ISO 19426-3:2026

• Abstract:

  This document specifies the design loads and the design procedures for the structural design of stages and components of stages. The loads specified in this document are not applicable for the design of stage ropes or sheaves. Rope sizes are determined in accordance with other standards. This document does not cover matters of operational safety, or layout of the sinking stage and other mechanised methods of shaft sinking that shall be addressed using a rational method. This document adopts a limit states design philosophy.

• Status: Published
• Publication Date: 14-Sep-2026
• 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: 6060 - International Standard published
• Start Date: 15-Sep-2026
• Due Date: 15-Sep-2026
• Completion Date: 15-Sep-2026

• Revises: ISO 19426-3:2018 - Structures for mine shafts — Part 3: Sinking stages
• Effective Date: 16-Sep-2023

ISO 19426-3:2026 is an International Standard published by ISO for the structural design of sinking stages used in mine shafts. It specifies the design loads and design procedures for stages and stage components, using a limit states design philosophy, for engineers and others responsible for designing, checking or specifying shaft-sinking structures.

What does ISO 19426-3:2026 specify?

ISO 19426-3:2026 sets the loading basis and design approach for the structural design of sinking stages and their components. It focuses on stage structure design, while limiting how the standard is applied to ropes, sheaves, operational safety and mechanised shaft sinking methods.

The document is organized into clauses on scope, references, terms, symbols, materials, nominal loads and design procedures, followed by informative annexes with load combinations and examples.

Annex	What it covers
Annex A	Load factors and load combinations for operating and emergency conditions
Annex B	Examples of jumbo unit loads
Annex C	Examples of lashing unit loads
Annex D	Examples of stage jack loads with lashing

The scope is important in practice because it tells the reader where this standard applies directly and where another method or another standard is needed. Rope sizes, for example, are determined elsewhere, and layout or mechanised sinking methods are to be addressed using a rational method.

What are the key requirements of ISO 19426-3:2026?

ISO 19426-3:2026 ties together material selection, load definition and structural verification. The most important point for users is that the standard does not give one universal stage design - it gives the load cases and design checks that must be matched to the actual stage, equipment and operating situation.

Materials and design basis

Clause 5 limits the material choices for structural steel, high strength steel and aluminium alloy members to cited product standards. In practice, this means the designer and purchaser need to align the chosen material form with the referenced steel or aluminium standard before final design and fabrication.

Clause 7 says that design loads for operating and emergency conditions come from Clause 6 and are combined using reliability principles from ISO 2394 and ISO 22111. This matters because the standard expects the designer to use load factors and combinations, not just nominal loads on their own.

Nominal load cases

Clause 6.1 defines the permanent load, G, as the stage plus the permanent fixtures and equipment needed for shaft sinking and lining. That is the baseline load that is always present.

Clause 6.2 sets the imposed load cases for the main stage functions, including deck loading, shaft formwork winching, kibble cross-head support, jumbo unit operation, lashing unit operation, stage jacking, skids, canopy, kibble guides, temporary supports, blast, guard railing and special loads. For a design review, this is the section that tells you which activities and pieces of equipment have to be checked.

Several of these loads are based on the actual geometry and operating position of the equipment. That is important because the worst case may come from boom position, lever arm, eccentric placement or the way loads are shared across support points rather than from weight alone.

Emergency and exceptional conditions

Clause 6.3 adds emergency rope load and emergency impact load cases. These are the checks that protect critical components against rare but severe events, especially at the top deck and on members that would see high short-duration actions.

Clause 6.2.10 also allows temporary stage support load to include load reversal during erection or maintenance. That tells the designer to consider non-routine handling states, not only normal sinking operations.

Design checks and limits

Clause 7.3 requires load reversal to be considered where a stage may be assembled, lowered or otherwise handled in a way that reverses the loading direction on main members. This is a practical issue for temporary states and can govern member sizing.

Clause 7.4 allows selected non-critical members to be designated as replaceable, with a limited overload margin if they are ductile. This is useful where a damaged part can be changed rather than treated as a non-repairable failure.

Clause 7.5 limits top deck beam deflection under specified impact energy, and Clause 7.6 limits deck and floor beam deflection to L/200, with a special treatment for cantilevers. Clause 7.7 requires stage stability to be considered against equipment placement, deck layout and rope attachment location. Together, these clauses show that serviceability and stability are part of the design, not just strength.

