Inside Mining June 2015

www.miningne.ws

af r ic an u pdates on th e

g ro un d a n d un d e rg ro un d

in the

spotlight Mike Andrews, Sandvik Business Line Manager: Automation

Diamonds

Industry-shaping trends

Finsch

A world-class operation

Lace

Modernisation reaps rewards

Karowe

A place of exceptional diamonds

lab tech

Elemental analysis

Master Drilling Groundbreaking innovation ISSN 1999-8872 • R50.00 (incl. VAT) • Vol. 8 • No. 06 • June 2015

contents Endorsed by

Af r ic a n u pdates on th e

June 2015

g rou nd a nd u nderg rou nd

on the cover

P4

The ingenuity of human innovation is clearly demonstrated in Master Drilling's method of shaft raising, not sinking. What’s more, the company's approach delivers mining’s three key objectives: safety, productivity, and cost-efficiency.

8

EDITOR'S COMMENT

3 Diamonds are forever COVER STORY

4 Groundbreaking innovation Africa round-up

7 News from around the continent in the spotlight

8 Mechanisation and automation ECONOMICS, FINANCE & RISK

14

10 The criticality of

collaboration

12 Industry-shaping trends commodities: DIAMONDs & GEMS

14 New and greater opportunities 17 Finsch: A world-class operation 22 Lace: Modernisation reaps rewards 27 Karowe: A place of

exceptional diamonds

30 Guidelines for gem mining DRILLING & BLASTING

33

32 Tracking and control systems 33 Delivering the bottom line PIPES, PUMPS & VALVES

34 Fissure water beneficiation 37 Organisms in fissure water MINERAL ANALYTICS

39 Elementary, my dear Watson 40

40 Characteristics of

coal

In sid e M in in g 0 6 | 2015

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Diamonds are forever I

n this issue, we look at the technology that will take on the development of twin 1.2 km deep ventilation shafts, from the bottom up. Quite the opposite from the traditional drill and blast method, which is topdown, this bottom-up approach delivers increased safety, a shorter shaft development time, and a significant reduction in costs. It’s worth a read.

Then, there is the world of mine mechanisation and automation. With labour instability so prevalent in South Africa, coupled with low productivity and high labour costs, new mines are being specifically designed to employ mechanisation and automation as the preferred mining method. Old mines, too, are looking at this method as a means to improving profitability. Whether it is a surface mine or an underground mine, the benefits are clear, and very present. The Finsch diamond mine near Postmasburg is such a mine. Their block caving operation is The lack of exploration quite exemplary, and a culture shift. will impact the Another old pit mine that is being modernised usfuture – quite ing underground block caving is the Lace diamond mine near Kroonstad. Of interest are the diamond negatively finds coming out of the old tailings dumps. De Beers, too, are selling their old Kimberley mine tailings dumps. So, it would be true to say that one man’s waste is another man’s treasure. Even so, in the vast expanse of Botswana’s Kalahari Basin, on its northern edge, just south of the Makgadikgadi Pans National Park, and in one of the world’s richest diamond-bearing-kimberlite areas, is the Karowe mine – a place of exceptional diamonds.

But, what of diamonds, and where is the market going? The reputable McKinsey & Company’s research into the world’s diamond markets revealed seven specific trends that will shape the industry going forward. Interestingly, there are one or two surprises, as well as a couple of good opportunities, and a real threat from synthetic diamonds. There have been recent developments in drilling technology; the MD5150 Track Drill from Caterpillar, which delivers maximum productivity as the main advantage, provides fast cycle times and low operating cost in a fully automated setting. It can even change its own rods.

From the drill core to the laboratory, elemental analysis – the process whereby mineral samples are analysed for trace elements and composition, and which is fast becoming the critical success factor in mining today – takes on new and advanced technology to make decisions faster and better. This applies to mine water too, especially fissure water. A young, but talented, engineer takes us through a strategy developed for the beneficiation of wastewater streams emanating from fissure water recovered from a gold mine operation in the west of Johannesburg – a strategy that was tested for viability in a pilot study.

Last, but not least, uncertainty prevails. The MPRDA legislation remains unfinished. The South African government and the mining industry are at loggerheads over the latest BEE audit and to cap it all, the trade unions are intent on buckling an already struggling gold sector. The National Union of Mineworkers (NUM) and the Association of Mineworkers and Construction Union (AMCU), the latter outdoing the former in a bid to entice members to join it as the better trade union, threaten the sector with a longer strike than the five-month, 2012 platinum belt strike. It may be posturing, but it may also be a real threat. Regardless, it would seem ignorance and ideology prevail over sensibility and reality.

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In sid e M in in g 0 6 | 2015

3

cover story

Groundbreaking innovation

The ingenuity of human innovation is clearly demonstrated in this method of shaft raising, not sinking. What’s more, it delivers mining’s three key objectives: safety, productivity, and cost-efficiency.

R

aiseboring is a bottom-up approach and quite different to the traditional drill and blast method used to sink shafts on mines, be these main or ventilation shafts, or decline tunnels. The technology used integrates into a productive unit, delivering increased safety, shorter shaft development time, and significantly reduced costs.

Master Drilling, a world leader in drilling services, with 30 years’ experience in surface and underground raiseboring, box hole boring, blind hole boring, and underground and surface exploration drilling, has developed one of the biggest raiseboring machine in the world for a project in Palaborwa.

With their project management expertise, which includes exploration-stage drilling (principally exploration, diamond-core, and percussion drilling), capital project-stage drilling (principally raiseboring) to production-stage drilling (principally raiseboring and blast-hole drilling), they are well positioned to take on the twin 1.2 km deep, 6.1 m diameter ventilation shafts. With

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specialised in-house design, manufacturing, training and maintenance capabilities, this allows Master drilling to tailor-make turnkey solutions to meet the specific conditions and drilling requirements of its customers.

Different uses Raiseboring is used primarily in mining. It has revolutionised the way in which shaft sinking is usually done. Not only is it safer, but it has also made mining easier in many ways. This method of shaft development is used for: • ventilation, especially to the lower levels that receive little air, and need it • vertical shafts and incline tunnels for the miners, their tools, and mined ore to be easily transported in and out of the mine • drainage • certain hydro-electrical projects • difficult horizontal and low-angle drilling.

Raiseboring creates a circular hole, up to 6.1 m in diameter and as much as 1.2 km deep, between the surface and a lower level

or between two levels within a mine. It eliminates the need for explosives, which, as we know all too well, can be dangerous. Explosives lack precision, affect rock integrity, and can cause immediate or delayed rock falls, injuring and even killing miners, and it wastes production time as the area to be blasted needs to be evacuated.

Raiseboring and drilling machinery is precision-operated, to a very high degree of accuracy, adding to the overall effectiveness of the technology. To prevent the process veering off course, this technology has built-in directional monitors and instruments that are able to make the necessary line adjustments so that the process can continue running precisely as planned. The raiseborer is set up on the surface, or the upper level of the two levels to be connected, on an evenly laid, suitably reinforced platform (typically a concrete pad). If on the surface, the concrete ABOVE Media and industry delegates at the launce of the new and one of the biggest raisebore drills

drilling cover & blasting story

pad will have pile founDiagram 1 The raiseboring process dations. A small-diameter hole (pilot hole) is drilled to the required level. The diameter of this hole is typically between 230 mm and 445 mm, large enough to accommodate the drill string. Once the drill has broken into the opening on the target level, the bit is removed and a reamer head, of the required diameter of the excavation, is attached to the drill string and raised back towards the machine. The drill cuttings from the reamer head fall to the floor of the lower level. The finished raisebore The model of the reamer to be shaft has smooth walls and may not reused in the quire rock bolting or other forms of ground Palaborwa project support, except in certain instances where there are fractures.

A new mine will not have this Advantages in place, but an This is possibly the quickest, most cost-efexisting mine, extending its underground fective, and safest method one can use to operations and needing a second or create a shaft or an incline tunnel. The three third shaft, is perfectly suited to using advantages, which tie back to mining’s fithis technology. nancial key objectives, are: • Safety: It does not use explosives. As such, it does not compromise the integKey considerations rity of the surrounding rock as a blast • If a raiseboring machine is used in the does. With rock integrity maintained, mine and not at the surface, drifts – the rock falls do not happen. The equipment horizontal tunnels in a mine – should does the work, therefore reducing the be the first consideration. Flexibility number of personnel required to operate and manoeuvrability of the machine, the machinery, and removing them from as far as weight and operating height any potential hazards as they do not are concerned, is critical, particularly have to enter the shaft. underground. The size and the weight • Productivity maintained: In using of the raiseboring machine proposed this technology, work is completed must take into account the distance quickly and ensures a continuous cycle between drifts, one level to another, and in mining operations. the supporting rock structure. The main • Reduced time and costs: With fewer shaft lift will need to be able to carry the workers required and less time spent on load, and the machine will need to fit over drilling, blasting, and clearing, raiseboror under obstacles, or through and in ing and raise drilling can be up to four tunnels, to where you need it. times faster than conventional blind • The electrical power requirement of the sinking methods. This reduces the overproposed raiseboring machine is another all shaft, or incline tunnel, development important factor to consider. If drilling, in costs significantly. hard rock, through one level to another, a powerful machine will be needed.

Power consumption is relative to size Disadvantages and capability.

For raiseboring to be used, the technique • The quality of the raiseboring technology requires the existence of a lower tunnel, to used is vitally important from a which the pilot hole can be drilled, and the productivity perspective, especially reamer transported.

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the drill rods, the drill string, and the reamer, as will be the proposed machine’s capability.

Lonmin case reference Daniel Pretorius, CEO and founder of Master Drilling, told Inside Mining that Master Drilling has had a long and fruitful relationship with Lonmin.

The company recently completed the 1 000 m Rowland shaft at Lonmin using similar technology to that which has been mentioned throughout this article. This project was accomplished within budget, on schedule, and with no incidents, accidents, or damage to property. The operation was a huge success and the company employed three local community members as part of its drilling crew.

“The new crew members will now be moving with us to the next job, as they have proven their competency and fit in well with the company culture,” says Pretorius.

Daniel Pretorius, CEO and founder of Master Drilling

In brief Building on an exceptional track record, expertly crafted over 30 years, Master Drilling currently has over 100 raiseboring rigs in operation around the world, in addition to its diverse drilling fleet, which includes rock boring and slim drilling solutions. This pioneering technology transforms and improves the industry, and further places South Africa on the map in taking mining into the future.

www.masterdrilling.co.za

In sid e M in in g 0 6 | 2015

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africa round-up

Mining news

from around the continent in association with

Two coal blocks awarded, plans for a power plant Kenya has selected China’s HCIG Energy Investment Company and Liketh Investments Kenya to develop

hoping that coal from the Mui basin, where block C is estimated to contain a minimum of 400 million tonnes, will help save foreign exchange by cutting import costs. Some of the coal is set

President Kikwete greets Philippe Dongier, the World Bank’s country director for Burundi, Tanzania, and Uganda

Power Construction Company for the project. The new power plant will cost about $2 billion, about $500 million of which ish to be funded through equity and the balance through debt.

Kenya wants to expand its electricity generation capacity by 5 000 MW by 2017, from about 2 152 MW now, to lower tariffs and cut costs of doing business.

Tanzania $45 million World Bank loan to improve mining sector

two coal blocks in its eastern region, the energy and petroleum ministry said, in May. The consortium will mine and process coal on blocks A and B within the Mui basin.

The basin is sub-divided into four blocks, namely, A, B, C and D. The deal will also include the construction of a coal-fired power plant using coal from the blocks, and will sell surplus electricity to Kenya’s national grid, the ministry said in a statement.Fenxi Mining Group, another Chinese firm, was, in 2011, selected to develop blocks C and D within the Mui basin.

The East African nation is Kenya’s Mui basin

to go to the cement and steel industries, which import large volumes of coal, and the rest will be used for energy generation, helping to fill a gap that is usually filled by diesel-fired, thermal plants. In September 2014, a consortium led by Kenyan firms Centum Investment and Gulf Energy won a government tender to build a 1 000 MW, coal-fired power plant in Lamu. The two firms joined forces with Chinese firms China Huadian Corporation Power Operation Company, Sichuan Electric Power Design and Consulting Company, and Sichuan No. 3

The World Bank has approved a $45 million loan for East African country Tanzania in a bid to aid its mining sector, especially among small-scale producers.

