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1.SH:1.OV. Much of the inside of the pond is incised or dug from <br />original ground, therefore, the steeper slope on the inside is <br />acceptable. <br />7) Pond Depth Design: 15.0 ft. Measured: 15.9 ft. <br />8) Rip Rap Lining in Emergency Spillway Design: 12" thickness of <br />10" to 12" rip rap, durable rock. Measured: 12" thickness of 10" <br />to 12" rip rap, durable rock. <br />9) Sediment Storage Volume: Design: 0.22 acre-feet. Measured: 0.4 <br />acre-feet. <br />10) Storm Detention Volume: Design: 4.08 acre-feet. Measured: 4.1 <br />acre-feet ± 4~. <br />11) Rip rap at Discharge of Principal Spillway: Design 8" <br />diameter durable rock. Measured: as designed. <br />12) Compaction of Embankment: Since my first inspection occurred <br />before the final dam was constructed, I was able to determine the <br />effectiveness of the compaction within the dam itself. The weight <br />of the large hydraulic excavator on the dam during construction <br />was able to achieve proper compaction, in the order of 85~ to 90~ <br />of the maximum dry density. This was also verified in the final <br />inspection. <br />There was no evidence of cracking, bulging, sliding, seepage or <br />other construction problems. I certify that the sediment pond at <br />the Rimrock Mine has been constructed according to the plans <br />previously mentioned. Prudent state-of-the-art engineering has <br />been employed and the dam is sound, with no current environmental <br />threats or construction problems. <br />~POp AEO1S <br />o .•~O ~i• O <br />yl~. C~: <br />20336 ~ ~ <br />9o Sg/ONAtF'~ <br />DEC 2 91992 <br />MINERALS t6 Gtr . • , . . <br />