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VOLUME 25, ISSUE 1 | JANUARY/FEBRUARY 2020

In this issue: Gearing up for BULK2020 Choosing the right conveyor belt How to sell bulk handling solutions

FAST, ACCURATE, AND LOW DUST. THE PREMIER TECH PTF IS A GAME CHANGER.


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CONTENTS JANUARY/FEBRUARY 2020

15

18

24

36

9 thyssenkrupp to deliver world’s largest rail mounted stackers and reclaimer for South Flank

15 Concetti launches two-in-one bagging system

34 Supporting supplier success

16 New year, new name for Kockum’s Bulk Systems

36 Working smarter and harder

10 Belt splicing now a trade in WA 10 Global sugar market faces largest supply deficit in five years

18 The common causes of ceramic lagging failure 20 Sensing innovation

38 Good vibrations 40 Conveyor skirting explained

12 Port of Melbourne unveils 30-year plan

22 BULK2020 leaps forward

42 The only thing harder than selling bulk handling solutions

13 CBH makes largest annual investment into infrastructure network

24 Pumping up gold production rates at Greenfields Mill

48 Investigation of loads acting on flow isolating gates in bulk solids storage bins

14 Rema Tip Top wins contract to deliver 50km conveyor

28 Building blocks for a global foundation

54 BULKtalk: Choosing the right belt – Part 1

31 Supporting supplier success

58 ASBSH Member Profile: Priscilla Freire

15 Measuring the mass flow

32 Moving grain stockpiling forward

www.bulkhandlingreview.com

VOLUME 25, ISSUE 1 | JANUARY/FEBRUARY 2020

In this issue: Gearing up for BULK2020 Choosing the right conveyor belt How to sell bulk handling solutions

NEW YEAR, NEW NAME FOR KOCKUMS BULK SYSTEMS It has been almost two years since Canadian company Premier Tech acquired Australian pneumatic conveying and powder handling company Kockums Bulk Systems (KBS). Australian Bulk Handling Review sat down with KBS Managing Director, Francois Steyn, to find out what the company has in store for 2020 and what its new name will be.

FAST, ACCURATE, AND LOW DUST. THE PTF IS A GAME CHANGER.

For the full story, see page 16.

4 І Australian Bulk Handling Review: January/February 2020


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AUSTRALIA

EDITORIAL

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REVIEW

Improving innovation 11-15 Buckhurst St South Melbourne VIC 3205 T: 03 9690 8766 www.primecreativemedia.com.au Publisher Christine Clancy E: christine.clancy@primecreative.com.au Editor William Arnott E: william.arnott@primecreative.com.au Business Development Manager Luke Ronca E: luke.ronca@primecreative.com.au Client Success Manager Janine Clements E: janine.clements@primecreative.com.au Design Production Manager Michelle Weston E: michelle.weston@primecreative.com.au Art Director Blake Storey Design Kerry Pert, Madeline McCarty Subscriptions T: 03 9690 8766 E: subscriptions@primecreative.com.au

www.bulkhandlingreview.com The Publisher reserves the right to alter or omit any article or advertisement submitted and requires indemnity from the advertisers and contributors against damages or liabilities that may arise from material published. © Copyright – No part of this publication may be reproduced, stored in a retrieval system or transmitted in any means electronic, mechanical, photocopying, recording or otherwise without the permission of the publisher.

In the 1980s, films like Blade Runner and Back to the Future pondered what the future might look like. With 2020 hindsight, it’s clear that we haven’t got flying cars yet, but the technology is creeping closer every day, with Uber announcing it will start test flights of its air taxi services this year in Melbourne and planning to move to commercial operations by 2023. We’ve also seen the incredible rise of the smartphone and the internet of things which have changed how millions around the world connect and do business, and with 5G on the horizon it looks like things will accelerate further. All of these technological breakthroughs have required innovative engineers and organisations that were willing to take the plunge and try something new. Supporting new technologies is key to ensuring the bulk handling industry can continue improving its productivity and safety. This is why Australian Bulk Handling Review (ABHR) is proud to be part of the annual Bulk Handling Awards, this year taking place at BULK2020. Nominations for the awards close on Friday 28 February, with finalists to be announced on 6 March 2020 and winners revealed at a gala dinner on Thursday 2 April. Getting innovative ideas off the ground can be difficult which is why Grant Wellwood, General Manager for Jenike and Johanson, shares his insights on the business world of bulk handling. He explains that there are a number of roadblocks that stop new technologies or solutions from being implemented, even if they would dramatically improve an operations. One of these challenges is the fact that employees rarely get into trouble for maintaining the status quo, but when it comes to champion something new, it could potentially lead to some serious consequences. You can read more of the story and learn how to navigate the complex process of championing change to big bulk handling companies on page 42. While it may not be flying cars, in this edition of ABHR we also speak to innovators in the industry, Neil and Christine Kinder. As founders of Kinder Australia, they discuss how innovation has helped their business grow from a small operation out of a Melbourne home to an international supplier. You can read more on page 28. This year is set to be massive for the bulk handling industry, with one of the country’s largest dedicated bulk handling expos, BULK2020, taking place on 1 to 3 April. We look forward to seeing you at the show.

William Arnott Editor - ABHR

6 І Australian Bulk Handling Review: January/February 2020


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NEWS

thyssenkrupp to deliver world’s largest rail mounted stackers and reclaimer for South Flank BHP HAS AWARDED THYSSENKRUPP Industrial Solutions (Australia) the contract to deliver some of the world’s largest rail-mounted, fully-automated stackers and reclaimer. The company was tasked with designing, supplying, building and commissioning two stackers that will deposit iron ore into stockyards for loading, along with a reclaimer for loading the ore into trains for BHP’s South Flank project in the Pilbara of Western Australia. The machines will each have a capacity of 20,000 tonnes per hour, which thyssenkrupp said will make them the largest rail-mounted stackers and reclaimer in the world. thyssenkrupp has designed the machines to be fully automated

and adhere to the latest statutory requirements for functional safety as defined in AS4024 and AS61508. A combination of GPS, SIL-rated encoders and limits have been used to provide machine collision avoidance, with the machines digitally connected and monitored from a remote, centralised control room. Each machine was locally designed and manufactured, with pre-assembly underway in Perth. Many of the largest pre-assembled modules are complete and will be transported from their current location at the AMC complex in Henderson, to the BHP South Flank site. Construction of the machines is expected to commence in January 2020, with a target of having the first machine commissioned and ready for

first ore by 2021. “It has been a great privilege to lead thyssenkrupp’s team through design, procurement, fabrication and preassembly phases so far, and achieve 50 per cent overall project progress milestone ahead of the plan,” thyssenkrupp Industrial Solutions (Australia)’s Project Director – South Flank Project Zoran Matijevic says. “I look forward to logistics, construction and commissioning phases and final handover of this equipment.” thyssenkrupp Industrial Solutions (Australia)’s Chief Executive Officer Johann Rinnhofer says the project has created several hundreds of Perth, Henderson, Kwinana Beach and Western Australian-based jobs since work started in September 2018.

WA Premier, Mark McGowan amongst the thyssenkrupp Industrial Solutions (Australia) construction team at the AMC.

Australian Bulk Handling Review: January/February 2020 І 9


NEWS

Port of Melbourne unveils 30-year plan A key part of the strategy is to improve landside transport connections.

THE PORT OF MELBOURNE has released its 30-year Port Development Strategy which outlines 10 key projects to improve capacity and respond to Victoria’s growing needs. Port of Melbourne CEO Brendan Bourke says the strategy is a roadmap for the future development of the port. “Our community increasingly relies on the Port to deliver the everyday goods needed to support our daily lives,” Bourke says. “We are committed to investing in the Port to ensure it remains the premier port in Australia, a cornerstone of the Victorian economy, and to move goods in and out of the port to their destination more quickly.” A key part of the strategy is

to improve landside transport connections for industry. “The Port’s plan for rail terminals supports the Government’s intention to move more freight on rail. We are working with the Government to progress this project,” Bourke says. “Moving containers by rail will help get trucks off local roads, particularly in the inner-west of Melbourne.” The Port Development Strategy aims to provide a flexible framework for the next 30 years to respond to industry trends and innovation. The document will be refreshed every five years as new information becomes available. It was developed through consultation with 190 stakeholders from industry and the community.

Global sugar market faces largest supply deficit in five years PRODUCTION CUTS IN INDIA, Thailand and the EU have helped create one the largest supply deficits for global sugar markets in five years – around 8.2 million tonnes – according to Rabobank’s latest global Sugar Quarterly report Currently, the supply deficit is three million tonnes more than anticipated three months ago, largely due to early-season dryness in India, and later, flooding, which is expected to drive a 21 per cent drop in Indian production. Thai production is expected to drop by a similar percentage, due to drought earlier in the year, while in the EU, planted area has been scaled back due to lower price signals.

The report says while “this more positive tone has arguably been longawaited”, the near-term abundance of stocks (particularly in India) – coupled with largely disappointing import demand – continues to weigh on prices and will limit further upside.

Australia For the Australian sugar industry, the report says the pace of harvest has now caught up with last season, after lagging throughout, with the harvest now essentially finished. However, sugar output, according to Rabobank’s commodity analyst Charles Clack, is forecast to fall to its lowest level since 2012/13 to around 4.2 million tonnes.

10 І Australian Bulk Handling Review: January/February 2020

“The dryness we have seen throughout the season, particularly the lack of in-crop rainfall, has significantly impacted yields,” he says. “This could have a bearing on next season if rains are not received in coming months.” Clack says despite the lower output, over three million metric tonnes of raw exports are still forecast in the current season, with Japan, South Korea and Indonesia remaining key markets for Australian sugar. “In terms of the price outlook, global fundamentals are expected to see prices trade in the vicinity of $440/ tonne in the first quarter of next year before rising to around $475/tonne by year end,” he says.


NEWS

Rema Tip Top wins contract to deliver 50km conveyor REMA TIP TOP HAS BEEN SELECTED to install more than 50 kilometres of conveyor belting for BHP’s South Flank Project. Monadelphous chose Rema Tip Top for the project in the Pilbara, Western Australia, due to the company’s previous track record and working relationship. Rema Tip Top will deliver splice kits and help with the installation and splicing of steel cord and fabric belt on five conveyor systems, three of which are overland conveyors. 77 rolls of belt are to be installed on the project with 77 splices to be completed in total. “This project represents a significant win for the business and is a testament to the commitment

Monadelphous chose Rema Tip Top due to the company’s previous track record.

we have shown to delivering quality projects,” Rema Tip Top Australia Projects Manager Steve Hipwell says. “Monadelphous has a substantial pipeline of works in the resources, energy and infrastructure sectors so it’s great to

continue to build on our successes with this leading engineering company.” “With mobilisation set to begin in Q2 2020, we look forward to the successful completion of this project and growing our capabilities with Monadelphous.”

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CBH makes largest annual infrastructure investment THE CBH GROUP HAS MADE ITS largest ever annual investment into its infrastructure network, with around $240 million spent to enhance the supply chain’s efficiency. Around one million tonnes of new permanent storage were added to the network in the 12 months to the end of September 2019. CBH has also installed throughput enhancement projects at 36 receival sites and set up 16 new weighbridges, with a goal of keeping network fees competitive, increasing throughput capacity and meet export demand at the right time to capture value for growers’ grain. CBH General Manager Project

Delivery Pieter Vermeulen says the works completed this year built on the accelerated pace of delivery of network projects in recent years. “Since 2018, we have added more than 1.7 million tonnes of permanent storage and delivered more than 45 throughput enhancement projects that enables CBH to receive grain faster, meaning reduced waiting times at site during harvest,” Vermeulen says. CBH General Manager Operations Ben Macnamara says the ongoing investment in the network would provide growers with an improved and more efficient network. “By adding storage to the network

and improving our capabilities in inloading grain we are steadily working towards meeting the increased pace at which growers are delivering at harvest time,” Macnamara says. The last of CBH Group’s permanent storage expansion projects for harvest have been completed, with the largest tripling the size of the McLevie receival site and adding 236,000 tonnes of new storage. Around one million tonnes of new permanent storage were added to CBH’s network.


NEWS

Belt splicing now a trade in WA THE WESTERN AUSTRALIAN Government has officially endorsed Fenner Dunlop’s Belt Splicing course as an Apprenticeship/Trade. The recognition means that the company can now offer employees a learning pathway with a national certification and trade papers through its Enterprise Registered Training Organisation (RTO). Fenner Dunlop General Manager of Safety, Training & Technical Vicki Wust, started the process with the Resources Industry Training Council (RTIC) in July 2018 to initiate the trade recognition for Fenner Dunlop’s Conveyor System Technicians in Western Australia. This led to collaboration between the industry and the State Training Board and WA Department of Training

and Workforce Development. “Fenner Dunlop are industry leaders, with a proven track record for developing and upskilling both new and experienced Belt Splicers through their nationallycertified career Fenner Dunlop can now offer employees pathway,” Vicki says. a learning pathway with a national “I have a vision certification and trade papers. to see Belt Splicing recognised as a trade across Australia. Currently two more than 1400 belt splicing states down and five to go.” qualifications across New South Wales, Fenner Dunlop’s 30 WA belt Northern Territory, Queensland, splicing trainees have all transitioned South Australia, Victoria and Western onto the new apprenticeship scheme. Australia, with more than 300 new The company’s RTO had delivered students.

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PRODUCT NEWS

Measuring the mass flow WHEN A LIME PLANT IN POLAND needed to measure the amount of material in freefall after an air slide, it encountered a conundrum. The company had been using impact plates to measure the amount of extracted lime, however, this led to problems occurring within the mechanical components. Caking began on the impact plates, dust was generated and mechanical wear were causing frequent shutdowns of the plant for maintenance work. The solution came in the form of the MaxxFlow HTC sensor, which

SWR Engineering has specifically designed to replace impact plates in this type of process. Primarily used to measure the volume of bulk materials after mechanical conveyor systems, the MaxxFlow HTC does not make contact with the materials and contains no moving parts, limiting the impact on the flow of solids and ware by abrasive materials. It can be used in a number of installation places, such as in pipes or ducts, and can even withstand harsh processes thanks to its ceramic

The MaxxFlow HTC sensor.

inner tube. In addition, it is pressure resistant up to 10 bar, can operate in temperatures up to 120 °C and is completely dustproof.

Concetti launches two-in-one bagging system ITALIAN AUTOMATIC BAGGING and palletising system manufacturer Concetti has launched a new packaging system for animal feed supplements called the IGF 1200 Gemini. The Gemini can manage medicated and non-medicated feeds within the same machine while minimising the risk of cross contamination between

The filler is equipped with two separate weighing and filling systems.

product batches. The filler is equipped with two separate weighing and filling systems, which The IGF 1200 Gemini work alternately to reduce the risk of transmitting active substances between products, needs of the manufacturer before being along with an efficient cleaning system. conveyed to the palletiser. Preformed bags, once full, can then Installation of the Gemini requires be sewn or heat sealed based on the less space when compared with two different packaging plants. An automatic bag holder with selectable openings means the system can manage a wide range of bag sizes, including pre-made open-mouth bags from 2.5 to 25 kilograms, flat or gusseted bags, or raffia bags. It can handle several types of granular or powdery products and can produce up to 800 25-kilogram bags per hour, or 1000 five-kilogram bags per hour. The machine can be configured with an additional four-column palletiser, suitable for partially-filled bags.

Australian Bulk Handling Review: January/February 2020 І 15


COVER STORY

The PTF Flour Bagger in action.

New year, new name for Kockum’s Bulk Systems It has been almost two years since Premier Tech acquired Kockums Bulk Systems (KBS). Francois Steyn, KBS Managing Director, speaks to ABHR about what the company has in store for 2020 and what its new name will be. IN 2018, NEWS BROKE THAT Australian pneumatic conveying and powder handling company Kockums Bulk Systems (KBS) had been acquired by Canadian company Premier Tech. The acquisition helped Premier Tech establish a beachhead in the Australian market, increasing its worldwide reach and reinforcing its local engineering and support capabilities. Now, almost two years since the acquisition, Francois Steyn, the Managing Director of KBS, says both companies have become much closer. “It’s like having a big brother. We’ve been able to expand our knowledge, training and tools,” he says. With additional international assistance, KBS began to expand its packaging business, develop its powder handling offering for export and aggressively grow its support business to cover all KBS and Premier Tech installations across Oceania. Packaging, which had previously been a much smaller part of KBS’ business,

suddenly became the main event, according to Steyn. “Since Premier Tech came on board, the increased product line vastly widened our scope of offering. We’ve been able to get into other industries where we haven’t been able to before.” One of the main benefits of Premier Tech’s offering is that KBS can vertically integrate into processes upstream of the packing line. Steyn says it is common to see companies focusing on integrating a new production line but don’t give much thought to the bagging system until later. “We regularly get invited into the processes discussion, which helps us get early notice of a project,” he says. An example of this can be seen when KBS began working with a large flour producer. KBS introduced the concept of dense phase pneumatic conveying to the flour company, showcasing the benefits compared with traditional methods of conveying. Dense phase pneumatic conveying moves powders through a pipeline with

16 І Australian Bulk Handling Review: January/February 2020

as little air as possible. This is because the air is the most expensive part of the process, and by increasing the pressure and dropping the volume, it creates an economical way of conveying. Steyn says KBS got involved with the project because of Premier Tech’s bagging machine for the flour industry, the Premier Tech Flour Bagger, also known as the PTF. “It’s an absolute game changer, this machine,” he says. “The PTF is a combination of proven technologies reconfigured to allow the machine to bag at high rates and still maintain accuracy. Two features that are not often seen together in our industry.” Customer support has been a priority across 2019, with KBS aiming to continue to ramp up the growth of its support team. KBS employs non-traditional methods when it comes to service, focusing on customer engagement and education to teach them the ins and outs of a machine. KBS’s service teams go out and help their customers understand how to get the most


Premier Tech aims to guide through the process of automation.

value out of the machine, teaching them some of the operational secrets and tricks. Steyn says that by doing this, KBS also learns a lot about how its customers interact with its products and uses these insights to improve designs. “When an operator works with a machine for months on end, they very quickly learn how to best use some of the features,” he says. “We make a big point of servicing our customers through the first year, from day one after we hand over the equipment. We offer a detailed program for the first year that we want to start as early as possible, so that our customers know they’re covered. “This reduced the amount of warranties we have by a big number. By training the customer’s operating and maintenance team, we ensure the machines are taken care off and this is the most important part of consistently achieving high throughput and longevity.”

still be on it, as a Premier Tech brand,” Steyn explains. The business has put in extensive work to ensure the transition to the new name will be as smooth as possible, updating its IT systems, branding and signage as well. Steyn says it’s important to get the move right, as the Kockums name remains strong and trusted within the industry. One event that will provide Kockums a platform to explain its new name to the industry is BULK2020. The company is a platinum sponsor of the event, which will bring the bulk handling industry together on 1 to 3 April, 2020, at the Melbourne Convention and Exhibition Centre. BULK2020 will play an important role in this transition for the company, according to Steyn, as it provides a platform for KBS to explain to the industry that the KBS team, which they have come to know and trust, is still alive and very

well, just under a different name. “It’s very encouraging to see how many people in the industry we have a strong relationship with,” he says. “New customers will also be able to engage with our technology and learn more about how we can help. It will be a place for our customers to visit and spin a yarn with our guys on the stand.” Premier Tech aims to make a difference through its people and technology. Automation is a key part of this goal, whether it is a first time automator or a corporation expanding existing facilities. The process of undertaking this change is often stressful and uncertain, which is why Premier Tech aims to help customers through the process. Steyn says it’s not only about the technology, but also about being a trusted partner from where the idea takes shape to where the change is implemented and delivered. He adds that delivering change is not linear and transactional, it’s complex and works well when there is a relationship based on trust. For the year ahead, KBS is looking to become comfortable operating under the new Premier Tech name, culture and values. “We’re excited for the change and want everyone to know we’re the same Kockums wearing a new Premier Tech jacket,” Steyn says. “In the future, we hope to see more of the KBS bulk handling projects integrated with Premier Tech packaging lines worldwide. There’s still a lot to do, but we’re all excited to keep growing.”

Changing names Kockums Bulk Systems will be changing its name to Premier Tech Systems and Automation over the next 12 months. The Kockums name will continue to live on as the brand for all our bulk handling solutions. This aligns with all of the other brands and businesses acquired by Premier Tech, which is undergoing a worldwide rebranding process. “Whenever we ship a piece of materials handling equipment, be it a vessel or a structure, the Kockums name will

Premier Tech acquired Kockums Bulk Systems in 2018.

Australian Bulk Handling Review: January/February 2020 І 17


PULLEY LAGGING

The common causes of ceramic lagging failure David Molesworth, Managing Director of pulley lagging specialist Elastotec, explains some of the most common reasons that ceramic pulley lagging fails. CERAMIC PULLEY LAGGING IS often used for pulleys that require a long, trouble-free life to avoid unplanned conveyor shutdowns. For mining companies, these shutdowns can cost thousands of dollars per minute. While ceramic lagging can be more expensive when compared with other options, its longevity helps make financial sense. A key contributor to the longer service life of ceramic lagging are the tiles bonded to the rubber backing. These are made from aluminium oxide, an extremely hard ceramic material that provides exceptional wear and abrasion resistance. It is critical to the performance of the lagging that these tiles remain in place during service. Because pulley lagging is used in demanding, dynamic applications where the tiles are loaded and unloaded every time the pulley rotates, constant flexing can quickly wear out areas of weakness in the adhesion between the tiles and rubber. This is one of the biggest causes of pulley lagging failure and can occur

Elastotec conducts extensive outdoor aging tests to check the ceramic tile adhesion and has seven years of test data with no tile debonding.

