NEW COMAR PLANT DOUBLES PRODUCTION FOR MORE ASPHALT

Western Cape asphalt producer, More Asphalt has almost doubled production capacity at its Tygerberg Valley site outside Cape Town with a custom-built continuous mix asphalt plant from Comar.

Starting production in October 2018, the facility impressed its owners by exceeding its operating expectations and producing 100,000 tonnes in its first seven months. According to Owen Peringuey, executive director at More Asphalt, the manufacturing of the plant went very smoothly, in line with the set out plan and within the required timelines.

“It was a pleasure working with a company as professional as Comar,” says Peringuey. “They were able to design, manufacture and commission what we needed, and more.”

Comar’s team of experienced design engineers, using modern software tools, designed the 140 tonne-per-hour plant to suit the customer’s constrained site footprint. Space savings were achieved through the design and installation of a single combination drying and mixing drum in a counterflow configuration, incorporating a long-nose burner.

“Our years of experience in designing, building and operating these plants allows Comar to customise each plant to our individual customer’s particular specifications,” says Comar director Ken Basson. “As a 100% local company, we also understand the demands of local conditions, and build plants that maximise uptime and productivity.”

The new plant includes six cold feed bins for sand and aggregate and two recycled asphalt pavement (RAP) bins for fine and coarse fragment sizes. A baghouse for catching dust particulate emissions, as well as a state-of-the-art motor control centre in a 12 metre shipping container, are also key elements of the new plant.

“The facility uses a higher quality fuel than normal, providing better combustion and less sulphur burn-off,” says De Wet Dreyer, Comar operations manager. “Among the benefits of this fuel choice is longer bag life and reduced maintenance costs for the overall operation.”

As a result, the plant complies comfortably with new emission standards on dust particulate levels, which require that emissions do not exceed 50 mg/Nm3. A recent inspection of the plant confirmed it was dealing well with the high production volumes, showing little wear on the lifters and also minimal wear in the bags, which were operating highly efficiently.

The design provides for additional loadout flexibility should the customer require it. This allows a fourth product to be discharged directly onto trucks, while the three silos are filled. The scope of work for the More Asphalt contract included disassembling and removing the company’s old plant before installation of the new plant could begin.

PLANT EFFICIENCY AT RISK WITHOUT CAREFUL CHUTE DESIGN

The efficiency of crushers, screens, mills and other large equipment in a minerals processing plant can be severely undermined if the chutes at transfer points are not doing a proper job.

Mark Baller, managing director of Weba Chute Systems, highlights that chutes play a vital role in plant reliability and performance. “A well-designed chute ensures that a crusher receives the right material at the correct angle, for example,” says Baller. “By the same token, it will load a screen optimally, and will facilitate the correct feed rates into a mill, for best performance and economical power consumption.”

He argues that most plant operations are today recognising that chutes are not just basic plate-work. Rather, they need to embody a high level of technical design that creates a fit-for-purpose solution for the particular commodity and application.

“After 30 years of continuous improvement in our chute designs, we have worked hard to change the traditional mindset, which assigned chutes a sort of ‘step-child’ status in the process circuit,” he says. “More and more plant managers recognise that no two chute applications are the same, and that careful design must go into developing a solution to their specific operating conditions.”

Weba Chute Systems combines a scientific approach – including finite element analysis and the latest design technology – with its extensive experience in the field. The result is a customised solution that controls the flow of material, taking into account its physical properties and the surrounding conditions.

“We have seen many plant shutdowns caused by incorrect chute design,” Baller says. “Damage can include holes in screen decks or damaged conveyor belts. In addition to the repair costs, plants must pay even more dearly for plant downtime.”

On the other side of the coin, the savings achieved through good chute design – leading to more efficient plant operation and fewer stoppages – means that most of Weba Chute Systems’ installations can pay for themselves in less than 12 months.

The company has supplied over 4,300 chutes into the global market over the decades, of which about 3,500 are still operational.

TRAFO’S QUICK TRANSFORMER TURNAROUND AIDS KZN MINE

When a mining company in KwaZulu-Natal experienced a transformer failure recently, it was hoping for a quick solution. The mine got one from dry-type transformer specialist Trafo Power Solutions, who took just five weeks to design, build and deliver a non-standard cast-resin replacement.

