Alex Mtonga, BMT WBM - Minimising Conveyor Project Costs by Design

Minimising conveyor project

costs by design

Materials Handling Week, Brisbane

3 - 6 June 2013

Outline

• Introduction

• Conveyor system project costs

• Minimising costs by design

• Equipment selection

• Plant lay out (Maintenance)

INTRODUCTION

BMT is an international multidisciplinary science, engineering and technology consultancy.

BMT WBM is an Australian subsidiary of the BMT Group, with offices in Sydney,

Melbourne, Brisbane, Perth, Newcastle, Mackay, Denver and Vancouver.

BMT WBM has provided materials handling design and investigation services for over 40

years. Our experience in the field has included conveyor designs, modifications and

upgrades of existing systems.

In this presentation we explore ways in which we as designers can work towards

minimising overall project costs associated with a conveyor.

Conveyor system project costs:

Capital (initial) costs

Operating costs

Maintenance costs

• The total cost needed to bring a project to a commercially operable status.

• Costs associated with the day to day operation of the conveyor system. These

include both fixed and variable costs

• The costs incurred on activities which reasonably ensure that the design levels of

availability and performance of the conveyor system is achieved in order to meet

business objectives.

Conveyor system project costs

Costs due to lack of availability

Costs due to lack of reliability

• Costs incurred due to the conveyor system not being available to perform its

intended function as and when required

• Costs incurred due to the conveyor system not performing its intended function

as and when required

Minimising costs by design

Project business requirements and objectives

Minimising costs by design

Outages

In both planned and unplanned outage availability of a conveyor system

to perform its intended function becomes more important than the

supply and outage work costs due to production losses.

The designer has to understand the particular project requirements

and make design decisions appropriate for the particular project.

Provide an explanation of intended construction and installation

sequence plan to minimise duration of construction and installation

outage, hence minimise production losses

Minimising costs by design

Outages

Minimising costs by design

Removal sequence

• Magnet

• Magnet Frame

• Stair and Walkway

• Top of upper chute

• Scrapper

• Impact plate

• Upper chute

• Crossbeam

• Chute fingers

Minimising costs by design

Replacement sequence

• Chute fingers

• Packers adjusted

• New lower chute

• New Intermediate chute

• Grid mesh

• Modify upper chute

• Scrapper

• New impact plate

• Stairs re-installed

• Magnet

• Top of chute

Minimising costs by design

FIG. 3 –

Chute

installed and

in operation

Outages

Minimising costs by design

• Can determine the design to suit the construction requirements.

• Arrangement of construction work that has no direct impact on

the operations of the plant or equipment to be upgraded or

modified is possible before the actual outage.

Planned outages

Recently BMT WBM designed an intermediate drive unit with a

2 x 1000 kW drives. The unit was scheduled to be installed in a three

week outage but was installed and commissioned in less than the

planned three week outage.

Intermediate drive unit

Fig.4 -

2 x 1000 kW Drives

inserted into an

existing conveyor.

Business

requirement was to

minimise the

outage.

Intermediate drive unit

Fig. 5 - Intermediate drive unit. The unit was lifted in place in two fully

assembled sections connected by a pin joint and commissioned in less

than the outage planned timeframe of three weeks.

Intermediate drive unit

• Foundations were built in an early outage and buried and the

conveyor reinstated over them until the main outage.

Factors contributing in minimising the overall project costs and risk of

lost production included:

Intermediate drive unit

• The switch room and the VSD equipment including power supply were

erected besides the conveyor before the outage.

Intermediate drive unit

• The drive unit was fully assembled before the outage and lifted in

place in two sections connected by a pin joint. To complete the belt

line, two 30 m beam sections were used.

Impacts of programs

In projects with short programs, it is common for designers to make

decisions based on their past experiences and in most cases re-use

existing designs. Most often the decisions are based on incomplete

information and centred on meeting the program. Alternative solutions

are not fully investigated. The result is typically a conveyor system

design that meets the program but not optimised for the particular project

Figures 6,7 and 8 show such a case where the program was critical. The

design met the program but in operation the conveyor system had a lot of

tracking issues brought about by the screw take-up type considered in

the design.

Impacts of short programs

The screw take-up shown is considered not suitable. Difficult to

measure tension applied to the conveyor

FIG.6

Left & right take-up screws at tail pulley – Incorrect take-up tension settings

FIG.7 – Tail pulley tracked to one

side as a result of incorrect

take-up tension setting

FIG.8 – The servo roller on the

return belt tracker at the tail

end has worn through the

stringer as a result

Impacts of short programs

Impacts of programs

To get a more cost minimised design, the design team needs to get

involved early in the planning stage. Interaction between design costs

and other initial and ongoing costs need to be understood by both

designers and project managers if the lowest cost outcome is to be

achieved

FIG 9 – shows a 3-D model of new conveyors between and through

existing conveyors. Due to early involvement, the design team was

able to asses fitment of the new conveyors through a 3-D model

Early involvement of conveyor design team in

the project planning.

FIG 9 - 3 D modelling of new conveyors between and

through existing conveyors

Equipment Selection

Equipment selection can play a major role in minimising a conveyor

system life cycle costs.

• Must be selected considering the site conditions (more robust is often

better.)

FIG. 10 -

Columns

supporting

conveyors

damaged by

mobile plant

clean-up

Equipment Selection

• Selection must consider maintenance, including

- Skills required,

- Time taken for maintenance,

- Spares requirements,

- Ease of identifying faults, assessing condition.

• Should be a site standard, if practical.

• If it works why change it ? OR, Can it be done better?

Plant Layout (Maintenance)

The plant layout must be such that:

• It allows for maintenance to be carried out easily and efficiently.

• Minimises the number of steps.

• Minimises the time taken for the work.

• Has good access.

• Maintenance provisions are obvious.

• Includes lifting points, labels etc.

Figures 11, 12, and 14 show some examples of plant layout designs with

maintenance taken into consideration while Fig. 13 shows a typical example of

a design with no maintenance consideration

Plant Layout (Maintenance)

Fig 11

• Jack support,

Lifting lug,

• Bottom rail to

support pulley

in slack

position

• Removable

hangers to let

belt through

when hopper

is empty

Plant Layout (Maintenance) Fig 12

• Orange steelwork

is removable.

• Structure provided

for belt lifting

during pulley

removal.

• Lifting point

labelled.

• Concrete shaped

to facilitate

cleaning under

loading boot.

Plant Layout (Maintenance)

Fig 13 - Typical design

without maintenance

considerations

Fig 14 - Typical Design with

maintenance considerations

Plant Layout (Maintenance)

The designer needs to understand maintenance practices of the site where

the plant is to be used to ensure the design is appropriate to the site.

Some of the site specific issues that should be understood by the designer

include:

• The skill and capacity of site maintenance resources, and the availability

of local maintenance contractors. The design needs to suit the local

workforce.

• The maintenance equipment available at the site.

• The extent and type of existing plant on the site.

• The site power supply capacity.

Plant Layout (Maintenance)

• Environmental and land use issues. The choice of conveyor routes, and

overall design of the conveyors is often determined by the particular site

limitation, such as wetlands, culturally significant areas and residential

areas.

• How often the plant will be operated and how critical reliability issues are.

Conclusion

In conclusion, we can only encourage conveyor designers, project managers

and site personnel to communicate, to ask questions, and to listen to other

opinions, in order to make design decisions that truly minimise the cost for

the particular project.

Thank you / Questions

Alex Mtonga / Gary Ryan

t: (03) 8620 6100

e: [email protected]

e: [email protected]

w: http://www.bmtwbm.com.au