ISO 19426-4:2018

Structures for mine shafts - Part 4: Conveyances

This document specifies the loads, the load combinations and the design procedures for the design of the steel and aluminium alloy structural members of conveyances used for the transport of personnel, materials, equipment and rock in vertical and decline shafts. The conveyances covered by this document include personnel or material cages (or both), skips, kibbles, equipping skeleton cages, inspection cages, bridles, crossheads and counterweights. This document is not intended to be used for the design of ropes, sheaves or attachments. Rope sizes are determined in accordance with other standards. This document does not cover chairlifts. This document does not cover matters of operational safety or layout of conveyances. This document adopts a limit states design philosophy.

Structures de puits de mine — Partie 4: Moyens de transport

General Information

• Status: Published
• Publication Date: 03-May-2018
• ICS: 73.020 - Mining and quarrying
• Technical Committee: ISO/TC 82 - Mining
• Drafting Committee: ISO/TC 82/WG 4 - Structures for mine shafts
• Current Stage: 9092 - International Standard to be revised
• Start Date: 15-Sep-2023
• Completion Date: 13-Dec-2025

Overview

ISO 19426-4:2018 - Structures for mine shafts, Part 4: Conveyances specifies the loads, load combinations and design procedures for the steel and aluminium-alloy structural members of mine-shaft conveyances. It applies to vertical and decline shafts and covers conveyances used to transport personnel, materials, equipment and rock, including personnel/material cages, skips, kibbles, equipping and inspection cages, bridles, crossheads and counterweights. The standard adopts a limit states design philosophy and focuses on structural design; it does not cover ropes, sheaves, rope attachments, chairlifts, operational safety or conveyance layout.

Key Topics and Requirements

• Material guidance: Requirements for steel (including high-strength grades and cold-temperature considerations) and aluminium alloys for structural members.
• Nominal and general operating loads: Definitions of permanent, imposed and lateral loads relevant to shaft conveyances.
• Specific load types:
  • Vertical and lateral loads from guide systems (fixed guide systems and rope-guided systems).
  • Winder-system loads (acceleration/deceleration, trip-out, tail-rope and vertical friction loads).
  • Personnel and seating loads, floor loads for material/equipment, underslung and trailing loads.
  • Rock-winding loads for skips and kibbles (filling, emptying, impact and reference rock pressure).
  • Emergency loads: rope emergency, drop-back, roof impact, emergency stopping and overspeed device loads.
• Design procedures: Methods to derive design loads, application of load combinations, design for emergency loads, fatigue considerations and special provisions for steel versus aluminium components.
• Construction and testing: Fabrication tolerances, confirmation of design through testing (including operating mechanism tests) and construction requirements.

Practical Applications and Users

ISO 19426-4:2018 is essential for professionals involved in the engineering and delivery of mine-shaft conveyances:

• Mining and shaft structural engineers designing cages, skips, kibble structures, crossheads and counterweights.
• Conveyance manufacturers and fabricators responsible for steel or aluminium structural components.
• Design verification and testing teams conducting structural testing and fatigue assessments.
• Standards and compliance officers ensuring designs meet internationally recognized load and design criteria.
• Project managers and contractors planning installation, construction quality and acceptance testing.

Using this standard ensures consistent, repeatable structural design practices for conveyances in vertical and decline shafts, helping reduce structural failure risk and informing safe, code-compliant fabrication.

Related Standards (if applicable)

• Other parts of the ISO 19426 series on mine-shaft structures.
• Standards covering ropes, sheaves and attachments (refer to appropriate rope and winding-equipment standards) and national/regional mining safety regulations for operational practices.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 19426-4
First edition
2018-05
Corrected version
2020-03
Structures for mine shafts —
Part 4:
Conveyances
Structures de puits de mine —
Partie 4: Moyens de transport
Reference number
©
ISO 2018
© ISO 2018
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Fax: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2018 – All rights reserved

Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols . 2
5 Materials . 4
5.1 Steel . 4
5.1.1 High strength steel grades . 4
5.1.2 Cold temperature operation . 4
5.2 Aluminium alloys . 4
6 Nominal operating loads . 4
7 General operating loads . 5
7.1 Permanent loads . 5
7.2 Vertical imposed loads due to holding devices . 5
7.2.1 Holding device engagement load . 5
7.2.2 Holding devices securing load . 5
7.3 Lateral imposed loads . 6
7.3.1 Fixed guide systems in vertical shafts . 6
7.3.2 Rope guide systems . 6
7.3.3 Decline shaft conveyance wheel loads . 6
7.4 Winder system loads. 7
7.4.1 Acceleration/deceleration load . 7
7.4.2 Trip-out load . 7
7.4.3 Tail-rope load . 8
7.4.4 Vertical friction load . 8
7.5 Roof loads . 8
8 Personnel winding loads . 8
8.1 Standing personnel load . 8
8.2 Seated personnel load. 8
8.3 Loading of cages . 8
8.4 Loading of cages in decline shafts . 8
8.5 Dogging system load . 9
9 Material and equipment winding loads . 9
9.1 Floor loads . 9
9.1.1 Static load . 9
9.1.2 Impact loads . . . 9
9.2 Underslung loads or trailing loads .11
10 Rock winding loads .11
10.1 Skip loads .11
10.1.1 General.11
10.1.2 Static rock loads.11
10.1.3 Bridle and top transom loads during filling .12
10.1.4 Reference rock pressure .12
10.1.5 Pressure during filling or travelling in the shaft .12
10.1.6 Pressures during emptying.13
10.1.7 Load on tipping rollers .14
10.1.8 Skip return-stop loads . .14
10.2 Kibble loads .14
10.2.1 Static rock or slurry loads .14
10.2.2 Reference rock or slurry pressure .14
10.2.3 Pressure during filling . .15
10.2.4 Pressures during emptying.15
10.2.5 Heavy kibble payloads .15
11 Emergency loads .15
11.1 Rope emergency load .15
11.1.1 Permanent operating conveyances with fixed rope winders .15
11.1.2 Permanent operating conveyances with friction winders .15
11.1.3 Temporary equipping, maintenance and inspection conveyances .16
11.1.4 Slung equipment and conveyances .16
11.1.5 Kibbles and kibble cross-heads .16
11.2 Emergency drop-back loads .16
11.2.1 General.16
11.2.2 All permanent conveyances.16
11.2.3 Kibbles and kibble cross-heads .17
11.3 Roof impact loads .17
11.4 Skip loads .17
11.4.1 General.17
11.4.2 Reference rock pressure .17
11.4.3 Pressure during filling or travelling in the shaft .17
11.5 Emergency stopping device loads .18
11.5.1 Overspeed device .18
11.6 Application of emergency loads .19
12 Design procedures .19
12.1 Design loads .19
12.2 Design codes .19
12.3 Design for emergency loads .19
12.3.1 Steel components .19
12.3.2 Aluminium components .19
12.3.3 Special considerations .19
12.4 Fatigue .19
13 Construction requirements .20
13.1 General .20
13.2 Confirmation of design by testing .20
13.2.1 Testing of operating mechanisms .20
13.3 Construction tolerances .20
Annex A (informative) Load factors and load combinations .22
Annex B (informative) Examples of tipping roller and skip return-stop loads .24
Bibliography .28
iv © ISO 2018 – 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.
This corrected version of ISO 19426-4:2018 incorporates the following correction:
— in 11.4.3.3, a), paragraph below Formula (33), the wording and value have been corrected to read
"but the rock size shall not be taken as less than 0,02 m .".
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 which 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. It is also recognised that typical equipment
varies from country to country, so the clauses in ISO 19426 do not specify application of the principles
to specific equipment. However, in some cases examples demonstrating the application of the principles
to specific equipment are provided in informative Annexes.
vi © ISO 2018 – All rights reserved

