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• 2.05.6(6) <br />The Operator has acquired the right to expand its B -Seam mining <br />operation into Sections 16 and 20. The mine plan area in Section <br />20 will undermine the upper reaches of Lone Pine Gulch. Sections <br />D -D and E -E shown on Map 15 present the anticipated angle of draw <br />for the proposed B -Seam Mine plan. <br />Section D -D is taken just above the confluence of Lone Pine Gulch <br />and a tributary to Lone Pine Gulch. This portion of Lone Pine <br />Gulch has been undermined by West Elk in both the B -Seam and F- <br />Seam. <br />Section E -E is taken in the upper reaches of the Lone Pine Gulch <br />tributary. This area has been undermined by West Elk's F -Seam and <br />the Bear No. 2 Mine C -Seam. <br />Subsidence from any of the mining performed under Lone Pine Gulch <br />could impact the flow of water through the drainage. However, Lone <br />Pine Gulch and its tributary are very steep so subsidence would not <br />be expected to reverse the grade of the drainage. The flow through <br />• the drainage could temporarily be effected by a subsidence crack, <br />but the crack would be expected to heal fairly quickly so the <br />surface drainage pattern would be naturally restored. <br />• <br />The minimum overburden depth in the Section 20 mine plan area is <br />about 500 -feet. Therefore, chimney collapse should not be a <br />concern. As stated previously in this section, subsidence could <br />have small effects on both existing and new landslides. However, <br />there are no long term impacts expected to be caused by subsidence <br />in this area. <br />Map 6 presents the projected extent of subsidence in Section 20. <br />There are no structures or renewable resource lands located in the <br />area to be affected in Section 20. Spring G -26B is over 700 feet <br />southwest of the projected extent of subsidence. Because there are <br />no structures or renewable resource lands in the Section 20 mine <br />plan area, no special mine plan design features are incorporated to <br />control subsidence. Additionally, no subsidence monitoring will be <br />performed in the Section 20 mine plan area. <br />2.05 -63b Rev. 09 -26 -94 <br />