Modern Quarrying Q1 2019

QUARTER 1 – 2019

USHERING IN AN INDUSTRY FIRST

CONTENTS In a ground-breaking development, Metso and its southern African distributor, Pilot Crushtec International, have rolled out an industry first, standard 5-year/10 000-hour warranty on all Metso crushers and screens.

QUARTER 1 – 2019

BLASTING

CRUSHING

ON THE COVER

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16

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TURNING CHALLENGES INTO STEPPING STONES PAGE 26

ALL-IN-ONE WET PROCESSING TECH FOR SOUTHERN AFRICA PAGE 34

AROUND THE INDUSTRY 04 Cement imports on the rise in SA - Industry Insight 05 Aspasa invited to give input into the Mining Charter 06 Q3 ACI shows further improvement in sector activity SUPPLY CHAIN 38 Cat 990K Aggregate Handler boosts wheel loader production 39 Pilot Modular products take Metso to heart

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SCANIA’S TOTAL SOLUTIONS FOR QUARRIES When making buying decisions, quarries need to evaluate everything that surrounds the product – from financing and insurance through to maintenance programmes. With its total solutions approach, Scania South Africa has every parameter covered.

MAXIMISING LOAD/ HAUL PRODUCTIVITY The productivity of any surface mine largely hinges on the efficiency of its load and haul system. Yet, loading and hauling run of mine material represents a very significant component of the total oper- ating cost. Consequently, the incentive to reduce cost in this area remains high.

CIRCULATION Karen Smith PUBLISHER Karen Grant

EDITOR Munesu Shoko quarrying@crown.co.za ADVERTISING Bennie Venter benniev@crown.co.za DESIGN Ano Shumba

DEPUTY PUBLISHER Wilhelm du Plessis

PRINTED BY: Tandym Print

PUBLISHED QUARTERLY BY: Crown Publications P O Box 140 Bedfordview, 2008 Tel: +27 11 622 4770 Fax: +27 11 615 6108 www.crown.co.za

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TOTAL CIRCULATION 2 465

The views expressed in this publication are not necessarily those of the editor or the publisher.

EFFICIENCY MATTERS

T he current business climate in the aggregates industry is characterised by price volatility, shrinking margins and increasing operational costs, among several other challenges that relate to legislative requirements. This is exacerbated by a steady decline in the growth of aggregates demand due to the lack of meaningful construction projects. In a difficult 2018, the construction sector endured a tough cycle, and one of the respected figures in the industry tells me that volumes of construction materials sold during last year shrunk by up to 15% in certain markets. This has placed certain aggregates suppliers under immense pressure, especially those with weaker balance sheets. In 2019, volumes are expected to remain at the lower levels of 2018 and this could lead to distress of certain players. To survive and mine profitably during such a low growth cycle, quarry owners need to capitalise on the opportunity to improve their productivity and focus on one factor they can control: operational efficiency. As you will see in this edition’s Blasting, Load and Haul, Crushing and Wet Processing features, a key takeaway is that operational efficiency is a parameter of vital importance. Increasing productivity is one of the key drivers to counter diminishing

equation is estimated to be between 25-30% based on the whole operation cost, including site personnel and vehicle costs. So, how can quarry owners reduce their operation’s unit cost related to load and haul? A reduction in the unit cost of loading and hauling can been achieved, on one hand, by applying new and innovative mining equipment and methods, and on the other hand, by optimising the use of existing equipment. To run a successful load and haul fleet optimisation programme, it is important to ensure that the machinery is correctly matched to the site and application, as well as the timing of cycles compared to the number of trucks. While washing increases the value of aggregates, it is also a water- intensive process. Considerable water is lost to evaporation and incorporation into the product. Employing water efficiency practices reduces water loss and saves money. Recycling aggregate wash water can save large quantities of water. Most aggregate producers still use conventional settling ponds or tanks, but these have proved to be enemies of efficiency. As you will see in this edition’s Wet Processing feature, new technology, such as CDE’s Combo all-in-one wet processing and water recycling plant, offers a practical solution to these concerns. All six processing stages of the CDE Combo plant have been designed with low energy consumption in mind, while operators also benefit from economical water consumption, with an incorporated water management unit that recycles up to 90% of used water directly into the system. A key talking point here is that primitive and unplanned work, not using technology in a rational way and ignoring research and development findings can all negatively affect producers’ operational efficiency. It is also important to note that operating efficiency will not be achieved by focusing on a single operational process, but paying attention to the whole production value chain.

profit margins as it effectively reduces operating costs. However, the emphasis should not only be on increasing output with the same input, but increasing the output while decreasing the input, and ultimately adding optimum value to current resources. Research shows that an increase in production will ultimately decrease the operation’s unit cost, especially fixed costs. One parameter that has a significant effect on unit costs in quarries is the cost of drilling and blasting. Blasting is one of the most important operations, and has substantial technical and economic effect on any mining project. The prime aim of blasting is rock fragmentation that is necessary for subsequent processes – such as load and haul, crushing and screening – to achieve higher efficiency. Therefore, good blast design and execution are essential for successful quarry operations. Improper or poor practices in blasting can have a severely ill impact on the economics of an operation. Load and haul is probably the biggest cost driver for any quarry. Yet, if properly implemented, a load and haul optimisation programme can identify significant opportunities for operational improvement. As you will see in the Load and Haul feature in this edition, the cost percentage of this process in the whole production

