Dr Peter Robinson

A wedged plane-flow hopper and horizontal belt feeder is employed to investigate the flow patterns and stress field redistribution at the hopper and feeder interface. The flow patterns are recorded by a high speed camera in conjunction with coloured material layers. The three-dimensional stress field in the feed zone and its influence on the feeder operation are discussed. The vertical stresses acting on the feeder for initial filling and flow conditions are measured along with longitudinal shear feeder loads. The experimental results are compared with theoretical values derived using relevant feeder load theories. The influences of different filling heights and clearance between the hopper bottom and feeder surface on feeder loads are presented. Numerical simulations using the Discrete Element Method (DEM) are carried out additionally to analyse feeder loads at the hopper and feeder interface, with the results being compared with those obtained experimentally.

The throughput of a belt conveyor system is the primary design parameter when considering a new installation, determined by the cross-section of the material on the belt, coupled with the belt speed. Optimizing this area not only improves efficiency, but also minimizes capital costs through the optimal selection of equipment. Whilst speed-related optimization has seen considerable attention, the cross-sectional area has largely been neglected due to existing design constraints of the system. Conventional belt conveyors typically utilize a 3-idler troughing configuration, which forms a trapezoidal cross-section with a parabolic surcharge. The rigidity of this support directly limits the geometry of the cross-section that may be considered. A new conveyor system developed at the University of Newcastle supports the conveyor belt by a rail-based carriage, with no relative movement between the belt and carriage. This configuration allows the cross-section of the belt to be freely optimized in order to maximize the material throughput for a given belt width, or alternatively to minimize the belt width for a given throughput. This article utilizes the calculus of variations to optimize the form of this cross section, and demonstrates that an increase in throughput of up to 30% is possible, compared to troughed installations.

Investigation and uptake of filtered tailings continues to grow throughout the globe. This is driven by a wide range of site-specific considerations, which include such factors as tailings characteristics (e.g., amenability to filtration), production rates, climate, water availability, cost drivers, environmental requirements, and social factors. Despite the aforementioned technological growth, the currently available filtration technology is not able to meet the needs of many operations and projects that would otherwise adopt the technology. Experience with large-scale industrial filtration shows that vacuum belt filter systems meet the needs of many modern users, exceptions being the inability to effectively dewater tailings at altitude and/or with a fine particle size distribution: a potential fatal flaw. This paper presents a case study on the utilization of the patented Viper Filtration technology on gold tailings to overcome this challenge and shares the resultant full-scale plant design, highlighting the features designed to overcome cost and scalability deterrents. This technology is a novel mechanical process which complements the vacuum pressure in dewatering the filter cake as it travels along the belt filter. This project commenced with a pilot testing program, which successfully met the objective to rigorously test, measure and record any performance improvements achieved when engaging the Viper technology. Of the two tailings products tested, gross improvements of 4.2%w/w and 5.7%w/w were achieved when compared to the conventional vacuum belt filter operation. This pilot testing facilitated measurement of operating and design data, which forms the basis of the full-scale system design and resultant equipment supply of three vibration roller assemblies for retro-fitting on the existing vacuum belt filter.

The energy loss due to indentation rolling resistance in a conveyor belt system can account for up to 60% of the total power usage. It arises due to an asymmetric pressure distribution as a viscoelastic belt cover is indented by a rigid idler roll. This causes a retarding moment on the idler roll, dependent on the load, speed, idler diameter and the properties of the conveyor belt cover. As pouch conveyor systems become more prevalent in industry, the supporting structure, and thus the indentation rolling resistance of such systems is of importance. These designs typically employ curved belt profiles, or spherical idlers in order to aid belt tracking and closing. From this, a spherical indentation into a generalised Maxwell backing is modelled, and compared with experimental values. In addition to this, the strain dependency across the contact is investigated.