Tag Archives: Weir Minerals Africa

Namdeb receives the Linatex treatment at Sendelingsdrift

The installation by Weir Minerals Africa of a Linatex® 808 hard wall rubber hose with wear indicator system is, Weir says, reducing downtime and operating costs at Namdeb’s Sendelingsdrift treatment plant in Namibia.

Sendelingsdrift was previously having to change out the incumbent competitor’s rubber hoses every four weeks due to excessively high wear rates. In addition to the ongoing downtime, the plant also risked losing concentrate due to the hose failures. As the concentrate media contains diamonds, additional security was required when dealing with hose failures that result in concentrate leakage – adding to the operating costs.

The Weir Minerals Africa service teams regularly visited Sendelingsdrift to engage with the plant manager, area engineers and other operational staff to get a better understanding of their requirements and problematic applications. After an audit of the site, the team considered all the parameters and proposed a trial of a Linatex 808 rubber hose fitted with a wear indicator system.

The proposed solution would be capable of withstanding the slurry flow rate of 84 litres per second with a slurry density of 2,65 t/cu.m. The wear indicator system installed on the hose would indicate when the hose was nearing the end of its life; no physical inspections would be necessary. In addition, Sendelingsdrift would save the cost of additional security requirements by eliminating premature hose failures.

Sendelingsdrift agreed to the proposed trial, and the Weir Minerals Africa service team conducted weekly site visits to inspect the hose and the wear indicator system. While the competitor hose generally failed after delivering 32,000 t of ore, the trial showed that the Linatex 808 rubber hose surpassed 162,000 t, according to the company.

The hose lasted seven-and-a-half months before being replaced – more than six times longer than the competitor’s hose, representing a significant cost saving for the customer. The Linatex rubber hose processed over 2.5 Mt of concentrate and a similar volume of slurry during this time.

Designed for dual delivery and suction applications, Linatex 808 rubber hose can be custom manufactured to any size and is available with a range of flange types, Weir Minerals says.

Weir Minerals Africa putting newly designed vibrating screens to the test

Weir Minerals Africa, having over the last 40 years proven the credentials of its Enduron® range of vibrating screens, is now locally designing and manufacturing new-generation linear motion vibrating screens.

One of these new, modern screen designs is part of a recent Weir Minerals Africa complete comminution plant contract for a South Africa mining project. The scope included two crushing stations, a screening station and all the related feed chutes, bins and conveyors.

According to Christian Stehle, Head of Engineering at Weir Minerals Africa, the company’s design capability provides the flexibility to produce vibrating screens to suit each customer’s plant layout. At the same time, the designs will optimise cost, efficiency and performance. South Africa also hosts Weir Minerals’ global screening and separation technology group.

“This expertise ensures that our robust Enduron vibrating screens provide exceptional classification and dewatering screening performance,” Stehle said. The screens are deployed in a wide range of minerals processing applications.

He noted that vibrating equipment is generally more challenging to design than static equipment due to the high frequency cyclic loading to which the machines are subjected.

“The final design must address key criteria like screening efficiency, throughput and loading, while still operating within the acceptable fatigue life limits of the materials of construction,” he said.

Stehle highlighted that the use of finite element analysis (FEA) tools allow engineers to optimise screen life by obtaining the stress and deflection levels in the equipment and applying the appropriate structural design and utilisation of materials in the areas experiencing high stresses.

“Traditionally, screen designs used to be heavier in an effort to extend the life of the equipment,” he said. “Using FEA tools during the design stage allows us to retain structural integrity while actually reducing the overall weight of the machine.”

While there are areas of high stress on the equipment that need more strength, technology tools indicate where lower stresses occur. In these areas, less steel can be used to make the structure lighter, according to Weir Minerals Africa. Leveraging this technology, the weight of some new-generation screens has been cut by up to 15%, the company said.

Stehle noted that Weir’s Synertrex™ IoT platform can also be applied to monitor and improve the performance of the company’s vibrating screens. Synertrex technology is an industrial internet of things system that allows operators to monitor every aspect of their equipment’s operation, to prevent problems and increase throughput.

Weir Minerals Africa underlines benefits of Linacure wear parts

Weir Minerals Africa says its Linacure® 40 natural rubber compound is engineered to provide superior wear performance to counter fine slurry abrasion.

Locally manufactured by the company, this uncured compound is suitable for applications where hot bonding is the preferred method of installation, the company said.

Using the same formulation principles employed in Weir Minerals standard Linatex premium rubber, Linacure 40 was created to provide a differentiated wear performance when compared with competitor uncured natural rubber products, according to Weir.

“Worldwide tests have confirmed the performance of this wear lining which is rated at 40 IRHD against the ISO 48-2010 standard,” Weir says.

It offers a tensile strength of 215 bar (3,118 psi) and is suitable for use in operating temperatures from -40 degrees centigrade to +70 degrees centigrade, the company added.