The funds will help to create a viable domestic mining industry in poor, rural areas, where unregulated artisanal and small-scale mining takes place, Philippe Dongier, the bank’s country director for Tanzania, said in a statement.

The project will train smallscale miners in jewellerymaking and help them access markets and financing, the bank said. Tanzania, Africa’s fourth biggest gold producer – after South Africa, Ghana and Mali – also has deposits of coal, uranium, diamonds, and precious stones. Dozens of small scale miners are killed each year in collapsing mines in Tanzania, where unsafe and unregulated illegal mining is widespread. The mining and quarrying sector expanded by 5.2% in the third quarter of 2014, from 3.3% in the previous year.

Zimbabwe First-quarter gold production up 25% Zimbabwe’s gold production rose 25%, to 4 180 kg, in the January-March quarter, after small gold milling companies increased output, claims the country’s chamber of mines.

The chamber projected gold production, for the year as a whole, of 16 721 kg, up 8.7% from last year. Gold has been Zimbabwe’s third-largest foreign currency earner, after tobacco and platinum, in the last two years. The chamber said mines were, however, being affected by low international mineral prices, high electricity tariffs, as well as power cuts and higher mining fees imposed by the government.

Meanwhile, the country’s diamond exports fell by 34%, to 5.9 million carats, last year from the eastern Marange region. This, after a slump in production, a junior government minister said, on Wednesday. The Southern African nation is one of the world’s top diamondproducing countries, and is believed to hold 25% of the world’s reserves of opencast extractable diamonds, with Marange fields being its major diamond source.

A rough diamond Source: De Beers Group

Kenya

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7

in the spotlight

Mechanisation

and automation With profitability high on the agenda, a volatile labour market and relatively low productivity are problematic. As such, mining houses are looking at mechanisation and automation. Will this make a difference?

I

nside Mining, in an exclusive interview with Mike Andrews, business line manager automation Southern Africa at Sandvik – a leading supplier of underground mechanised and automated mining equipment – looks at the issues involved.

Is mine automation a relatively simple process or does it require a carefully considered implementation plan. If so, what?

And, when and how does it begin?

MA We believe that the journey to mine automation should be considered as an evolution, developed jointly with our mining customers and Sandvik. Because of this, it requires us to fully understand our customers’ mining applications and their objectives for considering automation. This in-depth understanding requires effort, trust, and significant collaboration to successfully achieve.

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Based on this, we would suggest that the automation journey of any customer requires a thorough implementation plan to completely grasp the full potential. It also needs to be customised to each customer’s mining application, which takes time and considerable thought and discussion. For Sandvik, it all begins with an intrinsic customer need. The needs may be explicitly understood or need to be explored and understood further.

Once all parties understand the need, we seek possible solutions which can simultaneously address the need, and fit the application.

It is only after a number of workshops, meetings, underground visits, and discussion forums that this can be achieved and the solution can be designed and implemented. In short, discussion, collaboration, and partnership are necessary to follow this process, and these values need to be developed as the journey proceeds.

ABOVE Mike Andrews, business line manager: Automation, Sandvik

What technology does your company offer mines in their mechanisation/ automation plans?

Adoption of, and adaptation, to fully autonomous mining is often considered to be daunting for many mine operators. This is primarily due to the changes required to successfully implement autonomous mining: technology changes, mining method and layout changes, and, very importantly, change management and acceptance from all stakeholders.

We’ve, therefore, developed our automation offering to provide various levels. This enables mine operators to test the value of automation within their mining environments, using introductory levels of automation, with minimal safety, productivity, and financial risks. Once satisfied and comfortable with the solutions, operators

in the spotlight

can then expand and evolve, allowing more tasks, activities, and processes to be automated in a stepped approach.

Sandvik offers the full spectrum of automation for surface and underground mining applications ranging from: • Sandvik Equipment Monitoring: Monitoring of equipment health, productivity, and utilisation data, which can be monitored and managed in real time.

• Sandvik Production Management: Management of individual mining tasks, dispatching of resources, real-time monitoring of task progress, and management of the mining process via centralised operations control rooms.

• AutoMine® Loading Lite: Single-loader with fully autonomous stope loading capabilities operated from a safer, remote location or a centralised control room.

• AutoMine® Loading and Hauling: Fully autonomous loading or hauling (fleet) with autonomous traffic management and task management.

• AutoMine® Surface Drilling: Including remote monitoring and reporting, 3D visualisation, production management, video and/or 3D-assisted remote control of selected equipment, and full fleet automation.

What enabling technology (IT & comms) and infrastructure is needed to mechanise/automate a mine?

IT and communications infrastructure requirements depend on the mining application, the degree of automation within a given mine, and the need for semi-realtime or real-time feedback. As discussed above, the various levels of automation offered by Sandvik allow mines to gradually increase the quality and quantity of communications infrastructure required.

For the simpler levels of automation, such as remote monitoring, we would suggest that upload hubs (or access points) are only required at strategic locations in the mine, such as at mine tipping points, refuel bays, and workshops. This enables information to be uploaded to the central system when the equipment passes these locations, since the information is not required in real time.

For the intermediate levels of automation (Sandvik AutoMine® Loading Lite), we recommend a mobile WLAN solution, which can be installed only in designated workplaces (e.g. stopes) and moved to other locations once work has been completed in the workplace. This allows for a more mobile, flexible, and

cost-effective solution. For the more complex levels of automation (e.g. fully autonomous fleets), Sandvik generally recommends comprehensive WLAN and Wi-Fi communications throughout all relevant workplaces.

This ensures real-time monitoring, management, and control at all times. As you can see, the offering we suggest to mining operators depends on their unique needs, the mining application, and their appetite for technology and innovation. Once this has been explored, we can then define the optimal solution, which can be expanded over time, once all are comfortable with the deliverables.

What type of personnel and training requirements are needed to mechanise/automate a mine?

Based on our experience in implementing a wide range of automation projects globally, we see change management as one of the primary training requirements to ensuring automation is a success. That is why we stress so heavily on this evolution approach at all levels of the organisation.

The need to partner and collaborate with our customers, explore their needs and requirements, understand their challenges and constraints, and jointly define a solution that addresses these is fundamental. This can only be achieved through in-depth time commitment and discussion. If this is achieved successfully, the rest tends to fall into place naturally.

There is, of course, the need for new technical, operator, and management skill sets to operate and manage autonomous mines. In order to train these stakeholders, Sandvik offers a range of training and coaching programmes. These are typically recommended before and during the implementation stages, to ensure that the necessary skills are available before the automation becomes operational.

We also offer benchmarking visits to other mining sites with similar automation applications, so that new customers can see what they will acquire before it is implemented. Training is offered at our automation test mine in Finland (so that mining operators can be trained on systems and technology before implemented on their sites) as well as on-going training on-site. Full automation support programmes are also available, in order to supply on-going technical support (remotely from our overseas factories or on-site) to our customers during the operation of the automation solutions.

What productivity and cost-efficiency benefits can be expected from mine mechanisation/ automation?

Productivity and cost benefits are very dependent on the level of automation, the mining application, and how well it is implemented. In certain cases, we have seen improvements in cost and productivity ranging from 50% to 100%, and more. The automation evolution approach we recommend will generally enable us to define and quantify the benefits on a case-by-case basis with each mining operator. This will be performed jointly between Sandvik and our customers so that there is transparency and deep-rooted understanding of the numbers and assumptions. This approach enables us and our customers to evaluate the cost-benefit relationship of each case and decide on the optimal solution.

One area that is vital to emphasise is the importance of safety. The key driver for implementing automation for the majority of operators is to optimise safety. Mine automation usually removes a large number of people from potentially dangerous operating areas of mines, thereby separating people from hazardous zones and reducing risk. Sandvik, and our customers alike, sees this as one of the key benefits of automation and the value of it cannot be emphasised enough.

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Economics, finance & risk

The criticality of

collaboration A recovery in commodity prices is not likely any time soon, and the focal point of any recovery in the mining sector will have to be predicated on innovations, healthy partnerships, and crosssectoral cooperation. Inside Mining examines the key points raised by Mike Teke, president of the SA Chamber of Mines (SACM), in his address at the 125th SACM AGM this year.

T

he World Bank’s Doing Business 2015 saw South Africa drop six places from the previous year. The report cited a slew of new regulations and government programmes that increase the cost of doing business and slow down the monetisation of productivity. Some argue that reducing regulations and removing inhibitory policies will encourage investment and job creation, with the resulting broadening tax pool being the appropriate origin of funding for government’s ambitious social agendas.

In his address, Teke acknowledged this challenging environment, characterised by depressed commodity prices, escalating costs, and electricity supply challenges; he gave equal attention to the continued uncertainty regarding certain mining and transformation laws. “It is our considered view that unblocking constraints and allowing the mining sector to achieve its potential is key for South Africa achieving growth and development targets set in the NDP,” he noted.

Teke paid homage to those who suffered as a result of the Marikana tragedy, and suggested the industry has “learned a lot from the events of Marikana, and we will doubtless find more of value to better equip us to carry out our work in a manner that will guarantee the sustainability of the industry, as well as the well-being of all our employees and

10 Ins i de Mi n i n g 0 6 | 2 0 1 5

other stakeholders.”This approach speaks to both sides of the current challenge faced by labour, the mines themselves, and government.

Rising costs Turning to the rising costs, Teke’s key concern is that of the upward pressure on electricity prices, and the negative impact this will have on the viability of gold and platinum mines. “The Nersa-approved (National Energy Regulator) 12% increase in the electricity price, in 2015, will add an additional R2 billion in costs on to the platinum and gold sectors. The additional 13% increase requested by Eskom will double this,” he explained. “Rapid increases in these costs are already affecting the viability of many gold and platinum mines, with 31% of gold mines and nearly 40% of platinum mines making losses at current prices.” With an associated cut-back on capex, further restructuring seems essential to remain viable.

Mike Teke, Chamber of Mines president

than it is. This potential can only be realised if the minerals can be mined in a safe, environmentally friendly, sustainable, transformative, and profitable manner.

“To realise this potential requires significant investment. To get this investment, we, as a country, have to create a stable, competitive, and predictable policy, legislative, and operating environment. We believe that we have a number of the key pillars of a successful mining environment,”

This potential can only be realised if the minerals can be mined in a safe, environmentally friendly, sustainable, transformative, and profitable manner

Destination South Africa Beyond this tough environment are other factors related to attracting local and international investment. “The key question is whether South Africa is still a preferred mining investment destination globally and in Africa, or whether other jurisdictions are taking preference,” said Teke.

With its vast mineral resources, South Africa should be reaping so much more

said Teke.

But there are other problematic areas including uncertainty in some areas of our mineral and transformation laws, potential new taxes (carbon tax), the push for mining companies to subsidise manufacturing, infrastructure bottlenecks, and skills challenges. Most mining professionals see partnerships as the solution to

“Applying both a carbon tax and a carbon budget will mean that South Africa is the only developing country to do so and this will prejudice the survival and competitiveness of the carbon-intensive mining industry.” Mike Teke, Chamber of Mines president these challenges. Lonmin, for example, believes that mines should collaborate in the development of their social labour plans to solve infrastructure issues and service delivery to their affected communities, while the presidency is looking to apply Operation Phakisa – a project designed to set targets for, and monitor progress on, addressing national key priority challenges, adapted from Malaysia’s Big Fast Results approach – to the mining sector.

Calling for a renewed approach, Teke explained: “We have to work together in a more collaborative, problem-solving partnership that places the achievement of the 2030 NDP targets as a key vision; we are excited about the president’s announcement of the application of Phakisa to the mining sector.

It is critically important to get Phakisa right, along with the cooperation and collaboration it will require, and develop strategic and tactical plans to resolve the constraints facing the sector.”

Seizing the day Given this indication from the public sector that the doors of collaboration are opening, Teke emphasised that the industry has a rare, though urgent, opportunity to create policy and address regulatory uncertainty. “As an industry, we need to take a bold step and address regulatory uncertainty. We urge government to deal with the MPRDA Amendment Bill expeditiously and ensure the outcome supports a vibrant and competitive mining sector,” he said.“Resolving these types of issues will help restore confidence in our industry and improve our investment attractiveness as a country,” he continued.

