aatc design criteria and guidelines for surface infrastructure - mechanical & structural

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AATC DESIGN CRITERIA AND GUIDELINES FOR SURFACE INFRASTRUCTURE - MECHANICAL & STRUCTURAL

IMPLEMENTATION DATE 11/22/2013

DOC NO AATC000859

THERMAL COAL


AUTHORISATIONS NAME POSITION SIGNATURE DATE

AUTHOR Schmidt, Thinus Principal Mechanical

Engineer

REVIEWED BY Ford, Julian

AATC Head of Engineering,

Technical Services and Projects

REVIEWED BY Mathews, Darren AATC Head Opencast

Engineering

REVIEWED BY Maapola, Phanki

AATC Head of Engineering, Underground Operations

APPROVED BY Coetzee, Johnny AATC Head of

Engineering RSA


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IMPLEMENTATION 11/22/2013

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CONTENTS Page

1 AIM 4

2 DEFINITIONS 5

3 PROCESS DESIGN CRITERIA 6

3.1 Material Characteristics 6

4 MECHANICAL DESIGN CRITERIA 7

4.1 Design Codes and Standards 7

4.2 Surface materials handling systems – General requirements 7

4.3 Environmental Aspects 13

4.4 Standardisation 13

4.5 Belt Conveyors 14

4.6 Chutes 30

4.7 Mechanical Design – General Requirements 32

4.8 Fire protection 36

4.9 Pipework and Valves 36

4.10 Platework and Lining 47

5 STRUCTURAL DESIGN CRITERIA 52

5.1 Plant Buildings and Structures 52

5.2 Conveyor Structures 53

5.3 Walkways, access, platforms and flooring 54

5.4 Cladding of structures 55

5.5 Civil 57

5.6 Corrosion Protection 57

6 INTERFACES 60

6.1 Civil 60

6.2 Electrical Engineering 60

6.3 Instrumentation 61

7 REFERENCES 62

7.1 AA Standards and Specifications: 62


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7.2 National Standards and Specifications 63

8 REVISION HISTORY 64

9 APPENDICES 65

9.1 Appendix A: Preferred Vendor List 65

9.2 Appendix B: Standard Drawings 66


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1 AIM

The purpose of this document is to provide generic design criteria and guidelines for AATC surface infrastructure projects related to the Mechanical and Structural Steel Engineering disciplines. Certain basic civil aspects which directly impact on the mentioned disciplines are also covered but not from a design perspective.

Underground systems are covered under the AATC Underground Conveyor Design Guide document number AATC000860.

The intent of the document is not to present detailed design information for each component and system, but rather to outline guidelines and certain mandatory requirements not contained in specifications. Any particular information not contained herein must be developed during detailed design stage to support equipment and erection specifications.

This document shall be read in conjunction with the relevant Anglo American Specifications as quoted, which shall be issued as part of the equipment and/or contract enquiry documents.

In project specific cases where the need arise to deviate from any item in this document a concession must be submitted to and approved by the Engineer in writing.

Where an item is specified with a note stating “or equivalent”, the Engineer shall be requested in writing to grant permission to use such an “alternative”.


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2 DEFINITIONS

Term Definition

AATC Anglo American Thermal Coal

AFRS Anglo American Fatal Risk Standard

APW Anglo Projects Way

Approved Approved by the Engineer in writing or signature

BMH Bulk Materials Handling

BS British Standard

BS EN British Standard European Norm

CEMA Conveyor Equipment Manufacturers Association

CMA Conveyor Manufacturers Association

DMR Department of Mineral Resources

Engineer AATC Discipline Engineer assigned to the project

ESS Electronic Soft Starter

FEL Front End Loading of Project Phases (Refer to APW documentation)

HAZOP Hazard And Operability Study

ISO International Standards Organisation

MCC Motor Control Centre

OEM Original Equipment Manufacturer

PFD Process Flow Diagram

P & ID’s Piping And Instrument Diagrams

PLC Programmable Logic Controller

PSD Particle Size Distribution

SANS South African National Standard

SIB Stay in Business

ROM Run of mine

VSD Variable Speed Drive


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3 PROCESS DESIGN CRITERIA

3.1 Material Characteristics

3.1.1 General design parameters

The table below indicates the design parameters to be used in all material handling systems. Material flow tests should ideally be conducted during FEL 2 so that the design data is available when FEL 3 commences.

Duty The plant and equipment shall be designed to operate 24 hours a day, 7 days a week; with one 8 hour maintenance shift a week.

ROM material

The nature of the reserve must be understood i.e. virgin reserves versus previously undermined areas.

Consideration must be given to previously undermined operations where the top size of lumps cannot be accurately controlled and instantaneous slugs of 100 % stone may occasionally occur in the feed stream. Where weathered coal exists, the total instantaneous throughput tonnage may be fine material.

When designing systems, the scale of the operation must be considered since design approach and methodology are not the same for a 0.5 MTA mini-pit as opposed to a 20 MTA operation.

Contamination Previously undermined reserves may contain a considerable amount of timber and tramp metal.

Raw coal PSD The particle size distribution can be considered typical of open cast operation but confirmation from metallurgy is prudent. It is not uncommon to encounter 2 m top size lumps.

Bulk density (volumetric)

Volumetric calculations to be based on lowest anticipated bulk density unless a correction factor is applied in the calculations.

Bulk density (mass) Power calculations to be based on highest anticipated bulk density unless a correction factor is applied in the calculations.

Total moisture content

Average 12 % Dry season 8 % Wet season 15 % (Guideline only, reserve specific)

Angle of repose 38° (Guideline only – project specific data required for detail design)

Bulk densities

Raw coal : 900 to 1300 kg/m3 Product : 900 to 1100 kg/m3 Discards : > 1100 kg/m3 Guideline only - For specific project information refer to the bulk solids flow reports or confirm with AATC metallurgy.

Table 1 – General Design Parameters


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4 MECHANICAL DESIGN CRITERIA 4.1 Design Codes and Standards

4.1.1.1 The design and construction of all works shall be carried out in accordance with all

applicable laws, regulations and standards. This document is regarded as a guideline with certain mandatory requirements. Applicable standards which are not listed must be included by the designer or supplier.

4.1.2 Anglo American Specifications

4.1.2.1 The list of Anglo American Specifications referred to in this document is provided in Section 7 References.

4.1.3 Applicable Codes, Standards, Acts and Regulations

4.1.3.1 Unless specifically stated otherwise, designs shall be based on the applicable parts of the latest revision of the Codes, Specifications, Standards, Regulations and other documents. The list of the codes, specifications, standards and regulations referred to in this document provided in Section 7 References. In addition, the design must comply with local legislation and regulations as stipulated by the DMR.

4.1.3.2 In the event of conflicting requirements, the most stringent will apply. 4.1.3.3 For conveyor designs, ISO 5048 will take preference over CEMA requirements. 4.1.3.4 The following protocol will be used where specifications are required:

1) Available Anglo American specifications must be used.

2) If no Anglo specifications are available, refer to the most relevant SANS specification.

3) If no SANS specifications are available, international specifications recognised within the industry may be applied.

4.2 Surface materials handling systems – General requirements

4.2.1 General

The layout of materials handling systems must be conducted in view of an optimal balance between operational costs and capital expenditure. Where the implementation of new technology is considered viable, a trade off study must be done against the conventional approach. Designs must be carried out with consideration for the reduction of fines generation.

4.2.2 Tips – General

The layout of tips must be such that free access with mobile cranes is possible from both sides. The topography of the location can often be used to minimise the ramp height and excavation depth. However, free drainage is mandatory. On certain large and more complex tip configurations, typically associated with previously undermined reserves, an overhead crane may be required. On these installations only roof sheeting will be required.


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4.2.3 Dust hood

Passive dust suppression is mandatory on all new tip installations. The passive system may be aided by the intermittent use of a spray system as and when required.

The volumetric design of the hood structure is somewhat specialised but essentially it needs to provide enough volume so that the displaced air, as a consequence of the tipping operation, can settle down such that dust pollution is minimised.

Installations must be equipped with used fire retardant conveyor belt installed in a specific internal baffle arrangement to enable dust particles to settle out.

The ratio of the dust hood width/truck width must fall within a range of 1.8 to 2 in order to ensure easy truck manoeuvrability and to avoid mechanical damage. Columns must ideally be integrated with the wing walls and bin structure to eliminate structural damage.

The walls of the bin must be raised to prevent damage to the sheeting by large rolling lumps when the bin is full or where grizzly cleaning operations are anticipated.

Safe access to the roof is required for the maintenance of lighting etc.

The orientation of the hood must ideally be such that the prevailing wind direction is towards the tipping face i.e. into the hood.

4.2.4 Jockey Slab

The jockey slab must be equipped with cast-in rail liners to facilitate cleaning operations.

The ideal height of the wheel stopper must be 67% of the wheel diameter. Special consideration is required where different truck types are anticipated. The steel cover plate must be submerged well into the concrete such that it cannot be lifted during cleaning operations by a front end loader. Avoid any ledges that can initiate material build up.

Where a concrete bin is utilised, the jockey slab will be integrated with the wing walls and bin structure. For a steel bins however, the jockey slab will be independent.

4.2.5 Tip static grizzly

The viability of using a static grizzly depends on the specific operations. The guideline is to equip mini-tips with low throughput tonnage with a static grizzly to ensure that smaller, cost effective equipment can be selected.

The consideration for a grizzly must be done within the context of downstream equipment selection.

The grizzly aperture is reserve specific but within AATC 1.2m x 1.2m is commonly used.

Static grizzlies are not permitted on large operations where previously undermined areas


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will be mined. The philosophy is that large lumps can be removed safer at an inspection feeder at a lower level in the tip, which is equipped with an overhead crane.

Grizzly bars and support structures must be designed to safely withstand the impact energy associated with the tipping operation and where applicable, the hydraulic rock breaker.

4.2.6 Tip static grizzly – cleaning operations

It is not permitted to use a fixed pecker in conjunction with a dust hood.

The use of a TLB may be functional on mini-pit operations but on larger tips, the reach may be insufficient. A track mounted excavator, equipped with a hydraulic hammer may be required.

On mini-pit operations, it may be more efficient to remove and stockpile oversize rock instead of attempting it through the grizzly.

4.2.7 Tip bin

The volume of the tip bin is generally taken as 2 to 3 times the capacity of the hauling trucks but must be justified by simulation or calculation.

Steel bins should only be considered for an anticipated mining life of less than 15 years because of corrosion considerations. All other installations must be constructed out of concrete.

Concrete bin constructions can be integrated well with the dust hood, wing walls and wheel stoppers.

Concrete bins must be equipped with casted in rail liners.

Discharge arrangement designs should be based on mass flow system. Appropriate material release angles to be applied.

4.2.8 Tip feeders

The draw off pattern achievable is a function of the geometry of the interfacing plate work. The design must be such that tipping space is continuously created at the tipping face of the bin.

Big lumps must specifically be catered for on large operations. However, at small operations, a trade off is required to ensure that capital cost remains at an acceptable level.

Where previously undermined areas are included in the mining plan, the preference is to use a conventional apron feeder. Apron feeders are generally orientated in line with the tipping face such that dribbling is collected on the clearance conveyor.


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Flight bar feeders may be used on mini-tips and larger operations where virgin areas are mined but the bin interface requires careful consideration.

The orientation of these feeders i.e. parallel or perpendicular to the tipping face is project specific.

A perpendicular arrangement provides good maintenance access but the tail end of the tip clearance conveyor cannot be utilised as a spillage conveyor. A parallel configuration is therefore preferable when using a conventional apron feeder.

A perpendicular arrangement is usually preferable when using a flight bar type feeder but not mandatory.

4.2.9 Grizzly and observation feeders

Grizzly feeders are generally associated with tips used at previously undermined reserves where jaw crushers are installed. Large tramp metal chunks, oversize lumps and timber can be removed with an overhead crane from the observation feeder deck. Safe access onto the observation feeder deck is a key design consideration. The decision to utilise these feeders are project specific.

4.2.10 Rock breaker

Rock breakers are generally associated with tips equipped with observation feeders such that large lumps can also be broken at sizer or crusher feed-ends.

The guideline rating for the hydraulic hammer is 2000 Joule.

4.2.11 Primary crushing

Jaw crushers are considered more robust than mineral sizers and are therefore preferred where previously undermined reserves are mined. The large lumps associated with this type of operation generally lead to the selection of the largest crusher available on the market i.e. 80 x 60’’

Where virgin reserves are mined, mineral sizers are preferred.

The preferred feed configuration is such that the feed stream lands parallel to the sizer shafts such that fines can easily pass through the sizer without being scrolled to the sides. A perpendicular feed arrangement is also possible but will result in uneven wear and may lead to throughput constraints when the sizer is operating close to its capacity limit.

4.2.12 Secondary crushing

A scalping operation between the primary and secondary crushers or sizers will usually enable the selection of a smaller secondary machine with reduced wear and maintenance.

The removal of tramp metal is problematic where the secondary sizer is positioned


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directly below the primary sizer. This configuration must be avoided.

4.2.13 Tertiary crushing

Although the throughput tonnage processed by the tertiary crushers is often lower than upstream crushing operations, tertiary crushers often work the hardest and are often where excessive wear, throughput and oversize problems occur.

Special consideration must be given to the nature of the operation. During the rainy season, when wet material is processed, throughput problems may occur if the sizer is marginally selected.

It must be noted that where a guaranteed product size must be delivered i.e. Eskom product, mineral sizers are not suitable on its own without a final screening operation. As internal wear occurs, oversize material will be encountered. Granulators are generally utilised where stringent final product size specifications is stipulated.

4.2.14 Tramp metal removal

The most effective tramp metal removal configuration is where the magnet is positioned above a material trajectory. Conventional overband magnets are however often sufficient. Where excessive amounts of tramp metal are anticipated, the magnet should be positioned at a perpendicular transfer. This configuration will also make the removal of long rails and timber logs possible. Where magnets are positioned above a transfer, stainless steel pulleys are usually only required for belt speeds below 2 m/s.

4.2.15 Rotary breakers

A rotary breaker should not be used as a primary crusher on opencast applications. The impact energy associated with large lumps is problematic.

A concrete support structure is preferred. A conservative structural design approach is advisable.

A scalping operation upstream of the rotary breaker should be avoided unless the use thereof can be justified.

4.2.16 Silos and bins

The general guideline is to use steel for the construction of bins with a capacity of less than 500 ton and concrete for silos in excess of 1000 ton. The range between 500 and 1000 ton may be constructed out of steel or concrete based on economical or other considerations.

Where the anticipated life of the project exceeds 20 years, concrete construction is preferable.

Silo diameters commonly used includes 13, 16, 20 and 22 m.

Where concrete roofs are used on silos, dust explosions must be catered for by means


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of explosion panels.

