360 degrees magazine issue 6

ISSUE 6 2012OUR GLOBAL VIEW OF A VIBRANT WORLD

THE ISSUE

THINKINGIN ACTION

SOLAR & NATURAL GAS SYNERGIESFACE TO FACEMANAGING TUNNELLING RISKIN NEW ZEALANDBLADDER TECHNOLOGY

CONTENTS 04

06

08

12

14

20

24

26

34

38

40

INTRODUCTIONCompetencies at the heart of innovation

SUSTAINABLE ENERGYCreating solar and natural gas synergies

FACE TO FACEGood corporate citizenship or commercial advantage?

WIND FARM DEVELOPMENTSGetting energy prediction right

WHERE HAVE ALL THE MINERALS GONE?

We talk to Aurecon’s Mining Infrastructure Leader

GOING UNDERGROUNDManaging tunnelling risk in New Zealand

MEULWATER WATER TREATMENT WORKS

Securing a reliable water source for Paarl’s increasing demands

BLADDER TECHNOLOGY IN BACKHAUL

The future potential of bulk rail transportation

SAHMRITurning architectural creativity into

innovative structures

INTEGRATED APPROACHIN STRUCTURAL DESIGN

Tall buildings

OIL AND GAS INDUSTRYKeeping supplies fl owing to meet growing demand

Aurecon Thinking in action

WELCOME

energy generation and distribution, whole of life infrastructure and asset management, alternative energy sources, smarter buildings, and more integrated urban environments are moulding the future.

At Aurecon, our culture encourages new ideas, creativity and the application of new technologies. We are proud of the sheer breadth

THINKINGIN ACTION

Our people are motivated by seeing their thinking in action, applied in ways that make business sense for our clients, adding business value through innovation, operational and cost effi ciencies; and that add to our clients’ bottom line.

Innovation is changing the way the world works. Sophisticated transport systems, new approaches to mining,

“The power of innovation is in all of our hands.”and depth of technical, delivery and advisory expertise we offer and the deep client relationships we build.

This issue of our 360° magazine illustrates how industry understanding combined with technical smarts creates business opportunity and addresses challenges. We hope you enjoy it.

Regards,

Paul HardyChief Executive Offi cer, Aurecon

Jakes GerwelChairmanAurecon

3

At Aurecon our industry and client understanding drives our technical expertise to deliver solutions that work. To support this we have established 26 core ‘competencies’ – key areas of expertise through which we link our key client relationships to our extensive technical offering.

Our competency leaders, who include some of the world’s leading technical and advisory practitioners, work with our clients to assess each situation and to workshop the best solutions. The dialogue this creates is exciting for our clients and for us – solutions can come from several areas of expertise.

Our culture encourages a continuous focus and energy directed towards enhancing our capabilities. In doing this,

Competencies at the heart of innovation Peter Turner, Aurecon’s Head of Competencies, looks at what competencies mean to our clients – now and in the future.


INTRODUCTION

Competencies at the heart of innovation we ensure that we share our knowledge group wide and with clients no matter where their projects may be located.

Already many of our clients are benefi ting from regular workshops with relevant competency leaders – you will fi nd a list of our competencies on pages 30–34. If you have a question regarding a challenge in your industry or would like to spend some time discussing alternative ways to maximise an opportunity, please contact me and I can arrange for a conversation to take place or arrange a workshop.

Regards,

Peter G TurnerCompetency Leader, [email protected]

5

Our competencies

Asset Management

Airports

Building Sciences

Building Services

Building Structures

Bulk Materials Facilities

Bulk Water & Dams

Business & Infrastructure Advisory

Environmental & Community Planning

Ground Engineering

Health

Information & Communications Technology

Land Infrastructure

Manufacturing

Mining Infrastructure

Ports & Coastal

Power Generation

Power Transmission & Distribution

Programme & Project Delivery

Rail

Renewable Energies

Roads

Sustainability

Urbanisation

Water Resources Management

Water & Waste Water Treatment

Hybridisation: the short-term goalCurrent global efforts to reduce CO

2

emissions, including the carbon tax in Australia, will inevitably place additional pressure on utilities and industrial plants to operate at competitive costs. Many operators and proponents are looking for reliable power generation options that are green and cost effective. Renewable energies such as solar thermal have made progressive leaps in technology in the past decade, as has access to newly discovered natural gas deposits across Australia. When combined, these two resources tick all the boxes.

The hybridisation of open-cycle gas turbine (OCGT) and combined-cycle gas turbine (CCGT) plants with concentrated solar power (CSP) systems is key to achieving this.

Of particular interest is the retrofit of solar towers to reduce cost and allow independent operation of CCGT and CSP plants.

Integrated solar combined-cycle (ISCC) plants are very suitable for Australia as natural gas reserves and solar irradiance are abundant. Several existing plants are in suitable locations and could be retrofitted.

CSP technologies are considered capital intensive to construct and implement. Therefore hybridisation has cost-reduction benefits in terms of sharing equipment and knowledge for technology providers, operators and financiers.

Integration the keyCurrently, a number of CSP plants are in operation around the world in

the USA, Egypt and Morocco, with plants currently under construction in Australia including CS Energy’s Kogan Creek and Macquarie Generation’s Liddell power stations. The largest ISCC unit in operation is the 75 megawatt (MW) Martin Next Generation plant in Florida, USA.

All existing hybrid plants use the well-established parabolic trough solar technology, providing saturated or slightly superheated steam to the heat recovery steam generator (HRSG), where further superheating-to-steam turbine requirements take place using the hot gas turbine exhaust. This concept is proven in several plants but requires both plants to operate simultaneously. Parabolic trough plants using thermal oil are the most mature CSP technology. However, steam temperatures are limited to less than 390°C as the thermal oil used degrades very quickly above 400°C.

With more solar plants commencing operation and construction around the world, such as Torresol’s Gemasolar project in Spain and Brightsource’s Ivanpah project in the USA, the technology is becoming more mature and bankable.

Significantly higher steam qualities (greater than 540°C and 140 bar), compared to parabolic troughs, allow

Amir Tadros, a Senior Mechanical Engineer within Aurecon’s Energy Services group and advocate of sustainable energy.

Creating solar and natural gas synergies


To keep the gas turbine efficiency high, low-temperature CSP heat could be used to chill its inlet air.

The capacity of the solar plant is mainly driven by the part-load efficiency of the steam turbine. A 100 MW steam turbine remains efficient down to 50 per cent part-load. With the HRSG providing sufficient steam to generate 50 MW base load, the steam turbine is operating at a good efficiency during the night with power peaking at 100 MW at daytime through additional CSP steam. Using thermal storage would allow a larger solar contribution when night time energy could be drawn from the storage tanks to keep the steam turbine operating at higher loads. The main stack in this scenario would need to be approximately 30 metres higher than required for a stand-alone CCGT plant to ideally locate the solar receiver.

To optimise the heliostat field size and avoid optical losses due to mirror wobble, the heliostats are arranged in a 320° circle around the plant, with the main stack in the centre. Steam turbine, cooling towers and buildings are arranged adjacent to the main stack/solar tower. To avoid thermal losses, the steam turbine is placed close to the steam generators. The ISCC plant could be either air or water cooled with air cooling being the more likely option, considering water scarcity in remote sites and avoidance of plume formation.

The carbon dioxide intensity of the proposed ISCC plant, is 365 kilograms per megawatt hour (kg/MWh), which is 60 per cent lower than the 2005–07 Australian generation portfolio average. Using 15 hours of full load thermal storage has the potential to further reduce the carbon intensity to 308 kg/MWh. Depending on the remoteness of the site and infrastructure availability, the cost of electricity from such an ISCC plant can vary from USD 140 to USD 180/MWh.

Power for the futureISCC plants are ideal for sites with a high DNI, abundance of natural gas and a requirement for reliable power all year round. The hybridisation of CSP technologies reduces capital expenditure significantly, allowing the construction of reliable low carbon intensity power plants today without significant or indeed any government subsidies.

Remote sites, such as mines, suffering from high electricity prices stand to benefit from ISCC plants particularly when OCGT/engine plants are the current source of power generation. Reducing the carbon intensity of power generation by a potential 60 per cent, compared to the 2005–07 Australian generation portfolio average, is significant and would help Australia meet its emission reduction target cost competitively. This also has numerous financial flow-on effects for the mining industry which will strive to keep export prices, and therefore operational costs, competitive.

You can contact Amir at [email protected]

simple and efficient integration into the high pressure/temperature component of the CCGT’s steam cycle. Both plants are able to operate independently when both steam generators are able to provide identical steam qualities.

Operators of ISCC plants generally understand and appreciate the cost savings gained by sharing equipment such as the steam turbine, condenser, feed water systems and auxiliary equipment. However, an ISCC using a solar tower has the additional benefit of sharing building infrastructure. For example, the main stack can be modified to support the solar receiver. This could provide a good cost-saving opportunity as, according to a 2011 study by Hinkley et al, the tower in a stand-alone plant requires approximately 5 per cent of the total investment.

The conversion of OCGT to ISCC plants increases the fuel conversion efficiency and reduces investment as a significant portion of the equipment is already on site, such as the gas turbine and plant control system. Adding the heat recovery steam generator (HRSG) and solar tower Rankine cycle, is in this case, more cost competitive than building a greenfield ISCC plant.

Thermal storage references exist for parabolic trough and solar tower technologies. Implementing thermal storage has the potential to maximise the solar contribution but depends strongly on the value and ability of energy to be dispatched. Historically, electricity demand is higher during the daytime and that’s when the solar plant can provide the additional capacity needed.

The possibilities are endlessA number of locations in Western Australia, Queensland, New South Wales and South Australia have an excellent Direct Normal Irradiance (DNI) as well as access to natural gas. Typically, a DNI of 2 000 kilowatt hours per square metre (kWh/sq m) per annum is required for a stand-alone CSP plant but due to cost-reduction benefits of ISCC, plant areas with a DNI as low as 1 600 kWh/sq m per annum could be considered.

At 200 MW, CCGT plants realise overall efficiencies of 55 per cent resulting in a very efficient use of

gas compared to backup boilers in traditional CSP plants. Larger units could even realise up

to 60 per cent conversion efficiency. ISCC plants are likely to operate in high ambient

temperature environments, which reduce the gas turbine efficiency.

This article was originally compiled by Juergen H. Peterseim, Institute for Sustainable Futures University Technology of Sydney; Dr Amir Tadros, Aurecon Australia; Prof. Stuart White, Institute for Sustainable Futures University of Technology Sydney; and, Prof. Udo Hellwig, ERK Eckrohrkessel GmbH.

7

Paul Thorstenson is Aurecon’s Chief Administration Offi cer and a member of the Aurecon Board. He chairs the ANZ & Asia Diversity Leadership Team. Previously Aurecon’s General Manager for Australia, Paul was responsible for the effective operations, business improvement initiatives and management of overheads. Over 30 years, Paul has gained wide-ranging experience in civil, structural and industrial engineering projects, including building design and major industrial plant expansions.

