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`' ~ ~ ~. <br />P- 9 <br />Preliminary Adequacy Review - Grassy Creek Mine <br />April 28, 1981 <br />2.05.3 Operation Plan - Permit Area <br />1. Please state the anticipated total production of coal for the life <br />of the operation to comply with 2.05.3(1). <br />2. Because of past slope stability problems with cut slopes at this <br />particular mine, the applicant should supply adequate cross sections and <br />stability analyses of typical steep cut slopes. The applicant should <br />also include a discussion of construction specifications to be followed ~' <br />to assure stable cut and frll slopes. The cross section given on page <br />II-8 of the application is insufficient. <br />4. Please provide information in sufficient detail to determine the <br />effectiveness of the berm in spill prevention and sediment control for <br />the fuel storage area. Of particular concern is the effectiveness of <br />the berm in reducing the potential impact on essential hydrologic <br />functions of the local drainage and Grassy Creek. <br />5. The applicant must supply sufficient supporting information for <br />determining the required diameter of culverts to be used. This information <br />should include contributing drainage area, runoff estimates, typical <br />culvert installation and all assumption and calculations sufficient to <br />demonstrate compliance with 4.03.1(9)(e). <br />2.05.3(9) Ponds, Impoundments and Diversions <br />1. Section 2.05.3(9)(a) requires that a detailed design plan for all <br />sedimentation ponds be provided to meet all requirements of 2.05.3(9)(a) <br />(i) and (ii) and the performance standards in 9.05.6. This information <br />is necessary to demonstrate the capability of the structure to control <br />the amount of sediment released from the mine site. The detailed <br />design plan should also be accompanied by all supporting calculations <br />of volume of runoff and sediment. <br />2. Because of the nature of the bedrock and the use of the first cut <br />for sedimentation ponds, the applicant should provide a discussion (and <br />data) of bedrock orientation and water levels for design storms to aid <br />in determining the possible implications of the down slope stability of <br />the containment. <br />3. Detailed design plans and supporting calculations (contributing <br />drainage areas, cross sectional area, slope,velocity, etc.) must be <br />submitted in support of the sizing of all ditches. This information as <br />required to determine compliance with 2.05.3(9), 9.05.3 and 4.05.9. <br />