What terms does ISO 19426-3:2026 define?

The document uses the vocabulary of ISO 19426-1, and Clause 4 lists the symbols used throughout the calculations.

• Permanent load, G - the load that remains on the stage, including permanent fixtures and equipment.
• Imposed load, P - a working load applied by an operation, piece of equipment or stage use case.
• Emergency load, E - a load effect used for rare emergency conditions such as rope failure or impact.
• Design load, F - the combined load effect used for structural verification after factors and combinations are applied.
• Stage load eccentricity factor, e - a factor used to account for uneven loading or eccentric loading on the stage skids.
• Swell factor, s_f - a factor used in lashing unit cycle estimation to reflect the relationship between excavated volume and loose rock volume.
• Efficiency or fill factor, η - a factor used in the lashing cycle calculation to reflect how fully the grab is filled.

Who uses ISO 19426-3:2026?

ISO 19426-3:2026 is used by mining companies, mining engineering firms and structural designers working on mine shaft sinking stages. It is also relevant to equipment suppliers, detail designers and checking engineers who need to define load cases for jumbo units, lashing units, stage jacks and related stage hardware.

In practice, users apply it when they are sizing stage members, checking load combinations, selecting material standards, or reviewing whether a proposed stage arrangement fits the intended sinking method. Clients, quality managers and buyers can also use it to compare offers against the same technical basis.

What changed in ISO 19426-3:2026 from the previous edition?

ISO 19426-3:2026 is the second edition and cancels and replaces ISO 19426-3:2018.

The changes stated in the foreword are:

• stability consideration was added to the design procedure;
• the definition of swell factor was added and the lashing unit load equation was updated to allow different swell factors;
• dewatering equipment was added to special loads;
• the scope was changed to exclude mechanised shaft sinking methods.

Which standards are used with ISO 19426-3:2026?

ISO 19426-3:2026 relies on several referenced standards for reliability, execution, design methods and materials.

• ISO 2394 - general principles on reliability for structures.
• ISO 17607 (all parts) - execution requirements for steel structural work.
• ISO 19426-1 - vocabulary for structures for mine shafts.
• ISO 22111 - general requirements for bases for design of structures and the load-factor framework used with this part.
• EN 1999-1-1, EN 1999-1-3 and EN 1999-1-4 - design rules for aluminium members, fatigue-sensitive parts and cold-formed sheeting.
• CEN/TS 13001-3-1 - limit states and proof competence rules for high strength steel members.
• EN 10025-1, EN 10025-2, EN 10025-6, EN 10149-1, EN 10149-2 and EN 10149-3 - material standards for the steel members used in stage structures.
• EN 573-3, EN 485-1 to EN 485-4 and EN 755-1 to EN 755-9 - material and product standards for aluminium alloy members.

What does the ISO 19426-3:2026 document contain?

ISO 19426-3:2026 contains the symbol list, material clauses, load definitions and structural design procedures for sinking stages. It also contains the load combinations and partial factors used to move from nominal loads to design loads.

Annex A gives the load factor framework for operating and emergency conditions. Annexes B, C and D provide worked examples and load distributions for jumbo units, lashing units and stage jacks, which helps users apply the clauses to real equipment layouts. Figures in the annexes show how those loads act on the stage structure, and the bibliography lists related aluminium and steel material standards and one mining design commentary.