Zohra Ebrahim is a non-executive Director of the Aurecon South Africa Board. She is the chair of the Aurecon South Africa Diversity Forum and sits on a number of external boards and advisory bodies. Her commitments include being Deputy Chair of the Desmond Tutu HIV Foundation, Chair of the South Africa Social Housing Regulatory Authority and former President of the South African Institute of People Management (the fi rst black female president for the Institute).

Good corporate citizenshipor commercial advantage?

Two of Aurecon’s diversity champions discuss what diversity means for modern, global organisations.

FACE TO FACE


People often think diversity is about being a good corporate citizen. For diversity to work, every single person in the organisation needs to move past this ‘tick the box’ mentality and see the enormous commercial advantage a diverse workforce brings. At Aurecon, we believe building a diverse workforce is smart business. A workforce representing a diverse range of races, gender, ages and lifestyles, is essential to realising Aurecon’s vision of being ‘Leading, Vibrant and Global’.

They are some very valid points. Another aspect relates to our ability to interact with clients wherever they may intend operating. Our clients trust us to deliver market leading solutions based on localised knowledge, regardless of where their project is. As our clients expand their interests into new regions, Aurecon’s diverse workforce ensures we have the right people with the skills, sensitivity, experience and confi dence to work within and alongside various cultures and across national borders.

That’s right. The diversity of our people is a strength of Aurecon. We have employees in 25 countries around the world and there are more than 32 different languages spoken within our business – all sharing common goals and focusing on one vision. The commercial advantages of such a diverse workforce complements the Group’s high performance culture.

Don’t you think that the wide-ranging benefi ts of diversity are often not fully appreciated? For example, in terms of recruitment, it enables us to select top talent from a much larger pool of candidates, as more people want to work for a company where diversity forms the core of their workforce. Coupled to this, having a more diverse group of managers not only assists with the need to have top talent, but also helps to retain employees as they can actually see the opportunity to grow their careers regardless of, for example, their race or gender. Of course, different diversity priorities may dominate at any given time in any particular country but we should be aware that diversity is a multi-faceted issue. In gaining and retaining top talent, we improve our innovation capabilities through employing the best. We also meet our clients’ expectations of receiving world-class services and solutions, as well as their expectations of partnering with a company that puts its money where its mouth is when it comes to diversity and lives diversity as a core value.

I suggest that it is not only the capability of working across national boundaries, it is the fact that people from different backgrounds often bring different perspectives to the problem-solving process. Also, the people in a country, anywhere, are never entirely homogenous – so it is also about expressing sensitivity without reacting in a culturally stereotyped way.

This is invaluable when coming up with integrated, holistic solutions and also enables us to be more aligned with clients, who also have diverse workforces with associated specifi c needs. Embracing diversity enables us to be more naturally in tune with these needs and to automatically provide our clients with solutions that from the onset take into account ways of overcoming any sensitive cultural or religious issues.

This should extend to the recruiting pool being as diverse as possible, with an emphasis on the specifi c skills and/or demographics that we would like to address. Once all potential candidates have been given a fair chance, the best people are recruited for the job. This ultimately helps Aurecon provide excellent client service by actively recruiting with diversity in mind.

Good corporate citizenshipor commercial advantage?

FACE TO FACE 9

The concept of diversity incorporates so many aspects of what makes us all individual. Gender, race, employment equity, age, disability, religion, lifestyle and culture – a unique balance between these shapes individuals, as well as different experiences and points of view. If well-managed, leadership groups and wider teams benefi t enormously from the different perspectives a diverse workforce brings.

I agree. However, while we celebrate this diversity, we acknowledge that diversity management is not always easy or automatic. Indeed, diversity needs to be driven at the highest level to demonstrate commitment and provide leadership and direction on this critical subject.

When Aurecon was formed more than three years ago, we had thousands of people from across the globe being called to work together as one. Since then, the company’s leadership has put resources and effort into building a strong sense of team amongst employees and in cultivating this ‘Aurecon culture’ through clear communication, team building initiatives and targeted employee engagement programmes. The inclusion of specifi c diversity questions in our exit interviews and employee engagement surveys is an example of how we are gathering feedback from staff to identify what we do well concerning diversity and what areas require greater attention.

Allied to the above, the Group has consciously created diversity forums to recognise and develop the benefi ts that managing diversity brings. This means addressing diffi cult questions sometimes and being prepared to acknowledge that alternate perspectives coexist. Arising from this, our global diversity business case is based around four key outcomes, as well as a shared belief that diversity is essential. The outcomes were that, as a global organisation, we should:

1. Equip our people with the skills, sensitivity and confi dence to work within and alongside various cultures, and across national borders

2. Take advantage of the benefi ts of different perspectives within leadership groups and teams

3. Maximise the available resources talent pool, including attracting, retaining and developing female talent

4. Respond to increasing client expectations for tangible diversity management (gender, race, employment equity, disability and culture)

While in their relative infancy, these forums are already engaging with employee groupings such our emerging professionals group – Limelight and and Aurecon Women Achieving Women to address youth and gender issues respectively, to further our aim of ’Fostering Human Achievement’.

The diversity forums lead our transformation efforts to affect positive change across a number of dimensions and support our wider corporate social initiatives. This transformation is a key priority for us and encompasses other themes such as Broad-Based Black Economic Empowerment, skills development and positive procurement. While we are still in early stages of our transformation journey, we are already seeing some real, measurable change. For example, of the 20 carefully-selected benefi ciaries in this year’s bursary intake in South Africa, 15 were black and eight were women.


Aurecon and diversityAs a global organisation, Aurecon aims to equip its people with the skills, sensitivity and confi dence to work within and alongside various cultures and across national borders. We take advantage of the benefi ts of different perspectives across our leadership groups and teams. Our aim is to maximise the available resources talent pool, including attracting, retaining and developing female talent and championing Broad-Based Black Economic Empowerment (BBB-EE) for Aurecon in South Africa.

But wouldn’t you agree that diversity is not a one-size-fi ts-all outcome; each region has different diversity issues? In some areas of the world, it is ensuring cultural diversity. In others, it may be around age and in other parts of the world gender may be the key issue. One of the challenges of a global workforce is understanding each region’s unique challenges and what we can do to overcome them. It is also in developing initiatives that ensure not only a diverse and inclusive workforce but also wide-based representation in our leadership teams.

As you rightly pointed out, different regions have different diversity challenges, some of which have to be overcome by all global companies. Aurecon and our partners and clients are by no means exempted from those challenges.

Probably the biggest diversity challenge lies in the fact that many diversity issues are interlinked – the one infl uences the other. Therefore, you have to tackle all issues and perform well in all areas of diversity to truly be leading the marketplace when it comes to diversity and of course performance must be more than perceived, it must be managed and felt within the organisational culture.

To have a competitive edge, you must attract the best talent and experts. To achieve this, your workplace and diversity policy needs to be inclusive and, more importantly, sustainable as these individuals would rather associate themselves with a company that truly embraces diversity rather than window dressing to suit the situation. With a diverse workforce in place, more innovative solutions can be achieved as different people approach problem-solving differently. Attracting a more diverse range of clients and partners is also easier as a diverse workforce can associate with a diverse group of clients and partners – leading to business expansion into more regions.

Although the challenges of getting diversity right are undisputed, investing in policies and procedures that enhance a diverse workforce is well worth it and only when policies and procedures are accompanied by actions and good practice, will we have changed to how society expects us to behave as good corporate citizens, as well as reap the commercial rewards.

FACE TO FACE 11

Wind farmdevelopmentsGetting energy prediction rightby Blair Walter, Aurecon’s Renewable Energy Leader



Good commercial decisions require robust predictions Making good commercial decisions at each stage of wind farm development requires robust predictions of the site’s future energy yield. But at early stages when project feasibility is unconfi rmed, developers are often reluctant to spend large sums of money assessing the wind resource. Even at fi nancial close on some projects there still does not appear to be suffi cient understanding of the site wind resource to provide a reliable energy yield prediction.

Aurecon has been involved in a number of reassessment exercises in Australasia and Europe to determine actual long-term output of wind farms once they have been operating for a few years. We have observed a trend towards over-prediction in preconstruction estimates of operating wind farms, possibly caused by a tendency to invest in more over-predicted projects as they appear to offer better economic performance. Developers may drop under-predicted projects as investment options as they may not appear to be viable investments.

Over-prediction worsens when accompanied by underestimation of the uncertainties contributing to exceedance values relied on by banks and equity investors. We have observed a number of projects where the P50 from reassessment using operating data is below the preconstruction P90 energy output level (P50 and P90 are values widely used by banks and investors as a base performance measurement in their fi nancing decisions). Understandably, investors continue to be concerned about wind risk and the accuracy of output predictions for new projects.

Three main challenges in wind resource assessment The wind is a natural system and therefore non-linear in its short term behaviour, which makes it diffi cult to model and predict. Three of the main challenges in wind resource assessment are:

1. Calculating a long-term wind climate for the site from a short period of measured data

2. Modelling wind fl ow across the site in order to predict wind speed at each turbine location

3. Extrapolating data from short mastsup to turbine hub-height

A good wind monitoring campaign should focus on reducing the uncertainties associated with these activities to target levels, through collecting multiple annual cycles of data, monitoring at enough locations across the site to reduce wind fl ow modelling errors, and monitoring at or near turbine hub-height.

In the early stages of development, the full extent of the project may be unknown. Furthermore, assessment of engineering and environmental effects and stakeholder consultation may, over time, change the project extent. This can make it diffi cult to design a wind monitoring campaign that results in suffi cient wind data at the time of the fi nal investment decision.

Our recent project proving groundAurecon has overcome these challenges using a combination of traditional and advanced technologies. For a mega wind farm (>500MW) currently under development in Australasia, Aurecon identifi ed the site using in-house mesoscale meteorological modelling of wind speeds combined with GIS analysis of terrain. We then used this information to develop a preliminary assessment of the potential wind farm including layout of turbines, wind resource assessment and energy yield prediction – all before a single mast or land rights agreement was established. Our client was then able to understand the development potential of the whole area and begin discussions with the landowners whose properties the project covered.

Our client erected two 80 metre masts in 2009 (with Aurecon’s assistance) in central locations selected to confi rm the predicted wind resource from mesoscale modelling. After initial confi rmation of the wind resource, another four 80 metre masts were erected at locations selected to form a backbone of wind measurements from the site. Over the next two years, using remote sensing (LiDAR) we measured wind at several additional locations carefully selected to provide representation of all turbine positions in the layout. Due to having

a backbone of quality 80 metre masts for correlation, only short monitoring periods of a few months were required at each LiDAR location.

Three years on, and with engineering assessment completed and a permitted project, we have confi rmation of the wind speeds at the levels predicted in the original mesoscale modelling investigation and the wind farm layout is similar to the preliminary assessment. Due to the approach we took on this project, with uncertainty reduction at the core of the development process, abortive development-spend was eliminated.

Using these advanced tools reduces uncertainty from the outset of the

project development process, and thereby reduces the likelihood of over-prediction in the fi nal investment analysis.

Aurecon holds a leadership position in wind energy providing consultancy services to project developers and fi nanciers. Our wealth of global expertise and our extensive range of technical advisory services will give clients a competitive advantage and help them realise maximum project value.