Silos and bins are generally designed for expandable flow conditions in the upper region with mass flow conditions at the discharge hopper.

4.2.17 Silo and bunker trade-offs

Although several project specific considerations will influence the selection, Table 2 below is to be used as a guideline.

Surge / storage structure Approx capacity range (m3) Comment

Bin, steel Up to 1 000 Project requirements may dictate concrete construction.

Silo 1 000 to 6 000 Consider bunker for > 5 000 m3

Silo, rail load out ± up to 10 000 Bunker with rail load out bin must be evaluated.

Bunker, (RE C) ± 2 500 to 15 000 Project specific constraints may rule (RE) option out.

Bunker, longitudinal

RC / RC P / RE L > 6 000

Where:

RC = Reinforced concrete

RC P = Reinforced concrete with pre-cast elements

RE C = Reinforced earth, circular

RE L = Reinforced earth, longitudinal

Whenever the required surge or storage capacity is close to the threshold values indicated above, a trade-off study would be required unless an option can be ruled out because of specific project requirements or constraints.

Table 2 – Selection guideline for silos & bunkers

4.2.18 Stockyards and equipment

The possibility of future expansion must be considered when conducting layouts. Stockyards should, where possible, not be located within a rail loops unless sufficient space is available for future expansions.

Where possible, stockyard by-pass conveyors must be included.

4.2.19 Escape access

The need for escape access, cross over’s at conveyors and especially parallel conveyors where personnel can be entrapped in case of fire, must be determined by risk assessment.


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4.3 Environmental Aspects

4.3.1.1 Environmental aspects are regulated by local Legislation. Items listed below merely highlights some important considerations directly related to designs.

4.3.1.2 All designs shall be carried out such that the impact that mining operations have on the environment is minimised. Of particular concern are water, dust and noise pollution.

4.3.1.3 All water that arises within the conveyor area shall be contained and channelled to the polluted water handling system.

4.3.1.4 Overland conveyors transporting material outside the boundaries of the polluted area must be equipped with belt turnovers at the head and tail to avoid material carry back along the conveyor. Turnovers are problematic on wide conveyors. Overland conveyors used for AATC projects are generally less than 1500 mm wide such that turnover designs are possible.

4.3.1.5 Generation of dust shall be strictly controlled by avoiding degradation of the coal and the dust that is generated shall be controlled by both passive and active means.

4.3.1.6 The noise generated by the plant shall be minimised by selecting inherently quiet equipment and processes and, where unavoidable, acoustic enclosures.

4.3.1.7 Special note shall be taken for electrical drives that are electronically controlled which have an inherent noise generation through the motor drive shaft. This shall be taken into account with respect to noise abatement. Noise abatement technical information shall be obtained from the drive manufacturer. Resonance points, if applicable, shall be provided in the ramp-up to full speed.

4.4 Standardisation

4.4.1 General

The selection of major equipment must not be done in isolation. Equipment already used within AATC must be considered.

When selecting conveyor belting for purposes of an FEL 3 Study or Detail Design, belting already used at AATC operations must be considered.

For SIB type project designs, it is essential to stick to standard equipment and supplier brands which are already used at the specific Operation unless the deviation can be motivated.

A preferred vendors list is provided in Appendix A: Preferred Vendor List. Vendors not listed are not necessarily excluded nor are vendors tabulated in order of preference.


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4.5 Belt Conveyors

4.5.1 Conveyor Design Criteria

Conveyor designs are to be in accordance with the latest ISO 5048 Standard, Continuous mechanical handling equipment and guidelines prepared by Conveyor Equipment Manufacturers Association (CEMA).

Conveyors must be designed for continuous operation and starting under full design load.

4.5.2 Standardisation

4.5.2.1 The conveyor designer is to give consideration to economical design while rationalising mechanical components for optimum spares holding and interchangeability. The process shall be based on component priority selection as follows:

Priority 1 – belting Priority 2 - drives Priority 3 - pulleys Priority 4 – other

In view of power savings, “right-sizing” must be traded off against standardisation.

4.5.3 Vertical inclination

4.5.3.1 The maximum permissible angle of inclination shall be dictated by the material, particle size distribution, type of loading, belt speed etc. of the particular design.

4.5.3.2 The maximum inclination angle shall however not exceed 13°.

4.5.3.3 Where material run-back on the conveyor is expected e.g. conveyors exclusively handling screened oversize or spherical type lumps, conveyor inclinations will be kept below 10°.

4.5.3.4 For stacker boom belts, the inclination angle, and subsequently the angle at which material is loaded, will be limited to 14°.

4.5.3.5 For normal loading conditions, with the tail pulley positioned for full trough, the conveyor incline should be 0.5° to provide effective drainage.

4.5.3.6 The maximum incline at loading shall not exceed 5°

4.5.4 Vertical curves

Dynamic calculations must be performed for all vertical curves to ensure safe and reliable conveyor operation. Calculations must be based on the worst case combination of conveyor loading and geometry.

A suitable factor, taking cognisance of the start-up device, must be applied to the


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calculated dynamic start-up tensions when calculating the required concave radius.

4.5.4.1 For concave curves, the following criteria should be met:

On all conveyors featuring trippers (eg. stacker feed conveyors), the belt shall not lift off the radius during start-up or normal running when loaded to 15 % of the conveyor’s maximum design capacity in the curve only, with the rest of the belt fully loaded for the load-case causing highest tension in the curve. The belt mass used for these calculations shall be based on 50 % top cover wear. Belt-lift control must be considered where it is not possible to satisfy these criteria.

For cases where the rear tangent point is close to the feed chute, the above calculation shall be repeated with load up to the rear tangent point and no load on the belt in the curved section to ensure that the belt will never lift into the chute or skirt sections.

On all other conveyors, the belt shall not lift off the radius during start-up or normal running when empty. The belt mass used for these calculations shall be based on 50 % top cover wear.

Centre tension in the curve area shall be limited to 115 % of the maximum rated tension for the particular conveyor.

The edges of the belt shall not buckle in the curve area.

4.5.4.2 For convex curves, the following criteria should be met:

The additional stress imposed on the idlers as a result of the convex curve shall not lead to idler shaft deflections and idler bearing lives that do not comply with Anglo specifications. Edge tension in the curve area shall be limited to 115 % of the maximum rated tension for the particular belt. The centre of the belt shall not buckle in the curve area.

4.5.5 Horizontal curves – overland conveyors

Belt wander must be considered for all conditions of loading as well as for all weather conditions and must be limited to approximately 100 mm as a guideline.

It is recommended to use stringer widths for the next belt size up within horizontal curves. Throughing idlers will then be for the selected belt width while return idlers will be for the next size up.

The layouts for horizontal curves must be based on a minimum radius of 4 km. Where route requirements and existing infrastructure dictates otherwise, a smaller radius may be allowed on concession provided that the design can be justified.

4.5.6 Conveyor Dynamics


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4.5.6.1 All conveyors shall be analysed for behaviour during starting (for vertical curves), coasting and where applicable, braking.

4.5.6.2 For conveyors >1 km, or where special profiles are encountered, dynamic transients and the application of torque prior to starting must be considered.

4.5.7 Conveyor Capacities, Widths and Loading

4.5.7.1 Conveyor design capacities shall be calculated from the Life of Mine plan and recorded on a flow sheet. Only the approved flow sheet capacities shall be used for detail conveyor designs.

4.5.7.2 The width of belt shall be selected as follows:

For a maximum lump size up to 180 mm: Flow sheet peak capacity and the standard recommended edge distance shall be used according to the latest ISO 5048 Standard, Continuous mechanical handling equipment and CEMA.

The designer shall optimise belt speed and installed power by achieving as close as possible a belt loading of 80 % full at the installed power. Where designs incorporate trippers and multiple feed points, the belt loading must be reduced. For maximum lump size over 180 mm: As a minimum requirement, the belt width shall be maximum lump size x 4 and then selecting the closest standard belt width above this value. Thereafter, the criteria above for a maximum lump size below 180 mm shall apply.

4.5.8 Feed factors

4.5.8.1 In order to cater for fluctuations in feed to the conveyors, the following feed factors shall be used as a guideline:

Application Feed factor

Belt and apron feeders where steady stream controlled feed is expected.

1.1

Vibrating, table feeders etc. where surges and significant short term flooding may occur on the receiving conveyor belt

1.15 - 1.25

(depending on the feeder type)

Reciprocating feeders 1.7

Where there is no feed control e.g. Langlaagte chutes under hoppers / box fronts.

2.0

* The above factors will be incorporated in the conveyor designs but will not be reflected in the flow sheet capacity. Table 3 – Feed Factors


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4.5.9 Conveyor belt speeds

4.5.9.1 The general philosophy of wide and slow belts shall be adopted with the following recommended speeds:

Incline conveyors < 4 m/s

Plant surface transfer conveyors 2 to 3 m/s

Overland conveyors < 4.5 m/s

4.5.9.2 For typical transfer heights in the chutes, a nominal 250 mm lump will produce up to

900 Joules on impact with the receiving belt, which is the upper limit of the allowable impact energy. It therefore follows that the initial kinetic energy of the lumps entering the transfer chutes be minimised by way of conservatively slow belt speeds.

4.5.9.3 Where multiple feed points are required, lower speeds must be considered to reduce spillage.

4.5.10 Conveyor artificial friction factor “f”

4.5.10.1 The guideline design values for the coefficient of friction f for idler resistance and flexure of the material and the belts, are as follows:

Overland conveyors :fc = .019 fr = .017

Curved overland conveyors :fc = .0195 fr = .018

In-plant conveyors :fc = .02 fr = .022

In-plant ROM conveyors :fc = .022 fr = .022

4.5.10.2 A friction factor of 0.022 should be used for both underground and surface conveyors with an adjusted length factor Lo of 60m for all conveyors longer than 100 m.

4.5.10.3 In extremely cold conditions during winter mornings a load factor of between 1.1 and 1.2 should be applied when selecting the sizes of the drives.

4.5.10.4 The above factors serve only for static analysis. Visco-elastic friction, indentation resistance and idler resistance calculations shall be included in the design of long overland conveyors.

4.5.11 Conveyor Drive Systems

4.5.11.1 The design, selection and layout of the drive systems for conveyors shall be determined


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by the power, tension and wrap requirements.

4.5.11.2 The absorbed power at the drive pulley is calculated in accordance with the latest ISO 5048 standard, Continuous mechanical handling equipment, using the artificial friction factors “f” being selected from section 4.5.10.

4.5.11.3 The absorbed power at the motor is that calculated at the pulley shaft, divided by the combined gearbox and fluid coupling efficiency, approximately 0.94, depending on selection, where fitted above 22 kW.

4.5.11.4 For VSD units, the efficiency is taken as 0.97, unless otherwise certified by the OEM.

4.5.11.5 The absorbed power at the motor is then multiplied by a factor of 1.1 for conveyors with single drives. Thereafter, the next most suitable motor size up is selected in each case as well as considering standardisation. For multiple drives, load sharing must be considered. Although a factor of not less than 1.1 is to be applied, specific consideration is required to ensure that large drives are not oversized.

4.5.11.6 The drives for incline, surface transfer and main overland conveyors shall be sized for the full length of conveyor as per the conveyor route profiles and design capacity.

4.5.11.7 Single head drive configurations may be considered for large conveyor drives (> 250 kW) where the head is elevated one floor level only. Special consideration must be taken to ensure that proper maintenance can be done on scrapers and that facilities are available for the change out of pulleys, motors and reducer. A trade-off must be done against a ground level installation.

4.5.11.8 Where drive sizes are 250 kW and smaller, elevated drive installations (in excess of a single floor) may be considered provided that provision is made to remove the drive and drive pulley to a conveniently located platform which can be accessed via mobile cranes.

4.5.11.9 Head pulley drives up to 90 kW is permitted on cantilevered conveyors, such as over stockpiles.

4.5.11.10 If the drive is at the head end of the conveyor, the head/drive pulley shaft should be extended so that a clearance of approximately 500 mm is obtained between drive and conveyor steelwork.

4.5.11.11 Right-angled, bevel helical gearbox units are to be used in a torque arm configuration. The output shaft of the gearbox will be fitted with a rigid Bikon-type coupling for mounting onto the drive pulley coupling.

4.5.11.12 The drive station layout shall be such that torque arms are always under compression.

4.5.11.13 The drive station layout shall be such that the belt is always driven on the clean side.

4.5.11.14 The selection guideline table for drive preference on various conveyor applications is shown below.


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Type conveyor VSD Fluid

Coupling Electronic Soft Start

Remark

U/G Section No 1st No Dusty, Low tech

U/G Trunk – 1500 m 1st 2nd No Variable Speed (load)

Shaft > 50 m lift 1st 2nd No Start-up and inspection

Overland > 2 km 1st 2nd No Start-up and inspection

Plant < 2 km 2nd 1st No F cplg – Start time OK

Plant – Single drive No 1st No

Plant < 110 kW No 1st 2nd ESS more cost effective

No – Not permitted, 1st – Preferred choice, 2nd – Alternative option

Table 4 – Drive preference for various conveyors

4.5.12 Couplings

4.5.12.1 Fluid couplings will be fitted on the high speed side of all drives exceeding 22 kW where VSD or Electronic starters are not provided.

4.5.12.2 All couplings shall be complete with guards.

4.5.12.3 All low speed couplings shall be of the rigid flange type, accurately aligned and fitted to shafts via locking elements (no keyways allowed on shafts). The drive supplier shall fit the rigid couplings to the pulley at the pulley supplier’s premises.

4.5.12.4 Drives with an installed power exceeding 22 kW shall be fitted with a soft starter i.e. fluid coupling or electronic.

4.5.12.5 For long overland conveyors with high inertia where the start-up times would be in excess of 50 seconds (which is the limit of the capability of fluid couplings), Variable Speed Drives (electrical VSD’s) are selected.

4.5.12.6 The overhung on motor output shafts must be checked when using large fluid coupling sizes. Jack shafts may be required to support the fluid coupling.

4.5.13 Belting

4.5.13.1 Steel cord conveyor belting shall comply with the latest AA Specifications, Steel cord reinforced conveyor belting (AA_SPEC_377022) and Steel cord reinforced conveyor belting (SANS 1366).

4.5.13.2 All fabric conveyor belting shall comply with the latest SANS Specification, General purpose textile reinforced conveyor belting (SANS 1173).


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4.5.13.3 PVC impregnated solid woven conveyor belting shall comply with the latest SANS Specification, Fire retardant textile reinforced conveyor belting (Solid woven PVC, SANS 948 and SANS 971).

4.5.13.4 All conveyor belting shall be selected with consideration of the standardised list of belting already in use at Anglo Coal plants.

4.5.13.5 Ply belting to be natural rubber, minimum 3 ply with suitable top and bottom covers, minimum 3 mm and 2 mm respectively. The top to bottom cover ratio is not to exceed 3:1.