INTERNATIONAL STANDARD ISO 19426-4:2018(E)
Structures for mine shafts —
Part 4:
Conveyances
1 Scope
This document specifies the loads, the load combinations and the design procedures for the design of
the steel and aluminium alloy structural members of conveyances used for the transport of personnel,
materials, equipment and rock in vertical and decline shafts. The conveyances covered by this document
include personnel or material cages (or both), skips, kibbles, equipping skeleton cages, inspection cages,
bridles, crossheads and counterweights.
This document is not intended to be used for the design of ropes, sheaves or attachments. Rope sizes
are determined in accordance with other standards.
This document does not cover chairlifts.
This document does not cover matters of operational safety or layout of conveyances.
This document adopts a limit states design philosophy.
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 2394, General principles on reliability for structures
ISO 10721-1, Steel structures — Part 1: Materials and design
ISO 10721-2, Steel structures — Part 2: Fabrication and erection
ISO 19426-1, Structures for mine shafts — Part 1: Vocabulary
ISO 19426-2, Structures for mine shafts — Part 2: Headgear structures
ISO 19426-5, Structures for mine shafts — Part 5: Shaft system structures
ISO 22111, Bases for design of structures — General requirements
EN 1999-1-1, Eurocode 9 — Part 1: Design of aluminium structures — Part 1: General structural rules
EN 1999-1-3, Eurocode 9 — Part 1: Design of aluminium structures — Part 3: Structures susceptible to fatigue
EN 1999-1-4, Eurocode 9 — Par 1: Design of aluminium structures — Part 4: Cold-formed structural
sheeting
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 19426-1 apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at http:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org
4 Symbols
A operating winder system acceleration/deceleration load (N)
o
A trip-out winder deceleration load (N)
t
maximum permitted deceleration of the conveyance when the dogging system acti-
a
D 2
vates (m/s )
a operating winder system peak acceleration/deceleration (m/s )
o
a trip-out winder system peak deceleration (m/s )
t
C impact load during loading of the conveyance (N)
C horizontal impact load from rolling stock (N)
h
C vertical impact load from rolling stock (N)
v
C conveyed load (P, ΣM, U or R, as appropriate) (N)
y
D dogging system load (N)
d deformation of the skip door (m)
i
E emergency dropback load (N)
j
E rope emergency load (N)
r
maximum moving beam misalignment of the guide (m); lateral flare dimension (see
e
Figure 1)
F design load, or load effect (N, Nm)
F friction induced vertical load (N)
v
are the permanent loads, including the self-weight of the structure and the structural
G and G
1 2
components, in newtons (N)
G conveyance self-weight load (N)
c
g acceleration due to gravity (m/s )
H lateral imposed load (N)
H rubbing block load (N)
r
H lateral slipper plate load (N)
s
h length through which the rock falls (m)
d
h height to which the skip is filled above the lowest point of the skip door (m)
h
K station-mounted holding device engagement load (N)
2 © ISO 2018 – All rights reserved

