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Adams County <br /> Arapahoe County <br /> Aurora,CO <br /> E-470 Public Highway Authority Brighton,CO <br /> 22470 E.6th Parkway,Suite 100 <br /> Commerce City,CO <br /> Aurora,CO 80018 <br /> E470. 303.537.3700 Phone Douglas County <br /> 303.537.3472 Fax 1/ l Parker,CO <br /> Public Highway Authority dM �//� Thornton,CO <br /> July 2, 2014 <br /> RECEIVED <br /> Tyler O'Donnell <br /> Department of Natural Resources JUL 0 7 2014 <br /> j Colorado Division of Reclamation,Mining& Safety Division of Reclamation, <br /> 1313 Sherman Street,Room 215 AMnin0&Safety <br /> Denver, CO 80203-2243 <br /> Re: Henderson Development,Permit No.M-1980-110(Sandy Acres Pit) <br /> 112 Permit Amendment Application <br /> Dear Mr. O'Donnell: <br /> Thanks for your May 28, 2014 letter regarding the above subject. I'll provide resp—�to your <br /> questions in the same order as your letter: <br /> 6.4.5 EXHIBIT E-Reclamation Plan <br /> 1) Rule 3.1.5(9): <br /> a. I enclose a signed affidavit certifying that the backfill material is clean and inert per <br /> Rule 1.1(20). <br /> b. Mining associated with permit stopped around the mid 1990's according to some old <br /> documents I have reviewed. At that time, it appears that the operator anticipated <br /> filling the lake and then building some commercial or residential development— see <br /> attached Exhibit E from the 1980 permit. Mining had already ceased by the time the <br /> Authority acquired the property in the late 1990's. In the early 2000's we changed the <br /> configuration of the local roads to accommodate construction of the E-470 highway <br /> and the property is now effectively land-locked. This means it is no longer viable for <br /> development. Consequently,the Authority intends to return the property to rangeland <br /> or pastureland by planting native seed after the lake has been filled. <br /> c. The material in the lake will be placed and compacted by front end loader wheel <br /> and/or dozer track to minimize any voids or settling of fill material. In place <br /> compaction or material density will not be measured. Instead, we will monitor the <br /> placement and approve a method that achieves the general performance goals of the <br /> operation and the intended ultimate proposed land-use as indicated above. We expect <br /> the material will be adequately compacted during the placement process. In addition, <br /> the contractor will provide a one-year warranty for the project. The construction <br /> contract will require filling to the prescribed finished grades shown on plan sheet 5 <br /> which was included in Exhibit F. In the event any material settles during that period, <br /> we will require the contractor to fill any significant low spots. This process should <br /> result in fill densities that are comparable to those in typical rangeland or pastureland <br /> environments. In conclusion, in our engineering judgment, the methods and <br /> procedures outlined above will result in an acceptable fill density for typical <br /> rangeland or pastureland. <br />