4.5.13.6 Conveyor belt final selection shall be based on the calculated tension taking standardisation into consideration.

4.5.13.7 In determining the length required allowance shall be made for hot vulcanized splicing.

4.5.13.8 Mechanical clips may be used in emergency situations only.

4.5.13.9 During belt and cover selection, consideration must be given to minimise the risk of igniting flammable gas during installation and operation. Belt selection must also be done considering the possibility of burning coal to minimise the risk of fire and noxious gasses.

4.5.13.10 In selecting the belt type, the following table must be used as a guideline:

Area application Belt type

Tip, raw coal

Ply belts where impact permits.

Solid woven to be considered on tip clearance belts and where significant steel contamination is anticipated.

Sacrificial belts and applications where high abrasion is expected are generally equipped with ply belts.

Evaluate the possibility of burning coal / spontaneous combustion.

Plant Ply belts

Stock yards Ply belts

Interconnecting overland conveyors shorter than 1 km

Ply belt

Solid woven where justified, avoid steel cord.

Overland conveyors Tensions normally require steel cord but consider solid woven where possible.

Shaft & high lift conveyors

Tensions normally require steel cord but consider solid woven where possible.

Table 5 – Belt type selection


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4.5.14 Belt service factors

4.5.14.1 The following minimum service factors shall be applied to all conveyors based on the normal steady state tensions:

Solid woven belting : 10 Fabric ply belting : 10 Steel cord belting : 6.67

4.5.15 Belt Jointing

4.5.15.1 Conveyor belts will be joined in accordance with the latest Anglo American Specifications – (Cold splicing of plied (textile) conveyor, AA_SPEC_377010), (Splicing of solid woven conveyor belting, PVC & PVG(Nitrile), AA_SPEC_377088) and (Splicing of steel cord reinforced conveyor, AA_SPEC_377033) whichever is applicable to the selected conveyor belting.

4.5.15.2 The conveyor belt splicing shall be done in consultation with the conveyor belt manufacturer.

4.5.16 Belt installation Winch/Splice station/Replacement and maintenance of belting

4.5.16.1 Provision shall be made to provide easy access for replacement and repair of belting. A belt replacement study is to be conducted.

4.5.16.2 A belt reel holder will be installed at the head end or tail end of every conveyor belt on surface. In cases where the reel cannot be accommodated at the head or tail, provision will be made at the take-up section.

4.5.16.3 A belt maintenance station shall be provided such that:

The belting to be replaced may be easily pulled off the conveyor. The replacement belting may be easily pulled onto the conveyor without the risk

of damaging the belting. Splices may be easily and accurately made.

4.5.16.4 The splicing area is protected from the elements.

4.5.16.5 Provision will be made to install suitable winches to facilitate the initial and any subsequent pulling-in of a new belt. These will be located to pull the belt up from the tail end as well as to pull the return side down from the head end.

4.5.16.6 Sheaves may be permanently mounted but the winches will be installed on prepared mounts and connected as required.

4.5.16.7 The belt maintenance station for overland conveyors shall be provided with outdoor industrial power outlets for 220 volts (2x) and 550 volts (1x) and water. The floor of the


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belt maintenance station shall be concrete and shall be bunded.

4.5.16.8 Belt clamps shall comply with the CMA specification MC-01.

4.5.17 Holdbacks

4.5.17.1 A full risk assessment per conveyor belt shall be carried out prior to selection of the holdback considering:

Material loading combinations on conveyor. Drive loading conditions during start–up, abort start, normal running and jammed

take-up or belt. Abnormal conditions such as wash down. Stored energy. Repair of conveyor components with a fully loaded incline. Maintenance belt clamp of 60 kN capacity. Assistance from anti-runback idlers. Load release.

4.5.17.2 Where the design dictates the need for a holdback, external or reducer integrated units may be considered.

4.5.17.3 Slow speed backstops, mounted directly onto the drive pulley shaft or the intermediate reducer shaft, are preferred.

4.5.17.4 High speed holdbacks, fitted between the motor and the reducer, may be considered for conveyors equipped with single drives.

4.5.17.5 Where it is desired to have a high speed holdback installation on a multiple drive configuration, torque limiting type devices are required to ensure load sharing.

4.5.17.6 For external holdbacks, a horizontal mounting configuration will reduce bearing loading and is therefore preferred.

4.5.17.7 Although stiff support steel is required to transfer the holdback reaction forces, the torque arm end of an external unit must not be rigidly attached. This will prevent damage to the bearings of the device.

4.5.17.8 The mounting of the torque arm must not permit any slack between the device and the support steel. Cushioning between load contact surfaces is precluded.

4.5.17.9 Holdback selection must be based on the calculated runback load of the belt in conjunction with a dynamic impact factor. The holdback rating shall not be less than the maximum torque capacity of the gearbox.

4.5.17.10 Where required, turn down of the shafts may be considered to accommodate maximum bore for selected backstop, provided that permissible shaft stresses, as


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provided in AA_SPEC_371001, are not exceeded.

4.5.17.11 For standardization purposes, the selection of the internal holdbacks shall be based on the highest torque requirement across the range of affected conveyors. Standardised reducer units must be interchangeable, hence internal holdbacks must be fitted for all these units unless economical considerations dictates otherwise in which case clear visual identification must be provided.

4.5.18 Anti-runback idlers

4.5.18.1 Anti-runback idlers shall be installed to satisfy the requirements of the DMR.

4.5.18.2 Anti-runback idlers are generally not required on conveyor belts which have a lift of less than 7 m. Special cases may however occur. Calculations and a risk assessment are therefore still required.

4.5.18.3 In designing new steep incline conveyors, consideration must be given to increase the carry idler spacing to enhance the friction breaking force should a belt failure occur.

4.5.18.4 In determining the number of anti-runback idlers required, a conservative friction factor of no more than 0.3 must be used. This value caters for wet belts, condensation associated with temperature change and build up of coal dust on contact surfaces.

4.5.18.5 The following design parameters must be considered when selecting anti-runback idlers:

3-roll idler sets are preferred The installation pattern, which formed the basis of the design calculations, must

be adhered to. Clear marking is required. Emergency conditions such as the jamming of the tail pulley or feed chute

blockage must be considered. Where conveyors are equipped with 5 roll idler sets, the wing rolls should never

be fitted with anti-runback idlers since the contribution to braking friction is negligible

4.5.18.6 Anti-runback idlers can never be installed in place of a positive holdback.

4.5.19 Pulleys and shafts

4.5.19.1 Pulleys and shafts shall be strictly in accordance with the latest AA Specification, conveyor pulleys and shafts, AA_SPEC_371001 and SANS Specification, conveyor belt pulleys, SANS1669.

4.5.19.2 Drive pulleys will be lagged using 6 mm thick smooth ceramic tiles epoxy bonded using a high bond epoxy, directly to the pulley shell. Rubber lagging is acceptable for non-drive pulleys.

4.5.19.3 No conveyor pulleys shall be crowned. However, where reversible belts have been approved by concession, crowning may be required.


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4.5.19.4 The lagging philosophy of the operation shall be considered when conducting SIB designs and projects.

4.5.19.5 Plummerblocks should be the split type.

4.5.19.6 Spherical roller bearings with an adapter sleeve should be used.

4.5.19.7 Plummer blocks with its bearings to be fitted with an easily accessible grease nipple. Inaccessible grease point must be equipped with a hydraulic hose and grease block to facilitate safe remote manual lubrication.

4.5.19.13 Plummer block orientation shall be such that the bearing force acts through the base of the plummer block. Cap bolts shall never be under tension.

4.5.19.14 Bearing temperatures on critical belts will be monitored at the head, tail, drive and take-up pulleys using resistance temperature detector. (RTD)

4.5.19.15 All pulley approach points will be fitted with nip protection.

4.5.19.16 The number of pulleys must be kept to a minimum when designing new conveyors.

4.5.20 Idlers

4.5.20.1 Idlers shall be in accordance with the latest AA Specification, belt conveyor idlers and rolls (AA_SPEC_373001) and shall bear the SANS certification mark to the latest SANS Specification, conveyor belt idlers.

4.5.20.2 Idler spacing selection must be done by balancing the capital expenditure with operational costs.

4.5.20.3 The maximum allowable idler shaft deflection is limited to 8 minutes at the designed throughputs.

4.5.20.4 For the average operating throughputs, the minimum idler life is 40 000 hours.

4.5.21 Troughing idlers

4.5.21.1 All troughing idlers shall comply with the latest Anglo American specification, Belt conveyor idlers and rolls (AA_SPEC_373001).

4.5.21.2 Carry idlers shall be specified individually for each conveyor, based on the material, particle size distribution, etc.

4.5.21.3 Carry idlers shall be designed based on the peak capacity.

4.5.21.4 The 3 roll idler configurations are preferred. 5 roll idler configurations may be considered for belt widths exceeding 1200 mm.


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4.5.21.5 The preferred troughing angle is 35° although 45° and higher may also be used when justified.

4.5.21.6 The head frame or the stringers leading up to the head frame shall include a transition section to flatten the belt in accordance with the CEMA recommendations, precautions shall be taken to prevent spillage at this point.

4.5.21.7 Head and tail transitions are to be designed to run out to 0° by installing the appropriate transition idlers. 3 idler sets are generally required.

4.5.21.8 When required, the tail pulley may be positioned at half or third trough to reduce the transition distance. This is however not preferred.

4.5.21.9 Standardization across designs remains to be an important consideration.

4.5.21.10 High angle troughing idlers should be considered to eliminate long and high maintenance skirting on conveyors with multiple loading points typical for coal plant product and discard belts.

4.5.22 Impact idlers

4.5.22.1 Impact resulting from the transfer of material shall be absorbed by impact idlers.

4.5.22.2 Standard steel rolls can however be used on -20 mm material. Idlers located in impact areas are generally series 30 or 35 with 152 mm diameter.

4.5.22.3 Impact idlers shall be 45° trough, Ø159 mm rubber disk rolls to be used for coarse material.

4.5.22.4 Where impact is abnormally high, a torsion rubber mounting system is to be considered in conjunction with rubber disk idlers. The rubber torsion mounting arrangement is to be approved by the Engineer.

4.5.22.5 Idlers located within the skirted area at loading points will be mounted on quick release mountings which will allow the complete idler frame to be lowered for idler roll replacement.

4.5.22.6 Solid SKEGA beds should not be used.

4.5.23 Return idlers

4.5.23.1 Return idlers shall be specified individually for each conveyor, based on length, belt width, tracking difficulties, etc.

4.5.23.2 All conveyors 1200 mm wide and above should be 10° vee, 2 roll return idlers, subject to belt troughability and the specific detail design.

4.5.23.3 As a guideline, conveyors below 1200 mm wide should be fitted with single roll flat


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return idlers unless troughability calculations prove otherwise.

4.5.24 Take-up units

4.5.24.1 All conveyors with horizontal pulley centres 30 metres and longer will be provided with gravity take-ups, either vertical or horizontal to suit the design.

4.5.24.2 For short conveyors (less than 30 m) mechanical screw take-ups may be used.

4.5.24.3 All take-ups shall be designed to accommodate the elastic and permanent stretch of the belt, calculated from the belt modulus as specified by the belting Supplier.

4.5.24.4 In addition to belt stretch, the take-up must make provision for belt storage such that five splices in case of overland conveyors and three splices in the case of shorter plant conveyors is catered for.

4.5.24.5 Allowance shall also be made for sufficient movement for splicing, and where applicable, for rope tie offs on horizontal take-up trolleys.

4.5.24.6 On vertical gravity take-ups, deflector plates, with adjustable rubber scrapers, are required to prevent ingress of spilled material between the belt and the take-up pulley.

4.5.24.7 The take-up shall include the counterweight or winch, sheaves, steel wire rope, attachments, etc. to maintain the required belt tension under all operation conditions.

4.5.24.8 The take-up trolley longitudinal wheel centres will have a ratio of √ :1 in relation to the width of the trolley as a minimum. This aspect ratio shall apply to vertical gravity take-up carriages as well.

4.5.24.9 The take-up trolley must have locating wheels on one side and floating wheels on the opposite side of the carriage.

4.5.24.10 Provision shall be made for the take-up trolley to be locked in position, and the two belt strands entering and exiting the horizontal take-up to be clamped during maintenance activities.

4.5.24.11 A manually operated electric winch with local starting controls shall be provided on all horizontal take-up towers to facilitate raising and lowering of the counterweight box under controlled conditions.

4.5.24.12 Vertical take-up counter weight shall be provided with suitable guide channels to ensure positive location of the counterweight in the guides.

4.5.24.13 The desired counterweight mass should be made up with plate packs in a support cradle. Consideration may be given to properly drained counterweight boxes in order to facilitate the use of steel punchings or similar material, given the high cost of steel plates.

4.5.24.14 Steelwork, walkways, stairs platforms, etc. to afford safe and adequate operational and maintenance access shall be provided.


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4.5.24.15 For vertical gravity take-up, over 6m in height, belting flap to be restrained with flat return idler guides. This configuration should however be avoided.

4.5.24.16 Vertical gravity take-up should have a clearance between frame and guides of approximately 10 mm per side.

4.5.24.17 Gravity take-up towers shall be of sufficient height to accommodate the change in the length of the conveyor belting under all operating conditions with a minimum of 500mm travel distance before any object will be encountered.

4.5.24.18 Ny-lock (prevailing torque) nuts to be used on take-up frames.

4.5.24.19 Gravity take-up towers shall have a buffer at the bottom. This buffer shall be able to absorb the impact of the free falling take-up weight to prevent damage to the structural components. The preference is to use a sand box with screed closure.

4.5.25 Belt scrapers and duff chutes

4.5.25.1 A double bladed secondary belt scraper shall be fitted at all head pulleys. Scrapers shall be adjustable and self-compensating for wear. Sufficient space for servicing is to be allowed. Belt scrapers must be easily and safely accessible for maintenance purposes.

4.5.25.2 Primary scrapers are occasionally used at certain applications with success and therefore not prohibited.

4.5.25.3 All scrapings from the belt cleaner shall be deposited onto the receiving conveyor by means of a dribbling chute. The side angles of the duff chute shall be inclined such that a valley angle of not less than 70 degrees is obtained. All the corners shall be rounded such as to allow the free flow of duff material to the receiving conveyor. A chute impact angle of less than 20 degrees shall be maintained.

4.5.25.4 Dribble chutes will be lined with UHMW liners with a 6mm thick rubber backing or manufactured from stainless steel polished on the sliding surfaces.

