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EXHIBIT D MINING PLANT a. The Method of mining at all stages of the operation will be Open Pit removal of gravel. b. Earth moving will be accomplished with a bulldozer, drag line, and front end loader. The depth of the gravel pit will be approxi- mately 10 feet average, and the drag line will be used when necessary to remove gravel which is below the subsoil water level. The gravel in the bottom of the pit is below sub- soil water level only in years of heavy snow runoff. c. There will be n~ water diversion and impound- ment, although, as mentioned above, during wet years the underground water table in the area will rise to a few feet above the bottom of the pit. (the subsurface water table ranges from approximately 3 feet below the surface in an extremely wet year to approximately 20 feet below the surface in an extremely dry year in this area. In an extremely wet year this re- sults in a few feet in the bottom of the pit being filled with water, but no such water shall used for any purpose, since the County has no use for such water and no rights to such water.) d. The size of the area to be taorked at any one time would be approximately 3 to 10 acres. There are no separate pits within the main pit area, and gravel is removed only when needed. Gravel is and will be removed from different areas of the pit in order to insure that the gravel pit, at the termination of its gravel extracting life, will be compatible with the use as a wild life habitat. This will include making certaih that the perimeter of the pit is irregular, so that it would adapt to various wild life, especially ducks and geese, and other migratory water fowl. The sides of the pit shall be sloped in a ratio of 5 to 1, which is considered a slope which is appropriate for wild life habitat of this type. The operation does not include overburden spoils and topsoil stock piles, since there is no overburden or topsoil in this area. There are 2 or 3 crushed gravel stock piles which are depleted as they are used for necessary County projects, and are located as shown on Exhibits B and C. The area of excavation is as shown on Exhibits B and C also. e. This gravel pit operation is not subject to different phases or stages. It is estimated that gravel will be extracted by the County from this gravel pit on an as needed basis for a maximum of 90 years, since such gravel is only removed sporadically. This gravel pit operation was in existence prior to January, 1976, so no fugitive dust permit is required. The~ore body to be removed is almost entirely gravel, and the thickness of the gravel deposit is estimated to be approximately 30 feet, al- though only approximately the top 10 feet will be removed. The nature of the stratum immedia- tely beneath the material to be mined is believed to be the blue clay formation which underlies most of Rio Grande County. i ._