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Revised 11/15/81 <br /> Calculations indicate that maximum expected vertical subsidence is three <br /> to four inches at the surface. The type of subsidence phenomenon <br /> expected, if any, at the Maxwell Mine, is trough subsidence. <br /> Characteristically, trough subsidence entails primarily vertical <br /> movement and no significant horizontal movement. Due to the low amount <br /> of predicated vertical movement, very little or no horizontal movement <br /> is expected. <br /> Review of the surface structures which could possibly be damaged <br /> indicates that no structure will be materially affected. Houses and <br /> buildings located on alluvial material will not be cracked or otherwise <br /> damaged by this slight amount of surface subsidence. Little if any <br /> damage or cracking of the highways and roads will occur by this slight <br /> subsidence. Power lines, utility lines, and other miscellaneous <br /> structures will not be affected by slight vertical movement. Minor <br /> subsidence of three to four inches will not affect the hydrologic regime <br /> of the area. Disruption of aquifers and the essential functions of the <br /> alluvial valley flow and the Purgatoire River will not occur. The <br /> Subsidence Control Plan Map (Map 17) shows the location of the mine <br /> workings and their relationship to structures located on the surface. <br /> Generally, the structures which may be affected would not be materially <br /> damaged. The effect on the renewable resource lands located in the <br /> Purgatoire River area is expected to be very slight also. Comparisons <br /> with the conditions which exist in the Maxwell Mine have been made with <br /> the adjacent Allen Mine operation. There are no discernable subsidence <br /> features at the Allen Mine. If any subsidence of the surface at the <br /> Allen operation has occurred, it has not created any significant or <br /> apparent impacts on the renewable resource lands or the structures <br /> located in the areas which have been affected. CF&I Steel Corporation <br /> does not anticipate any material or different effects of subsidence at <br /> the Maxwell Mine. Therefore, subsidence is not expected or planned at <br /> the Maxwell Mine during the term of the permit. However, calculations <br /> have been made to ensure that continued support of the structures and <br /> renewable resource lands are continued at the Maxwell Mine to negate any <br /> potential effects on the environment. <br /> 2.05-48 <br />