4.5.25.5 Chutes must ideally be designed such that duff can be removed by the main material stream.

4.5.26 Belt ploughs

4.5.26.1 V-return ploughs shall be installed on the following positions:

Clean side of the return belt at tail pulleys Approach to bend pulley on vertical gravity take-ups. At drive stations prior to the HT snub pulley


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4.5.26.2 Care must be taken to position tail scrapers such that material is not scraped into the tail guard area.

4.5.26.3 Where V-return idlers are used, the positioning of the plough must be such that proper contact between the belt and plough is maintained. Flat return idlers must be provided.

4.5.26.4 Where access to one side of the belt for cleaning purposes is not available, bias ploughs shall be installed so that material is scraped off to the side where access is readily available.

4.5.26.5 Where ploughs are installed on elevated conveyors, safety precautions due to falling material shall be taken. Easily cleanable catchment boxes should be installed.

4.5.27 Skirting

4.5.27.1 Continuous skirting is to be used for multiple load points onto a single belt. Flared skirting or spaced skirting shall only be incorporated into the design with the prior approval of the Engineer.

4.5.27.2 Skirting rubber shall be 40 shore hardness or below. Used conveyor belting in skirt seal locations is prohibited.

4.5.27.3 AATC standard skirts will be installed at all single loading points.

4.5.27.4 All conveyor feed chutes shall be equipped with steel skirting to contain material at the feed point. Skirts shall extend a minimum distance of 1 m past the stabilized material on the belt. Chute skirt covers to be easily removable.

4.5.27.5 All discharges below crushers, centrifuges etc. shall be fully enclosed to eliminate spillage completely.

4.5.27.6 High angle troughing idlers may be considered to eliminate long and high maintenance skirting on conveyors with multiple loading points typical for coal plant product and discard belts.

4.5.28 Safety and guarding

4.5.28.1 All safety guards shall be in accordance with the latest Anglo American Best Practise Guideline, AA_BPG_375001

4.5.28.2 In addition, guarding shall conform to the requirements of the Minerals Act, the Mines Health and Safety Act and where these do not cover a particular condition, the Occupational Health and Safety Act (85/1993) Incorporation of Safety Standards in the Construction Regulations 2003.

4.5.28.3 Risk assessments, as envisaged by the Mines Health & Safety Act, of all operating and


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maintenance procedures shall be undertaken by the Contractor. Personnel nominated by the Company shall be involved with these risk assessments. The outcomes of these risk assessments shall be included in the appropriate operating or maintenance manuals.

4.5.28.4 Shaft mounted power packs must be equipped with safety chains in view of a past fatal accident. A standard AATC design concept is available on request.

4.5.29 Guarding design and mounting

4.5.29.1 In areas where maintenance access is required, guarding must be designed to swivel along the vertical plane on bullet type hinges. The opposite end must be fixed with bolts so that physical work must be done to gain access. This type of guards can typically be used within horizontal take-up areas of conveyors. The swivel door must be removable by two persons.

4.5.29.2 The above requirement does not apply when the removal of guarding is not required for maintenance and change-out of equipment, belt replacements etc. This type of guarding is considered to be fixed.

4.5.29.3 Fixed panels shall be mounted using M16 hot dip galvanised fixing bolts (min 4 bolts per panel). Bolts and nuts shall be easily accessible for installation of the guard. Suitably designed fixing brackets shall be used.

4.5.29.4 Where swivelling guards are not deemed possible or practical where access is required, specific care must be taken to ensure that the removal of all panels can be safely done by one person.

4.5.29.5 Guard lifting handles must not protrude into the walkways.

4.5.29.6 Greasing points must be safely accessible without the removal of guards. Inaccessible points must be equipped with a hydraulic hose and grease block located at convenient location.

4.5.29.7 Conveyor under-belt guards must be provided on elevated sections to provide a working platform to replace return idlers and to prevent large objects e.g. idlers to fall to the ground but not to cause material build-up. The preferred construction is to have welded mesh panels, welded into a frame which is bolted into the gantry steelwork.

4.5.29.8 Guards shall be painted to AA_SPEC 164050_Corrosion Protection of steelwork with coatings and colour coding to AA_SPEC 164051_Plant Colour Coding.

4.5.29.9 Materials of construction and panel mass to comply with the table below:


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Guard panel type Frame construction Guard mesh Total mass (kg)

Fixed 50x50x6L Flatex type 348 / Eq 50

Swivel 50x50x6L Flatex type 348 / Eq 50

Light weight removable None 100x20x3 Specimesh M389 / Eq* 25

Under-belt 50x50x6L** 100x100x10 welded mesh Not restricted

*Aperture size subject to specific application.

**Span dependent, serviceability may be relaxed on concession. Table 6 – Guarding design and mounting

4.6 Chutes

4.6.1.1 The minimum width of the conveyor feed chutes (measured inside of liners) shall be 2,5 x the particle size. The width of such feed chutes shall not exceed 2/3 of the conveyor belt width.

4.6.1.2 Chutes shall be designed to pass the peak load continuously, without spillage or build-up, and to transfer it to the receiving equipment smoothly and equally distributed across the receiving equipment. The chute shall also pass the maximum lump size without blocking, hanging-up or spilling or excessive wear, and shall transfer it to the receiving equipment such that the possibility of damage is minimized.

4.6.1.3 Chute design shall accommodate dust extraction and suppression requirements where applicable (on transfers within buildings, chutes carrying dry coal). The velocity of dust shall be kept to a minimum regardless of whether dust extraction or suppression is applied. Connection flanges shall be supplied for dust suppression or extraction equipment where such systems are required.

4.6.1.4 The impact pressure on the chute and on the receiving equipment shall be kept to a minimum and shall not exceed 8 kPa.

4.6.1.5 The angle of impact, i.e. the angle between the material stream and the impacting surface, shall be minimised and shall preferably be less than 20°.

4.6.1.6 Suitable support for the chute shall be provided. In designing the chutes, the forces likely to be encountered as a result of large lumps passing through the chute shall be taken into account.

4.6.1.7 Where appropriate, deflector chutes must be provided at ploughs, take-up and drives.

4.6.1.8 When chute plates have to be stiffened, care must be taken in positioning stiffeners so that no water traps occur.

4.6.1.9 Although chutes need to be suitably stiffened in line with the liner selection, over stiffening must be avoided.

4.6.1.10 New ceramic tiles have a high co-efficient of friction, which must be considered when


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conveying fines.

4.6.1.11 Light weight chute inspection doors must be provided with welded hinges. To prevent finger injuries, these doors shall always open sideways, never to the top or bottom.

4.6.1.12 Where possible, the head snub pulley must be located within the main chute so that the fines can be carried away with the main flow of material. The chute back plate must be positioned such that there will be no build-up of the fine material.

4.6.1.13 The guideline for the required clearance between the belt and chute is obtained by the ratio of the selected belt width divided by 12.

4.6.1.14 In order that degradation of material and belt wear may be minimised, all transfer chutes shall be designed in accordance with the following principles:

All chute designs shall be based on friction characteristics obtained from bulk solids flow test for material on material and material on liner surfaces,

In determining chute angles, the co-efficient of friction between the wear material and the coal shall be taken into account.

The functional design of transfer chute arrangements shall prevail over mechanical and structural considerations,

Material velocity throughout the entire chute shall be designed in accordance with measured friction characteristics for direct sliding and sliding under impact conditions,

Material transferred to chutes shall impinge on the chute at the least practical angle of impact,

Where unavoidable and to eliminate impact wear in the top section of the chute, in-line dead boxes will be permitted.

Where a chute transfers material onto a belt conveyor, the difference in the velocities of the material in the direction of the conveyor, and the belt shall be within 10% of the belt velocity for average friction characteristics of the material on the chute liner surface,

The kinetic energy of the largest particle reasonably anticipated on a receiving conveyor belt shall not exceed 500 joules,

Where the stopping time of a conveyor is such that it may deliver more material to the receiving equipment than the receiving equipment can absorb without the possibility of spillage or blockage overloading, provision shall be made for the conveyor head chute to accommodate the overrun material. The amount of overrun material to be accommodated shall be based on the peak capacity of the conveyor,

The chute angle at the bottom of the chute shall be minimum 5° steeper than the friction angle for direct sliding.

4.6.1.15 Transfer point arrangements must be designed to minimise the fragmentation of coal.


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4.6.1.16 Blocked chute detection will be installed at all conveyor discharge ends in accordance with the latest AA Specification, Conveyor belt protection systems (AA_SPEC_673018).

4.6.1.17 Also refer to general plate work and lining requirements under section 4.10 Platework and Lining.

4.7 Mechanical Design – General Requirements

4.7.1 Design

4.7.1.1 All equipment shall be designed: To be intrinsically safe and easy to operate and maintain, To facilitate inspection, maintenance, cleaning and repairs, To ensure satisfactory operation under the conditions prevailing at the site of the works, To run without undue vibration or excessive noise, To prevent undue stress being produced by temperature changes.

4.7.2 Design factors

4.7.2.1 Service factor shall be in accordance with the latest AA Specification, Mechanical Standards (AA_SPEC_999022).

4.7.2.2 Where specific manufacturer or other requirements exist, these will be stated in the relevant equipment specification.

4.7.3 Transmissions

4.7.3.1 Chain drives (Not preferred)

4.7.3.2 Chain drives shall be in accordance with the latest AA Specification, Mechanical Standards (AA_SPEC_999022).

4.7.3.3 Chain drives shall not be specified unless application is essential to the satisfactory operation of the equipment.

4.7.3.4 V-Belt Drives (Not preferred)

4.7.3.5 V-belt drives shall be in accordance with the latest AA Specification, Mechanical Standards (AA_SPEC_999022).

4.7.3.6 Gearing

4.7.3.7 Gearing shall be in accordance with the latest AA Specification, Mechanical Standards (AA_SPEC_999022).

4.7.3.8 Speed reduction units shall be in accordance with the latest AA Specification,


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Mechanical Standards (AA_SPEC_999022).

4.7.4 Bearings

4.7.4.1 Bearings shall be in accordance with the latest AA Specification, Mechanical Standards (AA_SPEC_999022).

4.7.4.2 All bearings must be SKF with the exception for conveyors pulleys (only) where FAG may be used as an alternative where SKF bearings are not available.

4.7.4.3 The L10 life shall be calculated at the maximum speed and radial and axial loads resulting from rated motor power.

Mechanical Equipment Minimum L10 Life (hours)

Cranes, trolley and hoists (maintenance)

3,000 (Service Class below H3 only)

Gear drives – combination drives 60,000

Pumps 60,000

Agitators 80,000

Conveyor pulley plummer blocks 100,000

Conveyor idlers 40,000

Screens 80,000

Compressors, blowers, process fans

100,000

Table 7 – Minimum L-10 Bearing life

4.7.4.4 Plummer blocks shall be designed and installed such that the belt load acts through the mounting base. Stored energy within the conveyor belt must not result in an unsafe condition when the bearing cap is removed.

4.7.4.5 Greasing points shall be provided for all plummer blocks.

4.7.4.6 All electric motors used on VSD installation above 90 kW, must be equipped with insulated bearings at either the drive or non drive end to mitigate the effect of stray currents.

4.7.4.7 Bearing sole plates must be supplied loose for site welding to ensure that bearing housings can be aligned. Galvanising must be grinded off locally prior to site welding and repaired according to CPS41 A after installation.


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4.7.5 Brakes

4.7.5.1 Brakes are generally not required on conventional conveyors.

4.7.5.2 Brakes shall be in accordance with the latest AA Specification, Mechanical Standards (AA_SPEC_999022).

4.7.5.3 Where required, brakes shall be fitted to the high-speed input shaft of the speed reducers and on the reducer side of the coupling, fail safe, with automatic wear compensation, and adjustable brake torque.

4.7.5.4 Disc callipers shall be mounted on rigid supports attached to the same base frame as the drive.

4.7.5.5 Brake pivots shall be provided with self-lubricating bushings and hardened alloy steel pins on all pivoting joints.

4.7.5.6 Brake rated torques shall be at least 150 % of specified braking torque.

4.7.5.7 Brakes used on out-of-balance loads shall be capable of arresting the load in the event of a trip of the motor in the maximum out-of-balance condition.

4.7.5.8 The rated heat dissipation shall allow for the specified stops per hour without fade or loss in holding.

4.7.5.9 Brakes shall use asbestos-free shoes and pads.

4.7.6 Lubrication

4.7.6.1 Lubricants and lubrication shall be in accordance with the latest AA Specification, Mechanical Standards (AA_SPEC_999022).

4.7.6.2 All equipment which normally contains lubricant and is despatched without such lubricant shall have their interior sprayed with a suitable moisture inhibitor, to prevent corrosion during transport and storage. Such equipment shall carry clear legible tagging indicating that it does not contain lubricant. All machinery and equipment shall be checked for cleanliness and lubrication prior to testing or start-up.

4.7.6.3 As far as possible a centralised lubrication system shall be considered for multiple items of equipment supplied. Where a centralised lubrication system is not justified, multiple lubrication points in close proximity shall be plumbed to a central manifold block accessible without removing safe guards. Lubrication plumbing shall be neatly run and supported as required. Lubrication points shall be labelled to indicate the point supplied.

4.7.6.4 All oil lubricated equipment shall be provided with a valve at the outlet (where practical) so that samples for oil analysis may be easily taken.

4.7.6.5 First fill of lubricants shall be agreed by project team and included in the Capex or SIB costs.


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4.7.7 In-plant Maintenance Facilities

4.7.7.1 In designing or selecting the equipment, attention shall be given to the ease of operation and maintainability of the plant as well as operational costs.

4.7.7.2 The design and selection of equipment shall be directed towards minimizing maintenance and maintenance durations.

4.7.7.3 Steelwork, walkways, stairs, platforms, etc. must allow safe and adequate operational and maintenance access shall be provided.

4.7.7.4 Crawl beams, equipped with crawls but not lifting tackle, strategically placed so that all heavy lifts required to maintain the plant and equipment may be safely and easily carried out shall be provided.

4.7.7.5 Equipment must be arranged so that overhead crawl or lifting beams provide simple and adequate suspension for in situ stripping and/or removal to an external workshop.

4.7.7.6 Electrical overhead travelling cranes will be provided in the main plant and plant workshop. Cranes shall be in accordance with the latest BS 466 standard.

4.7.7.7 The plant crane will be sized to lift the heaviest piece of equipment within the crane’s reach.

4.7.7.8 Crawl beams will be fitted over equipment that is not accessible by the overhead crane including all transfer towers, bins and the discard silo.

4.7.7.9 Crawl beams will be fitted with manual trolleys.

4.7.7.10 Stop blocks will be fitted to both ends of the crawl beams.

4.7.7.11 The safe working load, SWL, must be stencilled onto both sides of crawl beam web after passing load test certification.

4.7.7.12 No lifts, including construction activities, shall take place on a new crawl beam prior to passing load test certification.

