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CONTRACTORS <br />ENGINEERS <br />DEVELOPERS <br />MORRISON-KNUDSEN COMPANY, INC. <br />E%EC UiIVE OFFICE <br />MORRISON~KNU DSEN PEA2A <br />PO DO% ]8081 BOISE. IDAHO 93]29 / U 5 A <br />PHONE X208) 3865000 / iE LE% 368<39 <br />iii iuiiiiiiiiii iii <br />999 <br />,._~r; .,wi s <br />September 11, 1986 <br />OCT ~ 1986 <br />.:.,. r. = .,., ~ <br />~yii~%i`u i_iii'Jl! F:t„_sZu:;y r ii.i~ s <br />rir. D.J. Rose <br />operations Manager <br />Yampa riining Company <br />P.O. Box HH <br />Hayden, Colorado 81639 <br />Dear rir. Rose: <br />Subject: Tipple Pond B Storage Capacity (Outfall 007) <br />I have reviewed the design calculations and as-built water shed survey <br />data for Pond "B" located at the Tipple Area of the Hayden Gulch Mine. I <br />am a registered Professional Engineer in the State of Colorado and am <br />experienced in the design and construction of water control structures. <br />The purpose of the review was to determine the effects, if any, of the <br />as-built water shed survey information on the design capacity of Tipple <br />Pond "B". Using the original design formula with the as-built data, <br />calculations indicate a 25-year, 24-hour storm event would result in 1.57 <br />acre feet of water in Pond "B". This combined with 0.16 acre feet of <br />sediment capacity yields 1.73 acre feet of storage capacity needed to <br />contain a 25-year, 24-hour storm event. A recent as-built survey of Pond <br />"8" indicates a maximum storage capacity of 2.17 acre feet. <br />It is in my opinion, based on the original design assumptions and as-built <br />data, that Tipple Pond "B" will contain the runoff from a 25-year, 24-hour <br />storm event with a 1 foot minimum freeboard and no discharge. With this <br />information and past construction certification, this pond should meet the <br />CMLRD requirements. <br />ol. ~o~~G15IE9f~ C~(/ <br />q ' <br />0 . b . <br />4/ ~~ tt ty _- <br />0'LauKhl - olorado RegiiFY~ea~~~ R~$*1i;342. <br />JOL/lab <br />2000h <br />