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Subsidence Evaluation for the <br />Exhibit 60E South of Divide and Dry Fork Mining Areas Page 38 <br />12.0 IMPACTS BENEATH THE MINED E COAL SEAM <br />Based on mapping and observations by Dunrud in the B -seam of the Somerset Mine, impacts to <br />the coal and rocks below the mined coal bed are expected to be limited to about one mining <br />thickness. There is no expected mining impact to the underlying D Seam because its top <br />commonly occurs at a mining thickness below the base of the E -seam Furthermore, impacts to <br />the floors of the mine workings are expected to be limited to the chain pillars, because the floors <br />of the longwall panels will be loaded with caved roof rocks and overlying strata before <br />deformation in the floor can occur. <br />Floor heaving, pillar punching (the pillar punches into the floor and roof rocks), and squeezing <br />(also known as plastic flowage, see Dunrud 1976, p. 36) are the only expected deformations in <br />the immediate mine floor, which commonly consists of impure coal, shale, sandstone, and <br />claystone. Deformation in the floors of the chain pillars is expected to occur after the longwall <br />panel is mined and the pillars begin to yield. <br />J <br />0 <br />831 - 032.810 Wright Water Engineers, Inc. <br />