The riffle splitter is a static and fractional sub-sampling device that can be used for dividing a lot of dry particulate material into two half-lots. The device is usually constructed with steel sheet and should be designed to have an even number of opposing inclined chutes (the riffles), with each chute having the same width. The recommended chute width should be at least 2.5× the size of the maximum particle diameter that can be found in the lot to be split. Riffle splitters are typically used in assay and analytical laboratories to reduce the size of samples provided from other sources (crushed rock, soils, powders and so on) to a lot size that is appropriate for the next stage of analytical sample preparation.
There are many different versions of the riffle splitter. However, not all can be considered correct sub-sampling devices, in that the two sub-sample halves are deemed to be representative of the original lot. The issue of correctness of a riffles split