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consistently ranges from 300 to 400 feet above coal bed 1 throughout the area of the existing <br />leases as well as in the proposed lease area. Subsidence is directly affected by the thickness <br />of the coal seam mined (4.5 to 7 feet), the overburden thickness, and overburden <br />composition. Subsidence will show as stress cracks up to a couple of inches wide. <br />A condition of approval of National King Coal's mine permit revision for Lease C-29125 and <br />subsequent permit revisions by Colorado Division of Minerals and Geology was that subsidence <br />would be monitored on a quarterly basis. The purpose of the monitoring was to determine if any new <br />subsidence was occurring and if the Huntington Ditch was being affected in any way. According to <br />National King Coal records (Second Quarter Monitoring, 1999), there are no new subsistence cracks <br />in the areas requiring monitoring to date. All areas, which lie above underground support pillars that <br />have been removed, continue to be monitored on a quarterly basis for evidence of material damage to <br />the surface. <br />Colorado Division of Minerals and Geology rules 2.05.6 and 4.20 require that "underground mining <br />activities shall be planned and conducted so as to prevent subsidence from causing material damage <br />to the surface." Material damage is defined in Rule 2.05.6 with respect to subsidence as changes <br />which prevent restoration of affected structures and with respect to renewable resource lands; <br />changes which disrupt an aquifer, or a recharge area to an aquifer, which serves as a beneficial use of <br />water; or changes which prevent restoration of productivity for agricultural lands. <br />There are no active faults adjacent to or on the project area (Zapp, 1949). No other geologic hazards <br />are known to exist. <br />No known fossils of significance have been found on or near the project area. The Mesa Verde <br />Group yields sparse faunas of both marine and non -marine elements. No study exists with specific <br />reference to the botanical fossils related to the Menefee coals nor on the non -marine invertebrates on <br />the associated units (Fischer, 1981). <br />WATER <br />The topographic surface of the project area consists of a plateau between East Alkali Gulch, <br />Hay Gulch and "No Name Gulch" to the southeast. These are ephemeral drainages of <br />variable gradient. Surface water within these drainages occurs as a result of seasonal spring <br />runoff and following summer/fall storm events. The project area is not in a major ground <br />water recharge area. Mining activity in the project area would occur approximately 40 feet <br />above the piezometric surface, which is static water level. <br />VEGETATION <br />13 <br />