4.7.8 Cleaning operations

4.7.8.1 All floors in wet areas should be concrete and easily accessible for skid steer loaders (bobcat) without obstacles.

4.7.8.2 Skid steer loaders (bobcat) access is required around conveyor tail end areas and inside tunnels.

4.7.9 Dust suppression and extraction

4.7.9.1 All materials handling facilities will be designed to minimise, and where possible, to prevent the generation and liberation of dust.


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4.7.9.2 Methodologies will vary from passive e.g. tip dust hood and active systems e.g. water spray systems.

4.7.9.3 Ducted dust extraction systems and filters are not preferred. These may be used in limited quantities where required by an analysis of an experienced dust control specialist.

4.7.9.4 Water sprays will be used to suppress dust escaping from enclosures. Each water spray system will be designed for the optimised droplet size and velocity. The objective will be to balance the system requirements in terms of water consumption, maintainability, dust suppression efficiency, water quality requirements and simplicity.

4.7.9.5 Where fine droplet sizes are preferred, the spray systems will make use of suitable atomizing nozzles (using either by pneumatic or high pressure hydraulic methodologies). Water supply systems to atomising dust spray systems will include fine filtration and possibly reverse-osmosis treatment, as required by an analysis of the quality of the water supply system.

4.7.9.6 Water sprays, where used will be specified in a manner which avoids caking and build-up on materials handling equipment. Sprays must ideally be directed towards the conveyed material.

4.8 Fire protection

4.8.1.1 Fire suppression and detection to be provided in accordance with the latest Specifications:

AATC000168 Fire protection for buildings and structures

AATC000169 Fire protection for conveyors and coal transfer

4.8.1.2 Risk assessments will be required to finalise the project scope.

4.9 Pipework and Valves

4.9.1 General

4.9.1.1 Piping covered in this document specifically addresses plant related environments. Bulk supply and services to the plant are covered by civil engineering.

4.9.1.2 All piping systems, equipment and design shall comply with the latest relevant standards, regulations, codes and statutory requirements. (Refer to Reference Documents)

4.9.1.3 Piping systems shall be designed to facilitate reliable and continuous operation, as well as easy accessibility for operation, maintenance, equipment replacement, handling, cleaning and inspection.


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4.9.1.4 All pipe work, equipment and apparatus supplied and installed shall be designed to ensure satisfactory operation under the atmospheric, ambient and other conditions prevailing at the plant/site.

4.9.1.5 The Contractor shall ensure that all piping and components stored on site are placed on sleepers or pallets. All open ends of piping, valves and fittings shall be provided with plastic or wooden end caps to prevent ingress of dirt and other foreign matter.

4.9.2 Piping Categories

4.9.2.1 Piping is classified under the following categories:

General Purpose Slurries &

moderately acidic fluids

Alternate of aggressive

slurries

Fluids

Raw water, potable water, plant air, instrument air, air for the filter plant, flocculent, coagulant.

Clarified water, dilute medium, magnetite solutions, polluted water, effluents, correct medium

Correct medium distribution

Special Category

Spray bars in abrasive environments, gland seal water (GSW)

Pump suctions and other high wear items

Table 8 – Piping Categories

4.9.3 Design of Piping Systems

In designing a piping system the following design parameters shall apply:

4.9.3.1 All pipe and fittings supplied shall be new and unused.

4.9.3.2 Pipe routes shall be as short and straight as possible using 45° and 90° bends.

4.9.3.3 Consideration shall be given to the overall piping system behaviour under dynamic conditions. 90° bends do not lend itself to being self-draining; 85° are preferred.

4.9.3.4 Relevant pipe routes shall be self-draining. Drain valves shall be fitted on any pipelines which do not self drain, however this should be avoided. No “dead” legs are acceptable.

4.9.3.5 Pipe deliveries into sumps and tanks shall be directed away from the suction inlet to avoid air entrainment, instrumentation and towards the centre of the sump or tank to minimise wear and vortex generation.

4.9.3.6 Flushing points shall be provided to assist drainage and cleaning where necessary.

4.9.3.7 The number of connectors shall be minimised wherever possible. However the


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following opposing factors shall be considered: handling of pipe sections in confined spaces, application of corrosion protection linings to bends, future extensions or branches to the pipeline and the need for closer sections. Sacrificial spools, approximately 1000 mm long shall be installed on the downstream side of bends.

4.9.3.8 Pipe routes shall not interfere with walkways or maintenance access. Where pipes are routed over walkways a minimum of 2300 mm headroom is required under the lowest obstacle. For example the lower edge of a flange or the lowest edges of a pipe support.

4.9.3.9 Valves and instrumentation shall be located in readily accessible positions for operation and maintenance. Special platforms must be provided if necessary.

4.9.3.10 Water and air piping up to 50 NB shall have threaded connections with sufficient number of unions for easy replacement of valves, instruments etc. and shall be hot dipped galvanised.

4.9.3.11 Water and air piping larger than 50 NB shall be a combination of flanged and butt welded construction and shall be hot dipped galvanised.

4.9.3.12 Flanges shall be to the latest SANS Specification, Pipe flanges (SANS 1123). Flanges shall be table 1000/3 flat face except for tailings lines or any other medium or high pressure line which shall be rated to the required design pressure.

4.9.3.13 In flanged pipe runs, flanges are to be provided at all changes in direction and all pipework is to be in reasonably lengths for ease of handling and maintenance. The maximum distance between flanges shall be 6m for in-plant piping and 18m on tailings lines. All flanges shall be accessible as far as possible and positioned ±1,0 m above the floors.

4.9.3.14 Piping will be designed with adequate flexibility for thermal expansion and where required be analysed to ensure compliance with the applicable code(s). Either expansion loops or expansion joints shall address thermal expansion and contraction.

4.9.3.15 Standard lengths of pipes and fittings should be used where possible.

4.9.3.16 Pipe supports and hangers shall comply with the latest requirements of BS 3974. Attention shall be given to the support system in order that external loads acting on pump suctions, discharge nozzles and branches may be minimized. Expansion/compression on HDPE lines shall be taken into consideration.

4.9.3.17 Wear resistant pipes or lining to be used with abrasive fluids.

4.9.3.18 Suctions on slurry pumps to be lined with 25 or 13 mm hi-alumina tiles and or 6 mm epoxy all as per requirements outlined under item 4.10.9, Lining philosophy.

4.9.3.19 Abrasive and non-abrasive pump suctions to have eccentric reducers (flat top), drain and flush valves and tapered breakout piece. The reducer shall be designed to suit the flow requirements.

4.9.3.20 300 NB and larger process and clean water pump suctions and discharges will not be fitted with flexible Bellows.


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4.9.3.21 Axial bellows units shall comply with the requirements of the Expansion Joint Manufacturers Association (USA). Further guidance on the design and specification of bellows and bellows installation is detailed the latest British Standard, Code of practice for the selection and application of bellows expansion joints for use in pressure systems.

4.9.4 Line Sizing

4.9.4.1 Line sizing shall be calculated considering the effects of friction drop, erosion, solids settling, product degradation, water hammer, NPSHr, process flow variations, provision for future capacity increases. The following velocity ranges are a guide:

Fluid Type Pipe Velocity Guide m/s DN50 to DN100

DN150 to DN250

DN300 to DN400 DN450 to DN750

Min Max Min Max Min Max Min Max

Liquids

Pump Suction 0,6 0,9 1,2 1,6 1,3 1,7 1,8 2,3

Pump Discharge

1,2 2 2,1 2,4 2,5 3,1 3,2 4,6

Pump Discharge flocculent

1,2 1,5 1,8 2

Pump suction & discharge-organic

1,0 1,0 1,0 1,0

Pump discharge – fuel/lube oil

0,5 1,0 0,5 1,0 0,5 1,0 0,5 1,0

Gravity 1,0 1,0 1,0 1,0

Slurries

Pump Suction 1,2 1,4 1,2 1,5 1,3 1,7 1,8 2,3

Pump Discharge

1,5 1,6 1,8 2,4 2,0 3 2,6 3,8

Gravity-non settling

1,0 1,0 1,0 1,0

Gravity-settling slurry

Settling velocity + 15%

Table 9 – Pipe velocity guide

4.9.4.2 The above guide is not applicable for two phase flow or pressure relief lines.


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4.9.5 HDPE Pipes and Fitting

4.9.5.1 For all slurry applications HDPE pipes to comply with the latest SANS Specification, Polyethylene (PE) pipes for water supply (SANS 4427). The nominal pressure rating shall be PN 6 or higher if pressure dictates.

4.9.5.2 HDPE slurry piping shall be flanged throughout or a combination of fusion welds and flanges, depending on the system length and duty.

4.9.5.3 All fittings are to be fabricated from HDPE pipe.

4.9.5.4 All fittings to be provided with weld on stub-ends and backing rings on both sides. Backing rings to latest SANS Specification, Pipe flanges (SANS 1123), table 1000/ 3 and hot dip galvanized.

4.9.5.5 Maximum pipe lengths to be 9 meters. Shorter lengths shall be used as necessary inside buildings for installation purposes.

4.9.5.6 Correct Medium feed box and HM cyclone feed piping will be Basalt lined.

4.9.5.7 HDPE pipe bends to be seamless and pulled to have a radius of minimum 3D for all slurry lines.

4.9.5.8 Bends to be standardized with regard to bend degrees and centre to face dimensions.

4.9.5.9 Fittings and pipes which have misalignment on welded joints due to ovality will not be accepted.

4.9.5.10 Welding of HDPE joints shall conform to the Manufacturer’s procedures.

4.9.6 Steel Pipes

4.9.6.1 150NB and below to be mild steel to the latest SANS Specification, Steel pipes: Part 1, Pipes suitable for threading and of nominal size not exceeding 150mm. Pipes shall be heavy wall hot dip galvanized.

4.9.6.2 Pipe 200NB and above to be mild steel to the latest SANS Specification, Electric welded low carbon steel pipes for aqueous fluids (large bore). Pipes shall be grade "A", 6mm thick wall hot dip galvanized.

4.9.6.3 Steel pipe bends shall have a radius equal to 1 ½ x nominal bore (i.e. long radius) and constructed to steel pipes material specification.

4.9.6.4 Lined pipes are painted on the outside as per specifications.

4.9.6.5 Pump suctions to be mild steel as per the above relevant SANS Specifications and coated as per the latest Anglo American corrosion prevention specification.

4.9.6.6 Maximum working pressures:


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Slurry 650 kPa Raw, process or gland service water 1000 kPa Compressed air 1000 kPa Tails lines As per Engineer’s design Spray water pipes Rated to run @ 450 kPa Wedged blank flanges Knock-off flanges to be installed on

selected tanks, sumps and platework to provide instant emergency drainage

Table 10 – Maximum Working Pressures

4.9.7 Compressed air pipework

4.9.7.1 Compressed air piping and distribution headers will be galvanised and provided with suitable filter/lubricator sets, air pressure gauge, isolating valve and water drainage valve. Headers will be installed at approximately 5 ° to the horizontal for water collection and drainage.

4.9.7.2 Compressed air and instrument airlines shall be sized so the pressure at the end of the most resistant branch line does not drop below minimum requirements with full flow in that line

4.9.7.3 Compressed air and instrument air branches shall be taken off the top of the respective header.

4.9.7.4 Compressed air systems shall have a moisture trap at the low point in the air system for each major plant area.

4.9.8 Spray bars in abrasive environments and gland seal water (GSW)

4.9.8.1 Schedule pipe to ASTM A106 Gr.B and pipe fittings to BS 3799 screwed to BS 21 ISO R7 and EN10226-1, are to be used for spray bars below 50 NB. All items are to be hot dip galvanised to ISO 1461 Heavy duty.

4.9.8.2 In the event of GSW pipework having an operating pressure in excess of 600kPa (two stage pumping) then schedule pipe and fittings to BS EN 10241 shall be used.

4.9.8.3 Single stage pumps will have GSW fabricated to ‘General Purpose Pipework’ specification.

4.9.9 Slurry pipes

4.9.9.1 Slurry pipes are to be routed as directly as possible, with the minimum, least angled bends possible. Head box nozzle orientations shall where possible aid in the elimination of pipe bends.


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4.9.9.2 Slurry pipes shall be routed in such a way that self drainage will occur. Dead legs may only be installed when there is no alternative. In such cases a drain valve must be installed at the lowest point.

4.9.9.3 Slurry piping shall be arranged and supported to facilitate dismantling, flushing and descaling. Straight lines shall be flanged to permit rotation and bends should be flanged to permit replacement. Pipes shall be self-draining, preferably back to a tank or vessel. Where this is not practical, provision shall be made for dumping the slurry at low points.

4.9.9.4 The process engineer shall advise the minimum allowable angle for slurry, which will normally be between ten and twenty degrees fall from the horizontal.

4.9.9.5 Selection of pipe sizes for slurry service shall ensure that line velocities are kept above solids settling velocities.

4.9.9.6 Steel slurry pipelines (including rubber-lined) shall be flanged at every fitting and branch.

4.9.9.7 Slurry lines shall have a maximum flanged length of 6 m within the process plant and a maximum length of 9 m outside of process plant areas. Rubber lined slurry lines shall have a maximum flange length of 6 m for all process applications.

4.9.9.8 The first pipe spool immediately after the pump discharge reducer shall be a minimum of three meters long to reduce wear created by the pump discharge velocity and turbulence.

4.9.9.9 Sacrificial spools, approximately 1000 mm long shall be installed on the downstream side of bends.

4.9.9.10 Long radius swept bends shall be utilised for all slurry piping. No ‘lobster back’ bends shall be permitted.

4.9.9.11 Flushing water and drain connections will be provided at pump boxes and sumps and at vertical piping as required.

4.9.9.12 Pipes shall be either rubber lined, materials handling hose or high-density polyethylene or similar as per the piping specification and P&ID’s.

4.9.9.13 Slurry pump suction lines shall reduce according to the requirements of the P&ID’s. Reductions shall be made with eccentric reducers with the bottom flat.

4.9.9.14 Slurry pump suction lines will be kept as short as practically possible.

4.9.10 Pump Suction Lines

4.9.10.1 Pump suction lines shall be short and shall not be smaller in diameter than the pump nozzle.

4.9.10.2 Any reduction in diameter shall be made gradually through a tapered eccentric reducer


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with the flat on top; except for slurry lines where the flat shall be on the bottom.

4.9.10.3 Elbows or bends shall not be placed within 4 pipe diameters of the pump suction nozzle.

4.9.10.4 Isolating valves are to be accessible and in the case of Knife Gate Valves, are to be orientated with the hand wheel or actuator as vertical as possible.

4.9.10.5 Drain valves must drain the suction completely.

4.9.10.6 Pump suctions smaller than 300 NB shall be installed with a bellows.

4.9.10.7 Pumps shall be mounted on an integral pump support frame designed to enable pump alignment and pump drawback to facilitate removal of suction piping and pump internals replacement.