“Once the situation with the old transformer was assessed, it was decided it would be more economical to replace the unit than to embark on major repairs,” says David Claassen, managing director of Trafo Power Solutions.

“We were able to accommodate the customer’s specifications in our replacement design, and have the unit manufactured by our European partners in just four weeks. After that, it took just a week to fly in the transformer and deliver it to the customer.”

Claassen notes it is not uncommon for transformer replacements of this scale to take anything from 12 to 14 weeks, so the rapid turnaround time by Trafo Power Solutions was highly valued by the customer. The mine required a 1,600 kVA dry-type DYN11 transformer that stepped 33 kV down to 550 V, with a non-standard tap setting arrangement of seven tap settings instead of the normal five.

“We are always willing to step in when a user has an urgent requirement, and to propose innovative solutions that meet customers’ priority needs,” says Claassen.

Dry-type transformers – also called cast-resin transformers – are growing in popularity as users recognise their safety benefits, as well as their economy and flexibility of placement. To meet this demand, Trafo Power Solutions works in close collaboration with established and well-resourced manufacturing partners in Europe to source tailored designs that meet customers’ exacting specifications. With its South Africa-based expertise and long experience all over Africa, Trafo Power Solutions provides users with peace of mind by ensuring ongoing after-sales service.

FLSMIDTH DOUBLES SIZE OF SUPERCENTER IN DELMAS

The formal opening of FLSmidth’s expanded facilities at its Delmas Supercenter in Mpumalanga is good news for customers, while boosting the engineering capability of the South African economy.

According to Stephan Kruger, FLSmidth Director for Manufacturing and Warehousing in the region, the added capacity of the facility will further contribute to the group’s productivity and customer service while improving stock availability and lead times.

The facility is now double the size it was a year ago, with a total of 10,500m2 under roof and under crane. The workshop is one of fewer than 10% of facilities countrywide that boasts a 120 tonne lifting capacity with 11,5 metres under crane hook.

“The expansion is aligned with our corporate mission to provide sustainable productivity enhancements for our customers,” says Kruger. “It raises our engineering capability to support local customers, while also improving our efficiencies to compete globally in certain lines of products.”

The Delmas facility engineers components for FLSmidth equipment, as well as whole assemblies and complete equipment. The addition of new manufacturing equipment in the workshop – including CNC-controlled six axis machines – will increase the range of items that can be machined on site. The work process has also been optimised to promote quality, reliability, efficiency and cost effectiveness.

The facility’s services include refurbishment, retrofitting and upgrading of existing equipment. It also holds substantial strategic stocks of spare parts such as exciter gearboxes, rotors and stators, as well as wear parts such as screen panels.

“The FLSmidth Delmas Supercenter is a world class OEM facility that consolidates and grows specialist expertise within the South African market, creating exciting opportunities for the future,” says Kruger. “This expansion is a vote of confidence in the specialised knowledge imbedded in this facility, which makes an important contribution to sustaining technical skill levels in South Africa.”

He emphasises the company’s commitment to safety, reflected in the Supercenter’s enviable record of just one lost-time injury since operations began over five years ago. Strict quality control is governed through the ISO 9001 standard and careful environmental management by ISO 14001 with safety to OHSAS 18001.

“FLSmidth’s commitment to continuous improvement is also embodied in this facility,” he says. “We are now in an even better position to play a role in value engineering for the group, particularly in our vibrating equipment and screens.”

In line with the company’s corporate social responsibility, the construction activities last year reached out to local small businesses, he adds. Some 5% of the value of the total budgeted spend was allocated to these firms, ensuring that they benefitted directly from the expansion.

MOTOR REHABILITATION IN ZAMBIA KEEPS MINE PUMPING

Marthinusen & Coutts’ Cleveland Engineering Services Division, a division of ACTOM (Pty) Ltd, recently teamed up with the Marthinusen & Coutts Kitwe facility in Zambia to rehabilitate medium voltage pump motors in one of the wettest mines in Africa.

A pump OEM had approached Marthinusen & Coutts, the largest after-market service provider of electrical and mechanical rotating machines in Africa, to assess several underground pump motors. There was an urgency to the situation due to the risk of flooding should there be any undue interruptions in pumping operations.

