Monthly Archives: April 2021

Client Focus

ASSESS RISK, PLAN AHEAD BEFORE DECIDING ON PDS

As mines work to improve the safety of their trackless operations, the starting point remains a detailed risk assessment that will guide the correct selection of technology and proximity detection systems (PDS).

“There have been too many examples of mines incurring capital expenditure on PDS solutions that are not fit-for-purpose,” says Schalk Janse van Rensburg, chief technology officer (CTO) at Booyco Electronics. “More careful planning will ensure that the solution chosen can be well integrated into the mine’s operation.”

Janse van Rensburg highlights that PDS is a last resort in the risk management hierarchy, and that the mine safety regulations require a proper risk assessment to be done to indicate whether and how PDS will address the mine’s significant risks. 

Such an assessment needs to establish design guidelines for the mine, including site requirements for TMMs, segregation controls to prevent collisions, and operating procedures. Three more levels of operational discipline control in the use of TMMs – the authority to operate, fitness to operate and operating compliance – must also be considered. 

“If interventions at these six levels still cannot adequately mitigate the significant risk, then the mine must move on to consider the collision avoidance options at levels 7, 8 or 9,” he says. “At Level 7 the PDS will provide proximity awareness by alerting the driver, at Level 8 the system will advise on action to be taken, and at Level 9 the system will slow or stop the machine through engineering control.”

Assisted by the TMM operating scenarios outlined by the Earth Moving Equipment Safety Roundtable (EMERST), mines must be able to provide PDS suppliers with a tabulated scope of what they require. Once a supplier has provided a credible proposal in response, he urges mines to effectively test the solution before making a final decision. 

“The process of installing PDS systems in a mine TMM fleet, and ensuring that operators use the system well, must also be well planned and carefully rolled out,” he says. “The Booyco Integrated Approach includes the technical collaboration with OEMs and on-mine staff, and working closely with operators and management alike to ensure their buy‑in and co-operation.”

Client Focus

BRAVO PUMP PUSHES OUT CONTENDERS IN DENSE SLURRY WORK

Competitors are feeling the heat from the hard-working Grindex Bravo 600 submersible slurry pump, which has replaced under-performing products at two mine sites in Limpopo and North West provinces recently. 

The attraction, according to Jordan Marsh, sales manager at Integrated Pump Technology, has been the Grindex Bravo 600’s reliability and efficiency. This is due largely to its innovative cooling jacket between the outer casing and the motor.

“Mines have a frequent requirement for a hard-working pump to transfer slurry from process tanks, where levels change quickly and the material often becomes quite viscous,” says Marsh. “In these dry-bed applications, many pumps struggle with the density or even burn out when no longer submerged.”

The Grindex Bravo 600, though, has proven ideal for these applications, being supplied in South Africa as standard with a glycol-filled cooling jacket to keep its temperature down. This allows it to function reliably even when exposed above the slurry level.

“Plant operators are not always able to be present to check the levels in these tanks, or to add water to dilute slurry, so the specific gravity of the material can rise considerably,” he says. “This is where the Grindex Bravo 600’s agitator comes into its own, agitating the solids into suspension for easier removal. It even handles particle sizes up to 40 mm.”

To demonstrate the pump’s performance under these arduous conditions, Integrated Pump Rental offers mines a trial unit to run over an extended period. These tests are now resulting in purchases, says Marsh, after the customer is satisfied that the pump delivers. Both the impeller and casing are manufactured from hard iron, making for a robust product with long working life. 

“This 22 kW pump also punches above its weight in terms of output, achieving the same performance as our competitors’ 30 kW pumps,” he says. “This makes the solution energy efficient, saving mines on electricity costs.” 

Integrated Pump Technology has been distributing Grindex pumps in sub-Saharan Africa since 2014. So confident is the company about these advanced workhorse pumps, that the company offers a 30 month warranty on the units. Its well-equipped engineering facility in Jet Park undertakes maintenance and repairs to OEM standards.

