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A limiting permissible velocity of 5.0 feet per second (fps) was used to ensure that the postmining <br />drainage channels would be nonerodible and stable. The permissible velocity was obtained, Table <br />3.4, from "Red Book" by Barfield et al., 1981 for a grass mixture vegetated channel. The shape <br />of the reclaimed channel was assumed for design purposes to be trapezoidal with 10h:1v side <br />slopes as a worst case condition. The side slopes will be no steeper than 1 Oh: 1v. <br />The channel bottom was calculated using the SEDCAD+ Version 3.0 computer program. The <br />channel width was increased to insure that the peak velocity was below the limiting velocity. The <br />typical trapezoidal channel section was selected for design purposes only for the entire length of <br />the reclaimed channel. "Reclaimed Drainage Channel Design" on the following pages contains the <br />specific design information of the reclaimed drainage channel in the eastern portion of the New <br />Horizon 2 permit area (San Miguel Draw). <br />The reclaimed drainage channels will be topsoiled and revegetated according to Sections <br />2.05.4(2)(d) and (e) respectively. Attachments 2.05.4(2)(C) -1 and 2.05.4(2)(C) -3, which <br />immediately follow this section, show the designs for these restored channels. <br />Any other channels which are left after reclamation are road ditches, as described in Section <br />2.05.3(3) - Mine Facilities. <br />Morgan Property Grading <br />At the request of the landowner, and in the interest in facilitating quality revegetation, the Morgan <br />Property grading plan has been revised (MR 89) to reduce grades and improve the consistency of <br />grades across said property. Map 2.05.4 -1 -3 shows the new post mine contours (ft. interval) over <br />top the pre mine topography. The chart below shows the overall improvement in grades on the <br />Morgan Property with this revision. <br />Morgan Property Grades <br />Pre -Mine <br />Topography <br />PR 08 <br />Topography <br />MR 89 <br />Topography <br />Average Land Slope <br />3.5% <br />3.2% <br />3.0% <br />Steepest Slope <br />15.6% <br />17.1% <br />14.7% <br />Revised March 2014 (MR 89) 2.05.4(2)(c) -9 <br />