Investigations revealed that the motors driving the pumps were in a poor condition, with this severely affecting the availability and the performance of the pump chambers. This required the initiation of a detailed refurbishment programme, involving the procurement of spare parts, the setting up of an on-site bearing store, and taking the lead in returning the motors to full service.

Where possible, the motors were repaired in situ – thus avoiding any possible crisis of underground flooding – while others were removed for full refurbishment. The highest level of engineering practices where followed during repairs, re-installation and commissioning. Ongoing support is also being provided, including the training of mine maintenance staff, the development of installation and commissioning specifications, conducting of regular site inspections, management of spares, and continual engagement with mine engineering management.

Marthinusen & Coutts operates six state-of-the-art repair and manufacturing facilities – in Johannesburg, Benoni, Sasolburg, Rustenburg, Harare and Kitwe. Supported by a network of technically equipped partners throughout Africa, it provides services not only in Africa but globally.

CONCOR BUILDINGS GIVES NEW SHINE TO SKUKUZA WITH SANPARKS SAFARI LODGE

The wildlife-loving public can look forward to another upmarket venue in the Kruger National Park after Concor Buildings recently completed a new three-star safari lodge at Skukuza camp.

Developed by South African National Parks (SANParks), the exciting development adds a new dimension to the Kruger Park offering, slotting in between the traditional camp accommodation and the top-end private lodges. Planned and constructed as a ‘green building’, Skukuza Safari Lodge boasts 128 units, including 87 standard rooms, 20 family rooms and 13 universal rooms with easy access for wheelchairs.

Facilities at the lodge include a restaurant, bar, meeting rooms, gym, pool and laundry, as well as overnight accommodation for 16 staff. With a focus on environmental care, the lodge has been designed to combine the Leadership in Energy and Environmental Design (LEED) Green Building Principles as well as the requirements of the Green Building Council South Africa (GBCSA). This meant that targets for lower energy usage as well as water savings were also built into the planning.

Work began when the Concor Buildings team moved onto site in February 2017. Practical completion was reached in October 2018, and the team plans to leave site at the end of March 2019. According to Concor Buildings’ site agent, Christopher Martin, the environmental focus was taken on board by the team and applied with commitment in various ways.

“There were over 50 existing trees on the site, including two iconic baobabs in pristine condition,” says Martin. “We worked hard to accommodate important natural resources like these, even redesigning the parking areas and moving one of the buildings to be more sensitive to the existing landscape.”

In line with green building requirements, the two-level structure does not protrude above tree level, minimising its visual impact. Advances in lightning protection have been harnessed, with integrated protectors being used in place of the tradition lightning poles that are very tall and generally unsightly.

Even the provision of lighting is designed in a way that reduces light pollution. Water efficiency is prioritised through rainwater harvesting, grey water treatment and a dual-flush system in toilets which use recycled water. Low-e coatings on windows allow guests to enjoy unimpeded views of the natural beauty from indoors, while keeping out the heat. This, in turn, improves the energy efficiency of the building, reducing the power required for air conditioning. Innovative design also ensures that windows do not face direct sunlight.

Architectural timber is a prominent feature of the lodge, with laminate saligna beams used for long-span trusses. Thatched roofing and grass ceilings add to the natural ambience, along with design elements from local cultures. While making every effort to be non-intrusive, the lodge is a substantial construction with 5,200 m2 of decking. Over 3,600 m3 of concrete has been poured over 150 tonnes of reinforced bar, and 1,8 million bricks have been laid. The coverage of roof thatching measures over 3,600 m2, while 5,000 m2 of sheeting has been used.

In recognition of the authentically wild surroundings of the lodge, an important use of the concrete was in the bases of the game fence. The fence has been built all around the lodge, with substantial bases measuring in size from 1,5 m by 1,5 m to 1 m by 1 m.

The site itself presented a few challenges, with much of the infrastructure dating back many decades and not all precisely recorded in terms of location. Further investigation through radar technology and even geographic positioning systems (GPS) was sometimes necessary to identify underground services. Most services such as fresh water, grey water and sewage had to be rerouted in line with the needs of the new structures.

“Waste was carefully managed on site, with the assistance of a contracted specialist to help us sort and recycle waste,” Martin says. “As the project progressed, we were also able to contribute towards restoring and rehabilitating some of the old borrow pits in the area.”

