Tag Archives: hydrocyclone

Weir’s Cavex hydrocyclones boost yields, production at Yoctolux Collieries operation

Coal technology, Mine operation news, Mineral processing, Mining equipment, Mining services, , , , , ,

Yoctolux Collieries in Mpumalanga, South Africa, has achieved improved yields and production throughput with the installation of a Cavex® 500CVXT20 DM hydrocyclone from Weir Minerals Africa, the OEM says.

Part of the Tala Group, the open-pit coal mine was looking to improve the performance of its dense media separation (DMS) circuit in its Wash Plant 1. The existing 610 mm cyclone, installed during the mine’s initial design phase, had an operational life of only six months between refurbishments.

Members of the Weir Minerals Middelburg branch and hydrocyclone product team conducted a site audit, revealing the incumbent cyclone was operating inefficiently. A “wash-ability” analysis showed that an improved yield could be achieved using the Cavex hydrocyclone technology on the DMS circuit, Weir said, with the customer specifying that the product would have to offer improved separation efficiency, increase wear life and match the existing cyclone footprint.

Following a proposal that included dense media (DM) hydrocyclone simulations, a Cavex 500CVXT20 DM hydrocyclone was installed in August 2017. Manufactured from mild steel, it is lined with 25 mm slip-casted radius ceramic tiles manufactured with 92% alumina content.

To date, the hydrocyclone has achieved higher separation efficiency through an average 15% yield increase, according to Weir. It has achieved an overall average of 75% yield for both of the mine’s coal types – grains and peas. This compares favourably with the 65% achieved previously by the competitor’s cyclone, Weir said.

There has been a 49% throughput increase in production tonnage, from 78 t/h to 116 t/h as a result of the reduced turbulence in the hydrocyclone’s design. The mine has also seen significant wear life improvement, with the Cavex DM hydrocyclone requiring only a spigot replacement after nine months, according to the equipment manufacturer.

So satisfied was the management at Yoctolux Collieries that they placed an order for an additional Cavex 500CVXT20 DM hydrocyclone in May 2018. This replaced the competitor’s cyclone on Wash Plant 2, with the replacement based on the improved metallurgical and operational benefits obtained by the Cavex hydrocyclones.

Namakwa enlists FLSmidth pumps to cut downtime, costs at Kao diamond mine

Comminution of minerals, Diamond mining, Equipment maintenance, Mine operation news, Mineral processing, Mining equipment, Mining maintenance, Mining services, Water management, , , , , , , , , ,

The installation of a FLSmidth KREBS millMAX™ pump at Namawka Diamonds’ Kao mine, in Lesotho, is, according to the mining equipment maker, providing the miner with significant cost savings through increased impeller, casing and back liner wear life.

FLSmidth’s engagement at Kao started when the mine required a pump conversion in the field – an undertaking that can be difficult and time consuming, according to the mining OEM. “It is also a high-stakes operation as a cyclone feed is critical to the overall process and ability to generate returns. A wrong decision can mean a lot of lost revenue,” the company said.

It was the potential for cost efficiency that convinced Kao diamond mine to implement the KREBS millMAX Pump. After initial discussions, the first trial pump – a millMAX 8×6 centrifugal seal (C/S) – was installed in a cyclone feed application (DMS 2 pump 1).

Initial results after seven months showed the millMAX was performing extremely well on the wear side, according to FLSmidth.

“So, once you get the green light, you need to confirm the duty details and measure up the existing installation to ensure that when you begin to install the pump there are no surprises,” the company said.

Brad Moralee, Head of Product Unit Pumps, Cyclones and Valves at FLSmidth, said: “It’s high pressure for us: you are typically given a window of opportunity during a shutdown to complete the change, after which the new pump must run as expected when the plant is re-started.

“You need the combination of a great product but, more importantly, great technical understanding of the duty to be able to propose the correct solution. We understand what is at stake from the customer side.”

The change produced impressive results in comparison with the previous solution from another supplier, according to FLSmidth, with the millMAX increasing the wear life by nine times, across impeller, casing and back liner. “This has seen Kao make significant cost saving on direct replacement costs, reduced downtime and saved labour expenditure,” the company said.

While Kao mine operators were impressed with the benefits from the switch, a slight gland leakage was causing concern, according to FLSmidth. To resolve this, FLSmidth suggested running a one-month trial with the slurryMAX, which had just recently arrived on the South Africa market.

“The slurryMAX trial was based purely on its sealing capabilities as Kao were confident of the hydraulic performance of the pump and had no concern about wear as they were confident the slurryMAX would show predictable and even wear life across all wet-end parts,” the company said.

Kao’s confidence also came from the fact the slurryMAX design is based on the millMAX range, whose wear ring technology has created an efficient and long-lasting slurry pump.

The main difference between the millMAX and the slurryMAX is that the millMAX is an all-metal pump meaning it does not have an outer casing and an inner wear liner (the casing itself is made from the high chrome wear material), while the slurryMAX is a split casing design that has a replaceable inner liner. The purpose of this design is that multiple material liner options are available to fit in the same outer casing.

