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Mancos Shale is the stratum which underlies the deposit at the Anderson Pit. In order to prevent <br />exposing the shale to oxidation and potentially increasing selenium loading in the groundwater, <br />United Companies commits to mining no closer than 2' to underlying shale to include the <br />dewatering trenches around the perimeter of the pit. <br />United Companies mines using a O.SH:1 V to near vertical slope on active mining faces. <br />Highwall mining will progress to an offset of the crest line which marks the mid-slope of the <br />final mining 2H;1 V slope. Both boundaries will be staked prior to mining in the area. This <br />offset serves two purposes. First, the volume of material left in the highwall will allow the crest <br />to be pushed towards the toe with the final mining slope of 2H:1 V, which will maximize gravel <br />recovery and additionally will reduce the required backfill material to bring the slopes to a <br />3H:1 V slope. Secondly, this offset provides additional slope safety. This is demonstrated <br />through no evidence of slope failure during the life of the pits which have used similar <br />techniques in the same general area. However, a failure would be governed by the internal angle <br />of friction of the material. This would limit the failed slope to an angle of 38 degrees or <br />~1.3H:1 V. This failure would not only stay within the permit area, it would stay within the final <br />slope envelope. <br />The maximum total tonnage sold from the site in any one calendar year is 378,750 tons, though <br />the expected annual average is 252,500 tons. The raw material will be sold in three products: <br />road base, concrete, and asphalt. A break down of the product tonnages and mined tonnages can <br />be seen in Table D-1. The total permit area is 161.86 acres. A breakdown of the estimated areas <br />is included in Table D-2. Both topsoil and overburden maybe sold onsite on an as needed basis, <br />however United Companies commits to keeping enough material onsite to be able to reclaim the <br />site. The amounts of topsoil and overburden sold are secondary commodities and are not <br />therefore included in the table below or the annual tonnage sold from the site. <br />Anderson Pit August OS D-2 <br />