International
Standard
ISO 19426-3
Second edition
Structures for mine shafts —
2026-09
Part 3:
Sinking stages
Structures de puits de mine —
Partie 3: Plates-formes de fonçage
Reference number
© ISO 2026
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]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword .iv
Introduction .v
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 Structural steel grades .4
5.1.2 High strength steel grades .4
5.2 Aluminium alloys .4
6 Nominal loads . . 4
6.1 Permanent load .4
6.2 Imposed loads.4
6.2.1 Stage deck load .4
6.2.2 Shaft formwork winch load .5
6.2.3 Kibble cross-head support load .5
6.2.4 Jumbo unit load .5
6.2.5 Lashing unit load .6
6.2.6 Stage jack load .6
6.2.7 Stage skid load .6
6.2.8 Canopy load .6
6.2.9 Kibble guide load .7
6.2.10 Temporary stage support load .7
6.2.11 Blast load .7
6.2.12 Guard railing load .7
6.2.13 Special load .7
6.3 Emergency load .8
6.3.1 Emergency rope load .8
6.3.2 Emergency impact load .8
7 Design procedures . 8
7.1 Design loads .8
7.2 Design codes .8
7.3 Load reversal.8
7.4 Design of replaceable members .8
7.5 Impact energy design of top deck .9
7.6 Deflection limitations .9
7.7 Stability consideration .9
Annex A (informative) Load factors and load combinations .10
Annex B (informative) Examples of jumbo unit loads .12
Annex C (informative) Examples of lashing unit loads .15
Annex D (informative) Examples of stage jack loads with lashing .20
Bibliography .24

iii
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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
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.
This second edition cancels and replaces the first edition (ISO 19426-3:2018), which has been technically
revised.
The main changes are as follows:
— stability consideration on the design procedure;
— additional definition of swell factor and lashing unit load equation updated to allow for different swell
factors;
— addition of dewatering equipment to special loads;
— the scope of the document excludes mechanised shaft sinking methods.
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.

iv
Introduction
Many mining companies, and many of the engineering companies which provide designs for mines, operate
globally so ISO 19426 series 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 series will facilitate improved
safety and operational reliability.
The majority of the material in ISO 19426 series 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 recognized that typical equipment varies from
country to country, so the clauses in ISO 19426 series 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.

v
International Standard ISO 19426-3:2026(en)
Structures for mine shafts —
Part 3:
Sinking stages
1 Scope
This document specifies the design loads and the design procedures for the structural design of stages and
components of stages.
The loads specified in this document are not applicable for the design of stage ropes or sheaves. Rope sizes
are determined in accordance with other standards.
This document does not cover matters of operational safety, or layout of the sinking stage and other
mechanised methods of shaft sinking that shall be addressed using a rational method.
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 17607 (all parts), Steel structures — Execution of structural steelwork
ISO 19426-1, Structures for mine shafts — Part 1: Vocabulary
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
CEN/TS 13001-3-1, Cranes — General design — Part 3-1: Limit states and proof competence of steel structures
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 19426-1 apply.
ISO and IEC maintain terminology 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

