Tag Archives: pumps

Weir Minerals confronts froth pumping problems

As miners look to reclaim more minerals from the flotation process through froth pumping they are potentially exacerbating existing problems in their circuit design, according to Les Harvey, Regional Product Manager for Slurry Pumps at Weir Minerals.

Mining companies are making these moves to counteract declining ore grades, but, occasionally these techniques are deployed without making allowances for the design of the mine’s froth pumping equipment.

Froth pumping remains one of the most complex engineering challenges in minerals processing, as air management issues in the hopper, sump and pump itself lead to inefficient pumping, increased maintenance and even lost product, according to Weir.

“We’ve started to notice a pattern among our customers who are having trouble with their froth pumps,” says Harvey. “By using more flocculants and other chemicals designed to improve mineral recovery, they’re exacerbating existing problems in circuit design and reducing the returns they’re looking for.”

Close examination of the froth’s makeup and physical qualities is often needed to resolve issues. Ensuring operators’ froth handling equipment adheres to best design practices is an important first step in resolving problems, according to Weir.

Maintaining pressure in the pump

The key challenge in froth pumping is dealing with air in the pump itself, as it tends to naturally centrifuge into the impeller’s eye where it builds up into an ‘air lock’ which impedes the movement of slurry through the pump, Weir said.

In addition to reducing the pump’s efficiency, the air build up in the pump will reduce the flow through the pump and increase the slurry level in the suction hopper. The increased slurry level may push the pocket of air through the pump, causing surging and excessive vibration which can damage the pump bearings, impeller and shaft.

“The best way to manage air in a froth pump is to invest in a froth pump with a Continuous Air Removal System (CARS), which we have in our Warman AHF, MF and LF pumps,” Harvey says.

CARS allows air to move from the pump’s impeller eye to an air collection chamber in the back through a vent hole in the impeller. From that chamber, a flow inducer removes the air from the pump through a vent pipe.

Harvey said: “It’s also important to position the pump’s discharge pipe at the top of the pump, or at a 45° angle as this will give air trapped at the top of the casing a way to escape the pump.”

Solving problems in the sump and hopper

A persistent problem Weir sees is when hoppers designed to meet the demands of slurry pumping are used in a froth pumping application, Harvey said. “Slurry hoppers require turbulence to prevent the mineral content from settling, while turbulence in a froth pump prevents the air from escaping and leads to blockages.”

Tanks designed for froth pumping promote continuous circular movement, where solids and liquids are sent to the outside of the sump for further transport while air centrifuges into the centre where it can be removed. This ‘whirlpool’ movement can be encouraged by introducing the slurry from the top of the tank at a tangential angle, according to Weir.

Conical designs, rather than those with a flat or rounded floor, further improve the flow of minerals and froth into the pump, the company added.

Smooth sailing from the tank to the pump

To prevent blockages, the intake pipe which links the tank to the pump should be large diameter and slope downwards towards the pump, according to Weir. This design allows escaped air to separate and travel back up the pipe where it can escape from the sump, rather than build up into blockages.

Harvey said: “The shorter your intake pipe, the harder it is for blockages to build up. However, in addition to a maintenance spool and isolation valve, it’s a good idea to leave enough space for a water injection port, which is useful for flushing out any solids build up.

“To make maintenance easier, a dump valve can be included on the suction side of the pump, between the pump and the isolation valve. This will allow you to drain slurry from the pump and discharge pipe system when stopping the pump for maintenance.”

Understanding tenacious froths

Froths are often classified as either brittle – with large air bubbles that break easily – or tenacious – where air forms tight bubbles around minerals and is difficult to separate. Froth being more tenacious than was accounted for is a frequent cause of blockages as air cannot effectively be removed, Weir says.

Harvey said two things are happening in the market today: One, mine operators are grinding the product much finer than before to liberate more from the waste rock. Two, they’re using flocculants that produce much smaller bubbles which lock up the air a lot more than brittle froths.

“We’re working together with customers to find ways to manage these more tenacious froths, by looking at their circuit design and dealing with areas where the air could accumulate and block the system, paying particular attention to their pumps, pipes and sumps,” he said.

Babylon Pump & Power adds Queensland hub to Western Australia base

Babylon Pump & Power has established a rental service base on the East Coast of Australia with the completion of its acquisition of Primepower Queensland.

