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TRAPPER MINE SWELL FACTOR FOR SPOILED OVERBURDEN/PARTING <br />A factor of 1.25, or 25X swell, was used [o construct Trapper's post-mining con- <br />tour map. This factor has been used routinely in the pas[ a[ Trapper to antici- <br />pate spoil volumes, placement of spoils and rehandle requirements as part of <br />ongoing mine planning. Its validity is therefore supported by actual exper- <br />ience. <br />Corroborating calculations can be provided from Trapper's records of bank cubic <br />yards (BCY) moved by the draglines and [he number of dragline swings ( = bucket <br />loads ) required to move the recorded volumes. These data are presented in <br />Table 1 for the period 1979 through October, 1981. The average number of BCY <br />per swing ( or bucket load ) can be calculated by dividing the total number of <br />swings into the total number of BCY moved, i.e. 48,571,441 BCY r 2,032,756 <br />swings 23.89 BCY per swing ( or per bucket load ). <br />The rated struck bucket size on all three Trapper Mine draglines is-30 cubic <br />yards. Therefore, the swell factor can be estimated by dividing the 30 swelled <br />cubic yards (SCY) per bucket load by [he average bank cubic yards moved per <br />bucket load, i.e. 30 SCY - 23.89 BCY = 1.256. This correlates well with the <br />1.25 factor used for estimating final overburden volumes. <br />