Modern Mining May 2016

MODULAR PLANTS

does not constitute a ceiling as we can imple- ment modules in parallel – in fact, we’ve quoted on plants as high as 1 000 t/h, consisting of 4 x 250/t modules,” says Westcott. “As a rule of thumb, I would say that modularisation works best for throughputs of up to 800 t/h. If you go much beyond this, the materials handling arrangements – notably the conveyor systems – tend to become too complex and start to negate the benefits of modularisation.” DRA’s modules are designed to process coal, iron, diamonds, chrome, manganese and min- eral sands, as well as metalliferous ores (both precious and base metals) that are disposed to pre-concentration and the removal of gangue using DMS and gravity separation technologies. Unit processes that can be addressed include crushing and screening, dense medium and spirals separation, filtering and thickening, along with materials handling and storage. The company is particularly strong in coal and its modules can be integrated for various coal wash strategies including production of ‘Eskom’ product, primary/secondary wash, production of sized products, as well as phas- ing or production build up. DRA has also done well with modular diamond plants, supplying everything from small exploration and bulk sampling plants at one end of the spectrum through to 240 t/h facilities using single and twin-streamed DMS modules. These plants have included modular recovery sections, as well as scrubbers, multi-stage crushing circuits, thickeners and flocculation plants. In respect of base metals, an effective appli- cation is the installation of modular DMS technology to reduce ore cut-off grades and upgrade mill feed, in the process reducing reagent consumption and electrical power requirements. A number of copper, zinc and nickel mines have benefitted from this approach. The suitability of an ore to this method of upgrade is dependent on the results of densimetric testwork. Although a library of pre-engineered stan- dard module and standard designs is available, DRA can also undertake the engineering and design of tailored modules. “We don’t have a ‘one size fits all’ approach – we accept that cli- ents might have special requirements and we are more than happy to accommodate these,” says Westcott. He also points out that DRA has partnerships with key equipment vendors when it comes to componentry such as screens, magnetic separa- tors, pumps, crushers, cyclones, thickeners and water tanks. “At the end of the day, the plant we supply will have DRA’s name on it – which

Coal modules can be integrated for various coal wash strategies includ- ing production of ‘Eskom’ product, primary/secondary wash, production of sized products, as well as phasing or production build up.

is an assurance of quality and reliability,” he states. “This in turn means that we have to ensure that all componentry meets the highest standards and is fully backed with excellent spares and service support; we only source from reputable companies who are leaders in their field.” Geographically, DRA has supplied its mod- ular plants throughout Africa and around the globe. Says Westcott: “We’ve sent our plants to Australia (where we have a 50 t/h chrome plant working), Canada, South America and Russia. In fact, Russia has been a great market for us and we’ve supplied 12 plants over the past 11 years, all of them to diamond producer Alrosa. Our latest contract – which we’re just finishing off – is for four modules, two of 65 t/h capacity and two of 110 t/h, in Siberia. The site is extremely remote and to get there from South Africa takes three days of flying – but we pride ourselves

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May 2016  MODERN MINING  41