Laserfiche WebLink
Revised Storage Capacity Certification <br />I am a registered professional engineer in the State of Colorado experienced <br />in the design, construction and operation of earthen structures. I have <br />reviewed the as-built documents and inspected the site. Exhibit 13-4A, As- <br />Built Pond 010, presents the existing configuration of the impoundment. To <br />the best of my knowledge, based on my professional expertise, and to the <br />extent possible, Pond 010 was constructed in accordance with prudent state- <br />of-the-art of earthen embankment structures. Further, the structure was <br />constructed in compliance with the approved design, to the extent possible, <br />as specified in Attachment 13-3 of the approved mine permit application. <br />Minor field adjustments in horizontal and vertical alignment were necessary <br />during construction to compensate for unanticipated natural conditions, limit <br />the disturbed area, and construct a structure consistent with the existing <br />and reclaimed topography. The upstream and downstream slopes were flatted <br />and the overall width of the dam increased. This was done based on the wet <br />conditions encountered when the topsoil was removed from the dam location and <br />ponding area. The toe drain was also changed to a stronger schedule 3039 <br />perforated pipe instead of just slotted PVC. <br />This as-built report confirms the construction of this structure meets or <br />exceeds the Rules and Regulations of the Colorado Mined Land Reclamation <br />Board for Coal Mining. Seneca will inspect the pond quarterly to evaluate <br />structural integrity, storage capacity conditions, and remedial work <br />requirements in accordance with the approved mine permit application. <br />Therefore, pursuant to Rule 9.05.9, the above is the Sedimentation Pond 10 <br />as-built certification report. <br />~~ ~~~~\\ I I I I I I I I I I I I I/// r r rr/ <br />~~```~\\\p00• REG~ ///~~%i <br />OO,O•p,.•HfTT~•. ~~G <br />-~ • ° 18406~A • ~/ <br />~~/rrriril~~1~1~I~I~IJ1J1\\\~~~"`~\ <br />David A. Hettinger <br />Colorado P.E. 18906 <br />~~~ v~~ 7 <br />Date <br /> <br /> <br />`J <br />TR-35 13-3A.6 Revised 09/07 <br />