“We need to get certainty on the Mining Charter so that we can continue with the transformation programme.

The agreed pursuit of a declaratory order is key to creating certainty in the interpretation of the ownership element of the charter. We urgently need to deal with setting new charter obligations.” It is only in dealing with these regulatory

imperatives that the industry can create certainty for the sector and enhance its investment competitiveness.

Bad time for carbon tax Teke pulled no punches when addressing the timing of the proposed carbon tax: “A key challenge is the absurdity of going ahead with introducing a carbon tax and carbon budget, when South Africa’s existing carbon trajectory is even lower than government’s commitment made in Copenhagen, in 2009, and when electricity prices have increased at a rate that already discourages demand,” he stated.

“Applying both a carbon tax and a carbon budget will mean that South Africa is the only developing country to do so, and this will prejudice the survival and competitiveness of the carbon-intensive mining industry.”

The SACM is of the view that the carbon tax should not be introduced in 2016, and that the focus should be on carbon budgeting and other instruments that do not impair the competitiveness of the mining sector.

Putting South Africa first “We are just about to begin with wage negotiations in gold and coal. These are testing times for both employers and organised labour,” noted Teke, adding that restructuring may lead to potential retrenchments. Calling for high-level pragmatism during the wage negotiations, both sides of the table should aim to protect the viability of their industries and the long-term sustainability thereof and their jobs. Teke concluded the address by challenging the perception that the mining industry in South Africa is fading: “The mining sector is definitely a ‘sunrise’ industry, though we face very challenging headwinds in the short term.

I call on the leadership of all stakeholders to work together to help manage the short-term challenges and position this sector to realise its vast potential in the years ahead.”

I n s i d e M in in g 0 6 | 2 0 1 5 11

Economics, finance & risk

diamonds Industry-shaping trends Eight trends are influencing the diamond industry at present, and will continue to do so for the foreseeable future. Looking across the industry’s value chain, these influences should be avoided or exploited – whichever is applicable.

By Mckinsey & co.

W

ithin the global context, and the volatilities therein, scenarios can change in ways that influence industry-shaping trends in either a positive or negative way. The most significant influencers will be the United States’ ability to effectively manage its long-term debt, whether China can maintain its growth rate – given the dangers posed by its debt position – and whether Africa can rise and turn itself into the new economic powerhouse off the back of a growing middle class.

On the retail side, marketing to maintain the allure of diamonds will be critical to the success of the industry. Even so, these eight trends, seven of which were identified by Stewart Goodman, Martin Bratt, and Leonie Brantberg in McKinsey & Company’s report ‘Perspectives on the diamond industry’, will dominate the industry for the foreseeable future, all things being equal. The report, says, amongst other things:

Plateauing levels of production for the next 10 years I n 2013, global rough diamond production amounted to over 136 million carats. Given the lack of recent economically viable

12 Ins i de Mi n i n g 0 6 | 2 0 1 5

discoveries, rough production is likely to remain relatively constant over the next ten years. Post 2025, when a number of mines are scheduled to go out of production, production will start to decline.

Pressure from producing countries

to extract more value

cross the world, resource-driven counA tries are keen to extract more value from their natural resources, either through increased taxes and royalties, or through a strengthened push to increase their share of added value. We expect this pressure to continue, particularly in major diamond-producing countries in southern Africa (including Botswana, Namibia and South Africa), given their relatively low levels of economic diversification.

Increase in mining costs ew diamond deposits are found deeper N underground and in less accessible areas.

It is, therefore, more complex and expensive to extract them. Thus, we expect mining costs to continue to rise across both capex and opex. Over the last ten years, the capital intensity of new projects has risen threefold across most minerals, and critical input factors, such as labour and energy costs, have also grown rapidly.

We expect cost increases in the future to outpace inflation, leading to rising costs per carat.

Shift in demand to emerging markets Strong economic growth in developing markets continues to create a wealthy ‘new middle class’, which will be an important driver of demand for diamonds.

All of the five equity analysts we interviewed for this research identified the middle classes in Asia as key drivers of future demand. They specified India and, especially, China as particularly important to demand growth. McKinsey’s own estimates indicate that, by 2020, ‘mainstream’ Chinese consumers – households with annual disposable income between USD 16 000 and 34 000 – will make up 51% of urban households (from 6% in 2010), and affluent households 6% (from 2% in 2010).

Changing consumer preferences Research undertaken for our ‘Jewelry 2020 – On the Heels of Apparel’ report indicates that consumers increasingly prefer branded jewellery. This is also true for high-end diamond jewellery. Brands reduce consumers’ risk of making the

Economics, finance & risk

‘wrong’ purchasing choice, and Graph 1 World diamond production share of major assortments or to compare availhelp them express their person- companies in 2012 (Source: McKinsey & Co.) able production across different ality by way of association. Only mining companies.

20% of today’s jewellery market is driven by brands. All the sen Improvement of technical ior jewellery executives we incapabilities in terviewed for the report agreed synthetic gems that brands will claim a higher Synthetic gem companies, share of the market by 2020, and the technology they use, although their views differed on are becoming increasingly how exactly that would happen. sophisticated. If synthetic stones Most of them expect the brandleak into the diamond value ed segment to account for 30 to chain, without being properly 40 per cent of the total market labelled as synthetic, they may Graph 2 Per carat diamond price from 1960 to 2014 (in US in 2020. pose a risk to the industry dollars) (Source: McKinsey & Co.) Four factors underlie this by undermining consumer trend. First, our research sugconfidence in the authenticity of gested ‘new-money’ consumers what they are buying. However, (who are less likely than the detection technology used to ‘old-money’ wealthy to have identify synthetics has, so far, inherited jewellery) will likely kept up with the technology used seek branded jewellery to show to produce them. their wealth. Second, emergSynthetic diamonds are cating market consumers trust egorised as either high-presbrands more. sure high-temperature (HPHT) In our research, 80% of inor chemical vapour deposition terviewees quoted established (CVD) diamonds, depending on brands inspiring trust and prohow they were made, and are viding a lifestyle benefit as a Graph 3 Global rough diamond demand from 2005 to 2020 virtually identical to natural (in billion US dollars) (Source: McKinsey & Co.) purchasing factor. Third, interdiamonds. The differences are viewers highlighted the focus only apparent when viewed by a of many young customers on trained grader in a gemological brands as a means of self-exlaboratory. In researching what pression and self-realisation. all the fashionistas had to say Finally, luxury brands playabout 2015, it became apparent ing in neighbouring categories, that yellow diamonds will be, by such as Louis Vuitton, Hermès, far, the most sought-after fancy and Dior, are introducing jewcolour for the foreseeable future, ellery collections or expanding simply because so many celebritheir assortment, especially in ties have been wearing them rethe higher-end segment. For dicently. Green and blue diamonds amond mining companies, the will also boost demand, because building consumer demand for the prodimpact of this is mixed. On one hand, it these shades go well with the vintage ring uct, which is the key to maintaining the increases the likelihood that value will be styles rising in popularity. position of diamond jewellery, relative to captured by those who control the brand, Demand for pink diamonds, a current other luxury goods categories. as opposed to those who control the prodfad, will start slowing down this year. uct (consumers will want ‘a Tiffany ring’ South African rather than ‘a diamond ring’). But, on the bank Investec Increases in transparency and other hand, large-scale consumer brands gives a bright vertical integration have the means and ability to invest in outlook for diaDigitalisation of the supply chain will

monds in 2015. enable a larger client base to access the However, other diamond market. A notable example is commentators the development of online open auc“When buying loose are not so positions, which allow new players, not just diamonds, it is tive and feel the the traditional select set of diamond year may be a bit buyers, to access rough diamonds.

New imperative to always quiet. Only time technologies will also enable diamond ask whether the will tell. jewellery manufacturers to be increasingly selective regarding the production diamond is natural they acquire. For instance, it will likely ABOVE Stewart Goodman, McKinsey or synthetic.” become easier for them to ask for specific & Company In sid e M in in g 0 6 | 2015 13

commodity: diamonds

Diamond exploration

New and greater

opportunities

Australian scientists have unveiled a groundbreaking study that shows micaamphibole-rutile-ilmenite-diopside (MARID) veined peridotitic mantle represents a suitable source for orangeite melts. By Andrea Giuliani et al.

A

n Australian research team comprising Andrea Giuliani, David Phillips, Jon Woodhead, Vadim Kamenetsky, Marco Fiorentini, Roland Maas, Ashton Soltys, and Richard Armstrong published their groundbreaking research into diamond exploration in Nature Communications recently. The crux of their research is that the genetic relationship between mantle MARID assemblages and orangeite melts in South Africa can be extended to other continents.

Kimberlites and orangeites (previously named Group-II kimberlites) are small-volume igneous rocks occurring in diatremes, sills, and dykes. Evidence

14 Ins i de Mi n i n g 0 6 | 2 0 1 5

suggests that orangeites were formed from lava produced by massive volcanic eruptions several tens of millions of years ago. Until now, the common belief was that diamonds were formed about 990 million years ago.

Kimberlites and orangeites are the main hosts for diamonds, and are of scientific importance because they contain fragments of entrained mantle and crustal rocks, thus providing key information about the subcontinental lithosphere.

It was previously believed that orangeites were common only to South Africa. However, this research shows that similar rocks have also been identified in Australia, India, Russia, and Finland. In

ABOVE Diamond study reveals key information about the earth

this regard, the research proposes that orangeites from the Kaapvaal Craton (Southern Africa) may be local variants of global lamproite-like ultrapotassic magmatism, with all these melts derived from metasomatised lithospheric mantle. Like kimberlites, orangeites occur as small pipes (<2 km in diameter), sills, and dykes, and are hybrid rocks consisting of mantle-derived xenoliths (that is, rocks fragments) and xenocrysts (including diamonds) set in a matrix of magmatic origin. Orangeites are ultrapotassic, H2O- and CO2-rich rocks hosting

minerals such as phlogopite, olivine, calcite, and apatite.

The major and trace elements, and isotopic compositions of orangeites, resemble those of intensely metasomatised mantle of the type represented by MARID xenoliths. New data for two MARID xenoliths, from the Bultfontein kimberlite (Kimberley, South Africa), show that MARID-veined mantle has mineralogical (carbonate-apatite) and geochemical (Sr-Nd-Hf-O isotopes) characteristics compatible with orangeite melt generation from a MARID-rich source. This interpretation is supported by U-Pb zircon ages in MARID xenoliths from the Kimberley kimberlites, which confirm MARID rock formation before orangeite magmatism in the area. Rough on the outside, these rocks contain not only treasured diamonds but also tiny fragments of mantle and crustal rocks. By using highly sophisticated geochemical

Realising possibilities...

FIGURE 1 Schematic map of Southern Africa showing the location of the Kimberley area. The estimated boundaries of the Kaapvaal Craton, the position of major kimberlite and orangeite intrusions around Kimberley, and of major outcrops of Karoo igneous rocks are also shown. Scale bar: 500 km

and isotopic analytical techniques, the scientists were able to link those fragments to the source of the orangeites, deep in the interior of the planet. “We found strong evidence that orangeites are sourced from MARID mantle, which, up until recently, had only been recognised in South Africa. However, ongoing studies suggest that MARID mantle may occur in other continents, including Australia,” said leading author Prof Fiorentini, from the University of Western Australia. MARID rocks have been transported from the lithospheric mantle to the Earth’s surface by kimberlite, orangeite, and lamprophyre magmas from various localities worldwide.

MARID rocks represent an extreme example of mantle metasomatism because of their exceptional enrichment in alkalis, LREE, HFSE (e.g. Ti, Zr, Nb), and volatile species – primarily H2O. For this reason, MARID rocks have been frequently invoked to account for the origin of alkali-rich mafic-ultramafic magmas, with the notable exception of orangeites. Sweeney et al. noted that the bulk major element composition of MARID rocks could be obtained by subtracting the composition of olivine and carbonates from a bulk orangeite composition. In addition, the Sr-Nd isotopic composition of several MARID rocks overlaps with the field defined by orangeites. It is, therefore, possible that a MARID-veined peridotitic mantle could represent the source of orangeite melts. To test this hypothesis, the team examined the composition of primary mineral inclusions

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in MARID phases and determined the mineral major and trace element concentrations clinopyroxene Sr-Nd-Hf isotope ratios, and zircon U-Pb-Hf-O isotopic compositions, for two MARID samples from the Bultfontein kimberlite (Figure 1). The Kimberley area is unique, because it hosts kimberlites that were emplaced after the orangeites of the Barkly West-Boshof district, and the Kimberley kimberlites host a variety of metasomatised mantle xenoliths, which have been extensively studied.