COMMENT

Munesu Shoko – Editor quarrying@crown.co.za

@MunesuShoko

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MODERN QUARRYING QUARTER 1 - 2019

INDUSTRY NEWS

Cement imports on the rise in SA – Industry Insight

Imports of cement into South Africa increased by 166,4% and 144,1% year-on-year during the months of September and October 2018, totalling 131 914 tons (t) (September) and 115 151 t (October), mainly from Vietnam and Pakistan. Nothing has been reported from China, since June 2018. This is according to sta- tistics from Industry Insight, a provider of primary management information services to stakeholders in the South African construc- tion industry. The total tons imported for the first 10 months reached 849 781 t, representing an increase of 104,7% year-on-year, compared with the same period in 2017. This means there were 434 673 t more imported in 2018 compared with 2017. The cur- rency on average, appreciated by around 2% in the first 10 months of 2018, averaging R13,06/US dollar, versus an average of R13,26/ US dollar in the first 10 months of 2017, which may have been a contributing factor to some degree supporting higher growth in imports, but seems too mild to be the main driver. The main driver therefore is the new entry into South Africa which is Vietnam, which started exporting to South Africa from March 2018, averaging close to 50 000 t per month. In total, Vietnamese cement exports (not just into South Africa) increased by 55% in the first seven months of 2018, totalling 17,8 million tons, against a target of between 18 and 19 million tons.

South African cement exports were slightly up (by between 3 and 4%) in September and October compared with the same two months in 2017, with the bulk exported to neigh- bours Botswana and Swaziland. During the 10-month period, South Africa exported around 630 705 t (a decrease of 2%). Imports are currently exceeding exports by around 219 065 t (year to October 2018). l

Tons

Jan-18 Feb-18 Mar-18 Apr-18 May-18 Jun-18 Jul-18 Aug-18 Sep-18 Oct-18 YTD Total 49 297 86 853 51 541 89 453 94 128 139 104 26 487 65 852 131 914 115 151 849 781 64 243 57 122 57 305 46 913 73 424 66 639 66 412 73 557 63 047 62 053 630 715 14 946 -29 731 5 765 -42 540 -20 704 -72 465 39 924 7 705 -68 868 -53 097 -219 065

Import Export

Difference Currency

12,2 11,8 11,8 12,1

12,5

13,3 13,4 14,1

14,8 14,5 13,1

Researching the viability of effluent water in concrete production

of water for construction by as much as 75%. “In this instance, effluent water does not refer to sewage but rather to water from sewerage plants that has gone through all cycles of treatment except naturalisation in a maturation pond. This type of water is often used for irri- gation and is not disallowed according to national standards nor is provision made for it in SANS 51008 water for making concrete because, until now, no specific testing has been done,” explains van Wyk. “As a result, we are currently com- piling a testing which will enable us to run an eight-week study and collate results including chemistry and all the parameters surrounding the water and then monitor its effect on the mixing, setting, curing and strengths of the

A joint initiative of the City of Cape Town and the Southern Africa Readymix Association (SARMA) is underway to research the effective usage of effluent water to manufacture concrete and concrete products. Until now, no specific standards exist to allow the use of water other than “potable” water to be used in the process. However, in light of the recent drought in the Cape Town region, concerned SARMA members have joined forces with Cape Town Municipality to work together to use effluent water that might otherwise ease the water prob- lems in the region. According to SARMA director, Johan van Wyk, if a suitable solution can be found it will not only have a positive effect on water supplies and the envi- ronment but will also reduce the cost

Johan van Wyk, SARMA director.

concrete,” he adds. “This will then be compared with current concrete standards and data to make a finding. And, it must be said, that our preliminary findings are positive and gives hope for a major evolution in the way we make concrete in dry climatic regions,” says Van Wyk. l

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MODERN QUARRYING QUARTER 1 - 2019

ASPASA INVITED TO GIVE INPUT INTO THE MINING CHARTER

says Pienaar. There could be some small issues to be addressed, but Aspasa will, once the Charter and Guidelines have been finalised, hold workshops to explain some of the issues to its members.” l