K conveyance-mounted holding device load (N)
c
K lateral stiffness of the steelwork at the guide mid-span or at the end of the flare (N/m)
g
K buffer spring stiffness (N/m)
s
L guide span, bunton to bunton or the length of the flare guide (m)
L distance between the pivot and the centre of gravity of the skip, or the radial door (m)
L distance between the pivot and the return-stop (or the tipping roller) (m)
L length of the crawler track (m)
T
M load from each item of rolling stock or equipment (N)
M heavier axle load (N)
m conveyance mass including all attachments, excluding rope attachments (kg)
c
m mass of largest rock that will be loaded into the skip (kg)
r
P load from personnel (N)
p to p skip pressures (N/m )
o 3
Q dominant imposed load or load effect (N, Nm)
Q to Q are the additional independent imposed loads, or load effects (N, Nm)
2 n
Q emergency load or load effect (N, Nm)
e
R static rock or slurry load (N)
R bridle and top transom load during filling (N)
d
R friction load on the skip door (N)
f
R single rock impact vertical load on the skip door (N)
i
R single rock impact horizontal load on the skip sides (N)
k
R load on skip return-stops (N)
s
R load on tipping rollers (N)
t
T load due to the tail rope (N)
U load due to underslung equipment (N)
z maximum depth of rock or slurry contained in the conveyance (m)
Z impact energy of the falling rock (J)
i
α dynamic impact factor
d
α horizontal load impact factor
h
α holding device impact factor
k
α rock impact factor
p
α tipping impact factor.
t
α vertical load impact factor
v
β rope emergency factor
γ partial load factor for emergency loads.
e
γ partial load factor for imposed loads
fi
γ and γ partial load factors for permanent loads
g1 g2
γ to γ partial load factors for imposed loads
f1 fn
γ partial load factor for permanent loads
gi
μ friction factor between the skip payload and the door
ρ bulk density of rock (kg/m )
Ψ to Ψ load combination factors
2 n
5 Materials
5.1 Steel
The materials used for structural steel members should comply with the requirements of EN 10025-1
and EN 10025-2.
5.1.1 High strength steel grades
The materials for high strength steel members should conform to the requirements of EN 10025-6,
EN 10149-1, EN 10149-2, or EN 10149-3.
5.1.2 Cold temperature operation
Where necessary due to possible brittle fracture in cold operating temperatures, bridles, top transom
and bottom transom members and fall back arrestors and their supports should have a minimum
Charpy V-notch impact value of 27 J at 0 °C.
5.2 Aluminium alloys
The materials used for aluminium alloy members should comply with:
a) for extrusions: the requirements of EN 515, EN 573-3, EN 755-1, EN 755-2, EN 755-3, EN 755-4,
EN 755-5, EN 755-7, or EN 12020-1 and EN 12020-2;
b) for rolled products: the requirements of EN 485-1, EN 485-2, EN 485-3 or EN 485-4 or IEC 60079.
In addition, extrusions and rolled products used for the fabrication of bridles and top transom and
bottom transom members should be individually identified and should be the subject of quality systems.
6 Nominal operating loads
The nominal operating loads shall be as given in Clauses 7 to 10. The nominal emergency load shall be
as given in Clause 11.
4 © ISO 2018 – All rights reserved

7 General operating loads
7.1 Permanent loads
Permanent loads shall be as defined in ISO 22111.
The permanent load, G , shall be taken as the total self-weight of the conveyance structure and all
c
attachments, excluding rope attachments. The permanent load, G (N) shall be calculated using the
c ,
following Formula:
G = g m (1)
c c
where
g is the acceleration due to gravity (m/s );
m is the conveyance mass including all attachments, excluding rope attachments (kg).
c
7.2 Vertical imposed loads due to holding devices
7.2.1 Holding device engagement load
The holding device engagement load, K (N), shall be calculated using the following Formula:
KG=+α CT+ (2)
()
kc y
where
α is the holding device impact factor, which may be taken as 1,5 in the absence of better infor-
k
mation, and provided the conveyance is not travelling at more than creep speed (0,5 m/s)
when the devices are engaged;
C equals P, ∑M, U or R, as appropriate (N);
y
T is the load due to the tail rope or ropes (N).
NOTE Some holding devices are only applied after the conveyance has stopped completely. In this case the
load specified here does not apply.
7.2.2 Holding devices securing load
The holding device securing load, K (N), shall be calculated using the following Formula:
c
K = α C (3)
c k y
where
α is the holding device impact factor, which in the absence of better information may be taken as:
k
1,0 for personnel loading;
2,0 for materials loading;
1,5 for rock loading;
C equals P, ∑M, U or R, as appropriate (N).
y
7.3 Lateral imposed loads
7.3.1 Fixed guide systems in vertical shafts
The lateral loads imposed on conveyances running on fixed guide systems in vertical shafts shall be
taken as equal to the lateral loads imposed on shaft steelwork, as defined in ISO 19426-5.
7.3.2 Rope guide systems
7.3.2.1 Only one of the loads given in 7.3.2.2 to 7.3.2.4 shall be engaged at any one time.
7.3.2.2 Whilst running in rope guides, the rubbing block load, H , may, in the absence of better
r
information, be taken as:
H = 0,01 (G + C) (4)
r c y
This load may be distributed amongst all the rubbing blocks.
7.3.2.3 While entering the fixed flare guides or spear guides near stations, the slipper plate load,
H , shall be calculated in accordance with ISO 19426-5, for fixed guide systems, but with the following
s
modifications:
L is the length of the flare (see Figure 1) (m);
e is the lateral flare guide or spear guide dimension (see Figure 1), unless a rational analysis
shows otherwise (m);
K is the steelwork stiffness at the end of the flare (N/m).
g
7.3.2.4 While running in fixed guides at stations, the slipper plate load, H , shall be as defined in
s
ISO 19426-5, for fixed guide systems.
7.3.3 Decline shaft conveyance wheel loads
The loads imposed on conveyances in the direction normal to the rail and transverse to the rail in
decline shafts shall be taken as equal to the loads imposed on shaft rails in decline shafts, as defined in
ISO 19426-5.
6 © ISO 2018 – All rights reserved

