Riffle Sampler

For particulate materials, particle size often determines the sampling method. Larger particulate solids, such as ores, are sampled using a riffle, which is a trough containing an even number of compartments. Because adjoining compartments empty onto opposite sides of the riffle, dumping a gross sample into the riffle divides it in half. By repeatedly passing half of the separated material back through the riffle, a sample of any desired size may be collected.