The rubber remains in contact across the entire tile surface, creating a 100 per cent rubber tear bond.

for two reasons: debonding of the tiles from the rubber backing and physical damage, which tears the tiles from the rubber backing.

Tile debonding Aluminium oxide tiles must be treated with chemical adhesion promoters or adhesives in order for them to attach to the rubber backing. There is a vast range of adhesives available from different manufacturers and most will provide a strong initial bond between the tile and rubber if applied correctly. This can be tested by holding the lagging in a fixed position and applying a load to the tile. A good bond has been achieved when the load applied to the tile is eventually able to tear it out of the backing with a layer of rubber still attached to the tile. If the rubber remains in contact across the entire tile surface, this is called a 100 per cent rubber tear bond. Adhesion of ceramic tiles relies on a chemical reaction between the tile, the adhesive and the rubber backing. Ceramic tile loss due to de-bonding occurs when these chemical reactions break down and stop working effectively. Break downs can be caused by poor lagging manufacturing practices, or lagging subjected to outdoor exposure, ultraviolet light, sub-zero temperatures, prolonged service above 50°C, and contact with acids, bases or oils.

18 І Australian Bulk Handling Review: January/February 2020

David Molesworth, Managing Director of pulley lagging specialist Elastotec, says it is critical that extensive adhesion testing is carried out under the full range of conditions that the ceramic lagging will be subjected to in service to ensure that the tile/rubber bonds remain effective. “Unfortunately, very few ceramic lagging manufacturers do this testing,” he says. To identify if tiles have de-bonded, Molesworth advises to inspect the recesses in the rubber backing where tiles are missing. If they are smooth and have a detailed imprint of the back of the tile, often seen as ribs or marks, it is likely the adhesion has failed. “Ceramic tile loss due to de-bonding is always a production fault and is the lagging manufacturer’s responsibility,” he says.

Physical damage This form of tile loss occurs when the load applied to the tiles in service exceeds the strength of the rubber backing layer, resulting in the tiles being torn out of the rubber backing. The tile is often removed with a layer of rubber bonded to the tile on all surfaces that were in contact with the rubber. Molesworth says this is often seen on non-drive pulleys and rarely on drive pulleys. “In particular, we see physical damage causing tile loss on high-tension non-


drive pulleys subject to high localised shear stresses, such as head pulleys with short transitions or bend pullets in contact with the dirty side of the belt and subject to carry-back,” he says. “On the latter types of pulleys, when the system is new the lagging performance can be okay, but as the centre of the belt wears, the localised shear stress in the centre of the belt increases dramatically and eventually will result in the tiles being

torn from the lagging. “The presence of carry-back on the uneven belt surface can accelerate this.” Elastotec has spent the past seven years studying the various causes of tile loss and failure and has developed a range of measures to eliminate tile de-bonding and tile loss due to physical damage. The company’s Hot Vulcanised Ceramic Lagging can handle the harsh environments often found in the mining industry, such as a non-drive pulley with continuous exposure to carry-back. Figure 1 shows that although the tiles have been cracked in this environment, none have de-bonded nor are missing. The pulley remained in service until a bearing failure necessitated a pulley change out. Eight years of outdoor ageing adhesion data, testing in temperatures from -40°C to 60°C, and data from more than 800 pulleys installed internationally, has allowed Elastotec to guarantee no tile loss due to de-bonding from its ceramic lagging.

Molesworth says consultation with conveyor maintenance personnel and evaluation of the operating requirements for each conveyor is required before the best lagging can be selected for each application. “Ceramic lagging is not the cure-all solution for all forms of lagging failure,” he says. “Failures that occur due to high localised shear forces, and/or the presence of carry back causing tiles loss due to physical damage, require a different type of lagging.”

Figure 1: Tiles cracked due to carryback but no tiles missing.


BULK2020

Sensing innovation John Leadbetter, Managing Director of VEGA Australia, tells ABHR what and why the company will be sponsoring and exhibiting at BULK2020.

The company’s 80 gigahertz range is able to include a narrower angle and a better dynamic range to read signals faster and with greater accuracy.

UNDERSTANDING HOW MUCH product is being stored, shipped or sold is often vital to ensuring operations are safe and profitable, especially when handling bulk materials. The technology used to handle this measurement has come a long way since the humble scale, becoming more advanced, accurate and automated. VEGA has been in the business of measurement for more than 60 years, operating across 80 companies. Its primary function in industry is to provide level measurement technology for use across a variety of sectors using a range of different technologies. John Leadbetter, VEGA Australia’s Managing Director, says the vast majority of its customers are looking to sell a product and accurate measurement systems gives better control over their inventory. “The more reliable their level measurement, the more understanding they have of what they’re looking to sell,” he says. To connect with potential customers and support the local bulk

handling industry, VEGA Australia will be sponsoring and exhibiting at the Australian Bulk Handling Expo (BULK2020), from 1 to 3 April, 2020 at the Melbourne Convention and Exhibition Centre. At the event, VEGA will display the latest advances in its 80 gigahertz radar technology, which has become a focus for the company. Staff from Germany will also be present at the event to learn more about the local market. Leadbetter says radar sensors have developed significantly since they were first introduced in the early 1990s. “Radar technology has been around for decades, but like any advancement in technology, the latest generations are 1000 per cent better than the originals,” he says. “Our first radar sensors to reliably measure solids were released in 2014 and the market has since accepted them as a reliable and accurate method of level control. VEGA’s radar sensors collect level measurement information by producing radio waves and detecting the echoes,

20 І Australian Bulk Handling Review: January/February 2020

which are converted into an electronic signal that can be displayed on site or in a process control system. Its 80 gigahertz range exceeds the previous 26 gigahertz series and is able to include a narrower angle and a better dynamic range to read signals faster and with greater accuracy. Leadbetter says that there is a lot of value in physical demonstrations, as people are more likely to trust a product after seeing it in use. “Demonstrations tend to be more believable – it’s rare that someone would buy a car from just a brochure, so why wouldn’t they also want to see other products get used before a major purchase?” he says. BULK2020 aims to bring the diverse world of bulk handling together under the one roof to showcase some of the latest technologies and innovations available in the market. It is aimed at bulk commodity producers that are interested in the latest equipment to help them manage their businesses with efficiency. Equipment such as conveyors, silos, motors and drives, belt scrapers, container tipplers, dust control systems, and weighing or level measuring products, among many more, will all be on display at the event. VEGA aims to take advantage of the diverse mixture of attendees at the event. It plans to showcase its strengths in the bulk handling sector for a number of applications. Leadbetter hopes people will come across the stand and discover products they didn’t know existed, or could solve their problems. “We’d like to meet all types of people at the show, from systems engineers, consulting engineers and installation contractors, but most importantly, the end users and people who own the plants to show them what the technology can do,” he says. “VEGA offers technology that will


innovations but adds that change is vital to survive in an evolving sector.

VEGA has been in the business of measurement for more than 60 years.

work for applications and that you can rely on. Our sensors have been designed for the bulk handling industry and can handle some tough environments, where other products might not be able to.” Leadbetter says that Australian businesses can be somewhat hesitant to take the plunge when it comes to new

“Certain practices of doing things are no longer acceptable, especially when it comes to safety,” Leadbetter says. “Health and safety legislation have made it even more important to embrace technology that keeps workers out of harms way.” VEGA’s sensors are all Industry 4.0 and Internet of Things compatible, using Bluetooth to wirelessly transmit level measurement data. This means that there is less of a need to have workers operating at heights as operators can check sensors from a distance. Its suite of sensors and digital platform are also backwards compatible, meaning the majority of VEGA’s instruments manufactured since 2002 can take advantage of this. The company takes customer support seriously, offering factorytrained service technicians and dedicated training facilities to ensure its

customers take advantage of hundreds of years of combined experience. Leadbetter says the team at VEGA are excited for the event and are looking forward to listening closely to the local market. “The best way to find improvements comes from feedback,” he says. “That’s one of the things we are looking for at BULK2020, to help us find advancements to keep supporting the Australian bulk handling industry.”

Fast Fact BULK2020 will take place at the Melbourne Convention and Exhibition Centre on 1 to 3 April, 2020. For more information and to exhibit, contact Luke Ronca at luke.ronca@primecreative.com.au or 0402 718 081. www.bulkhandlingexpo.com.au/


BULK2020

BULK2020 leaps forward Engineering software solutions provider LEAP Australia will sponsor the BULK2020 industry conference. ABHR speaks to Peter Rizkalla to find out what it will be exhibiting at the show. Rocky DEM simulates the movement of granular material.

COMPUTER PROGRAMS AND software have evolved to play an increasing part in an engineer’s toolbox. Without them, innovations such as automated vehicles, digital twins or internet of things-capable sensors would not be possible. Simulation software is one such tool that helps designers and engineers understand how their systems work and will be on display at the 2020 Australian Bulk Handling Expo (BULK2020) thanks to LEAP Australia, local partner of ANSYS and Rocky DEM. The event will take place from 1 to 3 April at the Melbourne Convention and Exhibition Centre and bring the bulk handling industry together to showcase the latest equipment and technology. The conference will discuss key issues facing the bulk handling industry while the expo will have equipment such as conveyors, silos,

motors and devices, belt scrapers, and dust control systems on display. Peter Rizkalla, Product Manager at LEAP Australia, says the company will have the world’s leading Discrete Element Method (DEM) simulation software, Rocky, on display at its booth. The software simulates the movement of granular material and the way it interacts with a bulk handling system. It allows engineers to visualise the general flow trajectory to understand forces, velocities and how they affect critical points in a system. This can help to find where spillage, breakage or wear may be an issue and allows for changes to be made early in the design phase. “Our main objective at the show is to educate Australian engineers on how DEM simulation applies to their work and the many benefits of using Rocky for DEM,” Rizkalla says. “The uptake of Rocky over the

past six to seven years has been overwhelming. We’ve had lots of interest throughout Western Australia and Queensland in the mining industry and Rocky DEM has proved very popular with bulk materials handling product designers and engineers.” “BULK2020 will be a good opportunity to engage with the bulk material handling market not only in the mining space, but in the pharmaceutical sector, food and beverage manufacturers or agriculture.” The event aims to connect the diverse world of bulk handling to help facilitate knowledge sharing across industries. The Australian Society for Bulk Solids Handling (ASBSH) will hold an industry conference during the event to discuss the latest advances across multiple technical streams. While each sector often has industry specific equipment, wear, blockages or

BULK2020 will be a good opportunity to engage with the entire bulk material handling market.

22 І Australian Bulk Handling Review: January/February 2020


overloading on equipment and breakage are issues that can cause unnecessary downtime in any bulk handling situation. Rizkalla says productivity requirements have increased, with operators pushing their equipment harder to get more throughput. “When you do start to push systems to the limit, you encounter issues. That’s where simulation is beneficial. You can find out what the implications will be when changes are made to a system, or when a system is operating at the threshold of its intended operating conditions.” Networking opportunities at the event were a major draw for LEAP Australia. The company will take part in both the exhibition and the technical conference to connect with current and future customers. Its booth will be staffed with DEM simulation experts to answer questions regarding the virtual

prototyping process and the ability to run simulations on a desktop. It will also be a chance for the company to demonstrate its software capabilities through other tools like ANSYS for structural and fluid flow applications. BULK2020 Show Director, Simon Coburn, says he is thrilled that LEAP has decided to support the event as a sponsor. “We’re committed to providing conference attendees with the best spread of content to ensure they have the information they need to enhance their bulk solid handling operations,” Coburn says. “LEAP Australia’s support of the event means that we can offer delegates a wealth of up-to-date knowledge when it comes to software applications that could assist their business.” BULK2020 will also host the 2020 Australian Bulk Handling Awards, which acknowledge the outstanding achievements of the businesses and

people within the industry. Nominations for the awards are currently open and close on 28 February. The event will be held in conjunction with MEGATRANS2020, one of Australia’s biggest transport, logistics and supply chain events. One ticket will provide access to both exhibitions. Rizkalla is looking forward to the event and says he is excited to show off Rocky. “Development has come a long way with many updates coming as a direct results of customer feedback, and we will continue to respond to the requirements of our customers and the problems they are trying to solve,” he says. “Lots of companies are facing bulk materials handling issues and we want to help them troubleshoot and optimise their systems and operations. From our perspective, virtual prototyping is one of the most cost-effective ways to do that.”

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PUMPS

Pumping up gold production rates at Greenfields Mill By implementing two new Metso HH200 pumps, the Greenfields Mill has been able to almost halve operational costs through simplified labour and equipment. THE GREENFIELDS MILL, LOCATED in Western Australia’s goldfields three kilometres east of Coolgardie, has supported the local gold mining industry for more than 20 years. It provides crucial toll milling services to local miners with a unique setup of three ball mills. The circuit can be optimised for gold recovery depending on the needs of different clients and in its current configuration, the plant can process up to one million tonnes each

year. Investment organisation FMR Investments operates the mill. Stockpile ore is delivered to the site before passing through a three-stage crushing circuit consisting of a primary jaw crusher then through secondary and tertiary cone crushers. A double deck screen grades feed from the secondary and tertiary crushers that remove undersized material from the circuit. The crushing system produces a P80 product size – 80 per cent passing

size of the circuit product – between six and eight millimetres, which is then transferred and stored in a 1000-tonne mill feed bin. The mill circuit consists of 1300-, 875- and 500-kilowatt ball mills, with classification of leach feed product handled by 15-inch cyclones. Free gold particles in the cyclone underflow are separated in a concentrator and sent to the gold room for direct smelting, while the remaining underflow goes back to the grinding circuit to be further reduced. Overflow product is sent to a carbonin-leach circuit, where gold is dissolved from the ore in a cyanide solution in the presence of oxygen. The gold cyanide complex molecule is then absorbed into activated carbon and stripped in a process known as elution. Gold is later recovered from the pregnant strip solution by electrowinning onto steel wool and direct smelting before it is shipped to an external refinery.

Mill discharge pumps a critical component of the plant

Regular inspections and maintenance helps FMR to ensure mill discharge pumps are ready for action.

24 І Australian Bulk Handling Review: January/February 2020

Critical to the operation of the mill-toclassification process are the plant’s mill discharge pumps. The pumps transport the milled


Greenfields Mill has the capacity to process one million tonnes of ore per annum.

slurry up a large vertical pipe to the classification cyclones, processing high volumes of highly-abrasive materials. This means key wear components need to be monitored regularly to ensure the pumps can continue operating efficiently and to prevent any unexpected downtime. Alternative Registered Manager at Greenfields Mill, Morgan Dombroski, says that the mill discharge pumps are a critical part of the site’s process.

“The pumps feed the classification cyclones, which are the mother of the whole plant. If the pumps are down, we aren’t producing a product - which is a big deal for our site,” she says. Dave Scott, FMR’s Maintenance Supervisor, says the pump setup has been designed to ensure there is always one pump available. “If the mill circuit is stopped, it basically costs the business about

$40,000 per hour,” Scott says. “That’s why we have a pair of pumps for this application. If the active ‘duty’ pump fails or is under maintenance, there is always a standby ready to take over.”

Innovative pump design slashes maintenance costs In 2014, FMR purchased two Metso HH200 pumps to replace existing units nearing the end of their effective life.

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PUMPS

To maintain the previous pumps, the operators had to disconnect the suction and discharge spools, front casings and case liners to access critical internal components, which required a mobile franna crane. Because of the labourintensive nature of the job, it can take up to eight hours to fully complete, making it difficult to maintain the pumps regularly. The new mill discharge pumps are equipped with Metso’s unique slidebase technology. The slide-bases allow operators to open the pump without moving the suction and discharge pipework, making it easier to inspect wear components and conduct routine maintenance. The slide-base also has reduced the time required to get a blocked pump online again. Morgan Dombroski, Alternative Registered Manager at Greenfields Mill, says the site’s mill discharge pumps are now checked on a weekly basis. “Our team here have a lot of experience at this site and are good at forecasting maintenance activities,” she says. “We monitor the pumps through weekly inspections including a ‘shimming’ process. This optimises both front and rear impeller clearances which makes the pumps operate more efficiently and extends wear life.” Travis Dingle, FMR’s Maintenance Fitter, explains how shimming extends a mill discharge pump’s wear life. “The pump operates more efficiently when the impeller is closer to the volute liner,” he says. “If you have a wider gap between these components, larger particles get in and wear the volute down at a faster rate. Shimming ensures the gap is reduced and the pump operates effectively.” Dingle adds that the slide-base technology helps the team undertake this process quickly and with improved safety. “What makes it easy with the Metso pumps, is the hydraulic slide. We simply remove the volute bolts and pull the housing back to access everything we need – without the use of a crane,” he says. By conducting weekly inspections and shimming both mill discharge pumps, the Greenfields Mill has been able to reduce the frequency of major overhauls. Scott says this has reduced operational

costs for the site by about half while also creating a safer work environment. “The total cost of a full rebuild can be significant. There was a time when we had to do this monthly, but now, with regular maintenance, we get a lot more life from our impellers and housings,” he says. As the slide-base allows the team to conduct maintenance without a crane, there is no rigging gear that could potentially strike someone. Because the team doesn’t have to disassemble everything, most of the pinch points have also been removed. Roger Doyle, Pump Specialist at Metso, says FMR’s pump arrangement and preventative maintenance program are an industry best practice. “Having two pumps in place ensures plant availability by providing a backup option that can be implemented without any impact to production,” he says. “On top of this, the site takes full advantage of the slide-base technology and takes a very proactive approach to maintenance. This has benefits in terms of pump efficiency, but also means unscheduled servicing is much quicker and easier, as fasteners are exercised and anti-seized frequently.”

Unblocking production when the going gets tough Sediment or large foreign objects from the ball mill can cause the pump to become bogged, which can dramatically

26 І Australian Bulk Handling Review: January/February 2020

affect productivity. Bogged pumps most often occur if wear in the mill trommel allows a large rock or steel mill ball to pass into the pump or if there is an unexpected electrical mains failure on site. If this occurs, the pump must be dismantled to remove the blockage, which can be a time-consuming process. Dingle says this can be a significant job that must be carried out at short notice. “With most common pumps you have to take several components off, such as the front spool and cover,” he says. “This requires a franna crane and a person available with a ticket to operate it. This can be a horrible job that can take over four hours to finish.” Metso’s slide-base technology helps to speed up the job significantly, making the process simple. No key components need to be removed and no cranes are required. The team at FMR are able to unblock the mill discharge pumps in around 45 minutes, which can slash unplanned downtime. Dombroski adds that pump blockages can occur at any time, so there is peace of mind knowing the job can now be carried out quickly. “I’ve had a pump get bogged in the middle of the night and our operators need to drop everything and get it back online,” she says.

Roger Doyle and Dave Scott discuss pump maintenance.


“The slide-base design makes the job 100 per cent easier. If you bog the pump you can have it unblocked again within the hour.”

Local support Greenfield Mill has a lean workforce on site and relies on original equipment manufacturers to help support the equipment in operation. Metso’s local team are ready to assist with the day-to-day operation of the site and are able to provide any spare parts necessary at short notice. For Dombroski, it is also important to have access to people who have experience with her company’s plant and equipment. “We have spent many days together with the Metso team working on rebuilds and other activities such as the installation of new products,” she says. “Over this time, we have established a good rapport and they have proven to be easy to deal with in any situation. It is definitely good to have a local Metso

Ball mill, pumps, tec-taylor valve and pipe arrangement.

presence in Kalgoorlie to check in on us from time-to-time and make sure all is well. “They know the importance to

the plant of the equipment we have purchased, and they make sure the right parts are available to avoid any downtime.”

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INTERVIEW

Building blocks for a global foundation ABHR sits down with Neil and Christine Kinder to learn how they turned their family business from a small operation to an international supplier. Kinder Australia began with Christine and Neil operating out of their Melbourne home.

THE LEGO BRICK, FIRST released in 1958, has been named Toy of the Century twice, inspired five movies and continues to be loved by children around the world. In 1960, Godtfred Kirk Christiansen, Managing Director of the Lego group said: “We know our idea is a good one. We want only the best ... we must make better bricks from even better material

on even better machinery.” This mindset for quality is one that Christine Kinder, Marketing Manager at Kinder Australia, seeks to emulate. “When you look at [Lego] bricks, it’s hard not to imagine them lasting for hundreds of years, still with their bright primary colours and just as desirable as they are today to the children of the future,” she says.

28 І Australian Bulk Handling Review: January/February 2020

“In the bulk handling industry, we want to be the Lego, not the two-dollar shop toys that don’t last.” Neil Kinder, Managing Director of Kinder Australia, agrees. “You’re better off investing your money into something that lasts and will provide productivity and value. People have started to realise that if they buy something cheap, but it


doesn’t stack up, it’ll hurt them in the long term,” he adds. The family engineering business started with just Christine and Neil operating out of their Melbourne home. As the mobile phone network expanded, so too did the business, branching out to the rest of Victoria and eventually to cover all of Australia. Now, in the age of the internet, the business has gone global. Kinder Australia now services the South-East Asian market with a new, multilanguage website. Neil says the global trade environment has changed rapidly since the internet was introduced, bringing markets closer together. “You can buy something today from the other side of the world and have it arrive in the next week,” he says. “People aren’t too concerned about where something comes from now. Instead, they’re more interested in who they’re buying from. “Are they a trustworthy organisation? Will their products be reliable? What sort of global name have they got? These are the important questions.” Kinder has spent the past 30 years developing its reputation, aiming to provide a comprehensive range of high-performing, long-lasting, reliable equipment. Christine and Neil have made it their mission to surround themselves with the right engineers that have the ability to provide the expertise the company’s customers desire. Reinvesting into the business is a core part of Kinder’s strategy. When the company wins a big contract, it spends that money on improving itself for stable growth. Neil says it’s important to be conservative when it comes to taking risks in business. “We’re conservative with the way we operate, and we don’t try to take on jobs that are bigger than we are capable of doing,” he says. “We don’t want to operate a business where if we have one little problem, the whole thing implodes. “If you haven’t got a vision to survive, and that’s got to be deep in your soul, then you can have all the

plans in the world but it’s not going to work.” Innovation and development are vital to this survival. Christine says if you don’t keep up with the current industry movements and don’t keep moving forward, businesses end up moving backwards. The company’s goal is to find new ways of improving upon the technology that is already on the market. One example of this is the K-Dynamic Impact Idler. A finalist for the Innovative Technology award at the 2019 Australian Bulk Handling Awards, the dynamic impact idler is suspended above anti-vibration spring element mounts to provide cushioning and absorb the impacts of conveyed materials.