Figure 1 — Typical flare guide or spear guide arrangement
7.4 Winder system loads
7.4.1 Acceleration/deceleration load
The load, A (N), due to the operating acceleration or deceleration of the winder system shall be taken as
o
α a
do
A =+GC +T (5)
()
o cy
g
where
α is the dynamic impact factor, which may be taken as 2,0, in the absence of better information;
d
a is the operating winder system peak acceleration/deceleration (m/s );
o
g is the acceleration due to gravity (m/s );
G is the conveyance self-weight load (N);
c
C equals P, ∑M, U or R, as appropriate (N);
y
T is the load due to the tail rope (N).
7.4.2 Trip-out load
The load A (N), due to deceleration of the winder system during a trip-out shall be taken as:
t
α a
dt
A =+GC +T (6)
()
t cy
g
where a is the trip-out winder system peak deceleration (m/s ).
t
7.4.3 Tail-rope load
For friction winder systems, the load, T (due to the tail ropes), shall be determined from the winder
system design requirements. Both maximum and minimum tail-rope loads shall be considered.
7.4.4 Vertical friction load
The vertical load, F (N), induced by friction during slipper plate contact on each guide, shall be taken as:
v
F = 0,5 H (7)
v s
where H is the lateral slipper plate load (N).
s
7.5 Roof loads
The roof of cages shall be subjected to one of the following:
a) cages in vertical shafts with a uniformly distributed vertical load of 3 000 N/m ; or
b) cages in decline shafts with a uniformly distributed vertical load of 1 500 N/m .
8 Personnel winding loads
8.1 Standing personnel load
The load for standing personnel shall be taken as
a) a vertical load, P, of 5 000 N/m , acting on the horizontal deck area, and
b) horizontal line load, H, along the sides and doors of the conveyance, of 2 000 N/m. This load shall be
applied 1,5 m above the floor, acting outwards.
8.2 Seated personnel load
The load, P, for seated personnel, shall be taken as 4 000 N/m of horizontal projected deck area.
8.3 Loading of cages
Overturning or tilting of cages during loading shall be checked by applying the loads given in 8.1 and
8.2 to any unfavourable half of the floor area of the cage.
8.4 Loading of cages in decline shafts
Where personnel enter from the side of cages in decline shafts, the following loads, P, shall be applied at
the roof level above the entry points:
a) a horizontal concentrated load of 1 000 N acting in the direction of entry into the cage shall be
applied simultaneously at each entry point;
b) a vertical load of 2 000 N shall be applied simultaneously at each entry point.
8 © ISO 2018 – All rights reserved

8.5 Dogging system load
Where a dogging system is used, the dogging system load, D (N), shall be taken as:
 a 
D
D=+1 GC+ (8)
()
  cy
g
 
