High Angle Conveying, the Vital (missing) Link to IPCC Systems – 2017

Belt Conveyor Technology

High Angle Conveying, the Vital (missing) Link to IPCC Systems – 2017

Installations and recent studies have demonstrated the technical and economical advantages of high angle conveying for optimization of any IPCC system, yet that industry continues to struggle with the use of conventional solutions to achieve the high angle function.
(ed. WoMaMarcel - 07/4/2017)
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In 1980, at the end of the High Angle Conveyor Study, the USA Bureau of Mines funding was dramatically cut and the Bureau was reorganized and reduced to collecting data and publishing trends. BOM-funded studies of this type came to an end. It was left to Dravo Corporation to carry on the work to commercialization with its own funds. Subject to the same USA economic conditions, after a modest effort of short duration, Dravo management chose not to pursue the technology any further.

Continental Conveyor, on the other hand, had been recently purchased by the BF Goodrich Company, a large, well-funded USA company with a mission to become a major player in the mining industry. They determined that a successful high angle conveyor development would give them an advantage. The writer was approached by Continental Conveyor and offered “a chance to put my foot in my mouth”. He accepted the offer and joined Continental Conveyor in May of 1982.

With the most important research and development work already done, the Continental Conveyor management was anxious to build a full scale prototype of the Snake Sandwich high angle conveyor and, after a satisfactory testing period, move forward to the commercialization phase. There was an obstacle to this. The Snake Sandwich conveyor, the preferred system, was patent pending at the USA patent office. Though J.A. Dos Santos was the inventor, by the standard USA employment agreement, Dravo Corporation owned the rights to the pending patent. After further consideration and the realization that the obstacle could not be removed, Continental decided to pass up the preferred system. Development of the Mechanically Pressed Sandwich conveyor proceeded instead.

The decision to proceed was made in August of 1982. By July of 1983, the large scale prototype and demonstration system was ready to begin operation. Success was immediate. On day one, the system ran with Alabama Coal at 30°. The following day the high angle conveyor was first raised to 45° incline and later to a 60° incline. The coal was conveyed successfully in all cases.

In 1983, the HAC patent application, with J.A. Dos Santos as the inventor, was submitted to the USA patent office and to selected foreign patent offices. The patent was awarded in all cases.

From there, a year-long testing program revealed the characteristics and limits of the system. The results exceeded our expectations. We did not originally envision running this system above 60°. Extrapolating the test results clearly showed the system would be successful all the way to 90°. Indeed, some years later, the first commercial installation at 90° incline went into successful operation and many more followed.

The first commercial sale came in 1983 after that client observed their material, coal, running in the prototype system at up to 2000 t/h. Delivered to Triton Coal Company’s Buckskin Mine, Gillette, Wyoming, USA, the HAC began operation in 1984 delivering coal to train loading silos.

The second commercial sale was a significant leap and the first true IPCC application. The 2000 mm belt width system was designed to elevate 250 mm minus primary crushed ore at 4000 t/h from within the pit to the surface. At 93.5 m of lift, the conveyor drives were 3 × 450 = 1350 kW. The system operated successfully, at Maj-danpek mine, from 1991 until the mine shut down in 2002. Ref. [3] describes the project at the time of installation while Ref. [4] documents the performance after five years of operation.

Many HACs were designed and supplied by the writer. By 1997, at the time of my departure from Continental Conveyor, the count of HAC units reached 82.

At the 1997 founding of Dos Santos International, the writer returned to the preferred system at last, commercializing the Snake Sandwich conveyor. DSI Snakes are now in wide use throughout the world. Fig. 13 shows the highest volumetric rate Dos Santos Sandwich Belt high angle conveyor to date. Utilizing the widest belts to date, 2438 mm (96 in) running at 4.32 m/s, the system is designed to deliver 4536 m3/h (3629 t/h) of coal along a 50° incline from a Continuous Barge Unloader (CBU) up to the yard belts that deliver the coal to storage. This system, to operate over the Mississippi River in the USA, dramatically reduces the physical and environmental footprint when compared to the traditional switch-back conveyor arrangement that was first considered.


Fig. 13: The DSI Sandwich Belt high angle conveyor provides the most direct path, least physical and environmental footprint.

By 2002, the Continental HAC patents expired and DSI began offering their improved mechanically pressed sandwich belt high angle conveyor system dubbed the DSI GPS (Gently Pressed Sandwich).

Despite the undeniable success, Dos Santos Sandwich Belt high angle conveyors did not find additional applications in IPCC (In-Pit Crushing and Conveying) systems.

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