Thus, mantle xenoliths entrained by the Bultfontein kimberlite can be considered representative of the same mantle lithosphere that produced the Barkly West-Boshof orangeites.

The study reveals that MARID minerals contain carbonate-rich primary inclusions and have Hf isotopic compositions similar to Southern African orangeites. Some MARID zircons show U-Pb ages that predate the emplacement of orangeites and δ180 values above the mantle range. The results, combined with existing data, confirm that a MARID-veined peridotitic mantle represents a suitable source for orangeite melts.

Results MARID xenolith samples XM1/331 and BLFX-3 were collected from the Bultfontein dumps, which contain waste material predominantly from mining of the Bultfontein kimberlite. The Bultfontein kimberlite is part of the Kimberley cluster of kimberlites (Figure 1), which have been classified as archetypal kimberlites, based on their mineralogy and Sr-Nd isotopic signature.

The Kimberley kimberlites were emplaced between 81 and 90 million years ago, based on Rb-Sr phlogopite and U-Pb perovskite geochronology MARID xenoliths are relatively common in the Kimberley kimberlites. The two samples studied here exhibit coarse-grained foliated textures, with compositional banding related to the preferential concentrations of K-richterite and phlogopite in discrete layers (Figure 3), a common feature of MARID rocks.

Clinopyroxene, in textural equilibrium with phlogopite and K-richterite, occurs in sample XM1/331 but is absent in sample BLFX-3 – again this is not unusual for MARID samples. Oxide minerals, including rutile in sample XM1/331 and ilmenite in sample BLFX3, are widespread and account for up

16 Ins i de Mi n i n g 0 6 | 2 0 1 5

FIGURE 2 Ages of recent magmatic and mantle metasomatic events in the Kimberley area

to 5% of the xenolith volumes. Zircon grains are locally abundant in sample XM1/331, where they occur as isolated grains or clusters of grains included in, or interstitial to, K-richterite and rutile (Figure 3). K-richterite inclusions are frequently observed in zircons (Figure 3d). No zircons were observed in sample BLFX-3.

Pervasive carbonate-rich veins traverse both samples, a feature that is common to many other documented MARID xenoliths. MARID minerals in contact with these veins occasionally display thin (<10 µm) overgrowths and reaction rims, including clinopyroxene on K-richterite and baddeleyte, plus zirconolite rimming zircon (Figure 3d). The formation of these veins is attributed to reaction

with late-stage fluids from the entraining kimberlite magma. The research concludes that a MARID-veined peridotitic mantle represents the best candidate for the source of orangeite magmas. MARID rocks, and rocks produced by metasomatised lithospheric mantle magmas with features similar to orangeites, have been identified in localities worldwide.

It is, therefore, likely that the genetic relationship the team established between mantle MARID assemblages and orangeite melts in South Africa can be extended to other continents.

Reference: ‘Did diamond-bearing orangeites originate from MARID-veined peridotites in the lithosphericmantle?’, Andrea Giuliani et al., April 2015, www.nature.com

FIGURE 3 Images of zircon grains in MARID sample XM1/331. Optical photomicrograph of cluster of zircon (zrc) grains interstitial to K-richterite (kric) ((a) scale bar: 0.5 mm) and backscattered electron (BSE) SEM images of zircon grains included in K-richterite (b,d) and rutile (rt) (c). In (d), note the K-richterite inclusion in zircon, which is rimmed by zirconolite (zrcl)

commodity: diamonds

A world-class operation Every now and again, you come across a real gem of a mine that isn’t just about the commodity, but rather the entire mine, and the manner in which it is managed and operated. Petra’s Finsch diamond mine is such a mine. By Tony Stone

T

he Finsch diamond mine is pure synergy, a team effort between the mine, Sandvik – its primary mechanisation and automation provider – and other state-of-the-art technology service providers – such as Schneider Electric and Bentley – in an integrated system that literally runs like clockwork. Located 165 km north-west of Kimberley, in the Northern Cape, the mine is South Africa’s second largest diamond mine by production, after De Beers’ Venetia diamond mine.

With mine safety as the number one priority, Luctor Roode, general manager at Finsch mine, is a stickler for safety. Looking at Finsch’s safety record, it’s quite impressive. ISO 14001:2015 and OHSAS 18001:2015 accredited, its trophy cabinet is testimony to this, as is its November 2014 Northern Cape Mine Managers Association award for underground safety. Finsch is a

major resource, with 51.3 Mcts, including 28.0 Mcts in reserves and 2.0 Mcts in tailings. Its innovative infrastructure, modern plant, and quality management process provide the framework for its excellent, multi-award winning safety and environmental record, as well as its strong social responsibility programme.

The mine’s block caving and sub-level caving mining methods achieved a high-volume, low-cost 2014 production of 1.89 Mctpa.

Expansion plans will see a run-of-mine production increase to 2.0 Mctpa, from the 2018 fiscal year.

Surface to underground Mining at Finsch began on a small scale, after Allister Fincham and William Schwabel, two prospectors looking for asbestos, stumbled upon the find in 1960. When De Beers took over, in October 1964, they mined the 118 million year old volcanic pipe as an

TOP Finsch diamond mine ABOVE LEFT Luctor Roode, general manager at Finsch mine ABOVE RIGHT Pieter Boshoff, technical services manager at Finsch mine

open pit operation. This went on until September 1990, when this mining method was terminated, at which point the pit had a surface area of 55 ha and a depth of 423 m. From then onwards, the mine’s operations moved underground.

This is where things get interesting. Two methods of underground mining are being used at Finsch today – block caving and sub-level caving, in a mechanised and automated operation, explains In sid e M in in g 0 6 | 2015 17

commodity: diamonds

FIGURE 1 The geological model of the Finsch pipe

FIGURE 2 A cross section of the mine

Pieter Boshoff, technical services manager at the mine.

Operations centre

Geology To contextualise these mining methods, an understanding of Finsch’s geology is necessary. A classic diamondiferous kimberlite pipe, it is hosted by banded ironstones at the surface and, beneath that, dolomites and limestones of the Griqualand West Sequence of the Transvaal Supergroup. The pipe, originally 17.9 ha on the surface, is a group II kimberlite intrusion, consisting of weathered kimberlite (yellow ground) to a depth of around 100 m with unweathered material (blue ground) beneath that.

The main pipe tapers to 3.7 ha, and the precursor to 1.5 ha, at 880m. There are a total of eight different kimberlite facies, each with unique characteristics and different grades. Of these, two facies (F1 and F8) make up the majority of the main pipe.

Grade quality increases with depth, with a concomitant decrease in waste dilution.

BELOW Finsch’s control room

In moving underground, with the initial development of Block 4 as a mechanised and automated mining operation, and to maximise production efficiencies, the creation of a purpose-built operations centre was necessary. Also, and not forgetting that Finsch’s objective was to develop a technologically advanced mining operation, an intuitive operator interface, with simplified configuration for ease of maintenance and operation, was an absolute must. After a careful selection process to identify a SCADA solution that would provide the necessary high operability and scalability, as well as superior connectivity, Schneider’s CitectSCADA’s easy configuration tools and user-friendly screens were selected, and they were implemented without incurring delays.

For example, the advanced technology, especially in the use of ‘blown fibre’ – ultra-lightweight single bundle optic fibres passed through preinstalled tubes using only airflow – exemplifies the sophistication of this installation. In addition, this

particular type of fibre optics allows expansion without disrupting operations.

And, of key importance, CitectSCADA’s built-in redundancy and system stability were key factors in the purchase decision. Ensuring safety and reliability for the mine’s operations, the CitectSCADA system has dual redundant server pairs.

The system is used to monitor and control processes throughout the mining operation, including rock breaking and ore management. Sandvik's system, then, monitors and controls the access control, production control, dispatch, and onboard CCTV to deliver a total, low-risk solution that dramatically minimises downtime, lowers life-cycle costs, and provides crucial information in real time. A high-capacity (1 GB/second) Ethernet LAN handles the vast flow of data within the operations.

Four 62-inch plasma screens provide an overview of the production status and progress. Two are used for the autonomous operation, while the other two are used for the other mine operations. A fifth screen provides real-time coverage of the autonomous operations underground. In planning the centre, one of the primary risks identified was the possibility of production downtime. This was, and is, avoided with the support of a professional team of service experts. It’s their number one priority. For the mine, reliability and performance are non-negotiable.

Geospatial data system Bentley Systems were contracted to develop an integrated geospatial data management system to better enable Finsch to manage their geospatial data, which is stored in multiple databases across the five departments, previously functioning

18 Ins i de Mi n i n g 0 6 | 2 0 1 5

commodity: diamonds

in isolation. Data redundancy is now a thing of the past. On top of this, the mine also co-manages the mining town of Lime Acres, for which the GIS-based system captures data and bills residents for water and electricity usage. Survey and plan data are captured and digitised. The mapping feature digitally represents the mining lifecycle, town, and residential layout. The publishing feature makes the geospatial mining and town information accessible to the whole mining group. For billings, the database interrogates the human resources system and automatically sends invoices to residents.

Block caving Moving underground, block caving is a hard rock mining method that undermines an ore body, allowing it to progressively collapse under its own weight. As a mining method, it is a safe and proven method, which provides access to higher volumes of ore than other methods. So, how does it work?

With mechanisation and automation in mind, block cave mining involves an elaborate, thoughtful, and practically designed pre-construction process. First, access and ventilation shafts must be sunk to a level below the ore. In this instance, Finsch’s main shaft is down to its current depth of 825 m. After this, two rim tunnels circling the pipe are developed; the top rim tunnel is used for the ‘undercut’ layer, and the bottom for the ‘production’ layer.

Finsch was quite smart in its design, and developed a service tunnel, connected to the spiral decline tunnel, with oil bays, stores, service bays, wash bays, and offices off to the one side of the haulage rim tunnel. The service tunnel is linked, FIGURE 3 This diagram illustrates the block caving method

via connecting tunnels, to the rim tunnel.

A series of horizontal tunnels, known as haulage tunnels, running from one side of the production rim tunnel to the other, are excavated using the traditional drill and blast method, each with a slight rise in the middle to prevent water accumulation.

The small quantities of water run-off into the haulage tunnels are handled by due processes. Between, and connecting, the haulage tunnels, a series of drawpoints are excavated breaking out at an angle to accommodate the LHDs (load, haul, dump).

Within each connecting drawpoint tunnel, a funnel-like cavity or drawbell is drilled and blasted upward, beneath the undercut level. The mouths of these drawbells abut one another, forming a continuous plane of funnel mouths where they contact the undercut. Once a sufficiently large footprint of drawpoints, drawbells, and undercut is constructed, the main ore body is ready to commence with the process of caving, which will self-propagate as extraction continues. Following the undercut blasting, the overlaying ore collapses and funnels through into the drawbells, over a period of time, which then allows the ground to cave. Caving will continue as long as ore is extracted from the drawpoints. At this stage, it is critical that the drawpoint control plan is complied with by the LH410 LHD operators.

Sandvik has developed this drawpoint control plan, which is communicated via Wi-Fi network to a screen in the LHD. This ensures that the ore is extracted from the cave in a controlled manner. The loaders then transfer the broken ore to an ore pass system that then feeds an automated Sandvik TH550 truck loop, which accommodates up to nine trucks at any one time.

Finsch’s objective is to extend its life of mine to sustain its current production profile and increase run-of-mine throughput

ABOVE Deon Stander, from the technical training section at Finsch diamond mine, demonstrating the Res-Q-Pack

to 3.5 Mtpa, by commencing the extraction of Block 5 through the sub-level caving (SLC) mining method. Production is currently taking place in Block 4, at 630 m, while the development of the SLC is taking place between 700 m and 780 m. A dedicated conveyor for ore handling – to transfer SLC ore to existing infrastructure at 650 m – will be ready in the 2016 fiscal year.

