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of draw. Slopes facing towards the mined-out area will result in larger angles of draw. At the present time, the <br />influence of irtegulaz topography on the angle of draw has yet to be quantified. <br />It is anticipated that the irregular topography in the permit azea will cause some variation in the angle of draw. This is <br />consistent with preliminary observations from the longwall subsidence monitoring area above the No. 5 Mine where <br />the steeper slope facing away from the gob area had a significantly reduced angle of draw. Three (3) draw angles <br />along monitoring lines, as shown on the Subsidence Monitoring Map (Map 3l, were measured. The results of these <br />measurements are shown on Table 86, Draw Angle Versus Slope and Orientation. <br />A careful review and evaluation of the site-specific subsidence data and the site-specific geotechnical data determined <br />the predicted angle of draw for the No. 5 and No. 6 Mines. This data was compared with research data from York <br />Canyon, New Mexico (Gentry, Stewart, and King, 1981), Kemira Colliery, Australia, (Kapp, 1974), Paonia, Colorado <br />(Dunrud, 1976), and Utah (Allgaier, 1982; and SUFCO, Personal Communication, 1986). The geotechnical <br />environment in the permit is similaz to that found throughout the CEC Mine complex as well as the various coalfields <br />of the western United States. An angle of draw of 19° is predicted as a conservative average draw angle for the permit <br />area. <br />SUBSIDENCE CONTROL PLAN <br />CEC has prepared this Subsidence Control Plan to outline the proposed measures that may be taken, if required, to <br />restore any affected structures or resource lands to their pre-subsidence condition. This section specifically addresses <br />the structures present in the permit area. The only renewable resource lands potentially impacted by subsidence are <br />the surface and subsurface water resources. The proposed mitigation measures for the surface and subsurface water <br />resources are discussed in Section 2.05.6, Mitigation of the Impacts of Mining Operations. <br />• Mine Facilities ~resent(v Undermined) <br />The mine facilities in the permit area that aze presently undermined include mine roads, power lines, water lines, the <br />railroad spur, the coal storage silo, and the coal transport facilities. These facilities are presently located over <br />development entries (mains and submains) which are designed to remain stable for the life of the mine. These areas <br />have been protected against subsidence damage by ensuring that sufficient coal was left in place to prevent subsidence <br />in the area. If subsidence was to occur and the structures or facilities were to be damaged, they will be repaired or <br />replaced at the option of CEC. <br />Mine Facilities (~'o Be Undermined) <br />The mine facilities under which planned mining will take place include CEC Corporation facilities as well as those of <br />Trapper Mining, Inc. The CEC surface facilities that will be undermined during the 1998 - 2003 permit tens include: <br />(1) old shop and storage area, (2) ponds SH-Pl and SH-P2 and associated ditches SH-D2 and SH-D3, (3) a rock dust <br />tank, (4) contractor staging area, (5) storage and wood shop, and (6) Okie Plaza well. It is anticipated that subsidence <br />effects may necessitate minor repairs to these facilities. A general lowering of the ground surface with grade changed <br />and minor cracking may occur. The old shop will be monitored, and if it becomes unsafe, it will be repaired or <br />removed. Pons SH-PI and SH-P2 and ditches SH-D2 and SH-D3 will be monitored closely during subsidence. Pre- <br />and post-subsidence surveys and monthly inspections between surveys will be conducted. Any damage will be <br />promptly repaired. The rock dust tank is no longer in use so no effects are anticipated there. The tank will be <br />monitored, and if any safety concerns are identified, it will be repaired or removed. No facilities except an empty <br />water tank are located at the contractor staging area, so no effects are anticipated. The trailer at the storage and wood <br />shop will be monitored to insure that it does not become unsafe. The Okie Plaza well will not be undermined until a <br />• revision is approved by the Division for elimination or replacement of this monitoring well. Surface mine facilities <br />belonging to Trapper Mining, Inc. include reclaimed surface land, topsoil stockpiles, and small stock ponds. <br />Permit Renewal No 3 2.05-63 7/15/98 <br />