“We’re trying to educate that there are such enormous differences in products at the moment that customers need to do their research.” This helps to reduce unplanned maintenance and extend the life of the belt, rollers and frames in heavy-duty applications such as the hard rock and iron ore industries. When it comes to developing new products, Neil explains a number of drivers in the industry have helped focus their engineering. At the moment, the big issue Kinder is working to help solve is dust. Silica dust is known to cause a range of potentially deadly lung diseases, such as silicosis, and presents a health hazard to those working nearby. It is also an environmental risk, especially in cities which have begun encroaching on industrial zones. “Noise and dust can be a nuisance– nobody wants to live near that, and nobody really wants to work in those kinds of environments,” Neil says. “That’s why we developed our conveyor covers. Covers aren’t a new thing, they’ve been around for a long time, but in Australia, no one that we know of can deliver a conveyor cover straight from stock like we can.”

Industry engagement helps Kinder develop an awareness of the challenges that its customers are facing. Alongside its staff in the field, the company also makes a point of listening to customers and providing training workshops at its Melbourne facility. More than 45 people from around Australia have visited the workshops to learn how to get the most from Kinder’s products. The company wants to avoid “just another sales session” and instead makes them as educational as possible. “We want our customers to walk away from the workshops knowing that if there’s a problem, all they need to do is reach out and contact us for help,” Christine says. “We are the company with the knowledge. Whether or not we have the product, it’s the engineering we can provide.” Kinder Australia has plans to continue this education in 2020 and will focus on reinforcing customer research over multiple platforms. “Just because it’s red, doesn’t mean it’s the real thing,” Christine says. “We’re trying to educate that there are such enormous differences in products at the moment that customers need to do their research.” This customer outreach is set to continue at the 2020 Australian Bulk Handling Expo, BULK2020, in April where Kinder will be exhibiting. “The show is a fantastic opportunity for us, especially because it’s right on our doorstep,” Neil says. “It will give us a huge advantage, because people will be able to come and see what’s on offer and put a face to a name. That relationship building is incredibly valuable – you can’t put a dollar value on it.” Word of mouth has helped it grow, but Kinder’s future is on a digital horizon. Where mobile phones were what helped the company first grow, now it’s emails and websites. “It’s a busy time, just when we get a handle on one thing, something new will pop up,” Christine says. “But it’s been good fun, and it’s great to see our staff enjoying what they do. They’re our energy in the house and it reflects in the way they operate.”

Australian Bulk Handling Review: January/February 2020 І 29


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Supporting supplier success SEW Eurodrive tells ABHR why the company has decided to sponsor the Supplier of the Year award at the 2020 Australian Bulk Handling Awards. IN APRIL 2020, INDUSTRIES WILL be brought together to network, collaborate and share knowledge at BULK2020 and MEGATRANS2020. The two expos will bring the diverse bulk handling, freight and logistics sectors together, with one ticket allowing entry into both shows, and offers an excellent opportunity for networking and growth. As part of the event, the 2020 Australian Bulk Handling Awards and the logistics industry’s Mercury Awards will be held in tandem, shining an even brighter spotlight on exceptional individuals and businesses. Sponsored by SEW Eurodrive, the awards night will take place over a gala dinner on Thursday 2 April 2020 and aims to shine a spotlight on suppliers that have lifted their performance for the benefit of their clients. Guido Wagner, SEW Eurodrive Industrial Gears Manager, says the awards is an opportunity for the company to demonstrate its commitment to recognising and supporting industry excellence and innovation. “SEW Eurodrive recognises the importance of innovation, as our successes have been underpinned by innovative manufacturing, assembly and product solution set,” Wagner says. “The awards are an excellent SEW Eurodrive is a global designer of mechanical drive systems.

SEW Eurodrive has supported the awards for many years.

occasion for participants involved in the Australian bulk handling sector not only to get a deeper insight into the industry but also to celebrate its successes with a broad audience.” SEW Eurodrive is a global designer and developer of mechanical power transmission systems and motor control electronics, headquartered in Germany. It provides its customers with a range of solutions including geared motors and gear units, high torque industrial gear units, high-efficiency motors, electronic frequency inverters and servo drive systems, decentralised drive systems, and after-sales technical support or training. Businesses can sponsor awards and will have the privilege of presenting them to the winner. SEW Eurodrive is the proud sponsor of the Supplier of the

Year award, which recognises suppliers operating in Australia that have helped customers reach their goals. To be considered for the award, suppliers must have demonstrated the scope of their services in terms of locations, services offered and areas of expertise. They must also be able to showcase how they have excelled in productivity, efficiency, sustainability, safety and cost savings. Michael Klose, SEW Eurodrive Business Development Manager, says suppliers play a vital role within the industry. “A lot of the time, the focus is on the end user or the customer, but without a good supplier they wouldn’t be able to reach those goals,” he says. “By supporting the event, not only do we help showcase the suppliers and manufacturers that win, we also provide a positive space to acknowledge and encourage innovation. People that work hard deserve the recognition, and by providing that, it inspires others.” SEW Eurodrive has been a long-term supporter of the event, having sponsored it for many years. Klose says the publicity of the twin events will be beneficial to the bulk handling industry. “The competition will help the industry continue competing and growing,” he says. “I’m excited to see all of the finalists and to congratulate the winners.”

Australian Bulk Handling Review: January/February 2020 І 31


ACTUATORS

Moving grain stockpiling forward Kilic Engineering has used LINAK’s linear actuators to create a more efficient grain stockpiling technology. WHEN AGRICULTURAL SERVICES company Cargill began to review its supply chain infrastructure, it needed to find a way to optimise its stockpiling operations. The company had been using stacker conveyors for grain stockpiling which could move along a bunker as it filled up. However, a restrictive discharge chute movement at the top of the stacker was limiting the grain flow direction. Cargill reached out to mechanical handling equipment designer Kilic Engineering to design a solution that would improve the discharge chute and allow it to be independently moved up, down and sideways to fill a bunker more efficiently. Jason Kilic, Managing Director of Kilic Engineering, says that using electric actuators was vital for the upgrade. “We needed a product that was versatile, compact and simple to control. Something that would allow the discharge chute multidirectional movement without restriction,” he says. The solution came in the form of the LINAK LA36 actuator, an electric device that converts rotational motion in low voltage direct current motors into a linear push/pull movement. LINAK (short for Lineær Aktuator) manufactures actuators designed for applications where tilting, lifting, pulling or pushing with thrusts of up to 15,000 newtons is required. Its LA36 model has been designed for harsh outdoor applications. “LINAK’s actuators were the perfect fit,” Kilic says. “We’ve used LINAK’s technology before, across a range of applications, and have found them to be effective at what they do.”

The new chutes have helped to optimise Cargill’s operations.

The actuator is one of three parts that give the discharge chute an enhanced range of motion. A prototype of the design was rolled out at one of Cargill’s Victorian sites, which helped gather feedback for further adjustments. Lee Aris, LINAK’s National Sales Manager, says the company’s ethos is to work closely with original equipment manufacturers to ensure

32 І Australian Bulk Handling Review: January/February 2020

they can take ownership of the finished application and satisfy their customers’ needs. The two companies worked together closely, with LINAK providing advice on the model numbers and ratings for the required force and range. Reliability was a key component for the design, as the new discharge chutes would need to be retrofitted across 29 of Cargill’s stacker conveyors


around Australia. Kilic says the simplicity of the actuator’s design and assembly helped the engineering team ensure the machines would be consistent and uniform for each installation. “The LA36 is compact, low voltage and programmable, meaning we can connect a laptop to the actuator, upload a program and it will behave the exact same way, every time.” LINAK offers a free, downloadable software to configure the parameters of each actuator, using easily accessible prompters. This helps the actuators work in synchronisation with an application and can allow changes to be made to the stroke length, speed and current cut-off. In general, a lower voltage means there is much less chance of harming a user and the LA36 has been tested and certified for electrical operation in dust explosive atmospheres. With the expanded mobility and the ability to throw gain further, Cargill

The LA36 is compact, low voltage, programmable and designed for outdoor applications.

can now fill certain voids within the stockpile with less movement of the stacker itself, optimising the process significantly. LINAK aims to manufacture actuators that are maintenance free and long lasting, with some operating in the field more than 20 years.

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Kilic says there have been no issues with the actuators but knows that LINAK is close by if they ever need assistance in the future. “The simplicity of the actuators is their greatest strength. They’re smart, easy to use and require almost no maintenance,” he says.


SILOS

Blowing away the competition Local engineering is helping Optimum Grain Silos and Augers build structures able to withstand a one-in-200-year storm event. DOROTHEA MACKELLAR’S 1904 poem My Country describes Australia as a land “of droughts and flooding rains”. In this environment, and with extreme weather events becoming more common around the world and in Australia, the ability to withstand wild weather is becoming more important. This is why agridealer Optimum Grain provides its customers with the Cyclone silo. Manufactured from galvanised high-strength structural-grade steels, durability is at the forefront of their design. Designed to safely store cereal grains such as wheat, oats or barley, the silos are able to withstand a one in 200-year storm event. Joel Murphy, Director of Optimum Grain Silos and Augers, says this assurance is important for grain handlers and farmers that are investing

into equipment that should last more than 30 years. “Cyclone silos have a good reputation in the industry for being well designed and able to thrive in some of the worst of Australia’s conditions,” he says. He adds that stringent Australian engineering and manufacturing helps provide peace of mind for customers looking to protect their long-term investments. “Manufacturing in Australia means that anything we make has to live up to strict quality standards,” he says. “Because of this, when you buy Australian-made, you know you’re going to get quality.” Optimum is a family-owned business, operating out of regional New South Wales. Originally founded in 1996, the company prides itself on its extensive experience in providing solutions

for the grain industry. Optimum constructs the foundations of the silos, which incorporate a 100-millimetre step inside the silo to prevent moisture entering grain. It is also able to include a spiral staircase designed to meet Australian standards and in-floor aeration, designed to meet the needs of the grower. Cyclone silos use large wall sheets with fewer joins and bolts than other silos and have a wide corrugation profile, which reduces the risk of internal obstructions and hang-ups that can harbour insects. They comply with all relevant Australian Standards and are designed to be sealed to assist with fumigation processes. Murphy says the products have proven popular with farmers looking to improve their storage for future harvests. This was the case for Roly Dye, who installed two 1720-tonne grain silos for

Cyclone silos can withstand a one-in-200-year storm event.

34 І Australian Bulk Handling Review: January/February 2020


on-farm storage. The silos, measuring 14.5 metres in diameter, 11 metres in height and with a 30-degree angled roof, are on the larger side for on-farm storage, but help provide a system that can store the grain he planned to store. Aeration was an important factor for Dye, as the biggest drawback to storing his grain was hygiene and insect control. The aeration included in the silos means the grain can be kept at a temperature where weevils couldn’t breed and helped to prevent moisture migration. “I wanted to go with something that was more substantial that would last for a long time,” Dye says. Optimum also manufacturers a range of heavy-duty unloading augers which incorporate heavy-duty sweep augers, designed and manufactured in Young, NSW. Available with a full electrical drive, power take-off/hydraulic drive or a full hydraulic drive, the augers are made from structural pipe with a wall thickness of 4.8 millimetres and 6.4 millimetres.

Many of the steel components are laser cut to ensure a precise fit when assembled, following the company’s in-house design which uses tabs and slots so that components fit in the correct position reliably. They use a specialised walking advance system. This means the sweeps will advance into the grain without needing any assistance. Murphy says this offers safety benefits, as it is not necessary to enter the silo while the unloading auger or sweep are operating. “In fact, we place a sign on the silo door that says the silo must not be entered whilst the unloading auger and sweep are operating,” he says. Most of the drive arrangements are shaft mounted with a torque arm arrangement, helping to eliminate coupling and shaft alignment issues. The hydraulic drives are supplied by hoses routed through a rectangular hollow section steel duct, enabling the hoses to be replaced should a problem occur. All intake and outlet areas also

Heavy-duty augers are designed and manufactured in Young, NSW.

come with heavy sectional flight, fitted for long-term reliability. “Our team prides itself on only working with the highest quality products that meet rigorous Australian Standards,” Murphy says. “That’s why we work with Australian-made Cyclone Silos, made just down the road in Jindera, NSW.”

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SILOS

HE Silos believes that every grain counts.

Working smarter and harder Technological development and a tight-knit team has helped HE Silos reach its 50th year of doing business. ABHR speaks to third-generation family member Stevie Leigh Morrison about how it plans to grow. WHEN FLYING TO THE MOON, THE computer that guided Apollo 11, the Apollo Guidance Computer, had just 32,768 bits of RAM memory. Today, an average smartphone has around seven million times more memory. Computers aren’t the only technology that has made a giant leap during the past 50 years. Vehicles are safer, cleaner and verging on being autonomous, while similar improvements have been made in the bulk handling sector.

Advances in engineering in particular have allowed HE Silos to build bigger and better silos than ever before. The company, originally known as Hillston Engineering, began operating in 1969 in New South Wales and has been growing ever since. Stevie Leigh Morrison, a thirdgeneration member of the family business, says farmers and other silo customers now have a deeper understanding about how to best preserve grain and other

The company began operations in 1969 and has been growing ever since.

36 І Australian Bulk Handling Review: January/February 2020

bulk materials to get a better return on investment. “Back in the day you could just stick a silo on a farm and hope for the best. They’d use them to store grain from the harvest to sell later when the prices became a bit higher,” she says. “Short-term storage isn’t really a thing anymore, as longer-term storage and maintaining the proteins, moisture and quality of the grain have become more important.” The company strives to provide high-quality silos of all shapes and sizes, whether it’s a 1000-tonne flat bottom silo or a four-tonne silo with a cone base. Morrison says the success of the business, even through periods of crippling drought, can be attributed to the family’s tight bond. “We always have each other’s back and work closely together. We believe in what we are doing and have since the get go. But more importantly, we’re passionate about what we produce,” she says. “Most family businesses don’t make it, so for us to be still going strong is a testament to our dedication. I work with my mum and dad, and my grandpa can still be found in the workshop occasionally.”


At the start of its journey, HE Silos’ founders, Ivan and Patricia Morrison, would build whatever their customers needed, from silos to sheds or anything in between. The pair retired in January 2006 and have passed on the business to their children. The company makes use of two NSWbased factories, one in Forbes and one in Gunnedah, and employs around 70 staff across both. The majority of machinery within the factories were built by HE Silos itself, which the Morrisons say gives them a fundamental understanding of the manufacturing process. In addition, the factories make use of best-practice technologies and engineering processes to ensure maximum efficiency and safety. Safety has also become a much larger priority for HE Silos’ customers. As a result, the company has put more emphasis on developing equipment that reduces the chance of falls while working at heights and manual handling. All of its silos can be retrofit with

ladders, cages and platforms, so that users can ascend to the top of the silo safely. A remote lid opening kit allows the silo to open without needing to climb it as well. One innovation the team at HE Silos is particularly proud of is its Thermal Insect Control System, which allows farmers to fumigate a grain silo without needing to climb ladders. “We were up against big multinational companies, so it was a wonderful surprise when we took out that award,” Morrison says. “By developing this control system, we’ve eliminated all of the unsafe operations that are involved with fumigating a silo, such as the handling of chemicals at an unsafe height or climbing the silo multiple times.” Morrison adds that a big factor into the push for additional safety is the fact that many farmers now have additional workers on their site and want to ensure their property is a safe workplace environment – for themselves and their employees.

The team at HE Silos strongly believes in the expression ‘work smarter, not harder’. To do this, it makes use of a full-time research and development team which have been engineering a number of new technologies set to launch in 2020. Products are tested on a dedicated site in regional NSW to try and find the best way to improve them before they roll out to market. A focus on innovation is part of HE Silos’ guiding philosophy, “because every grain counts”. Morrison says each grain the company keeps at a high quality for later consumption is a grain that can go towards establishing food security. “The climate is changing and we’re seeing more intense droughts, floods and fires than ever before,” she says. “For us to stay in the 21st Century, we have to be on top of our game and move with the times. The time is now to act to ensure that my future grandkids can still be part of this company and have food in their belly.”

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VIBRATORS

Good vibrations ABHR speaks to Mark Thompson, General Manager of Oli Vibrators, to find out what separates a good vibrator from a bad one. AUSTRALIA’S BUILDING BOOM has led to an almost insatiable need for concrete, asphalt and other building materials. Process productivity is critical for the manufacturers feeding this demand, but when machinery breaks, this is jeopardised. One key piece of equipment for bulk material commodity producers are vibrators, especially when it comes to construction. Vibrators are used to consolidate and eliminate voids in concrete, especially when reinforcing around steel. In addition, being used for more complex shapes, vibration becomes vital. Mark Thompson, General Manager of Oli Vibrators, says that poorly designed and manufactured industrial vibrators run the risk of having inferior lifespans that end up costing more in the long term. “When you look at some of the products on the market, the quality just isn’t there,” he says. “As inferior vibrators start to wear, consistency of performance will drop, which has a flow-on effect to the rest of the operation. Imagine you are producing 10,000 bags of material a day, and then you find that you can’t get

your product into the bags properly. “You might need to pull two to three people off the line to deal with this, not only affecting productivity, but also creating an inefficient use of labour.” Safety can also become a concern, as manually assisting flow by striking a hopper can create a hazardous work environment and present ergonomic risks as well as damage to the asset. In addition, if a breakdown does occur, the impact of these inefficiencies begins to affect overall profits, meaning a replacement should be sourced as soon as possible. Thompson says Oli Vibrators prides itself on high-quality, European-built equipment and its large stock holding. “Product performance and reliability – whether out on site or in the factory – is of paramount importance,” he says. “There’s a limited timeframe to work in, and our customers need to know that the equipment will be

38 І Australian Bulk Handling Review: January/February 2020

The company ensures its warehouses are well stocked.

working as it should, when they need it. If a business has a hang up and isn’t able to get its product out of a silo or hopper, we can be there straight away.” When it comes to clientele, Oli Vibrators has found itself popular in the concrete sector. It has been involved with a number of major tunnelling projects in Melbourne and Sydney, along with highway infrastructure upgrades and pre-cast concrete manufacturing. Although its products are most often used in the construction industry, Oli Vibrators’ products can be found in recycling plants, in confectionary factories, or at the bottom of a coal mine. Thompson says the company takes a solutions-based approach, meaning it The business has a service centre in Scoresby, Melbourne.


can match the vibrators or flow aids to specific problems. “We can offer a specific fix for a process’ hang-ups, whether that’s ratholing or bridging or something else entirely,” he says. “Our range of equipment means we can provide the best tool for the job, instead of something generic.” The company is based in Modena, Italy, where it engineers and develops its products. Its mission statement, ‘when you need it, where you need it’ has helped form its strategy to keep all 18 of its global trading subsidiaries wellstocked. In Australia, the business has a service centre in Scoresby, Melbourne, along with a network of support agents across the country. Thompson says there will be a number of new products set to launch in 2020 that have been designed by expert engineers. “The vibrator market is competitive, so we rely on our high-quality products,

technical expertise and the ability to provide all the specifications an engineer could possibly want,” he says.

“We’ve got all that along with a global network to back us up and specialisation in vibratory equipment.”

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CONVEYOR SKIRTING

Conveyor skirting explained Thomas Greaves from DYNA Engineering explains the ins and outs of conveyor skirting: how it works, how it is designed and how it lifts productivity and safety. WHEN MATERIAL BEING conveyed enters the top of a chute, some of it is converted into dust and small particles as it falls. If dust escapes from the chute, it can lead to costly product wastage and create a health and safety issue for nearby staff and the environment. Conveyor skirting creates and maintains a seal between a chute structure and a conveyor belt, stopping dust and small particles from being able to escape the conveyor system. Conveyor skirting is usually made out of rubber strips and mechanical grips to keep it in place. It also prevents stray materials from becoming lodged between the belt and conveyor structure, which can cause abrasive wear and grooving on the belt. Skirting helps reduce dust emissions and wastage, from bulkier materials such as unrefined mineral ores, to finer materials such as sand, grain, sugar, salt and wood chips. DYNA Engineering’s General Manager Thomas Greaves.

Key conveyor skirting benefits 1. Dust suppression The primary reason to install conveyor skirting is to suppress dust. Dust poses a significant health issue as it can lead to respiratory issues and disease. Fine dust can also cause irritation, burning and damage if it gets into the eyes. In areas where dust is poorly contained, lower visibility due to dust pollution can pose a serious safety hazard for employees. Dust particles can be reduced through dust suppression systems, such as a spray bar, however a conveyor skirting seal is an effective preventative measure at the initial point. 2. Minimised material loss In a perfect world, 100 per cent of materials conveyed would arrive at their destination point. However, due to a range of factors such as

conveyor speed, incline angle, roller/ idler type (flat or troughed), material consistency, or environmental factors, materials are often spilled or blown off the belt. Effective conveyor skirting can reduce the amount of material lost by preventing spillage and airborne material wastage.

buildup require ongoing cleaning and maintenance to ensure conveyor systems run safely and smoothly. Without conveyor skirting, a system will require more maintenance which can be expensive due to cleaning labour costs and downtime from system shutdowns.