Client Focus

PUMPING RESPONSIBLY THE ONLY WAY TO CONSERVE GROUNDWATER

As South Africa increases its use of boreholes to meet growing water needs, users must pay more attention to monitoring and controlling how much groundwater they pump or these resources could be rapidly depleted.

This is according to Stephan Venter, Grundfos product manager water utilities for India, Middle East and Africa, who has been extensively involved in providing pumping solutions for borehole users. 

“The main risk when municipalities, businesses or households make use of groundwater resources is that their extraction from boreholes could exceed the recharge rate of the aquifer,” says Venter. “To avoid this, users need to gather a great deal of information from the start – it’s more than just drilling and pumping.”

An important aspect of ensuring the sustainability of a borehole, he says, is the correct sizing of the pumping infrastructure. This requires data including the borehole’s safe yield, the dynamic water level, the required lift above ground, discharge ratio, friction loss in piping, flow demand and well size. 

He notes that while larger water projects will usually employ the services of a qualified hydrogeologist to generate the necessary data on the aquifer, many smaller users simply proceed with minimal information. 

“This makes it difficult to put the borehole on a sustainable footing,” he says. “Lack of investment in the monitoring equipment also creates challenges in controlling the water abstraction adequately.”

He highlights the importance of taking a conservative view on what levels of extraction the aquifer can accommodate. Even when yield testing is conducted, for instance, there could be other users of that particular aquifer who are not pumping at the time of the tests – leading to an over-estimation of yield capacity.  

“Just to be safe, I tend to advise the user to size their pumping equipment at only 50 to 60% of the borehole’s safe yield,” he says. “This reduces the risk of over-pumping, through which they could possibly even lose this valuable groundwater source altogether.”

There is no substitute for constant monitoring, however, and Venter emphasises the value of digital technology in collecting and transmitting data to keep users informed. Many users still use a manual inspection method to check the level of the borehole and the condition of the pump, but the most effective way is through electronic equipment linked to online platforms.

“This provides updated information at the click of a button, either through a SCADA system for larger users, on a standard computer or even on a mobile phone,” he says. “Monitoring and measuring our groundwater resources is vital in a dry country like South Africa, especially as we work towards becoming more responsible water users.”

Further challenges for borehole users include the unreliable power supply and the rising cost of the electricity required to pump water. Fortunately, solar power generation technology has improved in leaps and bounds, says Venter, and has been well leveraged by borehole pump manufacturers. 

“Solar power now allows water to keep flowing even when mains power goes down,” he says. “The development of high-efficiency pumps – combined with technology like permanent magnet motors and variable speed drives – can reduce pumping costs and ensure constant supply.”

He says that specialised software developed by Grundfos – the world’s largest pump manufacturer – even allows users to go online and select the ideal pump model to suit their borehole specifications, helping to make the most responsible use of the country’s scarce groundwater resources.

Client Focus

DRY-TYPE TRANSFORMERS FROM TRAFO IDEAL FOR COAL MINE

Trafo Power Solutions has customised two dry-type transformers for a coal mine in South Africa’s Limpopo province, allowing the units to be fitted into existing enclosures while meeting the customer’s demanding duty requirements.

“While we would normally supply the transformer together with its enclosure, we are also able to design the solution according to the dimensions available on site,” says David Claassen, managing director of Trafo Power Solutions. 

This required one of the transformers – a specialised 3900kVA unit – to be copper-wound to achieve a smaller footprint suitable to the space constraints without compromising the technical performance. With 11kV capacity on the primary windings, this transformer included four separate secondary windings – for 1810V, 1515V, 1360V and 1210V output respectively. 

“Being located outdoors on a coal mine, the transformer had to be well protected from fine dust and moisture, requiring a specially designed IP54 enclosure,” says Claassen. “At the same time, the transformer’s large size meant substantial heat loss, which needed to be extracted from the enclosure. The design therefore included an air-to-air heat exchanger to recycle cool air in a closed loop.”

The second transformer supplied to the mine was a 1600kVA unit for indoor application, stepping down from 11kV to 550V. Working closely with transformer repair experts Koratech Services, who applied certain modifications to the enclosure, Trafo Power Solutions was able to meet the dimensional and electrical requirement of the application – complete with control and protection system.

