Dramatic reduction in energy use and environmental impact can be achieved with sandwich belt high angle conveyors that serve as the vital link in any In-Pit Crushing and Conveying (IPCC) system. These high angle conveyors are not new at all, but have not found wide use in IPCC systems where they can realize the greatest advantage. IPCC systems were already realized in the 1970s. With the bulk material haulage limited to conventional open trough conveyors, the most direct path out of the open pit was not possible, requiring low angle spiral ramps and/or deep slots and/or tunnels through the high wall of the open pit. These excavations, to accommodate the low angle limitations, represented undesirable impact on cost and on the environment. Against this backdrop, a major study in 1979 sought to develop high angle conveying systems that could continuously haul the mined bulk material directly out of the pit, along the high wall—the shortest distance between the two end points. Between 1979 and 1982, that study developed sandwich belt high angle conveying systems that utilized all conventional conveyor equipment, including smooth surfaced rubber belts that could be continuously scraped clean. These systems had all of the positive features of conventional conveyors but overcame the angle limitation. By hugging the bulk material between two belts, the material’s internal friction could be developed to facilitate conveying at any high angle up to 90° (vertical). In 1984, the Majdanpek copper mine in Serbia, already using pit perimeter crushing and conveying, decided to move their primary crusher deep into the pit and to use a sandwich belt high angle conveying system to elevate the ore continuously, directly out of the pit, along the high wall to the pit perimeter where it then transferred to a conventional conveyor for the remaining haul to the plant. This significant sandwich belt high angle conveyor was only the second commercial sale. Many successful sandwich belt high angle conveyors followed with the current count of commercial installations at more than 200. Despite the great success in the Majdanpek system, its use has not been repeated as part of an IPCC system. The high angle conveyor offers the link to optimization of any IPCC system, yet that industry continues to struggle with the use of conventional conveyors and haul trucks to achieve the high angle function. The results are sluggish low angle conveyor systems of limited flexibility requiring excessive maneuvering time, excessive excavation and fill, re-handling and grading in order to accommodate the low angle limitations. Recent studies have represented resurgence in interest in high angle conveying and have demonstrated the technical and economic advantages along with the reduced environmental footprint. Though the primary purpose is to demonstrate suitability for open pit mining applications, this writing will first recap the early development of the latest sandwich belt high angle conveyors and their commercialization over the last 40 years. Particular emphasis will be on who did what, and when, giving due credit. This will show that since 1979, the constant of the development is the invention and the work of the writer. We will highlight the features that make Dos Santos Sandwich Belt high angle conveyors particularly energy efficient and suitable for use in the harsh requirements of the IPCC systems, highlighting the success in Serbia and in the latest studies. Finally, we introduce the latest structural support systems for long span, high lift high angle conveyors. These wire rope suspended systems, we call Flying Sandwich Belts.