3. Reduced conveyor belt damage Without a conveyor skirting system, material can spill out and become lodged underneath the belt. Material caught between the belt and rollers will cause the belt to mistrack and become damaged. Having a conveyor skirting system in place will reduce the risk of preventable belt damage caused by material build up.

5. Increased overall productivity Conveyor skirting can increase a conveyor’s overall productivity. With health and safety incidents minimised and material loss prevented, a higher product yield can be achieved. Reduced conveyor belt damage, belt tracking issues and material build up means less time is spent on repairs.

4. Lowered cleaning costs Dust pollution, material spillage and

40 І Australian Bulk Handling Review: January/February 2020

Dynamic sealing DYNA Engineering has developed a conveyor skirting product called


Flexiseal. It automatically compensates for varying belt movements, maintains the correct pressure of the skirting rubbers on the belt, and reduces further belt wear. Flexiseal is a dynamic system that aims to maintain an effective seal where a conventional skirting seal wouldn’t. It automatically compensates for loaded and unloaded belt profiles, horizontal or vertical belt movements, and belt mistracking, keeping it in consistent contact with the conveyor belt. A unique Cam Loc clamping system uses tempered steel spring clamps to eliminate direct threaded fixings. The Cam Loc system makes replacing the seal easy while keeping the sealing element securely clamped. A low maintenance design uses a patented quick-release clamping mechanism to hold the rubber seal in place. Other benefits include: Automatic pressure control mechanism Conveyor belt wear is a common issue that plagues conventional skirting systems. It is easy to overtighten conventional systems, which puts undue pressure on the conveyor belt and results in an increase in wear. Flexiseal uses an automatic pressure control mechanism which maintains the correct pressure of the skirting rubber on the conveyor belt, making it impossible to overtighten. Consistently maintaining the correct pressure, combined with its high surface area and evenly distributed

A DYNA Flexiseal skirting system.

contact area, greatly reduces conveyor belt wear within the sealing area.

a particular issue when conveying hard and abrasive material.

Diagonal grooving channels

Quick release system

A specially designed diagonal grooving channel helps Flexiseal to reduce stray material which can become trapped under the skirting system, and transports it back to the conveyor belt. This helps reduce damage to the conveyor belt, as entrapped material can cause abrasive wear and grooving –

Flexiseal has been designed to be as low maintenance and simple as possible. On conventional skirting systems, fasteners are required to keep the skirting in place. Fasteners can seize, cause material buildup, or rip and tear off. DYNA’s design uses a quick release clamping mechanism to securely hold the rubber seal in place. When the seal eventually wears out, the quick release clamping system allows the new rubber strip to be inserted and clamped in position without adjustments.

No adjustments required

DYNA Flexiseal installed on a conveyor

On traditional skirting systems, frequent adjustments may be required to keep the skirting rubber in proximity of the conveyor belt to maintain the seal. As the skirting rubber and conveyor belt rub together, a groove begins to wear into the belt. Flexiseal does not require any adjustments, due to its dynamic design. The curved rubber sections maintain contact with the conveyor belt regardless of seal wear, belt sag, belt condition or belt mistracking.

Australian Bulk Handling Review: January/February 2020 І 41


INSIGHTS

The only thing harder than selling bulk handling solutions Grant Wellwood, General Manager for Jenike and Johanson, provides insight on the processes big companies go through when it comes to purchasing major bulk handling solutions. WE OFTEN HEAR CEOS LAMENTING the impact of ‘latent capacity’ on their businesses. As many of us are frequent visitor to their operating sites, we understand this frustration firsthand, especially as much of this productivity loss is bulk solids handling related. In most cases the problems can be attributable to baked-in design problems, to which we have proven solutions, often with payback measured in days. Yet despite this matchup, it can be hard to get traction which then creates frustration on the solution provider side as well. So, what’s going on? If you are selling solutions to address flow problems in existing operations, what you are really selling is change, the one thing large

organisations (especially mining houses) are geared to resist from all perspectives (personal risk aversion, team performance and shareholder obligation). While there is no recipe for success, the following insights may help you understand the dynamics, which is always a useful first step to devising your own pathway.

What’s in it for me? Once you can see an opportunity for a long-term solution, the first challenge is to convince someone that they actually have a problem worth solving. As irrational as it seems to outsiders, the comprehension gap between the C-Suite where the productivity pain is felt, and operations, where the root causes of ‘latent capacity’ are lived out

42 І Australian Bulk Handling Review: January/February 2020

every day, can be vast. Baked-in bulk flow problems first show up during commissioning, and after they have been conceded as ‘intractable’, operations takes control of the plant as it is. Commissioning has typically been extended (while they try and fix the baked-in faults). Once it is finally handed over, the focus is firmly fixed on revenue generation, as opposed to improvement. As the operation’s output is ramped up and its materials handling system is put under load, additional flow issues can emerge. Most operations fail to reach their nameplate capacity, and once the operation’s throughput has plateaued out, its plant performance is usually baselined. All the inherent design problems and performance


manifestations are normalised and simply accepted from that point on as ‘just the way things are around here’. Employees in large organisations seldom get into trouble for maintaining or defending the status quo, which is more than can be said for brave souls who make a conscious choice to deviate from the default option and then fail to deliver. Unlike credit, blame always finds a home. So, if I inherit responsibility for a value chain with baked-in flow problems, what’s in it for me? Change is uncertain, costly, disruptive and bulk solids flow is a notoriously risky area with unexpected consequences if it is not considered as a system. In this dynamic, the best option for an individual employee is to maintain the status quo until it becomes a burning platform for the business, in which case the drive for change and hence risk will be coming from elsewhere (Figure 1). If you can convince someone to champion your change agenda, the next thing you will encounter is the question of funding. Even if your solution has a ridiculously short payback, it is likely to have a customisation/implementation cost and resource requirement, meaning it needs to be in plan. These plans normally operate on an annual cycle, so depending on the timing of your pitch, it could be up to 12 months until your project has approved (but not guaranteed) funding. Even when they are in plan, the funds earmarked for a project to deliver your solution will be tested to confirm that the spend is absolutely necessary and that it is the best overall corporate investment option at that time, before it is finally allocated. As an aside, while out-of-plan funding is possible in theory, it is only for the bravest souls as it involves extra scrutiny and you are really pinning your future on the success of the change. Regardless of the outcome just requesting out of plan funding can cast competency doubts as it raises the question of why it isn’t in plan already. (bad planning? reactive/impulsive? hidden agenda?) Suppose you have a champion and they have been successful in getting

Figure 1: WIIFM Bingo Card

Option

support and funding for your solution in the financial year prior. Congratulations, but you have only made it to solutiondelivery base camp, with the real summit (Figure 2) now revealed dauntingly ahead of you.

Going from ‘me’ to ‘we’ – Buying by Committee As if the first two hurdles weren’t imposing enough, the days when there was a single decision maker who could sign off on your proposal have long gone. This is particularly true of bulk solids handling solutions as they tend to cut across so many functions and sit right on the organisation’s revenue lifeline, its value chain. The adage ‘companies don’t do deals, people do,’ still holds true, it’s just that you will be dealing with an incidental buying committee in order to cover all the touch points and dimensions of the proposed change. Purchase of complex solutions is usually such a rare organisational occurrence that the process involved tends to be bespoke, evolving in an organic and non-linear fashion (Figure 3). Each organisation/solution combination will have its own unique cast of characters, who all need to sign-off on your deal on behalf of their function, but some common roles are as follows:

Innovation: The champions of process change, the corporate face of complex solution considerations and the high-level custodians of the production value chain. This function constantly works with risk and uncertainty, and by definition have a mandate for continuous improvement and change. Its purpose is to convert knowledge into profit, often via the customisation and the delivery of complex solutions like yours. With a specific technology and delivery execution focus, some of the aspects of your complex solution proposal of interest to this function include: • I s this problem worth solving (in absolute and relative terms)? • I s this the best technical solution to the problem? What is the Best Demonstrated Alternative Technology (BDAT)? • Has the problem been properly framed? •W  hat does success look like (what are the testable success criteria)? •D  o we have the resources and skills to deliver this? If not, can we acquire them? • I s the value proposition realistic in our context (using our cost and financial parameters) and is it a compelling option? • I s the proposed solution futureproof?

Australian Bulk Handling Review: January/February 2020 І 43


INSIGHTS

•W  hat is the ratio of assumptions to facts? •A  re they the best in the world? What exactly is their entitlement? •W  hat are the chances they will embarrass us? •A  re there any unanticipated risks to the operations? •D  oes this option include proven project management capability? • I s the proposed project plan well considered? Does it cover: • Communication and reporting? • Risk management? • Specification? •F  actory and site acceptance testing? •S  etting criteria of issue of the certificate of completion? • I s this a case of sole source supply? If so, on what basis, and if not, who else could supply a like solution and what criteria should procurement use to test them? •W  ill it be expensive to deal with them (e.g. overseas travel costs)? • I s this a ‘first’ application of the solution? If not, is there a reference facility? If so, can we visit and speak to the operators? •H  ow much customisation is required? Do they have expertise in this area to customise a solution for us? •W  hat are the greenhouse gas implications of this proposed change for our business? •D  o they understand our business and the demands of our operating sites? Operations and maintenance: While not always the case, the most progressive organisations offer the ultimate customers of your solution a seat at the table. As the ones who often called for change, and the ones to inherit your solution, they have a very important role to play and will be interested in pragmatic issues like: • Will it make our lives easier? • What is the basis of safety? • Will we be given proper training? • I s it robust enough for mining operations?

While this cohort can appear to be taking a backseat in the purchase process, don’t be fooled as they are one of the keys to your success. Dealings with this group, your real customers, go much smoother if they are pulling for a change and championing you as the provider. Get in early and definitely don’t ignore them even though they don’t seem to have the reins of power in the transaction. Finance: The finance function is all about keeping the balance sheet in the black and minimising financial risk. The high-level focus is the financial supply chain and ensuring there is enough cash flow to keep the business operating. In relation to complex solutions, the role of the finance department typically relates to the quality of the value proposition, its position with respect to investment hurdles and its risked ranking and recommendations in relation to the alternatives. Aspects of complex solution proposals of interest typically include: •A  re the funds for this project in plan for the current year? •D  oes this project pass the organisation’s prevailing investment hurdles? •O  n a risk-adjusted basis, is this the best investment option we have right now? • I s the value proposition realistic? • I s the Net Present Value (NPV) absolute (with respect to doing nothing) or differential (with respect to the BDAT)? •D  o we need to spend money now? Can we defer any of this cost to the future? •W  hat are the cash flow implications over the life of the project? Are the financial terms acceptable? •W  hat is its accounting definition (capital improvement, sustaining capital in the face of changing feed)? •A  re there any taxation/research breaks available? If so, what do we need to do

•C  an we see it operating somewhere else and speak to its operators and maintainers? • Does it comply with our site standards? •A  re there any operating procedures and if so, are they well written?

44 І Australian Bulk Handling Review: January/February 2020

to be in a position to claim? Mining operations are essentially money-making machines. Your solution represents a modification to its workings, so finance team approval can be the most difficult to get, even with enthusiastic recommendations from the proponent and rest of the buying committee. Larger or more disruptive purchases often need personal approval from the Chief Financial Officer. They expect to see a comprehensive proposal detailing the expected total value received, the investment required, and comparisons with BDAT and the donothing cases. Financial metrics such as NPV and internal rate of return, as well as the sensitivity of the same to the input assumptions, may also be required. The option can be put to the board or capital approval committee in the form of a capital appropriation request. Procurement: If the finance function is all about keeping the balance sheet in the black, and minimising financial risk, procurement is about spending the allocated money wisely. Focused on increasing shareholder value by exercising procurement expertise and leveraging group scale, the procurement function are the supply gatekeepers who ensure purchases comply with governance, procedural fairness and best value requirements. Matters of interest to the procurement team include: •A  lignment of proposals with the organisation’s core values and business objectives Figure 2: Journey from Solution Identification to Deal


• Financial security of the supplier • The trade-off between price and value •R  ole in the supply chain (are they a direct manufacturer of goods, or an authorised agent/distributor?) • Ease of doing business •A  vailability of competent personnel to support the goods and/or services supplied •M  aintenance of appropriate health and safety and quality assurance systems and processes •A  menability to trade on the basis of the organisation’s standard terms and conditions •P  olicies that support fair competition and integrity, require adherence to applicable laws, standards and regulations and prohibit giving or receiving bribes, with a process for ensuring compliance. Provided all these foundation requirements are satisfied, the actual supply of the solution is usually tested competitively and awarded on the basis

of a weighted score of the following criteria: •A  re they technically compliant with all the bidding requirements? •D  o they satisfy the internal customer’s stated needs and required standards? •D  o they meet the values articulated in organisation’s business conduct? •A  re service contracts (capability, terms) favourable? The recommended solution purchase option then usually goes to the legal team for a once over from their unique perspective before the project is given an identity in the accounting system and the successful supplier is issued with a purchase order. Legal/Intellectual Property (IP): The role of this specialised functional group is to make sure the proposed deal is legally compliant, covers all eventualities and that any commercial advantage that may arise is enjoyed to the maximum and protected as far as possible from fast followers and

competitors. They sometimes come in early to set flags for the procurement team but more typically come in during the competitive test. The aspects of interest include: •A  re all the parties involved working on like terms and covered by suitable agreements? • I s the supplier in a position to guarantee the freedom to operate in all jurisdictions where we may want to use it? • I s there likely to be any new IP generated as a result of customising a complex solution? If so, can we own or control it or at least have free use? • I f there are requests to change our standard terms and conditions can we accept them and/or trade them off for valuable concessions elsewhere? The new IP ownership clause in a schedule of standard terms and conditions is often the most contentious and can bog your deal down or even result in it being rejected, but you can

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INSIGHTS

Figure 3: The organic process of buying by committee

prepare for it. The situation goes like this: Customer’s perspective: The implementation of this generic solution in our operation will involve solving many problems. Every time a problem is solved, a new IP is generated. As we are paying for commercial rates for this work, we should own it. We don’t want to pay for suppliers to learn and/or give our competitors a free kick. Supplier’s perspective: Customisation is a standard part of the solution implementation process and we want to capture and incorporate these learnings while retaining our freedom to operate. These learnings are only possible off the back of our background IP and have no value without it, so they belong to us. Possible compromise: Grant the customer a perpetual royalty-free licence to use any project IP generated, but only in their own operations. You should also seek to extend this to future project IP, as there could be additional improvements once your solution clocks up some run-time. Information Technology (IT): Last, but definitely not least, is the IT team, custodians of the organisation’s digital circulation system. Nearly every complex solution (even bulk solids handling ones) involves

software, hardware and connection to the organisations existing IT infrastructure. They have an important role to play ensuring any new solutions are compatible with the organisation’s current and future IT infrastructure. Consider the following questions: • I s the software compatible and who will maintain it? •W  ill it be expensive/difficult to support? • Do they offer remote support? •W  hat does the hardware landscape look like? •W  ill this solution architecture fit in with our existing IT system? •D  oes it represent a security threat to our existing IT infrastructure? •D  o we have the hardware and knowhow to support it? • I f it has sensors, who sees/owns the data generated? • Is it future proof? While the functions that comprise the buying committee members all have the same corporate goal and something unique to contribute, the resulting purchase process can be dogged by functional conflicts rooted in struggles for power, resources and budgets. Each group involved will feel compelled to make a material contribution (even if it is not needed) in order to help justify their existence.

46 І Australian Bulk Handling Review: January/February 2020

Compounding this ‘busy work’ impact further is the fact that many organisations seldom deal with complex solution purchases so are not set up to streamline the purchase process. One of the challenges here is role clarity as some of these functions have overlapping capabilities that can lead to demarcation disputes. In addition, while many solutions need support functions, they are not staffed for complex solutions. As illustrated, considering complex solutions requires a lot of extra effort on the part of many corporate functions and from individuals who did not have it in their annual plans. As a result, your proposal can remain ‘under active consideration’ for months, waiting to get input from key resources and caught between the gaps in a sort of no man’s land (Figure 2). Left to their own devices, these functions typically regress to their lowest common denominators, the things they all agree on which are to avoid risk, move cautiously, reduce disruption, and save money. Given they already have a status-quo solution that is most probably ‘good enough’, the final ‘decision’ is often no change, no deal.

‘Success has many fathers, but failure has but one’


On most occasions, all the functions involved will be trying to manage their risk exposure and hedge their bets around this idiom. If it is a screaming success, all the functions will want to be seen as fathers with the bragging rights to say how they ‘picked this winner early’ and went above and beyond, cutting through the corporate red tape with their machete in order to make it happen. Conversely, if it is deemed a failure, they want to be in a position to say how they ‘always harboured reservations’ and despite raising them on numerous occasions were forced to be reluctant participants. In summary, what often matters more to corporate decision makers is not the outcome itself, rather the ability to defend their decision whatever the outcome might be. Engineering the corporate memory to keep both options open is a difficult balancing act but awareness of this dynamic helps explain some of the contradictory behaviour and backflips you experience during the decision-making stage.

So…what can we do? Granted, this is a pretty grim picture but complex solution deals are still getting done, so what is the secret? The science of business is a discredited concept so there is no recipe for success, but you may find some of the following points useful as you deal with the new purchasing dynamic: •D  on’t focus on your solution, you need to convince people that they have a problem and that they may have overlooked something. Lead to your solution not with it. •G  et grass-roots support from your ultimate customer – the host operation. •S  eek out suggestions and ideas you can incorporate into the customisation proposal that will improve performance but more importantly increase ownership and the pull for change, •B  e honest with the risks as well as the rewards. All change involves risk so glossing over it and presenting an unbalanced picture erodes credibility and trust. The benefit of being honest is that the mitigations are something that can be attributed to the buyer increasing ownership for the final solution. •O  ffer a vivid and compelling vision of the future that people can get excited about and champion to their colleagues. Conclusion: Designing for bulk solids flow is a common design oversight. It features prominently in many complex solutions pitched at addressing the serious issue of latent capacity. While such solutions are still being purchased, the techniques of the past centred around identifying and wooing a single senior decision maker are no longer valid. Defending the status-quo and deferring to the default choice is usually an inferior outcome for a business with latent capacity. However, it feels like a decision and insures those involved (and their functional department) against a catastrophically bad outcome. This is a recognised cognitive bias called ‘Defensive DecisionMaking’. It is not possible to be prescriptive about the best sales approach to take, however, having some insight into the buying side process helps you understand what is going on and why their task is much harder than yours. If you are on the buying side, I share your frustration and pain.

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TECHNICAL PAPER

Investigation of loads acting on flow isolating gates in bulk solids storage bins Professor Alan Roberts from TUNRA Bulk Solids combines an analytical review of gate load determination with an experimental study employing a large, pilot scale mass-flow bin handling iron ore to examine the design of mass flow bins for train loading. STORAGE BINS FOR BULK SOLIDS handling operations rely on flow isolating gates to prevent outflow of bulk solids during initial bin filling from the empty condition, as well as during periods of stoppages in the plant operation. While in some cases slide gates may be employed in a flow 'throttling' mode to adjust the outflow, this action is not recommended in view of the negative influence this may have on the distribution of bin wall loads due to resulting eccentricities in the bulk solids discharge flow patterns. For efficient flow control, the gate must be fully opened during the plant operation and a flow rate controlling device, such as a belt or vibratory feeder, being employed to achieve the required discharge feed rate. The motivation for the study presented in this paper concerns the design of isolating gates in load-out bins such as those employed in the iron ore and coal industries for the filling of bulk rail wagons while the train is in continual motion. The bins incorporate mass-flow hoppers which utilise slidetype flow isolating gates in conjunction with swing action, inclined chutes fitted with clam shell flow trimming gates to control the discharge of bulk solids into the moving train wagons. The discharge control chutes are fitted below the flow isolating slide gates. During the filling operation, the flow controlling clam shell chutes are held in the raised position to allow sufficient head room for the train locomotive to pass underneath. Once this happens, the chutes can then be lowered

to a position just clear of the top of the determination, it is important that the rail wagons. The isolating gate is then subject of gate loads be investigated. This opened, and the continuous wagon filling is the motivation for this paper, the aims operation commences. The bins operate of which are summarised as follows: between 'high' and 'low' fill levels in 1. E  xamine the influence of surcharge conjunction with bin loading conveyors. loads and impact loads during the bin By way of background, the of Bysubject way of background, thefilling subjectoperations. of gate loads is intrinsically linked to the study of feeder lo subject which has received significant research attention as indicated by the selected samp gate loads is intrinsically linked to the 2. O  utline experimental studies to references [1-3]. In essence, this research has emphasised the importance of treating the mass study of feeder loads, a subject which has measure gate loads on a pilot scale hopper and feeder as an integral, interactive system in which the bulk solids stress fields in the h influence the feeder loads and the drive torques and powers. It has been received significant research directly attention laboratory binassociated and corroborate the established that as a result of the change in stress states in the feed hopper, the vertical loads as indicated by the selected sample results with the theoretical results. on a feeder during outflow, are usually significantly lower than the loads acting when the durin of references [1-3]. In essence, this 3. E with xamine thenot influence of bulk solids initial filling of the hopper the feeder operating. The reduction in loads from filling to ru the order of 80% have been recorded. following bin loading. research has emphasised theinimportance settlement of treating the mass-flow hopper 4. E  stablish gate load analysis procedures For binand flow isolating gates, the gate loads correspond to the initial filling case of feeders. The are influenced the degree of compressibility of themethods bulk solids and degree rigid feeder as an integral, interactive system primarily bywhich incorporate improved stiffness of the gate. As discussed in Section 3 of this paper, the Australian Standard AS3774 in which the bulk solids stress in some guidance forfor selection the most appropriate [4],fields provides gate loadof determination by specifying appropriate so-calle based on notional bulk solid and gate stiffness levels. In view of the w the hopper directly influencevalues the feeder value ofcompressibility 'j'. varying influence the values of “j” has on the gate load determination, it is important that the s loads and the associated drive oftorques gate loads and be investigated. This is the motivation for this paper, the aims of which are summ as follows:that powers. It has been well established 2. Review of mass-flow hopper and as a result of the change in stress in thegate-load (i) states Examine influence ofanalysis surcharge loads and impact loads during the bin operations. The gate loads of a mass-flow hopper the feed hopper, the vertical loads acting (ii) Outline experimental studies to measure gate loads on a pilot scale laboratory bi on a feeder during outflow are usually are derived from wall load theory, corroborate the results with the theoretical results. significantly lower than the loads relevant aspects of which are now (iii)acting Examine thethe influence of bulk solids settlement following bin loading. (iv) Establish load analysis procedures which incorporate improved methods for sele during the initial filling of the hopper with gate reviewed. of the most appropriate value of ”j”. the feeder not operating. The reduction in of Mass-Flow and Gate Load Analysis loads from filling to running 2. inReview the order 2.1Hopper Mass-flow load model The gate loads of a mass-flow hopper are derived from wall load theory, the relevant aspects of of 80 per cent have been recorded. Considering the equilibrium of the model are now reviewed. For bin flow isolating gates, the gate presented in Figure 1, the following 2.1 Mass-Flow Load Model loads correspond to the initial filling D case of feeders. The loads are influenced ps primarily by the degree of compressibility of the bulk solids and degree rigidity zh p vh or stiffness of the gate. As discussed in a t Section 3 of this paper, the Australian zg dzh hh Standard AS3774-1996 [4], provides some pnh guidance for gate load determination pvh+ dpvh dW by specifying appropriate so-called 'j' values based on notional bulk solid compressibility and gate stiffness levels. Gate In view of the widely varying influence B the values of 'j' has on the gate load Figure 1. Schematic of mass-flow hopper load model.