Linacure 40 is manufactured in sheet form of varying thicknesses, allowing it to be cut or configured into any shape the application may require, according to Weir, adding it is lighter and more flexible than other wear liner materials such as steel and ceramics. The latter trait makes it easier to handle and install, Weir said.

Typical applications for the product would be to line pipelines, chutes, tanks and hoses.

Weir Minerals Africa optimising pump performance for filter presses

With mining companies focused on reducing and recycling as much water as possible while recovering valuable minerals and metals, filter presses are becoming a much more common sight in the concentration process.

Weir Minerals Africa says these “mission-critical” filter presses demand a carefully selected pump to ensure optimal performance and uptime.

Marnus Koorts, Product Manager for Slurry Pumps at Weir Minerals Africa, says the high pressures associated with operating a filter press often lead the pump to underperform.

“The operation of a filter press involves a wide spectrum of pressure and flow conditions within each cycle,” Koorts says. “This ranges from high-flow, low-pressure conditions when slurry is initially being pumped into the press, to low-flow and high pressure when full.”

He emphasises it is not enough to simply specify a pump for the average of this range of conditions. Rather, it is vital to establish the minimum and maximum values on the spectrum, and to specify accordingly.

“Filter presses in the market can demand pressures of up to 45 bar,” he says. “In many cases, therefore, the application requires high-pressure pumps such as the Warman AHPP high pressure range.” These pumps offer multi-stage high pressure operation to 1,000 psi and are used in slurry transportation and tailings management operations.

Koorts continued: “Where lower pressure requirements are present, the newer technology of the Warman WBH could be used as it is generally a more efficient pump with longer wear life of spare parts.” The Warman WBH pumps, also used in slurry transportation and tailings management applications, come with a wide variety of impellers and shaft seals and maintains efficiency through ‘one point adjustment’ during the wear cycle, according to Weir.

Failure of pumps to deliver enough pressure to a filter press results in the solid-liquid separation process being inefficient, according to Weir, with the selection of the right pump an important starting point in ensuring optimal operation.

The next key aspect of the customer’s selection, Koorts says, is the choice of sealing arrangement. This aspect of the pump can often lead to issues in the plant, when valuable product is lost through leakage.

“An expeller seal is not usually recommended, as the pressure it generates to seal the pump is generally not sufficient in a filter press application,” he said.

Weir said: “The stuffing box option can be used under certain conditions. However, the pressure of the surface water needs to be higher than the pressure inside the pump. This means that it would usually be suitable on a low-pressure pump for a low-pressure filter press.”

Koorts added: “When the filter press requires a higher pressure, then the plant will have to provide a water line with a higher pressure to feed the gland, or it will not seal properly.”

The preferred sealing option is a mechanical seal for these applications. While this is more costly, it offers substantial savings by preventing product being lost and downtime being incurred, according to Weir.

A further consideration is the level of corrosive aspects of trace elements in the slurry. This can lead to rapid corrosion of mild steel pumps. This is why many applications require stainless steel options.

Comprehensive technical backup needs to underpin each step in this process, Koorts said. For Weir Minerals Africa, this begins with its local manufacturing process, which includes foundries for casting components, through to local componentry manufacture and assembly capability.

“This quality control and capacity feeds into our spares availability and service exchanges for refurbished pumps,” he says. “The result is quick supply through our strategically located branch network with 12 offices in South Africa and eight through the rest of Africa.”

Weir Minerals Africa on the importance of application-specific valves

Weir Minerals Africa has stressed the importance of using quality original equipment manufacturer (OEM) products “engineered specifically for their application” when it comes to using valves in abrasive and corrosive slurry conditions.

Without such components, valves can be quickly worn out and costly downtime can occur, the company said.

Ronald Govender, General Manager – Process Equipment at Weir Minerals Africa, said: “With our comprehensive range of slurry valves, we can help customers select the right equipment to suit the pressure of their system, the chemical make-up of their slurries, and the physical nature of the solids they process.

“We can provide the right wear options, actuation mechanisms and control accessories that will ensure optimal plant uptime.”

Weir Minerals’ Isogate® range of slurry valves is proven to be reliable and versatile, according to Weir, operating under wide pressure and temperature ranges. “For longer life, valve sleeves come in a variety of materials including genuine Linatex® premium abrasion-resistant natural rubber. To reduce downtime and overall cost of ownership, all wear parts are easily replaced in the field,” the company said.

The range includes mechanical pinch valves, with open or closed body, and pneumatic pinch valves with one-piece sleeve or two-piece liner. Isogate knife gate valves are known for their heavy-duty performance, even in coarse slurries, with pressure ratings from 10 to 51 bar, Weir said. These are uniquely designed with both ease of maintenance and low overall cost of ownership in mind and are engineered to handle the harshest and most abrasive process flow conditions, according to the company.

Weir Minerals’ check valves are single, non-return units that benefit from 20 years of in-field experience in the most arduous slurry applications, Weir said. Within this range, Autoball® valves, which are actuated with differential pressures, enable quick changeover between duty and standby pumps.

