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7) Small Exemption Areas <br />Three small area exemptions are planned for the amendment area. These are shown on Map <br />2.05.3-12 and are located on the westernmost portion of the permit area where the terrain is <br />undulating and these areas cannot be made to drain to any sediment pond. The areas are 2.1 <br />acres, 2.6 acres and 0.9 acres, respectively. The alternative sediment control measures for <br />these areas consist of earthen berms of 2H:1 V sideslopes with a minimum top height of 3.0 feet <br />installed at the bottom of the exemption area to channel the runoff into a 30' wide gravel berm <br />section with filter fabric. This section will be installed in the lowest 30' section of the exemption <br />area and will serve to filter sediment out before gradually releasing the water through the gravel <br />embankment. A schematic of this installation is shown on the following page. The filter fabric to <br />be used is Mirafi Filterweave UV fabric or equivalent. The gravel embankment will consist of <br />minus 3" durable rock. A portion of the filter will be buried below the embankment as shown and <br />a height of 2.0 feet above the filter will be used to handle very large events. <br />Two additional small area exemptions (#4 & 5) are planned for the Benson East property that is <br />in Section 31. See Exhibit 2.05.3-19. These two areas are on the north side of a ridge line and <br />water runoff can not be diverted back to a sediment pond as the mining pit advances toward the <br />area. To control the water off these two small areas, a number of staggered contour catchment <br />v-ditches (approximately 12 inches deep) will be plowed along the hillside to catch runoff and <br />keep the water from gathering volume. In addition to this, a silt fence and/or straw bale filters <br />will be placed at the further most drainage channel to filter the water before it leaves the mine <br />disturbance area. After mining and reclamation is completed in this area, which should be in <br />year 2003, it is anticipated that an appropriate ditch system will be constructed to channel the <br />water to an approved sediment pond. <br />(REVISED ~~-26-Oi ; Attachment 2.05.3(3) -10-119 <br />