyances, or between conveyances and fixed objects, in the
shaft, as shown on the design drawings
3.5
design location
intended location of elements of the rope guided hoisting installation, as shown on the design drawings
3.6
displacement multiplier
factor by which the predicted conveyance lateral displacement is multiplied to make statistical
allowance for inaccuracies in simulation and aerodynamic coefficients and construction tolerances
2 © ISO 2021 – All rights reserved

3.7
dynamic clearance
minimum distance between different conveyances, or between conveyances and fixed objects, in the
shaft during hoisting in the shaft, which is equal to the design clearance (3.4) less the maximum dynamic
displacement (3.8)
3.8
dynamic displacement
lateral displacement of conveyances while travelling in the shaft
3.9
design dynamic displacement
lateral dynamic displacement (3.8) of conveyances while travelling in the shaft multiplied by the
displacement multiplier (3.6), which makes provision for simulation uncertainties and construction
inaccuracies
3.10
reduced dynamic clearance
minimum distance between different conveyances, or between conveyances and fixed objects, in the
shaft during hoisting in the shaft, which is equal to the design clearance (3.4) less the design dynamic
displacement (3.9)
3.11
entry point
position at which a conveyance enters fixed guides at the top and bottom ends of the hoisting cycle, and
at any intermediate stations
3.12
guide block
guide bush
guide slipper
attachment of a conveyance to the rope guides
Note 1 to entry: The guide block is usually made in two halves to bolt around the rope guide, and it has a guide
block liner forming the rubbing surface on the rope guide.
3.13
intermediate loading station
loading station between bank level or a tipping station at the top of the shaft and a loading station at the
bottom of the shaft, or any loading station located more than 100 m below the top anchor point of the
rope guides or more than 100 m above the bottom anchor point of the rope guides
3.15
rope guide shoe
mounting to secure the guide block (3.12) through which the rope guide passes to the conveyance
3.16
rubbing block
fixed guide slippers
contact point between a conveyance and the fixed guides at top and bottom of winding cycle, which can
run within or outside the fixed guide
Note 1 to entry: Where the fixed guides are located close to the rope guides, the rubbing block can also serve the
purpose of the rope guide shoe.
3.17
rubbing rope
rope located between conveyances running on rope guides, intended to deflect conveyances away from
each other, thereby reducing the severity of a possible collision
3.18
vertical shaft cylinder
maximum circular cylinder, clear of any obstructions, that fits within the excavated mine shaft and
constructed infrastructure
3.19
winder emergency braking
winder trip-out
braking of the winder under emergency conditions, such as loss of electrical power, detection of over-
tension or under-tension on the hoist ropes, or accident to shaft signal
4 Symbols
a Conveyance acceleration, m/s
A Area of the relevant side of a conveyance, m
C
A Cross sectional steel area of a single head rope, m
R
A , A Area of specified portions of a shaft cross-section, m
1 2
b Thickness of skip stiffeners, m
B Distance between the conveyance centre of gravity and the geometrical centre of the set of
E
rope guides, guiding that conveyance, m
B , B Plan dimensions of a conveyance, m
X Z
C , C Basic aerodynamic lateral force coefficient in appropriate direction, taken as 0,018
BX BZ
C Aerodynamic force coefficient
L
C , C Aerodynamic lateral force coefficient in appropriate direction
LX LZ
C Conveyance passing buffeting force coefficient
LP
C Torque factor applied to head ropes
Q
-1
C Coefficient of thermal expansion of the rope guide, ˚C
T
d Shaft diameter, m
S
d Rope diameter, m (note that this is usually given in mm in hoist rope catalogues)
R
D Lateral conveyance displacement due to steady state aerodynamic force, m
A
D Lateral conveyance displacement due to buffeting forces, m
B
D Lateral conveyance displacement due to Coriolis force, m
C
D Lateral conveyance displacement at the bottom of the conveyance due to conveyance eccen-
EB
tricity with respect to the head rope attachment point, m
D Lateral conveyance displacement at the centre of gravity of the conveyance due to convey-
EC
ance eccentricity with respect to the head rope attachment point, m
D Lateral conveyance displacement at the top of the conveyance due to conveyance eccentricity
ET
with respect to the head rope attachment point, m
