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RECEIVEV <br />JUN 0 9 2009 <br />Division . . <br />Mining and <br />MEMORANDUM <br />Date: June 3, 2009 <br />To: Don MacDonald cc: <br />From: Curt Ahrendsen <br />Subject: DRMS Response <br />Don - This is in response to the DRMS letter regarding Technical Revision 40, dated May 22, <br />2009. <br />1. The Periodic Ash Stabilization (Daily Cover) volume used for the year 2008 is 9,688 <br />BCY. However, the volume we used in the analysis is the average of the 2008 through 2004. <br />This is done because the actual volumes have varied from 6,650 BCY to 10,411 BCY and our <br />goal is to be as realistic as possible. Therefore, the actual average annual volume calculated over <br />the 11.8 year period is 8,967 BCY of LTSA soils used as daily cover. This is how the 105,822 <br />BCY volume is derived. Also, because this is calculated using the Excel spreadsheet program, <br />there are minor variances in the final figure. For example, if you multiply 11.8 years times 8,967 <br />BCY per year, the result is 105,811 BCY. The spreadsheet calculated 105,822 BCY because it <br />uses the decimal places also. Therefore, the required volume of LTSA spoils is 105,822 BCY <br />plus 217,648 BCY (volume required for B-Pit final cover overburden layer) equaling 323,470 <br />BCY. <br />2. The volume of remaining Long-Term Spoils soil was calculated by Nagengast Brothers <br />using the new contours of the Technical Revision in early 2008 and was noted as 377,088 BCY. <br />The 9,688 BCY volume of annual daily cover used in 2008 was then removed from the <br />calculated volume leaving approximately 367,400 BCY of soil in the LTSA. The pre-TR40 <br />volume of spoils in the LTSA was 265,372 BCY. The additional useable spoils is 102,028 BCY <br />or an average additional cut of 1.24 feet rather than the 0.88 feet. This results in an approximate <br />excess of 43,930 BCY.