The company announced the deal with the leading diesel engine specialist back on July 26, saying it would pay for the company with a mixture of cash, shares, delayed performance payments and assumption of debt.

Primepower was founded in Mackay, Queensland, in 2004, and has a client base including Peabody, Fortescue Metals Group, BHP Mitsubishi Alliance, Anglo American, Wesfarmers and Minerva.

The Primepower buy, according to Babylon, offers:

  • Geographic and technical expansion;
  • Diversification of commodity exposure;
  • Purchasing power and contract synergies;
  • East coast platform to introduce rental services; and
  • Workshop flexibility with no additional corporate overhead.

Post-acquisition, Babylon will be one of the largest independent and diversified engine re-builders in Australia, poised for growth in specialist rental nationally, with a focus on Australia’s two key mining states, Western Australia and Queensland, the company said.

Integrated Pump Rental up for southern Africa pit dewatering challenge

As open-pit mines continue to get deeper with the maturing of operations, pit dewatering is becoming more vital, with ground water not only posing an operational challenge but also a potential safety hazard if not attended to appropriately.

In this scenario, it is not a case of one pump fits all dewatering application requirements and it is advisable to deal with a reputable pump supplier to ensure the most appropriate solution is selected, according to Integrated Pump Rental.

Lee Vine, Managing Director of the company, said each application requires a site-specific solution.

“There are numerous options available in terms of the actual pump and ancillary equipment, as well as the choice between rental and outright purchase,” he says. “The differentiator that our team offers is the ability to assess a given application and provide a pit dewatering solution with the correctly sized pump.”

There are several factors that can have an impact on the pump selection, and this includes available power sources; the volume of water to be pumped; and the condition of the dirty water, including size and type of particles in the water.

“What adds complexity to pit dewatering applications is that, in many cases, the need to dewater a pit can be urgent and customers are forced into making an incorrect pump selection or tying themselves into a contract that does not work in the longer term,” Vine says.

While the decision to hire or purchase is an important commercial one, so is the actual selection of the pump itself, he said.

“If the pump is not sized correctly for the dewatering application at hand, it will not perform as required. This, in turn, leads to further operational challenges including production losses and sometimes even the need to change the pump resulting in further costs.”

One of the most important factors to consider is the available energy source. If there is no access to power, options such as diesel-driven or pumps fitted with hydraulic power packs must be explored.

When selecting the pump, it is also important to understand the specifics of the water ingress conditions and whether this is a long-term issue or simply a short-term challenge. This scenario will dictate the pump size, its rated output and what ancillary equipment is required.

As an example, Vine points to a recent dewatering application on a mine in Lesotho where a constant flow of water into the mine’s pit area demanded that water be urgently and reliably pumped out.

Over time the pit depth had increased, and the groundwater level had been exacerbated by the winter snowfall in the highlands of the country. As a result, the total dynamic head for the duties of the installed dewatering pump installation changes and the mine required an urgent solution.

Initially a Sykes XH150 diesel driven pump was deployed, pumping at 120 l/s at 150 m head. Subsequent to this, a second Sykes pump was dispatched to site to ensure the level of water remained at an acceptable level.

With the two Sykes pumps on site, the mine was assured of enough pumping capacity, should the groundwater level increase.

The call from this mine came in and, within 24 hours, the first Sykes pump was installed on site, according to Vine.

“This is very significant, when one considers that the mine is situation some 500 km from the company’s front door and across the border into a neighbouring country.”

Integrated Pump Rental not only rents out Sykes diesel driven pump sets, the company is also responsible for the sale of these dewatering pumps across southern Africa. The robust units are designed for reliable performance, under even the harshest operating conditions, according to the company.

Weir secures largest-ever individual mining order from Fortescue

The Weir Group says it has been awarded a £100 million ($123 million) order to provide industry-leading energy saving solutions to the Iron Bridge magnetite project, a joint venture between Fortescue Metals Group and Formosa Steel IB.

The order, which includes a range of Weir crushing and pump equipment including Enduron® high pressure grinding rolls (HPGRs) and GEHO® pumps, will reduce energy consumption and wet tailings waste by more than 30% compared with traditional mining technologies, according to the equipment manufacturer.