D General lateral displacement of the centre of gravity of a conveyance in a shaft, m
G
4 © ISO 2021 – All rights reserved

D' General lateral displacement of the geometric centre of the set of rope guides guiding one
G
conveyance in a shaft, m
D Amplitude of initial rope guide motion prior to hoisting of a conveyance, m
I
D Nominal design movement allowance between a conveyance and other objects in a shaft, m
M
D Nominal design clearance between a conveyance and other objects in a shaft, m
N
D Minimum dynamic clearance, m
O
D Total combined lateral displacement of a conveyance, m
P
D Lateral conveyance displacement due to initial rope guide motion, m
R
D Recommended tolerance allowance, m
X
D Lateral displacement due to yaw rotation of the conveyance in the shaft, m
Y
E Elastic modulus of the head rope or the rope guide, Pa
S
F Steady state aerodynamic force acting on a conveyance, N
A
F Coriolis force acting on a conveyance, N
C
F Peak force during buffeting of a conveyance, N
P
F General lateral force applied to a conveyance, N
X
F General moment applied about the centre of gravity of a conveyance, Nm
Y
g Acceleration due to gravity, m/s
h Body height of a conveyance, m
h Ventilation opening height on a cage, m
H Overall height of a conveyance, m
H Height from the conveyance centre of gravity to the top of the conveyance, m
C
I Mass moment of inertia of a conveyance about the vertical centroidal axis, kgm
C
K Lateral stiffness at conveyance elevation, of a single head rope, N/m
H
K Lateral stiffness at conveyance elevation, of the set of ropes attached to one conveyance,
L
N/m (this includes the rope guides, the head ropes, and where applicable the tail ropes)
K Lateral stiffness at conveyance elevation, of a single rope guide, N/m
R
K Lateral stiffness at conveyance elevation, of a single tail rope, N/m
T
K Rotational stiffness at conveyance elevation, of the set of ropes attached to one conveyance,
θ
Nm/rad
L Overall length of the rope guides, m
L Head rope length between the conveyance and the sheave, m
H
L Tail rope length between the conveyance and the bottom sheave, m
T
L Rope guide length between the top of a conveyance and the top anchor point, m
L Rope guide length between the bottom of a conveyance and the bottom anchor point, m
m Conveyance mass, including mass of rope attachments and payload, kg
C
m Mass per unit length of a single head rope, kg/m
H
m Payload mass, kg
P
m Mass per unit length of a single rope guide, kg/m
R
m Mass per unit length of a single tail rope, kg/m
T
M Overturning moment due to eccentric loading, Nm
O
n An integer greater than 1
n Number of head ropes for a single conveyance
H
n Number of rope guides guiding a single conveyance
R
n Number of tail ropes for a single conveyance
T
Q Rope torque applied to a conveyance, Nm
Q Rope torque from rope i applied to a conveyance, Nm
i
r Ratio of acceleration time to natural period
t
R Ratio of first force peak to second force peak used for buffeting as two conveyances pass
each other, taken as 1,5
R Blockage ratio for two conveyances in a shaft
B
R Gap ratio between conveyances in a shaft
G
R , R Distance and width ratios for air inflow and outflow buffeting
D W
R Shape factor for air inflow and outflow buffeting
S
S Conveyance size factor
A
S , S Sidewall proximity factors
PX PZ
S , S Conveyance shape factors in X- and Z-directions
SX SZ
t Time, s
t Time taken for two conveyances to pass each other in a shaft, s
P
T Tension in a rope, N
T Rope guide tension at the bottom anchor point, N
BOT
T Head rope tension at a conveyance, N
H
T’ Increased head rope tension at a conveyance, N
H
T Rope guide tension at conveyance elevation in the shaft, N
L
T Rope guide tension at mid-depth of the shaft, N
M
6 © ISO 2021 – All rights reserved

T Tail rope tension at a conveyance, N
T
T Rope guide tension at the top anchor point, N
TOP
U Horizontal dimensions of the air inflow or outflow duct, m
i
v Horizontal component of airflow velocity in a station or side duct, m/s
D
v Hoisting speed of a conveyance, m/s
H
v Velocity of a conveyance relative to ventilation airflow speed, m/s
R
W Total eccentric payload applied to a conveyance, N
w Width of the skip stiffener, m
x , z Horizontal distances between the conveyance centre of gravity and the geometric centre
C C
of the shaft, m
x , z Horizontal distance between the conveyance centre of gravity and the centre of hoist rope
HC HC
attachment, m
x , z Horizontal distance between the conveyance centre of gravity and the centre of hoist rope
Hi Hi
number i, m
x , z Horizontal distance between the payload centre of gravity and the centre of hoist rope
