Modern Mining May 2015

CRUSHING, SCREENING AND MILLING

Careful screen media selection can reduce the ‘cost per tonne’ FLSmidth has a range of screen media and related products designed to increase throughput and product quality in the South African mining industry. “Lower commodity prices have meant that min- ing operations have had to increase their output in order to boost their bottom line or increase life and maintenance of engineered consumable products to reduce the ‘cost per tonne’ of the process. One of the ways of doing this is to look at screen media and their impact on production,” says David Sibley, General Manager: Screen Media, FLSmidth.

P roducts in the FLSmidth screen media range include woven wire screens, modular polyurethane and rubber screening panels, polyure- thane and rubber screening bolt down panels and tension mats, wedge wire products and wire conveyor belts. Screen media comprise a relatively small proportion of the total cost of a plant but play a critical role in productivity. It is therefore vitally important that mining operations not only ensure that they have the correct screen media in place but that the products used match the overall system. “FLSmidth has the necessary expertise to look at a total processing operation to see where improvements can be made. From the screen media side, we can look at any issues related to the process including wear, mass reduction as well as improvements in open-area percentage and machine opera- tion so as to increase the operational efficiency, throughput and lower the cost per tonne,” Sibley explains. “The open area, or the ratio of apertures to the total panel surface area, is of crucial impor- tance to screen users at a time when plants are upgrading their capacity to increase profitabil- ity and maximise screen performance,” Sibley continues. “FLSmidth’s modular panels are among the highest open area screen panels on the market at present. These combine all the advantages of reduced mass, high mechanical strength and longer wear life of polyurethane with a high open area percentage.” Modular panels are available in plain poly- urethane and rubber with additional hybrids listed as Poly Wedge, Poly Wire and Poly Perf. Looking at fastening systems, Sibley says FLSmidth has enjoyed great success with its patented Bolted Pin System (BPS), a modular polyurethane screening surface designed to meet the current and future needs of the screen

media industry. The grom- mets of the fastening system comprise a mushroom-shaped bush that is spigoted onto the top frame of the disc and securely L-bolted into posi- tion, thereby becoming an integral part of the frame. The pane l i s l a t ched securely to the frame, allowing for high g-forces during opera- tion of the machine. “This ‘bolted’ assembly negates the need for the over-size pins or sleeves whilst preventing the panel from ‘jumping’ out dur- ing normal operations which can be common with the tra- ditional pin systems,” Sibley says. FLSmidth has a range of

Ludowici reflux classifiers with nozzles.

Stringer cleats which are used with Meshcape™ polyurethane screen decks.

woven wire screening which it claims is the most versa- tile and common screening medium in the mining and aggregates industry. Sibley explains that there are two types of woven wire screen- ing available from FLSmidth. Woven wire screens are manu- factured from Vibro Optimax™ wire, AISI 304, 316, BMS and GMS, while woven wire mesh is commonly manufactured from AISI 304, 316 and BMS. “Our woven wire screens are manufactured from stainless steels, Vibro Optimax™ and other exotic materials. These round wires are woven into a weave pattern, with transverse wires holding the wires together to provide an excellent open area for peak performance,” Sibley says. The main benefit of this type of

Meshcape™ perforation plates.

feature

May 2015  MODERN MINING  57