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b. There appears to be a discrepancy in total number of sediment ponds <br /> at Coal Basin. Chapter IV, page 19 indicates the presence of <br /> 30 ponds, the Permit Renewal Findings Document indicates 36 ponds. <br /> and a count from the various maps in the application shows <br /> 34 ponds. This discrepancy needs to be resolved. <br /> c. Demonstrations for small -area exemptions for four previously <br /> identified areas which do not drain into a sediment pond are <br /> necessary. Appropriate alternative sediment control measures will <br /> need to be proposed. demonstrations will need to be made that the <br /> alternative measures will achieve compliance with Rule 4.05.2(3), <br /> and the measures will need to be implemented as required. <br /> Acceptable approaches could include construction of total <br /> containment berms or a showing based on appropriate modeling that, <br /> due to vegetation cover. gravel surfacing, or other factors, runoff <br /> resulting from a 10-year, 24-hour event would not exceed applicable <br /> effluent limitations. <br /> d. The "storage area" southwest of the No. 1 Mine is apparently outside <br /> the sediment control system, but evidently has been used for various <br /> purposes by Mid-Continent Resources subsequent to passage of the <br /> Surface Mining Control and Reclamation Act. The operator must <br /> either demonstrate that the area qualifies for alternative sediment <br /> control (as a small-area exemption), or must design and construct <br /> sediment control facilities in accordance with Rules 2.05.3(4) and <br /> 4.05. It is not clear to us whether this area is also the No. 1 <br /> Mine landfill discussed in Chapter II. page 44, and approved in a <br /> Technical Revision dated October, 1985. If not, Mid-Continent will <br /> need to provide an updated map of the No. 1 Mine area showing the <br /> location of the landfill . <br /> 5. The Division has identified a number of issues concerning the reclamation <br /> and revegetation plans at Coal Basin. These are as follows: <br /> a. Some refinement of the topsoil replacement plan would appear to be <br /> warranted. Volume of topsoil in various stockpiles will need to be <br /> quantified, topsoil "borrow" areas need to be identified and <br /> available topsoil volumes estimated. Based on available volumes, <br /> and considering the required replacement depth for the Sutey refuse <br /> pile, a detailed replacement plan for remaining disturbed areas will <br /> need to be provided. This information will need to be submitted by <br /> September 1 , 1991 . <br /> b. Three reference areas were established during baseline data <br /> collection in 1979-80, and were demonstrated to be similar to the <br /> plant communities to be disturbed. Success standards were also set <br /> based on baseline sampling on other areas of the same plant <br /> communities. Rule 4.15.7(2)(d) allows determination of revegetation <br /> success by comparison with established reference areas, but does not <br /> allow the setting of cover and productivity standards by the second <br /> method. <br /> -7- <br />