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<br />David Berry -17- June 20, 1996 <br />2.1 SURFACE CONDITIONS <br />WESTEC observes that no surficial springs or signs of <br />ephemeral streams were noted within the footprint of the <br />proposed waste pile in September of 1995. Because September <br />is near the annual ground water low stand, BRL should <br />reexamine the footprint of the proposed pile at the normal wet <br />period of the year, during May or June. <br />The reference to J.E. Stover and Associates (Jewkes, 1995) on <br />page 2 of the Volume IV text was meant to imply that no <br />surficial water or signs of ephemeral streams have been noted <br />within the limits of the proposed coal mine waste bank during <br />the year (low or high groundwater season). The site has been <br />visited on many occasions by representatives of J.E. Stover <br />and Associates, and we believe their observations to be <br />accurate. During the WESTEC site visit in September 1995 and <br />again in November 1995, no surficial water or ephemeral <br />streams were observed, but more importantly, no signs of these <br />phenomena were observed (i.e. stream erosion features). <br />4.1.4 Runoff Control Ditches <br />WESTEC states; "The 35-inch maximum riprap size recommended <br />for these side ditches is large, compared to ditch size and <br />flow depth. This requirement provides for the stability of <br />the material under loads transferred by the flowing water and <br />for mass stability of the riprap itself. It is found that <br />placing riprap this size is not practical, it is suggested <br />that the Dso material size, 24 inches, be placed and secured <br />using grout." <br />If the riprap is to be placed and secured with grout, rather <br />than with the traditional gradational filter blanket, a <br />specification and drawings for the riprap grading and grout <br />placement shall be included within the permit documentation. <br />Further, since a grouted pan cannot adjust to consolidation of <br />the underlying materials, it is important that the foundation <br />beneath the channel pan be firm. Therefore, BRL shall commit <br />to the inspection and density testing of the prepared subgrade <br />of the grouted riprap pan. <br />The above referenced sentence is an excerpt from paragraph two <br />of section 4.1.4 of Volume IV. It was meant as a contingency <br />to the large gradation required in some of the diversion <br />ditches specified in the report. Specifications and drawings <br />were not included because it is not known at the time of the <br />report if the contingency is required. We believe the design <br />to be accurate and provided the contingency in the case that <br />field conditions require it. The decision would be made at <br />the time of construction, and the DMG notified of the design <br />changes. If the grouted rip-rap option is used, BRL is <br />