Now, with government’s assistance, the South African Coal Ash Association (SACAA) has been given a target to increase ash usage to 20% of offtake and to create 26 000 new jobs in the process within the next five years. In addition, start-up ash operations can expect some kind of assistance from government, generators, SACAA and academics to extract the maximum potential out of ideas that are deemed to be viable. SACAA general manager, Mark Hunter, says the association is looking for industrial entrepreneurs to assist in identifying and developing viable busi- ness opportunities for the use of waste ash generated by producers via their boilers. As the second biggest waste stream (after organic waste that is sent to landfill), coal ash is becoming a headache for the country as space is running out of space to dump the ash. He proclaims that reaching the 20% target is not only possible, but prob- able if some viable alternatives can be found to dumping. This will require close cooperation between role play- ers and speedy facilitation between very stringent legislations, as has been the case in the past. “Aspasa was very proud and pleased of its work when the Mining Charter was published, as it was apparent that its input was taken into consideration when the final draft was released,” says Pienaar. Aspasa was then again invited to participate in the drafting of the Guidelines that will accompany the Charter. One of the main issues that Aspasa has previously raised as far as this is concerned is that of community involvement. “Aspasa developed a Guideline document with some ideas on how to handle these situations, which was sub- mitted to the DMR’s drafting team,”

Recognised for its contribution to the surface mining industry, Aspasa was recently asked by the Minister of Mineral Resources to submit its ideas on behalf of small miners. Aspasa was afforded an opportunity to do a presentation to the drafting team at the Department of Mineral Resources (DMR). “It was with a big relief that those involved in the DMR teamwanted to hear how big mines differed from small mines. This concept has never been previously agreed to by the legislator,” says Nico Pienaar, director of Aspasa. Aspasa came up with differentials in the sizes of mines aimed at giving the smaller mining operations some relief from having to comply with

Nico Pienaar, director of Aspasa.

Ash is the 21st century’s next big thing

With a little innovation and a sound business plan any South African stands to make a fortune out of the millions of tonnes of coal ash produced by our generators annually. With mountains of ash available at all of South Africa’s coal-fired power stations – Eskom, Sasol and other smaller producers – there is no shortage of supply and any- one wishing to make use of the “Grey Gold” is likely to get it at low or no cost provided they can prove that they have a viable usage and that the operation will generate revenue and jobs. Already 10% of the total 50-million tonnes of ash produced per year is used in the manufacture of cement powder and concrete bricks for the building industry, as well as to treat acid mine drainage and to remediate soil for agriculture and other land uses. However, this is just the “tip of the iceberg” and experts have already identified a host of other uses, includ- ing alternative building products, volumisers for plastics manufacture, contouring for road, rail and landscap- ing infrastructure, as well as thousands of other uses.

Mark Hunter, GM of SACAA.

government and other role-players who also fully understand the urgency of the matter and will likely pull together to make it happen. l

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QUARTER 1 - 2019 MODERN QUARRYING

INDUSTRY NEWS

Q3 ACI shows further improvement in sector activity

The ACI is now more than 9% higher than after the sharp decline that occurred in the first quarter of 2018.

Afrimat, the JSE-listed open pit mining company providing industrial minerals, bulk commodities and construction materials, released the findings of its Afrimat Construction Index (ACI) for the third quarter of 2018. The ACI is a composite index of the level of activity within the building and construction sectors, compiled by renowned economist Dr Roelof Botha on behalf of Afrimat. According to Botha, the index level recorded in the third quarter of the year increased by almost 4% over the second quarter figure, following an impressive gain of almost 7% between April and June. The ACI is now more than 9% higher than after the sharp decline that occurred in the first quarter of 2018. “This reflects welcome and broad-based recovery of the level of activity in the South African construction sector, with all of the eight constituent indicators recording gains over the second quarter. It is also encouraging that the overall result has improved by 17,6% since the first quarter of 2011, the base period, which is considerably higher than the increase in the country’s real GDP of 11,2% over this period.” Botha indicates that the best performers during the third quarter of 2018 were the value of hardware sales, the value of buildings completed and building plans passed in the country’s larger municipalities, and the volume of building materials produced. “Since the base period for the Index in the first quarter of 2011, all eight indicators have also recorded gains, with the most impressive ones being employment in construction, salaries and wages in construction, the value of hardware sales, and the value of buildings completed in the larger municipalities.” He further points out that the Index provides a balanced and realistic view of the level of activity in the construction sector as it evens out the contradictory trends that are often portrayed by the individual components that comprise the ACI. l

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MODERN QUARRYING QUARTER 1 - 2019

As part of the warranty, Pilot Crushtec International’s Metso-certified technicians will undertake field inspections every 1 000 operating hours.

ON THE COVER

USHERING IN AN INDUSTRY FIRST

In a ground-breaking development, Metso and its southern African distributor, Pilot Crushtec International, have rolled out an industry first, standard 5-year/ 10 000- hour warranty on all Metso crushers and screens. The move ushers in a new era in the crushing and screening industry where a 1-year/2 000-hour warranty is generally the norm on these mission critical assets, writes Munesu Shoko .

A warranty is a valuable component to any capital equipment purchase, especially mission critical and big-ticket purchases such as crushers and screens. It assures equipment users that their funds are being well spent and the equipment they are buying will be covered for a period of time, protecting them against defects in materials and workmanship during the warranty period. As one industry expert put it, “a warranty is like health insurance, we hope we never need it but when we do we are grateful we have it”. While different crushing and screening products from different manufacturers may have different price tags, the length of warranties has largely been the same for years, pegged at 1-year/2 000 hours. The longer and more comprehensive the warranty is, the

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MODERN QUARRYING QUARTER 1 - 2019

The comprehensive 5-year/10 000-hour standard warranty includes extended warranties and scheduled inspections with Metso-certified technicians.