4 Symbols
C lashing unit grab capacity (m )
E emergency load, or load effect (N, Nm)
e stage load eccentricity factor
G
E emergency impact load (N)
a
E emergency impact load on a protective platform (N)
p
E emergency rope load (N)
R
F design load, or load effect (N, Nm)
G permanent load, or load effect (N, Nm)
G jumbo unit self-weight (N)
D
G lashing unit self-weight (N)
L
K weight of the kibble and full load (N)
L span of an element or floor beam (m)
L lashing unit lever arm or the VSM lashing unit grab lever arm (m)
L stage jack lever arm horizontal (m)
L stage jack lever arm vertical (m)
L jumbo unit centre of gravity lever arm or the VSM lashing unit centre of gravity lever arm (m)
L hydraulic cylinder horizontal lever arm to the boom pivot point (m)
5i
L hydraulic cylinder vertical lever arm to the boom pivot point (m)
6i
M jumbo unit moment about the boom pivot point (Nm)
D
M lashing unit moment about the boom pivot point (Nm)
L
N total number of lashing unit cycles
L
P payload used during doubling-down (N)
p uniformly distributed load on stage decks (N/m )
D
P canopy load (N)
A
P blast load (N)
B
P concentrated load on stage decks (N)
C
P total uniformly distributed imposed load on stage decks (N)
D
P stage skid load (N)
G
P kibble cross-head support load (N)
H
P stage jack load (N)
J
P stage jack axial load (N)
JA
P stage jack transverse load (N)
JT
P kibble guide load (N)
K
P jumbo unit horizontal load (N)
DH
P jumbo unit vertical load (N)
DV
P horizontal lashing unit load (N)
LH
P vertical lashing unit load (N)
LV
P special load (N)
P
P hand railing load (N/m)
R
P temporary stage support load (N)
T
P winch load (N)
W
Q predominant imposed load, or load effect (N, Nm)
Q to Q additional independent imposed loads, or load effects (N, Nm)
3 n
s Swell factor
f
V excavated volume of the shaft (m )
E
W weight of the kibble cross-head (N)
C
W horizontal hydraulic cylinder loads at maximum capacity (N)
CHi
W vertical hydraulic cylinder load (N)
CVi
W weight of the cactus grab including the grab crosshead (N)
G
W weight of rock in the lashing unit grab (N)
PL
W jumbo drilling load (N)
DL
W weight of kibble and full load (N)
K
W rated shutter winch load (N)
R
W weight of the shutter (N)
S
W grab winch safe working load (N)
W
α bellmouth impact factor
B
α impact factor for kibble cross-head support
C
α jumbo unit impact factor
D
α impact factor for emergency rope load
E
α hydraulic cylinder impact factor
H
α kibble guide impact factor
K
α lashing unit impact factor
L
α impact factor for stage jack load
J
α winch rated load impact factor
R
α formwork weight impact factor
S
α stage support impact factor
T
η efficiency or fill factor
γ partial load factor for emergency load
e
γ partial load factor for permanent load
fo
γ partial load factor for the predominant imposed load
f1
γ to γ partial load factors for imposed load
f2 fn
Ψ to Ψ load combination factors
2 n
5 Materials
5.1 Steel
5.1.1 Structural steel grades
The materials used for structural steel members should comply with the requirements of EN 10025-1 and
EN 10025-2.
5.1.2 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.
5.2 Aluminium alloys
The materials used for aluminium alloy members should conform to the requirements of EN 573-3, EN 485-1
to EN 485-4 and EN 755-1 to EN 755-9.
NOTE The preferred alloys include 5083 H32 for 4 mm, 6 mm and 8 mm thick plates or 6082 T651 or 6061 T651
for 10 mm, 12 mm and 15 mm thick plates and 6061 T6 or 6082 T6 for extrusions.
6 Nominal loads
6.1 Permanent load
The permanent load, G, shall be as given in ISO 22111 and shall include the stage and all permanent fixtures
and equipment necessary for the sinking and lining of the shaft.
6.2 Imposed loads
6.2.1 Stage deck load
The imposed load, P or P , on stage decks shall be the most adverse of the following:
D C
a) loads determined by rational method based on the intended use;

b) a uniformly distributed load, P , of 3 000 N/m , which shall be taken to include concrete build-up loads,
D
unless it can be demonstrated that there will be no build-up of concrete in which case take a uniformly
distributed load, P , of 1 500 N/m . P is the total uniformly distributed load on stage decks which shall
D D
be calculated from the uniformly distributed load multiplied by the entire stage deck area;
c) a concentrated load, P , of 5 000 N, placed in the position that produces the most severe effects in the
C
member under consideration.
No area reduction factors shall be included when deck loads from one or more decks are being combined.
Due allowance shall be made for possible eccentric application of stage deck loads. Unless it can be shown
that procedures are in place to ensure concentric placement of all deck loads, it shall be assumed that one
half of each stage deck carries a load of 0,75 P , whilst the other half of the deck carries a load of 0,25 P .
D D
6.2.2 Shaft formwork winch load
The shaft formwork winch load, P (N), shall be the greater of Formulae (1) and (2):
W
P = α W (1)
W S S
P = α W (2)
W R R
where
W is the weight of the shaft formwork (N);
S
W is the rated shaft formwork winch load (N);
R
α is the formwork weight impact factor, which may be taken as 2,0;
S
α is the winch rated load impact factor, which may be taken as 1,5.
R
The shaft formwork winch load shall be appropriately distributed between the winches assuming that any
one winch can fail.
6.2.3 Kibble cross-head support load
The kibble cross-head support load, P (N), shall be obtained from the following Formula (3):
H
P = α W (3)
H C C
where
α is the impact factor for the kibble cross-head support, which if no better information is available
C
may be taken as 2,0;
W is the weight of the kibble cross-head (N).
C
6.2.4 Jumbo unit load
The jumbo unit loads, P , P and M , shall be the greater of
DH DV D
a) operating loads determined from the geometry and operation of the jumbo unit. The most critical
position of the boom shall be consid
...