ECOTAILS™ PROMISES ENVIRONMENTAL BONANZA FOR MINES

Combining filtered mine tailings with waste rock to form a GeoWaste is a breakthrough solution from FLSmidth that lowers water usage, rehabilitation costs and tailings footprints.

According to FLSmidth Regional Product Line Manager (Dewatering) Leonard Neluvhola, the Ecotails™ solution is nearing the end of a lengthy testing process by one of the world’s leading gold producers.

“The success of its application to date confirms that Ecotails will be a game-changer for the mining sector,” says Neluvhola. “Not only can mines improve their environmental performance by applying this system, they will also see bottom line benefits too.”

He says the Ecotails solution involves dewatering and filtering tailings to a point where moisture content is just 10% to 25%.

“Up to 90% of the water in tailings can therefore be reused in the plant,” he says. “This is a vast improvement on pumping highly diluted slurry to a conventional tailings dam, where the water is lost to evaporation.”

The drier tailings are then mixed with the mine’s waste rock, after it has been sized and screened to be transportable by conveyor. The resulting GeoWaste can be placed by a stacking system, as it is much more stable than wet tailings and can be stacked higher on a smaller footprint. This helps to address the serious concern mines have about the large footprints consumed by their tailings dams and waste rock dumps.

In addition to its greater stability, GeoWaste is more conducive to vegetation growth. It is an ideal medium for concurrent environmental rehabilitation. The concurrent approach is becoming more popular, as it can mitigate the costs and risks of mine closure. Wet tailings can also present a greater danger of land contamination through leaching.

“With our Ecotails experience and complete system offering, FLSmidth can provide a complete materials handling solution,” Neluvhola says. This includes crushers, sizers and screens, KREBS® pumps, thickeners and filters, conveyor and stacking systems, conducting tests and studies, system engineering and automation systems.

Neluvhola highlights that FLSmidth in South Africa collaborates with customers on in-depth testwork to ensure the application of Ecotails on their mines is fit for purpose.

“We can conduct testing at laboratory scale, and then advance to pilot stage when a mini-plant can be operated on site,” he says. “This allows us to test the technology using the customer’s own mined material in the thickening, filtering, conveying and blending phases to inform our technical designs.”

CONCOR BUILDING HANDS OVER CITY-STYLE MALUTI CRESCENT

Within the 13‑month timeframe and in time for its official opening on 21 March 2019, Concor Buildings has completed the Maluti Crescent regional retail hub, owned by Vukile Property Fund, at Phuthaditjhaba in Free State province.

The modern new development – designed to highlight the spectacular mountain scenery as well as the local culture – is expected to draw shoppers from as far afield as Kestell, Clarens and even Harrismith. According to Concor Buildings contract manager Martin Muller, the expansion added 12,600 m2 of gross leasable area (GLA) plus another 34,000 m2 of parking to the existing strip mall.

“This new mall is likely to be life-changing for consumers in the area, with a variety of brand-name stores moving in for the first time,” says Muller. “Adding to the shopping experience will be stunning architecture which celebrates local culture, highlights the sandstone colours of the surrounding area, and gives panoramic views of the Maluti mountains.”

Muller emphasises the positive local impact that the construction has achieved, with about 3,500 workers inducted into site activities over the life of the project. The numbers working on site peaked at over 1,000 before tailing off towards completion. The Concor Building team was even able to accommodate over 40 internship students from the University of the Free State at various stages of the contract.

“Despite the logistical challenges of the site’s relatively remote location, we managed this well through detailed planning and closely monitored project implementation,” he says. “Through our upskilling programmes and on-site training, a range of skills were transferred to local residents working on the project, including bricklaying, plastering, painting and tiling.”

He notes that a key consideration was to keep the existing shopping centre open and easily accessible to consumers at all times during the construction of the new mall. So enthusiastic were the locals that – far from being discouraged from the area – many came to watch the progress in anticipation of the new facilities to come.

The construction work also had to contend with an ongoing interruption to the mains water supply due to infrastructure upgrades in the town. This necessitated the use of tankers to provide the site with its regular water requirements.

Concor Buildings is part of Concor Construction which was acquired by a consortium led by Southern Palace Group.

CONCOR AT THE HEART OF CAPE PROJECT TO IMPROVE LIVES

Leading construction contractor, Concor is taking a leading role in one of the region’s most important and innovative public-private urban developments.

The Conradie Better Living Model project is aimed at improving the lives of Western Cape residents, and Mark Schonrock, property development manager at Concor Construction, says the new housing model is a real game changer.

“As a company we are excited to be involved in this project which is located on the 22 hectare site of the former Conradie Hospital near Pinelands,” Schonrock says. This residentially-led, mixed-use neighbourhood development will prioritise integration, sustainability and affordability.

Concor Construction has been tasked with executing the full development of the project. This includes all town planning, detailed designs, sales and marketing, funding, construction and handover to end-users. The multi-million rand initiative is being developed as a partnership between the Western Cape Government, the City of Cape Town and the private sector.

The core of the development is between 3,500 and 3,600 housing units; of these, of which about 1,760 will be grant-funded, affordable units. The initiative will provide affordable housing – reasonably close to Cape Town’s central business district – for families earning between R3,500 and R22,500 per month.