Once Block 4 has been fully mined, it will be decommissioned, similar to upper historic levels. First production from Block 5’s SLC will take place later this year, with production ramping up to 3.5 Mtpa by 2018.

Sub-level caving Tunnels, or drifts, up to 200 m long, are drill and blasted through the orebody.

Walls and roofs are reinforced with several support elements, which include roof bolts, welded mesh, and spray-on concrete.

Once the production drifts are ready, a set of holes, up to 34 m deep, are drilled

A model of the construction of a block cave set-up

In sid e M in in g 0 6 | 2015 19

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commodity: diamonds

upwards through the orebody in a semi-circular or fan-shaped pattern. Each fan cut or ring blast consists of a set of 14 drill holes, and each set is 2 m apart. In a 200 m long drift, about 100 fan cuts are drilled, with fan cut 100 closest to the haulage rim tunnel. The drift rings are then blasted and the liberated ore is loaded by LHDs in a sequence from 1 to 100, and in sequence with adjacent and underlying or overlying levels. Ore is taken to tip points, where it is transferred through ore passes to a jaw crusher, situated in the host rock close to the ore body. Large boulders of ore are either reduced in size using explosives, mechanical breakers, or moved to a holding point for later secondary breaking.

The performance of the SLC is highly dependent on the extraction sequencing and the discipline in following the sequencing of the drill and blast process and, then, the draw control. Phase 1 of the SLC development â&#x20AC;&#x201C; the rim tunnel â&#x20AC;&#x201C; is complete. Tunnelling through the ore body is in progress, contributing undiluted ore. Excavation of

1 400 m, out of the 1 600 m of conveyor tunnels, has been completed. Civil work and structural installation has commenced on the conveyor belt system, and the crusher excavation is well advanced. First production is planned during 2015, with a ramp-up, over four years, achieving full production by 2018.

1

Wrapping up If anything, the Finsch mine is an example of modern mining sophistication. It is a case study that exemplifies the complete change in culture that is required to mechanise and automate a mine, but it is one that has transformed the entire Finsch mine into an integrated, highly productive operation. It has and will continue to deliver excellence.

1

Sandvik TH550 haul truck. These A machines are fully automated

2

T unnels are reinforced with bolts, mesh and spray-on concrete

3

A Sandvik LHD (loader, hauler, dumper)

2

3

In sid e M in in g 0 6 | 2015 21

commodity: diamonds

Modernisation reaps rewards

The rehabilitation and modernisation of the Lace diamond mine near Kroonstad, in the Free State, is progressing well. Inside Mining speaks to Paul Loudon, DiamondCorp CEO, about the mine’s progress.

T

o recap, the Lace diamond mine was first mined between 1901 and 1931, with some 4.5 million tonnes of rock extracted down to a level of about 240 m below surface. Approximately 750 000 carats were recovered during this period, at an average grade of 16 carats per hundred tonnes.

The two main types of kimberlite at Lace are an upper-level volcanoclastic kimberlite (VK), at an average grade of 24 carats per hundred tonnes, and a deeper coherent kimberlite facies (CK), at an average grade of around 55 carats per hundred tonnes.

CK becomes volumetrically dominant at depth, which confirms the old records that show higher grades in the deeper workings.

A 1.2 million tonne per annum diamond recovery plant, which has the capacity to treat ore for the over-25-year expected mine life, was built in 2008. In 2011, the company completed a 4.5 m x 4.5 m decline to the 240 m level; an old vertical shaft to the 350 m level is used for ventilation.

Along with white diamonds of above-average quality, historically, Lace is known for its fancy pinks and purples, which have become a signature gem of this mine.

While, historically, the bulk of Lace's value curve has been in the 1 carat to 4 carat range, the pipe has produced a number of

22 Ins i de Mi n i n g 0 6 | 2 0 1 5

large stones, up to 122 carats. More than 80% of the diamonds are of gem quality.

The big news, of course, is the unearthing of a 19.83 carat diamond, the largest stone yet recovered from its underground development at the mine. The diamond was found during the current work to develop the high-grade Upper K4 (UK4) block. In noting the find, Loudon said, “While the mine has produced diamonds of up to 100 carats in size in the past, this discovery was opportune, given that it was just starting to process its first underground kimberlite.”

Recent underground development In the three months leading up to 31 March 2015, implementation of the revised development schedule and budget continued, with the specific aim of bringing forward the ramp-up of commercial production from the mine’s underground operations by four months. The original schedule was the second half of 2015.

Tunnel development costs, to date, average R38 961/m, against a budget of R37 000/m. This was reduced from R40 764/m, in Q4 2014. The higher-than-budget costs are a result of increased dump truck breakdown and repair costs, which have been high due to the long haul distances from the underground UK4 block development

TOP Lace diamond mine’s processing plant ABOVE Paul Loudon, CEO, DiamondCorp

levels to surface. For this reason, completion of the tunnels and an underground loading chamber, required for commissioning the new underground-to-surface conveyor belt system, is the priority development activity currently underway. The conveyor belt is 91% fabricated, on-site, and 51% installed, with the installation contractor now completing the fourth of five transfer arrangements required to link the belt to surface. The conveyor belt commissioning schedule has moved by several weeks into July, but without impacting the critical path as it will still be commissioned

commodity: diamonds

ahead of the mining ramp-up from the UK4 block. The conveyor belt will handle both kimberlite and development waste, and has the capacity to bring 400 tonnes per hour to surface (an average of 8 000 tonnes per day), compared with a maximum of 975 tonnes per day hauled by the mine’s five dump trucks.

Load and haul costs are expected to be around R6 200/m using the conveyor, compared with R13 000/m using the dump trucks. International oil price drops have had little impact on diesel costs in rand terms. The mine continues to be unaffected by Eskom loadshedding.

Resource definition drilling A total of 3 321 m of resource definition drilling of the UK4 block has been completed, providing the volume data required for a forthcoming resource statement update. The drilling has delineated 2.6 million tonnes of high-grade K4 kimberlite above the 370 m level to the new top of the model, at the 230 m level, an increase of more than 2 million tonnes over that contained in the original Lace geological model,

which topped at the 345 m level. This volume is significantly more than was initially expected. Processing of kimberlite from development tunnels in the UK4 block has commenced, with tonnage currently coming from lower-grade K6 kimberlite.

The plant is operating efficiently and diamond recoveries have included a 19.83 carat clear white gem – the largest gem diamond recovered from underground development so far. The recovery of this stone underlines the potential of Lace to produce larger gems, and will have a positive impact on the average carat value of diamonds recovered. Processing of kimberlite from development tunnels in the UK4 block is being monitored by MPH Consulting Limited as a controlled bulk test, with individual batches of approximately 1 000 tonnes being processed separately and augmented with representative microdiamond sampling. These results – combined with previous microdiamond analysis, which has predicted grades from the K4 unit of BELOW Part of Lace’s diamond recovery plant

at least 60 carats per hundred tonnes – will provide the grade data required for the resource statement update this year.

Subsequent valuation and sale of the recovered diamonds will provide the carat value required to complete the updated High-quality gem diamonds, 35 carat, 18 carat, and 15 carat stones recovered from dumps

Broad-based Black Economic Empowerment (BBBEE) SA operating subsidiary Lace Diamond Mines is owned 74% by DiamondCorp, 13% by Shanduka Resources, and 13% by Sphere Investments.Shanduka Resources is a subsidiary of Shanduka Group, a BBBEE company founded by Cyril Ramaphosa in 2001.

Sphere Investments is a black-controlled and -managed investment company founded by Itumeleng Kgaboesele and Pulane Kingston in 2003.

Lace Diamond Mines is a certified Level 4 contributor to BBBEE and fully compliant with the BBBEE objectives under the Mining Charter.

In sid e M in in g 0 6 | 2015 23

pipes, pumps & valves

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Main Benefits: • Reliability - tough, Atlas Copco quality • High performance - fast penetration rates give more metres per shift • Easy and quick positioning thanks to the extendable boom Atlas Copco South Africa Phone: +27 11 821 9000 Fax: +27 11 821 9202/9246 Innes Road, Jet Park, Boksburg, 1459 www.atlascopco.co.za

24 Ins i de Mi n i n g 0 5 | 2 0 1 5

commodity: diamonds

resource statement. The potential for significant volumes of additional high-grade kimberlite above the 370 m level was the catalyst for the UK4 mine plan. Mining of the UK4 block will extract 30 000 tonnes of kimberlite per month, by the long-hole open-stoping bottom-up method. The extraction will commence in the centre of K4 unit and stoping will then progress north and south simultaneously, until the contact with lower-grade K6 kimberlite is encountered.

A total of 1.6 million tonnes is planned to be extracted from the UK4 block, while the first block cave is developed, the majority of which will be high-grade K4 kimberlite.

The unmined balance of the UK4 tonnage will then fall into the first cave for extraction in the later years of the cave.

FIGURE 1 Geological model of the Lace resource

Plant and tailings re-treatment The companyâ&#x20AC;&#x2122;s metallurgical consultants have commenced preliminary test work on the potential for installing a high-volume optical and X-ray waste sorter ahead of the dense media separation plant.

Such a unit could remove large volumes of internal waste from the kimberlite before processing.

The K6 kimberlite contains up to 85% waste in places, and the higher-grade K4 kimberlite has up to 25% internal waste.

Installation of a waste sorter has the potential to significantly reduce plant water and electricity consumption, and could also allow the kimberlite to be processed faster than the currently planned 220 tonnes per hour. If the test work is successful, a unit could be installed before the mining ramp-up from the first block cave.

Tailings re-treatment processing stopped in September 2014. As tailings retreatment is a break-even proposition, there are currently no plans to resume processing until sufficient process water storage has been finalised. However, the mine currently has sufficient water in storage to meet all of its kimberlite processing requirements for 2015.

FIGURE 2 Geological model of the Lace block cave layout

BELOW Aerial view of the Lace diamond mine showing the tailings dump

Wrapping up In wrapping up, Loudon said, â&#x20AC;&#x153;Getting the conveyor belt up and running would also be a landmark for the mine. It will be a game changer because we will be able to pull over 8 000 tonnes a day, compared to less than 1 000 tonnes at present with trucks, while the cost per metre comes right down. Real savings of R6 800/m will be achieved.â&#x20AC;? All things being equal, the Lace diamond mine has a bright future.

In sid e M in in g 0 6 | 2015 25

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commodity: diamonds

A place of exceptional diamonds In the vast expanse of Botswana’s Kalahari Basin, on the northern edge, just south of the Makgadikgadi Pans National Park, and in one of the world’s richest diamond-bearingkimberlite areas, is the Karowe mine – a place of exceptional diamonds. By Tony Stone

L

ucara Diamond announced, on 20 April 2015, it they had recovered a 341.9 ct diamond at its Karowe mine. This follows on from a 239 ct diamond recovered at the same mine, in March 2013, and more exceptional diamonds before that, including extremely rare ‘blue’ diamonds.

The Karowe mine, in full production, is a hard-rock, open-pit mine planned to a depth of 324 m. The mine plan is based on probable reserves, to a depth of 324 m, of 33.1 mt, which contains an estimated 5.1 million cts. The indicated resource from surface to a depth of 400 m, of 48.07 mt, contains some 7.61 million cts and the inferred resource from 400 m to 750 m, of 21 mt, contains 3.04 million ct. In a corporate presentation, William Lamb, president and CEO of Lucara Diamond Corp, took a positive view of 2015 and, in his 2015 Q1 report, predicts: • 2015 revenues of $230 million to $240 million • diamond sales of between 400 000 cts to 420 000 cts • operating costs of $33 to $36 per tonne processed • capital expenditure of up to $20 million (plant optimisation project) • sustaining capital of up to $8.5 million (including $3 million for millrelining machine) • exploration budget of $7 million to $8 million (including purchase of bulk sample plant).

“As a resource, Karowe continues to deliver significant stones of greater than 10.8 cts, with 815 recovered during 2014, at an average of 29.1 cts per stone, and 153 so far in 2015, at an average of 27.7 cts per stone,” Lamb said. The Karowe mine has produced more than sixty-five stones greater than 100 cts, including nine stones greater than 200 carats.

Geology The Karowe mine is based on the AK6 kimberlite pipe. The region’s bedrock is covered by a thin veneer of wind-blown Kalahari sand and exposure is very poor.