An ongoing challenge was the distance between the site and the towns from which products and services were sourced. Being two hours from Nelspruit, for instance, added to the logistical burden and lengthened lead-times, especially considering the road speed restrictions within the Kruger Park.

“Transporting readymix concrete from the batching plant in Hazyview was a particular challenge,” says Martin. “The distance factor was compounded by the high ambient day-time temperatures, which could reach 45 degrees Celsius during our building phase. Adding a retarding admixture allowed us to extend the concrete’s workability window to two hours.”

The movement of workers between their homes and work was also an onerous process that required careful management. While Concor Buildings exceeded the client’s brief by employing 100% of general labour from local communities, those communities could still be up to 150 km from site. Training was an important part of the project, upskilling local worker in terms of safety practice, concrete work, bricklaying, plastering and plumbing.

To combat rhino poaching, security measures in the Kruger Park have had to be stepped up. These stringent measures affect the movement of everyone in the park, including construction workers. The necessary checks and procedures added to transportation cycle times but simply had to be managed by the team in a responsible way.

Despite the remote location, the project was able to promote local suppliers by spending more than the required 30% of procurement value within 150 km of the site, using vendors with B-BBEE Level 3 or higher.

“Given the importance of community participation, we engaged a community liaison officer from the local area to work with us on our various initiatives,” Martin says. “In addition to facilitating employment, he also assisted with community development interventions such as the donation of salvaged building materials, school sports events, an anti-poaching campaign and soccer kit donations for a local tournament.”

EFFICIENT OPERATION FROM LOCALLY MANUFACTURED CAVEX® CVXT HYDROCYCLONE

Locally manufactured by Weir Minerals Africa, the Cavex® CVXT tile lined hydrocyclones is available in a large range of sizes to process any feed tonnage requirement. All components are designed for ease of maintenance and efficient operation.

The Cavex® CVXT tile lined hydrocyclone features unique laminar spiral inlet geometry designed to deliver sharper separation, maximum capacity and, importantly, a longer wear life than conventional involute and tangential feed inlet designs.

This innovative design provides a natural flow path into the cyclone body, allowing the feed stream to blend smoothly with the rotating slurry inside the chamber. The result is greatly reduced turbulence through the whole cyclone, dramatically improving the separation efficiency of the hydrocyclone.

The Cavex® CVXT hydrocyclone can be fitted with an extended barrel which maximises efficiency by increasing the residence time in the hydrocyclone. This is especially for ore with a high content of near density materials. The hydrocyclone is also available with different overflow configuration options to suit operational needs.

To maintain separate efficiency at different operating yields and spigot sizes, a wide range of vortex finder sizes ranging from 0.4 to 0.5 is available. These are designed to maintain a strong air-core at the different sizes. The spigot sizes range from normal to extra high capacity to accommodate low yield ores. These can also be manufactured in different material to prolong the hydrocyclone life and efficiency.

CONTACT-FREE AND WEAR-FREE OPTICAL COMMUNICATION SIMPLE WITH LEUZE

Optical data transceivers are the appropriate choice for any application where data needs to be transmitted without cables and without interference. The Leuze DDLS 500 data transceiver makes contact-free and wear-free optical communication a simple task.

Especially suitable for applications where mechanical systems are pushed to their technical limitations, this robust optical data transceiver has a patented singe hand adjustment process making it quick and easy to achieve precise alignment of the data light beam. Data transmission of longer distances is just as simple as the unit has an integrated laser alignment aid. Four laser spots on the floor assist in the accurate alignment of the device.

Equipped with Leuze’s availabilitycontrol, the transceiver offers constant monitoring of the receiving level which means that in the event of an impending failure the user will be alerted.

The Leuze DDLS 500 supports all common Ethernet protocols including Profinet, EtherNet IP, EtherCat, Ethernet TCP/IP and Ethernet UDP. The device offers real time optical data transmission at 100 Mbit/s over a distance of up to 120 metres.

Access to technical support and information is via local Leuze distributor, Countapulse Controls. The company offers a comprehensive range of sensing, measurement, counting, switching, monitoring and positioning instrumentation, and supports customer through its technical advisory service hotline which is available 24/7.