13th International Conference on Bulk Materials Storage, Handling 9-11 July 2019, Qu

48 І Australian Bulk Handling Review: January/February 2020


p vh ttt ppp nhpvh tt t ct a low value of “jâ€?, such as j = 0.1, the design willvhalmost beppfar too conservative ď łď łp1vh1nhnhnht t ď ł 1 nhnh ď ł1 pp nhp nrealistic values of the computed loads. This provided the motivation for the test ď ł1 ď ł1 nhnh pnh ď łď ł 11 ď łď ł 11 ď łď ł 1ď ł ď łď ł 1ď ł w described. 11 11 ď ł1

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t Bin and Test Procedure (a) Active Stress State (b) Passive Stress (a) Active State Stress State (c) Active/Passive (b) Stress Passive Stress State (c) Active Stress State (b) Passive Stress (a) Active State Stress State (c) Active/Passive Passive Stress State (c) State (b) Stress or this research is shown in Figure 3. Figure (a) 3(a) shows the bin geometrical details State2. Mass-flow hopper stress fields. Figure 2. Mass-flow hopper stress fields. Figure Mass-flow hopper stress fields. Figure 2. Mass-flow hopper stress fields. shows the test set up with the bin being filled with iron ore. TheFigure bin 2. is of ‘Perspex’ brium ofConsidering the model presented the equilibrium in Figure of 1, thethe model following presented differential in Figure equation 1, the following is differential equation is ps with = surcharge pressure acting on the Îą1 hopper section ps = [kPa]. surcharge pressure acting on the hopper section [kPa]. prising a five section, variable geometry mass-flow hopper half-angles = derived:differential equation is derived: for the to be fully acting emptied and with feeder loads andacting specifies that the section [kPa]. ppssw=hopper pressure on the hopper surcharge pressure on the hopper =surcharge surcharge pressure at switch level [kPa].section ppssw==[kPa]. surcharge pressure at switch level [kPa]. and Îą3 = Îą4 =đ?‘‘đ?‘‘đ?‘‘đ?‘‘Îą5 =đ?‘—đ?‘— đ?‘?đ?‘?9.84o. The bin is mounted then on three support columns, each of pprefilled = surcharge pressure at switch level [kPa]. = average surcharge pressure at level [kPa]. sw fromvertical the empty condition. of 'j' bevertical selected asswitch follows: surcharge pressure acting value atppsw switch = level [kPa]. surcharge pressure acting at switch leve vh = average vh đ?‘—đ?‘— đ?‘?đ?‘? = đ?›žđ?›ž cells to + = đ?›žđ?›ž (1) (1)vertical pysw average surcharge pressure acting atpysw switch = average levellevel vertical [kPa]. surcharge pressure acting at switch leve vh = vh on−load the measurement =For switch [m]. = switch (â„Ž (â„Ž − đ?‘§đ?‘§ ) the bin load to be measured. đ?‘§đ?‘§ ) đ?‘‘đ?‘‘đ?‘‘đ?‘‘ enable The 'passive' orlevel 'arch' stress field isof an the (a) j = 0.1 for[m]. very incompressible ypsw = switch level [m]. ypsw = switch level [m]. vh = vertical pressure [kPa]. vh = vertical pressure [kPa]. l load cell was developed comprising a flat plateimportant mounted on three transducers property thatload is employed materials stored above stiffly supported ppvh = vertical pressure [kPa]. ppvh = vertical pressure [kPa]. pressure acting [kPa]. (2) nh = normal(2) nh = normal pressure acting [kPa]. ][ ] + [đ?‘?đ?‘? − đ?‘?đ?‘? = ] [ ] + [đ?‘?đ?‘? − in feeder load determination and load feeders. ptnh= =shear normal [kPa]. pt nh= =shear normal pressure attached to a base plate. Adjusting screws were incorporated topressure enable the clearance stress [kPa]. acting stress [kPa]. acting [kPa]. = shear stress [kPa]. tď łď€ą==(b) shear [kPa]. outlined in the work of j =stress 0.45 for moderately where: major consolidation stress [kPa]. major consolidation stress [kPa]. r outlet and gate surface to đ?‘Ąđ?‘Ąđ?‘Ąđ?‘Ąđ?‘Ąđ?‘Ą beď Śset. The gate load control, celltď łunit is completely independent  =as đ?‘Ąđ?‘Ąđ?‘Ąđ?‘Ąđ?‘Ąđ?‘Ą ď Ś ď ł = major consolidation stress [kPa]. ď ł = major consolidation [kPa].   [3]. the(3)bin and gate load cell compressible materialsstress stored above ⌊đ?‘˜đ?‘˜ (1 + loading )− đ?‘—đ?‘— = 1⌋(đ?‘šđ?‘šand + 1) ⌊đ?‘˜đ?‘˜load (1 + settlement ) − 1⌋ (3) of Roberts e.+ 1)For the stages the tests, đ?‘Ąđ?‘Ąđ?‘Ąđ?‘Ąđ?‘Ąđ?‘Ą đ?›źđ?›ź đ?‘Ąđ?‘Ąđ?‘Ąđ?‘Ąđ?‘Ąđ?‘Ą đ?›źđ?›ź 3. Hopper Gate Loads 3. Hopper Gate Loads TheLoads 'active/passive' stress field3. Hopper Gate flexibly supported feeders. 3. Hopper Gate Loads at a minimummclearance of approximately 0.5 while making surebinthat the gate For bin mm, and gate load design, the initial filling For andbin subsequent and gate load refilling design, conditions the initial arebin of filling primary and subsequent refilling c pper flow symmetry factor hopper flow symmetry factor [-].factor [-]. m == [-]. hopper flow symmetry occurs when the 'passive' state is (c) j= 0.9 for very compressible For bin and gatethe load design, thestate initial bin filling For andbin subsequent and load refilling design, conditions the initial are bin ofcase, filling primary and subsequent refilling concern. Since active stress depicted in partly Figure concern. 2(a) Since isgate perceived the active tostress dominate state in depicted this in Figure the 2(a) is perceived to cd or plane with flow or wedged shaped = 0 for hopper planewas flow [-]. orimportant wedged shaped hopper [-]. tact themmbin. It the independence of the bin and gate load active stress in Figure concern. Since isthe perceived the activetostress dominate depicted this case, ingate Figure the 2(a)on is perceived to d foraxi-symmetric plane floworor wedge-shaped developed as shown in Figure 2(c). An 2(a) materials stored above softly supported or axi-symmetric or conical m= = 10hopper for [-]. conical hopper [-].concern. selection Since of thethe parameter “jâ€? state has adepicted significant selection influence ofon the parameter magnitude “jâ€?ofstate has the ain calculated significant influence the magnitud hile, at the same time, simulating a “stifflyâ€? supporting gate. selection of the parameter “jâ€? has a significant selection influence of on the the parameter magnitude “jâ€? of has the a calculated significant gate influence on the magnitud all friction anglehopper [degrees]. ď Śđ?‘¤đ?‘¤ =[-]. wallm friction angle [degrees]. loads. The Australian Standard AS3774-1996 [4] loads. “Loads The on Australian Bulk Solids Standard Containersâ€? AS3774-1996 combines [4] gate “Loads on Bulk Solids Con = 1 for axi-symmetric or example of this is 'load cushioning' where feeders. â„Ž

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loads. The Australian AS3774-1996 [4]loads. “Loads Theon Australian Bulk Solids Standard Containersâ€? AS3774-1996 combines [4] gate “Loads Solids Con pper half-angle [degrees]. đ?›źđ?›ź = hopper half-angle [degrees]. loads with feeder loadsStandard and specifies that the value loads of “jâ€? with befeeder selected loads as and follows: specifies that the value of “jâ€? on be Bulk selected as follo hopper never emptied completely, It is that for completely charge pressure conical [kPa]. ps =hopper surcharge [-]. pressure [kPa]. loads withthe feeder loadsisand specifies that the value loads of “jâ€? withbefeeder selected loads as noted and follows: specifies thata the value of “jâ€? be selected as follo 3 3 = bulk specific.250 weightď Ś[N/m ď §ď€ ď€˝ď€ ď ˛ = bulk specific weight ]. ď Ś friction =g].wall angle[N/m [degrees]. theincompressible arched, 'passive' stress bulk solidmaterials and rigid gate, w .250 (a)soj =retaining 0.1 for very materials stored (a) above j = incompressible 0.1stiffly for very supported incompressible feeders. stored above stiffly supp k density [kg/m3]. ď ˛ = bulk density [kg/m3]. (a) jj = for incompressible materials stored (a) above jj = 0.1 stiffly for supported feeders. materials storedstored aboveabove stiffly flexi supp đ?‘?đ?‘? a = hopper half-angle [degrees]. when being refilled. Another case value ofincompressible j =0supported in Equation (3) reduces (b)state = 0.1 0.45 forvery moderately compressible materials (b)stored = the 0.45 above forvery moderately flexibly compressible feeders. materials = pressure ratio [-]. kh =đ?‘?đ?‘?đ?‘›đ?‘›â„Ž = pressure ratio [-]. (b) j = 0.45 for moderately compressible materials (b)stored j = 0.45 above for moderately flexibly supported compressible feeders.materials stored above flexi 0.400

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(c) j = 0.9 for very compressible materials stored(c) above j = 0.9 softly for supported very compressible feeders. materials stored above softly suppo softly suppo It is noted that for a completely incompressible bulk It issolid notedand thatrigid for agate, completely the valueincompressible of j =0 in Equation bulk solid and rigid gate, the v It notedThe that for a“hydrostaticâ€? completely incompressible It notedand that for “hydrostaticâ€? agate, completely of j given =0 in Equation bulk density [kg/m3]. associated downward settlement of given as:the valueincompressible p= (3)isreduces to the load given by: bulk (3)issolid reduces torigid the load by: bulk solid and rigid gate, the v 2.2 Stress Fields (3) reduces to the “hydrostaticâ€? load given by: (3) reduces to the “hydrostaticâ€? load given by: Pnh y developed The two stress principal, fields in fully a hopper developed are the stress “activeâ€? fields stress in a hopper state as are shown the “activeâ€? in stress state as shown in kh = = pressure ratio [-]. pvh the bulk solid as it approaches its critical passiveâ€?Figure stress 2(a) state as0.830 the shown “passiveâ€? in Figure stress 2(b).state Theas“activeâ€? shown in state Figure of stress 2(b). The “activeâ€? state of đ?›žđ?›žđ?‘§đ?‘§ stress 0.830 ď Śand ď Ś (4) đ?‘?đ?‘? = đ?‘?đ?‘? + đ?‘?đ?‘? = đ?‘?đ?‘? + đ?›žđ?›žđ?‘§đ?‘§ đ?‘Łđ?‘Łâ„Žđ?‘–đ?‘– đ?‘ đ?‘  â„Ž đ?‘Łđ?‘Łâ„Žđ?‘–đ?‘– đ?‘ đ?‘  â„Ž vertical consolidation condition results in load the initial normally filling of accompanies ap hopper from the initial the empty filling condition of apressure hopper and is from characterised the empty by condition and is characterised vh = average (4) đ?‘?đ?‘?đ?‘Łđ?‘Łâ„Žđ?‘–đ?‘– = đ?‘?đ?‘?đ?‘ đ?‘  + đ?›žđ?›žđ?‘§đ?‘§â„Žby đ?‘?đ?‘?đ?‘Łđ?‘Łâ„Žđ?‘–đ?‘– = đ?‘?đ?‘?đ?‘ đ?‘  + đ?›žđ?›žđ?‘§đ?‘§â„Ž ď Ś on stress,theđ?œŽđ?œŽ10.792 major , acting consolidation substantially stress, in the đ?œŽđ?œŽ vertical , acting direction substantially and curving in the vertical away direction and curving away 1 acting on ď Ś slice at depth zh [kPa]. pnh = With the corresponding transfer to the hopper walls and hence, 0.792 S5walls rection lines slightly intersect as the stress the hopper direction lines as shown intersect in Figure the hopper 2(a). walls as shown in Figure 2(a). pressure ratio given as: With the corresponding pressure ratio given as: S5 pressurestate ratioof given as: as With the corresponding given as: be quite corresponding normal pressure actingWith on the corresponding a zone of 'passive' stress Whilepressure a gate ratio will generally 0.704 ď Ś = 0.704 ď Ś 5= o a đ?‘?đ?‘?solid đ?‘Ąđ?‘Ąđ?‘Ąđ?‘Ąđ?‘Ąđ?‘Ą đ?›źđ?›ź đ?‘?đ?‘?đ?‘›đ?‘›â„Ž đ?‘Ąđ?‘Ąđ?‘Ąđ?‘Ąđ?‘Ąđ?‘Ą đ?›źđ?›ź đ?‘›đ?‘›â„Ž such as occurs Theo“passiveâ€? when there state is any of stress downward occurs movement when there of is the any bulk downward solid such movement as of the bulk 4stress wall [kPa]. illustrated Figure 2(c). đ?‘˜đ?‘˜â„Žđ?‘–đ?‘– = in = đ?‘˜đ?‘˜â„Žđ?‘–đ?‘– = đ?‘?đ?‘?đ?‘›đ?‘›â„Ž = (5) đ?‘?đ?‘?đ?‘?đ?‘?đ?‘›đ?‘›â„Ž đ?‘Ąđ?‘Ąđ?‘Ąđ?‘Ąđ?‘Ąđ?‘Ą đ?›źđ?›ź ď Ś đ?‘Ąđ?‘Ąđ?‘Ąđ?‘Ąđ?‘Ąđ?‘Ą đ?›źđ?›ź ď Ś đ?‘Ąđ?‘Ąđ?‘Ąđ?‘Ąđ?‘Ąđ?‘ĄIn đ?›źđ?›ź+đ?‘Ąđ?‘Ąđ?‘Ąđ?‘Ąđ?‘Ąđ?‘Ą đ?›źđ?›ź+đ?‘Ąđ?‘Ąđ?‘Ąđ?‘Ąđ?‘Ąđ?‘Ą n even9.84 occur duringdue discharge. to load settlement It can evenasoccur discussed due toinload Section settlement 6 of this as paper. discussed In in Section đ?‘Łđ?‘Łâ„Ž paper. đ?‘Šđ?‘Š đ?‘Šđ?‘Š đ?‘˜đ?‘˜â„Žđ?‘–đ?‘–6 of = this = đ?‘Ąđ?‘Ąđ?‘Ąđ?‘Ąđ?‘Ąđ?‘Ą đ?‘˜đ?‘˜â„Žđ?‘–đ?‘– = đ?‘?đ?‘?đ?‘?đ?‘?đ?‘Łđ?‘Łâ„Ž = đ?‘Ąđ?‘Ąđ?‘Ąđ?‘Ąđ?‘Ąđ?‘Ą (5) đ?‘?đ?‘?đ?‘Łđ?‘Łâ„Ž đ?›źđ?›ź+đ?‘Ąđ?‘Ąđ?‘Ąđ?‘Ąđ?‘Ąđ?‘Ą ď Ś đ?‘Ąđ?‘Ąđ?‘Ąđ?‘Ąđ?‘Ąđ?‘Ą đ?›źđ?›ź+đ?‘Ąđ?‘Ąđ?‘Ąđ?‘Ąđ?‘Ąđ?‘Ą ď Ś đ?‘Łđ?‘Łâ„Ž

= surcharge pressure [kPa]. of the 'active/passive' stress state occurs to the 'hydrostatic' load given by: ppsacting verage vertical pressure on slicevertical at depth pressure zh [kPa]. acting on slice at depth (c) zh [kPa]. vh = average j = 0.9 for very compressible materials stored(c) above j = 0.9 softly for supported very compressible feeders. materials stored above 3 wall [kPa]. rresponding normal pressure acting on specific wallnormal [kPa].weight pressure acting g p=nhp=gcorresponding = bulk [N/mon ]. when filling from the empty condition. With the corresponding pressure ratio

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0.506

Fill Height = 1.866

13 International Conference on Bulk Materials Storage, Handling and Transportation 13 International Conference on Bulk S4 loads increase as the instress the normal field switches wall from as the stress “peakedâ€? fieldor switches “activeâ€? from stress the “peakedâ€? or “activeâ€? 4 wall = loads 2.2 Stress fields 3. Hopper gatestress loads S4“passiveâ€? July Handling 2019, Queensland, Australia 13 International Conference on Bulk Materials 9-11 Storage, and Transportation 13 International Conference on Bulk 4state =todepicted passiveâ€? state the “archedâ€? in Figure “passiveâ€? 2(b). For state thedepicted in Figure stress state, 2(b). the Formajor the “passiveâ€? stress state, the major o a 9-11 July 2019, Queensland, Australia 84, for each o 0.527 ď Ś The 0.527 two fully-developed stress binthe and load design, the initial 'stiff', there is considerable uncertainty consolidation arch stress stress, line isprincipal, đ?œŽđ?œŽ1 , for each in magnitude arch stressaround line is constant the arch but in magnitude varies For around archgate but varies 9.84 1 ď Śconstant “passiveâ€? in stress direction. stateOnce is established, it remains stress in state a stable is established, conditioniteven if thein a stable condition even if the fields inthe a “passiveâ€? hopper are the 'active' stressremains bin filling and subsequent refilling as to the degree of compressibility of efore thedischarge hopper isisemptied. stoppedThe before only theway hopper that the is emptied. “activeâ€?The stress only state waycan thatbethe “activeâ€? stress state can be e hopper re-established to be fully emptied is for the and hopper then refilled to be fully from emptied the empty and condition. then refilled Thefrom the empty condition. The state as shown in Figure 2(a) and the conditions are of primary concern. Since the bulk solid during the bin filling a3 = S3 o “passiveâ€? a3 =is'passive' stress field anorimportant “archâ€? stress property fieldthat is is an employed important inproperty feeder that load is employed in feeder load S3 .84 stress state as shown in Figure the active stress state depicted in Figure operation. While the 'safe', conservative o d control,determination as outlined in and the load work control, of Roberts as outlined [3]. in the work of Roberts [3]. 0.350 ď Ś 9.84 ď Ś 2(b). 0.350 The 'active' state of stress normally 2(a) is perceived to dominate in this case, approach is to select a low value of 'j', stress Theoccurs “active/passiveâ€? when the “passiveâ€? stress fieldstate occurs is partly whendeveloped the “passiveâ€? as shown state is in partly developed as shown in a2 =field accompanies the initial filling of awhere the selection of the parameter 'j' has a such as j = 0.1, the design will almost S2 le of this Figure is “load 2(c). cushioningâ€? An example where of this the is hopper “load cushioningâ€? is never emptied completely, the hopper is never emptied completely, ď ł 2 = o 8.03 S2refilled. ď Ś thestate ostress hed, “passiveâ€? so 0.256 retaining arched, when “passiveâ€? being stress Another state when caseis being of the refilled. Another case of the on the magnitude of hopper from the empty condition and significant influence be far too conservative due to the high, 8.03 0.256 ď Ś the s state occurs when filling stress from state empty occurs condition. when filling The from associated the empty downward condition. The associated downward a1 = “active/passiveâ€? characterised by the major consolidation the calculated gate loads. The Australian unrealistic values of the computed loads. S1 = 0.200ď Ś 5.88o a1 stress, S1 Cell acting substantially in the vertical Standard AS3774-1996 [4] 'Loads on Bulk This providedcondition the motivation the test settlement of the bulk solid as it approaches its critical consolidation results infor load transfer o 5.88 ď Ś Conference on Bulk Materials13Storage, 130.256 International International Handling Conference and Transportation on Bulk Materials Storage, Handling and Transportation 9-11 July 2019, 9-11 July 2019, Queensland, Australia direction and curving away 1 slightly asQueensland, Australia Solids Containers' combines program that is now described. to the hopper walls and hence, a gate zone loads of “passiveâ€? state of stress as illustrated in Figure 2(c). the stress direction lines intersect the ps s ps s ps p st Bin Arrangement (b) Filling BinppDuring Test Run p ss ps p hopper walls as shown in Figure 2(a). s Figurestate 3. Pilot scale test bin. The 'passive' of stress occurs when there is any downward movement d was dryofiron ore.solid Thesuch quantity of ore used for the experiments was 767 kg, the the bulk as during discharge. It can even occur to load ity following the filling of the bindue being 2.03 t/m3. As shown in Figure 3(b), the binpppvhvh t vh ppsw t t as discussed Section of skip being hoisted and tipped to the bin ctangular settlement skip containing the iniron ore,6 the pswsw pp vh vh p p this paper. In thisWhile case thesome convergence nhnh sing an overhead crane. minor variations in thevhloading pnhp ttt cycle occurred of the downward movement of the ď ł 1 to the next, the average bin loading rate was, approximately 30 toppnh35 t/h. This ď ł1 ď ł1 pnh nh bulk solids in the hopper causes an yysw uired for the determination of the impact loads during the bin filling operation. yswsw ď ł1 increase in the normal wall loads as the ď ł1 ď ł1 stress field switches from the 'peaked' or 'active' stress state to the 'arched' 13th International Conference on Bulk Materials Storage, Handling and Transportation (a) Active Stress State (b) Passive Stress State (c) Active/Passive Stress 9-11 July 2019, Queensland, Australia 'passive' state depicted in Figure 2(b). State For the 'passive' stress state, the major Figure 2. Mass-flow hopper stress fields. consolidation stress, for each arch stress ps = surcharge pressure acting on the hopper section [kPa]. line is constant in magnitude around the p sw = surcharge pressure at switch level [kPa]. arch but varies 1 in direction. Once the pvh = average vertical surcharge pressure acting at switch level [kPa]. 'passive' stress state is established, it ysw = switch level [m]. remains in a stable condition even if the pvh = vertical pressure [kPa]. pnh = normal pressure acting [kPa]. discharge is stopped before the hopper is t = shear stress [kPa]. emptied. The only way that the 'active' ď łď€ą = major consolidation stress [kPa]. stress state can be re-established is th