Rocks close to the surface are often extensively calcretised and silcretised, due to prolonged exposure on a late tertiary erosion surface, which approximates to the present-day land surface. All kimberlite intrusions are of post-Karoo age.

The country rock at the Karowe mine is sub-outcropping flood basalt of the Stormberg Lava Group (approximately 130 m thick), which is underlain by a condensed sequence of upper Carboniferous to Triassic sedimentary rocks of the Karoo Supergroup (approximately 245 m thick).

The Karoo sequence overlies the granitic basement. AK6 is a roughly north-south elongate kimberlite body with a near-surface expression of ~3.3 ha and a maximum area of approximately 7 ha at ~120 m below surface.

The body comprises three geologically distinct, coalescing pipes that taper with depth. These pipes are referred to as the North Lobe, Centre Lobe, and South Lobe.

The AK6 kimberlite is an opaque, mineral-rich monticellite kimberlite, texturally classified primarily as fragmental volcaniclastic kimberlite with lesser macrocrystic hypabyssal facies kimberlite. The nature of Lucara Diamond Corp’s Karowe diamond mine situated in Botswana's Kalahari Basin

In sid e M in in g 0 6 | 2015 27

commodity: diamonds

â&#x20AC;&#x153;The recovery of the 341.9 ct stone is a significant milestone for us. It is now the largest diamond to have been recovered from the Orapa kimberlite field and definitely the largest that we have recovered so far.â&#x20AC;? William Lamb, president and CEO, Lucara Diamond Corp the kimberlite differs between each lobe, with distinctions apparent in the textural characteristics, the relative proportion of internal country-rock dilution, and the extent of weathering.

The South Lobe is considered to be distinctly different from the North and Centre lobes, which are similar to each other in terms of their geological characteristics. The North and Centre lobes exhibit internal textural complexity (reflected in apparent variations in the degree of fragmentation and proportions of country-rock xenoliths), whereas the bulk of the South Lobe is more massive and internally homogeneous.

The upper parts of all three lobes contain severely calcretised and silcretised rock.

Typically, this zone is approximately 10 m in thickness, but can be up to 20 m in places. Beneath the calcrete and silcrete, the kimberlite is highly weathered. The intensity of weathering decreases with depth, with fresh kimberlite generally intersected at about 70 m to 90 m below the present-day surface. A unit within the South Lobe has been found to be hard, and to produce a very large dense-media separation concentrate, primarily as a consequence of an abundance of fresh olivine in the kimberlite.

Treatment and recovery plant In 2010, DRA was contracted to provide a complete engineering, procurement, and construction management (EPCM) service for the design and construction of a diamond milling, dense-media separator (DMS), and recovery plant, with associated crushing, screening, and thickener systems.

The Karowe diamond plant was designed to process 2.5 mt of run-of-mine (ROM) kimberlite ore per annum with a single 200 tph DMS module.

The concentrate material from the DMS is subsequently treated through a 2.5 tph wet X-ray recovery plant for material reduction and diamond recovery. The process flow consists of drilled, blasted, loaded, and hauled pit ore transported to

28 Ins i de Mi n i n g 0 6 | 2 0 1 5

a primary crusher where FIGURE 1 Geological model of the Karowe resource after it is transported via conveyor belts to a single autogenous (AG) grinding mill. Any +35 mm mill product is crushed in a single pebble crusher and then recirculated to the AG mill, so called because of the self-grinding effect of the ore through a rotating drum, which throws larger rocks of ore in a cascading motion that causes impact breakage of larger rocks and compressive grinding of finer particles. Besides accomplishing the same size reduction Plant optimisation project work that normally takes multiple stagThe increase in the orebody hardness es of crushing, screening, and grinding has required several modifications to the methods, the AG mill also lends itself to comminution circuit, so that the process high-volume processing. The +1.5, 35 mm plant can maintain a throughput of 250 mill product exiting the AG mill is transt/h. The comminution circuit upgrade ported via conveyor to a DMS, with the comprises a new secondary gyratory DMS sinks sent to an X-ray recovery circrusher, a bleed circuit ahead of the AG cuit comprising a single-pass coarse X-ray grinding mill, new AG grinding mill discircuit and double-pass fines and middles charge grates, the installation of turbo X-ray circuit. pulp lifters in the AG grinding mill, and Any â&#x20AC;&#x201C;1.5 mm material is pumped to a the inclusion of a bleed screen after the de-grit circuit where, along with the DMS pebble crusher. tailings, these are sent to the tailings Karowe is also making history by bedump. The slimes are pumped to a thickcoming the first diamond mine to use ener and then to a tailings storage facility.

X-ray transmission (XRT) technology, FIGURE 2 The Tomra XRT

commodity: diamonds

which recognises and recovers diamonds through their specific atomic density.

Diamonds, with an atomic number of six, show up much lighter on an XRT image than silica-based gravels (silicon has an atomic number of 14). This diamond BELOW COO Paul Day at the viewpoint overlooking the pit

recovery technology can remove large quantities of gangue material, substantially increasing the ROM ore grade before any conventional processing takes place. XRT can be used for preconcentration, which can effectively upgrade the mill feed prior to more conventional physical upgrading and acid leaching. It is an alternative technology to dense-media separation.

Advantages include the relatively small footprint of the XRT sorting equipment, a reduction in energy consumption by as much as 15%, and a reduction in the amount of water used by three to four cubic meters per tonne of ore.â&#x20AC;&#x153;The overall objective for completing the plant optimisation project is to be able to process the harder high-yielding ore. It will allow the plant to maintain its 2.5 million tonnes per annum throughput. This is an opportunity for us, now that we better understand the resource so as to include large diamond recovery, which entails diamonds from 60 mm to 70 mm in size,â&#x20AC;?

Lamb said.

In sid e M in in g 0 6 | 2015 29

commodity: gems

Guidelines for gem mining Many landowners and small- and medium-scale mining entrepreneurs are attracted to the potential profits of the coloured gemstone market – but daunted by numerous regulations. By Rowena Hay, Paul Lee, and Dylan Blake

T

he Mineral and Petroleum Resources Development Act, No. 28 of 2002 (MPRDA), which governs mineral legislation in South Africa, came into effect on 1 May 2004. It effectively transferred ownership of privately held mineral rights to the state, enabling any third party to apply to the Department of Mineral Resources (DMR) for new-order prospecting rights or mining rights over previously privately-held mineral rights. Prior to the 2004 regulation, a surface landowner had rights to the minerals on his or her land.

Thereafter, any applicant who was not the surface owner was entitled to exploit the deposit by applying to the DMR and Department of Environmental Affairs (DEA) for the appropriate mine right or mine permit application. In effect, this shifted sub-surface ownership from the title deed holder to the state. It also meant that small-scale miners would have to undergo an extensive licence application process.

30 Ins i de Mi n i n g 0 6 | 2 0 1 5

Southern African trade The semi-precious mining sector in Southern Africa is one of the major contributors to the worldwide supply of coloured gemstones; equal only to other southern hemisphere countries like Australia and Brazil. The art of lapidary (cutting, polishing, and engraving gems) in South East Asia, and the extensive worldwide consumption of beads, jewellery, and urban jewellery (large polished blocks of stone decorating parks and buildings), has been a blessing for the South African trade in quartz, tiger’s eye, and jasper for several decades.

In order to exploit this resource, smallscale mining endeavours, mostly of a pit and trench style, have sprung up throughout the region.

They are generally driven by farmers or small business entrepreneurs who are often daunted by the prospect of the Environmental Management Plan/Programme (EMP) and Environmental Im-

pact Assessment (EIA) process required for the formal application to the DMR and DEA respectively.

Northern Cape geology Most of South Africa’s semi-precious wealth lies in a broad southwest to northeast-orientated band, which runs through the Northern Cape to the south of the Kalahari region. Geologically, this area mainly comprises the approximately 800 to 2 200 million-year-old Namaqua-Natal Metamorphic Province (NNMP). Intense deformation and temperatures altered large portions of the NNMP rocks – predominantly granites, gneisses and metamorphosed sedimentary rocks. This took place during a 1 000 to 1 400 million-yearold mountain-building event known to geologists as the Kibaran Orogeny. Hot fluids containing dissolved metals moved through the rock material and crystallised large, megacrystic (very coarse-grained) veins known as pegmatites during this

commodity: gems

(GIS) skills. This is in order to present the entire process in a concise and readable report for scrutiny by government organisations, interested and affected parties (IAPs), and potential investors. This is where consultants are able to offer efficient and affordable professional services.

Rehabilitation

1 mountain-building event. These abundant pegmatites contain many of the interesting and valuable semi-precious and precious minerals and gemstones such as amethyst, beryl, garnet, emerald, and extensive pockets of rose quartz. Quartz can contain ‘impurities’ like titanium, which colours it the delicate and much-coveted pink colour of rose quartz.

Certain rocks of the NMMP are also host rocks to rare earth element (REE) deposits, these being important in the development of high-end technology lasers, magnets, electronics and fibre optics. The Northern Cape is also rich in banded jasper and tiger’s eye, deposited with the Sishen iron ore Transvaal Supergroup deposits some 2 000 to 2 500 million years ago.

EIA applications Undergoing an EIA process requires knowledge of the National Environmental Management Act, No. 107 of 1998 (NEMA), National Environmental Management: Biodiversity Act, No. 10 of 2004 (NEMBA), and National Water Act, No. 36 of 1998. It also requires understanding how to design a mine work programme, with the necessary mitigation in place to minimise negative impact on the surrounding biophysical environment and improve the socio-economic and cultural circumstances of local communities.

The process also requires a grasp of geology, hydrogeology, heritage and environmental law, plus botanical proficiency and sound geographic information system

High on the priority list for both the DMR and the DEA is the commitment from the mine company to rehabilitate the disturbed area and to reinstate the surface to original land use. This is normally agricultural livestock or crop production, if farmed, or natural vegetation. When granting a mine licence, the DMR and DEA will need a full rehabilitation plan as part of the EMP. Another requirement is a quantum – which is a cost calculation for a rehabilitation plan by an independent contractor, should the licensee be unable to carry out such works. The quantum’s value must be deposited in a DMR account or provided as a bank guarantee.

Calculating the quantum and facilitating the process also requires the knowledge and expertise of consultants, who will balance the needs of the environment with the law, while being mindful of the financial position of the mining company. The mining company undertakes the actual rehabilitation procedure. This is clearly the most cost-effective option, given that all machinery and labour are already on site and no establishment costs would be required. Where large or complex rehabilitation is required, and where the receiving environment is unusual (as in the Northern Cape, with low rainfall and a threatened and vulnerable

vegetation biome), it is advisable for the licensee to appoint a specialist rehabilitation company.

Umvoto Africa Umvoto Africa is an earth sciences company offering an array of services to the small- and medium-scale mining entrepreneur requiring mine permits, prospecting permits, mine rights, and performance assessment audits. In addition, it offers all associated mining services such as hydrogeological assessments and groundwater development, rehabilitation, water-use licence applications, South African Mineral Resource Committee reserve statements and mine work programmes. The company supports a turnkey approach, from greenfield concept through to the granting of the environmental authorisation and licence.

Note: Rowena Hay, managing director, Paul Lee, senior environmental scientist, and Dylan Blake, senior geologist are all of Earth Sciences consultancy Umvoto Africa.

2

1

Rehabilitated mining grounds

2

Umvoto Africa MD Rowena Hay

3

mvoto Africa senior environmental U scientist Paul Lee

4

Senior geologist Dylan Blake

5

Red jasper mined, cleaned, and ready for export

3

4

5 In sid e M in in g 0 6 | 2015 31

drilling & blasting

Tracking and control systems When associating the name Komtrax with something, the complex world of virtual technology comes to mind, as do two famous quotations – ‘prevention is better than cure’ and ‘you can’t manage what you don’t measure’. Now there is AHS!