4.9.10.8 Pump suctions will be designed to allow for ease of maintenance of the pump

4.9.10.9 Steel Pipes Bends – (Water & Air Lines) to have radius equal to 1½ x nominal bore (i.e. long radius) and constructed to steel pipes material specification.

4.9.10.10 Bends in high wear regions to have a minimum radius of 5 x diameter.

4.9.10.11 The ratio of the mean bend radius to the outer diameter of the pipe shall be not less than 2. Bends in unlined steel pumped lines > 80 NB and in gravity lines where the vertical fall before the bend is greater than 3 metre shall be white cast iron complying with the latest British Standard, Founding. Abrasion resistant cast irons.

4.9.11 Threaded steel pipes

4.9.11.1 Small bore screwed fittings 50 NB and below shall comply with BS 21 ISO R7 and EN 10226. Lines 50 mm and below will be threaded instead of flanged.

4.9.11.2 Threaded pipes and all the fittings to be hot dipped galvanised.

4.9.11.3 Small bore 50 NB and below service pipelines may be site run with screwed connections having at least one union every two changes of direction. The route for such pipelines shall be indicated on drawings and shall be approved by the Engineer.

4.9.11.4 Threaded joints may be made with suitable tape or sealing compound, except where fragments of tape may block down stream equipment, e.g. fine spray nozzles, and joints to be seal welded.

4.9.12 Steel pipe flanges

4.9.12.1 Flanges to be mild steel HD galvanized, flat face, drilled off-centre (two holes top) to the latest SANS Specification, Pipe flanges. The flanges shall be table 1000-3 as specified, continuously welded to pipe, both internal and external.


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4.9.13 Fittings and gaskets

4.9.13.1 Fittings 65/80 NB up to and including 150 NB to be butt-weld fittings to BS 1640 AND BS EN 10253-2 Schedule 40 and ANSI B16.9

4.9.13.2 Fittings 200 NB and above to ANSI B16.9 or fabricated from pipe.

4.9.13.3 Threaded wrought steel fittings to be to BS EN 10241.

4.9.13.4 Screwing to ISO/R7.

4.9.13.5 Gaskets to be 3 mm thick, klinkerite or equivalent. No asbestos permitted.

4.9.13.6 Full face gaskets shall be used on flat face flanges, ring type gaskets shall be used on raised face flanges. For high pressure steel pipelines gaskets shall be spiral wound metallic to the latest British Standard, Specification for spiral wound gaskets for steel flanges.

4.9.14 Slurry rubber hoses

4.9.14.1 Heavy duty slurry rubber hoses shall be constructed with double layer of spring wire, nylon fabric and 9 mm or 11 mm thick hard liner with a pressure rating 700 kPa.

4.9.14.2 Minimum radius of hose bends shall be 10D. For splitter boxes where hoses are used to divert flow, the hose will be constructed without spring wire.

4.9.15 Closures

4.9.15.1 To be supplied 150 mm longer than installed length.

4.9.15.2 Flanges on stubs to be left loose and welded during erection.

4.9.16 Marking

4.9.16.1 All items to be clearly marked on pipes approximately 300 mm from fixed flange with line number and item number. Rubber hoses to be securely tagged with item and line number.

4.9.17 Colour Coding

4.9.17.1 All plant piping shall be colour coded in accordance with the latest Anglo American Specification AA_Spec_164051_Plant colour coding


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4.9.18 Fasteners

4.9.18.1 All pipe bolts, nuts and washers to be SANS 1700 Class 4.8 hot dip galvanised and suitably bagged, labelled and dispatched to site together with pipes.

4.9.18.2 High pressure piping with flanges table 25/3 or higher to be bolted with Class 8.8 hot dip galvanized fasteners.

4.9.19 Stainless Steel

4.9.19.1 Stainless Steel Pipe and fittings shall be to ANSI 316L.

4.9.20 Nozzles

4.9.20.1 To conform to pipework fabrication and platework lining requirements.

4.9.21 Supports

4.9.21.1 Pipe support to the requirements of BS 3974

4.9.21.2 This will generally take the form of U-bolts and angle or channel-iron brackets and supports welded to the adjacent building steelwork during and after completion of pipe installation. HDPE piping of 75 O.D. or smaller shall be provided with continuous supports.

4.9.21.3 All pipe supports and U-bolts to be hot dip galvanized.

4.9.21.4 Galvanized steel structure surfaces damaged due to welding of the supports shall be repaired as per the Anglo American procedure CPS 41A.

4.9.21.5 Pipelines shall be adequately anchored to withstand the reactions caused by changes in pipe direction, temperatures, pressure, etc. Pipes connected to a fixed item of equipment shall be anchored in such a way that no thrust forces are imposed on the item to be connected.

4.9.22 Valves

4.9.22.1 Valves shall comply with the latest Anglo American Specification – (General purpose valves).

4.9.22.2 Valves shall be selected for the specific duty, rating and operation required.

4.9.22.3 In order to ensure a “fit for purpose” the expertise of the valve supplier must be sought


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and coupled with past experience gained from similar applications.

4.9.22.4 Information required, but not limited to for valve selection:

Maximum differential working pressure Full details of medium to be carried including corrosiveness, abrasion, particulate

matter, line transport velocity and volume of flow. Environmental conditions Duty, e.g. isolation, regulating pressure control, together with closure time required. Type of control, i.e. manual, automatic (local or remote) and any limitations of

access Limitations of space for determining gearbox/actuator/handwheel orientation Flange table Line position

4.9.22.5 Valves and instrumentation shall be located in readily accessible positions for operation

and maintenance. Access platforms shall be provided where necessary.

4.9.23 Lifting lugs

4.9.23.1 Large pipe fittings which are removable for valve and pump servicing shall have designed lifting lugs welded to them.

4.9.23.2 Where heavy equipment are furnished with lifting lugs for installation and maintenance the following requirements shall apply:

Lifting lugs shall be:

Positioned to give maximum balance with an even weight distribution where possible to minimize handling hazards.

Designed to have a safe working load of at least six times the design load suspended by it.

Manufactured in accordance with drawings which have been approved by a Professional Engineer.

Designed for use with standard shackles, Grade S. Shown on drawings together with slinging details and load weight. Special

attention shall be given to lifts using more than three lugs to ensure proper load distribution. Unequal sling and lug loads caused by differences in nominally equal sling lengths and sling stacking arrangements on hooks shall be avoided.

Permanently fixed to all items requiring removal for inspection and maintenance.

4.9.23.3 For fabricated lifting lugs all welds shall be examined by NDT. Acceptance criteria shall be in accordance with the registered Engineers approved design requirements.

4.9.23.4 The maximum allowable sling angle from the vertical shall be determined and marked at all lifting points.

4.9.23.5 Removable lugs shall be bolted to each component in the shop prior to shipment and


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remain attached until erection work is completed.

4.10 Platework and Lining

4.10.1 General plate work requirements

All platework required to control and direct material, prevent spillage, contain fluids, etc. shall be included in the scope of the contract and shall comply with the following general requirements:

4.10.1.1 Platework shall be fabricated from steel plate complying with S355JR or while availability permits, SABS 1431, grade 300WA, no less than 6 mm thick. 3CR12 may be considered in specific applications where approved by the Engineer.

4.10.1.2 Fabrication and erection shall be in accordance with AA Specification 114/2.

4.10.1.3 All welds shall be in accordance with AWS D1.1, shall be 6mm continuous fillet welds, and shall be watertight.

4.10.1.4 Flanges and stiffeners shall be a minimum 65 x 6 thick flat bar.

4.10.1.5 Boltholes shall be 18 mm diameter for M16, Class 4.8 bolts, spaced at a maximum pitch of 200 mm.

4.10.1.6 Joints shall be watertight.

4.10.1.7 Chute support brackets shall be fabricated from 10 thick plate and shall be drilled to 22 mm diameter holes for M20 Class 4.8 bolts.

4.10.1.8 Precautions shall be taken to prevent platework from distorting during transport and erection. Platework and support steelwork shall not be put under strain in order to erect the platework.

4.10.1.9 All nuts, bolts and washers shall be hot dipped galvanised.

4.10.1.10 In designing plate work, care must be taken to avoid dead boxes where water and fugitive material can be trapped. Large cut-outs must be provided to allow drainage.

4.10.1.11 Corrosion protection shall be in accordance with AAC Specification 164/50 and the following:

All new platework shall be painted on the outside in accordance with CPS 132. Internal surfaces shall be prime painted after drilling and before liners are fitted. The outside finish colour shall be Aircraft Grey Green (SABS 1091 D18).

4.10.1.12 Impact onto any platework shall be avoided (and high impact is unacceptable), but where it cannot be entirely eliminated a suitable design shall be submitted to the Engineer for an approval.

4.10.1.13 Internal surfaces below steel liners will be prime painted only.


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4.10.2 Platework subjected to normal impact and slide loading:

4.10.2.1 Minimum 8 mm thick plate with 10 mm support brackets, 80 x 8 minimum flanges and stiffeners to SANS 1431-Grade S355JR designed to minimize plate deflections.

4.10.2.2 Platework shall be suitably stiffened when ceramic lining is required. The philosophy is to use a thick plate with fewer stiffeners as opposed to an over stiffened thin plate.

4.10.3 Welding

4.10.3.1 Plate joints to be 6 mm (leg length) continuous fillets on both sides, unless otherwise specified by the design engineer.

4.10.3.2 External stiffeners shall have a full 2 mm seal weld to prevent ingress of moisture. Stitch welding to achieve the required structural strength is permitted.

4.10.4 Plate Packs

4.10.4.1 Where required to be laminated and wired to platework item for delivery.

4.10.4.2 Packs shall not exceed 30 mm.

4.10.4.3 On final assembly a single packer made to final dimension is preferred.

4.10.5 Joints

4.10.5.1 To be sealed with compri band strips on the full flange width where faces are not rubber lined.

4.10.6 Fasteners

4.10.6.1 For platework, bolts, nuts and flat washers to conform to SANS 1700 Class 4.8 and to be hot dipped galvanised.

4.10.6.2 Bolts on chutes where high impact is anticipated to be secured with Nylock, Cleveloc or Huck fasteners. Electro plated galvanised bolts are permitted on these applications.

4.10.6.3 Taper washers to be fitted to steel sections with taper flanges.

4.10.6.4 Site bolts to be suitably bagged, labelled and wired to platework item for delivery.

4.10.6.5 Nylock nuts shall not to be used where burning coal is anticipated.


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4.10.7 Marking

4.10.7.1 All items to be hand stamped (min. size 12 mm) with drawing and item number. Hand stamps shall be clearly visible after hot dip galvanising.

4.10.8 Painting

4.10.8.1 External and Internal: Refer to Corrosion Protection under section 5.6.

4.10.9 Lining Philosophy

General materials handling applications:

4.10.9.1 A project specific liner schedule must be developed for approval by the Engineer.

4.10.9.2 The life of mine, accessibility and standardisation of liners shall be considered when selecting liners.

4.10.9.3 All surfaces that may be subject to wear shall be lined with a wear resistant material suited to the nature of the wear, i.e. high impact or sliding. Where particle size of up to 50 mm is encountered, 25 mm ceramic hi-aluminium tiles on impact faces and 13 mm tiles on sliding faces is considered the minimum.

4.10.9.4 Platework handling material where the particle size exceeds 50 mm, replaceable 400 Brinell liners must be used with minimum thickness of 12 mm on the sides, 25 mm thick on the impact faces.

4.10.9.5 Although 500 Brinell liners are also commonly used, new projects should be designed with 400 Brinell liners. Where higher wear occurs, the operation may do liner replacements in these regions (only) with the higher specification.

4.10.9.6 Where extreme excessive wear is anticipated, special wear liners is to be considered.

4.10.9.7 Cast in rails shall be used for tip jockey slabs and concrete tip bins.

4.10.9.8 Specific consideration must be given to ROM and Raw Coal systems from previously undermined open cast operations.

4.10.9.9 Lining will be carried out in the workshop and/or on site depending on the size of the item and the assessed risk of damage during transport and erection.

4.10.9.10 Mass of any liner to be limited to 25 kg each and secured with 4 nibhead countersunk bolts, nylock or cleveloc nuts and washers (i.e. retained torque nuts). When determining the mass of liners consideration shall be given to wastage, sizing and maintenance.


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Plant Applications:

4.10.9.11 Very high wear wet abrasive areas such as HM cyclones under flow boxes (impact face) to be lined with 50 mm hi-aluminium tiles.

4.10.9.12 High wear wet abrasive areas containing raw materials (coals and discards) and magnetite will be lined with 25 mm thick hi-alumina tiles, e.g. cyclone mixing boxes, floats and sinks boxes as indicated on the drawings.

4.10.9.13 Wet abrasive areas containing coal water slurries or magnetite/coal suspensions will be lined with 13 mm thick hi-alumina tiles, e.g. screen underpans, head boxes, magnetic separator underpans and the conical portions of all process tanks (including outlet nozzles). Split tiles.

4.10.9.14 Wet areas of relatively low abrasion will be lined with 6 mm thick hi-alumina epoxy, e.g. vertical tank sides, tailings launders, etc.

4.10.9.15 Areas above hi-alumina tiles or epoxy will be lined with 1 mm thick brushable wearing compound. Edge smoothing must be done.

4.10.9.16 Platework for “wet and sticky” fine material will be lined with minimum 8 mm thick solidur or equivalent, e.g. fine coal centrifuge feed and discharge chutes, dewatering screen discharge and conveyor dribbling chutes where material hang-ups could occur.

4.10.9.17 Drop boxes shall be used on certain platework items such as cyclone overflow and underflow collection, distribution or feed boxes to prevent direct flow of the slurry against the ceramic lined surfaces if practical. At the same time, the possibility of blockages shall be considered.

4.10.10 Lining Specifications

4.10.10.1 Ceramic tiling application method, unless otherwise specified by liner supplier:

a) Preparation of substrate:

Steel surfaces shall be shot-blasted to SA 2½, 50 - 75 microns profile

b) Laying of tiles:

Lay the tiles that joints are offset in direction of flow wherever practical. Tile length shall be perpendicular to the main stream flow.

c) Gaps and Steps

Gaps between tiles in excess of 3 mm are not permissible. Steps in excess of 3 mm are not permissible if against the flow. Tiles must be overlayed in direction of flow only. Tiles must overlap in corners


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4.10.10.2 Steel Lining

4.10.10.3 All steel liners to be 400 Brinell (minimum tensile strength 1340 MPa) or equivalent. Also refer to 4.10.9.5 and 4.10.9.6

4.10.10.4 Standardised liner size and shapes must be used where possible.

4.10.10.5 Liners to be brick patterned in the material flow direction.

4.10.10.6 Gaps between steel liner plates not to exceed:

3 mm for up to including 16 mm thick liners 5 mm above 16 mm thick liners 8 mm for 50mm thick liners

4.10.10.7 For all steel liners, bolts are to be accessible from the outside of the chute or bin.

4.10.10.8 Liner plates are to be fastened by means of counter sunk nib bolts.

4.10.10.9 Fastening holes in liners must be drilled such that only 3 mm of liner thickness below the counter sunk bolt head remains to ensure the maximum liner life.