P P
attachment, m
x , z Horizontal distance between the conveyance centre of gravity and the centre of rope guide
Ri Ri
number i, m
x , z Horizontal distance between the conveyance centre of gravity and the centre of tail rope
TC TC
attachment, m
x , z Horizontal distance between the conveyance centre of gravity and the centre of tail rope
Ti Ti
number i, m
Y Vertical dimensions of the air inflow or outflow duct, m
i
α A dynamic magnification factor
α Winder emergency braking magnification factor for torque and eccentricity
T
β Tilt angle of a conveyance subjected to an eccentric payload, rad
β , β Angles of the top or bottom of a skip, rad
1 2
Δ Change in ambient temperature, ˚C
C
Δ Change in rope guide tension, N
T
θ General yaw rotation of the conveyance in the shaft, rad
ρ Air density, kg/m
γ Displacement multiplier
R
ϕ Latitude of the mine shaft site, positive north and south of the equator, deg
ϕ Angle of the air inflow or outflow duct, rad
A
-5
ω Radial rotation velocity of the earth, 7,27x10 rad/s
E
ω Fundamental radial frequency of oscillation of the rope guides, rad/s
R
ω Fundamental radial frequency of oscillation of the rope guides with the conveyance, rad/s
RC
ω Fundamental radial frequency of yaw rotation of the rope guides with the conveyance, rad/s
RCY
ω Fundamental natural frequency of vertical motion of the conveyance suspended from the
VT
head ropes, rad/s
5 Materials
The materials used for rope guides and rubbing ropes shall be materials having guaranteed mechanical
properties. It is most common to use high strength steel wire ropes complying with EN 12385-6 and
EN 12385-7.
6 Disturbing actions
6.1 Coriolis force
The Coriolis force always acts in a westerly direction for an ascending conveyance, and in an easterly
direction for a descending conveyance. The Coriolis force acts on all the moving masses, that is the
mass of the conveyance and the head and tail ropes.
The Coriolis force results from the rotation of the earth and masses moving in a vertical direction. The
Coriolis force F is defined as:
C
Fm=2 v ωφcos (1)
ch E
where m can be taken as:
L L
H T
mm=+nm +nm (2)
cH H TT
where
L is the head rope length between the conveyance and the sheave, m;
H
L is the tail rope length below the conveyance, m;
T
m is the conveyance mass, including mass of rope attachments and payload, kg;
C
m is the hoist rope unit mass, kg/m;
H
m is the tail rope unit mass, kg/m;
T
n is the number of hoist ropes;
H
n is the number of tail ropes;
T
v is the hoisting speed of conveyance, m/s;
H
-5
ω is the radial rotation velocity of the earth, 7,27x10 rad/s;
E
ϕ is the latitude of the mine shaft site, positive whether north or south of the equator.
8 © ISO 2021 – All rights reserved

6.2 Aerodynamic loads
6.2.1 Steady state
The steady state aerodynamic force acting on a conveyance F is defined as:
A
FC= ρvA (3)
AL RC
where
C is the aerodynamic lateral coefficient, but not less than 0,02;
L
ρ is the air density, which may be approximated using the values in Table 1, kg/m ;
v is the conveyance velocity relative to the ventilation airflow, m/s;
R
A is the area of the relevant side of the conveyance, m .
C
Values of C should be obtained from an appropriate level of accuracy of computational fluid dynamics
L
analysis. However, for preliminary design only, the values may be obtained from Annex C. When C
L
exceeds 0,02 it shall be taken to act in a specific direction arising from the aerodynamic flow around
the conveyance. When C is taken as 0,02 it shall be taken to act in either direction.
L
Note that different values of F act on a conveyance in each of the two horizontal directions.
A
6.2.2 Buffeting
6.2.2.1 Buffeting force when two conveyances pass each other
The amplitude and time variation of the buffeting force when two conveyances pass each other in the
shaft should be obtained from computational fluid dynamics analysis.
The amplitude of the buffeting force F is defined as:
P
FC= ρvA (4)
PLPH C
where
C is the buffeting force coefficient (see Annex C);
LP
ρ is the air density, which may be approximated using the values in Table 1, kg/m ;
v is the relative passing speed, m/s;
H
A is the area of the relevant side of the conveyance, m .
C
Values of C should be obtained from an appropriate level of accuracy of computational fluid dynamics
LP
analysis. However, for preliminary design only, the values may be obtained from Annex C.
The time variation of this buffeting force should be obtained from computational fluid dynamics
analysis. However, for preliminary design only, the time variation may be obtained from Annex C.