About BlairBlair is a mechanical engineer and Aurecon’s Renewable Energy Leader. He has 16 years of experience in the energy advisory sector incorporating a range of technical and commercial projects in New Zealand, Australia, Indonesia, Brazil, Turkey, Mexico, South Africa and Europe.

Blair’s primary focus is renewable energy and his recent experience includes development support on wind and solar projects at all stages of development from conception to fi nancial close. Blair has specialist skills in due diligence for acquisition transactions, energy yield assessment and contract strategy.

You can contact Blair at [email protected]


“The wind is a natural system and therefore non-linear in its short term behaviour, which makes it diffi cult to model and predict.”

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Where have all the minerals gone?minerals gone?by Andrew Keith, Aurecon’s Mining Infrastructure Leader

From Australian Bureau of Statistics, “5625.0 Private New Capital Expenditure and Expected Expenditure, Australia”, Sept 2011

Australian mining project expenditure

Enabling infrastructure(Mine, Transport, Power, Water) Plant, Equipment and Machinery

100%

75%

50%

25%

0%

Dec-1998 Dec-2001 De-2004 Dec-2007 Dec-2010


Behind this fundamental truism lies onion-like layers of issues and challenges that impact all new mining developments to some extent: rugged terrain; lack of infrastructure; working with and in underdeveloped communities; government approvals; relatively pristine environments. With the progressive mining of easier deposits, typically closer to export ports or users, the signifi cance of these challenges in gaining approvals and licence to operate and the cost of getting the ore to the customer increases.

Among the most critical of these challenges, is that of a pit to port transport chain, both in terms of viability of the project (the project has no value if the ore cannot get to market) and cost (long transport chains cost more to build and operate).

Mining in the 21st centuryIn an article titled ‘The problem with railways in Australia’ (International

Longwall News, 3 February, 2012) the view was expressed that coal and iron ore have less to do with mining than with transport, economics and infrastructure. These, being the bulkiest of bulk resource commodities, make the point particularly clear – but it is also true of other minerals. Australian Bureau of Statistics fi gures indicate that since 1998 the balance with respect to mine development costs has changed from being equipment (mining and process) dominated to being heavily weighted to enabling infrastructure.

Ore transportation has always been a challenging issue but these current trends have resulted in a new focuson getting the most effi cient transport chains and achieving lowest cost to market.

While undergoing renewed focus, the means of pit to port transport remain unchanged; roads, conveyors; rail; and, where there is navigable water, barging. The renewed focus is on achieving low capital cost transport as far as possible commensurate with a sustainable, effective and cost effi cient transport chain for the life of the mine. Critical challenges centre on the economics of the traditional transport options and fundamental assumptions applied to mine developments over generations of project managers. Rather than build the ‘biggest hammer’ – a peak production transport system from the outset - closer examination of the benefi ts and risks of staging are becoming more important in developing ore transport chains.

The mines are getting further from the beach. This brief statement encapsulates a key issue facing new mine developments globally as we move further into the 21st century.

15

Safet

y

Road – public highway vehicles

Road – heavy haul vehicles

Railway

Conveyor

Barge

CapEx

OpEx Horizonta

l

alignm

ent

Vertic

al

alignm

ent

Distan

ce

Capac

ityFo

otprin

t lan

d

acquisi

tion

Social a

nd

eviro

nmen

tal

impac

t

Low Very hIghTight curves at very low

speedsLowLow Low

Medium to high

Medium

HIgh HIgh LowMin radius

1 000m+/-1% High High

Medium to high

Medium

Medium to low

MediumMedium to

high

Min radius 750m at 70km/h

+6% / -8%Medium to

highMedium High

Medium to High

HIgh HIgh Low

LowLow to

medium

Min radius 3 000m

+15% Low HighLow to

mediumMedium to

high

MediumRiver – 4m min depth

High High Low Low

Less desirable

Moderate desirability

Highly desirable

Transport method attributes

• Ore quantity – Global ore grades continue to decrease (while ore body complexity increases), mines continue to get larger, fuelling the need for bigger transport infrastructure to support the pit to port ore chain.

• Ore quality and durability – Transportation of ores over longer distances increases the potential for degradation. Numerous transfers between transport systems can exacerbate this. Degradation can reduce the product’s value and there fore margin from the mining project.

• Distance – As ore haulage distances grow, the need for higher volume, lower cost per tonne-kilometre transport systems increases. These typically come at higher capital costs.

• Terrain – The nature of the terrain dictates the overall cost of any specifi c transportation method. Increased horizontal and vertical alignment fl exibility will reduce capital cost from earthworks and bridge structures but will generally result in higher operating costs. With longer ore chains, the potential to encounter rugged terrain is higher for each mine.

• Ground conditions – Like terrain, ground conditions impact cost and therefore alignment selection. Swampy land provides a fl at vertical

alignment but involves additional cost in supporting the transportation infrastructure.

• Access to navigable water – Where navigable water is available, water transport becomes a potentially viable option for long distance high volume transport.

• Location and type of processing facilities – Transport of value reducing, or unsaleable, water (as elevated moisture content), air (as voids due to large particle size) or deleterious material increases the overall cost of transport per tonne of ore. As transport chains become longer this cost increase may become a signifi cant percentage of overall delivered cost. Location of benefi ciation and processing as close to the mine as practical is therefore an important consideration.

Less quantifi able, softer issues also play a key role in transport chain selection. We can liken the ore transport chain to an umbilical cord, sometimes stretching over many hundreds of kilometres. As such, the entire mine production and income is dependent on maintaining the integrity and capacity of this chain, with little opportunity to build in any redundancy to mitigate the risk. Key aspects requiring consideration,

beyond pure cost and economics, when choosing the transport chain include:

• Environmental – Longer ore chains potentially encounter more environmentally sensitive areas that either need to be avoided or involve special treatment.

• Social and community – A long ore chain presents the mining company with a large number of potentially diverse communities to engage and negotiate with to establish and maintain a societal licence to operate for the transport chain, and therefore delivery of the mine product to market. A key indicator of social licence is in the land acquisition required for the ore chain, a process which, while generally being of low cost by comparison with the overall project capital outlay, often lies on the critical path and can in fact hold up fi rst production and time to market.

• Political and regulatory – These two issues are closely interrelated and with mines going further inland in Africa, cross-border issues become critical. Even crossing provincial borders within countries can raise regulatory and political confl icts.

Choosing the optimal transportation method, or combination of methods, is therefore a project by project proposition based on a balanced consideration of all the issues above for the specifi c environment and project needs.

Choosing a Transport ChainImplications on the main forms of transportation, and their economics, have changed the view on, and utilisation of, these transport methods. Selection of the optimal form of transportation, or mix of forms, is project specifi c and depends on a holistic view of a range of cost and engineering factors including:

Navigable river required

>10% possible at low speeds

Comparison of ore transport modes


A brief summary of some of the cost drivers and industry trends of the main transport methods follows.

RailIncreasing distances from mine to port cement the high capacity, low operating cost and good safety record of rail transportation as the generally preferred transport mode. The main barriers to use of rail, particularly for start-up mines, and those in rugged inland areas, are the high capital cost and the low fl exibility available in vertical alignment. Combinations with overland conveyors, or road haul, through rugged terrain at the mine end are not uncommon, prior to loading onto rail. Sharing of rail infrastructure between mine projects, and staging of rail system development and investment provide good opportunities to realise the benefi ts of rail while minimising the downsides.

The Moatize-Nacala railway study and South African iron ore export (Orex) channel are recent case studies which demonstrate these issues.

Moatize-Nacala railway study, MozambiqueUsing the Multi-Criteria Assessment (MCA) planning tool, Aurecon was able to demonstrate the relative merits of the different alignment options from an engineering, geotechnical, operating, social and environmental perspective. This approach gave our client a full understanding of all the pertinent aspects and enabled them to pursue the option that was engineering and operationally sound, and would have the least social and environmental impact. Consequently, project implementation is not likely to hit unexpected hurdles.

South African iron ore export (Orex) channelThe project presents many challenges – not the least of which is the length of the supply chain. The Orex channel is an 850 kilometre rail line linking Sishen in the Northern Cape region with the Port of Saldanha, to the north of Cape Town. Our team brought together key skills in port, bulk materials handling, and rail (operations planning and economics) to contemplate a true pit to port solution taken from a whole of logistics chain perspective.

Whereas one solution may have taken the position of more infrastructure to address the problem, our approach was a whole-of-supply-chain perspective, with a view to improving each element of the chain to its optimal effi ciency before resorting to the expense of adding or expanding infrastructure. We fi rst clearly identifi ed the intrinsic interdependencies of the various elements - and how each impacted on the other to diminish the overall effectiveness of the chain. Despite the process nature of this, such thinking is far from typical within rail engineering fi rms.

Our approach was to focus on improving operational effi ciency through a master plan. The plan approach (as opposed to previous studies that proposed an infrastructure intensive solution as the only one) contemplated up to seven expansion steps/options to deliver the nominated tonnage growth, at much reduced cost to industry.

ConveyorsLow effective distance limits the applicability of overland conveying as a single solution to the ore transport issue for long chains. The longest single fl ight conventional coal conveyor, at North Curragh Coal Mine in Queensland, Australia, is about 20 kilometres. Longer distances are possible with multiple fl ights. An 11 fl ight phosphate conveyor

in the Western Sahara extends 100 kilometres, but each transfer contributes to ore degradation into smaller particle sizes.

Consequently, and due to their relative fl exibility of vertical alignment and low ground footprint, conveyors are often used at the rugged mine end and/or the softer ground of the port end as a low operating cost link between the fi xed infrastructure and main transport chain.

The relative infl exibility of conventional conveyors in horizontal alignment is thus a major challenge in this regard. More fl exible alternatives such as cable belt or pipe conveyor can sometimes address this. A recent example at the Hidden Valley gold mine in Papua New Guinea has a 5.3 kilometre pipe conveyor, the Indiana Jones Conveyor, connecting the mine and process plant on ridges by dropping 500 metres to cross the valley and rise again, and in the process going through horizontal turns totalling 719 degrees, or twofull revolutions.

In recent history, advances in belt technology, especially belt rubber and idler technology, have led to lower resistance and wider spaced idlers, contributed to higher speed and capacity conveyors with, counter-intuitively, reduction in the belt grade required due to reduced friction and hence reduced belt tensions.

75% 40%

>75% – the proportion of new Australian mine development capital cost for infrastructure since 2010.

<40% – the proportion of new Australian mine development capital cost for infrastructure pre 2001. In developing countries these percentages are even higher.

2010 2001

17

These material and component improvements, combined with improved dynamic analysis, have enabled conveyor technology to push previously defi ned limits.A maximum speed for conveying of 5 metres per second was, in the recent past, considered reasonable. The PT Kaltim Prima Coal (KPC) 13 kilometre overland conveyor connecting the Sangatta mine coal handling and processing plant with the Tanjung Bara coal port is now running at 8.7 m/s, delivering some 30 Million Tons Per Annum (Mtpa) of coal to the port along a single conveyor line. The future

continuations of these advances are likely to further extend the carrying capacity and maximum fl ight length of conveyors.

