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r~ ~J Coulson Excavating Company, Inc. - Bonser Gravel Pit Exhibit E -Reclamation Plan Construction Procedure A detailed construction procedure is given here to develop the basis for the quality assurance plan (Appendix 1) and provide the operators with a step by step schematic plan that will guazantee a quality compacted liner. After approximately 23 ac of the pit has been mined out the next step will be to excavate approximately 2 - 3 ft of liner material (weathered Pierre shale) from the bottom of the pit (borrow area). The material will be stockpiled adjacent to the borrow azea (see Figure 1: Exhibit E). In order to maintain moisture content, the stockpile is to be watered periodically. The pit walls will be bladed to a 2:1 slope and the slope material will be back filled into the azea previously occupied by the borrow material. The newly graded slopes will then be compacted with the bulldozer in order to create a stable substrate for the liner. The next step is to install drain file /horizontal pumping well that will keep the water table sufficiently low so as to allow installation of the lifts on top of a completely dry substrate. The drain file trench will be installed approximately 4 ft above the gravel and weathered shale wntact. The trench will eaKend down 1'ft into the weathered shale for a total depth of 4-ft (see Figure 2: Exhibit E). The well will be constructed with 4 in. drain file that will be back filled with gravel. The drain file will be tied in to pumps that will serve to de-water the pit during construction of the compacted liner. Construction of the liner will not begin until the pit is completely dry. The next step will be to spread the liner material over the area to be lined to a depth of 2 ft. A sheep's foot roller will then compact the lift by making no less than four passes over the entire surface. The moisture content of the soil will be tested just prior to compaction of the first lift. ASTM Method D-4643 will be used to detemtine field moisture content (see Appendix I). It is expected from earlier field moisture content measurements that field moisture conditions are 3.4 % wetter than optimum, The lift will be allowed to dry to the point of optimal moisture before compaction will begin. The field inspector will calculate the drying rate as the day progresses and measure field moisture content. Water will be added or lifts will be allowed to dry as needed to maintain optimal moisture content throughout the compaction process. The volume of water needed to raise the moisture content by I % has been calculated to be about 7546 gallons for 2 acres. This calculation is given in Appendix I, as well as a step-by-step calculation procedure for the same calculation with different acreage. Appendix II contains tables for 0.5-5 acre 1 ft lift water volumes and estimates of water losses throughout the day for each month of the yeaz. Evaporative soil water loss tables were calculated based on a rate 30%greater than pan evaporation. Pan evaporation for the area is 40 in yr""~ (NOAA, 1982) The 30% increase is due to albedo effects (Hillel 1980). The water loss tables are to be used as a general guide to estimate the amount of water to have on site to moisten liner material if it becomes too dry, or to estimate the amount of time the lift needs to dry if the material is too wet. Moisture content measurements aze to be used to estimate moisture loss and to determine ho~v often moisture content measurements should be made. For example, if the soil needs to lose 3%mois[ure content before compaction and field personnel determines form the charts in Appendix