3. Hopper Gate Loads For bin and gate load design, the initial bin filling and subsequent refilling conditions are of primary concern. Since the active stress state depicted in Figure 2(a) is perceived to dominate in this case, the Australian Bulk Handling Review: January/February 2020 І 49 selection of the parameter “jâ€? has a significant influence on the magnitude of the calculated gate loads. The Australian Standard AS3774-1996 [4] “Loads on Bulk Solids Containersâ€? combines gate loads with feeder loads and specifies that the value of “jâ€? be selected as follows:


purpose of this final stage of the test was to observe the potent stress field change from active to passive states as a result of small, of the iron ore in the bin. This particular information is of the importance of a passive stress state in controlling feeder During each test run, the net bin loads and gate loads were recorded using a data logger in conjunction TECHNICAL PAPER During each 5. test run,the thecommencement net bin loads andofgate weretorecorded using a Predicted Performance with a laptop computer. The loads were recorded from binloads loading the with a laptop computer. The loads were recorded from commencem As an aid to the areview thein measured testthe results, a select of the operation. The load recording continued on aofperiod of approximately Duringcompletion each test run, thebin netfilling bin loads and gate loads were recorded using dataforlogger conjunction completion thegate bin fillingdue operation. The load recording continued on for characteristics of the test binloading of Figure 3iron are presented. Th hours in order to measure thewere changes in the from bin of and loads to the ofto thethe ore with a2 laptop computer. The loads recorded the commencement of settlement bin 2 hours in order to measure the inapproximately the bin and gatea specific loads duefocus to the established bin andachanges feeder theories with o in the of bin. completion the bin filling operation. The load recording continued on for periodload of in bin the bin. AS3774-1996 following flow properties of the iron or 2 hours in order to measure the changes in the and gate loads due to[4]. the The settlement of the iron ore pilot scale test bin assumed. lowering the gate loadarecell in order to record the in the The bin. final stage of the tests involved progressivelythe final stage of the tests involved progressively lowering the gate load 4. Pilot scale test bin and test bin being t/m3.asAsthe shown in The Figure in view of gate the importance of a The decrease in 2.03 gate load clearance between the design bin outlet and the surface increased. 3 decrease in gate load as the clearance between the bin outlet Average bulk density ď ˛ = 2.03 t/m purpose of this final stage of the test was to observe the potential decrease in gate cell load due to the The final stage of the tests involved progressively lowering the gate load cell in order to record the procedure 3(b), the bin is filled using a rectangular passive stress state in controlling feeder and the ga opotential decrease purpose of this final stage of the test was to observe the Wall friction angle ď Śđ?‘¤đ?‘¤ =albeit 25 very stress field change active to between passive states as outlet aloads resultand of the the downward in gate load as from the the bin gate surfacemovement, increased. The The test bin used for this research is decrease skip containing the clearance iron ore, the skip and drive powers. stress field change passive states asto a result of the downwa small, of final the iron oreofinthe thetest bin. This particular is active of Bin relevance toQfeeder design in view purpose of this stage was to observe theinformation potentialfrom decrease into gate cell load the fill rate = 35due t/h m shown in Figure 3. Figure 3(a) shows being hoisted and tipped to the bin small, iron the bin.and This particular information thechange importance a passive stress states state inasof controlling feeder loads drive powers. stress of field fromof active to passive a the result ofore the in downward movement, very Effective angle of albeit internal frictionisď ¤of= relevance 50o the bin geometrical details while Figuresmall, of loading an overhead 5.isPredicted performance of the importance of passive stress stateload-out in controlling andhdd the ironposition ore in theusing bin. This particular information ofarelevance toheight, feeder design inskip view Drop tofeeder fillingloads surface 3(b) shows the test set up with the bin of the 5. crane. While in As an aid and toParameter the review the measured Predicted importance ofPerformance a some passiveminor stress variations state in controlling feeder loads drive powers. “jâ€?offor “activeâ€? stress field j = 0.45 Predicted Performance As anloading aid to the review of the measured test results, a selection relevant predicted performance being filled with iron ore. The bin is of the cycle occurred from5. one test results, of a selection of relevant As an aid presented. toBased the review ofaverage the measured test results, a selection of releva characteristics of the test bin of Figure 3 are The predicted performance is relevant based onperformance 5. Predicted Performance on the fill rate of 35 t/h, ‘Perspex’ construction comprising a five test run to the next, the averagecharacteristics bin predicted performance characteristics ofThe offocus the test binduring of predicted Figure 3loads areoperation presented. bin andof feeder load theories a specific onrelevant gate and feeder as presented in predicted As an established aid to the review the measured test with results, a selection performance of bin fill of height the filling as illustrated in Fi section, variable geometry mass-flow characteristics loadingofrate was approximately 30 to the test bin ofrelevant Figure 3operating are is presented. bin and feeder load theories with a4(b) specific focus on gate and AS3774-1996 flow properties of iron ore and parameters the[4]. testThe binfollowing of Figure 3 established are presented. The predicted performance based on inthe storage capacity while Figure shows theof increase in fe ti [4].onThe flow properties of theinon iron ore and relevan with hopper half-angles a1 = 5.88o, a2 established = 35pilot t/h. This information is required for focus The predicted performance is based the test bin aretheories assumed. bin scale and feeder load withAS3774-1996 a specific gatefollowing and feeder loads as presented impact pressure. the pilot scale assumed. [4]. The following flow properties of the irontest orebin andarerelevant operating parameters of 8.03o and a3 = a4 = a5 = 9.84o. The binAS3774-1996 the determination of the impact loads 3 the pilot scale test bin are assumed. Average bulk density ď ˛ = 2.03 t/m is mounted on three support columns, during the bin-filling operation. Average bulk density ď ˛ = 2.03 t/m3 Wall friction angle ď Śđ?‘¤đ?‘¤ = 25o each of which is mounted on load cells During each test run, the net bin 3 Wall friction angle ď Śđ?‘¤đ?‘¤ = 25o Average density ď ˛ 35 = 2.03 Binbulk fill rate Qm = t/h t/m to enable the bin load to be measured. loads and loads were recorded o Wallgate friction angle ď Ś = 25 Effective angleđ?‘¤đ?‘¤of internal friction ď ¤ =Bin 50o fill rate Qm = 35 t/h o For the measurement of the gate using aBin data logger Effective fillDrop rate height, Qmin= conjunction 35load-out t/h skipwith to filling surface hd =angle 1.0 mof internal friction ď ¤ = 50 o Drop height, load-out skip to filling surface hd = 1.0 m load, a special load cell was developed a laptop computer. loads were Parameter for “activeâ€? Effective angleThe of“jâ€? internal frictionstress ď ¤ = 50field j = 0.45 Parameter “jâ€? for “activeâ€? stress field j = 0.45 Drop height, load-out skip to filling surface h = 1.0 m d comprising a flat plate mounted on recorded from the commencement Based onParameter the average fill completion rate of 35 t/h, relevant performance data has been determined as functions “activeâ€? stress three load transducers that, in turn, of bin loading to“jâ€? thefor of field j = 0.45 Based onillustrated the average fill rate4.ofFigure 35 t/h,4(a) relevant performance of bin fill height during the filling operation as in Figure shows the increasedata has bee were attached to a base plate. AdjustingBasedin the bin-filling The load of binperformance fill during the been filling operation as in Figure 4. Figu storage capacity whileofFigure 4(b) shows theheight increase in time and the corresponding decrease in on the average filloperation. rate 35 t/h, relevant data has determined as illustrated functions in while Figure 4(b) shows theMass increase in time and the screws were incorporated to enable the of bin impact recording continued onoperation for a period of capacity pressure. fill height during the filling as storage illustrated in Figure 4. Bin Figure shows the increase (a) Fill4(a) Volume and (b) c impact pressure. in storage capacity while Figure 4(b) shows the increase in time and the corresponding decrease in clearance the hopper outlet and thereapproximately hours inasorder Bin contents, fill time and impact pre While a gate between will generally be quite “stiffâ€?, is considerable two uncertainty to thetodegree of While a Figure gate 4.will generally be quite “stif pressure. gate surface of to the be set. gate load cell measure the changes bin and gate compressibility bulkThe solid during theimpact bin filling operation. While in thethe “safeâ€?, conservative compressibility of the bulk during The following load cases based on the loadsolid prediction theorytp approach to select a low value of “jâ€?, such as j = 0.1, thedue design willsettlement almost be far unit isiscompletely independent of the loads to the of too theconservative iron

duebin to the high, unrealistic values and of the computedore loads. Thisbin. provided the motivation for the test approach is to select a low value of “j�, suc structure. For the loading load in the (i) Loads During Bin Filling – Active Stress State program that is now described. dueGate to the high, unrealistic values of the c settlement stages of the tests, the bin The final stage of the tests involved The computed results are plotted in Figure 5 which shows

0.400

0.350

9.84o

a2 =

8.03o

0.506

a3 =

o ď Ś 0.350 9.84

ď ł2 = 0.256 8.03o ď Ś

S3

0.506

a3 =

S2

0.333

Fill Height = 1.866

The test bulk solid was dry iron ore. The quantity of ore used for the experiments was 767 kg, the average density following the filling of the bin being 2.03 t/m3. As shown in Figure 3(b), the bin 50 І bulk Australian Bulk Handling Review: January/February 2020 is filled using a rectangular skip containing the iron ore, the skip being hoisted and tipped to the bin loading position using an overhead crane. While some minor variations in the loading cycle occurred

Fill Height = 1.866

0.272

0.333

0.350

0.506

0.350

2.717

0.506

2.717

0.506

0.506

0.272

0.333

Fill Height = 1.866

Fill Height = 1.866

0.350

0.350

0.350

0.400

0.400

programloads thatforisincreasing now described. corresponding fill heights up to the top lev and gate load cell clearance was set at progressively lowering the gate load 4. Pilot Scale Test Bin and Test Procedure 20.23 kg at the HT = 0.272 m level to 85.26 kg at the top leve minimum of approximately in order toshows recordthe the Theatest bin usedclearance for this research is shown in Figurecell 3. Figure 3(a) bindecrease geometrical details 13th Internationa 0.5Figure mm, while making thatupthe gate loadwith as the between while 3(b) shows thesure test set with the bin in being filled ironclearance ore. The bin is of ‘Perspex’ 4. Pilot Scale Test Bin and Test Procedu gate did not make contact the variable bin. the bin mass-flow outlet andwith the gate surface construction comprising a five with section, geometry hopper half-angles Îą1 = The test bin used for this research is shown 5.88Ito,was Îą2 =important 8.03o andthat Îą3 =there Îą4 =was Îą5 =the 9.84o. The bin is mounted three support columns, increased. purpose ofand thisMass final each of (a) The Binon Fill Volume (b) Impact Pressure and Fill Time while Figure 3(b) shows the test(b)set up with which is mounted on load cells to enable the bin load to be measured. For the measurement (a)the Bin Fillpressure Volume versus and Mass Impact Press Figure 4. Bin contents, fill time of and impact fill height. independence of the bin and gate load stage of the test was to observe the construction comprising a five section, var Figure 4. Bin contents, fill time and impact pressure versus gatemeasurements, load, a special load cell was developed comprising a flat plate mounted on three load transducers (a) Bin Fill Volumeinand Mass (b) Impact Pressure and Fill Time while, at the same time, potential decrease gate cell load due o o that, in turn, were attached to a base plate. AdjustingThe screws were load incorporated to enable the clearance 5.88 Îą2 = 8.03 and Îą3 = Îą4 = Îą5 = 9.84 following cases based on load prediction theory,presented inheight. Section 2 are reviewed: Figure 4. Bin contents, fillthe time and impact pressure versus fill simulating a 'stiffly' supporting gate. to the stress field change from active The following load cases based on the load prediction theory presented in between the hopper outlet and gate surface to be set. The gate load cell unit is completely independent which is mounted on load cells to enable t Thestructure. test bulkFor solid dry iron states as a result of the (i)to passive Gate During Filling – Active Stresspresented State, Assumed value j = 0.45 following load Loads cases on the prediction in Section 2 areofreviewed: of the bin thewas loading and loadThe settlement stages of thebased tests, theBin binload and gate loadtheory cell gate load, a special was developed (i) Gate Loads During Bin Filling – load Active Stress State, Assumed v ore. The quantity ore used for the of approximately downward albeit very small, and feeder load theories The computed results are making plotted in Figure 5 which shows the bin vertical pressure oncell the gate and clearance was set at a of minimum clearance 0.5 movement, mm, while sure that the gateestablished The computed results are plotted in Figure 5 which shows the verticalA corresponding loads for increasing fill heights up to the top level of 1.866 m. The loads increase from (i) Gate Loads During Bin Filling – Active Stress State, Assumed value of j = 0.45 that, in turn, were attached to a base plate. was 767 kg,the thebin. average of the ore in the bin. This did experiments not make contact with It was important theiron independence of the binparticular and gate loadwith a specific focus on gate and feeder corresponding loads forvertical increasing fillm. heights upgate to the top level of 1.866 m 20.23 kg at the HT = 0.272 m level to 85.26 kg at the top level HT = 1.866 The computed results are plotted in Figure 5 which shows the pressure on the and measurements, while, at the same time, simulating a “stifflyâ€? supporting gate. bulk density following the filling of the information is of relevance to feeder as presented in AS3774-1996 [4]. between the hopper outlet and gate surface 20.23 at top theloads HT =of 0.272 level 85.26increase kg at the top level HT = 1.866t corresponding loads for increasing fill heights up tokgthe level 1.866mm. Thetoloads from 13th International Conference on Bulk Materials Storage, Handling and Transportation The following flow properties of theloading iron Australia of the bin structure. For the and loa 9-11 July 2019, Queensland, 20.23 kg at the HT = 0.272 m level to 85.26 kg at the top level HT = 1.866 m. 13th International Conference on Bu .250ď Ś .250 ď Ś ore and relevant operating parameters ofclearance o clearance was set at a minimum th 13 International Conference on Bulk Materials Storage, Handling and Transportation Julyassumed. 2019, Queensland, Australia the pilot scale test bin9-11 are did not make contact with the bin. It wa Average bulk density p = 2.03 t/m3 measurements, while, ato the same time, sim Wall friction angle = 25 Bin fill rate Qm = 35 t/h 0.830ď Ś 0.830ď Ś .250ď Ś .250 ď Ś Effective angle of internal friction 0.792 ď Ś 0.792 ď Ś S5 S5 o = 50 a5 = a5 =0.704ď Ś 0.704ď Ś 9.84o 9.84o Drop height, load-out skip to filling surface hd = 1.0 m S4 a4 = a4 = S4 o 9.84 o ď Ś 0.527 Parameter 'j' for 'active' stress field j = 9.84 0.527ď Ś 0.45 0.830ď Ś 0.830ď Ś a3 = S3 Based on the average fill rate of S3 9.84o a3 =o 0.792 ď Ś 0.350 ď Ś 9.84 35 t/h, relevant performance data has 0.792 ď Ś S5 0.350ď Ś a2 = 0.704 5= been determined as a functions of binď Ś 0.704 ď Ś S2 ď ł2 = 8.03o 0.256 o a5 =o S2 9.84 8.03o ď Ś 0.256ď Ś 9.84 fill height during the filling operation a1 = S1 Gate Load Cell as illustrated in Figure 4. Figure 4(a) 5.88o a1 = 0.200ď Ś S1 Gate Load Cell Adjustable S4 5.88o 0.256 ď Ś astorage 4= Adjustable shows the increase in Clearance = o a4capacity 9.84 Clearance o 0.527 ď Ś in while Figure 4(b) shows the9.84 increase 0.527ď Ś (a) Test Bin Arrangement (b) Filling Bin During Test Run time and the corresponding decrease in Figure 3. Pilot scale test bin. 0.350ď Ś


Gate Loads (kg) Gate Loads (kg) Gate Pressures (kPa) Gate Pressures (kPa) 0.5

1.0

2.0

1.5

2.5

Fill Height (m)

0.0 0.0

0.5

1.0

2.0

1.5

Gate Loads (kg) & Pressures (kPa

10.030.0 0.0 20.0 0.0 10.0

Gate Loads (kg) & Pressures (kPa)

Gate Loads (kg) & Pressures ( Gate Loads (kg) & Pressures (kPa)

70.0 90.0 60.0 80.0 50.0 70.0 40.0 60.0 30.0 50.0 20.0 40.0

Gate Loads (kg) & Pressures ( Gate Loads (kg) & Pressures (kPa)

120.0 (iii) 90.0Active/Passive Stress States (Figure 2(c)) j = 0.1 j = 0.45 j = 0.9 (AS3774) 80.0 when 140.0 the stress state switches from “active” to 120.0 The case fully developed “passive” state due to 100.0 j = 0.1 j = 0.45 j = 0.9 (AS3774) 70.0 converging flow inLoads the lower part of the hopper is now considered. Gate (kg) 120.0 100.0 As an example of this, the case of 60.0 80.0 load cushioning was cited in Section 2. For the bin of Figure 3(a), the vertical stress distributions 100.0 50.0 Loads (kg) heights y =0.272 80.0 have been60.0 determined for theGate four switch m, 0.605 m, 1.111 m and 1.615 m. For sw 40.0 Gate Loads (kg) 80.0 60.0 values of the pressure the “active” case j = 0.45 for which the corresponding calculated ratio for the 30.0 40.0 Gateare Pressures (kPa) Gate Loads (kg) four switch stress levels 0.222, 0.285, 0.335 and 0.335. For the “passive” case the values of jf for 60.0 40.0 20.0 Gate Pressures (kPa) 20.0 each 10.0 switch level as determined in accordance with the procedures described in Section 2 are, Gate Pressures (kPa) 40.0 20.0 0.0 respectively, j = 17.123, 13.145, 10.13 and 10.13. The corresponding values for the corresponding f 0.0 Pressures 0 0.5 ratios 0.5 1.0 are 1 kGate 1.5 2(kPa) 1.656 2.5 2.0 1.76, 20.0 0.0 pressure 1.5 = 2.5 “passive” 1.89, and 1.656.0.0 hf

80.0

Parameter j

0

Fill Height (m)

