9.2.3.3 Divide the crushed sample by using a large riffle.
Riffles properly used will reduce sample variability but cannot
eliminate it. A typical enclosed riffle is shown in Fig. 2 and
described in 6.2.2. Pass the coal through the riffle from a feed
scoop, feed bucket, or riffle pan having a lip or opening the full
width of the riffle. When using any of the preceding containers
to feed the riffle, spread the coal evenly in the container, raise
the container, and hold it with its front edge resting on top of