“Underground mining often presents space constraints which have to be considered in the design of the transformer or the miniature substation,” he says. “With our expertise and our strategic partnership with leading Italy-based manufacturer TMC Transformers, we can readily cater for these conditions.”

He notes that Trafo Power Solutions also supplies dry-type transformers to the marine industry, which requires not only that transformers can be safely employed indoors, but that they often be accommodated in cramped spaces. This experience enhances the company’s technical capability in underground mines. 

Claassen highlights that both transformers were ordered during the tight Level 5 Covid-19 lockdown in South Africa. Despite similar restrictions in Italy, TMC Transformers proceeded with manufacturing, running a 24-hour, three shift operation to ensure the required social distancing. 

“The high level of collaboration with our strategic partner allowed us to design, build and supply the transformers despite the Covid-19 disruption in 2020,” he says. 

Claassen says the dry-type transformer is ideal for both hazardous and non-hazardous areas of coal mines, as the absence of oil as a coolant makes the solution much safer. There is also much less maintenance required on dry-type transformers.  

Client Focus

POPULAR VSI CRUSHER JUST GOT EVEN BETTER

Continually advancing its crushing technology, Pilot Crushtec International has released its new Pilot Modular VS100 vertical shaft impact (VSI) crusher for tertiary and quaternary applications.

The Pilot Modular VS100 is a remodelled and improved version of the company’s popular entry-level Pilot Modular AC06 VSI crusher, according to Francois Marais, sales and marketing director at Pilot Crushtec. The AC06 has, for over 25 years, been successfully serving the aggregate and mining sectors with hundreds of units in the field both locally and internationally. 

Advanced materials and manufacturing methods have enhanced the Pilot Modular VS100, while it has retained the functionality and reliability of the tried-and-tested AC06 model. The versatile crusher is used mainly for producing sand and fines, and for enhancing the quality of aggregate.

“Among the features of the new VS100 are elements that make for a safer working environment,” says Marais. “These include a new inclined staircase, and a three-sided platform that is both non‑slip and chemical resistant.”

He emphasises that this high performance machine is packed with years of experience and know-how. The hydraulic pack both opens and automatically rotates the lid, revealing the modular rock chamber and rotor. The jib crane is installed as a standard item, for safe removal of the rotor. 

“The modular rock chamber allows you to go from autogenous crushing to an anvil ring crushing configuration, and is designed for efficient rock-box build-up,” he says. “The VS100 is also future-proof – with the option of two rotor sizes, five motor sizes, five rotor speeds and a rotor by-pass system.”

Marais explains that these options allow plant capacity requirements to be optimised with economical power consumption, making the unit versatile enough to allow upgrades as plant production requirements increase. 

“Once you start the crusher and the material pours into the newly designed omni-directional feed chute, you notice how smoothly the new advanced vibration isolation keeps the plant running smoothly,” he says.

The new-generation triple bearing, grease lubricated cartridge has an optional Auto Lube system to facilitate regular lubrication for added reliability, while the modular serviceable rotors reduce operational costs. Once the worn wear parts have been replaced – and correct tip material selected to suit the stone – the rotor can be balanced using the balancing kit provided. Pilot Crushtec SupportLink technicians are available to train customers’ maintenance teams during commissioning, ensuring smooth and cost-effective operation into the future.

“Overall, the new Pilot Modular VS100 is the complete package,” says Marais. “With its improved safety features for overall compliance, this brand new design allows operations to increase tonnages from 10 tph to 100 tph, depending on the application.” 

He also points to the unit’s ease of maintenance, made possible by the smart design and the simple operations of the crusher. These factors make the new Pilot Modular VS100 a wise and operator-friendly investment for any operation making use of VSI crushing. The skid-mounted module requires only a level compact surface for installation, and no civils infrastructure.

Client Focus

ZEST WEG GIVES MOTOR USERS ANOTHER EFFICIENCY BOOST

In the face of rapidly rising electricity costs in South Africa, Zest WEG is phasing in IE4 super‑premium efficiency motors in its WEG W22 range from April 2021 – which will save on customers’ bottom lines and help reduce the load on the national grid. 