P

developed by Modular Mining Systems, roper and timely mainteare remotely controlled from the central nance of equipment can save control room for unmanned hauling in the a considerable amount of time segregated area for AHS operation. Informaand money. Komtrax Plus is a tion on target hauling routes and speed is machine-tracking system developed by sent automatically from the central control Komatsu to transmit information conroom to AHTs, via the wireless network syscerning the location, cumulative hours of tem, which then run on the target courses operation, and the operating conditions of at the target speeds by assessing their own vehicles and equipment. This detailed inforpositions via GPS and dead-reckoning navmation is sent via satellite communications igation systems. Manned loaders, such as to a data server and on to an application hydraulic excavators and wheel loaders, can server, where it is analysed to determine also be equipped with GPS so the fleet mana specific piece of equipment’s ‘health’. It agement system can determine the position also provides other useful information relof their buckets. ative to the operating conditions of that The fleet management system automatipiece of equipment. cally guides AHTs to the designated loading Information is sent back to the jobsite, ussite and sends information concerning a ing the Internet, from a remote location on route to the unloading site, to ensure safe a near-real-time basis. By proactively using and precise unloading. By controlling AHTs the information gained from the Komtraxand monitoring, in real time, the position equipped machines, Komatsu is able to of manned machines, such as loaders, provide value-adding after-sales support, bulldozers, motor graders, and service vethroughout the machine’s lifetime. This hicles, the fleet management system endelivers reliability, availability, and lowered sures safety and effective collaboration in maintenance costs, which translate into the AHS-controlled area. If another vehicle higher productivity, and an improved botcomes close to AHTs in operation, the obtom line. AHS, which stands for ‘automated stacle detection sensors on the AHT detect haulage system’, is a remote-control system it and the concerned AHT will make an to run super-large driverless dump trucks emergency stop for safety. based on the 930E/830E. AHS makes important contributions FIGURE 1 How Komtrax works to mining operations by improving safety, economy, productivity, and environmental conservation, and is the world’s first system of its kind, featuring Komatsu original technologies, which are unrivalled by any other company. AHS dump trucks (AHTs), installed with high-precision GPS, obstacle detection sensors, various controllers, and wireless network systems

32 I n sid e M in in g 0 6 | 2 0 1 5

drilling & blasting

Delivering the bottom line

C

aterpillar’s customer -inspired MD5150 Track Drill delivers more power and more airflow for fast, efficient drilling of holes up to 152 mm (6 inches) in diameter, and blazing fast set-ups. Building on more than 50 years of track drill design, this machine incorporates a proven rock drill, patented carousel rod changer, functional cab, and many other features that boost productivity and reduce operating costs.

The carousel rod changer, which holds six rods and accommodates multiple lengths and diameters of drill steel, dramatically reduces set-up time. Its powerful dual-rod grippers and a unique gate design let the rod and gate move simultaneously, reducing cycle time. The rod changer is supported by a sturdy feed and heavy-duty 2.4 m boom that extends to 3.3 m for larger pattern coverage with fewer set-ups. Because the carousel rod changer weighs less and holds more rods than linear models, the boom extension can reach farther and drill deeper, while maintaining stability. Holes can be drilled within 610 mm of the highwall, which is 50% closer than with a linear rod changer.

Critical to any machine being in the field is its reliability, longevity, and low ownership costs. With less than half as many moving parts as competitive rock drills, the MD5150’s simple, reliable design offers dependable performance and exceptional durability. Owners can service the rock drill themselves to reduce downtime and control costs. A new automated lube system keeps the rock drill working

Today, more than ever, the focus in mining is productivity and minimising costs. Technologies that are designed to deliver these business objectives are literally worth their weight in gold. The Cat MD5150 is such a technology. productively, eliminating the need to stop the machine for manual greasing every two hours. Efficient drilling in hard rock applications requires exceptional power and airflow. At the heart of the MD5150 is the Cat C11 engine, which is rated at 287 kW (385 hp) at 1 800 rpm. Designed for high performance and excellent fuel efficiency, the engine meets US Tier 3 and EU Stage IIIA emissions standards. The high-horsepower engine works as a system with a biggest-in-class air compressor to optimise air flow. An oversized, highefficiency cooling system further improves performance and lifespan.

Operator safety and productivity is paramount. The MD5150’s cab is ROPS/ FOPS-certified and incorporates numerous shutdown methods, accessible from the cab or at ground level. Large windows, streamlined front structures, and a skylight enhance visibility, as do well-placed mirrors and high-resolution cameras.

The front window provides a secondary emergency exit. And, to boost operator comfort and productivity, the cab features automatic climate control, excellent ventilation, a fully adjustable seat, ergonomic controls and switches, and low sound levels (less than 80 decibels).

To further improve operator productivity, the machine is equipped with a smart drill-monitoring system that tracks changes in rock formation and automatically adjusts impact and feed pressure based on the hardness of the rock. The system’s anti-jam, anti-plunge, and anti-plug capabilities keep the track drill working efficiently and extend drill string life. As to

its serviceability, the onboard Caterpillar Electronic Technician (Cat ET) speeds up the troubleshooting process, improving repair accuracy and reducing downtime.

Cat Product Link™ allows for remote monitoring of machine location, service meter hours, fuel usage, and other critical factors, providing owners with the information they need to optimise utilisation and reduce owning and operating costs.

As with everything these days, reducing environmental impact is important. The MD5150’s high-capacity dust collection system works quickly and quietly, while consuming less power than traditional dust collectors. The C11 engine offers excellent fuel economy and reduced emissions. The machine’s automated lube systems are clean and efficient. Major components are designed to be rebuilt for second lives, and Cat dealers offer a full selection of remanufactured parts and components.

All in all, it is a solid machine.

In sid e M in in g 0 6 | 2015 33

Pipes, pumps & valves

Fissure water beneficiation A strategy for beneficiation of wastewater streams from fissure water, developed for a gold mine operation in the west of Johannesburg, was tested for viability in a pilot study. By Lelanie de Kock, AECOM

T

he water is pumped from underground to surface level and collected in a fissure water tank.

From this tank, the water is disinfected before entering a dual-medium filter. The filter media consist of granular activated carbon and silica sand. After filtration, the water is distributed to different sources on the mine. A small portion of the filtrated water is used for testing in a pilot plant. The pilot plant consists of three processes, namely: crystalactor (cold lime softening), cation exchange, and degassing (CO2 stripping).

The crystalactor is a fluidised bed reactor and used for cold lime precipitation, in order to remove calcium and soften the water. The feed flow rate to the crystalactor is 20 000 â&#x201E;&#x201C;/h. The water enters at the bottom through six nozzles in order to achieve good distribution inside the reactor. The water flows through the reactor and exits at the top, where it overflows to the next process.

Figure 1 The crystalactor, a fluidised bed reactor

34 Ins i de Mi n i n g 0 6 | 2 0 1 5

Figure 2 The fissure water pilot plant is located at a pumping shaft in the West Rand

the precipitation takes place, the seed material grows and the heavier particles move to the bottom. As the particles grow, the level of suspended particles rises. Due to this constant growth taking place inside the reactor, some of the larger The objective of the reactor is to maintain particles are removed daily and replaced a pH of 9 in order for cold lime precipiwith fresh seed material to increase the tation to take place. The pH is sustained available surface area. The particles disthrough the addition of lime to the botcharged from the reactor are sent to a drytom of the reactor. The lime addition is ing bay to remove most of the moisture controlled with a proportional integral depresent. The particles are then referred to rivative (PID) controller, which increases as pebbles. The lime used for the pH or decreases the pumping speed according control of the crystalactor is slaked in a to the pH measured on the crystalactor 1 000 â&#x201E;&#x201C; batching tank; if the tank is empty, overflow. Inside the crystalactor, seed maa pump will start feeding product water into it.

Once the tank starts filling up, The objective of the agitation is applied through a reactor is to maintain a mixer, agitating at a low speed to prevent turbulent behaviour pH of 9 in order for cold and introduce air into the water. lime precipitation to As the level rises in the tank, lime powder is fed into the tank take place through a screw feeder above the tank. The screw feeder will be in operation for short durations as the waterial is fluidised. The seed material proter reaches certain levels inside the tank. vides a large surface area for the precipiOnce the tank is full, the lime is pumped to tation to take place. At a pH of 9, calcium the lime storage tank from where it is fed carbonate forms from the reaction of the to the crystalactor, and the next batch is water and the lime. The calcium carbonate prepared. After the cold lime precipitation then precipitates on the seed material. As

Pipes, pumps & valves

process, only 2 000 ℓ/h of the treated water continues on to the cation exchange section of the plant. The reason for this is that the crystalactor cannot be scaled down any further than 2 000 ℓ/h without compromising efficiency.

The water enters the resin column at the top and flows down through a strong-acid cationic resin bed to the bottom of the column, where it exits. Inside the column, cations such as calcium, magnesium, and sodium are exchanged through adsorption on to the resin for hydrogen ions, which are released into the water. The water exiting the column has a high conductivity and a low pH, due to the hydrogen ions released into the water.

Once all available adsorption sites of the resin are loaded with cations, breakthrough is achieved and the resin requires regeneration. The pH of the water exiting the cation exchange column is monitored continuously. As the resin approaches breakthrough, less hydrogen ions are released into the water and the pH begins to rise; once the pH reaches 5, the plant automatically begins regeneration.

Figure 3 A schematic view of the crystalactor

The first step of regeneration is the release of all cations on the resin sites. This is achieved by pumping 1.5 bed volumes of 4% nitric acid through the column at a flow rate of 900 ℓ/h (2 bed volumes per hour).

The nitric acid will exchange hydrogen for

cations such as calcium, magnesium, and sodium to form calcium nitrate, magnesium nitrate, and sodium nitrate. After the regeneration with nitric acid, the column is rinsed with 3.5 bed volumes of product water to wash any regenerant left in the In sid e M in in g 0 6 | 2015 35

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The treated fissure water will be used as drinking water column. Rinsing takes place at 2 500 ℓ/h (8.3 bed volumes per hour). After rinsing, the system returns to its initial conditions.

The water exiting the cation exchange column proceeds to a degassing tower at a flow rate of 2 000 ℓ/h. The water enters the tower at the top then cascades down through a packed bed and exits at the bottom of the tower. The tower has a blower at the bottom that blows air upward though the packing and out the exit at the top of the tower. The aim of the degassing tower is to remove any carbon dioxide present in the water. The carbon dioxide is released by the packing and will move with the air to the top of the tower where it is released into the atmosphere. An alternative to the degassing tower is a weak base anionic resin column. This column removes all anions present in the water. The treated

fissure water will be used as drinking water. In order to achieve the specified drinking water standard, water blending is extremely important. The blending takes place between the feedwater, the crystalactor overflow, the cation product water, and the anion product water. The blending is established through control over the different flow rates of the different streams.

Chemical composition of fissure water The water is not contaminated by any mine process or infiltrated with any poor-quality water at the mine. The fissure water input is mainly rainwater infiltration through the top layers of the underground workings of the mine. The water is kept separate from the mine water at high levels and pumped separately to the surface. The water contains a little bit of temporary hardness but is, otherwise, suitable for human consumption. Biological non-compliance still needs be tested and a disinfection process still needs to be developed. The aim of

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the pilot plant was to produce water that would comply with the SANS 241:2011 standard for drinking water. The fissure water was compared with SANS 241, and had very few non-compliant factors. The conductivity and hardness of the fissure water were the biggest concern. Heavy metals were within the specifications required by Rand Water, except for selenium, which would be removed through ion exchange. The fissure water required only softening and a small reduction in overall salt load. Although the plate count was above the limit, it was not consistent and caused no concern as the water still needed to undergo a disinfection process prior to usage (Bester, 2009).

Conclusion and recommendations The crystalactor was able to reduce the calcium hardness of the water to between 40 mg/ℓ and 35 mg/ℓ. The lowest flow rate removed more calcium hardness, but will require a bigger unit in the full-scale operation. In larger units, a higher flow rate can achieve the same efficiency. The performance of the crystalactor was better

at higher alkalinities. The feed pH, calcium content, and alkalinity should determine the lime dosing. The alignment of the reactor is important to prevent bypassing in the column. Therefore, care needs to be taken in the manufacturing of the column to prevent any bypassing within the column. The crystalactor produced calcium carbonate pebbles of high value, with very low metals content. The strong and weak acid cationic resins were successful in the softening of the fissure water. It is suggested to use SAC instead of WAC, due to the fact that a smaller portion of water is treated when using SAC. The anionic resin was more efficient than the degas tower in reducing the dissolved solids, as well as increasing the pH of the cationic water. Blending of the different water streams produced good-quality drinking water. The best results were achieved when only a small portion of cationic product water was mixed with the blend. It is also a good idea to add a relative portion of the anionic water as this water contains the least amount of salts.

