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Kaidenbach, Tom <br />From: Kaldenbach, Tom <br />Sent: Thursday, January 27, 2011 4:03 PM <br />To: 'Welt, Kathy' <br />Subject: RE: West Elk Mine (C-80-007), Spring 2010 subsidence report review <br />Kathy, <br />The value in the table for ground elevation at each station is the station elevation shown in <br />Appendix B of the subsidence report. <br />Each value in the table for the top of the E Seam is the interpolated value on Map 17 in the <br />permit application at the point on the panel edge where a line drawn normal to the panel edge <br />intersects the station. <br />Angle of draw is calculated arctangent(horizontal distance/vertical distance). <br />No values are used in Figure 1 as it is a schematic cross-section showing only the geometric <br />relationships of right triangles used for calculating angle of draw. <br />Angle of draw is the angle between a vertical line extending from a point on the longwall <br />panel's edge and a line extending from that point in the direction normal to the panel edge <br />to the point at the land surface located at the limit of detectable subsidence. (My wording <br />is different, but the angle is the same angle that is described on page 2.05-105 of the <br />permit application),and in publications by the National Coal Board and Syd Peng.) <br />No values are used in Figure 1 as it is a schematic showing only the geometric relationships <br />of right triangles used for calculating the angle of draw. <br />Tom Kaldenbach <br />Environmental Protection Specialist <br />Colorado Division of Reclamation, Mining and Safety <br />1313 Sherman St., Room 215 <br />Denver, CO 80203 <br />Phone (303) 866-3567, ext. 8128 <br />-----Original Message----- <br />From: Welt, Kathy fmailto:KWelt(darchcoal.coml <br />Sent: Thursday, January 27, 2011 3:02 PM <br />To: Kaldenbach, Tom <br />Cc: Hernandez, Daniel <br />Subject: RE: West Elk Mine (C-80-007), Spring 2010 subsidence report review <br />Tom, <br />Could you provide the reference(s) that were used as the basis of the values used in your <br />calculation so that I can provide them to Wright Water Engineers et al for their review? <br />Thanks, <br />Kathy ' <br />From: Kaldenbach, Tom [Tom.Kaldenbach@state.co.us] <br />Sent: Thursday, January 27, 2011 3:43 PM <br />i