KEY TAKEAWAYS

It is a significant upgrade on the industry-wide 1-year/2 000-hour warranty

Pilot Crushtec International now offers Metso’s 5-year/10 000-hour warranty on all Metso crushers and screens in southern Africa

The pertinent reasoning behind the extended warranty is the fact that the initial capital investment on mobile crushers and screens is high. Therefore, to retain the value on the product, the warranty is a significant component

As part of the warranty, our Metso certified technicians will undertake field inspections every 1 000 operating hours

lower the overall potential cost of ownership for owners. With that in mind, Pilot Crushtec International and Metso are setting new standards with a standard 5-year/10 000- hour warranty for southern African customers. Francois Marais, Director – Sales & Marketing at Pilot Crushtec International, says the ground- breaking initiative is a true indicator of Metso’s confidence in its product. It is also a sign of service commitment from Pilot Crushtec International as the exclusive distributor of Metso’s aggregates products and services in southern Africa, including static, tracked and wheeled crushers, scalpers and screens. “As Pilot Crushtec International,

we have been offering the warranty for the past six months on a pilot basis just to gauge the level of interest and feedback from customers. Effective 1 January this year, we were able to broker a deal with our principal, Metso, to standardise the 5-year/10 000-hour warranty across the whole Metso range we supply,” says Marais. “The initiative is in the best interests of the consumer. A longer product warranty gives customers some extra coverage for their big-ticket purchases, along with a little more peace of mind. From an original equipment manufacturer (OEM) perspective, it says a lot about the confidence in the brand. From a supplier point of view, it also means that we want to be there for our customers for the long haul, and be involved in their businesses with a vested interest,” explains Jorge Abelho, Director – technical and customer support at Pilot Crushtec International. Offering in detail As part of the Metso Life Cycle Services for aggregates, Metso has always offered its Equipment Protection Services (EPS) as an optional extra. The comprehensive plan includes extended warranties and scheduled inspections with Metso- certified technicians. EPS is built on three core elements: extended warranty to 5 years or 10 000 hours; scheduled inspections with Metso-trained and certified technicians, coupled with OEM parts recommendations; and maintenance plan-

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QUARTER 1 - 2019 MODERN QUARRYING

money, but with an extended warranty of this nature, customers have a peace of mind,” adds Abelho. Marais says the pertinent reasoning behind the extended warranty is the fact that the initial capital investment on these machines is very high. Therefore, to retain the value of the product, the warranty is a significant component. “If everything is done according to OEM spec and standards, the machine will definitely give the owner a longer lifespan, while it retains the value of the investment,” says Marais. Change of mindset Abelho says the new extended stan- dard warranty changes the mindset across the industry – instead of just pushing tonnages, it’s now about getting the life out of the machine – 30 000 to 40 000 hours life without major issues. “From the customer and the operator to our technicians, the mindset will change because the machine needs to run for the next 10 000 hours hassle-free, so the level of attention, even the smallest of details, is very high,” he says. Abelho says the new extended warranty will also ensure the life out of a machine because for the first 10 000 hours, there is no temptation to go the pirate parts route for customers, ensuring that the machine is serviced and maintained the Metso way. “What I have noticed previously is that whenever a machine was still within the 2 000-hour warranty, the operator will always call the service provider to come and have a look if any problems accur. Once the machine is out of warranty, the operator “makes a plan”, because they feel “it’s now their problem”. Now if you tell them that we have got you covered for the next 10 000 hours, they will always call on you to do the proper repair required on the machine, giving it the life it deserves in the process.” From a supplier point of view, Abelho says this also means that Pilot Crushtec is getting involved in customers’ businesses a lot more. “Within the first 10 000 hours, we will learn a lot. The constant engagement helps us stay in touch with operational reality and we can also transfer the lessons learnt from one site to the other,” concludes Abelho. l

ON THE COVER

By focusing on preventative maintenance, with the use of 100% OEM parts as required, an EPS plan helps customers proactively manage and reduce the risk of machine failure throughout the extended warranty period.

