Evolution of sandwich belt high-angle conveyors

CIM Bulletin, Vol. 76, No. 855, 1983

JOSEPH A. DOS SANTOS, Design Project Engineer, Dravo Corporation, EARL M. FRIZZELL, Mining Engineer, Spokane Research Center, U.S. Bureau of Mines

Conventional belt conveyors offer an economical method for transporting materials at inclines approaching 18 degrees. Sandwich belt conveyors may be used to transport materials at high angles, to 90 degrees, while maintaining the most positive features of conventional conveyors, that is, (1) proven conventional conveyor components, (2) high-speed operation, (3) high-single lifts, (4) continuous cleaning of the smooth surfaced belts, and (5) easy, quick repair by hot or cold vulcanizing. The present discussion deals with the evolution and development of sandwich belt conveyors to satisfy the operational requirements of the open-pit mining and materials-handling industries. A look at the limitations of conventional shallow angle conveyors reveals the conveying angle at which a cover belt is needed. The relationship between conveying angle and hugging pressure by the cover belt is developed mathematically. A study of past and current developments reveals that the Loop Belt and Beltavator are significant advances in the state-of-the-art. The vertical radius of curvature constraints are discussed in detail and the constraint equations are developed. Criteria for future development is established as a basis for evolutionary developments in sandwich belt high-angle conveyors. The use of intermediate drives in sandwich belt high-angle conveyors is investigated.
Keywords: Open-pit mining, Belt conveyors, Materials handling, Sandwich belt high-angle conveyors, Mechanically-pressed sandwich conveyor, Pneumatically-pressed sandwich conveyor, Air-slide sandwich conveyor, S-shape sandwich conveyor, Snake sandwich conveyor.