Modern Mining April 2021

come complete with all the complementary equip- ment. For example, the heavy mineral plant comes complete with desliming and dewatering cyclones, pumps and tanks, while concentrate and tailings stacker cyclones are optional. A four-stage spiral cir- cuit – Rougher, Cleaner, Re-Cleaner and Scavenger – is used and spirals are interchangeable depending on the mineral being treated. “The coal modular plant – designed to handle a 40 tph feed – comes complete with a sieve bend, desliming cyclones, pumps, tanks and spirals,” says Ramotsabi. Flexibility is a key attribute of these plants. Versatility allows for the flow sheet to be adapted to suit specific applications. The heavy mineral plant can be deployed across commodities, includ- ing chrome, copper, tin and mineral sands, among others. “The heavy mineral plant can also process both run of mine (ROM) material and tailing dumps. We have designed the plant to be flexible such that the spirals are interchangeable and can be utilised across a variety of minerals,” explains Ramotsabi. When in transit, the test unit’s stability is main- tained through support braces and dedicated lock-out switches for each pump. From a design perspective, the original plants had cat ladders, which were considered to pose safety hazards for operators. The new generation plants have been redesigned to include external walkways, making it safer for operators to do process control and access the different levels of the plant with ease. Meanwhile, Multotec, through its field service team, provides installation and commissioning assis- tance. Aftersales support is provided throughout the lifecycle of the plant by the company’s application engineers. The company also provides a consulta- tion service, while test work on spiral concentrators is conducted at Multotec’s R&D facility or at plant sites. Increased uptake Given the array of benefits offered by these modu- lar plants, Multotec reports an increased uptake in the market. To provide context, Ramotsabi says the company has in the past delivered 20 plants to a single customer processing alluvial chrome in dif- ferent regions of Zimbabwe. The company also recently delivered two heavy mineral modular plants in Zambia, where they have been deployed in a cop- per application. “We also have a large installed base of these plants in South Africa. We recently sold four units in the Burgersfort area, where we now have around seven plants in total operating in the area. We have three units in the Rustenburg area, and five in the Mpumalanga area. Generally there has been an increased uptake of these plants in recent years,” says Ramotsabi.

The biggest demand locally, says Ramotsabi, is in chrome applications. Responding to the indus- try’s need to re-treat chrome dumps, Multotec has in recent years adapted its versatile heavy mineral test plants to process ultra-fine chrome. “The majority of plants operating in South Africa are also in chrome applications. We have, however, also seen an increased number of enquiries from the mineral sands sector across southern Africa. Even locally in South Africa we have tendered on a number of projects in mineral sands,” concludes Ramotsabi. 

The Multotec modular spiral test units come preassembled making them easy to transport and erect.

Multotec offers modular spiral test units for heavy minerals and coal applications.

Key benefits of Multotec’s modular spiral test plants  The spiral test units are stand-alone units and can be skid mounted  Easily erected on site, with three primary modules  The flow sheet may be adapted to suit specific applications  ‘Plug and play’ capability  Units are easily moved and re-erected  Optional extras on the plant include samplers and process flow meters

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April 2021  MODERN MINING  31