Reference: Beneficiation of Wastewater streams from Gold Mine Process Water Systems with Recovery of Value-Adding Liquid Waste Products, Lelanie Bester, University of Pretoria, July 2012

Organisms in fissure water

S

ome years ago, a team of researchers from the University of the Free State, led by Prof Derek Litthauer and Dr Esta van Heerden, visited the Kloof gold mine near Fochville to look for organisms underground. They found a few of these minute creatures in fissure water.

This amazing discovery redefines life as we know it. As Dr van Heerden explained, these organisms may help to give us an insight into whether life exists on other planets. “The study of deep underground ecosystems in ancient groundwater is directly relevant to the search for extant life in the subsurface of Mars.

If life can exist in geological formations up to three kilometres below the Earth’s surface, it makes the discovery of life on planets such as Mars, or the moons of Jupiter, so much more plausible,” she

said. One organism, an as yet unnamed new species, was isolated aerobically at 60°C (for each kilometre one descends beneath the earth’s surface, the temperature increases by between 10°C to 15°C).

Three new organisms, also unknown to man until now, have been found in the fissure water pockets. A further 20 to 30 organisms are also presumably new, although tests are still being conducted to verify this.

Van Heerden forms part of a group of researchers whose work on the mine fissure water is being funded by NASA, the US’s National Science Foundation, and South Africa’s National Research Foundation. The funding is channelled through a programme called Life in Extreme Enviroments (LexEN). On 17 and 18 June 2015, a team of scientists from the USA will be joining Van Heerden for a visit down the Beatrix gold mine to

further their research. Inside Mining will be going along and will report back in its August 2015 edition.

BELOW Dr Esta van Heerden, with a NASA sticker on her helmet, and Prof Derek Litthauer working in Kloof gold mine at Fochville, in the North West, to extract living organisms from fissure water

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Intertek Minerals

Global Leaders in Minerals Inspection, Assaying and Testing Services across the Resources Cycle Intertek offers world class mineral inspection, assay and testing services to the Minerals, Mining and Exploration industries on a global basis. Intertek operates strategically located laboratories and sample receipt / preparation facilities across a number of countries within the African continent. These facilities service multiple commodities from Gold, Platinum Group Elements, Iron Ore, Manganese Ore, Copper, Nickel, Energy Minerals, Uranium and Rare Earth Elements.

Our African operations include laboratories and sample preparation facilities located in: • South Africa • Namibia • Mozambique • Eritrea • Ghana • Kenya • Zambia Supporting the African operations are Intertek’s team of global experts and state of the art analytical hubs. Intertek operates 1,000 laboratories and offices with over 38,000 employees in 103 countries world wide.

Our network of Mineral laboratory facilities operate to ISO17025 standards, offering a wide range of services including; • Sample Preparation • Fire Assay and Precious Metal Analysis, specialists in PGE analysis • Exploration Geochemistry • XRF analysis • Environmental Services • Dedicated Preparation Facilities • Mine-Site Laboratories • Automated and Robotic laboratories • Coal Testing and Inspection • Consulting Services • Minerals Inspections – quality and quantity • London Metal Exchange (LME) approved assay facility, providing exchange and umpire analysis services for non-ferrous metals and concentrates as well as ferro-alloys Talk to us about tailored exploration suites or customised onsite mine and process control laboratories to suit your needs at all stages of the mining cycle.

Contact us

www.intertek.com

Intertek Mineral Services Africa 43 Malcolm Moodie Crescent Jet Park, Gauteng South Africa, 1459 Tel +27 11 552 8149 min.zaf.jhb@intertek.com

mINERAL ANALyTICS

Elementary, my dear Watson Elemental analysis, the process whereby mineral samples are analysed for trace elements and composition, is fast becoming the critical success factor in mining today. By Tony Stone

W

ith much of the known high-grade ore already mined, physics and chemistry – coupled with optimised metallurgical process design, to maximise the yield from lower-grade ore deposits – are the technological innovations in mining that will rise to distinction.

Why? Maximising yield for minimal costs is the Kasparov queen in winning today’s profit game. This means that the right sampling tools are essential to finding deposits and judging their viability. Playing detective, like the great Sherlock Holmes, is absolutely essential.

This is because maximising exploration budgets, pre-screening laboratory samples, identifying drill targets quickly, reducing remobilisation costs, and getting accurate reports to the capital markets as fast as possible are all key factors in business optimisation and sustainability.

Quantitative analysis There are essentially two methods of quantitative analysis. The first, the traditional method, uses chemistry, while the second uses advanced, handheld machine technology, both of which are essential tools.

The analytical accuracy of the latest handheld and field-portable analysers in mining is now so good that the key limiting factor to receiving lab-quality results is adequate sample preparation – especially for the X-ray fluorescence analysis of elements lighter than calcium.

Out in the field The use of a portable, handheld XRF analyser avoids the need to identify, collect, store, and transport rock samples out of a mine for time-consuming chemical testing in a

laboratory. The handheld analyser produces results in a matter of moments and is one option for speeding up the exploration and on-site analysis process.

The most common uses, for example, of the DELTA Mining and Geochemistry Handheld XRF Analyzer, are to map deposits of base and precious metals, as well as rare earth elements and iron ore, and to: • rapidly delineate ore/waste boundaries • determine GPS coordinates and, at the same time, perform geochemical analysis • direct analysis of drill core and cuttings to dynamically drive exploration XRF programmes • enable real-time assay directly at the mine face, from bagged samples during survey or drilling operations, or from prepared samples • analyse raw materials to determine penalty elements in coal, iron ore, bauxite, and limestone.

In the case of precious metals like gold and silver, portable XRF technology can be particularly useful, as XRF analysers are particularly sensitive to the geochemical pathfinder elements like arsenic, copper, and zinc, the presence of which often indicates nearby precious metal deposits.

An earlier limitation in the detection capability of XRF technology has been eliminated by the development of a silicon drift detector for handheld analysers, which allows high pulse throughput without any associated loss of accuracy.

Back at the lab South African mineral exploration and mining laboratories use a variety of instruments and methods, which, dependent on the ore being mined, will determine their application. These include:

• optical microscopes, for reflected and transmitted light microscopy • scanning electron microscopes with EDS (X-ray) spectrometers, for imaging, identification, photography, and microanalysis • electron microprobes, for microanalysis (WDS spectrometers) • atomic absorption spectroscopy, for elemental analysis • X-ray powder diffraction • mineral separation, based on density (heavy liquid separation) and magnetic separation methods • rock and mineral SG determination • water remediation.

Safety in mines Gas chromatography plays a vital role in safety and production at each mine. Chromatographic data is used to monitor working areas for safety and proper ventilation, and to control the quality of extracted methane for sales purposes. The instrument itself has a high degree of automation, with an efficient structural design. It is especially suited for performing a variety of analytical processes easily and simply. This instrument is accurate, with short analysis times – perfect for analysing gas concentrations and preventing fires in the mine.

Practical reality Through the effective application of physics and chemistry, increased mine production and safety can be achieved. The role of an in-house laboratory, or even an outsourced laboratory service, such as Intertek, is vital and can be geared to maximise yield from mineral processing operations – a critical necessity in modern mining operations.

In sid e M in in g 0 6 | 2015 39

MINERAL ANALYTICS South Africa has between 119 and 200 years of coal reserves. Understanding the characteristics of coal and the relevant markets is vital to any mining start-up.

of fixed carbon plus any carbon present as volatile constituents (e.g. carbon monoxide, methane, and hydrocarbons). Total carbon is always greater than fixed carbon and calorific value increases with increasing total carbon.

• Ash: Ash is the total of non-combustible minerals contained within the coal. Presence of ash reduces its calorific value and presents handling problems. Ash originates from several sources, including the minerals contained in the original plant matter, mineral matter laid down with the plant matter, or minerals infiltrated into the peat.

• Hydrogen: Hydrogen in coal is associated with volatile matter. In metallurgical coals, the greater the H2 content, the greater the yield of NH3 in the coke oven gas, which is then used in fertiliser production. Hydrogen content generally increases the calorific value of coal, but is not related to coal rank, with hydrogen content ranging from 4.5% to 6.5%, from peats to bituminous coal.

• Moisture: A high moisture content in coal is associated with a lower calorific value.

• Sulfur: Sulfur can occur in coal in three

forms: sulfide minerals (such as pyrite), organic sulfur, and sulfate minerals. While sulfides increase the calorific value of the coal, the presence of sulfur is undesirable in the use of coal as a fuel. The oxidation products of sulfur can result in the corrosion of equipment and their release leads to local air pollution and acidification effects. Sulfur is also undesirable in metallurgical applications, causing cracking when the steel is forged or rolled at elevated temperatures. Sulfur content is not related to coal rank.

• Oxygen: The oxygen content of coal reduces its calorific value. The lower the oxygen content, the greater the rank.

• Nitrogen: Nitrogen appears in coals at between 1% and 3%. The presence of inert nitrogen reduces the calorific value of the coal, but does not relate to coal rank.

• Phosphorus: Phosphorus is a coal constituent that is problematic for metallurgical applications of coal, as it reduces the ductility of steel, causing cracking at low temperatures.

The most common chemical analyses undertaken and properties of coal include: proximate analysis, heat value, sulfur compounds, ultimate or elemental analysis, ash constituent analysis, and trace element/minor constituent analysis. The physical properties of the coal are also important parameters to consider, as they determine the behaviour of coal products during combustion and conversion.

As a mine owner, knowing your product will make you more effective in marketing your product.

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Intertek Minerals

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Pumptron 35

Characteristics of coal

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n South Africa, depending on one’s source of information, about 70% of the coal consumed annually is used for electricity generation. Coalto-liquid-fuel (CTL) plants account for approximately 20%, while small merchants, who supply mainly residential users and small businesses, account for about 2%.

Metallurgical industries use about 3%, leaving the remaining 5% consumed by the cement, chemical, and other industries. The chemical make-up of coal varies across all coal classifications (anthracite, bituminous, and lignite) but is largely dependent on the location of the coal and the location’s geological conditions. The chemical, physical, or petrographic characteristics of coal are an integral consideration in the trade and end use of coal, whether it is raw or beneficiated coal. The most important considerations are: • Fixed carbon: The fixed carbon content of coal provides the energy and metallurgical reductant ability for which coal is valued, with the higher the fixed carbon level, the higher the calorific value. Carbon levels increase with increasing coal rank.

• Total carbon: Total carbon is the amount

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tel: +27 13 690 2818 fax: +27 13 690 2867 email: info@nokoanalytical.co.za web: www.nokoanalytical.co.za Noko Analytical Services has been providing a high quality analytical, sampling and transportation of samples for over 8 years. Been a BEE African Company with hard work and total team dedication has continued to grow, from humble beginning our success is built on service delivery and long-term objectives.

our team provides solutions required in maximising the inherent value of your coal products, NOKO facility is accredited and it uses the same standard quality control procedures that exist throughout the world. We have capacity, expertise, equipments and skill to deliver the quality with turnaround time for proposed required market scope. Services are operational twenty four hours, seven days a week (24/7) .We are committed to ensuring quality and timely testing results & we our target market is mainly the coal mining industry from micro to macro.

our services

REAL TIME ANALYSIS • Design, commission, install, operate, calibrate and support of on-line analysis systems • Real time control of quality using sorting and blending systems

COAL PREPARATION PLANT SERVICES • Optimization and troubleshooting consulting.

• Process simulations.

• Third party services (monitoring,sampling and testing) INVENTORY SERVICES • Stockpile management services.

• Density determination.

• Tonnage calculation.

• Customized quality assurance programs,audits and training of inhouse methods and best practice habits.

• Auditing of processes and laboratory facilities to determine suitability.

• New laboratory set up costing,operating and full management of on site and near site.

• General daily trained labour as well as risk labour.

SAMPLING SERVICES • Design, construction and operation of mechanical sampling • Manual and auger sampling.

• Channel sampling.

• Sampling system audits, bias testing of processes and equipment, operation and preventative maintenance.

• Sample scheme planning with regards to “stockpile, bunker” sampling.

• Normal and specialized sample/product transportation.

All testing complies with ISO 17025