Sports facilities, a community hall and schools for 1,600 learners are on the plans, as well as up to 60,000 m² of commercial space and 15,000 m² of retail space. A three-star or four-star business hotel, with 160 rooms and 500 m² of conferencing facilities, is also planned.

The town planning scheme also incorporates substantial green belt areas with recreational facilities. The bulk of the zoning is MU2 (a category of mixed use in the Cape Town zoning scheme). The development framework and rezoning has been finalised and approved, and the precinct plans are currently underway.

An important benefit of the site – which is to the west of Thornton and north-east of Pinelands – is its proximity to public transport. It is within walking distance of both the Mutual and Thornton railway stations.

Although this is outside the control of Concor, there is also the potential for expanding other public transport modes, such as the MyCiti bus service. It is hoped that good access to public transport will make residents less reliant on private vehicles. The site will also have interconnected footpaths and cycling infrastructure as part of an integrated non-motorised transport plan for the area.

BOTTOM LINE BENEFITS FROM COMPOSITE MILL LINERS

FLSmidth has launched redesigned mill lining components engineered to suit the specific functions and differing operating environments of the mining industry. The new mill liners are designed to increase the throughput of semi-autogenous (SAG) mills and substantially increase the wear life of liners.

Delivering on a promise to provide increased productivity to the mining industry, the composite materials incorporated in FLSmidth new mill liners ensure users can take advantage of the wear characteristics of multiple materials, while extending the liners’ wear life.

With lighter weight mill liners, installation is faster and safer as each liner is easier to manipulate. There are also fewer parts, and hence fewer movements are required to perform a reline resulting in a significant decrease in scheduled downtime. The composite nature of the liner reduces its weight by almost 50%, allowing the plant to increase its ball charge level without increasing the total weight of the mill. This higher ball charge further contributes to the higher throughput.

The lighter weight of these liners has an important impact on size, design and installation time. Each liner can now be larger – subject to the size of the mill opening – and the mill can be lined with fewer of them, reducing the downtime required to conduct replacement. A lighter liner means fewer bolts to hold it in place, a factor further reduces installation time. The shorter downtime means less time for contractors inside the mills, leading to faster and safer liner changeout.

Another important benefit of the composite material used in many of FLSmidth’s redesigned liners is it is not necessary to torch the liners, as is sometimes required when removing old steel liners. This torching process in the mill is best avoided, as it can cause costly damage to the mill shell. Finally, there has also been the development of composite material shell liners that are bolted from the outside of the mill, speeding up installation and reducing risk.

“As mines increasingly recognise the positive financial impact derived from just a few more percentage points in throughput improvement, many are looking beyond conventional steel cast liners for mills. FLSmidth’s innovations, based on combinations of steel, rubber and ceramic components, allow the liners to be thinner, resulting in a larger volume inside the mill, making higher charge levels possible,” comments Jack Meegan, Product Line Manager for Comminution at FLSmidth.

“Responding to the continuous assessment of customer needs, FLSmidth has launched a mill liner solution based on extensive data on mill operations, shutdowns, wear profiles and other factors. These have been used to develop a high-end technical and financial solution. Following installation, an ongoing measurement of actual wear, tonnage processed and estimated wear life is conducted so further recommendations can be made to improve performance,” concludes Meegan.

The depth of technical and operational expertise within FLSmidth allows a high level of process support for customers assisting in mill operation and metallurgy. This is vital to the company’s strategic mission of helping customers achieve higher production and recovery rates. FLSmidth is also on hand with technical advisory services to assist with installation, so scheduled downtime is minimised and uptime optimised.

BENEFITS OF SLAGMENT GROW WITH RISING CARBON CONCERNS

As a leading producer of high quality cementitious material, AfriSam is ideally positioned to support customers seeking to reduce their carbon footprint while insisting on superior building material.

For over half a century, AfriSam has produced its trade-named ‘slagment’ from ground granulated blast furnace slag (GGBFS), according to AfriSam cementitious executive Hannes Meyer. “We have used this latent hydraulic binder in an extensive range of concrete applications, including major structures such as dams, bridges and roads,” says Meyer. “Indeed, it is only very specific and limited applications that today demand our cement without added slag.”

He highlights the self-cementing properties of slag, which can double the lifespan of buildings. Among its key benefits, however, is to prevent sulphate attack and alkali-silica reaction in concrete, especially in applications like wastewater treatment plants, or where there is seawater or sulphate-rich soil.

“However, there is now an added consideration in business today, as companies anticipate the impact of the new carbon tax,” he says. “Slagment assumes a significance here too, as it reduces the amount of clinker in concrete, and cutting the energy consumed and carbon emitted in its manufacture. The use of slagment therefore presents not just a technical solution but an opportunity to achieve higher environmental standards.”

AfriSam’s dedicated slagment plant in Vanderbijlpark has the capacity to produce over 800 000 tons of slagment a year, along with over 200 000 tons of blended cementitious products. The slag is a by-product of the steel and iron industry, and the plant mills this to a fine consistency before blending.

