The Mechanical Handling and Storing of Material

170 THE MECHANICAL HANDLING OF MATERIAL Concluding- Remarks.—Belt and scraper conveyors require less driving power than reciprocating trough conveyors (Rutschen). In other respects they are about equally as serviceable, but the latter are generally of a lower initial cost. Concerning the respective merits of Rutschen, those suspended on chains or links are more difficult, and therefore more costly, to move with the face; they depend on the timbering and their use is restricted to seams of certain limits. The type with independent trestle supports are more costly still in labour for moving, and also share the restrictions as to size of seam with those previously mentioned, but they have the advantage of being independent of the timbering of the mine. Those supported on rollers are the least expensive and simplest to move, are independent of the timbering, and are applicable to the smallest workable seams. From the above it appears likely that conveyors of the roller supported type will soon become as popular in this country as they are already on the Continent, where they are very largely used. The information contained in this chapter should be sufficient to build coal face conveyors of the Rutschen (Jog-trough) type in this country.