0.0

2.5

0.5

1

1.5

2

2.5

Parameter j Figurepressure. 5. Gate loads asFillfunction Figure 6. Influence of 0 0.5of function 1 1.5“j”-full 2 bin.2.5 the pressure ratio for the four switch Height (m) of fill height. impact Parameterof j fill height. Figure 5. Gate loads as function Figure 6. Influence of function of “j”-full bin. The following load cases based on stress levels are 0.222, 0.285, 0.335 (iii)Figure Active/Passive States 2(c)) 5. Gate loads Stress as function of(Figure fill height. Figure 6. Influence of function of “j”-full bin. the load theory presented (iii) toActive/Passive Stress States state (Figure The caseprediction when the stress state switches in from “active” fully developed “passive” due2(c)) to and 0.335. For the 'passive' case the Theconsidered. case when As theanstress stateofswitches “active” to of fully developed “passive” state due to converging flow in the lower partStates of the(Figure hopper is now example this, the from case of Section reviewed: values jf for each switch level as (iii) 2 are Active/Passive Stress 2(c)) converging flow inthe thevertical lower“passive” part of distributions thestate hopper considered. As an example of this, the case of load Section 2. Forfrom the bin of Figure 3(a),developed stress Thecushioning case whenwas the cited stressinstate switches “active” to fully dueistonow determined in accordance with the load cushioning was cited inmSection 2.the For the bin of Figure 3(a), the vertical stress distributions have been determined forlower the four switch heights isysw =0.272 m, 0.605 m, 1.111 and 1.615 m.case Forof converging flow in the part of the hopper now considered. As an example of this, (i) Gate loads during bin filling – active procedures described in Section 2 are, haveof been determined for thepressure four switch heights theload “active” case jwas = 0.45 forinwhich the 2. corresponding calculated values the ratio for the ysw =0.272 m, 0.605 m, 1.111 m and 1.615 m. For cushioning cited Section For the bin Figure 3(a), theof vertical stress distributions stress state, assumed value =switch 0.45 respectively, jf = 17.123, 13.145, ratio 10.13 and “active” case j = 0.45 for which the corresponding calculated values of the pressure for the four switch levels are 0.222, 0.335 andthe For the “passive” case the values of j for f have beenstress determined for the of fourj0.285, heights y0.335. =0.272 m, 0.605 m, 1.111 m and 1.615 m. For sw four the switch stressvalues levels arethe 0.222, 0.285, 0.335 and 10.13. 0.335.The For the “passive” casevalues the values jf for each switch level as in in accordance with procedures described in Section 2 for are,the The computed results are for plotted corresponding forof the the “active” case j =determined 0.45 which the corresponding calculated of pressure ratio each switch level as determined in accordance with the procedures described in Section 2 are, respectively, j = 17.123, 13.145, 10.13 and 10.13. The corresponding values for the corresponding f four switch stress levels are 0.222, 0.285, 0.335 and 0.335. For the “passive” case the values of j for f Figure 5 which shows the vertical corresponding 'passive' pressure ratios (a) Vertical Stress Distributions (b) Gate Loads Variation with Stress Switch jf = 17.123, 13.145,in10.13 and 10.13. The corresponding values for the corresponding “passive” pressure ratios are khf = 1.89, 1.76, 1.656respectively, and 1.656. each switch level as determined in accordance with the procedures described Section 2 are, Heights pressure on the gate and corresponding =1.89,1.76,1.656and1.656. “passive” pressure ratios are for khf the = 1.89, 1.76, 1.656are andkhf 1.656. respectively, jf = 17.123, 13.145, 10.13 and 10.13. The7.corresponding values corresponding Figure Vertical pressure distributions and gate loads forThe combined active/passive states. loads for increasing fill heights to 1.76, 1.656 computed verticalstress pressure “passive” pressure ratios are khf =up 1.89, and 1.656. the top level of 1.866 m. The loads distributions are As shown in Figure 7(a).the from “ac which under the fully ”active” state is 85 kg as The load computed vertical shown in 7(a). the graphs indicate, which shows shows the the load under thepressure fully distributions ”active” are state isthe 85Figure kg decreasing decreasing as switching switching from “ac increase from 20.23 kg at the HT = As since graphs indicate, the vertical vertical pressure on the hopper outlet decreases rapidly the “arched” or “passive” stress field to “passive” to 5 kg at the switch level y = 0.22 m then approaching, asymptotically, 44 kg sw “passive” totransfers 5 kg the at substantial the switch yswload= to0.22 m then asymptotically, kg aa part level of the bin the hopper walls.approaching, The vertical pressure and potential 0.272 m level to 85.26 kg attothe top pressure on the hopper outlet decreases further increases. gate load reduction due to switching from “active” to “passive” is further illustrated Figure 7(b) further increases. level HT = 1.866 m. rapidly since the 'arched' or in 'passive' stress field transfers the substantial 13 International Conference on Bulk Materials Storage, Handling and Transportation July 2019, Queensland, Australia 6. Test Results (ii) Gate loads, at maximum level part of the bin load to the9-11hopper walls. 6. fill Test Results (i) Initial Filling HT = 1.866m for a range of – The vertical pressure and potential gate (i)j valuesInitial Filling active case reduction due to condition switching from Several the of the from the with (a) Vertical Stress Distributions Gate Loads Variation with Stress Several test test runs runs(b)involving involving the filling filling of Switch the bin bin load from the empty empty condition with iron iron ore ore It is clear that the value of conducted, the load 'active' toLoads 'passive' is presented further illustrated (a) Vertical Stress Distributions (b) Gate Variation with Stress Switch Heights a typical set of recorded bin and gate load results being in Figures 88 aa conducted, a typical set of recorded bin and gate load results being presented in Figures Heights Figure 7. Vertical pressure distributions and gate which loads (b) for combined active/passive stress states. parameter 'j' has a significant influence in85 Figure 7(b) which shows the load (a) Vertical Stress Distributions Gatethe Loads Variation Stress Switch shows load under thewith fully ”active” state is kg decreasing ascondition, switching from “active” Figure 8 illustrates the initial filling of the bin from the empty the filling time Figure 8 illustrates the filling of the bin empty condition, filling time bb 7. Vertical distributions gate from loads forthe combined active/passive stress4the states. Heights to Figure “passive” toinitial 5 kgpressure at the switch level yand then approaching, asymptotically, kg sw = 0.22 m on the gate load determination. This is under the fully 'active' state is 85 kgas ysw approximately 90 Figure 8(a) that the on increases very The computed vertical pressure distributions shown in Figure 7(a).active/passive As the shows graphs indicate, the load Figure 7. Vertical pressure distributions and are gate loadssecs. for combined stress states. further increases. approximately 90 secs. Figure 8(a) shows that the load on the theasgate gate increases very quickly quickly to to ar ar illustrated in Figure 6 hopper which shows the decreasing switching from 'active' The computed vertical pressure distributions are shown in bin Figure 7(a). As theof graphs indicate, the vertical pressure on the outlet decreases rapidly since the “arched” or “passive” stress field 20 kg and then gradually increases to F = 38 kg as the fill level 1.88 m is reached. O G 20 kg and then gradually increases to F = 38 kg as the bin fill level of 1.88 m is reached. O G decrease in loads as the value j to the to 'passive' to 5 kg atorthe switchstress field vertical pressure on the As hopper outlet decreases rapidly since the “arched” “passive” transfers thegate substantial part of the bin of load hopper walls. The vertical pressure and potential The computed vertical pressure distributions are shown in Figure 7(a). the graphs indicate, the 6. Test Results which shows the load under the fully ”active” state is 85 kg decreasing as switching from “active” other hand, the bin load, shown in Figure 8(b) increases gradually at first then, as the fill transfers the substantial part of the bin load to the hopper walls. The vertical pressure and potential gate load reduction due to switching from “active” to “passive” is further illustrated in Figure 7(b) increases. For reference purposes, the part the to hopper now considered. level yswgradually = 0.22 m then other the binof load, in Figure 8(b)field increases at approaching, first then, as the fill hh vertical pressure on the hopper outlethand, decreases since the “arched” or “passive” (i) Initial Filling torapidly “passive” 5shown kg atisthe switch level ystress sw = 0.22 m then approaching, asymptotically, 4 kg as ysw gate load reduction due to switching from “active” to “passive” is further illustrated in Figure 7(b) increases along with the bin volume capacity, the load increases at a faster rate reaching the transfers the substantial part of the bin load to the hopper walls. The vertical pressure and potential Several test runs involving the filling of the bin from the empty condition with iron ore were values of j = 0.1, 0.45 and 0.9 based on along Aswith anincreases. example this, the capacity, case of loadthe load asymptotically, 4 kg ysw further further increases the binofvolume increases at a as faster rate reaching the fu fu 13 International Conference on Bulk Materials Storage, Handling and Transportation gate load reduction due to switching from “active” to “passive” is further illustrated in Figure 7(b) conducted, a typical set of recorded bin and gate load results being presented in Figures 8 and 9. 9-11 July 2019, Queensland, Australia load of F = 730 kg. The total filled load supported by the bin and gate is equal to F = F F AS3774-1996 [4] are also shown. cushioning was cited in Section 2. For increases. TTransportation G + B= 13 International Conference ongate Bulk Materials Storage, Handling and load of FBB = 730 kg. The total filled load supported by the bin and is equal to F = F + F T Australia G B= Figure 8Results illustrates filling the binstate from thekgempty condition, the filling timeQueensland, being 9-11 July 2019, which shows the the loadinitial under the fullyof ”active” is 85 decreasing as switching from “active” 6.the Test of component Figure 3(a), the vertical stress kg. Since the bin load is primarily due to the contact of the bulk solids with the 13bin International Conference on Bulk Materials Storage, Handling and Transportation “passive” 5 kgFigure at theis switch level ythat = due 0.22load mAustralia approaching, asymptotically, 4 kg solids as 90tosecs. 8(a) shows the on the contact gate increases very bulk quickly to yaround swQueensland, sw kg. Since the approximately bin toload component primarily tothen the of the with the bb (i) Initial Filling 9-11 July 2019, (iii) Active/passive stress states (Figure distributions have been determined 6. Test results further increases. 20 kg and then gradually increases to F = 38 kg as the bin fill level of 1.88 m is reached. On the hopper walls, the gate initially carries the major proportion of the load, albeit small, G Several test runs involving the filling of the bin from the empty condition with iron ore were (ii) Gate Loads, at Maximum Fill Level HT = 1.866m for ainitially Range of carries j Values –the Active Case proportion of the load, albeit small, before hopper walls, the gate major before the the for the four switch heights ysw =0.272 (i) Initial filling other hand, the bin load, shown in Figure 8(b) increases gradually at first then, as the fill height conducted, a typical set of recorded bin and gate load results being presented in Figures 8 and 9. It2(c)) is clear that the value of thesupport load parameter “j” has a significant influence on the gate load can begin to take effect. With the bin loaded to the maximum fill height of 1.88m, 6. Test Results support to8 along take effect. With the bin to maximum fill height of 1.88m, the the increases the bin volume capacity, the load increases atruns a faster ratethe reaching the bin Figure illustrates initial filling of theofloaded bin the the empty condition, filling timefull being determination. Thisthe is illustrated in Figure 6can whichbegin shows the decrease inthe gate loads as the value j from The case when stress state switches m, (i) 0.605 m, with 1.111 m and 1.615 m. For Several test involving the filling of Initial Filling load represented as little as 5% of the total load, 95% being carried by the bin or hopper walls. load of F = 730 kg. The total filled load supported by the bin and gate is equal to F = F + F = 768 approximately 90 secs. Figure 8(a) shows that the load on the gate increases very quickly to around Band Tbin G or B increases. For reference purposes, the values of j = 0.1, 0.45 0.9 based on AS3774-1996 [4] are load represented as little as 5% of the total load, 95% being carried by the hopper walls. from 'active' to fully developed 'passive' theSeveral 'active' = 0.45 for the bin from the empty with testcase runsj involving thewhich filling the of the bin from the empty condition withcondition iron ore were kg. Since bin load component istoprimarily due to the the contact ofpresented the with the On bin the or 20 kg andthe then FG = 38gate kg as bin fill level ofbulk 1.88insolids mFigures is reached. also shown. conducted, agradually typical setincreases of recorded bin and load results being 8 and 9. state due to converging flow in the lower hopper corresponding calculated values of major iron ore were conducted, a typical set walls, the gate initially carries the proportion of the load, albeit small, before the wall otherFigure hand, 8the bin load, in Figure gradually at firstthethen, as time the fill height illustrates the shown initial filling of the8(b) bin increases from the empty condition, filling being support can begin to take effect. Withcapacity, the bin loaded the fill very height of 1.88m, increases along with volume increases a faster ratequickly reaching thethe fullgate bin approximately 90 the secs.bin Figure 8(a) shows thatthe the load loadtoon themaximum gateatincreases to around 90.0 load represented little as 5% of theload total 95% being carried byofthe binmor 20 and gradually increases to Fsupported = 38 kg as fill level istohopper reached. On G load, of140.0 FkgB = kg. The total filled bythe thebin bin and gate is1.88 equal FT = FGwalls. + Fthe (AS3774) B = 768 j =730 0.1then j =as 0.45 j = 0.9 80.0 other hand, bin component load, shown is in primarily Figure 8(b)due increases firstbulk then,solids as thewith fill height 120.0the kg. Since bintheload to the gradually contact ofatthe the bin or 70.0 increases withinitially the bin volume theproportion load increases at aload, fasteralbeit rate reaching the full the bin wall hopper walls, along the gate carries capacity, the major of the small, before Gate Loads (kg) 100.0 60.0 loadcan of Fbegin B = 730 kg. The total filled load supported by the bin and gate is equal to FT = FG + FB = 768 support to take effect. With the bin loaded to the maximum fill height of 1.88m, the gate 50.0 80.0 Since the bin load component is primarily due to the contact of the bulk solids with the bin or load kg. represented as little as 5% of the total load, 95% being carried by the bin or hopper walls. th

th

th

hopper walls, the gate initially the major proportion of the load, albeit small, before the wall Gate Loadscarries (kg) 60.0 support can begin to take effect. With the bin loaded to the maximum fill height of 1.88m, the gate load40.0 represented as little as 5% of the total load, 95% being carried by the bin or hopper walls.

40.0

30.0

Gate Pressures (kPa)

20.0

Gate Loads (kg) & Pressures (kPa)

Gate Loads (kg) & Pressures (kPa)

th

10.0

0.0 Level HT = 1.866m of1.0 j Values Case 2.0 0.0for a Range 0.5 1.5 – Active 2.5 arameter “j” has a significant influence Fill Height (m)on the gate load e 6 which shows the decrease in gate loads as the value of j lues of j = 0.1, 0.45 5. and 0.9 loads basedasonfunction AS3774-1996 [4] are Figure Gate of fill height.

Gate Pressures (kPa)

20.0 0.0

0

0.5

1 1.5 Parameter j

2

2.5

Gate Load Figure 6. Influence of function of “j”-full bin. (a)(a) Gate Load

(a) Gate Load

Gate Loads (kg) & Pressures (kPa)

(iii) Active/Passive Stress States (Figure 2(c)) The case when the stress state switches from “active” to fully developed “passive” state due to 140.0 converging part of the hopper is now considered. As an example of this, the case (a)ofGate Load j =flow 0.1 j =in 0.45the j = lower 0.9 (AS3774) 120.0 load cushioning was cited in Section 2. For the bin of Figure 3(a), the vertical stress distributions (a) Gate Load have been 100.0 determined for the four switch heights ysw =0.272 m, 0.605 m, 1.111 m and 1.615 m. For the “active” case j = 0.45 for which the corresponding calculated values of the pressure ratio for the 80.0 four switch stress levels are 0.222, 0.285, 0.335 and 0.335. For the “passive” case the values of jf for Gate Loads (kg) 60.0 each switch level as determined in accordance with the procedures described in Section 2 are, (b) Bin Load respectively, jf = 17.123, 13.145, 10.13 and 10.13. The corresponding values for the corresponding 40.0 “passive” pressure ratios Gate are Pressures khf = 1.89, 1.76, 1.656 and 1.656. (kPa) 20.0 Figure 8. Bin and gate loads during filling – iron ore. 2.5

eight.

0.0

0

0.5

1 1.5 Parameter j

2

2.5

Figure 6. Influence of function of “j”-full bin.

gure 2(c)) from “active” to fully developed “passive” state due to hopper is now considered. As an example of this, the case of For the bin of Figure 3(a), the vertical stress (ii) Load (ii)distributions Load h heights ysw =0.272 m, 0.605 m, 1.111 m and 1.615 m. For

(b) Load Bin Load (b)Bin Bin Load (b)(b) Bin Load (ii) Load Settlement In order to investigate the influence ofand load settlement withfilling undisturbed storage time, the recording Figure 8.8.Bin gate loads during filling iron ore. Figure Bin and gate loads during – –iron ore. 8. Bin loads during –– iron of the bin andFigure gate loads a period of, nominally, 2 hours following the completion of Figure 8.continued Bin and andforgate gate loads during filling filling iron ore. ore. the filling operation. As shown in Figure 9, this resulted in a decrease of 8 kg in the gate load and a Load Settlement corresponding increase of 8 kg in the hopper wall support load as indicated in Figure 9. This indicates (ii) (ii)Load Settlement In order to investigate influence loadAustralian settlement with undisturbed storage time, theasrecording Bulk Handling Review: January/February 51 the effect load transfer toinfluence the hopper walls due to the downward converging creep the2020 ironІ ore In order toofinvestigate thethe ofofload settlement with undisturbed storage time, the recording of the bin and gate loads continued for a period of, nominally, 2 hours following the completion of Settlement approaches its critical consolidation condition. It also highlights the transitional phase of the changes of the bin and gate loads continued for a period of, nominally, 2 hours following the completion of Settlement the filling operation. As shown in Figure 9, this resulted in a decrease of 8 kg in the gate load and a the filling operation. As shown in Figure 9, this resulted in a decrease of 8 kg in the gate load and a


TECHNICAL PAPER

Figure 9. Bin and gate loads during static storage – iron ore. (iii) The “j” Parameter For the measured value of FG = 38 kg, reference to Figure 6 shows that the corresponding value of “j” = 1.8 which is significantly higher than the values of “j” recommended in AS3774-1996 [4] as indicated in Table 1 below.

of recorded bin and gate load results Table 1. Gate Load Prediction in Accordance with AS3774 – 1996 [4] being presented in Figures 8 and 9. Parameter - j Gate Pressure (kPa) Gate Load (kg) Method Figure 8 illustrates the initial filling 0.1 34.457 110.345 AS3774 – 0.45 26.622 82.255 of the bin from the empty condition, 1996 0.9 19.698 64.081 the filling time being approximately 1.8 11.866 38 Measured 90 secs. Figure 8(a) shows that the load on the gate increases very quickly In the case of the testgate bin,loads the value j = 1.8for maya be regarded as, a “global” value onbin, the “active” to around 20 kg and then gradually and continued period In the case of based the test the value j stress state theory. More than likely, the stress field is a combination of “active” and “passive” as increases to FG = 38 kg as the bin fill of, nominally, two hours following the = 1.8 may be regarded as, a 'global' value described in Section 5 (iii). level of 1.88 m is reached. On the other completion of the filling operation. As based on the 'active' stress state theory. hand, the bin load, shown in Figure shown in Figure 9, this resulted in a More than likely, the stress field is a (iv) 8(b) Transition Considerations increases gradually at first then, the decrease the gatetoload and a change combination of 'active' as Theasimportant influenceofof8 kg thein“active” “passive” in the stress field inand the 'passive' hopper in fill height increases along withcontrolling the bin the corresponding increase ofin8 Figure kg in the described 5 (iii). gate load is demonstrated 10. The graph shows in theSection variation of the gate load volume capacity, the load increases at hopper wall support load as indicated a faster rate reaching the full bin load in Figure 9. This indicates the effect 13th International (iv) Transition considerations Conference on Bulk Materials Storage, Handling and Transportation 9-11 July 2019, Queensland, Australia of FB = 730 kg. The total filled load of load transfer to the hopper walls The important influence of the 'active' supported by the bin and gate is equal due to the downward converging to 'passive' change in the stress field to FT = FG + FB = 768 kg. Since the bin creep as the iron ore approaches its in the hopper in controlling the gate load component is primarily due to the critical consolidation condition. It also load is demonstrated in Figure 10. The contact of the bulk solids with the bin highlights the transitional phase of graph shows the variation of the gate or hopper walls, the gate initially carries the changes in the stress fields from load as a ratio of the total bin load the major proportion of the load, albeit 'active' to 'passive'. The results of this from the commencement of the filling small, before the wall support can begin phase of the gate load measurement operation. For the first 8 seconds the to take effect. With the bin loaded to indicate the influence of the degree of gate carries 100 per cent of the loaded the maximum fill height of 1.88m, the compressibility of the iron ore. iron ore without bin or hopper wall gate load represented as little as 5 per support. The stress field is deemed cent of the total load, 95 per cent being (iii) The 'j' parameter to be 'active'. During the next four carried by the bin or hopper walls. For the measured value of FG = 38 kg, seconds, as the load transfer to the reference to Figure 6 shows that the bin walls commences, the gate load (ii) Load settlement corresponding value of 'j' = 1.8 which is decreases rapidly to 30 per cent as In order to investigate the influence significantly higher than the values of shown. This is due to the transition to of load settlement with undisturbed 'j' recommended in AS3774-1996 [4] as the 'passive' stress state. Then for the in the stress fields from “active” to “passive”. The results of this phase of the gate load measurement storagethe time, the recording of the bin indicated in Table remainder of the filling operation, as indicate influence of the degree of compressibility of the iron ore. 1 below. the transition to the fully developed 'passive' stress state continues, the gate load further decreases approaching, asymptotically, the value of 5 per cent of the total bin load. For the pilot scale bin of Figure 3, the stress switch commences after approximately 12 seconds from the commencement of filling. This corresponds to the fill level of 0.7 m which is approximately 0.1 m above the (a) Gate Load bottom level of the hopper of Section S3 of Figure 3. This clearly demonstrates (b) Bin Load the importance of the 'passive' stress field in controlling the gate load as discussed in Sections 2 and 5(iii). In effect, the natural consolidation due to load settlement of the iron ore in the lower hopper sections of the bin and the associated 'passive' or 'arched' stress field state is sufficient to support the major proportion of the total stored load in the bin without any further increase Figure 9. Bin and gate loads during static storage – iron ore. in the gate load.