4.10.10.10 UHMWPE Lining

4.10.10.11 All UHMWPE lining to be Solidur/TIVAR 88 or approved equivalent.


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5 STRUCTURAL DESIGN CRITERIA

5.1 Plant Buildings and Structures

5.1.1 General

5.1.1.1 Design of structural steelwork shall comply with the latest Anglo American Specifications – AA_SPEC_114/01 (Design of steel structures) and AA_SPEC_114/02 (Construction of structural steelwork)

5.1.1.2 AA_SPEC_114/01 requires that the latest versions of normative reference documents are used. AATC nevertheless has a conditional concession to continue using the SABS 0160-1989, (amended 1993) loading code until the end of 2017.

5.1.1.3 When designing support structures for major equipment such as jaw crushers, rotary breakers, screens, hydraulic rock breaker, apron feeder etc. the structural designer shall initiate a clarification meeting with the OEM to ensure that certified equipment loads, and the operation of the equipment is fully understood.

5.1.1.4 When designing crawl beams, it is acceptable to use BS2853:1957 for flange cross bending calculations.

5.1.1.5 All steelwork shall comply with the following general requirements:-

All welds shall be in accordance with AWS D1.1 and shall be 6 mm continuous fillet welds, unless otherwise specified by the design engineer.

All holes in structural members shall be 22 mm diameter for M20, Class 8.8 hot dipped galvanised bolts unless otherwise specified by the design engineer.

Holes in lightly loaded components, e.g. purlins, girts, handrail fixings, ladders, etc., shall be 18 mm diameter for M16 grade 4.6 hot dipped galvanised bolts.

Care must be taken to orientate structural members toe down to avoid dead boxes where water and material can be trapped.

Stiffeners on column bases must be positioned to avoid dead boxes. Where pockets do occur, it needs to be filled with concrete and a non-shrink epoxy grout.

The use of high strength galvanized fasteners i.e. Class 10.9 and above, should be avoided as far as possible.

The use of electroplated bolts is not permitted.

All bracing end connections must have a minimum of two bolts per connection.

Before fabrication of steelwork may commence the designs and drawings shall be submitted to the Engineer for comment. This requirement shall in no way relieve the Contractor of nor diminish his responsibility for the correctness and functionality of the steelwork.


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5.2 Conveyor Structures

5.2.1 General

5.2.1.1 All structures shall be designed for 100 % belt loading. The ultimate strength of the structure must be validated for flooded belt conditions which will be treated as an emergency load case. Serviceability requirements may be disregarded for this condition.

5.2.1.2 The conveyor head frame shall be designed to withstand the forces imposed on it by the conveyor under all operational conditions. The head frame shall be free standing and shall not transmit any forces into the conveyor gantries. The head frame support steelwork shall be designed to withstand the maximum head frame load.

5.2.1.3 The drive and take-up sections may be incorporated into elevated gantries provided the gantry is designed to withstand the forces imposed on it.

5.2.1.4 Wherever a conveyor is elevated to the extent that maintenance or inspection will be difficult or impossible from ground level, elevated or gantry sections with inspection and maintenance walkways shall be provided. The elevated section shall adequately support both the carrying and return strands of the conveyor belt. Idlers and idler spacing on the elevated section shall be as for the run of conveyors section.

5.2.1.5 The elevated sections at the head end of conveyors shall be designed to tie-in with the head frame, without transmitting or receiving any forces from the head frame.

5.2.1.6 Holes for pig tails to support a pull wire cable shall be provided on both sides of the conveyor.

5.2.1.7 No deck plates to be used at any section of the conveyors, spilt material may burn spontaneously.

5.2.1.8 Approximately 150 mm clearance between belt and structures are required.

5.2.1.9 Heavy duty conveyor modules and civil foundations must be considered at chute discharge or material impact regions.

5.2.2 Gantries

For walkway requirements, refer to Section 5.3 – Walkways, access, platforms and flooring.

For sheeting requirements, refer to Section 5.4 – Cladding of structures

5.2.2.1 Environmental gantries

Galvanized non-slip (vastrap) floor plates are permitted on horizontal sections and on slopes of up to 5°

Floors must be water tight.


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Suspended conveyors stringers are preferred.

36 m long span gantries are preferred where a considerable distance of environmentally sensitive area must be crossed.

Constructability and crane access must specifically be considered.

5.2.2.2 Open gantries is generally used on all conveyor structures unless a specific need exist to use a box type gantry.

5.2.2.3 Box gantries must be considered on conveyors significantly elevated above ground level or where the use can be motivated.

5.2.2.4 Vehicle underpasses – Gantries inclined below 5° may be equipped with vastrap flooring. Solid concrete decks must be provided above underpasses where the conveyor inclination exceeds 5°. Provision must be made for wash down.

5.2.2.5 General gantry requirements

Gantries are to have welded side panels and bolted top and bottom lacing to suit transport limitations.

Standard 12, 18, 24 and 36 meter gantries must be used wherever possible taking cognisance of project standardisation.

Where substantial additional loads e.g. piping, cabling etc must be carried by a gantry, the design must specifically cater for these. Minor loads such as a 50 mm diameter pipe or small cabling may be disregarded subject to the discretion of the designer.

Gantry support legs shall be mounted with slotted hole connections in stool base plates for ease of erection.

5.3 Walkways, access, platforms and flooring

5.3.1 General

5.3.1.1 All landings, stair treads, walkways and handrails shall be in accordance to the latest Anglo American Specification: Design, Fabrication, Installation and Maintenance of open grid grating for floors, stairways and hand railing (ACSA_SPEC_114012).

5.3.1.2 Conveyors 900 mm wide or smaller shall have a single walkway 900 mm wide where the belt line is elevated more than 1.5 m above ground level.

5.3.1.3 Conveyors wider than 900 mm shall have double-sided walkway access, 750 mm and 900 mm wide at main access side where the belt line is elevated more than 1.5 m above ground level.

5.3.1.4 A sufficient clearance (400 mm minimum on wide walkway side) must be provided in


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area of take-up pulleys where the pulley guards restrict the walkway width.

5.3.1.5 Maintenance access must be provided to crawls, take-up towers etc. A 600 mm wide stair case and 750 mm wide platform will suffice unless the risk assessment dictates otherwise.

5.3.1.6 No cat ladders are permitted whatsoever.

5.3.1.7 Refer to 4.5.28 and 4.5.29 for guarding and conveyor underbelt guard requirements.

5.4 Cladding of structures

5.4.1 General

Plant structures will be provided with sheeting to the following guideline:

5.4.1.1 All coal handling and plant structures shall be sheeted from the 1st floor level up to allow easy access.

5.4.1.2 Water treatment plant structures must however be fully sheeted.

5.4.1.3 For SIB projects, the sheeting philosophy of the existing operation must be taken into consideration.

5.4.1.4 It is mandatory to utilise natural lighting wherever practical. The guideline is to allow for approximately 25 % to 30 % of the floor area in translucent side sheeting per floor level.

5.4.1.5 No translucent sheeting is permitted on roof sheeting.

5.4.1.6 At fixture points, translucent sheeting must be sandwiched between 100 mm backing strips cut from steel sheets to ensure durability.

5.4.1.7 Corrosion on hinged doors of old plants is problematic. The philosophy is to overdesign door hinges by applying an impact factor of no less than 5 to ensure long term structural integrity. Door frames and support steel need not be overdesigned although special attention must be given to the attachment interface between hinges, door frames and support steel.

5.4.1.8 All sheeting to be IBR profile, Chromadek pre-painted galvanised steel sheet or approved equivalent.

5.4.1.9 ZincAlume or Chromadek Plus or equivalent may be considered for extremely corrosive environments or where the project design life exceeds 30 years.

5.4.1.10 Regrettably no corporate specification is currently available. Good industry practice must be followed.

5.4.1.11 On SIB projects, the colour of sheeting must match that of existing structures.


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5.4.1.12 Sheeting colour for new projects must be confirmed by environmental impact studies. The following colour schemes are nevertheless standard within AATC:

Outside Inside

Option 1 Aloe Green (close

match to D18) Sandstone Beige,

C59

Option 2 Gemsbok Sand Dove Grey, G22

Table 2 – Sheeting Colours

5.4.1.13 Sheeting thickness standards are shown below:

Application Roof sheeting (mm) Side sheeting (mm)

Main plant structures 0.8 0.6

Conveyor transfer structures

0.8 0.6

All conveyors including overlands

0.6 0.6 (gantry walk

ways) Pedestrian underpasses

0.8 0.6 (where applicable)

Table 3 – Sheeting Thicknesses

5.4.2 Main plant structure

5.4.2.1 Roof and side sheeting must be reversed lapped. A full length gap must be provided between the roof and the side sheeting to ensure a natural draft.

5.4.2.2 Ridge ventilators and louvers must be provided in line with the recommendations of a sheeting specialist.

5.4.2.3 Plant structures housing large screens must specifically designed taking cognisance of pressure pulsation phenomenon associated with big screens.

5.4.3 Conveyor gantries

5.4.3.1 To eliminate a natural draft and propagation of fire, approximately 30 % of the sides must be left un-sheeted. Translucent sheeting is therefore generally not required on environmental and boxed gantries.

5.4.3.2 Open gantries must be equipped with doghouse type roof sheeting which allows access to idlers. Walkways must be side sheeted on the outside. Where wide cable racks are affixed to the outside of handrails, side sheeting must be omitted on that specific side only.


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5.4.4 Conveyors

5.4.4.1 Doghouse type sheeting must be installed on all conveyors such that the conveyed material is shielded from the prevailing wind direction. Doghouse sheeting must allow access from the enclosed side such that the sheeting line is terminated approximately in the middle of the wing roll.

5.4.4.2 In close proximity of dwellings, it may be required to enclose the entire conveyor.

5.4.5 Pedestrians crossings

5.4.5.1 0.8 mm IBR sheeting protection will be installed at all areas where “fall of material” could occur.

5.4.5.2 Dedicated pedestrian underpasses, integrated with the civil infrastructures designs, are required beneath conveyors.

5.5 Civil

5.5.1 General

5.5.1.1 Design of civil works shall comply with the latest Anglo American Specifications – AA114/10 (Design of concrete structures) and AA114/11 (Construction of concrete work)

5.5.1.2 Kerbs around buildings must be a minimum of 450 mm away from the sheeting perimeter.

5.5.1.3 Column bases in processing buildings must be 1000 to 2000 mm above floor level. 5.5.1.4 The floor level must be elevated no less than 200 mm above the normal ground level. 5.5.1.5 The minimum kerb height around buildings and structures should be 200 mm above the

floor level and no less than 150 mm thick. 5.5.1.6 Drainage slopes of 1:75 are required within buildings. 5.5.1.7 Drainage soil slopes of at least 1:50 are required. 5.5.1.8 Trestle plinths must be elevated by 1000 mm above the natural ground level. 5.5.1.9 Where vehicle access bays or pass through are provided in plants or next to trestles,

plinths must be raised to 2000 mm. 5.5.1.10 Stockpile tunnels, tip areas etc. must be free draining.

5.6 Corrosion Protection

5.6.1 General

5.6.1.1 All corrosion protection systems to be in accordance with the latest Anglo American Specifications, AA_SPEC_164000, Users guide for corrosion prevention and AA_SPEC_164050, System selection and Corrosion Protection of Steelwork with


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Coatings.

5.6.1.2 Colour coding shall comply with the latest Anglo American Specification, AA_SPEC_164051, Plant colour coding.

5.6.1.3 The following guide is applicable to components regularly encountered on mining projects:

Coating system Specification System

Galvanising repair

Painting

Structural steel* Hot dipped

galvanised unless painting is specified

SANS 121 (SABS ISO 1461 )

AA_CPS_41A CPS 132

Concession only

Vastra floor plates, all floors horizontal and inclined ≤5°

Hot dipped galvanised


AA_CPS_41A CPS 132

Handrailing, flooring & stairtreads



AA_CPS_41A -

Cast in plates/frames


foundation bolts, fastening)


AA_CPS_41A -

Stockyard Equipment

Consult specialist AA_SPEC_164000

and 164050 - TBA

Mechanical, electrical

equipment

OEM specification, approval / review

on request of Engineer

AA_SPEC_164000 and 164050

- OEM

Typical DMS plant tanks,

cells, distribution boxes and launders

Paint, Consult specialist

AA_SPEC_164000 and 164050

-

Internal - CPS 326,

External – CPS122

Water & Air piping


SABS ISO 1461 – heavy pipe

- -

Piping Paint, Consult

specialist AA_SPEC_164000

and 164050 - TBA

* All new steelwork shall be hot dipped galvanised in accordance with SANS ISO 1461 to comply with SANS ISO 14713 Table 2 e, long (10 to < 20) maintenance years i.e. minimum mean coating thickness of 85 micron (for steel > 6 mm thick). This requirement must be reviewed where the design life of the operation exceeds 30 years.

Where exceptionally low acidity levels are anticipated, particularly at DMS washing plant operations, a corrosion specialist must be consulted. Hot dipped galvanizing on its own is not suitable for these conditions and a duplex system or paint system may be required.

Table 4 – Coating System


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5.6.1.4 The Contractor shall be responsible for ensuring that he is fully conversant with the specification requirements as detailed under the utilization of each system.

5.6.1.5 A qualified applicator shall be defined as a workman regularly engaged in the application of protective coatings. Unqualified workmen shall be engaged in the preparation and cleaning only, prior to coating.

5.6.1.6 The Contractor shall provide all the facilities necessary in order to ensure satisfactory preparation and number and thickness of coats. All workmen shall at all times be under the constant supervision of a qualified supervisor.

5.6.1.7 The Engineer or his duly authorised representative shall be provided access to inspect the surface preparation and the application of any or all of the coats, to ensure that these have been applied in accordance with the specifications. No steelwork, pipework or items of plant and equipment shall be delivered to site until inspection has been carried out and a release issued.

5.6.1.8 It shall be the contractor's responsibility to ensure that inspection is called for and the necessary clearance certificates obtained prior to delivery of goods to site.

5.6.1.9 All equipment, motors, main plant, light fittings, etc. shall be suitably protected by means of wrapping or covering before grit blasting or spray painting any steelwork after the installation of the aforesaid equipment.