Conveyors as the main transport solution for long ore chains present some non techncal issues in termsof community and environment. They have the disadvantage of presenting a permanent physical barrier across the landscape dividing environments and communities in a way rail or roads do not. This in turn presents risks around securing such

a long narrow piece of mechanical infrastructure, and maintaining operations when repeated pulling of the stop cord by a single disgruntled community could seriously threaten ore delivery to meet contracts. Conveyors also come with a relatively wide right of way, accounting for the conveyor and a service road. This presents a potential scar on sensitive environments. A recent innovation, the rope conveyor uses a box shaped belt hanging from catenary cables with long distances of up to two kilometres between low footprint support towers.

BargingBarging of bulk ores remains a favoured start-up option where navigable waterways are available within a reasonable distance of the mine site. The low infrastructure cost of transporting long distances by water, and the low operating cost of the generally large unit of volume transported by barge, typically 5 000 up to 15 000 tonnes, makes this option attractive. Barging has been the default form of transport for Indonesian coal miners for decades. Only now that mines are becoming remote from

navigable rivers are more land based options, especially rail, receiving serious consideration. Rio Tinto Coal Mozambique recently proposed barging on the Zambezi River as their start-up transport option for the Benga and Zambezi coal mines in the Tete basin. The Mozambique Government initially rejected the Environmental Impact Study (EIS) over concerns about dredging impacting on fl ooding, and the fact that the fast fl owing Zambezi current, at around four knots, makes for another logistical challenge of a fast trip downstream loaded but a very slow return against the current.

Seasonality in rivers is also a big issue. Dry seasons and fl oods have the potential to disrupt the ore chain through reduced navigability, debris and shifting riverbed contours. Coal miners in Central Kalimantan, mining high quality coking coals located on the border with East and South Kalimantan, have been designing their barging operations to cope with several months of not being able to barge during the year due to low fl ows in the Barito River. Good logistics planning and stockpiling has made this successful at smaller tonnages

Barging of bulk ores remains a favoured start-up option where navigable waterways are available within a reasonable distance of the mine site.


but it is questionable as to how high production can go with such restrictions.

Transferring from barge to ship is the bottleneck in a barging chain. Proportionately, the addition of the largest costs per tonne occurs at this point. Methods range from simple fl oating cranes direct to ships hold (or even ships gear for smaller geared vessels) to loading via fl oating transhippers and even transhipping through shore based terminals. Adaro coal has been very successful loading large volumes of over 20 Mtpa of coal through fl oating cranes and transhippers over many years. Shore based terminals tend to be less dependent on weather conditions and load at higher rates and are therefore regarded as more reliable, especially for higher throughputs.

Lack of redundancyA recurrently increasing risk as the ore chain lengthens and mines become more remote, and serviced by less transport infrastructure, is the issue of redundancy. Over such long distances, community relations and social licence to operate become paramount in keeping the transport chain open and operating. Minor disagreements, if not well handled, can escalate with major consequences if there is disruption to the ore chain and no practical alternative due to the long distances.

Safety along the ore chain is a major consideration and generally well understood by the industry. A community member injured or killed on the chain will inevitably have dire consequences for operations.

Even issues of less apparent importance can lead to disruptions. The maintenance of community engagement and relations from the early planning, particularly in relation to land acquisition, through construction and operations attains equal importance with safety. The impracticality of ore chain redundancy and alternative routes over such long distances sees more engagement of mining companies with communities near the mine and those between the mine and the sea.

The inward supply chainWhile transport of the ore to market is the paramount transportation task, mines need supplies to operate. Mines and their workforces consume, among others, large quantities of fuel, explosives, food and spare parts. With mines becoming more remote and in less developed, lower infrastructure locations, the inward logistics chain is also a mission critical challenge. Combining the ore export and supply logistics chains seems an obvious solution to optimising cost

updated

effectiveness. However, the primacy of the ore delivery often means the push of inward supply onto secondary supply routes, increasing the indirect cost of production per tonne of ore.

ConclusionThe ore transportation task is set to remain an ever increasing challenge to mine developments in search of achieving the lowest delivered cost per tonne. As mines become more remote requiring longer transport routes, encountering more rugged terrain, and as a critical but potentially fragile link in the production chain, optimisation of transport chains will receive increased attention. We can most certainly expect further refi nement of transport methodologies and innovations as the 21st century progresses.

Andrew Keith is Aurecon’s Mining Infrastructure Leader. He is a civil engineer, with expertise in major industrial and mining infrastructure projects and was Aurecon’s Indonesian operations manager for twelve years.

You can contact Andrew at [email protected]

19

By 2031, 38 out of every 100 people in New Zealand will be living in Auckland, according to recent projects from Statistics New Zealand. Underground projects are important in delivering the effective new and upgraded infrastructure that will cope with such significant population increases. Aurecon has been involved in several tunnelling projects in New Zealand in recent years and is applying lessons learned, particularly around Earth Pressure Balance Tunnel Boring Machine (EPB TBM) technology, to the risk management approach in the USD 1.15 billion Waterview Connection Tunnels project, New Zealand’s largest transport project.

This article looks at our experience in tunnelling in Auckland and our thinking around managing risk and implementing effective tunnelling projects.

Project HobsonWhen Aurecon was engaged on Project Hobson, which involved

replacing the ageing sewer pipe that crossed Hobson Bay, with a three km-long tunnel and a new pump station in the Orakei Domain, we were aware that its success would enhance confidence in all the major tunnelling projects planned for the region following concerns over delays and cost increases on previous TBM projects.

The new tunnel and pump station would provide for population growth in the area and would also increase recreational opportunities in Hobson Bay. The extra capacity provided meant a reduction in wet weather overflows from this part of the network.

Using Earth Pressure Balance (EPB) TBM technology as part of the risk management approach Aurecon was able to successfully oversee the implementation of the wastewater tunnel. The use of this technology was a first in New Zealand.

Going underground Managing tunnelling risk in New Zealand

by Tom Ireland, a tunnelling specialist and Aurecon Technical Director


Ground conditionsThe prevalent ground conditions were East Coast Bays Formation (ECBF) comprising alternating beds of weak sandstone and siltstone which occurs throughout the Auckland region. The required horizontal alignment, however, presented variable ground conditions with the tunnel traversing two sediment filled channels in Hobson Bay.

Decision making and risk managementDuring the environmental assessment phase, the initial concept was a deep tunnel constructed in the ECBF; thereby avoiding the alluvial channels. To ensure the tunnel was wholly located in the East Coast Bays Formation would have required a pump station with excessive depth and committed the client to higher operating costs throughout the life of the facility. A more cost effective solution resulted from utilising EPB technology and lifting the alignment as high as possible, whilst remaining below the most adverse ground conditions - a basalt flow from Little Rangitoto on the eastern side of Hobson Bay.

To manage and share tunnelling risk Aurecon implemented a Geotechnical Baseline Report (GBR) on the project. This approach served to mitigate the risk of claims arising from bidders making overly optimistic interpretations of the data and using machinery unsuited to the ground conditions.

The implementation of the GBR on this project meant the risk profile adopted by each bidder was the same, and a bidder did not gain competitive advantage through elevating the owner’s risk.

The risk management process used also included a detailed TBM specification that was prepared so that the machines offered by each of the bidders adequately addressed the geological risks presented by the project.

The sticky nature of the ECBF material when excavated was the subject of an unforeseen conditions claim on a previous project in Auckland. On Project Hobson, the specification of an effective spoil conditioning system overcame this risk.

Aurecon provided full-time construction supervision services for the TBM works, and the tunnel excavation was completed three weeks ahead of programme.

Cost and programme certaintyProject Hobson proved that EPB tunnelling can be undertaken in Auckland with a large degree of cost and programme certainty.

Key success factors were the implementation of a GBR, which was an effective risk management tool,

and the selection of the tunnel alignment, which provided consistent tunnelling conditions.

The project received a Gold Excellence Award at the Association of Consulting Engineers NZ (ACENZ) awards in 2011.

Rosedale Wastewater Treatment Plant Outfall project The Rosedale Wastewater Treatment Plant Outfall project consists of a three km long segmentally lined tunnel that goes from the Rosedale Wastewater Treatment Plant to Mairangi Bay and into a 2 km marine outfall pipe before being discharged 2.7 km off shore (as compared to 600 m for the previous outfall pipe).

The Rosedale Outfall tunnel was also excavated with an EPB TBM. Although the tunnel was located entirely within the East Coast Bays Formation (ECBF), significant challenges during construction were posed by the downhill gradient, and some unexpected areas of extreme high pressure water inflows.

Whilst it is not uncommon for outfall tunnels to be subject to internal pressures due to losses through the diffusers, the Rosedale Outfall is an unusual situation, as the use of a long marine buried pipeline results in the HGL being 22 m above sea level through the offshore section of tunnel.

21

Dealing with the pressureThe internal pressure in the tunnel is up to 6 bar with a maximum net pressure of 2.5bar once the external water pressure is taken in to account. The design challenge on this project was to design a segmentally lined tunnel for this internal pressure. A traditional gasketted segmental lining has no tensile capacity across the joints and relies on external ground and water loads to maintain the compression in the gaskets. Steel fi bre reinforcement was preferred for the segments due to the superior durability, and the minimisation of damage during construction. However, this meant it was not possible to bolt the segment joints without using confi nement reinforcement, which had the potential to compromise the durability of the lining. The solution was to use the confi nement provided by the surrounding East Coast Bays Formation to resist the internal pressure (i.e. provide no reliance on the segmental lining) and to design the gaskets to provide a watertight lining.

The choice of the design alignment was such that the internal pressure is lower than the minimum in-situ horizontal principal stress in the East Coast Bays Formation rock. Testing for in-situ stresses was through the hydrofracturing technique. This too was a fi rst for Auckland East Coast Bays Formation, and advanced the knowledge of the local ground conditions.

Challenging construction conditions The construction phase presented unexpected zones of high water ingress, pressures and differing geology when intersecting the channelised zones of Albany Conglomerate, and heavily fractured faults and Parnell Grit. These conditions were far in excess of previous project experience with tunnels in East Coast Bays Formation, and provided an insight into the required mitigations for future tunnels.

The Rosedale Outfall project was a challenging project that included both design challenges, and unexpected ground conditions during construction. Despite the challenges presented, tunnel excavation was completed three days ahead of programme, and overall construction six weeks ahead of programme. This resulted in the project receiving a Gold Excellence Award at the Association of Consulting Engineers NZ (ACENZ) awards in 2011.

Applying lessons learned Aurecon has applied the lessons learned on Project Hobson and the Rosedale Outfall project to the risk management approach for the Waterview Connection Tunnels in Auckland. The USD 1.15 billion twin bore 3-lane road tunnel is New Zealand’s largest transport project. The EPB-TBM at 14.45m will be the largest in the southern hemisphere and the ninth largest in the world.