“The slurryMAX features an improved, more efficient impeller and an optional water drain plug for easier maintenance, allowing water that might have settled at the bottom of the pump to be drained quickly,” the company said.

Leigh Rieder, FLSmidth Sales Engineer, concluded: “Kao is extremely happy with the hydraulics and lack of excessive wear of our pumps, which has meant that their cost of ownership is low. We have recently received an order from the customer for two more slurryMAX pumps and they have expressed interest in our slurryMAX 6×4 and slurryMAX 10×8 pumps.”

Metso commits to a filtered tailings future

Bulk handling, Comminution of minerals, Environmental, Mineral processing, Mining equipment, Mining industry recognition, Mining services, Sustainable mining, Water management, , , , , , , , , , , , ,

Metso might have just launched a new tailings management concept, but the management of tailings and dewatering solutions are nothing new for the mineral processing company.

Helsinki-headquartered Metso developed its first VPA filter for mining in the 1980s – the maiden unit being delivered to the Greens Creek mine in Alaska (now owned by Hecla Mining) – and has since dispatched hundreds of units to mines across the globe.

In addition, Metso has a long history of designing and manufacturing tube presses and other complementary dewatering solutions; its current membrane-type filter press offers pressures up to 100 bar for particularly difficult dewatering applications, such as china clay, while its inclined plate settler (IPS) and dewatering spirals offer separation and thickening options for miners.

The VPX™ filter is the launch product that comes with this new tailings management concept, but there is much more to this focus than a lone invention.

As Niclas Hällevall, VP, Process Equipment for Metso, told IM: “It is no longer a matter of just finding the most technically-suitable equipment or solutions to do the job. It is about how to transform mining into a sustainable and long-term development.”

Metso is intent on “challenging the conventional” in this regard. This includes looking at its own approach to designing mineral processing equipment – ensuring all products use, recycle and recover water in a responsible manner – as well as the industry’s way of thinking. Instead of pursuing short-term fixes, such as implementing tailings monitoring solutions using sensors, the company thinks miners should prepare for a future where wet tailings dams are eradicated from mine sites. Dry stacking – or filtering – tailings is the end goal Metso is pursuing.

This unconventional mindset is also apparent in the design of Metso’s VPX filter. Instead of equipping the machine for high throughputs alone, Metso has built the filter to manage varied input materials and to offer pressures up to 25 bars (and perhaps even higher pressures).

Metso has eliminated the use of hydraulics on this new filter, instead using electromechanical screws to achieve the high-pressure closing that turns wet material into dried cakes with as low as 7% moisture content in some applications. This electromechanical switch could cut operating costs due to a reduction in maintenance requirements, according to the company. The modular design, meanwhile, allows the filter to be scaled to any size, plus fit it into a container for easy logistics.

An advanced control system (ACS) using self-learning functions provide customers with a solution to monitor the operation of the filter, while there are plans to equip the machine with artificial intelligence functionality to monitor the conditions of the input material and select the optimal dewatering route.

Also, the filter press offers a variable and very fast opening and closing time thanks to the robust rack and pinion system, thus providing the high-capacity dewatering large mines require.

Metso is ready with its “future-ready” solution – a pilot VPX filter is currently in Sala, Sweden, about to be taken on a roadshow. This unit has already been tested on a mine tailings application in Sweden, IM understands, with the company expecting many more trials over the next year.

As Lars Gustavsson, Business Manager, Beneficiation Solutions, explained, the company’s filter press trial plan includes taking small size samples in its laboratory before graduating to the full-scale pilot unit, which is equipped with the same ACS and sensors commercial units will have. “This gives customers all they need to build the business case,” he said.

The Metso tailings management concept goes further: Hällevall says the use of the Metso IPS and Metso MHC™ hydrocyclone, in circuit with a VPX filter, results in less use of chemicals and energy in the dewatering process, on top of water recoveries of up to 90% in some applications. This is achieved by controlling the feed and optimising the filtration process. “We simply separate the stream into fine and coarse streams by using Metso MHC hydrocyclones,” Hällevall says, explaining that the overflow – the fines stream – is directed to the Metso IPS thickener, with the coarse stream going direct to the filter.

With two separate streams, the company can decide the optimum way to filter and dewater the material, with the IPC, in particular, offering the most “superior setting of fines using minimum amounts of flocculants and energy”, Hällevall says.

This new concept has allowed Metso to become one of only a few mining OEMs talking up the use of pressure filters – and accompanying separation and thickening infrastructure – to reprocess legacy tailings dams. The ability to “turn waste into value” could enable mining companies to not only clean up these dams, decrease their footprint and improve their sustainability credentials with local and other stakeholders, it could also allow them to generate additional revenue from the recovery of valuable minerals and metals.

This could potentially provide the positive investment case miners need to start making wet tailings dams a thing of the past.

Just 5% of all fresh tailings generated in 2018 were dewatered in some way, according to Metso’s data. With its own “future-ready” solution now in place, the company is doing its bit for industry to ensure this figure continues to rise.