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-2- <br /> 2. Designs for pond 3-1 , 3-2A and 3-2B indicate that a gate is used for the <br /> 6" CMP spillway. The applicant should indicate the use of this gate and <br /> indicate whether the gate is left open, closed, or partially open. With this <br /> information, the applicant should estimate the approximate detention time <br /> achieved in these ponds. <br /> 3. Page 59 of Volume 3 indicates that 0.5 cfs of mine effluent is to discharge <br /> to pond 3-1. Is this flow representative of the actual amount of water (range) <br /> being pumped to this pond and is the pond sized to accommodate this additional <br /> amount of water? <br /> 4. The two coal storage bins located below mine #3 are not contained within <br /> the sediment control system for this mine. The applicant should request an <br /> exemption from sediment control requirements in accordance with Section 4.05.2(3) <br /> and include a justification that would a1.1ow the Division to make a finding <br /> of compliance under Section 4.05.2(3) (a) , (b) (i) , or (b) (ii) . <br /> A revised map should be submitted which outlines and labels the specific <br /> areas for which a small area exemption is being requested. The acreage of each <br /> exemption should also be specified. <br /> Mine No. 4 <br /> 1. Map 11-B-App.7-Att.1 concerning details of pond 4-1 indicates that the <br /> equation Q=0.9 \/H Was used to graph capacity curves for the 6" CMP gate <br /> outlet. Could the applicant show the parent equation from which the discharge <br /> equation was derived? What equation was used to compute discharge capacity <br /> curves for the 12" CMP? <br /> 2. The applicant should explain the purpose of the gates used on the 6" <br /> CMP spillways. <br /> 3. The coal storage bin and S.E. corner of the mine pad are not included within <br /> a sediment control system. The applicant should request a small area exemption <br /> from sediment control requirements in accordance with Section 4.05.3(2) and <br /> include a justification that would allow the Division to make a finding of <br /> compliance under Section 4.05.2(3) (a) , (b) (i) , or (b) (ii) . <br /> A revised map should be submitted which outlines and labels the specific <br /> areas for which a small area exemption is being requested. The acreage of each <br /> exemption requested should also be specified. <br /> Mine No. 5 <br /> 1. Map 11-B-App.7-Att.1 concerning details of pond 5-1 indicates that the <br /> equations Q = 1.9 11 and Q = 5.1 -vH were used to generate spillway discharge <br /> curves for 6" and 18" CMP conduits. Could the applicant show the parent <br /> equation from which the discharge equation was derived? <br /> 2. Designs on the diversion and collection ditches, as well as the two culverts <br /> used at the mine, should be provided by the applicant. The designs should <br /> indicate that velocities are acceptable and will not result in excessive scouring <br /> of the lining or outlet. Calculations should also be provided to show that the <br /> structures will pass the 10-year, 24-hour event with adequate freeboard. <br />