For the procurement of this project Aurecon worked with NZTA and utilised both a detailed TBM specifi cation and a Geotechnical Baseline Report as part of a Competitive Alliance procurement process. An interactive tender process that utilised alignment workshops and a two-envelope evaluation system allowed a competitive tender process without elevation of the overall project risk.

The project is due for completion in 2016.

You can contact Tom at [email protected]

Aurecon has now been engaged as Principal Advisor on Auckland’s next mega project, the City Rail Link, where the lessons of successful tunnelling globally and best practice riskmanagement will be applied.

Right Watercare Project Hobson, New Zealand


23

Urbanisation and expansion of the Drakenstein Municipality’s largest town, Paarl, 60 km north-east of Cape Town in South Africa, have resulted in a higher demand for water.

Paarl previously purchased approximately 95 per cent of its water supply from the City of Cape Town.

The town also had its own water supply scheme in place, which could have provided up to 25 per cent of the town’s annual water requirements. Due to a lack of treatment facilities, the mountain water source is hardly used at all – during 2005/6 only fi ve per cent of the town’s requirements were supplied locally.

A water supply management study conducted in 2001 found that there was a need for the municipality to secure its own reliable water source.

Apart from the obvious need for water treatment, the report showed

how the works could be constructed and operated at a substantial net saving, when compared to the alternative of purchasing the equivalent amount of water.

As the engineering consultant, Aurecon had to overcome signifi cant challenges in providing a solution for the water needs of the Drakenstein Municipality in an extremely sensitive environmental area.

Minimising environmental impact

The plant was designed with careful attention to minimising its visual impact.

The structure sits up to 5.5 m deep into the ground at places and has displaced approximately 1 500 tonnes of granite, almost half of which has been retained on site – either as cladding to the structures or as stone-pitching around the site – to allow for the building texture to closely approximate that of its surroundings.

The faces of the structures were staggered to lessen their visual impact and the landscaping of the site was designed to limit the visibility of the site from below.

Direct fi ltration processThe direct fi ltration process allows the plant footprint to be minimised, achieving a substantial capital cost saving over conventional treatment options of 15 per cent of the construction costs.

Direct fi ltration is not common in South Africa, and requires a more careful and specifi c design, particularly as there is no up-front sedimentation step to reduce the load on the fi lters. The chemical dosing requirements and fl occulation process are different to conventional systems where heavy and large settleable fl ocs are sought. The design at Meulwater Water Treatment Works facilitates a penetrating depth fi ltration of sturdier and smaller fl ocs, resulting in full utilisation of the solids storage capacity within the fi lter bed.

Brendon Theunissen, Project Manager at Aurecon, discusses how a novel treatment process has provided signifi cant cost savings for Meulwater Water Treatment Works.

Securing a reliable water source for Paarl’s increasing demands

Above left to right, BrendonTheunissen, Geoff du Toit and Laura Rowe


Coarser, deeper bedsGlobal trends have seen coarser and deeper beds with higher fi ltration rates than those typically used in South Africa.

At Meulwater, the fi lter bed is designed with coarse media at 1.2 mm effective size, and a deep bed of 1.5 m so that longer fi lter cycles are achievable. The coarser bed provides a higher nominal design fi ltration rate of 8.5 m/hour, with associated savings in construction costs.

Air scour and sub-fl uidisation backwashFilter cleaning is usually accomplished in South Africa by sequential air scour followed by reverse fl ow (backwash) to wash out the accumulated solids removed from treated water, which can lead to fi lter deterioration and costly rehabilitation work.

Combined air scour and sub-fl uidisation velocity backwashing enhances the backwash process. If the appropriate combinations of air and water fl ow are utilised, as has been done at Meulwater, a collapse-pulsing mechanism occurs in the bed, which is more effective at abrading fi lter media and loosening accumulated and adhering solids/fl ocs.

This feature is particularly important for the deep-bed direct fi ltration plant design at Meulwater, to ensure that the entire depth of the bed is cleaned with minimal loss of water.

Flexible designThe Municipality may in the future consider increasing the annual volume of Berg River water that is pumped into the Nantes Dam to supplement the natural infl ow. To allow for this, the fi lters were designed to accommodate conversion to dissolved

air fl otation-fi ltration units (DAFF process) by simple addition of the necessary white-water supply pipework, and provision of white-water production equipment.

The dissolved air fl otation process allows for injection of a side-stream into the fi lters of treated water that has been super-saturated with air at high pressure. A sudden drop to atmospheric pressure at the injection point allows for formation of micro-bubbles, which then attach to algae and chemically prepared fl ocs causing these to fl oat to and accumulate at the surface of the water in each fi lter as a fl oat layer of ‘scum’.

With a relatively small cost and without need for any construction work, an entire phase separation process can be incorporated into the existing plant in the future.

Declining rate hydraulic controlThe design of fi lters with declining rate hydraulic control is an uncommon feature in South African plants but has been shown that it can produce a better fi ltered water quality and provides capital cost savings.

The design of the process requires more comprehensive hydraulic modelling than for conventional systems, as the fl ow is not distributed evenly amongst the duty fi lters. Instead, each fi lter transmits a fl ow proportional to the total head provided and in equilibrium with the degree of clogging since the last backwash. The fact that a higher fl ow is not forced through the more ‘dirty’ fi lters prevents early breakthrough of attached fl ocs, while the cleaner fi lters transmit a controlled yet higher fl ow. Declining rate fi lters require a lower clogging headloss (about 30 per cent saving), as the

energy available to the cleaner fi lters is not ‘lost’ to a modulating valve as for conventional systems.

Enhanced dosing controlThe plant chemical coagulant dosing system incorporates an online mass fl ow metering system, which measures the actual mass of active ‘ingredient’ in the coagulant dosed.

The operators simply select the actual dose required and the automatic control system adjusts the dosing pumps to achieve that target whilst allowing for the actual plant fl ow.

This system allows greater accuracy of dosing control, with improved treated water quality and potentially signifi cant savings to the annual chemical cost.

Successful delivery of a novel solutionThe 8 Ml/d Meulwater Water Treatment Works was successfully commissioned in July 2012.

The enhanced process design deviated from conventional plants and was tailored specifi cally for the actual raw water to be treated.

You can contact Brendon at

Above Meulwater Water Treatment Works, South Africa

[email protected]

25

Remaining competitiveMinerals resource mining and development is a competitive business. None more so than coal mining, where operating companies are constantly reassessing their mine operations to reduce cost to remain competitive, and prospectors are looking for the edge to make their development succeed.

Diesel fuel, which is one of the most critical elements to most mines, is a major cost component of any coal mining activity. More than this, access to a reliable and economical supply can have a signifi cant impact on the cost competitiveness of the mine. At worst, interruption to supply can prove fatal.

Bulk rail transportation is often characterised by specifi c custom designed rail wagons to carry the bulk commodity. In the case of the rail transportation of coal, this can involve tippler (gondola) or bottom dump wagons. These wagons generally travel empty on their return journey to the mine. In effect, they deliver product to the port, and bring back fresh air.

For many years, a number of entrepreneurs have sought to utilise this backhaul space. The challenge for any rail operation is to utilise the backload more effi ciently, since the incremental cost of utilising the space is very low.

Through the application of technology recently developed by the US military, the backload can indeed be utilised more effi ciently, and potentially save the mining company a signifi cant amount each year.

The following case study illustrates how this technology can provide signifi cant savings compared with conventional road based supply of diesel fuel to the mine, or separate dedicated fuel trains.

In some instances utilising, backhaul space provides a logistics solution to otherwise diffi cult situations where road based transport or dedicated fuel trains are diffi cult to implement or sustain.

From an environmental perspective, by signifi cantly reducing road transport to the mine there is also a reduction in the carbon footprint ofthe mining operation.

The concept

Empty backhaul – the opportunityA typical coal mine, producing say three million tonnes of coal each year, consumes approximately 10 million litres of diesel fuel each year, depending on the mining methods employed and the type of mine. The transport of this fuel is typically by tanker trucks. With an average of 25 000 litres per truck, this constitutes around 400 return trips per year. Larger, B-double trucks, able to transport twice this amount per trip, would still result in 200 return trips per year.

From that same coal mine, assuming a 10 000 tonne payload train, 300 empty trains arrive each year which could have transported the diesel fuel. Just two 30 000 litre fuel bladders in one empty wagon on each empty train arriving at the mine would be suffi cient to deliver all the required fuel to the mine.

Requirement at the fuel depotWe acknowledge the adoption of this technology will require some changes as to how fuel is loaded and stored at site. Instead of having a fuel pumping station near the storage tanks, to enable tanker trucks to fi ll up, fi lling stations for the bladders might ideally be located close to the railway line. This may necessitate a change in fuel depot layout depending on the current location of the storage tanks.

Depending on the distance, it is possible to readily achieve such a change through a secure pipeline connection to a facility near the rail line, where prefi lling of fuel bladders can take place, in preparation of lifting into an empty coal wagon prior to its return journey to the mine.

Early planning of the logistics may substantially minimise the additional expense if storage tanks are to be located close to the facility near the rail line.

The fuel bladderCurrent manufacture of portable collapsible fuel tanks, commonly referred to as fuel bladders, is mainly for US military use. Made from heavy duty reinforced fabric, it is possible to roll the bladders into compact, transportable units. We propose to adapt this technology to the rail transport environment.

Fuel bladders can be manufactured in various sizes, up to 210 000 US gallons (approximately 795 000 litres). Coal wagons have a cubic capacity ranging from 70 to 100 cubic metres, which will accommodate fuel bladders in

by Alex Pey Aurecon’s Heavy Haul Rail Leader

Bladder technologyin backhaul


Internal rate of return best case scenario shows a net present value of

$4.3m, with annual savings in the order of $500 000 per annum

the 60 000 to 85 000 litres range, depending on the type of wagon and axle load limitations. The fuel bladder design will most likely result in two pillow-type bladders, each containing 30 000 to 42 500 litres, to be placed on top of each other in one wagon.

Tippler (or gondola) wagons, due to their design, are ideally suited to this application.

Bottom dump wagons often have lateral bracing inside the wagon to provide extra strength, which may preclude their use.

Lifting into the wagonThe proposal is that the lifting of the fuel bladders into the empty coal wagons is through a boom crane and guide ropes; facilitation of movement into and out of the wagons through appropriate pre-fi tted straps; minimisation of rubbing against the wagon sides through the use of readily removal and replaceable sacrifi cial material.

In situations where the rail line is electrifi ed, the lifting of the fuel bladders will need to take place in a neutral section, with overhead catenary wires removed.

Lifting out of the wagonRemoving the bladders from the wagons is not too dissimilar to the loading of the bladders. Similar equipment will be required.

The location of the unloading should take place as close as possible to the fuel farm servicing the mine. This will minimise any unnecessary transportation of the bladders.

At the mine – storing the fuelAt the mine site, reticulating tanks together through a manifold system will create a cost effective tank farm. Adding bladders will create additional storage capacity, if and when required.

A complete fuel system at the mine would include, in addition to bladder storage tanks, containment berms,

rainwater fi lter systems, protective sunshades, fuel transfer, metering and fi ltration equipment.

