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MINING PLAN <br />Overburden Stripping and Storage <br />Much of the overburden present in the initial mining area (pre-amendment permit <br />area) was consumed in the construction of the plant site. To create a plant site that was <br />high enough above the elevation of the adjacent land to be protected from all but the <br />most significant floods required a very large amount of overburden. This overburden will <br />not be removed once the plant site is closed, but will remain in place. It could serve as an <br />excellent area for a building site in the future. <br />Other stripped overburden will either be temporarily stockpiled near locations <br />where it will be used as backfill, or it will be disposed of immediately into an area that <br />needs to be backfilled. Thus, overburden storage should not become a serious problem. To <br />reduce the amount of land that might require augmentation where groundwater is <br />exposed, use of the overburden to backfill mined areas is a highly beneficial use. <br />Although some of this material could be sold as a product, as a rule the overburden <br />contains a considerable amount of clay which greatly limits how it can be used. Thus, <br />using it as backfill is an excellent use. <br />The overburden exists not only directly above the gravel but usually immediately <br />above the ground water level. At certain times of the year (late winter) the ground water <br />level may decline to the point where there is some gravel above the ground water, but <br />generally the top of the water table is located at the interface of the overburden and <br />gravel. Thus, material located between the bottom of the topsoil layer and the gravel <br />layer is considered overburden, even though it may also be considered subsoil. <br />On this site overburden does not appear to have much value as a growth medium <br />in the same sense as topsoil. It often is saline and/or alkaline, or it contains other <br />properties that does not make it suitable for use as a dryland growth medium. However, <br />disposing of this material as backfill on land where groundwater is exposed and wetlands <br />will be created is a suitable use of the overburden. The leaching effect in a wetland <br />situation will remove much of the undesirable chemistry and the constant exposure to <br />hydric conditions makes it useful in wetland situations. Many wetland plants are also <br />adapted to such conditions. <br />In the event there is more overburden than there are locations where it can be <br />disposed of (very unlikely), the material will either be sold or it will be used to create <br />slopes within the future slurry wall area. The latter approach is preferred. For more <br />information on this subject, please refer to the Reclamation Plan (Exhibit E). <br />Pueblo East Pit Amendment Exhibit Page 7 <br />