ning and reporting for mobile equipment through Metso Metrics Services. The extended standard warranty gives equipment owners the much-needed confidence in their cost structure by anticipating and minimising unexpected equipment failures. Along with extended warranties that cover repairs or replacements on key parts that need to be replaced, the plan includes comprehensive inspections and other services to keep Metso equipment running smoothly at all stages of operation. The Metso extended warranty covers the whole machine, excluding wear parts, for the first 4 000 hours, which is double the industry-wide standard warranty. From 4 000 to 10 000 hours, which is when fatigue often starts setting in, Metso covers all the critical components. “It made sense for us to package it as a standard offering. It’s a massive leap in our value offering and draws a line in the sand for our competitors. We believe in our quality and know that if customers prescribe to OEM servicing levels, their equipment will last longer and perform better. The extended warranty also assures our customers that the OEM and the supplier are ready to deliver on their promise,” says Marais. “By focusing on preventative maintenance, with the use of 100% OEM parts as required, an EPS plan helps you proactively manage and reduce the risk of machine failure throughout the extended warranty period. As part of the warranty, our Metso certified technicians will undertake field inspections every 1 000 operating hours. During the visits, they will identify preventative and/or correction actions and provide recommendations accordingly,” explains Abelho. Changing the landscape The new standard warranty from Metso and Pilot Crushtec is definitely a game- changer in the industry. Marais is of the view that because of the hard industrial applications crushing and screening machines are subjected to, it’s almost guaranteed that they will at some point break. He therefore reasons that the industry-wide 1-year/2 000 hours warranty is definitely trivial. “The warranties and service plans in the industry are generally not geared at ensuring long-term plans for servicing and maintenance of equipment at an OEM level so that customers can retain their production levels and efficiencies,” says Marais. The same view is shared by Abelho, who says that the 1-year/2 000-hour warranty is not geared at supporting customers for the long term. “Warranty is easy to support in the first 2 000 hours. It’s after the 2 000 hours that you start getting real problems. When one buys a new machine, within the first 2 000 hours, the stuff that goes wrong is mostly mistake driven, not design based,” says Abelho. “It’s only after the 2 000 hours when serious problems such as cracks on track frames and broken feeder bins start to happen as fatigue sets in, with machines starting to be stretched hard. These failures are the ones that cost customers

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MODERN QUARRYING QUARTER 1 - 2019

BLASTING

AT THE BLASTING EDGE Blasting practices at mines and quarries have undergone many changes in the recent past and continue to be refined and reconfigured to meet the demands of today’s mining and quarrying needs as operations seek to gain further improvements in safety, mining efficiencies and productivity, while reducing costs, writes Munesu Shoko .

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KEY TAKEAWAYS

In today’s aggregate production operations, there is stiff competition based on quality and cost

One parameter that has a significant effect on unit costs in aggregate mines is the cost of drilling-blasting

In recent, there been greater focus on the development of new electronic products that allow to leverage blasting products and practice to achieve lower-cost production cycles and improved safety

BME is taking advantage of the latest move towards digital technology with its AXXIS GII electronic detonator being at the forefront

Blasting is one of the most important operations, and has substantial technical and economic effect on mining/quarrying projects.

I n today’s aggregate production operations, there is fierce competition based on quality and cost. Primitive and unplanned work, not using technology in a rational way and ignoring research and development findings can all negatively affect producers in this competitive environment. One parameter that has a significant effect on unit costs in aggregate mines is the cost of drilling-blasting. Blasting is one of the most important operations, and has substantial technical and economic effect on the mining projects. In such projects, the prime aim of blasting operations is rock fragmentation that is necessary for subsequent processes – such as such as load and haul, crushing and screening – to achieve a higher efficiency. Good blast design and execution are essential for successful mining oper- ations. Improper or poor practices in blasting can have a severely ill impact

on the economics of a mine/quarry. How significant is the blasting pro- cess to the overall mining efficiency and productivity of the quarry? Research company, ResearchGate finds that conditions of the drilling and blasting process directly affect the loading and hauling processes, which are considered among the major steps of mining. Selecting the wrong blasting pattern may cause inadequate loose volume at the end of the explosion and/or unwanted

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QUARTER 1 - 2019 MODERN QUARRYING

BLASTING

BME’s AXXIS system – which has built a strong customer base in the mining sectors of Africa and Australia especially – has been behind the world’s largest surface blasts.

savings and vibration benefits in the blasting operations. Rorke notes that development of new technology has become more exponential in recent years with the introduction of electronic detonators and digital data measurement and management systems (this is mani- fested in data from drones, logging devices, digital cameras and the electronic detonators themselves). “The two recent trends allow for flexibility and control, which has resulted in significantly better blast results with much less risk to envi- ronmental issues such as vibration, air blast and fly rock,” says Rorke. Digital tech BME is taking advantage of the latest move towards digital tech- nology with its AXXIS GII electronic detonator being at the forefront. “Our BlastMap III software provides users with the ability to design and simulate their blasts and BME’s XploLog system provides electronic logging of the drilling and charging operations. The data is useful in achieving continuous improvement by analysing trends and identifying out-of-specification performance,” says Rorke. The AXXIS GII detonator is a stan- dard size detonator that will func- tion in all standard sized boosters also used in non-electric blasting.