The possibility exists to quite readily expand such a facility to match any mine expansion or change in operations requiring increased fuel use. Also, the nature of the system easily lends itself to cost effective relocation in the event of mine closure, or a change to mining operations.

Returning the empty bladders to the supply pointThe bladders are fully-collapsible, easy to fold and therefore very easy to transport back to the point of supply. Empty and folded, several bladders would be able to fi t into one empty coal wagon, thus only sacrifi cing a small amount of capacity for the return journey. Keeping suffi cient supplies of spare bladders in the pool, means returning them will only need to occur perhaps once a week, or less

Worst case scenario

27

than 0.2 per cent of the capacity of a typical loaded haul. The bladders can be folded and stored in a modest space for the return journey.

The EconomicsOur example of a typical coal mine, producing say three million tonnes of coal each year, consumes approximately 10 million litres of diesel fuel each year, depending on the mining methods employed and the type of mine. In Australia, assuming a one way haul distance of 300km from the fuel depot, the transport of this input to the mine using B-double trucks, would cost in the order of USD 3 000 (all values are in USD) to $3 500 per delivery. Considering there are 167 deliveries required to supply the 10 million litres required annually, the annual delivery bill would total in the vicinity of $500 000 to $580 000.

The fuel bladdersOn the basis of 10 million litres of diesel fuel per year, if the bladders supply the fuel on a daily basis, with the empty ones returned on a weekly basis, a minimum weekly supply of 192 308 litres is required. With bladder volumes of 36 000 litres, a total of six bladders per week will be required. Allowing for a 15 per cent variation in supply requirements from week to week, as well as a number

of spares in the event of the loss or damage of a fuel bladder, we propose an investment of no more than 10 fuel bladders.

With each bladder costing in the order of $10 000, we thus propose a total investment of $100 000.

At the supply pointWith proper planning, the additional cost to locate the supply point close to the rail siding can be avoided. In that case, the only incremental cost would be relating to the additional time the train has to stop (if any) to load the fuel bladder, and the cost of lifting the fuel bladder into the train.

Looking at the time taken to load the fuel bladder, we note that rolling stock inspections regularly take place in the marshalling yard, which is often located close to the destination point of the product. The proposal is that the loading of fuel bladders be at these locations as this will allow concurrent activities to occur and thus eliminate the need for any additional time in the cycle. An added benefi t is that fuelling for the diesel locomotives in the marshalling yard also allows for the fi lling of the fuel bladders for the mine.

In terms of the cost to lift the bladders into the empty coal wagon, the

requirement would be a standard boom crane able to lift a full fuel bladder weighing 25 to 41 tonnes. Most rail yards would have such equipment already in place. However, in a worst case scenario, it may require calling in a mobile crane contractor to lift the bladders into the wagons.

On railThe empty coal wagons travel back to the mine and with minimal interruption to the cycle due to undertaking the lifting during yard time, the incremental cost on the rail will be negligible in the direction back to the mine. The return journey will require the sacrifi ce of one coal wagon to enable the return of the empty bladders to the supply point. At typical haulage rates of 1 to 2c per tonne km,we contemplate $250 to $600 incremental cost per week for the use of the coal wagon for the transport of the empty bladders.

At the mine siteThe incremental cost associated with unloading the bladders at the mine site would also be minimal. Many mine sites have mobile cranes available to use once a day to unload the fuel bladders – a process that would reasonably take less than an hour. The unloading process may even take place while the train is waiting for a scheduled path back to the port, or

The best case scenario shows a net present value of $4.3m, with annual savings in the order of $500 000 per annum

$56k

$100k

$100k

$580k

$4.3m

Acquisition of fuel bladders; Worst case scenario involves also some investment in loading equipment

Opportunity cost and loading delays; Worst case scenario involves also some ongoing contract loading expense

Replacement of bladders every seven years

Based on $3K to $3.5K per return trip by B-Double

Discount rate of 8% and 15 year project life

Worst case Best case

Initial capital investment $350k

Ongoing operating costs (p.a) $281k

Recurring capital $100k

Savings in road haul cost $500k

Net present value $1.4m

all values are in USD


when there is an idle moment before or after the coal loading process.

On some occasions, this may not be possible, so it may be necessary to factor in an allowance for some delays in the cycle. If this activity occurs only once a week, then this potential time delay will impact 52 out of 300 services (17.3 per cent), by say one hour. With typical cycle times for a 600km return journey in the order of 16 to 20 hours, the delay would represent a fi ve to six per cent increase in the cycle, for those 52 services. The overall impact would be fi ve to six per cent multiplied by 17.3 per cent or 0.9 to 1.1 per cent. This would represent a potential fi nancial impact of $81 000 to $198 000 if every loading of the bladders delay the trains, and the rail operator passing on all the delay costs back to the miner.

It is not unreasonable to assume that trains have to wait for a return path back to the port, so delay impact may be minimised. For this assessment, we assumed approximately 50 per cent of loading events cause delays that pass back to the miner, and so assumed an impact of $40 000 to $100 000.

We have also assumed a worst case scenario involving the investment in loading equipment such as a mobile crane in the order of $250 000.

Storing the fuel may provide benefi ts for the mine as it no longer has to provide storage tanks. The bladders effectively are the fuel storage containers. Savings associated with not having dedicated storage tanks on site can go into providing adequate bunker facilities, manifold systems, and weather protection for the bladder tank farm at the mine. We have assumed nil incremental cost for the storage of the fuel on site.

SummaryUnder the worst case scenario, the economics of this strategy still stack up. The annual savings are in the order of $200 000 to $220 000 taking into consideration the investments in bladders and loading equipment. The net present value (assuming a 15 year evaluation period and an 8 per cent discount rate), is still a very healthy $1.4m.

The expectation is the economics will be even more favourable for mines more remote than the assumed 300km base case, or where the road network is not well developed. The added security of having the fuel in the train may provide additional benefi ts for the mine, with increased surety of supply.

Variations to the themeBy no means are we suggesting that the use of bladders inside coal wagons is the only way forward with this idea. As noted previously, the structural design

of bottom dump wagons, with their internal support, makes it diffi cult to use the empty space for full fuel bladders.

Alternatives to the theme could include placing the fuel bladders in fl atbed wagons with container skeletons. These wagons can then also transport the empty bladders back to the point of supply. The use of container skeletons also facilitates the loading and unloading of the bladders at both ends of the cycle.

All in all, the economics point to a case worth pursuing for individual miners. The ongoing savings in fuel supply costs is not insignifi cant.

Constantly seeking to innovate, we are committed to working closely with our clients to deliver out of the box thinking on some of the world’s most complex and important development projects.

About AlexAlex Pey is Aurecon’s heavy haul rail leader and has a long history in railway accounting and railway economics. He has an expert understanding of coal rail development in Queensland and the coal logistics chain. He was the author of Queensland Rail’s Coal Rail Infrastructure master plan, which contemplates development and growth of the QR coal rail network. Alex has considerable experience in planning, designing and costing rail logistics supply chains.

You can contact Alex at [email protected]

Below Fuel bladder in a bund (Image courtesy of US National Guard)

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Expertise

Airports Airports are multi-faceted transport hubs and retail operations, requiring a range of expertise rarely available within one consultancy. Aurecon is a total infrastructure provider, developing world-class solutions integrating transport hubs and the built environment.

Asset managementOptimising the value of an asset portfolio is critical for our clients’ performance, continuity and profi tability. Our management and technical resources assist investors and business operators to optimise returns on new and existing assets.

“Within our business culture, we link our competencies and technical knowledge in an organic and strategic way. Many of our competency leaders are at the cutting edge of knowledge and technical development. Aurecon continues to invest the time and resources needed to create competencies that are the engine-room that powers client success.”

Peter Turner Head of Competencies at Aurecon


Building structuresOffering world-class structural design, Aurecon has built a reputation for technical excellence and innovation. We provide a diverse range of analytical and practical skills, delivering sustainable, economical and buildable solutions that meet the needs of our clients.

Bulk material facilitiesThe design of a bulk material facility requires specialist knowledge relating to the product being handled. Having designed seven of the largest facilities in the world, Aurecon’s world-leading multidisciplinary service is continually called upon by our key clients.

Building sciencesAurecon offers building sciences expertise to complement our core building services and building structures capability. We offer integrated expertise in niche areas of acoustics and vibration, environmental modelling, ESD, façade engineering and fire safety engineering.

Bulk water and damsAs experienced designers of dams, reservoirs and bulk conveyance systems, we provide whole-of-life expertise, from network planning to design and construction monitoring, analysis, operational and asset management, and rehabilitation.

Building servicesOur team designs engineering systems that bring buildings and structures to life so they function efficiently, economically, safely and sustainably. Our aim is to design and deliver safe, comfortable and environmentally-friendly buildings for both our clients and the end users.

Business and infrastructure advisoryOur clients are seeking more than technical solutions. We support their performance with strategic infrastructure planning, business consulting, risk management, procurement advice and training and development.

Environmental and community planningOur experts find the balance between economic growth, social development and protecting the environment. We guide our clients and stakeholders through positioning, planning, approval, design, construction and operation.

Ground engineeringOur renowned group of specialists provides comprehensive ground-related infrastructure services including investigation, laboratory testing, design of underground infrastructure and provision of specialist construction supervision.

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ManufacturingWith a reputation for innovation across process industries, we deliver cost-effi cient plant solutions and production improvements for our clients. All engineering disciplines are part of our service offering including process, mechanical, electrical and automation.

Mining infrastructureOur clients value Aurecon’s understanding of the complexities and disciplines required to deliver major mining infrastructure. We plan, design and manage the construction of world-class materials handling facilities and supporting infrastructure.

Information and communication technologyAurecon supports communication and technology companies, providing total management and design services associated with the rollout of new and expanded networks. We help our clients create information services of the future.

Ports and coastalDelivering seven of the ten largest coal ports in the world, we have an outstanding track record in port and coastal design. Our expertise includes front-end studies, transportation chain EPCM, intermodal hubs and seaboard bulk materials handling facilities.

Land infrastructureAs communities grow, the capacity of new and existing infrastructure is of increasing importance. Aurecon’s infrastructure specialists work closely with our clients to identify non-traditional approaches and deliver sustainable solutions.

Power generationAurecon delivers effi cient and reliable power generation solutions to our clients. Our technical advisory, asset management and engineering design skills are used to enhance existing assets and develop, design and commission new infrastructure.

Programme and project managementOur comprehensive capabilities in all project delivery models assure our private and public sector clients of project outcomes whether they are business, planning, transactional, delivery or operationally orientated.

Power transmission and distributionRecognised as a market leader, Aurecon has over 40 years’ transmission and distribution experience. Using leading edge technology, we design transmission lines, plan systems, design substations and optimise assets.


RailWith over 30 years’ experience delivering rail infrastructure design, Aurecon offers the complete range of design services across all phases of rail project delivery. Our expertise includes heavy haul rail, freight rail, passenger and urban networks, and light rail.

Transport systems and logisticsAurecon is a leader in the planning, design and delivery of operational infrastructure for roads and rail. Aurecon’s HUB-id program integrates human behaviours to drive outcomes in land use form and transport function.

