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-~ <br />~II'~~II~II~~~~~ ~I~ <br />STATE OF COLORADO <br />DIVISION OF MINERALS AND GEOLOGY <br />Depanmenl of Natural Resources <br />1313 Sherman 51., Room 21 5 <br />Denver, Colorado 80203 <br />Phone U03) 866-3567 <br />FAX: 13031 8 3 2-81 06 <br />DEPARTMENT OF <br />NATURAL <br />RESOURCES <br />DATE: January 23, 1995 Roy Romer <br />Governor <br />TO: Susan Burgmaier ~ IamesB Lochhead <br />Eweculive Director <br />FROM: Erica Crosby ~G Michael B. Long <br />Division Director <br />RE: Yoast Mine (C-94-082) <br />Bond Estimate <br />Susan, I have the following concerns regarding the cost estimate <br />for the Yoast Bond Estimate: <br />1. On Tab 25 page 3 under Backfilling and Grading, Seneca states <br />that a swell factor of 12$ was used based on studies in <br />Chapter 20. No studies could be located in Chapter 20 <br />regarding swell factors, it only stated that a 12~ swell <br />factor was used in determining post mine topography at the <br />Yoast Mine. In Tab 21, it appears that the overburden <br />consists of 1/2 clay and 1/2 sandstone. The Division believes <br />for this composition of material, a swell factor of 17$ is <br />more accurate ( 50$ rock 50$ earth in the Caterpillar <br />Performance Handbook). <br />Please submit more information confirming Seneca's 12$ swell <br />factor, or change the bond estimate to reflect a 17$ swell <br />factor. <br />2. The Division was unable to calculate the volume of material <br />associated with the worst case disturbance of 1997. Please <br />provide the Division with the working maps, SWAMP and RANGER <br />data sheets used to predict the worst case disturbance. <br />3. Tab 19 page 8, Seneca states that spoil sampling will be <br />conducted after final grading is completed and prior to soil <br />replacement. Please include a cost for spoil sampling in the <br />bond estimate. <br />4. Tab 19 page 8, Seneca states that areas which are severely <br />compacted will be ripped on the contour, and topsoil replaced <br />from stockpiles or direct hauled within one year after filing <br />grading is completed... Please include an estimated cost for <br />additional ripping mentioned above. <br />