2011-08-30_REVISION - C1981028 (2)

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TO ROB ZUBER FROM: JANET BINNS / SUBJECT: KEENESB DATE: 8/30/2011 CC: DAN HERNANDEZ INTEROFFICE MEMORANDUM TION COST UPDATE Rob, I received your note and have spoken with both Susan B. and Jim Stark regarding swell factors. None of us can locate where the 1.266% swell factor of BCY to LCY for Sand -Damp came from in the old version of CIRCES. If one thinks it through, sand does not swell by one quarter of its volume when disturbed. Jim confirmed with me that the current CAT handbook (edition 40) calculates BCY to LCY swell as 1.124. This is the factor that I used for spoil swell. The automatically generated word document sheets incorrectly put CCY in the "initial volume" units. It should reflect that I had entered Bulk Cubic Yards. I was able to correct this on Task 05A and Task 05B. Tasks 7a, 10, 40 and 45a are specific to topsoil activities. I used "Sand -damp" as the material for topsand tasks, but I used the CCY to LCY swell factor. The CCY to LCY swell is 1.060. I chose the different factors since the long term spoil pile has more clay than the topsand, and gets driven over by scrapers and compacted more over the years of storage. The topsand piles are relatively left alone and not compacted by equipment. CEC pulls the topsand off the end of the pile when they are replacing it on regraded areas. With CIRCES and material weights, we choose the material that best fits the material we know to be on the mine site. It's not exact, but I think we get material qualities fairly close. "Sand - damp" appears to be the closest choice to the spoil and topsand materials found at the Keensburg mine. So, the only change I made to my estimate was revising the word documents for Task 05A and 05B to reflect that the swell factor is for bulk cubic yards (BCY) to loose cubic yards (LCY).