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standard proctor. Compaction tests will he run on approximately every 2,500 <br />• ~ cubic yards of material placed in the embankment... Results of these tests will <br />be kept on file at the mine engineerfng office and will be available for <br />Inspection if requested. Both [he upstream end downstream slopes slopes of [he <br />embankment will be 3h:iv or flatter. <br />During the 100-yeer storm, with the emergency spillway functioning as designed, <br />there will be 4.1 feet of freeboard. Taking into account 1.0 foot settlement, <br />there will still he 3.1 feet of freeboard. <br />p horizontal drainage system according to Mirafi Fabric Filter design <br />guidelines, will be placed as shown on Exhibit 13-4. Using the "Design <br />Guidelines for Subsurface Drainage Structures" by Xirafi Fabric Filters, the <br />drainage blanket should be a minimum of one foot thick. The granular material <br />may have 100 percent passing the 3/8-inch sieve, 70 percent passing the #8 <br />sieve, 30 percent passing the #40 sieve, and less than 10 percent passing the <br />#200 sieve for a permeability of 2 ft/day. <br />• The toe drain should be placed as shown on Exhibit 13-4. The underdrain system <br />should consist of a series of six-inch diameter, slotted PVC pipes surrounded by <br />a minimum of six inches of free draining granular materiel. The granular <br />material should extend up to the bottom of the next bench and should contain <br />less than 3 percent passing the #200 sieve and more than 50 percent retained on <br />the #4 sieve. the granular drainage materials should be wrapped with a filter <br />cloth such es MirafS 14DN or an equivalent fabric approved by the soils <br />engineer. <br />The drainage system along the downstream toe of the dam should extend across the <br />natural channel to en approximate elevation of 6775 feet or 40 feet <br />perpendicular to the center line of the proposed dam; the exact location will <br />have to be determined in the field when the enact elevation of the channel is <br />known. An adequate layer of fill materiel should cover the dreinege blanket in <br />order to maintain its integrity. Based on the site geometry, the blanket <br />drainage system will be approximately 200 feet in length; however, the actual <br />• dimensions should be determined in the field. <br />13-3-11 Revised 06/19/95 <br />