40 years gravel works Schraud – and a classifying plant made by SBM

To mark the special anniversary, Managing Directors Peter and Axel Schraud gave a future-oriented present to themselves: the start-up of a new high-performance classifying, conveying and loading plant made by SBM Mineral Processing in the 250,000 m² big quarry in the north of Würzburg, Germany.

Focus on Product Quality
Interface of the new classifying plant made by SBM is the secondary crushing stage of the existing plant system. The new 60 m long, 7 m wide and 27 m high plantclassifies crushed limestone with a feed size of 0-120 mm into nine individual fractions. An extra box for special products which can be filled by articulated lorries renders this plant even more flexible. Naturally, product quality came first at Schraud. Therefore, a dust reducing concept was devised with the company FB Filterbau right at the beginning. The high-performance plant provides filler-reduced crushed sand gained due to installing classifier pipes in the 0/2 screening funnel. The low fines content of the fractions is also due to the optimum dust reducing concept.

Three Screening Plants
“To obtain the requested end products a 2.5-deck, a 3-deck and a 2-deck expansion shaft screening plant with screen box dimensions of approx. 2 x 6 m were installed,” explains Regional Sales SBM Martin Schwab. ”In the generously dimensioned underground each concrete box is provided with the required dosing equipment to supply the loading conveyor with a capacity of 800 tons per hour with mixed aggregates or individual grain size fractions”.

At the beginning of the planning phase there was the question of choosing silos or concrete boxes for storage. Comparing the costs for the requested storage volume of 350 m³ per fraction clearly favoured the concrete solution. An additional strong point for concrete boxes is the fact that wheel loaders can drive on each box meaning that individual grain size fractions can be loaded by wheel loader. This considerably reduces the idle times of the lorries during sales peaks – which is already highly appreciated by forwarders and drivers.

Co-operation along the line
The key components of the conveying, classifying and loading plant were designed and manufactured at SBM. Co-operations with external partners were established for dust reduction, electric/control system and concrete construction. “Thanks to this clear distinction between constructions planning and assembly, construction and set-up took place without any problems between all parties concerned,” Mr Schwab emphasises stressing again the good co-operation with all partners.