(iii) The “j” Parameter For the measured value of FG = 38 kg, reference to Figure 6 shows that the corresponding value of 52 =І 1.8 Australian Handling Review: 2020 “j” which Bulk is significantly higherJanuary/February than the values of “j” recommended in AS3774-1996 [4] as indicated in Table 1 below.


the total bin load. For the pilot scale bin of Figure 3, the stress switch commences after approximately 12 seconds from the commencement of filling. This corresponds to the fill level of 0.7 m which is approximately 0.1m above the bottom level of the hopper of Section S3 of Figure 3. This clearly demonstrates the importance of the “passive” stress field in controlling the gate load as discussed in Sections 2 and 5(iii). In effect, the natural consolidation due to load settlement of the iron ore in the lower hopper sections of the bin and the associated “passive” or “arched” stress field state is sufficient to support the major proportion of the total stored load in the bin without any further increase in the gate load.

Conclusions

Figure 10. Bin and gate load ratio during filling. (v) Influence of Gate Clearance In the test program, following the nominal 2 hour load settlement period, the gate was progressively lowered to increase the clearance between the bottomthe of the hopper outlet and the gate. The measured (v) Influence of gate clearance hopper opening dimension of 200 gate loads for three separate tests are plotted in Figure 11. As shown the gate loads decrease quickly Inthe theclearance test program, the 0 to 4 mm, mm corresponds to a gateasymptotically load of 5 kg the as increasesfollowing over the range after that load approaches nominal loadfurther settlement or 13.2 per cent of measured initialwith gatethe value 5 kg two-hour as the clearance increases. It is interesting to compare the results plotted predictions presented in progressively Figure 7(b) where the “active” and38“passive” stress state combination is period, the gate was load of kg. considered. is, when theclearance switch level ysw is such that the “passive” stress state is fully developed lowered toThat increase the in the hopper. It is noted that the measured value of the gate load FG = 5 kg is very close to the between the bottom of the hopper (vi) Cohesive strength considerations predicted value of FG = 4 kg. outlet and the gate. The measured

An aspect of mass-flow bin design

gate loads for three concerns the possible impact onstiffness the These test results are an separate indication tests of the are inferred significant influence of decreasing gate on the reduction in gate loads. this case a clearance ofgate 5 mmload or 2.5% of the hopperof opening dimension plotted in Figure 11. As In shown, the determination the cohesive of 200 mm corresponds to a gate load of 5 kg or 13.2% of measured initial gate load of 38 kg. gate loads decrease quickly as the clearance increases over the range 0 to 4 mm, after that load approaches asymptotically the value 5 kg as the clearance further increases. It is interesting to compare the results plotted with the predictions presented in Figure 7(b) where the 'active' and 'passive' stress state combination is considered. That is, when the switch level ysw is such that the 'passive' stress state is fully developed in the hopper. It is noted that the measured value of the gate load FG = 5 kg is very close to the predicted value of FG = 4 kg. These test results are an indication of the inferred significant influence of decreasing gate stiffness on the reduction in gate loads. In this case a clearance of 5 mm or 2.5 per cent of

Test 1 Test 2 Test 3 30 20 10 0

0

2

4

Authors: Alan Roberts1,2, Brendan Beh1, Jiahe Shen2, Bin Chen1, and Timothy Donohue1 1TUNRA Bulk Solids, The University of Newcastle 2Centre for Bulk Solids and Particulate Technologies, The University of Newcastle

strength of the bulk solid which is the basis of determining the critical References hopper outlet dimension, BCR. When 1. [1] McLean, A. and Arnold, P., 1979. the actual opening dimension B > A Simplified Approach for the BCR, discharge flow can occur. Also, Evaluation of Feeder Loads for loads can be transferred to the gate. 13th International Conference on Bulk Materials Storage, Handling and Transportation Mass-Flow Bins. J. Powder Bulk But when B ≤ BCR, a stable arch will 9-11 July 2019, Queensland, Australia Solids Technol. 3, pp. 25–28. form over the outlet without load 2. [2] Roberts, A. W., Ooms, M. and transfer to the gate and without the Manjunath, K. S., 1984. Feeder possibility for discharge flow. This is Load and Power Requirements in a plausible explanation as to why the the Controlled Gravity Flow of Bulk measured gate loads in the pilot scale Solids from Mass-Flow Bins. Trans. tests are lower than those that were I.E. Aust., Mechanical Engineering, predicted. However, it is an aspect of Vol. ME9. No.1, pp. 49-61. gate load determination that warrants 3. [3] Roberts, A.W., 2001. An further investigation. By way of Overview of Feeder Design background, the study of stable arch Focusing on Belt and Apron formation in wedge-shaped, planeFeeders. Bulk Solids Handling, Vol. flow hoppers handling iron ore was 21, No. 1, pp. 13-24. performed by Guo [5]. Also, the work 4. [4] AS3774-1996, Loads on Bulk of Roberts [6] is of relevance.

50 40

This paper has raised a number of important aspects of gate load determination as well as, in the wider sense, the fundamental properties of bulk solids relating the consolidation behaviour to the stress fields under storage and flow. These matters are the subject of ongoing research. • This article was originally published in the 13th International Conference on Bulk Materials Storage, Handling and Transportation ICBMH 2019 Proceedings. Permission has been given to ABHR to republish

6

8

Gate Clearance (mm)

10

12

Figure 11. Measured reduction in gate loads as a function of gate clearance.

Solids Containers. Standards Association of Australia. 5. [5] Guo, J., 2014. Investigation of Arching Behaviour Under Surcharge Pressure in Mass-Flow Bins and Stress States at Hopper/ Feeder Interface. PhD Thesis, The University of Newcastle, Australia. 6. [6] Roberts, A. W., 2010. Review of Mass-Flow Hopper Design with Respect to Stress Fields and Surcharge Loads. Particuology Vol. 8, No. 6, pp. 591–594.

(vi) Cohesive Strength Considerations An aspect of mass-flow bin design concerns the possible impact on the gate load determination of the Australian Bulk Handling Review: January/February 2020 І 53 cohesive strength of the bulk solid which is the basis of determining the critical hopper outlet dimension, BCR. When the actual opening dimension B > BCR discharge flow can occur. Also loads


CONVEYORS

talk

Choosing the right belt – Part 1 STEVE DAVIS In his regular BULKtalk column, Steve Davis considers the basics of bulk handling that sites often struggle with. He shares his insights gained from more than 30 years in bulk materials handling. Steve has worked in bulk handling for 30 years, for both resource companies and professional engineering firms, in Australia, South Africa, the Middle East and Canada. His experience encompasses such commodities as iron ore, coal, potash, phosphates, petcoke, sulphur, sands and grain.

Steve Davis, senior bulk handling expert at Advisian, explains the ins and outs of buying the right conveyor belt and how choosing the wrong one can cost millions. THE CONVEYOR BELT IS A SIGNIFICANT component of the capital and operating cost of a conveyor. We should be looking for the best possible life from the belt and its splices, and taking every opportunity to minimise damage and wear, while meeting target throughput. A belt that is volumetrically undersized for the duty will result in not meeting nameplate or produce spillage, both of which are ongoing losses to the operation, and costs in clean up and collateral damage. Many belts are designed around optimistic surcharge angles and reduced edge clearances or operated over original design parameters. Poor loading onto belts leads to accelerated wear, carcass damage, belt tracking and reduced life. At $200 per metre, a 20-kilometre conveyor (40-kilometre belting) is an investment of $8 million. For iron ore, the current value is currently about $80 per tonne and for a 5000 tonnes per hour conveyor, each hour lost is an opportunity cost of $400,000. The cost for an unplanned change-out of one reel of belt, assuming the belt is available, for two days, including labour and lost opportunity, would exceed $25 million.

What life to expect? Belt life expectancy should be several years and perhaps more than 10 years before fatigue failure. Often in the mining industry, we see shorter lives. Three failure modes are common to all belts, cover wear, fatigue and overstress, and damage. Cover wear is less of an issue when conveying low abrasive ores. Cover thickness, good load chute design with attention to loading speed and direction will result in good belt life. Abrasive ores such as iron ore can cause one millimetre per month wear on short cycle conveyors. A three-year cover life for longer conveyors is good. Focus should be on load chute and skirt designs that minimise wear at the load point, and cover material and thickness that gives maximum practical life.

54 | Australian Bulk Handling Review: January/February 2020

Well loaded belt, tracking centrally, some wear lines obvious and what surcharge angle would be correct?

The change in belt section from wear changes the tension distribution when wrapped around pullies. The selection of conveyor belting must be justified through comparative testing by TUNRA or similar, or some industry benchmarking to obtain the best cover material and longest life. Testing and experience indicate a wide range of wear rates between nominally similar compounds from respected suppliers, and for different ores. Particle size (coarse, lump, fine), moisture content, drop height, type of impact bed, belt speed and chute design all influence cover wear. Fatigue failure is the result of many cycles of bending and stressing and occurs in covers and in the belt carcass. A conveyor that is well designed, installed and operated should see even fatigue across the width of the belt. Poor design of transitions and turn overs, curves, tripper and


Section through belt showing wear profile. Outer cords carry more tension around a “dirty side” pulley.

shuttle approaches are common causes of tension and fatigue bias across belt width. Build-up of ore on pullies and significant cover wear can result in localised high stresses in the belt that lead to early fatigue, typically on the edges or in the centre. Fatigue results in cover compound cracking, splice failure initiation, and carcass damage such as broken wires. Misalignments and overtensioning can also bias tensions across the belt. If part of the width has failed, even in one location, the strength of the belt has been reduced, and progressive failure is probable. If not monitored, this can lead to unexpected belt failure. Design of the conveyor should consider the minimum possible number of pulleys, minimum allowable diameters, correct pulley spacing to reduce reverse bending (the one second rule), and correct design of transitions and curves. Operations should consider the result of any action that changes the tensions and transitions. Damage can result from many sources, and most can be anticipated. •U  ltraviolet (UV) cover damage seen as cracking and spalling. This can be reduced by covering belts and UVresistant covers. •C  hemical and heat damage can be reduced by selecting the correct cover compound. Some dry fine materials such as cement and alumina, not normally considered chemicals, attack some cover compounds

and cause cracking. •E  dge damage from tracking into structures and equipment can be reduced by installing belt drift monitors and aligning the conveyor. •D  amage from carry back and spillage build up on pulleys and idlers can be reduced by sizing the belt for the maximum throughput and installing quality belt cleaning and spill protection devices. •W  ind can turn the conveyor belt over or push it into structures resulting in spillage and damage. Wind barriers will prevent this. •D  amage to and from pulley lagging can be reduced by having correct lagging, minimising spillage, installing pulley cleaners, shedders and belt ploughs to keep spillage from entrapment between the pulley and belt. •D  amage from tramp metal is less easy to prevent but damage can be minimised by removal of tramp using an over belt magnet and by metal and rip detector systems at critical locations. •G  roove damage from a dragging belt skirt that removes cover rubber directly or by ore entrapment should be designed out. • I dlers that fail into ‘cookie cutters’ and ‘potato peelers’ should not be used, and quality idler seals and bearing arrangements are preferred. Identify and change seized

idlers before damage results. •L  imit belt damage by installing and maintaining quality cleaners and ploughs. Splice interface with cleaners and ploughs should minimise risk of ‘digging in’ under the front edge of the splice. The above list is not exhaustive. Providing well designed and properly installed components with good access to maintain will not add much to the cost of a conveyor. The life of the belt will benefit, and most of the components will last longer. Plant safety will be better. A 20-kilometre belt will have approximately 75,000 idler rolls. Even if a cheaper roll is $20 less than a better-quality roll, does the potential $1.5 million saving balance out the $25 million potential loss from a small rip, not to mention the greater number of roll failures?

Belt strength selection Computer design programs help select belts using user defined inputs like minimum bulk density, surcharge angle, edge clearance, design tonnage, belt speed and belt safety factor. They then define an acceptable belt strength based on the inputs and other components to suit. It is relatively easy to iterate the calculations and check options. Absolutes used in conveyor specifications should be viewed with care. For example, specifying a maximum speed of six metres per

Australian Bulk Handling Review: January/February 2020 | 55


CONVEYORS

Cover crack on belt edge, likely from cord failure dur to pulley build up or poor transition tensions.

second may result in a wider or higher strength belt than 6.4 metres per second. There is no practical difference between these two speeds. Be flexible. There are several load factors in use, nominal and design and other values for capacity are used. Interpretation varies, but it is vital the designer understands user expectations. Assuming a surcharge angle from a text often results in incorrect belt selection as, for various reasons, loading does not produce this angle. Low, zero, and even negative surcharges are common in practice, due to ore variation and chute configuration. Surcharge angle can reduce along long conveyors reducing edge clearance. Conveyor loading is rarely a steady state, as in belt design, and therefore an allowance for surging is appropriate. Feed from an apron feeder or bucket wheel can result in 25 per cent surging. Ore properties can be extremely variable. The best source of data is from a site visit to a similar conveyor. Safety factors allow for

inefficiencies in splicing, and account for many variables in the life of the belt, especially in the field where conditions are rarely ideal. The safety factor derates the nominal strength of the belt carcass to allow for these variables. Safety factors were first stated in DIN 22 101, 1982, and there is considerable discussion around what to use in each application. 1. For fabric belts, belt safety factor is often a nominal 10:1. Little testing of fabric splices has been completed thus far. Many fabric belts have higher design safety factors if operating conditions are considered poor. If clip splices are used, consult the supplier. 2. Steel cord safety factors were a nominal 6.7:1, but advances in splice design and laboratory testing have led to consideration of lower factors, down to 4:1 or lower. There are several splice test facilities, so for a long or expensive belt it is worth testing the splice to confirm efficiency. Lower factors are acceptable and reduce belt strength requirement and cost, however

56 | Australian Bulk Handling Review: January/February 2020

splice quality in the field must be good quality, and other aspects of belt change during life should be considered. 3. Increasing the tonnage throughput on the conveyor reduces the safety factor when based on using ‘spare’ power and capacity. If it is likely this will occur, design initially with a margin or be prepared to change speeds and power. 4. Using smaller than recommended diameter pulleys or locating reverse bending pulleys too close, or any of the issues in the previous section, increase splice fatigue rate and further reduce the safety factor. 5. For longer life belts, the strength of carcass and splice will diminish with time. 6. Changing the belt source at a belt change-out could result in a different splice efficiency. 7. For conveyors with high dynamic belt tensions from stopping and starting, generally overland, the selection of take up type and other factors change belt tension requirements. Each conveyor is different, as is each design team, so different solutions are possible. There is no single correct design or selection. I recommend clear user definition of expectations and minimum design inputs, and that the final design be re-evaluated when all details are firm. Due to differences in interpretation, I recommend an independent check of complex conveyor design at this stage.

The other parts of the belt Having considered all the above, we now have belt speed, width and strength for the carcass of the belt. This is based on agreed design inputs. There is no global standardisation on the make-up of the carcasses, so there may be several combinations of steel cord diameter and spacing that make up a particular strength. Fabric carcasses have more potential variations that achieve the same strength. Selection may be dictated by standardisation, otherwise allow suppliers some flexibility in proposals. We have to select the compound for covers. There are many cover


compounds available, and each manufacturer has their own proprietary mixes. Select covers that meet requirements. Options include low rolling resistance for bottom covers, gouge or abrasion resistant top covers, special covers for temperature or for alumina and cement, oil and chemical resistance colour and food grade. Grade M or N and other generics may be appropriate, but is it best for life costing? Are all similar grade covers the same? As noted earlier these compounds can be compared at a test facility. Cover thickness is a trade-off of cost versus wear rate. Thicker covers may give a longer life but consider pulley diameters and belt cost. Most belt suppliers will provide guidance on selection of their belts. Most can meet the detailed manufacturing quality requirements of regional standards. Australian Standards require QC testing; do you need other tests?

ensure compliance. All hot or cold splices require a splice kit. These contain glue and filler pieces, which are specific to the belt. Use of incorrect kits may reduce splice life. These kits have a shelf life and storage requirements, usually cool or cold. Once past expiry date they should not be used. Incorrect splice kit transport to site or cooler failure will affect splice quality. Some suppliers will confirm suitability of splice kits, which is beneficial for replacement of critical belt splices.

results from two pieces of belt being longitudinally spliced together in the factory. The current maximum belt width is 3.2 metres, any wider requires a joined belt. I would not use these in a critical application. Steel cord belts are generally made in the specified width with sealed edges. Fabric belts can be requested with or without sealed edges. Sealed edges protect the carcass from chemical or moisture ingress. Split belts always have one edge that is not sealed. Observation

Steel cords exposed due to cover wear and/ or build up on a dirty or damaged pulley.

Splices Whether steel cord or fabric, all belts must be spliced to form an endless loop. The splice is the weak point in the belt and is the main reason we have a safety factor. Vulcanised splices rely on the spliced cover and filler compounds to carry belt tension in shear. There is no direct joining of the carcass materials. Splices require good design, and the quality of the equipment and process to make them in the field. Good conditions give best quality, so include splice facilities in the conveyor design. Steel cord belts must be hot spliced. Fabric belts have the option of hot or cold splicing and ‘clipping’. Hot splices must be between two pieces of belt with the same cord or carcass configuration and cover compounds. Cold splices for smaller belts may be able to join two similar pieces of belt. Belt clips are available in many different formats, and guidance from vendors is recommended. A detailed record of all splices should be maintained. If site conditions are dirty, dusty or cramped, or if quality splices can’t be guaranteed, increase the belt safety factor to compensate. Obtain a splice design from the belt supplier and

Splits, joints and edge sealing Split belts, mostly fabric carcass, are available from many suppliers. Suppliers carry stock of a wide belt and slit it to width. This is useful in an emergency, but there are some risks in making sure the belt is compatible in a repair, and in some cases a resulting belt drift problem. Tracking is due to unbalanced tensions from splitting a symmetrical fabrication and generally cannot be fixed. Centre splits are better than edge splits as the tensions are likely to be more balanced. For fabric belts, clipping instead of splicing will avoid cover incompatibility. Split steel cord is rare, but I have seen different width belts with similar specification spliced for emergency repair. Centre joints are when a wider than available belt is required, and

indicates that open edge fabric belts can start fraying after some time in service. Sealed edges do not protect against contact with structure but are better than unsealed.

Specifications If the specification used to purchase belt and splice kits is not clear and detailed, there is a considerable risk of misinterpretation and incorrect supply. As belts are mostly made to specification, it can include valuable information such as the lead time for supply. Avoid being forced into using incompatible belts. A marked change in belt cover, cord or splice life after a repair can indicate that an incompatible belt was procured. Mechanical damage is generally independent of belt specification.

Australian Bulk Handling Review: January/February 2020 | 57


MEMBER PROFILE

I have been a member of ASBSH since…

MEMBER PROFILE:

Priscilla Freire In each issue, ABHR profiles a member of the Australian Society for Bulk Solids Handling (ASBSH). We speak to Priscilla Freire, Business Development Engineer for TUNRA Bulk Solids and Research Development Engineer for the Centre for Bulk Solids & Particulate Technologies.

September 2019. I decided to join the Society after attending the very successful International Conference on Bulk Materials Storage, Handling & Transportation at the Gold Coast and wanted to be more involved with other events that promote the development of engineers and researchers.

bulk solids handling sector, coordinating projects and attending and organising technical events. There is never a dull moment.

In my role it’s important to... stay up to date with new projects under development, new companies and ‘who-is-who’ in the world of materials handling.

I joined the ASBSH...

The project I am most proud of is...

to provide my support to the Society and to expand my network in the field of bulk solids handling in Australia. Coming from Brazil, I am fairly new in Australia, and being a part of a society allows me to gain better understanding of the Australian bulk handling market.

coordinating the set-up of a research laboratory at the University of São Paulo in Brazil through the collaboration between the bulk solids handling group at the University of Newcastle and the Mining and Petroleum Engineering Department at USP.

I got into bulk handling...

My career highlight is...

after seeing how passionate my father is about the wonderful world of mining and materials handling. I had the great privilege to start my career working literally side-by-side with him at Ausenco in Brazil and came into contact with massive projects from early conceptual design to engineering, procurement, construction management. Seeing how passionate he is about all things bulk-handling and conveying sparked my interest.

receiving a letter of recommendation from the Head of R&D – Mining in thyssenkrupp (Brazil) for ‘contributing to the development of Brazilian technology’ through ‘enabling knowledge transfer to Brazilian engineers in all the production chain’.

I am currently researching… the economics behind bulk handling systems (more specifically transfer chutes). One of the questions engineers in this field are often asked is “why should I invest in characterising materials before starting my project?” or “what is the economic benefit of investing in advanced engineering practices and laboratory testing?”. I am currently doing a PhD with the Centre for Bulk Solids & Particulate Technologies at the University of Newcastle hoping to answer some of these questions.

I love my current work because... it is very dynamic. My work involves interacting with clients, researchers, engineers and technicians, chasing up funding sources for research projects, promoting education activities in the

58 І Australian Bulk Handling Review: January/February 2020

I am inspired by... my parents. Being raised by very hardworking people that value education above all has opened all doors for the development of my career in a supportive environment (especially in a field where there still is so little female representation).

The most valuable lesson I have learned is… each individual skillset is valuable and has its space. Working alongside knowledgeable engineers, technicians and academics, but also with highly experienced communications specialists, allows for the exchange of knowledge but also the development of soft skills.

My plans for the future are… finishing my PhD and taking on a fulltime position as business and research development engineer in the field of bulk solids handling, bringing solutions to difficult challenges by closing the gap between specialists and industry.


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