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ilr/iC! <br />'1. <br />COLORADO <br />1A <br />State.co.us Executive Branch Mail - Fwd: shop location <br />Hello - <br />Please file this email as follows: <br />Permit #: C- 1981 -014 <br />Class Name: General Documents <br />Doc Name: E -mail from Dr. Corley regarding subsidence at the mine shop <br />Doc Type: General Correspondence <br />Thanks, <br />Rob <br />George, John, David, and Rob, <br />We received yesterday the copy of A] Weaver's shop report dated Dec. 12, 2013, including the map titled Figure 1 Corley <br />Mine Shop Building Location Map. We have a few thoughts about this report. We believe that the shop is correctly <br />located on this new map, but we would question the assumption in the report that the maximum angle of draw is 29 <br />degrees. The angle of draw was never measured for this strata in this location. i believe that the inclusion of the 29 <br />degree amount in the permit is only an estimate or prediction for the actual angle of draw, and the actual angle of draw <br />could be different. Now after subsidence has occurred the angle of draw will never be known. <br />However, since this report map is based on the Southfield Mine Permanent Closure Map which is know to contain <br />errors such as the location of the monitoring well MW 16, and since it is impossible to check today the actual extent or the <br />elevation of the underground mining, we have located the shop on two other Southfield Mine Maps: Map 12 and Map 17. <br />These two maps utilize apolyconic projection coordinate systemwhich is different fromthe coordinate systemof the <br />Southfield Mine Permanent Closure Map. Since we could not duplicate this polyconic coordinate systemwe have had to <br />rely on georeferencing the shop location from the distances of the shop to known section and quarter corners shown on <br />Map 12. These two maps also have 5 ft. contour lines. The SE corner of the shop coincides with the 6205 ft. contour line. <br />The surveyed elevation of the SE corner of the shop is 6201.3 ft. or 3.7 ft. lower in 2013 than indicated by the 1989 <br />Southfield contour map. This would indicate that subsidence of the shop has occurred. I know of no other premining <br />elevation data that is available. <br />Doug Corley <br />https: / /mail.g oog le.conVmai I /u /0 / ?ui =2 &i Ire29129fcb5 &viev�-- pt &search =i nbox&th= 143699727688ccd2 1 /1 <br />