Renewable energyAs a market leader in renewable energy, our clients benefit from our experience in wind, solar, hydro and bioenergy technologies. Partnering with leading research institutions, we apply innovative solutions to create value for our clients.

Water and waste water treatmentAurecon’s team of water experts deliver tailored treatment solutions for all aspects of the water cycle, from municipal and industrial wastewater to desalination, recycled and potable water treatment, from planning to operation.

RoadsAurecon supports the planning, design and delivery of roads — from rural access to complex freeways, toll roads to system interchanges. We have designed thousands of kilometres of roads worldwide, integrating ‘green roads’ and sustainability into our methodology.

Water resources managementAurecon has been a world-class practitioner for three decades. We have expertise in multi-user trans-boundary river-reservoir systems, complex urban catchments, and state-of-the-art modelling. Our clients value our focus on sustainability, equity and efficiency.

Expertise

Sustainability Aurecon is committed to sustainable development - meeting today’s needs without compromising future generations. We work with our clients to establish and implement sustainability strategies across their business, advising on the sustainable performance of assets, infrastructure and projects.

UrbanisationIncreasingly, people are moving to cities. Well planned, efficient hard and soft infrastructure solutions are critical parts of the urbanisation jigsaw. Aurecon addresses these complex issues with our in-depth engineering and urban planning knowledge, combining this with our economic, social assessment and financing expertise.

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Aurecon is engaged as a key member of the design team to deliver the world-class building which will be the headquarters of the South Australian Health and Medical Research Institute (SAHMRI) in Adelaide, South Australia.

The project targets ambitious design and sustainability outcomes, as well as a unique integrated structural façade system. To achieve these interrelated goals, critical integration of building function and form were brought together in the very early stages of the design process, fostering a collaboration of ideas and thoughts from all members of the design team.

Aurecon structural engineers are advocates in promoting a design philosophy around “learning to speak the language of architects”. For the SAHMRI project, the Aurecon team embedded their thoughts and ideas early and worked closely with project architects Woods Bagot on the creative vision for the building. This early engagement created a pathway leading ultimately to the construction of a functional and iconic building that delivers on a key project vision: “A thingof the world in Adelaide”.

SAHMRINiko Tsoukalas, Aurecon’sTechnical Director, Buildings, discussesturning architectural creativity into innovative structures

Below Urban planning sketch


Below Render of SAHMRI (image courtesy Woods Bagot)

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Flower column construction methodology – step by step 1. Construct level three (plaza level)

2. Construct the flower column bases (concrete and grout plinths)

3. Construct the flower columns themselves (steel)

4. Construct level five concrete slab supported via temporary specialist support structure to minimise or eliminate load on the flower columns

5. Construct level six

6. Prior to beginning level seven construction, the flower columns where “ready” to carry the load of the building and as such a further, detailed process was undertaken, known as the ‘release’ process

7. Simplistically put, this process removed the load from the temporary support structure and transferred it into the flower columns and required the careful collaboration of key construction trades and project engineers

8. To undertake the release, in addition to specialist movement monitoring, the University of Adelaide was engaged to undertake monitoring of the load transfer and ensure that the project engineers at Aurecon were satisfied with the transfer process

NB. The monitoring process with the University of Adelaide utilised 28 “strain gauges”, that were connected to customised software systems that converted the loads instantaneously onto a computer screen that allowed Aurecon engineers to review and advise the construction team on the status of the release process

9. The “release” was undertaken in a total of four working days, as opposed to the original scheduled eight working days to the satisfaction of all

Aurecon suggested that by finessing the geometry of the column locations to the upper floors, the required 36 columns could be reduced to just six main support locations at plaza level, by the use of what has been colloquially termed as “flower columns” (refer to sketches).

These innovative structural elements achieve the requirement of avoiding a ‘forest of columns’ and have reduced the support steelwork to around 250 tonnes. Critically, the design solution enhanced the overall architectural design by creating the illusion of the building “floating” above the ground plane.

Flower columns – opening up interior spacesThere are six flower columns in total that support the majority of the building mass. The columns consist of four or three arm configurations with differing geometry (refer to sketch far right).

The flower columns are a maximum of 500 mm in cross section and vary up to 15 metres in length. The columns themselves emerge from Level three and reach into Level five. Level four is supported from the flower columns. However, this design requirement placed additional complex loading arrangements within the flower column design.

At their main junction point at the base/plinth, in their most challenging load-bearing location, the columns support a total of 38 000 kN. To put this in context, this load is the equivalent of approximately 2 500 family cars stacked one on the other. While for each of the individual column arms at the same location, the supported, total vertical load is approximately 10 000 kN, which is the equivalent of approximately 650 stacked vehicles.

The flower columns are not vertical and sit on varying angles to the horizontal, between 75 degrees and 40 degrees from the horizontal. The raking nature of the flower columns means that they impart a permanent horizontal load at Level five and Level three which must be dealt with in a careful balance of force distribution through the structure and within the lift and stair cores.

Above Flower columns transfer load modelling


The column “arms” transfer loads via the use of “cruciform” connections. These connections are designed to carry the load required via “bearing” only, and not through the use of bolts, to enable them to be as slender as possible. The bearing surface zone is accurate in terms of surface fl atness to within +/- 1 mm. The column bases/plinths are made of concrete and very high strength grout and have a complex array of force transfers in multiple directions.

Across the SAHMRI project, Aurecon is currently undertaking the structural, civil, façade, traffi c, geotechnical, wind and specialist vibration engineering design services. In a joint venture with consultants Norman Disney Young, Aurecon is also providing electrical, information and communications technology, fi re and vertical transportation engineering consulting services for the delivery of the 25 000m2 SAHMRI medical research institute.

Scheduled for completion in 2013, the Institute will house up to 675 researchers undertaking research that will foster innovation and improvements in health services, and lead to improved health outcomes for the whole community.

You can contact Niko [email protected]

The integration of architecture and structure has “fostered innovative thinking” for SAHMRI design. The Aurecon team hopes it will be a legacy that will continue to inspire and remind people working in SAHMRI that innovative and collaborative thinking is required to create the eureka moment leading to a world fi rst cure for cancer.

Above Interior render of SAHMRI (image courtesy Woods Bagot)

Above fl ower column concept sketch

Above Flower column concept sketch

37

The increasing rate of urbanisation in recent decades has seen an accelerated trend in construction of tall buildings worldwide.

According to the Council on Tall Buildings & Urban Habitat (CTBUH), there were some 700 buildings worldwide in 2011 exceeding 200m in height, meeting CTBUH’s defi nition for tall buildings. This number is expected to increase to around 800 by the end of 2012 and to over 900 by the end 2013, with an accelerating trend thereafter.

The majority of these buildings are being built in the Asian continent. Over the last 20 years or so, the centre of gravity of world tallest has moved from downtown Chicago and New York to places like the land corridor along Sheikh Zayed Road in Dubai and the Pudong district in Shanghai. However, the trend in tall buildings construction is not limited to their quantity and geography.

In the last decade or so, there has been a signifi cant shift in the architectural form of tall buildings and aspirations for their increased amenity, performance and sustainability. The conventional glass box edifi ces are being replaced by intriguing geometries of twisting and leaning towers. The building envelopes are being turned into environmental fi lters (in the form of layered façades, perimeter atria, and the like) profoundly changing the ventilation, thermal and lighting performance, and ultimately environmental sustainability, of modern tall buildings.

Buildings such as Shanghai Tower (which is due for completion in 2014) embody multiple aspirations of height, architectural form, high performance, and environmental sustainability in a tall building. Furthermore, in the developed world, there is a fast declining rate in availability of “greenfi eld” sites for tall buildings in CBDs.

Therefore, opportunities are mostly around refurbishment or redevelopment, with the latter often involving suboptimal land sizes and development restrictions on issues related to over-shadowing, heritage integration, public precinct access, ect.

Aurecon is currently designing the offi ce tower 5 Martin Place, Sydney, Australia, with Grocon. The project incorporates a key heritage building (affectionately referred

to as the “Money Box” building for decades) with a new offi ce tower being designed as an inverted L-shaped structure with its top 10 stories cantilevering up to 22m over the undisturbed heritage building beneath.

These all make tall building engineering an increasing multidimensional process demanding an integrated design approach.

Effi cient design: Structural engineers have a vital role to play in integrating overall projects aspirations in their design of tall buildings. The design choices made by structural engineers often have a profound impact on cost, amenity, constructability, and sustainability of tall buildings.

Aurecon’s design of the World Tower in Sydney is an excellent example of effective implementation of this approach. At a height-to-base ratio of around eight, World Tower is one of the most slender tall buildings in Sydney’s CBD. Being a residential tower, it also has a relatively small concrete core. Yet by clever integration of diamond-shaped outrigger walls in the dividing walls of the apartments, the tower columns have been engaged to resist 80% of lateral loads (with the remaining 20% resisted by the core) without any tie down mechanisms to resist overturning and without the need for any additional dampers to mitigate wind motions.

Any interference of outrigger walls with the differential axial shortening behaviour of the tower has also been effectively eliminated by innovative short term release details (form of fl at jacks) that were fully grouted once creep deformation of the building had largely taken place (around two years after building completion).

Of course the structure of a tall building has to be safe and cost effective. But an integrated design approach should also include buildability and minimisation of construction risk in the design process. Issues such as fabrication, transportation, temporary strength and stability, erection sequence and safety, and control of movements during construction should be considered as well as in-service performance, safety under extreme events, and operation and maintenance strategies. This is a “cradle-to-grave” approach to structural engineering. The behaviour of the structure during

Integrated approachin structural designof tall buildings

by Kourosh KayvaniAurecon’s Structures Leader SHANGHAI TOWER

LANDMARK EAST, HONG KONG

Aurecon Thinking in actionAurecon Thinking in action

construction is complex and hence needs to be analysed and studied in detail. By building and analysing a simulated (fi nite element) model, we can overcome the unknown, and test and de-risk the building before it is built, without compromising its technical integrity.

Choice of steel, concrete or composite construction and the level of offsite fabrication of structural elements is critically dependent on the location and market condition, as well as the builder preferences in terms of access to technology and programming advantages. In high labour cost economies such as Australia, minimising site labour can be a key design criterion. This can make prefabrication, either in steel or precast concrete, the preferred approach.

As structural engineers for the recently completed 260m tall Brookfi eld Place in Perth, Aurecon worked with Brookfi eld Multiplex on this project to develop a unique composite-steel solution that is fast and effi cient to build. The structural design includes many measures to allow the effi ciencies rendered by combining off-site manufacturing and on-site construction with due regard to the environmental conditions during construction (such as wind limiting crane operations). While the basement level fl oors were constructed in concrete, the 47 fl oors were designed in steel. Architecturally expressed steel mega braces were also used to mitigate wind torsional response arising from the side core position.

Speeding the advancement of the structure is front and foremost in the mind of tall building builders. Therefore, advancement in offsite fabrication and construction process has heavily infl uenced the engineering associated with the structural design of tall buildings. There are even moves towards modularisation as demonstrated by pilot projects in China and USA.