“As part of AfriSam’s sustainability journey, we have implemented various strategies in response to the energy-intensity of the cement manufacturing process,” says Meyer. “Slagment remains a vital part of this journey, and we continue to develop innovative ways of extending its benefits to customers.”
Another important capability of slagment is to reduce the thermal heat gradient generated when pouring concrete. This reduces the likelihood of micro-cracking, which may weaken the structure’s strength. Slagment can also alter the colour of concrete to near-white by replacing 50 to 70% of the concrete, giving the concrete a better appearance. In addition, it produces a smoother, more defect-free surface.

AFRICA FOLLOWS DRY-TYPE TREND AS TRAFO POWER SOLUTIONS GEARS UP FOR GROWTH

Africa continues to follow the global trend in taking up dry-type transformer technology, owing largely to its enhanced safety levels and lower maintenance requirements.

According to David Claassen, managing director of local dry-type transformer specialist Trafo Power Solutions, the growth of this market segment continues to extend the capacity of these units, which are now available in outputs up to 25 MVA.

“Africa has also been an enthusiastic market for the trend towards modular installations in applications like mining, water treatment and power generation. The safer, oil-free design of dry-type transformers allows them to be readily placed in modular substations, in close proximity to other equipment and personnel,” Claassen says.

In a partnership that will further boost the accessibility of dry-type transformer solutions across Africa, Claassen says that Trafo Power Solutions has now formalised its close collaboration with leading Italy-based manufacturer TMC Transformers.

“TMC is one of two leading designers and manufacturers of dry-type transformers,” he says. “After working with them for the past couple of years, we have signed an exclusive engineering partnership agreement to supply and service sub-Saharan Africa.”

Claassen emphasises the close alignment between the solution-focused approaches of the two companies. “We work together at all stages of each project from application engineering through to design, manufacture and customer support,” says Claassen.

TMC Transformers business development manager Roberto Deri highlights that the European company does not only manufacture standard products, but is driven by customers’ specific needs and project applications.

“This is the reason we are highly selective in our partnerships, as those companies with whom we work, such as Trafo Power Solutions, must have the engineering and design expertise to work closely with us on a technical level,” says Deri. “In this way, we fully leverage the capacity of our state-of-the-art design and manufacturing facility.”

The 25,000 m2 facility situated in Busto Arsizio near the Italian/Swiss border employs over 100 highly skilled technicians and professionals, and produces on average 16 complete transformer units a day.

Deri notes that TMC’s owners have over three decades of experience in this field, having built up their previous transformer business into a market leader worth €200-million before it was sold to a leading global OEM.

“Having purchased the TMC facility in 2017, the vision of our ownership and management team is to grow this business into a global force,” he says. “The company is already well on its way toward this goal, with rising global sales underpinned by a strong reputation for quality engineered products backed by solid technical support.”

Deri was recently in Johannesburg to exhibit – jointly with Trafo Power Solutions – at the well-attended Power & Electricity World Africa at Sandton’s Convention Centre.

DRY-TYPE TRANSFORMER EXCELS ON MOBILE PROCESS PLANT

Four dry-type transformers from Trafo Power Solutions have been proving their worth on a mobile process plant on a Sierra Leone mine since last year; so successful have they been that the customer has ordered six more for its recent Phase Two upgrade.

“The mine required a solution that would withstand the demanding conditions of a mobile process plant needing to be moved frequently over rugged mining terrain – as often as once a month,” says Trafo Power Solutions managing director David Claassen. “They could not risk using a conventional oil-cooled transformer as they needed to avoid any risk of fire or oil leaks. They also needed a product that would require little to no maintenance.”

The second contract was a repeat of the initial order, and comprises two 800 KVA units, one 1,600 KVA unit and one 2,000 KVA unit as well as a further two transformers, 1,600 kVA and 800 kVA which will replace two existing oil filled transformers. Demonstrating its flexibility in meeting specific customer requirements, Trafo Power Solutions designed the solution to cater for the mine’s unusual voltage levels of 13,2 KV/480 V at 60 Hz.

The transformers are installed in a six metre long E-house on the mobile process plant, which is moved around the site on skids as required by the mining plan.

“We were able to customise the design of the transformers for the customer’s specific application,” says Claassen. “This required a special reinforced frame to accommodate the constant vibration of the working plant, as well as the bumping motion when the skid-mounted plant is dragged to a new location. The design also included anti-vibration damping on the transformer feet, to further mitigate the impact of the vibration.”

The entry of Trafo Power Solutions dry-type transformers to the African market coincides with a growth in the use of modularised sub-stations. Due to the absence of oil as a coolant in dry-type transformers, they are suitable to be used in confined spaces without any of the conventional infrastructure usually necessary to protect the environment from possible oil spillage.

“Modular and mobile sub-stations are growing in popularity for applications all around Africa, as they can be fully prepared under workshop conditions, reducing the work required on site,” he says. “In terms of the installation of the transformer, for instance, we ensure that the temperature control relays are fully programmed and tested in South Africa, along with the fan system – making it ready for action on site.”

In the unlikely event of any further attention being necessary, Trafo Power Solutions can mobilise service support to any of the sites it supplies.