The Iron Bridge project, 145 km south of Port Hedland in the Pilbara region of Western Australia, is a $2.6 billion investment in premium magnetite iron ore reserves with annual production, when the mine is fully operational, of 22 Mt/y of 67% Fe concentrate. Delivery of the first ore is expected in 2022.

When the mine build was approved back in April, Fortescue CEO, Elizabeth Gaines, said the innovative design for the project, which included the use of a dry crushing and grinding circuit, “will deliver an industry-leading energy efficient operation with globally competitive capital intensity and operating costs”.

A pilot project to verify the Iron Bridge project design involved processing 1 Mt of ore through a full scale HPGR and air classifier, according to Fortescue.

Weir Group Chief Executive Officer, Jon Stanton, said: “We are delighted to have secured this landmark contract, which is Weir’s largest-ever individual mining order.

“Fortescue challenged us to help create one of the most energy and cost-efficient magnetite ore processing facilities in the world. Our engineers have worked relentlessly to design a solution that is truly innovative – delivering significant energy, water and cost savings. This is a great example of working in close partnership with an ambitious customer who shares our passion for using innovative engineering to make mining more productive and sustainable.”

Ricardo Garib, President of the Weir Minerals division, added: “Our team are really enjoying working with Fortescue. Our engineers relish a challenge and it has been great to work on a project that demonstrates the substantial cost and environmental savings that our range of solutions can offer.

“As more mines look to increase productivity, we look forward to even more opportunities to leverage our combination of passionate people, innovative solutions and comprehensive global service capability.”

Weir’s Enduron HPGRs are increasingly replacing conventional mills in comminution (crushing, screening and grinding) circuits because of their substantially lower energy consumption and potential for significant total cost of ownership reduction, Weir says.

“Not only do they require as much as 40% less energy than traditional alternatives, but their wearable components last much longer and the maintenance time required to replace worn out parts is significantly lower.”

The company outlined the reasons why companies are turning to Enduron HPGRs in a blog post earlier this week.

Vesconite water flingers seal the deal for mining pump manufacturer

Vesconite Bearings has come to the rescue of a southern Africa pump manufacturer looking to improve the performance of horizontal centrifugal pumps operating in mines across the continent.

The company has now received its order for Vesconite low-swell hard-wearing water-flinger polymer bearings for four of its pump sizes.

Vesconite Bearings said the manufacturer found its horizontal centrifugal pumps, as a result of high pressure, had a problem of water escaping from the gland packing – the material that should form a watertight seal around the shaft.

This resulted in dirty water being sprayed on to the non-drive-end bearing assembly and, in turn, seizure, failure, and a high maintenance and down-time cost to replace the bearing assembly.

“The manufacturer designed a water flinger (deflector) solution that would attach to the release collar on the shaft,”  Vesconite Bearings Technical Sales Consultant, Phillip de Villiers, said.

“This would mean that excess water from the gland packing would be deflected with the rotation of the shaft.”

However, the initial solution employed a phenolic laminated material, which was found to absorb water and delaminate.

To eliminate these problems, the company called on de Villiers, who suggested Vesconite as an alternative material that would not swell or delaminate and had the added advantage of being suitable in dirty environments because of its excellent wear-resistant properties.

“Samples were produced and tested and, proving successful, the manufacturer ordered water flingers of various designs for its different pump sizes,” de Villiers said. “The whole process from sample production to first order took three months.”

The pump manufacturer intends to use Vesconite water flingers in all of its pumps, which are used in a variety of applications, according to Vesconite Bearings.

It is active in a multitude of African countries, including South Africa, Zimbabwe and the DRC, in which some of the first Vesconite water flingers will be installed in a dewatering pump in a mine, Vesconite Bearings says.

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.”

Babylon Pump’s business development efforts power up

Babylon Pump & Power Ltd has entered into a conditional agreement for the acquisition of diesel engine specialist Primepower Queensland for up to A$4.2 million ($2.9 million) in cash, shares, delayed performance payments and assumption of debt.

Mackay-based Primepower was founded in 2004 and is a specialist in Cummins engine repairs and rebuilds to the Queensland resources sector, Babylon said, with the acquisition complementing Babylon’s Western Australia-based diesel maintenance division and diesel generated power and pumping rental business.