However, the core values of simplicity in detailing and construction still remain valid. Simplicity is fast. If the solution is complicated, the time to construct it is normally long. Understanding the range of likely builder’s preferences and its effect on elements such as core construction and edge formwork shapes are also important. Forward planning and imbedding fl exible measures on architectural and mechanical, electrical and plumbing (MEP) integration issues (eg, MEP penetrations in the core) speed up the design

coordination process and saves time in construction. On the 45-storey offi ce tower at 161 Castlereagh Street, Sydney, Australia, Aurecon sought to simplify complicated junctions, maximise repetition in design, and implement prefabricated reinforcement in the footings and tower fl oors. We also worked with Grocon to use sustainable concrete mixes with a high percentage of recycled aggregate and cement replacement. Extensive interpretation of material testing (of elastic modulus, shrinkage and creep performance) and ongoing monitoring of construction have been utilised to confi rm our design assumptions for this novel material.

Understanding local construction techniques and the relative costs of labour and materials is essential. Solutions which are economic in high labour cost locations such as Australia will not necessarily translate to locations like Vietnam or Africa. For example, in our design of the ICON House building in Accra, Ghana, and ACB Square, Vietnam, extensive use of cast-in place concrete reinforced concrete construction was made refl ecting the relatively lower cost of labour/time against material/high skills.

Product availability (eg, scarcity of mechanical couplers) and variability construction material (associated testing required) were also key considerations in achieving a safe yet economical outcome for these projects.

Emergence of performance-based design methodologies have generated opportunities to design more innovative tall buildings that achieve optimum outcome for multiple performance objectives (collapse prevention, life safety, immediate occupancy, and full functionality/serviceability) under fi re and earthquake events.

Aurecon is part of a global working being formed by the Council on Tall Buildings and Urban Habitat (CTBUH) for developing revised guidelines for seismic design of tall buildings. Recently, Aurecon used performance-based approach to design innovative low-damage aseismic structures in New Zealand (such as the Te Puni building in Wellington), which has generated much interest in the market place in the aftermath of the devastating earthquakes of September 2010 and February 2011 in Christchurch.

You can contact Kourosh at [email protected]

5 MARTIN PLACE WORLD TOWER BROOKFIELD PLACE 161 CASTLEREAGH ACB SQUARE TE PUNI

39

Keeping supplies fl owing to meet growing demand in theoil and gas industry by Ruben Nielsen, Senior Marine Structures Engineer, Aurecon


Keeping up with growing industry demand by expanding, upgrading or building a new supply base is a challenge executives charged with keeping supplies fl owing to the offshore oil and gas platforms know well.

It takes many years to develop and operationalise a new supply base; in some cases it has taken up to ten years from identifi cation to completion.

In an industry that demands reliability and effi ciency, such timeframes mean years of reliance on existing facilities operating above their capacity along with the associated risks, as oil and gas fi elds continue to expand.

This discussion takes a look at what factors lead to the successful development of marine supply bases.

Understanding the requirements Organisations that successfully meet the challenge of supplying the offshore oil and gas platforms acknowledge that an advisor can bring to a project enhanced understanding of what is required. Experience shows the best outcomes tend to come when the project owner engages an advisor at the outset of the development process.

Skilled advisors bring resources and skills in project planning and logistics, site selection, geotechnical investigations, infrastructure design

and construction management. Working together ensures project drivers are correctly determined from the outset. It supports a good understanding of the base operating principles, servicing requirements of offshore oil and gas fi elds, phases of oil and gas fi eld exploration and production, growth in number of platforms over the design life of the supply base. Furthermore, it helps mitigate risks throughout the project development process and the delivery of innovative solutions while staying in schedule and budget commitments.

Project driversProject drivers typically stem from the requirement to meet future demand of new oil and gas fi eld developments or expanding offshore oil and gas activities.

Drivers may also include the consolidation of multiple supply base functions and facilities, operational improvements, modernisation in terms of both effi ciency and safety features, and freeing from constraints on expansion caused by port congestion or close proximityto communities.

Generally, the new facility needs to be dedicated to providing services to the oil and gas industry.

Site selectionSite selection is a critical phase in the development. It requires a balance in choosing a site close to supporting services and transport

infrastructure, and one close to the oil and gas fi elds for maximum effi ciency regarding sailing distances.

For example, the site selection for the Darwin Marine Supply Base is next to the East Arm port facility, located near the city of Darwin.As Darwin is already an established oil and gas service centre, the new base will benefi t from the diverse capabilities of local supporting industries and existing infrastructure.

Proximity to a port city provides strong supply chains through existing transport and intermodal facilities, well-known logistics providers and service companies, established port infrastructure, manufacturing and fabrication capabilities, available skilled labour, waste disposal services and health, education and training services.

Port authorities and governments would probably be supportive of a new supply base: particularly when it supports the development of new major oil and gas projects and transfers supply vessels from existing port berths, allowing growth in the Port’s general cargo throughput.

Many ports have both strategic vacant land suitable for development and allowances for future expansion. A new supply base provides growth in local supporting industry, employment and business tax and port revenues.

41

However, existing ports are not always the answer to site selection. This is especially true in some Asian countries due to port congestion, particularly those ports with fishing fleets. Congested marine traffic into the port would hinder vessel movements, and lack of land availability would restrict future expansion. In some cases, it would be necessary to separate onshore and marine components owing to space constraints. Identification and assessment of potential alternative sites would first target sheltered before open sea coastline locations. Any site not in an existing port will require extensive studies into geotechnical conditions, met-ocean conditions and bathymetry. In many cases, an undeveloped site will require road works, breakwater construction and dredging for a navigation channel. These components add significant complexity and expense to the project.

Operating principles of a multi-user supply baseKey operating principles for a multi-user supply base arise from the need to provide integrated services to oil and gas companies.

Facility design would provide multi-user access to four to six berths, available 24 hours a day. There would be priority access contracts drawn with the primary oil and gas company, on which the base relies for its major

revenue stream. Selling spare berth capacity to other customers would keep berth occupancy rate at 80 to 90 per cent.

Other operating principles would include allowing multi stevedore access as required by customers; having third party service providers for drilling mud, waste disposal and transportation logistics; maximising utilisation of base equipment such as cranes; and minimising fixed operating costs.

Achieving berth availabilityEssential to the success of a supply base is quick and efficient vessel turnaround and minimisation of waiting times of arriving vessels. The target for vessel turnaround time is about 12 hours.

Berth availability and quick vessel turnaround are achieved by having dedicated cranes at each berth; arranging staging and preloading of cargo at the berths; ensuring necessary loading capacities of liquid mud, water, fuel and cargo; and pre-booking and confirming arrival and departure times.

Other key activities for quick turnaround include interface management with the Port Authority and Harbour Master for vessel movements, and maintenance of all safety and operational critical systems.

Provision of equipment and servicesPlanning for the supply base requires close contact with the end operator, to ensure the integration of activities and base functions.

Shore base operations require the inclusion of port services, cargo handling equipment and services, materials management, labour hire, offshore container management, lifting and rigging equipment, inventory management, drilling tube and pipe management, waste management and provision of office accommodation.

Cargo storage and consolidation facilitiesLayout design of the supply base must consider numerous components for cargo storage and consolidation.

The ideal configuration for the marine components of the base is land backed berths to facilitate efficient movement of cargo.

Material and cargo storage requirements include drilling mud plant, bulk material plants, undercover warehouse storage, open laydown storage, drill pipe storage areas, Cargo Container Unit (CCU) storage areas, hazardous waste storage, storage for gas cylinders, chemical and lubricant storage,


consolidation area for offshore construction materials.

Offshore oil and gas project requirements The development of offshore oil and gas projects may have specifi c requirements. It is best to consider these early in the planning phase and build them into the supply base design. They may include a material offl oad facility (MOF) for offl oading and consolidation of heavy construction components using RoRo and LoLo type berths; pipe laying support services; rock outloading facility for marine pipeline protection; marine fuel bunkering; dry-docking services for maintenance, repairs and classifi cation inspections; provision for Customs Services to process international vessels; quarantine and inspection services.

Transport servicesA supply base relies on well managed and integrated transport services to deliver supplies and remove the waste brought back from the offshore platforms. It is important to plan and provide for effi cient cargo fl ows in and out of the base and this requires a truck marshalling area, space for road transport consolidation, logistics for road and air freight services, security gates controlling each vehicle entering and leaving the base.

Compliance managementCompliance management is another activity that needs to be included in the supply base services. This includes managing compliance with government and relevant industry regulations; HSE, lifting, transport and waste management plans; quarantine and customs regulations.

About the author Ruben Nielsen is a Senior Ports and Marine Structures Engineer experienced in marine facilities, terminals, offshore jetties, small craft harbours and civil infrastructure.

While in Bangkok in 2011, Ruben was the Marine Structures Lead on the Chevron Thai Shore Base project located in Ban Bang San, Thailand; and Marine Structures Engineer for the Dawei Sea Port development in Myanmar.

Prior to this, Ruben was the Marine Lead for a group of eleven engineers and designers on the offshore marine structures for the USD 2.5b Hay Point Coal Terminal Stage 3 Expansion project.

Aurecon’s expertise The planning and development of a new supply base is complex and requires dedicated planning and engineering skills.

Aurecon can provide the necessary studies and engineering required from the initial planning and approval phases, right throughto detailed design of the base and associated infrastructure and services and onto the construction phase.

We work directly with the project team assigned with developing a supply base. In some cases that team can be a group of core people from a supply base operator company wishing to develop a multi-user supply base or a project team in the oil and gas company requiring a new base for their own operations, as in the case of Chevron Thailand and their Ban Bang San supply base project.

You can contact Ruben at [email protected]

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Registered office, Singapore

152 Beach Road #22-02Gateway EastSingapore 189721T +65 6256 6188E [email protected]

Registered office, Australia Melbourne

Aurecon CentreLevel 8, 850 Collins StreetDocklands VIC 3008 AustraliaT +61 3 9975 3000E [email protected]

Registered office, South Africa Tshwane

Aurecon Centre Lynnwood Bridge Office Park 4 Daventry Street Lynnwood Manor 0081 South Africa T +27 12 427 2000 E [email protected]

About Aurecon Aurecon provides engineering, management and specialist technical services for public and private sector clients globally. The group, with an office network extending across 25 countries, has been involved in projects in over 80 countries across Africa, Asia Pacific, Middle East and the Americas and employs around 7 500 people throughout 11 industry groups. We seek to foster human achievement in all aspects of our work.

Aurecon offices are located in:Angola, Australia, Botswana, Brazil, China, Ethiopia, Hong Kong, Indonesia, Lesotho, Libya, Malawi, Mozambique, Namibia, New Zealand, Nigeria, Philippines, Qatar, Singapore, South Africa, Swaziland, Tanzania, Thailand, Uganda, United Arab Emirates, Vietnam.

For more information please visit www.aurecongroup.com

Aurecon South Africa (Pty) Ltd is a certified Level 3 BBBEE contributor.

The Aurecon Group is made up of a number of separate legal entities operating across diverse jurisdictions. Not all those entities provide services to clients.

©2012 Aurecon

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360 degrees magazine issue 6