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replacement. The major advantages of scarification are related to the physical <br />properties of the subsoil. The regraded spoil and respread topsoil is scarified to <br />decrease compaction, increase aeration and water movement, and increase plant <br />rooting depths. Increased water movement will also improve the rooting depths <br />of the planted species. <br />3. If none of the above procedures satisfactorily mitigate a certain problem, <br />DRMS will be notified and recommended actions will then be implemented. <br />WFC will maintain and periodically review the existing quality control program used to <br />evaluate weathered overburden, unweathered overburden, interburden, and subsoil <br />backfill handling activities at NHN Mine. These records will be kept on file at the mine <br />site and will be reported within the topsoil balance /subsoil quality report to be submitted <br />annually in the Annual Reclamation Report of each year. <br />NHN Mine, Spoil Compatibility and Erodibility <br />Determining the compaction potential of the backfill material is important to assess post - <br />mine subsoil conditions including: hydraulic conductivity, revegetation success, <br />landscape stability, and equipment traffic. Generally, stability and /or compaction <br />problems are related to soils high in shrink/swell clays, soils with large proportions of <br />sand and clay (sandy clay texture), and soils with approximately equal proportions of the <br />sand, silt, and clay -size particle fractions. These three conditions are not highly desirable <br />since a high shrink/swell clay content in post -mine landscapes causes poor stability and <br />low permeability conditions, a sandy clay textured soil develops surface crusting <br />problems, and an equal particle -size distribution may cause excessive compaction which <br />results in restricted water movement and root growth. <br />The first two considerations listed above were among those used for establishing the <br />suitability ranking system for texture. Unsuitable clay textures are identified in two thin <br />clay beds located in the uppermost overburden in the NHN permit area (see Section <br />2.04.6, Stratigraphy, Cross Sections A -A', Map 2.04.6 -4). These clay beds occur about <br />Section 2.05.4(2)(d) <br />Page 5 <br />January 2012 <br />