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The connected six to eight inch pipes were installed flat at invert elevation 4849.0', no slope, and daylighted on the north <br />end of the west side eight inch pipe. The pipe dead ended within the existing steep embankment. A swale, <br />approximately fourteen feet in length, was cut through the embankment at a two horizontal to one vertical (2:1) side <br />slope for the underdrain water to free flow to the Little Dry Creek floodplain. Type L riprap was Imported and placed to <br />protect the Swale sides and bottom from erosion and sloughing. Civil Resources verified that there is positive drainage <br />available between the underdrain outlet to the Little Dry Creek low flow channel. <br />3.0 CONSTRUCTION ADJUSTMENTS <br />The approved TR-3 design showed both the south and west pipes daylighting at the southwest corner of the pit and then <br />free flowing through a constructed Swale to Little Dry Creek. Due to construction during the highwater season, swale <br />excavation from these outlets to Little Dry Creek would have required excavation across wetiands through standing <br />water. The pipe system was redesigned without changing the basic pipe layout or pipe invert elevations. The south side <br />pipe remained unchanged in size and location except that it connected to the west side pipe which was upsized from <br />four to eight inch diameter. The west side pipe did not change in location or invert elevation but the pipe diameter was <br />changed from tour inches to eight inches. Both pipes were designed to daylight on the south end of the west pipe but <br />now the combined flow daylights on the north end of the west pipe and overland flows to the Little Dry Creek low flow <br />channel. <br />4.0 <br />The Heit Pit Underdrain pipe system was constructed according to the design plans excepting the construction changes <br />due to the elevated wetlands water west of the southwest pit corner. The constructed underdrain system has adequate <br />capacity to convey calculated flows to Little Dry Creek and thereby limit groundwater mounding resulting form the Heit <br />slurry wall. The contractor utilized appropriate observed construction practices and material specified per plans. <br />As per the mine permit, water monitoring will continue during the operation and dewatering of the mine to determine if <br />mounding is occurring. <br />J:\SW Investment Group -123Weit Properl (Record DrawinglConstruclion Repod.doc <br />Construction Report - Heit Pit Underdrain - 2 - August, 2007 <br />