Multotec
This filter press is one of Multotec’s large production designs and is capable of treating 35 tonnes of coal per hours

The global energy landscape is undergoing radical change as the world looks for cleaner, more environment-friendly electricity generation sources. This, however, is unlikely to affect the coal sector for the next 30 or more years, particularly in developing countries like South Africa and India.

This will see Multotec continue its focus on developing new and innovative technologies for the sector aimed at improving/streamlining efficiencies and enhancing production performance says CEO Thomas Holtz.

AUTHOR: Laura Cornish, editor of Mining Review Africa

The emerging junior coal sector

Holtz is bullish about the coal industry on the back of stronger performance over the last six to eight months and the emergence of a thriving junior sector in South Africa which is relying heavily on the expertise of equipment and service providers to extract value from their coal resources – an area Multotec is looking to exploit with its extensive metallurgical expertise.

One of the company’s most recent successes in the field was the supply of its entire equipment portfolio; including pumps, spirals, cyclones, screen panels, centrifuges a filter press, to a new discard dump retreatment process plant in Mpumalanga.

“This article first appeared in Mining Review Africa Issue 3 2018. Read the full digital magazine here or subscribe here to receive a print copy.”

The plant will be operated using the BOOM (build, own, operate, maintain) business model. Fraser Alexander has been responsible for this project and has sourced most of the equipment in the process plant from Multotec.

The project comprises 2 x 300 tph modules dense media separation (DMS) coal washing plant which will wash discard dump coal at a rate of 3.96 Mtpa with the potential to increase to almost 8 Mtpa spanning its seven years of planned operation.

Construction of the plant commenced in January 2017 and was completed according to schedule just 10 months later in October 2017. “The plant is operating to specification and nameplate capacity and is considered a Multotec flagship project,” Holtz notes.

Coal experts

The coal sector has, and is forecast, to remain the largest revenue and profit generator for Multotec – thanks largely to its global benchmark standards and extensive suite of consumable products well suited to coal washing and processing, which include:

  • Screening media – injection moulded polyurethane and polywedge screen panels;
  • Process equipment – dense medium cyclones, spiral concentrators, sampling systems, magnetic separators, centrifuges and filter presses; and
  • Ceramic wear linings – this product is used in high-wear conditions together with Multotec dense medium cyclones, centrifuges and pulley lagging.

The company’s understanding of the coal industry’s arduous and robust process requirements has further cemented it as a leader in this field.

“And thanks to our highly skilled and qualified engineers, we are not only able to deliver solutions according to the sector’s needs, but are also able to provide an after-sales service offering that ensures our equipment continues to function optimally throughout its lifecycle, which has become essential in today’s market,” Holtz explains.

This has consequently seen Multotec’s Middleburg branch grow substantially over recent years.

Today it employs over 100 people who are now recognised for their maintenance and quick response service.

“It has become essential to be positioned in close proximity to our clients to provide them with the best service delivery and our Middleburg branch, situated in the heart of the South African coal fields, has proven the value clients place on this offering.”

Condition monitoring of cyclones has become an after-sales service area that has gained momentum more recently.

Multotec has enhanced its offering to suit this growing need and now uses a fish eye lens on a digital camera, which inserted into the cyclone, can provide a full 360° view of the cyclone’s interior.

This in turn enables the company to best determine the condition of the cyclone in order to anticipate failure and schedule repairs if necessary.

Research and development still a major focus

Continuous research, development and innovation is another principle differentiator within Multotec, driven largely through its customer interface at all levels which results in the provision of appropriate solutions.

“Our commitment to provide process solutions that offer the highest integrity and reliability is underpinned by extensive experience in all minerals processing sectors to help drive operating costs down and improve production performance and efficiency. Coal is an important research focus area and one where we are still looking to add significant value,” Holtz outlines.

Multotec is currently testing a new high capacity, low cut spiral which will offer a low density cut without compromising on high throughput capacities – which has become a more prominent challenge in coal process plants. The intention is to launch the new spiral before the end of 2018.

The MD also notes the revival of samplers in the coal sector – largely through Eskom which is putting more focus on verifying coal quality prior to use in power stations.

Because 40 – 50% of all South African thermal coal is transported to the respective power station via truck (and not conveyor), Multotec is working on a sampler prototype which can take a truly representative sample off the back of a truck before it is off-loaded.

“The success of this product will require the sampler to take a proper cross section of the material and this is what we are focusing on now that the mechanical components are in place. Sampling technology has become far more sophisticated, enabling us to work on introducing a new and innovative product to the market which we expect will be well received.”

Products and services aimed at improving the coal sector’s environmental footprint

Eliminating the need for slimes dams has become a major mining industry drive which is particularly prevalent in the ‘dirty’ coal sector.

Multotec has the local distribution rights to sell Ishigaki and Micronics filter presses – high-capacity, automated filtration systems that Holtz says offers low maintenance requirements high through put rates and optimal, consistent separation efficiency.

“Filter presses recover all process water and therefore eliminate the need for slimes dams and reduce potable overall water consumption on the plant. We anticipate more activity from this business line moving forward. We also offer full-scale service contracts for this machinery as it requires more regular maintenance to ensure the equipment is functioning optimally.”

The company’s injection moulded TeePee panels, first launched in 2012, has also ushered in significant improvements and cost savings in coal dewatering applications.

The TeePee panel was developed with open area in mind and the resultant design provides a significant open area that has been shown to be double what was previously achieved with conventional Multotec Hi- Flow panels for the same aperture and with double the drainage capability.

In dewatering applications there’s a 50% improvement in drainage, further reducing the moisture content of oversized material.

“This makes the panel an ideal solution on plants where existing dewatering screens are overloaded and has proven particularly successful in the coal sector,” Holtz notes.