material sizes in the size distribution of the loose material. The pieces that do not comply with the feed opening of the crushing-screening facility have to undergo a second crushing process. The secondary crushing is undesir- able because it causes both loss of time and cost increase. Thus, increased secondary crushing adversely affects production costs. The same view is shared by Tony Rorke, Specialist AXXIS Application at BME, who says that the blasting process is critical to overall mining efficiency. “A poor blast result usually means sub-optimal fragmentation and tight muck- piles. This slows the entire downstream processes, from loading through to crushing,” he says. Rorke adds that the costs related to loading and crushing are a few orders higher than the cost of explosives, and poor blast results, therefore, have a major impact on cost and being able to extract value at the planned rate. “An additional cost is to the environment – where the extra energy expended in loading and processing, the coarser than planned rock produces about four times the greenhouse gasses,” says Rorke. Rorke adds that most quarries are close to residential and commercial areas, thus providing a huge burden on environmental control for them. “Blasting is one of the main sources of risk to the surrounding communities and infrastructure and if not properly controlled, it can result in shutdown of the operation.” Evolving industry From the earliest days of blasting with black powder, there have been steady developments in explosives, detonating and delaying techniques and in the understanding of the mechanics of rock breakage by explosives. What are some of the recent notable trends in blasting technologies? Rorke says that development in explosives and blasting technology has been linear over the years, first with the introduction of ANFO as a blasting agent and then water-proof emulsions and blends in the latter part of the 20th century. ResearchGate notes that there has been a significant focus on the devel- opment of new electronic products that allow to leverage blasting products and practice to achieve lower-cost production cycles and improved safety. New tools with better software packages are coming to the market that allow measurements of blasthole deviation and blast fragmentation. Latest digital electronic detonators with high timing accuracy help achieving safety, cost

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MODERN QUARRYING QUARTER 1 - 2019

Improper or poor practices in blasting can have a severely ill impact on the economics of a mine/quarry.

were fired in a single shot at a large Australian coal mine recently. “Electronic detonation has become increasing popular due to its reliability, accuracy and flexibil- ity, making blasting practice more predictable and allowing for larger and more cost-effective blasts,” says Rorke. “The ability to analyse data both historically and in real time provides a major productiv- ity advantage and allows for the capability of accurately determining cause in blasts that may go wrong.” As technological development continues apace in the blasting industry, what are some of the developments that will likely take place in blasting technology in the near future? Rorke believes that digital technology is expanding the capability of providing efficient blasting and the major development will be in this field where electronic detonators, digital data recording, modern data analysis utilising artifi- cial intelligence will be the focus for improving blasting in the future. “The application of charging and blast timing will rely more heavily on global positioning that provides real-time information on hole charging and firing time choices. The future is bright. Where are my dark glasses?” concludes Rorke. l

Tony Rorke, Specialist AXXIS Development Application at BME.

AXXIS GII detonators use 2-core double insulated downline cables. Higher resistance to electrostatic discharge and high induced ground currents make the GII detonator safer to use in all mining conditions. BlastMap III is BME’s complete blast planning, design and analysis software. It is a powerful and modern software that allows design of the blasts from hole layouts to charge quantities, deck charging and blast timing. BME’s AXXIS system – which has built a strong customer base in the mining sectors of Africa and Australia especially – has been behind the world’s larg- est surface blasts, measured by the number of electronic detonators fired in a single blast. At Zambia’s Kansanshi Mine – the largest copper mine in Africa – 6 690 electronic delay detonators were successfully initiated in one blast last year using AXXIS. Elsewhere, a world record of over 7 400 AXXIS detonators

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QUARTER 1 - 2019 MODERN QUARRYING

Regarded as the main process in aggregate production, crushing is the first controlled size reduction stage and is the basis for optimal further size reduction. It is, therefore, important that when choosing a new rock crusher the first thing you need to know is which one best matches your material – and it is imperative to find the right one the first time, writes Munesu Shoko . ATTAINING COST-EFFECTIVE CRUSHING

CRUSHING

B y tonnage, crushing is by far the largest process operation in aggregate processing. To execute this process cost- effectively, it’s always important to deploy the correct crusher for the ideal application. This not only saves you time, but it will also save you money in the long run. Just how important is crushing in the whole aggregate production equation? To reiterate the significance of the process, Heath Dickson, national mining sales manager at ELB Equipment, says “simply put, without crushing, in specification aggregate would not exist”. JD Singleton, process director at Weir Minerals Africa, says size reduction in aggregate production is required to achieve the different product gradations used in different

serve as aggregate, crushing forms a vital and cost-effective part of the aggregate production process. “It allows us to reduce the particles to a required size under applied stress through one or more crushing stages in conjunction with screening to achieve the required specification of the final product,” he says. Van Rensburg adds that key aspects of designing and implementing a crushing circuit include, firstly, understanding asmuch as possible about the source material – such as the size of the rock entering the process, the hardness of the material and its abrasiveness. “Most importantly, the designmust focus on exactly what output the customer requires – both in terms of particle size and volume of output in a specific timeframe. On the strength of these considerations, it can be decided whether the processmust be single-stage or multi-stage, and the

end processes. “The primary objective of a crushing stage is size reduction, so having the correct crusher in the correct duty is essential for quality aggregate production,” he says. Sandro Scherf, CEO of Pilot Crushtec International, shares the same view, saying that the crushing stages are critical to achieving the right quantity and quality of aggregate products. “Similar to driving a vehicle, to reach top speed you need to go through various gears; in aggregate production, you need to go through various crushing stages. The number of crushing stages will vary depending on production requirements such as the quantity you need to produce and the specifications of the final product,” says Scherf. Dewald Janse van Rensburg, MD of B&E International, says by applying compressive strength to the strong and brittle natural rock types that

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MODERN QUARRYING QUARTER 1 - 2019

Impact crushers can be classified as primary/ secondary crushers or secondary/tertiary crushers.

