How the Right Filtration Solution Is Helping to Keep SA’s Power On

Responsible for supplying Eskom’s Medupi Power Station with around 14.6 Mt of power station-grade coal annually for the next forty years, Exxaro’s Grootgeluk Coal Mine is playing a crucial role in keeping the power on in South Africa.

Doing so demands an uninterrupted supply of clean process water at the mine’s coal beneficiation plants, and Superior Filtration’s Kleerflo self-cleaning filters have proven to be the superior home-grown filtration solution for minimal maintenance, virtually no downtime and increased output, even in the toughest coal mining operations.

Situated within the Waterberg Coalfield in the Limpopo province of South Africa and just 25 kilometres from Lephalale, the Grootegeluk Coal Mine is an open cast coal mine that employs 2,000 people and is operated by Exxaro, South Africa’s largest and foremost black-empowered coal and heavy mineral company.

Exxaro was awarded the contract to supply Eskom’s Medupi Power Station with coal and invested R9 billion to speed up extraction from the existing pit to meet the expected demand from Medupi, the fourth largest coal-fired plant and the largest dry-cooled power station in the world. This green-fields coal-fired power plant comprises of six units rated in total at 4 800MW installed capacity.
Two new dense media coal beneficiation plants were built at the mine which, at full capacity, will supply the Medupi generators with about 14.6 Mt of power station-grade coal annually for the next four decades.

To achieve this – and thereby contributing significantly to keeping the power on in South Africa – the mine beneficiation plants require an uninterrupted supply of clean process water. This is particularly crucial for the operation of the Reflux Classifiers for fines beneficiation, which are relatively new and were installed as part of the new plant at Grootgeluk to enable the recovery of valuable material during processing.

Reflux Classifiers are designed specifically to upgrade fine minerals generally finer than 2mm, and the slurry-based gravity separator technology consists of a system of parallel inclined channels and a fluidised bed with fluidisation nozzles. Blocked fluidisation nozzles are a widespread problem in fluidised bed systems in which fine or tacky products are processed.

Operating these systems without the correct filtration solution required daily process interruptions at the mine to allow time for cleaning blocked fluidisation nozzles, which proved to be both expensive and resource intensive.

Looking for a solution that would reduce maintenance and downtime, while increasing output, the Exxaro inhouse design consultants reached out to Superior Filtration, which has over 38 years of experience in water filtration with a strong emphasis on mining applications.

The Superior Filtration engineers were able to provide valuable technical input based on their extensive experience at other Reflux Classifier installations, including the Moatize Coal Mine in Mozambique, where Kleerflo filters are successfully installed on fluidization nozzle feed water for FL Schmidth Reflux Classifiers, as well as at mining operations in Australia.
The Superior Filtration team also provided a trial Kleeflo filter unit for a test run, to enable the Exxaro team to verify the claim that Kleerflo filters are the best filters to use for protection of nozzles in fluidised bed separation processes.

Created specifically for tough industrial applications, the design of Superior Filtration Kleerflo Filters are underpinned by inherent simplicity, which means the filters have no electric motor, no close tolerance elements, no rotating parts, and very few moving parts, while featuring high quality, durable, stainless steel wedgewire screens that eliminate the need for manual pre-screens and never have to be replaced.

Experiencing first-hand that these features translate into efficient filtration and filtrate within standards that virtually eliminates nozzle blockage, while offering the long uninterrupted filter runs and completely autonomous function including backwash, the Exxaro team was convinced that they had found the right filtration solution.

The mine was satisfied that KPI’s set out at the commencement of the trial had been satisfied, that the success criteria had been fulfilled and that the Keerflo self-cleaning filters had proved to effectively remove oversize particles from nozzle feed water, with virtually no downtime, zero electrical energy consumption, the lowest maintenance costs, and the lowest lifetime cost.

Superior Filtration remains in regular contact with the mine, offering diagnostic and support service via telephone or WhatApp, as it does for all its clients. As the mine requires new filters on similar applications, Kleerflo filters remain the top choice.

The results achieved at Exxaro’s Grootgeluk Coal Mine provides further evidence that choosing the right filtration solution – one that works for decades with no hassles in the toughest environments, while also delivering additional benefits – is a critical decision best made with assistance of specialists with a proven track record, who are fortunately just a friendly call away.

The Superior Filtration diagnostic team invites both design engineers and end users of filtration systems to make contact via telephone or WhatApp and to benefit from our no obligation diagnostic service, technical input and the provision of a trial unit to demonstrate the superior results that are achieved when the right filtration system is correctly specified by specialists in the field to fulfil all the necessary requirements.

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