Barley

A stream size of anthracite known also as buckwheat No. 3, sized on a round punched plate. It passes through 1/4-in (6.4-mm) holes. At some mines, it has to pass over 3/32-in (2.4-mm) holes and at others over 1/16-in (1.6-mm) holes. The American Society of Mechanical Engineers has recommended that with a screen with circular holes, barley shall pass through 3/16-in (4.8-mm) holes and pass over 3/32-in holes. See also: anthracite coal sizes; bird's-eye. Fay

Source: Dictionary of Mining, Mineral, and Related Terms