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-6- <br />release, and rocks and mulch do not qualify as vegetative cover pursuant to <br />this rule. These standards enable the Division to determine: 1) If the <br />revegetation plan has been followed; 2) If the existing cover is sufficient <br />to provide effective soil stabilization; and, 3) If progress is being made <br />toward the ultimate goal of providing a permanent, diverse, and effective <br />vegetative community. <br />The Division finds that because Sun Coal Company has not submitted technical <br />data with reference to successful establishment of revegetation (based on the <br />cover standards of Rule 4.15.8) and has not documented revegetation <br />methodology, it has not satisfied a minimum requirement for Phase II Bond <br />Release. In addition, field inspections have noted the existence of <br />substantial gullying on the backfilled area, indicating that an effective <br />stand of vegetation has not been reestablished. <br />Sus ended Solids Determination - The Division required Sun Coal Company to <br />submit tec m ca ata w rc emonstrates that levels of suspended solids <br />contributed to streamflow or runoff outside the permit area are comparable to <br />the pre-mining condition. <br />During the period of this review, the Division has been examining the policy <br />for the Phase II bond release suspended solids determination. The policy, <br />which is nearly completed, will allow the operator to compare suspended solids <br />measurements from sediment control structure outlets to undisturbed or <br />pre-mine data in order to meet the requirements of Phase II. Pond inflow data <br />or direct slope erosion measurements would be required only for pond removal, <br />but could also be used to meet Phase II requirements. <br />Without the benefit of this policy, Sun Coal Company has submitted <br />calculations using the Modified Universal Soil Loss Equation (MUSLE) to <br />demonstrate that the sediment yield on the backfilled area meets the Phase II <br />criteria. This type of demonstration would meet the more stringent <br />requirements for pond removal. The applicability of this equation on <br />reclaimed lands in the Western United States is somewhat questionable, and is <br />the subject of continuing scientific research. For this reason the equation <br />must be used conservatively and reviewed carefully. <br />After completing its review of the submittal, the Division rejects the <br />demonstration for the following reasons: <br />1. The soil erodability factor (K) is the same for disturbed and <br />undisturbed land. Division calculations using the soil erodability <br />nomograph, and soil compaction data supplied in the permit <br />application, indicate that this factor should differ between the <br />pre-mine versus post-mine conditions. <br />2. Calculations by the Division indicate that rainfall and runoff factor <br />(R) were underestimated by the operator. This appears to be due to <br />omitting the snowmelt runoff factor. <br />