KEY TAKEAWAYS

screening aspects can be designed aligned with this,” explains Van Rensburg. Tyron Ravenscroft, Finlay Product Manager at Bell Equipment, says without crushing, very little aggregate would be produced from purely using explosives to blast the natural rock. “Therefore the crushing stage is a vital necessity to be able to produce high quality aggregates. However, screening the crushed material is just as important to be able to produce the different aggregate sizes, which then become a valuable and sellable product,” says Ravenscroft. Johann Pruewasser, engineer at Keestrack, says the importance is extremely high because the crushing stage influences the overall quality of the final product. He adds that the costs of processing are mainly dependent on the crushing system and the energy demand.

By tonnage, crushing is by far the largest process operation in aggregate processing

To execute the crushing process cost-effectively, it’s always important to deploy the correct crusher for the ideal application

Jaw crushers are typically used in a primary crushing station – to take the run of mine and produce a feed to the secondary cone crushers

The VSI is a critical part in obtaining high specification road stone, or as a pre-milling crusher to increase mill throughput in mining applications

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CRUSHING

The VSI is a critical part in obtaining high specification road stone, or as a pre-milling crusher to increase mill throughput in mining applications.

A jaw crusher is universally applicable in primary crushing applications and is used to reduce large material to a more manageable size.

Trio jaw crushers for use in primary crushing.

jaw crushers are provided for abrasive to very abrasive materials as primary crushers. Cone crushers are mainly used for abrasive to very abrasive materials as secondary crushers. Ravenscroft agrees, saying that a jaw is predominantly classified as a primary crusher, by virtue of being the first stage in the crushing process. “It caters for large feed size and a high production output, with a crushing ratio of 4/5:1,” says Ravenscroft. Secondary and tertiary crushing Singleton says jaw crushers are typically used in a primary crushing station – to take the run of mine (ROM) and produce a feed to the sec- ondary cone crushers. “Cone crushers are used in secondary and tertiary crushing stages. The reduction per stage is typically between 3:1 and 4:1, depending on the application. A cone crusher can produce any aggregate size fraction you require, provided you stay within the required reduc- primary gyratory crushers (similar in operating principal to a cone crusher), cone crushers are generally used as secondary or tertiary crushers (with some exceptions such as in coal applications). “Cone crushers are also compression crushers and offer a greater ability to adjust your final product size and shape than a jaw crusher and operate at a lower cost per tonne than an impact crusher in tion ratios,” says Singleton. Scherf says while there are

Right crusher for the right application

crucial to design and manufacture crushing plants with appropriately sized and staged equipment, as well as the right screening and other infrastructure, to suit the purpose. “This requires understanding a range of factors that might affect the crushing circuit; at B&E International, we are therefore able to work closely with customers not only on designing and building the plant but with a number of related services,” says Van Rensburg. “For instance, we can help find and approve a quarry site, and test the stone available. By assisting with blast design and practices we help gather the information required to arrive at the correct crushing plant application,” says Van Rensburg, adding that blasting techniques and fragmentation achieved together with throughput requirements will determine the size of the jaw crusher required. Pruewasser reasons that generally

It is important to deploy the right crusher for the right application. There are different types of crushers available in the market, ranging from jaws to cone and impact crushers. Scherf says for the long-term profit- ability of any operation, it’s impera- tive to have the correct type and size of crusher in a correct application. He reasons that a jaw crusher is universally applicable in primary crushing applications and is used to reduce large material to a more manageable size. “From the hardest of granite or basalt, to the softest of sedimentary, the jaw crusher is a compression crusher that takes large primary material and reduces it to a manageable size for further crushing. In some cases, granulator jaw crushers can be used in secondary applications,” says Scherf. Van Rensburg says each customer’s application will be specific, so it is

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It is crucial to design and manufacture crushing plants with appropriately sized and staged equipment.