where
a is the maximum permitted conveyance deceleration when the dogging system activates (m/
D
2 2
s ), which may be taken as 19,6 m/s in the absence of better information;
g is gravity acceleration (m/s );
G is the conveyance self-weight load (N);
c
C is P, ∑M, U or R, as appropriate (N);
y
This load shall be rationally distributed to the elements of the dogging system.
9 Material and equipment winding loads
9.1 Floor loads
9.1.1 Static load
The load, M, for each item of rolling stock or equipment shall be determined for the particular
application.
9.1.2 Impact loads
9.1.2.1 Rolling stock load
Impact loads during loading and off-loading shall be determined using the following Formulas.
a) For the vertical axle load, C (N):
v
C = α M (9)
v v 1
where
α is the vertical load impact factor, which may be taken as given in Table 1;
v
M is the heavier axle load (N).
Table 1 — Recommended values of α , the vertical load impact factor
v
Rubber-tyred Crawler-mounted
Context Rolling stock
vehicle vehicle
The conveyance in a vertical shaft is held in position
2,0 1,2 2,0
during loading
The conveyance is on rails in a decline shaft 2,0 1,2 2,0
The conveyance in a vertical shaft is not held in posi-
3,5 2,0 3,5
tion during loading
b) For the horizontal load, C (N):
h
CM=α (10)
hh
If a buffer with spring stiffness, K , is used, then α may be calculated using the following Formula:
s h
gK
s
α =05, but not > than 0,5 (11)
h
M
In all other cases, α = 0,5.
h
9.1.2.2 Rubber-tyred, self-propelled vehicle load
Impact loads during loading and off-loading shall be determined using the following Formulas.
a) For the vertical axle load, C (N):
v
C = α M (12)
v v 1
where
α is the vertical load impact factor, which may be taken as given in Table 1.
v
M is the heavier axle load (N).
b) For the horizontal load, C (N):
h
1) The total horizontal braking load on the floor of the conveyance shall be taken as:
C = α M (13)
h h
where α is a braking or acceleration impact load, which may be taken as 0,1 in the absence of
h
better information.
2) The horizontal impact load on the back wall of the conveyance shall be taken as:
C = α M
h h
where α is the horizontal load impact factor, which may be taken as 0,2 in the absence of better
h
information.
9.1.2.3 Crawler-mounted, self-propelled vehicle load
Impact loads during loading and off-loading shall be determined using the following Formulas.
a) For the vertical load, C (N):
v
The vertical load shall be taken as the most severe of the following:
1) concentrated loads at the front end and the rear end of each track, with a magnitude of:
α M
v
C = (14)
v
2) concentrated loads at the centre of each track, with a magnitude of:
α M
v
C = (15)
v
10 © ISO 2018 – All rights reserved

3) uniformly distributed loads along the full length of each track, with a magnitude of:
α M
v
C = (16)
v
2L
T
where
α is the vertical load impact factor, and may be taken as given in Table 1;
v
L is the length of the crawler track (m).
T
b) For the horizontal load, C (N):
h
1) The total horizontal braking load on the floor of the conveyance shall be taken as:
C = α M (17)
h h
where α is a braking or acceleration impact load, which may be taken as 0,1, in the absence of
h
better information.
2) The horizontal impact load on the back of the conveyance shall be taken as:
C = α M (18)
h h
where α is the horizontal load impact factor, which may be taken as 0,2, in the absence of
h
better information.
9.1.2.4 Other material and equipment loads
Impact loads shall be determined for the particular circumstances, cognizance being taken of the
method of loading.
9.2 Underslung loads or trailing loads
The load, U, due to under slinging in vertical shafts or trailing loads in decline shafts, shall be determined
for the particular application in vertical or decline shafts. Consideration shall be given to vertical and
induced horizontal loads during loading and off-loading.
10 Rock winding loads
10.1 Skip loads
10.1.1 General
The rock pressures and loads used for the design of a skip are dependent on factors such as its shape,
the method of loading, rock properties, the type of liner used, the presence or otherwise of skip holding
devices, and rope elasticity. In the absence of better information the pressures and loads given in 10.1.2
to 10.1.8 may be used.
10.1.2 Static rock loads
The static rock load, R, shall be based on the maximum capacity of the skip without a surcharge.
10.1.3 Bridle and top transom loads during filling
The bridle and top transom load during filling, R (N), shall be taken as:
d
R = α R (19)
d v
where
α is the vertical load impact factor, which may be taken as 1,1 when the conveyance is held in
v
position during loading;
α is the vertical load impact factor, which may be taken as 1,5 when the conveyance is not held
v
in position during loading;
10.1.4 Reference rock pressure
The reference rock pressure, p (N/m ), for the design of skips shall be taken as:
o
p = ρ g z (20)
o
where
ρ is the bulk density of rock, (kg/m );
g is the acceleration due to gravity (m/s );
z is the maximum depth of rock contained in the conveyance (m).
10.1.5 Pressure during filling or travelling in the shaft
10.1.5.1 Pressure on skip bottom (p )
The pressure on the skip bottom, p (N/m ), during filling or during travelling in the shaft shall be
taken as:
p = α p (21)
1 p o
where
α is the rock pressure factor, which may be taken as given in Table 2 (see Figure 2);
p
12 © ISO 2018 – All rights reserved