According to Fanie Steyn, electric motors manager at Zest WEG, 2021 will see local energy prices rising above R1/kWh for the first time. This makes it the ideal time for the introduction of WEG IE4-rated motors, which will be available in the size range between 37 kW and 375 kW.

“Unlike many countries around the world, South Africa has not regulated the use of energy efficient motors at the level of IE2 or IE3,” says Steyn. “Nonetheless, we have taken the proactive step of making the IE4 level of efficiency available to customers at no premium on the IE3 units.”

Some years ago, Zest WEG introduced its WEG IE3 motors to the country at little or no additional cost relative to its IE2 motors, with the same goal in mind: making both customers and the country more energy efficient.

Specified under the International Electrotechnical Commission (IEC) 60034-30-1:2014 standard, IE1 refers to standard efficiency and IE2 to high efficiency; the IE3 and IE4 ratings are for premium efficiency and super-premium efficiency motors respectively.

“The efficiency of 96.3% on an IE4-rated 110kW motor, when compared to 94.1% on an IE1-rated motor, can save users hundreds of thousands of rand in energy costs over a 10 year period,” he says. “Not only will these IE4 motors be more cost effective to run, but they have been designed with a number of new features that bring considerable benefits.”

Steyn emphasises that WEG IE4 super-premium efficiency motors meet IEC efficiency levels when running on 50 to 100% of load; efficiency is kept constant, which saves energy and ensures minimal losses through various loading points. The innovative frame design also allows maximum heat dissipation.

“Motor frame design plays a crucial role in thermal performance, as it is responsible for the outward transfer of heat generated inside the motor,” says Steyn. “Running cooler means that our motors have increased life spans, allowing Zest WEG to offer a five year guarantee on our WEG W22 electric motor range.”

The motors’ increased mechanical rigidity – achieved by integrating the front and rear feet sides – affords easier installation, higher mechanical stiffness and improved distribution of the mechanical thrust imposed by the load.

“As a first of its kind, our flexible terminal box mounting means reduced inventory and quicker modification,” he says. “The terminal box can be rotated in 90° increments to facilitate supply cable connection orientated to the front, rear, top or either side of the motor.”

In addition to the benefits brought by WEG super premium efficiency motors a substantial increase in energy savings can be reliably achieved using WEG Variable Speed Drives (VSDs), which comply with the European Extended Product standard EN50598. This ensures the system efficiency of the motor and VSD combination. As an additional feature, WEG VSDs have energy savings settings which can be user activated, achieving an automatic saving under any reduced load conditions.

“We are excited to build on the phenomenal reputation of the existing WEG W22 electric motor range by offering an even more efficient motor that is truly “next level” state of the art in electric motors, having the same rock solid quality and reliability,” Steyn concludes.

Client Focus

GRUNDFOS PUMP SUPPORTS JOJOBA GROWERS IN NAMIBIA

Grundfos approved distributor ConServ Engineering Services has supplied an innovative water solution to provide sustainable employment in agriculture in rural Namibia. 

Approached by the aid project Jojoba For Namibia Trust, the company selected a Grundfos submersible groundwater pump in a water supply design for a jojoba plantation in the Omdel Dam area north-east of Hentiesbaai. 

Although the jojoba is the ideal desert plant and only requires a little water, one of the biggest challenges in the desert environment of Namibia is the lack of water. Where the plants can be successfully grown, they bear nuts once a year which can be pressed for oil of export quality. 

“In the first phase of the water supply project in October 2020, we installed a Grundfos SP7-37 pump into the jojoba plantation’s borehole,” says Mark Riehmer of Conserv Engineering Services. Drawing on renewable energy from the sun, the pump is powered by 18 solar modules which the company also installed, along with an RSI 5500 inverter. This phase will pump water about 1,5 km to the first storage tank, with a pipeline incline of a couple of metres. 

