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<br /> <br /> <br /> <br /> <br />t <br />1 <br /> <br /> <br />1 <br />1 <br /> <br />lJ <br />lJ <br /> <br /> <br /> <br />1 <br />2. Material SamPlina and Characteristics <br />Although no detailed maps are available for the original contour <br />prior to mining, a fairly accurate picture of the pre-mining <br />contour can be obtained from old photographs, site measurements <br />and studying the terrain above and below the fill. From this <br />information, it is seen that the existing cut for the portal area <br />is approximately 60 feet high at its highest point and the <br />original slope of the ground in this area was approximately <br />1.OV:1.OH. <br />Exhibit 1 shows a cross-section of this portion of the bench <br />area. Also shown is the area of backfilling to eliminate the so- <br />called highwall. The only reasonably available fill to do this is <br />that fill located below the bench which was blasted from the wall <br />in the first place prior to the reclamation laws. <br />Samples of the fill were collected in 5 gallon buckets from <br />various locations along the pile. The slope was walked over its <br />entire length to determine variability. Material was excavated to <br />a depth of 2.5 feet for sampling. In place density tests were <br />made by extracting a certain volume and later weighing the <br />material. The average wet density of the in-place material was <br />found to be 128 lbs/cu.ft. and the dry density was found to be <br />116 lbs/cu.ft. <br />Samples of the material were submitted to Fox Associates of <br />Colorado, Inc. which performed a particle size analysis of the <br />material, a moisture-density analysis (proctor) and direct shear <br />tests in order to determine the strength properties of the fill. <br />The results of these tests are included at the end of this <br />report. <br />Over 150 pounds of material was submitted for analysis. The <br />material was screened using a number 4 sieve. This screen is <br />approximately 1/4 inch in the size of its openings. Approximately <br />54 $ of the material was larger than this opening. It is felt <br />that this is representative of the distribution in the fill <br />because some of the larger material on the surface was avoided <br />for sampling, however, the inner depths of the pile probably <br />contain a greater amount of fines due to the manner in which the <br />pile was created. These two effects should cancel, making the <br />samples representative of the overall fill. The full particle <br />size breakdown is enclosed in the report from Fox. <br />1 <br />