Processing Techniques

Processing techniques basically involve crushing and screening in crushed stone aggregates while sand and gravel materials are processed using screening and washing methods. These processes occur in an aggregate processing plant, whose objective is to prepare the materials in an adequate form for their final utilization as aggregates. Both types of aggregates finally need stockpiling and load out for transport. Upon sale, the final product is loaded on trucks, trains, or barges for transport to the market. Sand and gravel processing for most applications is first accomplished through washing to extract clayey components. Sand fraction separation, grading of the gravel into several, sand classification, and dewatering are the following processes until the final product is obtained. For crushed rock aggregates, after blasting in the quarry, trucks or conveyors move material to the processing plant where crushing (most operations use jaw and gyratory type crushers for primary crushing whereas secondary crushers are usually cone crushers or horizontal-shaft impact crushers) and screening are the main processes for producing fractions with the needed requirements. The processing methods require efficiency since the additional cost is added to the final product each time the aggregate is handled and/or processed.