“This system has been designed in such a way that the yield of the pump can be increased in future to supply more storage tanks along a 5 km pipeline, with a total elevation of 80 m,” says Riehmer. The final layout of the system will include 36 solar modules and will have a yield of 50 m³ per day at the last water point. 

The Jojoba For Namibia Trust reported that they now have more water than they expected, and can start expanding the plantations faster than they had planned. The trust supports the establishment of jojoba plantations in the communal areas of Namibia, focusing on providing the rural population with a sustainable business model and employment opportunities. The oil that is pressed from the nuts is promoted as an antibacterial agent which is rich in pro-vitamin A, E and B. It is exported to Europe, mainly for use in the cosmetic industry.

“With this sustainable water solution, the jojoba plantation and the local community will benefit for decades to come,” says Riehmer. “A future of economic empowerment opportunities has been created for the coming generations.” 

Client Focus

CONCOR COMPLETES RADISSON RED HOTEL IN ROSEBANK

Concor has successfully completed South Africa’s second Radisson RED hotel – this one is situated in the vibrant Oxford Parks mixed-use precinct in Rosebank, Johannesburg.

The upmarket 222 room hotel has been designed – like all Oxford Parks Precinct buildings – to meet a minimum five-star Green Star rating. It will open its doors to guests in June, two months after Concor handed over the building in April 2020. This follows the success of the country’s first Radisson RED hotel – located at the Cape Town Waterfront – which opened in 2017.

Concor took the project through to furniture, fitting and equipment (FF&E) stage, including beds, chairs, television sets and the physical backbone for WiFi connectivity, according to Martin Muller, contract manager at Concor. 

“The basements for the building were completed as part of the first two phases of the Oxford Parks Precinct, and construction began in October 2019 with the superstructure, from ground floor up,” says Muller. Although the Covid-19 lockdown delayed the project somewhat, construction progressed well on this fast track project. A combination of good planning and full resourcing made this possible, he says, with about 500 people on site at peak including contractors. 

Comprising seven levels on top of a ground floor, as well as a roof level for plant and services, the building is a concrete structure based on post-tensioned slabs with grids to suit the room sizes. At the core of the building are four lifts: a goods lift, a fireman’s lift and two lifts for guests.

The ground floor includes the reception, restaurant, kitchens, back-of-house facilities and conference rooms, with the first level housing the management offices, staff facilities and more conference space. Floors two to six each comprise 40 rooms, while on the seventh floor there are just 22 rooms sharing the level with a pool, terrace bar and gym. 

“The compact design means that the majority of plant is located on the roof – the eighth level – including water tanks and all the heating, ventilation and cooling (HVAC) systems,” he says. 

A curtain-wall system of aluminium frames and double glazed windows characterises the east and west sides of the hotel. On the north- and south-facing sides is a facebrick patterned façade with punch-out square windows.

“Most of the internal partitions are constructed with dry-walling materials of high acoustic and fire-rated properties,” he says. “The specifications for these are highly technical, to avoid any noise transfer from room to room despite the compact design.”

Concor’s work was guided by two sets of specifications, one for back-of-house and another for front-of-house, he notes. The base build spec was provided by dhk Architects, while the interior design spec for the rooms was by Source IBA. 

“Keeping a quality building process on track demands a constant focus on information sharing with consultants and subcontractors alike,” says Muller. “This meant weekly meetings to align our building plans with any design adjustments, so we could avoid rework that could have slowed the pace and added to the cost.”

The speed of the project was enhanced by having one tower crane on site, facilitating the work of all trades through the quick delivery of concrete and other materials to the various levels. He highlights the importance of the quality assurance and quality control (QA/QC) teams that followed production and streamlined the snagging process, so that the fit-out specialists could move in to progress the rooms. 

“This allowed the production workers to fully complete their tasks before the entry of plumbers, tilers, painters, joiners, electricians and other finishing trades,” he says. Sequencing was conducted in an east-to-west direction, and these teams completed eight rooms at a time. 

The Radisson RED project also provided an opportunity for Concor to conduct enterprise development among selected subcontractors. Working with three local small businesses, Concor was able to transfer skills in 18 of the required trades, including brickwork, painting and final handover preparation.