6.2.2.2 Buffeting in the wake of a leading conveyance
The amplitude and time variation of the buffeting force on a conveyance following closely behind another
conveyance, and travelling in the same direction in the shaft, should be obtained from computational
fluid dynamics analysis.
When winders are controlled in such a manner as to ensure that conveyances cannot travel closer than
five conveyance lengths behind another conveyance, this action can be neglected.
6.2.2.3 Buffeting force when conveyance passes inflow or outflow of air
The amplitude and time variation of the buffeting force induced when a conveyance passes an area
of air inflow or air outflow in the shaft should be obtained from an appropriate level of accuracy of
computational fluid dynamics analysis.
The amplitude of the buffeting force F is defined as:
P
FC= ρvA (5)
PLPD C
where
C is the buffeting force coefficient (see Annex C);
LP
ρ is the air density, which may be approximated using the values in Table 1, kg/m ;
v is the horizontal component of airflow velocity in the station or side duct, m/s;
D
A is the area of the relevant side of the conveyance, m .
C
The time variation of this buffeting force may be taken as described in Annex C.
6.2.3 Air density
The air density may be assumed to be constant throughout the depth of the shaft. The air density should
be taken as the average of the air density at the top of the shaft and the air density at the bottom of the
shaft, taking account of the ventilation pressure, altitude above sea level, the ambient air temperature
and the humidity. The air density may be obtained from Table 1.
Table 1 — Values of dry air density ρ
Air density, ρ
Altitude above sea level
kg/m
m
0 °C 20 °C 40 °C
-1 000 1,44 1,34 1,26
0 1,30 1,21 1,13
1 000 1,16 1,07 1,01
2 000 1,01 0,94 0,88
When air is saturated, such as in an upcast shaft, the density should be increased by 25 %.
6.3 Rope torque
6.3.1 Head rope torque
The rope torque applied to a conveyance, Q, by any one head rope is defined as:
QC= dT (6)
QR H
where
10 © ISO 2021 – All rights reserved

C is the rope torque factor;
Q
d is the rope diameter, m;
R
T is the head rope tension at the conveyance, N.
H
6.3.2 Tail rope torque
The rope torque applied to a conveyance, Q, by any one tail rope shall be determined on the basis of
the method of attachment of the tail rope to the conveyance. Where steel wire ropes are used and the
attachment of the tail rope to the conveyance is fixed, the torque shall be taken as:
QC= dT (7)
QR T
where T is the tail rope tension at the conveyance, N.
T
In other cases, the torque may be neglected.
6.3.3 Torque applied by multiple ropes
The torque applied to a conveyance by multiple head or tail ropes shall be determined on a rational
basis, taking account of the handing of the ropes, the variability of the rope tension, and the variability
of the rope torque factor. The values given in Table 2, based on the method recommended in Annex D,
may be used.
Table 2 — Recommended torque values
Number of head ropes Recommended torque
QC= dT
QR
QC=±03, dT
QR
QC=13, dT
QR
QC=±05, dT
2n
QR
QC=15, dT
2n+1
QR
n is an integer greater than or equal to 2.
6.4 Eccentric conveyance loading
The overturning moment due to eccentric loading of the conveyance payload shall be taken into account.
The overturning moment due to payload eccentricity M is defined as:
O
Mm= x (8)
OP P
where
m is the payload mass, kg;
P
x is the horizontal distance between payload centre of gravity and centre of hoist rope attach-
P
ment, m.
If the payload is persons, or rock in a skip, the eccentric loading may be taken as zero.
If the payload is centred in the conveyance by some means, the eccentric loading may be taken as zero.
6.5 Winder emergency braking
The rope torque and the eccentric conveyance loading actions shall be increased during winder
emergency braking by the dynamic magnification factor for torque and eccentric conveyance loading,
α :
T
2a
α =±1 (9)
T
g
where
a is the braking deceleration, m/s ;
g is gravity acceleration, m/s .
The increased head rope tension T' is defined as:
H
′
TT=α (10)
H T H
where
T is the head rope tension, N;
H
α is the dynamic magnification factor for torque and eccentric conveyance loading.
T
Whether the rope torque and the eccentric conveyance loading actions under winder emergency
braking conditions need to be combined with other actions shall be assessed on a rational basis. Factors
to consider include:
— the number of winders in the shaft;
— how the winders are interlocked;
— direction of conveyance travel and air flow.
6.6 Thermal actions on headframe
Consideration should be given to the possibility of lateral movement of the rope guide anchorages due
to deformation of the headframe due to thermal effects.
6.7 Wind load on conveyances
Where the headframe has open sides, a conveyance in the headgear can be subjected
...