VENT BLOCK SEALER IS A BOON FOR COAL MINES, AND OTHER USES

Developed to assist coal mines to seal their ventilation walls and air-crossings, the CHRYSO® Vent Block Sealer can, in fact, seal any porous substrate – quickly and cost-effectively.

With its continuous product development of value-added solutions, CHRYSO responded to the coal mining industry’s need to address ventilation wall leakage, according to the company’s new business manager, Frans Bakselerowicz. The styrene acrylic copolymer sealer efficiently addresses the challenge of hollow blocks and joints in the walls.

“The conventional use of a bitumen emulsion paint-on application product had proved to be very labour-intensive and costly,” says Bakselerowicz. “By contrast, the CHRYSO® Vent Block Sealer is an easy spray-on product, using a knapsack pump which does not need any compressed air to spray. This allows its application even in back‑areas of a mine, where there are no electrical and compressed air services available.”

The ventilation walls in a mine are usually made of concrete hollow blocks, clay bricks and corrugated iron sheets. However, he emphasises that any porous substrate can be sealed, as it can bridge gaps of up to 1 mm in magnitude.

Any larger crack or hole can be repaired with a.b.e. paintable flashing tape and then sprayed over. In high leakage areas, a second coat can be applied if required.

“Among the advantages of CHRYSO® Vent Block Sealer is that it is easy to use, and does not require specialist skills,” he says. “As a non-flammable product – in other words it does not sustain flames – it is ideal for use in coal mines and other potentially hazardous areas.”

It is non-toxic, requiring only the minimum PPE of goggles, gloves and overalls. Adhesion properties are excellent, and it dries quickly in just 30 to 45 minutes above ground and in only two hours underground.

Being water soluble makes for easy cleaning of equipment, and its cream colour allows users to immediately identify which areas of the grey ventilation walls have been treated.

ZEST WEG GROUP HELPS FARMERS FIND GOOD ‘GROUND’ – ELECTRICALLY

According to Zest WEG Group, there are misconceptions around what constitutes ‘earth’ (or ‘ground’) and ‘neutral’ connections and not understanding the differences can create serious problems when connections are made from on-site transformers or other sources. This more often than not leads to earth leakage systems underperforming and compromising the safety of the equipment and operators.

Johan Breytenbach, transformer sales specialist at Zest WEG Group, says that the neutral connection in an electrical installation is designed to carry current all the time, while the earth connection is only supposed to carry current for a short period to trip your protection switch.

“Where this is not understood and the installation is not done correctly, the trip system will not work properly. In addition to this, stray currents are created that could cause other problems,” he says.

Experience has shown that many farmers use the neutral connection as the earth when they do an electrical installation, and this is not correct. Current carried on a grounding conductor can result in significant or even dangerous voltages on equipment enclosures. For this reason, the installation of grounding conductors and neutral conductors is carefully defined in electrical regulations.

In alternating current (AC) electrical wiring, the earth is a conductor that provides a low impedance path to earth so that hazardous voltages do not find their way to the equipment. Under normal conditions, the earth connection does not carry any current. Neutral, on the other hand, is a circuit conductor that normally carries current back to the source.

Neutral is usually connected to earth at the main electrical panel or meter, and also at the final step-down transformer of the supply. Neutral is also the connection point in a three-phase power supply to connect cable termination in order to gain single phase power. In a three-phase circuit, neutral is usually shared between all three phases, with the system neutral being connected to the star point on the feeding transformer.

Earthing is therefore a vital part of electrical installations to ensure that circuit breakers will trip under fault conditions. Safe and legal installation needs to start with the selection of the right transformer, with a star configuration to allow the connection to the neutral point. Installation by a qualified and experienced technician is then ideal, to ensure optimal performance.

The correct earthing or grounding of electrical currents has a number of important benefits apart from the main concern around safety. It protects equipment and appliances from surges in electricity – commonly from lightning strikes or power surges – which bring dangerously high voltages of electricity into the system. Good earthing will ensure that excess electricity will go into the earth, rather than damaging equipment.

Zest WEG Group’s product line-up includes low and high voltage electric motors, vibrator motors, variable speed drives, softstarters, power and distribution transformers, MCCs, containerised substations, mini substations, diesel generator sets, switchgear and co-generation and energy solutions as well as electrical and instrumentation engineering and project management services.