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2. Foundation and Embankment Material Characteristics <br />By examining the pond locations and the soils map, it is apparent that the material for embankment <br />construction will be either two types: <br />1) Those subsoils with coarse fragments (soil unified classification types GC or GM). These are <br />soils 98B, 98C, 98D, 98G or 98H as shown on the soil inventory map of the permit. Table 1 on the <br />following page shows that these soils are either poorly graded gravel- sand -si It or poorly graded <br />gravel -sand clay. <br />2) Those soils without coarse fragments (soil unified classification types SM -SC or SC). These are <br />soils 98D, 98E and 98F as shown on the soil inventory map of the permit. Table 1 on the following <br />page shows that these soils are either poorly graded sand -clay mixture or sand - silt -clay with slightly <br />plastic fines. <br />The material for the foundation will consist of the natural subsoils which are currently being stripped <br />by scrapers and replaced in the backfill. This material is also poorly graded, will have coarse <br />fragments and is classified as a GC soil - poorly graded sand - gravel -clay or GM - poorly graded <br />gravel, sand & silt. <br />The chart on the following page shows the range in strength parameters for each of these soils. For <br />this analysis, a full range of cases will be analyzed, to account for any possible embankment soil <br />and foundation soil which could occur on the site. <br />Samples of the embankment for Pond 008 were taken in January of 2000 and found to correspond <br />to the descriptions given above for SM -SC or SC soil. In place density tests of embankment <br />material were made by extracting a certain volume, replacing the void with a known volume of sand <br />and later weighing the material extracted. The average wet density of the in -place material was <br />found to be 137.3 Ibs /cu.ft. The material was then dried and re- weighed to give an in -place <br />compacted dry density of 118.6 Ibs /cu.ft. The moisture content of the original material was <br />approximately 12 %. This material will be representative of the material used for all other dams on <br />the site. The SM -SC or SC soils are preferred for the embankment since the clay content results <br />in better cohesion for dam construction. The lower foundation material was also sampled and found <br />to also correspond to the descriptions given above for SM -SC or SC soil. The material was much <br />sandier and had less clay. The same density test was performed on this material which resulted in <br />an in place wet density of 112.3 Ibs /cu ft. The dry density was much lighter - 84.8 Ibs /cu. ft. The <br />high water content of this material (24 %), is due to natural water present in the sandy subsoil. <br />Attachment 2.05.3(3) -15 -4 <br />