to 10:1. They are more acceptable to larger feed sizes than cone crushers, but still giving an output size similar to cone crushers. As far as the vertical shaft impactor (VSI) crusher is concerned, Scherf argues that this is the most misunderstood of all crushers and often called a ‘shaping’ crusher. He reasons that the VSI is an impact crusher that uses a rotor to accelerate material and sling it against a rock wall built around the rotor. The VSI is a critical part in obtaining high specification road stone, or as a pre-milling crusher to increase mill throughput in mining applications. It is often used in sand making applications, especially in applications such as silica sand and other abrasive feeds where the operating cost of a HSI would be too high. Geology matters Is geology a factor that determines the type of crusher to be deployed in an application? Singleton says crush- ers will work in most applications, and it only depends on how long it will last. “By doing proper applications and process engineering when you select the crusher and consider the duty, as well as the ore characteristics like solid specific gravity, abrasion index, bond work index, among other parameters, one will be able to achieve the required output no matter the geology,” he says. Dickson says the end result the client is looking for would determine

what crusher gets deployed for the job. “Ideally you would not want to necessarily deploy an HSI into a high silica application, but if the client is looking tomaximise the fines generation and understands the wear costs or rand per ton cost, this could be an option,” says Dickson, adding that capex vs tonnage can be a major factor when deciding what crusher to deploy. Ravenscroft is of the view that knowing the geology of the material is very important as materials react differently when under pressure or impact in the crushing chambers. “Knowing the geology of the material assists in specifying the correct crusher for the specific rock application. Further to this, knowing the product size distribution of the ROM allows the crusher to be spec’d correctly. Should there be a high fraction of fines in the feed ROM, pre- screens can be fitted to the jaw, cone and impact crushers,” he says. According to Scherf, in order to operate economically and safely, having the correct crusher for feed material is critical. For instance, in a coal application, using a cone crusher carries a very high risk of igniting the coal, due to the compression of the material in a small chamber. He is of the view that using an HSI on a very hard granite or basalt can result in the hammers breaking at worst, or very high operating costs at best. “Knowing the silica content or abrasion index of the feed material is critical in selecting not only the

hard or abrasive feeds,” says Scherf. Ravenscroft says a cone crusher is classified as a secondary and/or tertiary crusher. “It further reduces the size of the rock at a 4/5:1 ratio and supplying desired end product sizes. Cone crushers can also supply a quality shaped product by using the crusher within its desired parameters and crushing ratios,” he says. When it comes to horizontal shaft impactors (HSI), Dickson says as long as the client understands the wear costs and ultimately the rand per ton cost to produce, there is a place for this type of crusher in most applications, especially demolition, recycling of asphalt and applications where the client needs high reduction of material. Scherf says while it can be used as a primary crusher in certain applications, a horizontal shaft impactor comes to the fore as a secondary or tertiary crusher in softer, non-abrasive rocks such as limestone. “As the name implies, it crushes using the impact of the feed material against metal hammers. Perhaps the most versatile of all the crusher types, offering the best in terms of reduction ratio and producing a cubicle product, the operating cost in abrasive or hard feed materials limits its practical applications,” says Scherf. Ravenscroft says impact crushers can be classified as primary/ secondary crushers or secondary/ tertiary crushers. He adds that they have a higher crushing ratio of up

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break it down. Similar to a racing car, using different gear ratios depending on the race track, efficient and economical operation of a plant requires fine tuning to take the material properties into account,” he says. Van Rensburg says a good host rock is vital for production of a quality product, and the geology of the host rock is relevant right from the blasting stages of aggregate production. This tends to affect the size of the material that will report to the crushers, and hence will determine the size of the jaw crusher required at primary stage. “The hardness of the material will also affect the primary crusher selection and may well impact the throughput that can be achieved through the crushing circuit. Silica levels and other abrasiveness factors will influence wear levels, so operators need to be aware that maintenance interventions may be more frequent under these conditions,” concludes Van Rensburg. l

CRUSHING

Impact crushers are used mainly for less abrasive materials as primary and secondary crushers.

manage customer expectations and operating costs, we generally send rock samples to the Metso Lab for abrasion and crushability tests, we can then simulate the plant and provide accurate estimates of the operating cost and ensure we have the correct configuration,” adds Scherf. Scherf also reasons that harder material will have an impact on the number of crushing stages. “The harder the rock the more energy required to

correct crusher, but also the correct wearing materials to ensure a profitable operation,” says Scherf. He adds that rock properties, even on the same rock types, vary considerably as they are produced in a natural and varying environment, not a controlled lab. “Not all granites are the same, a fine grain granite is significantly harder than a coarse grain granite; some will have a higher silica (SiO2) content than others. In order to

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LOAD AND HAUL

The productivity of any surface mine largely hinges on the efficiency of its load and haul system. Yet, loading and hauling run of mine material represents a very significant component of the total operating cost. Consequently, the incentive to reduce cost in this area remains high, writes Munesu Shoko . MAXIMISING LOAD/ HAUL PRODUCTIVITY

T he current aggregates business climate is characterised by price volatility, high labour costs, shrinking margins and increasing operational costs. This is exacerbated by a steady decline in the growth of aggregates demand due to the lack of meaningful construction projects. For quarries to survive and mine profitably, they need to capitalise on the opportunity to improve their productivity and focus on one factor they can control: operational efficiency. Increasing productivity is one of the key drivers to counter diminishing profit margins as it effectively reduces operating costs. However, the emphasis should not only be on increasing output with the same input, but increasing the output while decreasing the input, and ultimately adding optimum value to current resources. Research shows that an increase in production will ultimately decrease the operation’s unit cost, especially fixed costs. Load and haul is probably the biggest cost driver for any quarry. Yet, if properly

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