5.6.1.10 The Contractor must ensure that the correct materials are provided as designated in the specifications.


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6 INTERFACES

6.1 Civil

6.1.1.1 AATC design and construction contracts are structured such that civil works which are required to support materials handling systems are included under the mechanical design and construction scope which also includes structural steel.

6.1.1.2 Battery limits are not always identical on all projects but defined during the early stages of the project. Shown below are examples of typical battery limits:

Overland conveyor:

Route preparation Civil contract

Transfer station civil works Mechanical contract

Overland sleepers Mechanical contract

Tip:

Tip ramp and retaining wall Civil contract

Tip bin and support concrete works

Mechanical contract

Silo:

Concrete works, all inclusive Civil contract

Mechanicals, staircase, steel roof

Mechanical contract

Table 5 – Typical Contracts Battery Limits

6.2 Electrical Engineering

6.2.1.1 AATC design and construction contracts are structured in such a manner that electrical equipment and associated infrastructure required for Bulk Materials Handling Systems are designed according to an Electrical Load List provided by the Mechanical Designer which details the required motor ratings and speed. Motor specifications shall be according to AATC Specifications and shall be approved by the Electrical Discipline Engineer.

6.2.1.2 Electrical design for Motor Control and associated infrastructure is normally contracted in terms of a separate contract due to the nature of electrical bulk power supply. The battery limit in terms of Bulk Materials Handling Systems is the terminals of the drive motor/s associated with the BMH System. BMH Contractor responsible through AATC Supply Chain for supply of motors.


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6.3 Instrumentation

6.3.1.1 The requirements for instrumentation and controls supplied as part of packaged equipment is specified within document AA_REQ_673035, Packaged equipment and plants discipline requirement.

6.3.1.2 The integration option and associated instrumentation to be approved by the AATC Instrumentation engineer.


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DOC NO AATC000859

7 REFERENCES

7.1 AA Standards and Specifications:

Document No. Description / Title

AA_SPEC_114001 Design of Steel Structures AA_SPEC_114002 Construction of structural steelwork

ACSA_114012 Design Fabrication, Installation and Maintenance of Open Grid Grating for Floors, Stairways and Hand railing

AA_SPEC_114005 Steel and FRP Flooring, Stairs, Ladders and Guardrails

AA_SPEC_114010 Design of Concrete Structures AA_SPEC_114011 Construction of concrete work

AA_SPEC_164000 Users guide for corrosion prevention: System selection

AA_SPEC_164050 Corrosion Protection of Steelwork with Coatings AA_SPEC_164051 Plant colour coding

AA_SPEC_166005 Lubricants – specific requirements for industrial gear oils

AA_SPEC_166014 Lubricants – specific requirements for greases

AA_SPEC_248002 Materials handling Machines Structural Components Specification.

AA_SPEC_254001 Stacking and Reclaiming Equipment – Mechanical and Structural

AA_SPEC_255004 Apron Feeders AA_SPEC_371001 Conveyor pulleys and shafts AA_SPEC_373001 Belt conveyor idlers and rolls

AA_SPEC_373005 Installation tolerances for belt conveyors and structures

AA_BPG_375001 Conveyor guarding best practise guideline AA_SPEC_377002 Steel cord reinforced conveyor belting AA_SPEC_377003 Splicing of steel cord reinforced conveyor belting AA_SPEC_377005 Splicing of textile reinforced conveyor belting AA_SPEC_377006 Solid woven conveyor belting

AA_SPEC_377008 Splicing of PVC and nitrile covered Solid Woven Conveyor Belting

AA_SPEC_377010 Cold Splicing of Plied (Textile) Conveyor Belting AA_SPEC_415003 High Pressure Mine Water Reticulation Systems AA_SPEC_421017 General Purpose Valves AA_SPEC_673018 Conveyor Belt Protection Systems AA_SPEC_999022 Mechanical Standards AATC000168 Fire protection for buildings and structures AATC000169 Fire protection for conveyors and coal transfer


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7.2 National Standards and Specifications

Document No. Description / Title

SANS 14 Malleable cast iron fittings threaded to IS0 7-1

SANS 62-1 Steel Pipes Part 1: Pipes suitable for threading and of nominal size not exceeding 150 mm

SANS 121 Hot dip galvanized coatings on fabricated iron and steel articles - Specifications and test methods

SANS 719

Electric welded low carbon steel pipes for aqueous fluids (large bore)

SANS 971 Fire retardant textile reinforced conveyor belting (Solid Woven PVC)

SANS 1123 Pipe Flanges SANS 1173 General purpose textile reinforced conveyor belting SANS 1313 Conveyor idlers SANS 1669 Conveyor belt pulleys SANS 1366 Steel cord reinforced conveyor belting SANS 1431 Weldable structural steels SANS 4427 Polyethylene (PE) pipes for water supply

SANS 10083 The measurement and assessment of occupational noise for hearing conservation purposes

SANS 10103 The measurement and rating of environmental noise with respect to land use, health, annoyance and speech communication

SANS 10400 The application of the National Building Regulations

ISO 1461 Hot dip galvanized coatings on fabricated iron and steel articles -- Specifications and test methods

ISO 5048 Continuous Mechanical handling Equipment – Belt conveyors with carrying idlers – calculation of operating power and tensile forces

AWS D1.1 American Welding Society - Structural Welding CodeDD CEN/TS

13001-3-2

Cranes General design - Part 3-2: Limit states and proof of competence of wire ropes in reeving systems

PD 5403 Guidance on safe use of machinery

BS 21

Pipe threads for tubes and fittings where pressure-tight joints

are made on the threads (metric dimensions)

BS 436-5 Spur and helical gears. Definitions and allowable values of deviations relevant to radial composite deviations and runout information

BS466 Specification for power driven overhead travelling cranes, semi-goliath and goliath cranes for general use

BS 545 Specification for bevel gears (machine cut) BS 1640 Steel butt-welding pipe fittings

BS 3381 Specification for spiral wound gaskets for steel flanges to BS 1560

BS 3974 Specification for pipe supports. Large bore, high


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temperature, marine and other applications. (Withdrawn but still used in absence of alternative)

BS 3799 Specification for steel pipe fittings, screwed and socket welding for the petroleum industry

BS 6129: Part 1

Code of practice for the selection and application of bellows expansion joints for use in pressure systems. Metallic bellows expansion joints

BS EN 10226-1

Pipe threads where pressure tight joint are made on the threads

BS EN 10241 Steel threaded pipe fittings BS EN 10253-2

Butt-welding pipe fittings

BS EN 12513 Founding. Abrasion resistant cast irons BS2853 The design and testing of Steel Overhead Runway Beams

8 REVISION HISTORY

Version No. Reason for Change Date

Draft: Distributed to DRA, FLSmidth, HATCH, PH Projects, Taggart-JHDA, Taggart-LSL, and TWP for comment (T Schmidt, May 2013)

May 2013

Final Draft: Comments received from DRA, FLSmidth, HATCH, PH Projects, Taggart-JHDA, Taggart-LSL, and TWP incorporated (T Schmidt, August 2013)

August 2013

Published: New template format & minor updates. October 2013


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9 APPENDICES 9.1 Appendix A: Preferred Vendor List

Equipment and Preferred Vendors

Equipment Type

Ve

nd

or

1

Ve

nd

or

2

Ve

nd

or

3

Ve

nd

or

4

Ve

nd

or

5

Ve

nd

or

6

Air Compressor Atlas Copco

Assizing Process Automation

Thermo Fisher

Bearings SKF FAG (pulleys only)

Belt Arrestors ICO

Belt Ploughs Hosch Brelko Scorpio

Belt Scrapers - Primary and Secondary

Hosch Brelko Scorpio/Martin Eng

Belt Weighers Process Automation

Thermo Fisher

Schenck Process

Belting (Existing AATC contracts)

Goodyear/Veyance

Dunlop Fenner Phoenix

Brakes - Capstan Dymot

Brakes - High Speed and Low Speed

Voith Svendborg Binder

Centrifuges Malvern Ludowici

Multotec Seprotech

Andritz

Couplings - Fluid Voith Transfluid (BMG)

Couplings - High Speed and Low Speed

Transmission Components

Voith

Cranes Morris Kone Condra Demag

Cyclone Multotec Krebs FL Smidth

Malvern

Dust Suppression and Extraction Systems

Dustaway Mikropul Air Cleaning Equipment

Electro-hydraulic actuators

Dabeb Elram

Hytec

Elemental Moisture Density Analysers

Thermo Fisher

Feeders - Apron Metso MMD Bateman Osborn

Feeders - Observation

Osborn Metso Vibramech Joest Schenck

Feeders - Vibrating Vibramech Joest Schenck Osborn Magquip Vipro

Feeders - Grizzleys Osborn Vibramech Joest Schenck


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Fire Protection Systems

Fire Control Systems

Gearboxes Hansen Paramax Flender / Siemens

SEW David Brown

Hoists Morris Kone Condra Yale Demag

Holdbacks - External

Falk Marland

Hydraulic Power Packs

Denquip Hytec Hyflo Elco/ Ernest Lowe

Idlers (Existing AATC contracts)

Melco Lorbrand Osborn

Jaw Crushers Osborn FFE Sandvik

Lubrication Lincoln

Magnetic Separators

Multotec/ Magquip

Malvern

Overband Magnets Eriez Mechani Mag

EET Malvern Multotec/Magquip

Metal Detectors Process Automation

ABB Thermo Fisher

Mineral Sizers MMD Sandvik FFE (Abon)

Motors Siemens W.E.G / ZEST

Alstom CMG

Plate & Frame Filter Press

TH (Tecnicas Hydraulicas)

Ishigaki

Pulleys CPM Bosworth MS Pulleys

Pumps Weir Warman

Krebs MillMAX

Metso

Ring Roll Granulators

Bateman Osborn

Rock Breakers Atlas Copco Rammer CRM Osborn Metso

Rotary Breakers Osborn Bateman

Sampling Plant Packages

Multotec Thermo Fisher

Screens Vibramech Schenck Ludowici ConnWeld Linatex Joest

Stock yard Equipment -Stackers/ Reclaimers

Krupp Metso Tenova/ Takraf

Sandvik Schade FLSmidth

Thickener GKD Delkor MIP Outotec FLSmidth

Winches, Sheave Wheels and Ropes

Dymot Atlanta

9.2 Appendix B: Standard Drawings

Drawing Number Drawing Title 0000-0000-MED-0001 STANDARD HANDRAILING 0000-0000-MED-0002 *HOLD* GENERAL NOTES

0000-0000-MED-0003 ACSA - STANDARD A1 DRAWING SHEET TEMPLATE

0000-0000-MED-0004 SCREW TAKE-UP DETAIL

0000-0000-MED-0005 EQUIPMENT SCHEDULE , PULLEY SCHEDULE AND SOLE PLATE SCHEDULE

0000-0000-MED-0006 SLIDING JOINT DETAIL - 1500 WIDE BELT 0000-0000-MED-0007 BELT TURN-OVERS - 1200 WIDE BELT


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0000-0000-MED-0008 TAKE-UP CARRIGE - 1200 WIDE BELT 0000-0000-MED-0009 STANDARD INSPECTION DOOR DETAILS 0000-0000-MED-0010 HOOD AND SPOON CHUTE

0000-0000-MED-0011 ACSA - STANDARD A0 DRAWING SHEET TEMPLATE

0000-0000-MED-0015 STANDARD SKIRTS PL. CLAMPS 0000-0000-MED-0016 RADIAL DOOR DETAIL

0000-0000-MED-0017 TYPICAL SCREEN UNDERPAN SHEET 1 OF 2 (SPLIT)

0000-0000-MED-0018 TYPICAL SCREEN UNDERPAN SHEET 2 OF 2 ( SPLIT)

0000-0000-MED-0019 CUT-OFF GATE FRAME 0000-0000-MED-0020 CUT-OF GATE G.A. 0000-0000-MED-0021 CUT-OFF GATE DETAILS 0000-0000-MED-0022 TYPICAL SCREEN UNDERPEN SHEET 1 OFF 2 0000-0000-MED-0023 TYPICAL SCREEN UNDERPEN SHEET 2 OFF 2 0000-0000-MED-0024 FLOPPER GATE DETAIL 0000-0000-MED-0025 SILO CAST-IN DISCHARGE CHUTE FRAME 0000-0000-MED-0026 SILO DISCHARDG CHUTE DETAIL 0000-0000-MED-0027 SILO BELT FEEDER FEEDCHUTE DETAIL 0000-0000-MED-0028 MAGNET INSTALATION 0000-0000-MED-0029 SILO BELT FEEDER DRIBBLE CHUTE 0000-0000-MED-0030 SILO BELT FEEDER 0000-0000-MED-0031 SILO BELT FEEDER MECHANICAL DETAILS 0000-0000-MED-0032 SILO STRUCTURE ABOVE SILO SHEET 1 OF 3 0000-0000-MED-0033 SILO STRUCTURE ABOVE SILO SHEET 2 OF 3 0000-0000-MED-0034 SILO STRUCTURE ABOVE SILO SHEET 3 OF 3

0000-0000-MED-0035 CONVEYOR GANTRY - 1500 WIDE BELT - 24M LONG

0000-0000-MED-0036 CONVEYOR GANTRY - 1200 WIDE BELT - 24 M LONG



0000-0000-MED-0039 CONVEYOR 1200 WIDE BELT STANDARD OVERLAND MODULE

0000-0000-MED-0040 CONVEYOR 1200 WIDE BELT TURN OVER 0000-0000-MED-0041 TYPICAL DRIVE UNIT ARRANGEMENT 0000-0000-MED-0042 TYPICAL TRESTLES ARRANGEMENT 0000-0000-MED-0043 TYPICAL STOOL FOR TRESTLES 0000-0000-MED-0044 TYPICAL TAKE-UP TROLEY0000-0000-MED-0045 TYPICAL TAKE-UP FRAME



0000-0000-MED-0048 TRUNK CONVEYOR GA 0000-0000-MED-0049 U/G BOX FRONT ONE FEEDER LAYOUT 0000-0000-MED-0050 U/G BOX FRONT TWO FEEDERS LAYOUT


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DOC NO AATC000859

0000-0000-MED-0052 LOBSTER GATE DETAIL 0000-0000-MED-0053 WEIGH FLASK DETAIL 0000-0000-MED-0054 BOX FRONT FEEDED BY STATIC GRIZZLY 0000-0000-MED-0065 CONVEYOR GANTRY - 1050 WIDE BELT 0000-0000-MED-0066 PIPING - VALVE SCHEDULE

0000-0000-MED-0067 STANDARD ACCESS STAIRS FOR TAKE-UP TOWER & SILOS - 600 WIDE STAIRS

aatc design criteria and guidelines for surface infrastructure - mechanical & structural

Documents

mechanical design criteria

structural design criteria

process design criteria

generic design criteria

design codes

design perspective

detailed design information

detailed design stage