“An exciting addition to our offering is the Delta Industrial™ range of knife gate valves, which set the standard for high performance in slurries,” Govender said. “These valves guarantee zero leakage, due to their unique transverse seal and shear gate design.”

The design protects the primary elastomer seal from the slurry flow to avoid wear, while a precision-machined metal seat provides a secondary seal. “The transverse seal features an upper and lower scraper, with an elastomer that is energised by a pliable compound – even while the valve is in service.”

Designed for the most demanding processes, Delta Industrial valves have been in use for over two decades in mill circuits, tailings transport, mineral separation and leaching applications for slurries up to 120 bar working pressure.

“We bring a full basket of valve solutions to customers,” Govender said. “Other valves in our liquid service range include butterfly, diaphragm, globe and trunnion-mounted ball valves.”

ERP system ups inventor accuracy at Weir Minerals Africa’s Kitwe facility

Weir Minerals Africa’s newly upgraded Kitwe facility in Zambia, its hub for central and east Africa, is benefiting from the use of an enterprise resource planning (ERP) system that has seen inventory accuracy rates rise, according to the company’s Luhann Holtzhausen.

The branch officially opened in early 2018 and boasts a state-of-the-art logistics and supply chain management systems to match those at Weir Minerals Africa’s main distribution hub in Alrode, near Johannesburg, it said.

Luhann Holtzhausen, Weir Minerals Africa Supply Chain Director, said: “Our Kitwe branch now has a 100% location-controlled warehouse that runs off our ERP system with Wi-Fi-enabled scanners in place. This has resulted in the achievement of inventory accuracy rates in the high 90s.

Holtzhausen continued: “The technology and technical capacity in this facility enables us to pick and bin items in real time. This will match any other system that customers may have seen globally and is also a benchmark within Zambia.”

The new warehouse is all under one roof, with high visibility through natural and artificial lighting, where every product is clearly labelled with bin location and barcodes for easy tracking, Weir said. Shelving of up to three metres high keeps all items neatly stacked, easy to identify and quick to retrieve.

“The right goods in the right quantity in the right place means that when a customer asks for an item, we know that we have it and can find it without delays,” Holtzhausen said.

As part of the company’s operation-wide system, the stockholding of the Kitwe warehouse can be viewed in real time by the supply chain management team in Johannesburg. Holtzhausen emphasised the importance of the ERP system’s ability to track trends in customer usage in a systematic and methodical manner, to avoid any stock-outs on mine sites.

Lack of timeous access to spare parts and equipment can be costly in terms of operational downtime, particularly at remote mines that take time to reach, Weir said.

“In addition to the high accuracy of our data on warehouse inventory, our systems also give us end-to-end velocity measurement to monitor the flow of goods from receipt at our warehouses to the actual time of delivery at the customer’s location,” Holtzhausen said.

Weir Minerals Africa has 75 stocking locations across the southern and central African region, and ships nearly 100,000 items each year from its main distribution hub in Alrode.

Weir Minerals Africa’s supply chain efforts providing miner payback

Weir Minerals Africa has been upgrading its supply chain system over the past four years and the company says its mining customers are feeling the positive effects.

According to Weir Minerals Africa’s supply chain director Luhann Holtzhausen, the company ships almost 800,000 bespoke items each year from its main distribution hub in Alrode, near Johannesburg, South Africa.

Leveraging both modern technology and an innovative management approach, it has raised its warehouse stock accuracies to 98% over the past four years, above the global benchmark of around 95%, the company said.

Holtzhausen said: “Our streamlined supply chain management ensures 70% of our products and components are delivered within two weeks of a sales order being received. Our inventory accuracy has also raised the on-time delivery performance over the last year above 90%.”

Between 3,000 and 5,000 parts are shipped each day from the Weir Minerals Africa Alrode facility. These volumes have grown 20% year-on-year since 2016, which the new systems can still comfortably manage in a single-shift operation, according to the company.

Eleven to 14 super-link trucks, which range in capacity up to 30 t, leave the facility each week to destinations in southern and central Africa. In addition, there are two to four container loads shipped to other destinations by sea.

Holtzhausen said: “Our new systems and processes provide management with real-time visibility of demand and stock in all offices across Weir Minerals Africa’s 75 stocking locations. This also gives us end-to-end velocity measurement to monitor the flow of goods from receipt at our warehouse to the actual time of delivery at the customer’s location.”

The same systems are installed at the company’s newly upgraded Kitwe distribution facility in Zambia, streamlining its capacity as a strategic distribution hub for central and east Africa, Weir said.

The benefits for customers of these improvements in supply chain efficiency include reduced lead times and less possibility of stock-outs on customer’s sites, the company said. “This, in turn, gives mines improved availability of equipment, less downtime and higher productivity.”

Holtzhausen concluded: “A significant advantage of optimal supply chain management is that customers gain confidence in our ability to deliver. This means that they can start holding less stock themselves and free up substantial amounts of their working capital.”