Section 434.80 - Specialized definitions(a) The term brushing and grubbing area means the area where woody plant materials that would interfere with soil salvage operations have been removed or incorporated into the soil that is being salvaged.(b) The term regraded area means the surface area of a coal mine that has been returned to required contour.(c) The term sediment means undissolved organic and inorganic material transported or deposited by water.(d) The term sediment yield means the sum of the soil losses from a surface minus deposition in macro-topographic depressions, at the toe of the hillslope, along field boundaries, or in terraces and channels sculpted into the hillslope.(e) The term topsoil stockpiling area means the area outside the mined-out area where topsoil is temporarily stored for use in reclamation, including containment berms.(f) The term western coal mining operation means a surface or underground coal mining operation located in the interior western United States, west of the 100th meridian west longitude, in an arid or semiarid environment with an average annual precipitation of 26.0 inches or less.