Table 2 — Recommended values of α , the rock pressure factor
p
Context Filling skip Travelling in shaft Emptying skip
Skip bottom or door surface 1,0 1,0 1,0
Skip side surface inclined at more than
60° to horizontal and on which rock 0,5 0,3 0,3
impacts during filling
Skip side surface inclined at not more
than 60° to horizontal and on which 1,0 0,3 0,3
rock impacts during filling
Skip side surface on which rock does
0,3 0,3 0,3
not impact during filling
Skip door or side surface within 0,3 m
above and below of any location at
— — 1,5
which the rock flow direction is forced
to change during emptying of the skip
10.1.5.2 Side pressure (p )
10.1.5.2.1 The side pressure, p (N/m ), on the skip sides during filling or during travelling in the shaft
shall be taken as:
p = α p (22)
2 p o
where
α is the rock pressure factor (see Figure 2).
p
10.1.5.2.2 In the absence of better information, the rock pressure factor, α , may be taken as given in
p
Table 2.
10.1.6 Pressures during emptying
The side or bottom pressure, p (N/m ), shall be taken as:
p = α p (23)
3 p o
where
α is the rock pressure factor which may be taken as 1,5 for an area based on a distance of 0,3 m
p
above and below the intersection of the skip body and the discharge chute, or any other loca-
tion at which the rock flow is forced to change direction (see Figure 2);
it may be taken as 0,3 for all other surfaces (see Figure 2).

(a) Filling (b) Emptying
Figure 2 — Typical rock impact factors (α )
p
10.1.7 Load on tipping rollers
The tipping roller loads shall be determined on a rational basis, depending on the skip tipping
mechanism. Annex B gives specific examples.
10.1.8 Skip return-stop loads
The skip return-stop loads shall be determined on a rational basis, depending on the skip tipping and
return mechanism. Annex B gives specific examples.
10.2 Kibble loads
10.2.1 Static rock or slurry loads
The static rock or slurry load, R, shall be based on the maximum capacity of the kibble, including the
surcharge.
10.2.2 Reference rock or slurry pressure
The reference rock or slurry pressure, p (N/m ), for the design of kibbles, shall be taken as:
o
p = ρ g z (24)
o
where
14 © ISO 2018 – All rights reserved

ρ is the higher of the saturated rock density or the slurry density of the rock (kg/m );
g is the acceleration due to gravity (m/s );
z is the maximum depth of rock contained in the conveyance (m).
10.2.3 Pressure during filling
10.2.3.1 Pressure on kibble bottom (p )
The pressure on the kibble bottom, p (N/m ), shall be taken as:
p = α p (25)
1 p o
where
α = 1,0.
p
10.2.3.2 Side pressure (p )
The side pressure, p (N/m ), shall be taken as:
p = α p (26)
2 p o
where
α = 0,3, in the case of rock;
p
= 1,0, in the case of slurry.
10.2.4 Pressures during emptying
Pressures during emptying are deemed to be not greater than those during filling. However, cognizance
shall be taken of the re-orientation of the kibble and its loads during emptying.
10.2.5 Heavy kibble payloads
Where specific heavy equipment is transported in the kibble, cognizance shall be taken of this in the
design of the kibble.
11 Emergency loads
11.1 Rope emergency load
11.1.1 Permanent operating conveyances with fixed rope winders
The rope emergency load, E , shall be taken as the actual rope breaking load. In the absence of this
r
information, the rope emergency load, E , may be taken as 1,1 times the estimated rope breaking load.
r
11.1.2 Permanent operating conveyances with friction winders
The rope emergency load, E , shall be assessed by a rational analysis. As an upper limit the rope load
r
given in 11.1.1 may be used as defin
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