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be compacted in thin lifts in order to achieve this compaction. This compaction also serves to <br />greatly improve the slope stability of the permanent pile. <br />6) A piezometer is located at the downstream edge (north of the north toe) of each pile to <br />monitor the water quality of any water that may emanate from the piles. These samples will be <br />tested for the full ground water suite on a quarterly basis. <br />7) Additional SPLP tests will be conducted on the tailings once a quarter for the first year and <br />provided to the Division; if these SPLP tests show that the mill tailings area inert, no further <br />SPLP data will be provided to the Division over the life of the mine <br />8) Waste rock cannot make up more than 20% of the material to be placed in the permanent <br />piles, in order to prevent void spaces which may reduce compaction and provide conduits for <br />water flow. <br />Based on the apparent stability of the existing =reclaimed waste rock pile slopes in the area, a <br />detailed slope stability analysis was not performed on this material. Many of these older mines <br />have slopes as steep as 1.5H:1V compared to the 3H:1V proposed minimum slope of the <br />Revenue waste rock/tailings pile. Mine discharge water will no longer pass through the existing <br />waste rock as it does now with the Revenue Seep. Exhibit U presents a slope stability analysis <br />using commonly accepted circular failure equations and material parameters. The analysis <br />indicates that the waste embankment has a calculated safety factor above 1.5, which is well <br />above the minimum safety requirements for permanent slopes of 1.3. <br />Sediment Ponds 1 and 2 will contain all run off from the waste piles. The discharges from these <br />ponds will be tested for zinc, lead, and other dissolved metals based on the requirements of the <br />CDPHE discharge permit. Both ponds are temporary, and will therefore contain the 10 -yr event <br />while passing the 100 -yr event. Details of the ponds designs and requirements can be found in <br />Exhibit G. Information regarding the waste rock and tailings chemistry can be found in Exhibit <br />T. <br />Revenue Mine August 2012 D - <br />