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ATTACHMENT 2 <br />• <br /> <br />The following is provided in response to question no. 7 of the Division <br />letter of June 18, 1985. <br />Estimate of Flow to Sediment Pond <br />Disturbed Area Drainage 2.23 <br />Portal Discharge 0.09 <br />Coal Gulch Portal Discharge 0.09 <br />Total Capacity (Water) 2.41 Ac-Ft <br />Disturbed Area Drainage estimate from Appendix 1 <br />Drainage and Sediment Control Plan, April 15, 1985 2.23 Ac-Ft <br />Portal Discharge from Arness/McGriffin Portal <br />Estimated at 20 gpm <br />(20 gpm) (60 min/hr) (24 hr/day) 28,800 gallons/day <br />Use 24 hr detention time or contain 1 <br />day flow in sediment pond <br />28,000 7.41 gallon/ft3 43,560 ft3/Ac-Ft = 0.09 Ac-Ft <br />Portal Discharge from Coal Gulch Mine Assumed to be <br />Similar to Arness/McGriffin Portal <br />Use 0.09 Ac-Ft Additional Capacity <br />• <br />