Fig. 2. To-scale depiction of the sandwich cross-section with 350mm primary crushed rock. On the left is the section along a straight incline and on the right is the section along the transition curve

yet that industry continues to struggle with the use of conventional conveyors and haul trucks to achieve the high angle function. T e results are sluggish, low angle conveyor systems of limited fl exibility requiring excessive manoeuvring time, excessive excavation, fi ll and re-handling to accommodate the low angle limitations. T e current alternative to conveyors is the fall back position of using 300 ton haul trucks at great operating and environmental cost. Recent studies have represented resurgence in interest in high-angle conveying and have demonstrated the technical and economical advantages along with the reduced environmental footprint.

High angle conveyor to the resue in Australian project In 2008, a high capacity (8000 t/h) waste handling IPCC system at a Western Australian iron ore mine was limited in fl exibility and mobility by the conventional conveyors that linked the in-pit crushing system with the out-of-pit waste rock and overburden spreading system. Broad, low-angle ramps had to be built ahead of these conventional crawler-mounted conveyors. T e additional material handled and re- handled became cost and time prohibitive. T e entire system, more than US$100 million worth of equipment was ultimately abandoned, parked until a solution could be found. In 2011, Dos Santos International, through

its Australian partnership with Cortex Industries, was contracted to develop the high


angle solution, the vital link that would salvage the system. Fig. 1 depicts the solution. T e universal high-angle conveyor (UHAC), as dubbed by the customer, is a high capacity, mobile Dos Santos sandwich belt high-angle conveyor that can operate at various lift requirements, up to three benches (42m) and in both directions, elevating from the active pit to the spoiling surface and lowering to fi ll in mined out pits with the waste rock and overburden. Using 2,600mm wide belts this system can easily handle the 350mm primary crushed product at the mine production requirement of 8000 t/h, compatible with the in-pit crushing and spoiling system. Fig. 2 depicts to scale, the sandwich cross-section and demonstrates the principle that large belts can easily handle large lumps.

A lost opportunity? With the theory and basis fully developed by 1981 commercialisation began in 1983. Suitability for the rigours of IPCC applications was demonstrated in the 1990s by the second commercial sale, a signifi cant unit at a major Serbian copper mine. Yet despite the compelling advantages both technical and economic, the major IPCC system suppliers, consultants and mining companies continue to ignore the technology, foregoing the great potential for improved production and profi ts. ●

Joe Dos Santos is president of Dos Santos International

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