The company has grown into a highly regarded specialist provider of diesel maintenance to the resources sector with a client base including Peabody, Fortescue Metals Group, BHP Mitsubishi Alliance, Anglo American, Wesfarmers and Minerva, Babylon said. Primepower generated unaudited annual revenue of around A$9.1 million for the year to June 30, 2019, and adjusted net profit of some A$600,000.

“The acquisition is Babylon’s first move into the eastern states and forms part of the company’s growth strategy, and provides an ideal platform to expand Babylon’s successful specialty equipment rental business into the East Coast,” Babylon said.

The acquisition provides Babylon’s Diesel Maintenance division with extra scale, in addition to technical expertise in Cummins engines to complement its expertise in Caterpillar engines, Babylon Executive Chairman, Michael Shelby, said. “[It] will be the perfect springboard to introduce our power and pumping rental offering to the East Coast market,” Shelby said. “The acquisition also provides commodity diversity, exposure to a larger client base, many with national operations, and will deliver a step-change in our operating scale and revenue.”

Shelby hinted that this may not prove to be the end of the company’s M&A efforts.

“The resource services and related sectors remain very fragmented, and it has become apparent that there are a number further potential complimentary acquisitions and new business development opportunities available,” he said. “While focusing on its core business, it is Babylon’s intention to explore thoroughly opportunities to expand in conjunction with its strong organic business growth.”

The consideration is comprised of cash on completion of A$1.7 million (adjusted pro-rata for net assets), A$600,000 in Babylon shares, assumption of a A$500,000 trade finance facility, deferred consideration of A$1 million over two years (adjusted for net asset value), additional deferred consideration of A$500,000 conditional on a revenue requirement of A$8.9 million being met in the 2020 financial year.

The Primepower purchase will see Babylon acquire net assets including stock and work in progress of A$3.1 million, and goodwill and plant and equipment valued at A$1.1 million. As part of the deal, Primepower founder and owner, Michael Donegan, will also remain a Primepower executive for a minimum 12 months.

First Reserve becomes new owner of Weir’s Flow Control division

The Weir Group says it has completed the sale of its Flow Control division to First Reserve for an enterprise value of £275 million ($343 million).

The deal, which was first announced on February 25, completed on June 28, the company confirmed.

The Flow Control division primarily provides highly engineered pumps, valves and other solutions used in power, industrial and downstream oil and gas applications, according to Weir.

Back in February, the company said the sale would effectively strengthen its mining and oil & gas ties: “Once this transaction completes, on a pro forma basis, more than 80% of Weir’s revenues will be from attractive aftermarket-intensive mining and upstream oil and gas markets.”

Weir Group CEO, Jon Stanton, said: “The sale of the Flow Control division marks an important step in successfully delivering our strategy. It means Weir is now a more focused business with strong positions in premium upstream mining and oil and gas markets around the world.”

The £275 million enterprise value price is subject to customary working capital and debt-like adjustments, Weir clarified.

ABEL receives diaphragm pump order from Mexico miner

ABEL GmbH says it has received a large order for the delivery of 14 hydraulic diaphragm pumps from a Mexico mining company.

The Germany-based company received the order in March, with the pumps to be used for the transport of sulphuric acid-containing jarosite sludge in the course of zinc production.

ABEL explained: “The entire process of hydrometallurgical zinc extraction is also known as jarosite leaching. This process separates iron and zinc by chemical precipitation. This is the most used process of zinc production worldwide.”

Marthinusen & Coutts expertise keeps Africa mine pumping

Marthinusen & Coutts has come to the rescue of one of Africa’s wettest mines by rehabilitating medium voltage pump motors at the operation.

M&C’s Cleveland Engineering Services Division, a division of ACTOM (Pty) Ltd, recently teamed up with the Marthinusen & Coutts Kitwe facility, in Zambia, to carry out the work.

A pump original equipment manufacturer had approached M&C 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,” M&C, which calls itself the largest after-market service provider of electrical and mechanical rotating machines in Africa, said.

“Investigations revealed the motors driving the pumps were in a poor condition, with this severely affecting the availability and the performance of the pump chambers,” the company said. This required the initiation of a detailed refurbishment program, which involved 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, according to M&C.

“Where possible, the motors were repaired in-situ – thus avoiding any possible crisis of underground flooding – while others were removed for full refurbishment,” the company said. “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, according to the company.

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